From 0449647cf90156e0e7f62f66727e50b4f3de58bb Mon Sep 17 00:00:00 2001
From: Greyson Parrelli <greyson@signal.org>
Date: Fri, 6 Apr 2018 18:15:24 -0700
Subject: [PATCH] Implemented full-text search.

You can now use the search bar on the conversation list to find
conversations, messages, and contacts.
---
 build.gradle                                  |  12 +-
 res/drawable/header_search_background.xml     |  13 ++
 res/layout/fragment_search.xml                |  20 ++
 res/layout/header_search_result.xml           |  13 ++
 res/layout/load_more_header.xml               |  43 +++-
 res/values/strings.xml                        |   8 +
 .../securesms/ConversationActivity.java       |   1 +
 .../securesms/ConversationFragment.java       | 136 ++++++++---
 .../securesms/ConversationListActivity.java   |  48 +++-
 .../securesms/ConversationListItem.java       | 104 ++++++++-
 .../securesms/DatabaseUpgradeActivity.java    |   2 +
 .../thoughtcrime/securesms/ShareActivity.java |   2 +-
 .../securesms/components/SearchToolbar.java   |   5 +-
 .../securesms/contacts/ContactsDatabase.java  |   4 +-
 .../securesms/database/CursorList.java        | 191 +++++++++++++++
 .../securesms/database/DatabaseFactory.java   |   6 +
 .../securesms/database/MmsSmsDatabase.java    |  27 ++-
 .../securesms/database/SearchDatabase.java    |  89 +++++++
 .../securesms/database/ThreadDatabase.java    |   8 +-
 .../database/helpers/SQLCipherOpenHelper.java |  30 ++-
 .../database/loaders/ConversationLoader.java  |  16 +-
 .../securesms/search/SearchFragment.java      | 178 ++++++++++++++
 .../securesms/search/SearchListAdapter.java   | 219 ++++++++++++++++++
 .../securesms/search/SearchRepository.java    | 188 +++++++++++++++
 .../securesms/search/SearchViewModel.java     |  89 +++++++
 .../securesms/search/model/MessageResult.java |  27 +++
 .../securesms/search/model/SearchResult.java  |  64 +++++
 .../securesms/util/Debouncer.java             |  32 +++
 28 files changed, 1505 insertions(+), 70 deletions(-)
 create mode 100644 res/drawable/header_search_background.xml
 create mode 100644 res/layout/fragment_search.xml
 create mode 100644 res/layout/header_search_result.xml
 create mode 100644 src/org/thoughtcrime/securesms/database/CursorList.java
 create mode 100644 src/org/thoughtcrime/securesms/database/SearchDatabase.java
 create mode 100644 src/org/thoughtcrime/securesms/search/SearchFragment.java
 create mode 100644 src/org/thoughtcrime/securesms/search/SearchListAdapter.java
 create mode 100644 src/org/thoughtcrime/securesms/search/SearchRepository.java
 create mode 100644 src/org/thoughtcrime/securesms/search/SearchViewModel.java
 create mode 100644 src/org/thoughtcrime/securesms/search/model/MessageResult.java
 create mode 100644 src/org/thoughtcrime/securesms/search/model/SearchResult.java
 create mode 100644 src/org/thoughtcrime/securesms/util/Debouncer.java

diff --git a/build.gradle b/build.gradle
index b35d409be8..e8c37bfec4 100644
--- a/build.gradle
+++ b/build.gradle
@@ -39,6 +39,12 @@ repositories {
     maven {
         url "https://raw.github.com/signalapp/maven/master/circular-progress-button/releases/"
     }
+    maven {
+        url "https://raw.github.com/signalapp/maven/master/circular-progress-button/releases/"
+    }
+    maven {
+        url "https://raw.github.com/signalapp/maven/master/sqlcipher/release/"
+    }
     maven {
         url "https://maven.google.com"
     }
@@ -119,7 +125,7 @@ dependencies {
     }
     compile 'com.codewaves.stickyheadergrid:stickyheadergrid:0.9.4'
     compile 'com.github.dmytrodanylyk.circular-progress-button:library:1.1.3-S2'
-    compile 'net.zetetic:android-database-sqlcipher:3.5.9'
+    compile 'org.signal:android-database-sqlcipher:3.5.9-S1'
     compile ('com.googlecode.ez-vcard:ez-vcard:0.9.11') {
         exclude group: 'com.fasterxml.jackson.core'
         exclude group: 'org.freemarker'
@@ -192,7 +198,8 @@ dependencyVerification {
         'com.annimon:stream:5da6e2e3e0551d61a3ea7014f04312276549e3dd739cf637996e4cf43c5535b9',
         'com.takisoft.fix:colorpicker:f5d0dbabe406a1800498ca9c1faf34db36e021d8488bf10360f29961fe3ab0d1',
         'com.github.dmytrodanylyk.circular-progress-button:library:8dc6a29a5a8db7b2ad5a9a7fda1dc9ae0893f4c8f0545732b2c63854ea693e8e',
-        'net.zetetic:android-database-sqlcipher:eff93b3222f4bdc349ffee2d2e3b2a2507241f17435fb998947bcce486618f1d',
+        'org.signal:android-database-sqlcipher:4302551df258883cc5dc5d62ddb141a6b5b8f113d77d70322dc2648c0856ccef',
+        'com.googlecode.ez-vcard:ez-vcard:7e24ad50b222d2f70ac91bdccfa3c0f6200b078d797cb784837f75e77bb4210f',
         'com.google.android.gms:play-services-iid:54e919f9957b8b7820da7ee9b83471d00d0cac1cf08ddea8b5b41aea80bb1a70',
         'com.google.android.gms:play-services-base:0ca636a8fc9a5af45e607cdcd61783bf5d561cbbb0f862021ce69606eee5ad49',
         'com.google.android.gms:play-services-tasks:69ec265168e601d0203d04cd42e34bb019b2f029aa1e16fabd38a5153eea2086',
@@ -223,6 +230,7 @@ dependencyVerification {
         'javax.inject:javax.inject:91c77044a50c481636c32d916fd89c9118a72195390452c81065080f957de7ff',
         'com.klinkerapps:logger:177e325259a8b111ad6745ec10db5861723c99f402222b80629f576f49408541',
         'com.google.android:flexbox:a9989fd13ae2ee42765dfc515fe362edf4f326e74925d02a10369df8092a4935',
+        'org.jsoup:jsoup:abeaf34795a4de70f72aed6de5966d2955ec7eb348eeb813324f23c999575473',
         'org.whispersystems:curve25519-android:82595394422b957d4a5b5f1b27b75ba25cf6dc4db4d312418ca38cd6fff279ca',
         'org.whispersystems:signal-protocol-java:5152c2b01a25147967d6bf82e540f947901bdfa79260be3eb3e96b03f787d6b5',
         'com.google.protobuf:protobuf-java:e0c1c64575c005601725e7c6a02cebf9e1285e888f756b2a1d73ffa8d725cc74',
diff --git a/res/drawable/header_search_background.xml b/res/drawable/header_search_background.xml
new file mode 100644
index 0000000000..2331f677bc
--- /dev/null
+++ b/res/drawable/header_search_background.xml
@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
+    <item>
+        <shape android:shape="rectangle" >
+            <solid android:color="@color/grey_200"/>
+        </shape>
+    </item>
+    <item android:top="1dp">
+        <shape android:shape="rectangle" >
+            <solid android:color="@color/white" />
+        </shape>
+    </item>
+</layer-list>
diff --git a/res/layout/fragment_search.xml b/res/layout/fragment_search.xml
new file mode 100644
index 0000000000..d273167dd1
--- /dev/null
+++ b/res/layout/fragment_search.xml
@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+<FrameLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+    <TextView
+        android:id="@+id/search_no_results"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:gravity="center"
+        android:background="@color/white"
+        android:visibility="gone" />
+
+    <android.support.v7.widget.RecyclerView
+        android:id="@+id/search_list"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"/>
+
+</FrameLayout>
\ No newline at end of file
diff --git a/res/layout/header_search_result.xml b/res/layout/header_search_result.xml
new file mode 100644
index 0000000000..7b8eed1cee
--- /dev/null
+++ b/res/layout/header_search_result.xml
@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<TextView
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    style="@style/Base.TextAppearance.AppCompat.Body2"
+    android:orientation="vertical"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:padding="8dp"
+    android:background="@drawable/header_search_background"
+    tools:text="Conversations">
+
+</TextView>
\ No newline at end of file
diff --git a/res/layout/load_more_header.xml b/res/layout/load_more_header.xml
index 0ef8c29de9..1785c28d76 100644
--- a/res/layout/load_more_header.xml
+++ b/res/layout/load_more_header.xml
@@ -1,9 +1,48 @@
 <?xml version="1.0" encoding="utf-8"?>
-<Button xmlns:android="http://schemas.android.com/apk/res/android"
+
+<ViewSwitcher
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    xmlns:wheel="http://schemas.android.com/apk/res-auto"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:background="?conversation_item_bubble_background"
+    android:padding="16dp"
+    android:elevation="2dp">
+
+    <TextView
+        style="@style/Base.TextAppearance.AppCompat.Button"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:layout_gravity="center"
-        android:background="?conversation_item_bubble_background"
+        android:gravity="center"
         android:textColor="?conversation_item_sent_text_primary_color"
         android:text="@string/load_more_header__see_full_conversation" />
 
+    <LinearLayout
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:orientation="horizontal"
+        android:layout_gravity="center">
+
+        <TextView
+            style="@style/Base.TextAppearance.AppCompat.Button"
+            android:id="@+id/load_more_title"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_gravity="center_vertical"
+            android:textColor="?conversation_item_sent_text_primary_color"
+            android:text="@string/load_more_header__loading" />
+
+        <com.pnikosis.materialishprogress.ProgressWheel
+            android:id="@+id/load_more_progress"
+            android:layout_width="20dp"
+            android:layout_height="20dp"
+            android:layout_gravity="center_vertical"
+            android:layout_marginStart="11dp"
+            android:layout_marginLeft="11dp"
+            wheel:matProg_progressIndeterminate="true"
+            tools:ignore="RtlSymmetry" />
+
+    </LinearLayout>
+</ViewSwitcher>
\ No newline at end of file
diff --git a/res/values/strings.xml b/res/values/strings.xml
index 7de830a629..763c38a404 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -584,6 +584,13 @@
     <string name="RingtonePreference_add_ringtone_text">Add ringtone</string>
     <string name="RingtonePreference_unable_to_add_ringtone">Unable to add custom ringtone</string>
 
+    <!-- Search -->
+    <string name="SearchFragment_begin_searching">Begin typing to search for conversations, messages, and contacts.</string>
+    <string name="SearchFragment_no_results">No results found for \'%s\'</string>
+    <string name="SearchFragment_header_conversations">Conversations</string>
+    <string name="SearchFragment_header_contacts">Contacts</string>
+    <string name="SearchFragment_header_messages">Messages</string>
+
     <!-- SharedContactDetailsActivity -->
     <string name="SharedContactDetailsActivity_add_to_contacts">Add to Contacts</string>
     <string name="SharedContactDetailsActivity_invite_to_signal">Invite to Signal</string>
@@ -980,6 +987,7 @@
 
     <!-- load_more_header -->
     <string name="load_more_header__see_full_conversation">See full conversation</string>
+    <string name="load_more_header__loading">Loading</string>
 
     <!-- media_overview_activity -->
     <string name="media_overview_activity__no_media">No media</string>
diff --git a/src/org/thoughtcrime/securesms/ConversationActivity.java b/src/org/thoughtcrime/securesms/ConversationActivity.java
index db63899703..e91c03fbc3 100644
--- a/src/org/thoughtcrime/securesms/ConversationActivity.java
+++ b/src/org/thoughtcrime/securesms/ConversationActivity.java
@@ -210,6 +210,7 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
   public static final String DISTRIBUTION_TYPE_EXTRA = "distribution_type";
   public static final String TIMING_EXTRA            = "timing";
   public static final String LAST_SEEN_EXTRA         = "last_seen";
+  public static final String STARTING_POSITION_EXTRA = "starting_position";
 
   private static final int PICK_GALLERY        = 1;
   private static final int PICK_DOCUMENT       = 2;
diff --git a/src/org/thoughtcrime/securesms/ConversationFragment.java b/src/org/thoughtcrime/securesms/ConversationFragment.java
index f91b9236d7..0ce45ba42c 100644
--- a/src/org/thoughtcrime/securesms/ConversationFragment.java
+++ b/src/org/thoughtcrime/securesms/ConversationFragment.java
@@ -51,6 +51,7 @@ import android.view.animation.Animation;
 import android.view.animation.AnimationUtils;
 import android.widget.TextView;
 import android.widget.Toast;
+import android.widget.ViewSwitcher;
 
 import org.thoughtcrime.securesms.ConversationAdapter.HeaderViewHolder;
 import org.thoughtcrime.securesms.ConversationAdapter.ItemClickListener;
@@ -90,10 +91,12 @@ import java.util.Set;
 public class ConversationFragment extends Fragment
   implements LoaderManager.LoaderCallbacks<Cursor>
 {
-  private static final String TAG = ConversationFragment.class.getSimpleName();
+  private static final String TAG       = ConversationFragment.class.getSimpleName();
+  private static final String KEY_LIMIT = "limit";
 
-  private static final long PARTIAL_CONVERSATION_LIMIT = 500L;
-  private static final int  CODE_ADD_EDIT_CONTACT      = 77;
+  private static final int PARTIAL_CONVERSATION_LIMIT = 500;
+  private static final int SCROLL_ANIMATION_THRESHOLD = 50;
+  private static final int CODE_ADD_EDIT_CONTACT      = 77;
 
   private final ActionModeCallback actionModeCallback     = new ActionModeCallback();
   private final ItemClickListener  selectionClickListener = new ConversationFragmentItemClickListener();
@@ -103,12 +106,16 @@ public class ConversationFragment extends Fragment
   private Recipient                   recipient;
   private long                        threadId;
   private long                        lastSeen;
+  private int                         startingPosition;
+  private int                         previousOffset;
   private boolean                     firstLoad;
+  private long                        loaderStartTime;
   private ActionMode                  actionMode;
   private Locale                      locale;
   private RecyclerView                list;
   private RecyclerView.ItemDecoration lastSeenDecoration;
-  private View                        loadMoreView;
+  private ViewSwitcher                topLoadMoreView;
+  private ViewSwitcher                bottomLoadMoreView;
   private UnknownSenderView           unknownSenderView;
   private View                        composeDivider;
   private View                        scrollToBottomButton;
@@ -135,12 +142,10 @@ public class ConversationFragment extends Fragment
     list.setLayoutManager(layoutManager);
     list.setItemAnimator(null);
 
-    loadMoreView = inflater.inflate(R.layout.load_more_header, container, false);
-    loadMoreView.setOnClickListener(v -> {
-      Bundle args = new Bundle();
-      args.putLong("limit", 0);
-      getLoaderManager().restartLoader(0, args, ConversationFragment.this);
-    });
+    topLoadMoreView    = (ViewSwitcher) inflater.inflate(R.layout.load_more_header, container, false);
+    bottomLoadMoreView = (ViewSwitcher) inflater.inflate(R.layout.load_more_header, container, false);
+    initializeLoadMoreView(topLoadMoreView);
+    initializeLoadMoreView(bottomLoadMoreView);
 
     return view;
   }
@@ -189,6 +194,7 @@ public class ConversationFragment extends Fragment
     this.recipient         = Recipient.from(getActivity(), getActivity().getIntent().getParcelableExtra(ConversationActivity.ADDRESS_EXTRA), true);
     this.threadId          = this.getActivity().getIntent().getLongExtra(ConversationActivity.THREAD_ID_EXTRA, -1);
     this.lastSeen          = this.getActivity().getIntent().getLongExtra(ConversationActivity.LAST_SEEN_EXTRA, -1);
+    this.startingPosition  = this.getActivity().getIntent().getIntExtra(ConversationActivity.STARTING_POSITION_EXTRA, -1);
     this.firstLoad         = true;
     this.unknownSenderView = new UnknownSenderView(getActivity(), recipient, threadId);
 
@@ -207,6 +213,16 @@ public class ConversationFragment extends Fragment
     }
   }
 
+  private void initializeLoadMoreView(ViewSwitcher loadMoreView) {
+    loadMoreView.setOnClickListener(v -> {
+      Bundle args = new Bundle();
+      args.putInt(KEY_LIMIT, 0);
+      getLoaderManager().restartLoader(0, args, ConversationFragment.this);
+      loadMoreView.showNext();
+      loadMoreView.setOnClickListener(null);
+    });
+  }
+
   private void setCorrectMenuVisibility(Menu menu) {
     Set<MessageRecord> messageRecords = getListAdapter().getSelectedItems();
     boolean            actionMessage  = false;
@@ -278,7 +294,11 @@ public class ConversationFragment extends Fragment
   }
 
   public void scrollToBottom() {
-    list.smoothScrollToPosition(0);
+    if (((LinearLayoutManager) list.getLayoutManager()).findFirstVisibleItemPosition() < SCROLL_ANIMATION_THRESHOLD) {
+      list.smoothScrollToPosition(0);
+    } else {
+      list.scrollToPosition(0);
+    }
   }
 
   public void setLastSeen(long lastSeen) {
@@ -424,43 +444,76 @@ public class ConversationFragment extends Fragment
 
   @Override
   public Loader<Cursor> onCreateLoader(int id, Bundle args) {
-    return new ConversationLoader(getActivity(), threadId, args.getLong("limit", PARTIAL_CONVERSATION_LIMIT), lastSeen);
+    Log.w(TAG, "onCreateLoader");
+    loaderStartTime = System.currentTimeMillis();
+
+    int limit  = args.getInt(KEY_LIMIT, PARTIAL_CONVERSATION_LIMIT);
+    int offset = 0;
+    if (limit != 0 && startingPosition > limit) {
+      offset = Math.max(startingPosition - (limit / 2) + 1, 0);
+      startingPosition -= offset - 1;
+    }
+
+    return new ConversationLoader(getActivity(), threadId, offset, limit, lastSeen);
   }
 
   @Override
   public void onLoadFinished(Loader<Cursor> cursorLoader, Cursor cursor) {
-    Log.w(TAG, "onLoadFinished");
+    long loadTime = System.currentTimeMillis() - loaderStartTime;
+    int  count    = cursor.getCount();
+    Log.w(TAG, "onLoadFinished - took " + loadTime + " ms to load a cursor of size " + count);
     ConversationLoader loader = (ConversationLoader)cursorLoader;
 
-    if (list.getAdapter() != null) {
-      if (cursor.getCount() >= PARTIAL_CONVERSATION_LIMIT && loader.hasLimit()) {
-        getListAdapter().setFooterView(loadMoreView);
+    ConversationAdapter adapter = getListAdapter();
+    if (adapter == null) {
+      return;
+    }
+
+    if (cursor.getCount() >= PARTIAL_CONVERSATION_LIMIT && loader.hasLimit()) {
+      adapter.setFooterView(topLoadMoreView);
+    } else {
+      adapter.setFooterView(null);
+    }
+
+    if (lastSeen == -1) {
+      setLastSeen(loader.getLastSeen());
+    }
+
+    if (!loader.hasSent() && !recipient.isSystemContact() && !recipient.isGroupRecipient() && recipient.getRegistered() == RecipientDatabase.RegisteredState.REGISTERED) {
+      adapter.setHeaderView(unknownSenderView);
+    } else {
+      adapter.setHeaderView(null);
+    }
+
+    if (loader.hasOffset()) {
+      adapter.setHeaderView(bottomLoadMoreView);
+      previousOffset = loader.getOffset();
+    }
+
+    adapter.changeCursor(cursor);
+
+    int lastSeenPosition = adapter.findLastSeenPosition(lastSeen);
+
+    if (firstLoad) {
+      if (startingPosition >= 0) {
+        scrollToStartingPosition(startingPosition);
       } else {
-        getListAdapter().setFooterView(null);
-      }
-
-      if (lastSeen == -1) {
-        setLastSeen(loader.getLastSeen());
-      }
-
-      if (!loader.hasSent() && !recipient.isSystemContact() && !recipient.isGroupRecipient() && recipient.getRegistered() == RecipientDatabase.RegisteredState.REGISTERED) {
-        getListAdapter().setHeaderView(unknownSenderView);
-      } else {
-        getListAdapter().setHeaderView(null);
-      }
-
-      getListAdapter().changeCursor(cursor);
-
-      int lastSeenPosition = getListAdapter().findLastSeenPosition(lastSeen);
-
-      if (firstLoad) {
         scrollToLastSeenPosition(lastSeenPosition);
-        firstLoad = false;
       }
+      firstLoad = false;
+    } else if (previousOffset > 0) {
+      int scrollPosition = previousOffset + ((LinearLayoutManager) list.getLayoutManager()).findFirstVisibleItemPosition();
+      scrollPosition = Math.min(scrollPosition, count - 1);
 
-      if (lastSeenPosition <= 0) {
-        setLastSeen(0);
-      }
+      View firstView = list.getLayoutManager().getChildAt(scrollPosition);
+      int pixelOffset = (firstView == null) ? 0 : (firstView.getBottom() - list.getPaddingBottom());
+
+      ((LinearLayoutManager) list.getLayoutManager()).scrollToPositionWithOffset(scrollPosition, pixelOffset);
+      previousOffset = 0;
+    }
+
+    if (lastSeenPosition <= 0) {
+      setLastSeen(0);
     }
   }
 
@@ -501,6 +554,13 @@ public class ConversationFragment extends Fragment
     }
   }
 
+  private void scrollToStartingPosition(final int startingPosition) {
+    list.post(() -> {
+      list.getLayoutManager().scrollToPosition(startingPosition);
+      getListAdapter().pulseHighlightItem(startingPosition);
+    });
+  }
+
   private void scrollToLastSeenPosition(final int lastSeenPosition) {
     if (lastSeenPosition > 0) {
       list.post(() -> ((LinearLayoutManager)list.getLayoutManager()).scrollToPositionWithOffset(lastSeenPosition, list.getHeight()));
diff --git a/src/org/thoughtcrime/securesms/ConversationListActivity.java b/src/org/thoughtcrime/securesms/ConversationListActivity.java
index 2dbfba3039..991c573ab4 100644
--- a/src/org/thoughtcrime/securesms/ConversationListActivity.java
+++ b/src/org/thoughtcrime/securesms/ConversationListActivity.java
@@ -25,9 +25,12 @@ import android.net.Uri;
 import android.os.AsyncTask;
 import android.os.Bundle;
 import android.support.v7.widget.Toolbar;
+import android.text.TextUtils;
+import android.util.Log;
 import android.view.Menu;
 import android.view.MenuInflater;
 import android.view.MenuItem;
+import android.view.ViewGroup;
 import android.widget.ImageView;
 import android.widget.Toast;
 
@@ -40,6 +43,7 @@ import org.thoughtcrime.securesms.notifications.MarkReadReceiver;
 import org.thoughtcrime.securesms.notifications.MessageNotifier;
 import org.thoughtcrime.securesms.permissions.Permissions;
 import org.thoughtcrime.securesms.recipients.Recipient;
+import org.thoughtcrime.securesms.search.SearchFragment;
 import org.thoughtcrime.securesms.service.KeyCachingService;
 import org.thoughtcrime.securesms.util.DynamicLanguage;
 import org.thoughtcrime.securesms.util.DynamicNoActionBarTheme;
@@ -57,9 +61,11 @@ public class ConversationListActivity extends PassphraseRequiredActionBarActivit
   private final DynamicTheme    dynamicTheme    = new DynamicNoActionBarTheme();
   private final DynamicLanguage dynamicLanguage = new DynamicLanguage();
 
-  private ConversationListFragment fragment;
+  private ConversationListFragment conversationListFragment;
+  private SearchFragment           searchFragment;
   private SearchToolbar            searchToolbar;
   private ImageView                searchAction;
+  private ViewGroup                fragmentContainer;
 
   @Override
   protected void onPreCreate() {
@@ -74,9 +80,10 @@ public class ConversationListActivity extends PassphraseRequiredActionBarActivit
     Toolbar toolbar = findViewById(R.id.toolbar);
     setSupportActionBar(toolbar);
 
-    searchToolbar = findViewById(R.id.search_toolbar);
-    searchAction  = findViewById(R.id.search_action);
-    fragment      = initFragment(R.id.fragment_container, new ConversationListFragment(), dynamicLanguage.getCurrentLocale());
+    searchToolbar            = findViewById(R.id.search_toolbar);
+    searchAction             = findViewById(R.id.search_action);
+    fragmentContainer        = findViewById(R.id.fragment_container);
+    conversationListFragment = initFragment(R.id.fragment_container, new ConversationListFragment(), dynamicLanguage.getCurrentLocale());
 
     initializeSearchListener();
 
@@ -123,15 +130,31 @@ public class ConversationListActivity extends PassphraseRequiredActionBarActivit
     searchToolbar.setListener(new SearchToolbar.SearchListener() {
       @Override
       public void onSearchTextChange(String text) {
-        if (fragment != null) {
-          fragment.setQueryFilter(text);
+        String trimmed = text.trim();
+
+        if (trimmed.length() > 0) {
+          if (searchFragment == null) {
+            searchFragment = SearchFragment.newInstance(dynamicLanguage.getCurrentLocale());
+            getSupportFragmentManager().beginTransaction()
+                                       .add(R.id.fragment_container, searchFragment, null)
+                                       .commit();
+          }
+          searchFragment.updateSearchQuery(trimmed);
+        } else if (searchFragment != null) {
+          getSupportFragmentManager().beginTransaction()
+                                     .remove(searchFragment)
+                                     .commit();
+          searchFragment = null;
         }
       }
 
       @Override
-      public void onSearchReset() {
-        if (fragment != null) {
-          fragment.resetQueryFilter();
+      public void onSearchClosed() {
+        if (searchFragment != null) {
+          getSupportFragmentManager().beginTransaction()
+                                     .remove(searchFragment)
+                                     .commit();
+          searchFragment = null;
         }
       }
     });
@@ -156,12 +179,19 @@ public class ConversationListActivity extends PassphraseRequiredActionBarActivit
 
   @Override
   public void onCreateConversation(long threadId, Recipient recipient, int distributionType, long lastSeen) {
+    openConversation(threadId, recipient, distributionType, lastSeen, -1);
+  }
+
+  public void openConversation(long threadId, Recipient recipient, int distributionType, long lastSeen, int startingPosition) {
+    searchToolbar.clearFocus();
+
     Intent intent = new Intent(this, ConversationActivity.class);
     intent.putExtra(ConversationActivity.ADDRESS_EXTRA, recipient.getAddress());
     intent.putExtra(ConversationActivity.THREAD_ID_EXTRA, threadId);
     intent.putExtra(ConversationActivity.DISTRIBUTION_TYPE_EXTRA, distributionType);
     intent.putExtra(ConversationActivity.TIMING_EXTRA, System.currentTimeMillis());
     intent.putExtra(ConversationActivity.LAST_SEEN_EXTRA, lastSeen);
+    intent.putExtra(ConversationActivity.STARTING_POSITION_EXTRA, startingPosition);
 
     startActivity(intent);
     overridePendingTransition(R.anim.slide_from_right, R.anim.fade_scale_out);
diff --git a/src/org/thoughtcrime/securesms/ConversationListItem.java b/src/org/thoughtcrime/securesms/ConversationListItem.java
index f173220d5c..68515e4733 100644
--- a/src/org/thoughtcrime/securesms/ConversationListItem.java
+++ b/src/org/thoughtcrime/securesms/ConversationListItem.java
@@ -24,6 +24,11 @@ import android.graphics.drawable.RippleDrawable;
 import android.os.Build.VERSION;
 import android.os.Build.VERSION_CODES;
 import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.text.Spannable;
+import android.text.SpannableString;
+import android.text.Spanned;
+import android.text.style.StyleSpan;
 import android.util.AttributeSet;
 import android.view.View;
 import android.widget.ImageView;
@@ -41,10 +46,12 @@ import org.thoughtcrime.securesms.database.model.ThreadRecord;
 import org.thoughtcrime.securesms.mms.GlideRequests;
 import org.thoughtcrime.securesms.recipients.Recipient;
 import org.thoughtcrime.securesms.recipients.RecipientModifiedListener;
+import org.thoughtcrime.securesms.search.model.MessageResult;
 import org.thoughtcrime.securesms.util.DateUtils;
 import org.thoughtcrime.securesms.util.Util;
 import org.thoughtcrime.securesms.util.ViewUtil;
 
+import java.util.Collections;
 import java.util.Locale;
 import java.util.Set;
 
@@ -57,8 +64,9 @@ public class ConversationListItem extends RelativeLayout
   @SuppressWarnings("unused")
   private final static String TAG = ConversationListItem.class.getSimpleName();
 
-  private final static Typeface BOLD_TYPEFACE  = Typeface.create("sans-serif", Typeface.BOLD);
-  private final static Typeface LIGHT_TYPEFACE = Typeface.create("sans-serif-light", Typeface.NORMAL);
+  private final static Typeface  BOLD_TYPEFACE  = Typeface.create("sans-serif", Typeface.BOLD);
+  private final static Typeface  LIGHT_TYPEFACE = Typeface.create("sans-serif-light", Typeface.NORMAL);
+  private final static StyleSpan BOLD_SPAN      = new StyleSpan(Typeface.BOLD);
 
   private Set<Long>          selectedThreads;
   private Recipient          recipient;
@@ -107,8 +115,20 @@ public class ConversationListItem extends RelativeLayout
 
   @Override
   public void bind(@NonNull ThreadRecord thread,
-                   @NonNull GlideRequests glideRequests, @NonNull Locale locale,
-                   @NonNull Set<Long> selectedThreads, boolean batchMode)
+                   @NonNull GlideRequests glideRequests,
+                   @NonNull Locale locale,
+                   @NonNull Set<Long> selectedThreads,
+                   boolean batchMode)
+  {
+    bind(thread, glideRequests, locale, selectedThreads, batchMode, null);
+  }
+
+  public void bind(@NonNull ThreadRecord thread,
+                   @NonNull GlideRequests glideRequests,
+                   @NonNull Locale locale,
+                   @NonNull Set<Long> selectedThreads,
+                   boolean batchMode,
+                   @Nullable String highlightSubstring)
   {
     this.selectedThreads  = selectedThreads;
     this.recipient        = thread.getRecipient();
@@ -119,7 +139,11 @@ public class ConversationListItem extends RelativeLayout
     this.lastSeen         = thread.getLastSeen();
 
     this.recipient.addListener(this);
-    this.fromView.setText(recipient, unreadCount == 0);
+    if (highlightSubstring != null) {
+      this.fromView.setText(getHighlightedSpan(locale, recipient.getName(), highlightSubstring));
+    } else {
+      this.fromView.setText(recipient, unreadCount == 0);
+    }
 
     this.subjectView.setText(thread.getDisplayBody());
 //    this.subjectView.setTypeface(read ? LIGHT_TYPEFACE : BOLD_TYPEFACE);
@@ -144,6 +168,56 @@ public class ConversationListItem extends RelativeLayout
     this.contactPhotoImage.setAvatar(glideRequests, recipient, true);
   }
 
+  public void bind(@NonNull  Recipient     contact,
+                   @NonNull  GlideRequests glideRequests,
+                   @NonNull  Locale        locale,
+                   @Nullable String        highlightSubstring)
+  {
+    this.selectedThreads = Collections.emptySet();
+    this.recipient       = contact;
+    this.glideRequests   = glideRequests;
+
+    this.recipient.addListener(this);
+
+    fromView.setText(getHighlightedSpan(locale, recipient.getName(), highlightSubstring));
+    subjectView.setText(contact.getAddress().toPhoneString());
+    dateView.setText("");
+    archivedView.setVisibility(GONE);
+    unreadIndicator.setVisibility(GONE);
+    deliveryStatusIndicator.setNone();
+    alertView.setNone();
+    thumbnailView.setVisibility(GONE);
+
+    setBatchState(false);
+    setRippleColor(contact);
+    contactPhotoImage.setAvatar(glideRequests, recipient, true);
+  }
+
+  public void bind(@NonNull  MessageResult messageResult,
+                   @NonNull  GlideRequests glideRequests,
+                   @NonNull  Locale        locale,
+                   @Nullable String        highlightSubstring)
+  {
+    this.selectedThreads = Collections.emptySet();
+    this.recipient       = messageResult.recipient;
+    this.glideRequests   = glideRequests;
+
+    this.recipient.addListener(this);
+
+    fromView.setText(recipient, true);
+    subjectView.setText(getHighlightedSpan(locale, messageResult.bodySnippet, highlightSubstring));
+    dateView.setText(DateUtils.getBriefRelativeTimeSpanString(getContext(), locale, messageResult.receivedTimestampMs));
+    archivedView.setVisibility(GONE);
+    unreadIndicator.setVisibility(GONE);
+    deliveryStatusIndicator.setNone();
+    alertView.setNone();
+    thumbnailView.setVisibility(GONE);
+
+    setBatchState(false);
+    setRippleColor(recipient);
+    contactPhotoImage.setAvatar(glideRequests, recipient, true);
+  }
+
   @Override
   public void unbind() {
     if (this.recipient != null) this.recipient.removeListener(this);
@@ -241,6 +315,26 @@ public class ConversationListItem extends RelativeLayout
     unreadIndicator.setVisibility(View.VISIBLE);
   }
 
+  private Spanned getHighlightedSpan(@NonNull Locale locale,
+                                     @Nullable String value,
+                                     @Nullable String highlight)
+  {
+    if (value == null || highlight == null) {
+      return new SpannableString(value);
+    }
+
+    int startPosition = value.toLowerCase(locale).indexOf(highlight.toLowerCase());
+    int endPosition   = startPosition + highlight.length();
+
+    if (startPosition < 0) {
+      return new SpannableString(value);
+    }
+
+    Spannable spanned = new SpannableString(value);
+    spanned.setSpan(BOLD_SPAN, startPosition, endPosition, Spannable.SPAN_INCLUSIVE_EXCLUSIVE);
+    return spanned;
+  }
+
   @Override
   public void onModified(final Recipient recipient) {
     Util.runOnMain(() -> {
diff --git a/src/org/thoughtcrime/securesms/DatabaseUpgradeActivity.java b/src/org/thoughtcrime/securesms/DatabaseUpgradeActivity.java
index 7681733bcd..6f07662046 100644
--- a/src/org/thoughtcrime/securesms/DatabaseUpgradeActivity.java
+++ b/src/org/thoughtcrime/securesms/DatabaseUpgradeActivity.java
@@ -81,6 +81,7 @@ public class DatabaseUpgradeActivity extends BaseActivity {
   public static final int SQLCIPHER_COMPLETE                   = 352;
   public static final int REMOVE_JOURNAL                       = 353;
   public static final int REMOVE_CACHE                         = 354;
+  public static final int FULL_TEXT_SEARCH                     = 358;
 
   private static final SortedSet<Integer> UPGRADE_VERSIONS = new TreeSet<Integer>() {{
     add(NO_MORE_KEY_EXCHANGE_PREFIX_VERSION);
@@ -101,6 +102,7 @@ public class DatabaseUpgradeActivity extends BaseActivity {
     add(SQLCIPHER);
     add(SQLCIPHER_COMPLETE);
     add(REMOVE_CACHE);
+    add(FULL_TEXT_SEARCH);
   }};
 
   private MasterSecret masterSecret;
diff --git a/src/org/thoughtcrime/securesms/ShareActivity.java b/src/org/thoughtcrime/securesms/ShareActivity.java
index 96195e3e8a..60ace0ebe6 100644
--- a/src/org/thoughtcrime/securesms/ShareActivity.java
+++ b/src/org/thoughtcrime/securesms/ShareActivity.java
@@ -175,7 +175,7 @@ public class ShareActivity extends PassphraseRequiredActionBarActivity
       }
 
       @Override
-      public void onSearchReset() {
+      public void onSearchClosed() {
         if (contactsFragment != null) {
           contactsFragment.resetQueryFilter();
         }
diff --git a/src/org/thoughtcrime/securesms/components/SearchToolbar.java b/src/org/thoughtcrime/securesms/components/SearchToolbar.java
index c5714bf950..f645f8f157 100644
--- a/src/org/thoughtcrime/securesms/components/SearchToolbar.java
+++ b/src/org/thoughtcrime/securesms/components/SearchToolbar.java
@@ -120,7 +120,8 @@ public class SearchToolbar extends LinearLayout {
   private void hide() {
     if (getVisibility() == View.VISIBLE) {
 
-      if (listener != null) listener.onSearchReset();
+
+      if (listener != null) listener.onSearchClosed();
 
       if (Build.VERSION.SDK_INT >= 21) {
         Animator animator = ViewAnimationUtils.createCircularReveal(this, (int)x, (int)y, getWidth(), 0);
@@ -149,7 +150,7 @@ public class SearchToolbar extends LinearLayout {
 
   public interface SearchListener {
     void onSearchTextChange(String text);
-    void onSearchReset();
+    void onSearchClosed();
   }
 
 }
diff --git a/src/org/thoughtcrime/securesms/contacts/ContactsDatabase.java b/src/org/thoughtcrime/securesms/contacts/ContactsDatabase.java
index e228383ca8..72d00c143f 100644
--- a/src/org/thoughtcrime/securesms/contacts/ContactsDatabase.java
+++ b/src/org/thoughtcrime/securesms/contacts/ContactsDatabase.java
@@ -145,7 +145,7 @@ public class ContactsDatabase {
   }
 
   @SuppressLint("Recycle")
-  @NonNull Cursor querySystemContacts(@Nullable String filter) {
+  public @NonNull Cursor querySystemContacts(@Nullable String filter) {
     Uri uri;
 
     if (!TextUtils.isEmpty(filter)) {
@@ -193,7 +193,7 @@ public class ContactsDatabase {
   }
 
   @SuppressLint("Recycle")
-  @NonNull Cursor queryTextSecureContacts(String filter) {
+  public @NonNull Cursor queryTextSecureContacts(String filter) {
     String[] projection = new String[] {ContactsContract.Contacts.DISPLAY_NAME,
                                         ContactsContract.Data.DATA1};
 
diff --git a/src/org/thoughtcrime/securesms/database/CursorList.java b/src/org/thoughtcrime/securesms/database/CursorList.java
new file mode 100644
index 0000000000..218550e3ef
--- /dev/null
+++ b/src/org/thoughtcrime/securesms/database/CursorList.java
@@ -0,0 +1,191 @@
+package org.thoughtcrime.securesms.database;
+
+import android.database.Cursor;
+import android.database.MatrixCursor;
+import android.support.annotation.NonNull;
+
+import java.io.Closeable;
+import java.util.Collection;
+import java.util.Iterator;
+import java.util.List;
+import java.util.ListIterator;
+
+/**
+ * A list backed by a {@link Cursor} that retrieves models using a provided {@link ModelBuilder}.
+ * Allows you to abstract away the use of a {@link Cursor} while still getting the benefits of a
+ * {@link Cursor} (e.g. windowing).
+ *
+ * The one special consideration that must be made is that because this contains a cursor, you must
+ * call {@link #close()} when you are finished with it.
+ *
+ * Given that this is cursor-backed, it is effectively immutable.
+ */
+public class CursorList<T> implements List<T>, Closeable {
+
+  private static final Cursor EMPTY_CURSOR = new MatrixCursor(new String[] { "a" }, 0);
+
+  private final Cursor          cursor;
+  private final ModelBuilder<T> modelBuilder;
+
+  public CursorList(@NonNull Cursor cursor, @NonNull ModelBuilder<T> modelBuilder) {
+    this.cursor       = cursor;
+    this.modelBuilder = modelBuilder;
+
+    this.cursor.moveToFirst();
+  }
+
+  public static <T> CursorList<T> emptyList() {
+    //noinspection ConstantConditions,unchecked
+    return (CursorList<T>) new CursorList(EMPTY_CURSOR, null);
+  }
+
+  @Override
+  public int size() {
+    return cursor.getCount();
+  }
+
+  @Override
+  public boolean isEmpty() {
+    return size() == 0;
+  }
+
+  @Override
+  public boolean contains(Object o) {
+    throw new UnsupportedOperationException();
+  }
+
+  @NonNull
+  @Override
+  public Iterator<T> iterator() {
+    return new Iterator<T>() {
+      @Override
+      public boolean hasNext() {
+        return cursor.getCount() > 0 && !cursor.isLast();
+      }
+
+      @Override
+      public T next() {
+        T model = modelBuilder.build(cursor);
+        cursor.moveToNext();
+        return model;
+      }
+    };
+  }
+
+  @NonNull
+  @Override
+  public Object[] toArray() {
+    Object[] out = new Object[size()];
+    for (int i = 0; i < cursor.getCount(); i++) {
+      cursor.moveToPosition(i);
+      out[i] = modelBuilder.build(cursor);
+    }
+    return out;
+  }
+
+  @Override
+  public boolean add(T o) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public boolean remove(Object o) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public boolean addAll(@NonNull Collection collection) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public boolean addAll(int i, @NonNull Collection collection) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void clear() {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public T get(int i) {
+    cursor.moveToPosition(i);
+    return modelBuilder.build(cursor);
+  }
+
+  @Override
+  public T set(int i, T o) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void add(int i, T o) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public T remove(int i) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public int indexOf(Object o) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public int lastIndexOf(Object o) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public ListIterator<T> listIterator() {
+    throw new UnsupportedOperationException();
+  }
+
+  @NonNull
+  @Override
+  public ListIterator<T> listIterator(int i) {
+    throw new UnsupportedOperationException();
+  }
+
+  @NonNull
+  @Override
+  public List<T> subList(int i, int i1) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public boolean retainAll(@NonNull Collection collection) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public boolean removeAll(@NonNull Collection collection) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public boolean containsAll(@NonNull Collection collection) {
+    throw new UnsupportedOperationException();
+  }
+
+  @NonNull
+  @Override
+  public T[] toArray(@NonNull Object[] objects) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public void close() {
+    if (cursor != null) {
+      cursor.close();
+    }
+  }
+
+  public interface ModelBuilder<T> {
+    T build(@NonNull Cursor cursor);
+  }
+}
+
diff --git a/src/org/thoughtcrime/securesms/database/DatabaseFactory.java b/src/org/thoughtcrime/securesms/database/DatabaseFactory.java
index 0c67c74b18..8709e486d2 100644
--- a/src/org/thoughtcrime/securesms/database/DatabaseFactory.java
+++ b/src/org/thoughtcrime/securesms/database/DatabaseFactory.java
@@ -56,6 +56,7 @@ public class DatabaseFactory {
   private final OneTimePreKeyDatabase preKeyDatabase;
   private final SignedPreKeyDatabase  signedPreKeyDatabase;
   private final SessionDatabase       sessionDatabase;
+  private final SearchDatabase        searchDatabase;
 
   public static DatabaseFactory getInstance(Context context) {
     synchronized (lock) {
@@ -130,6 +131,10 @@ public class DatabaseFactory {
     return getInstance(context).sessionDatabase;
   }
 
+  public static SearchDatabase getSearchDatabase(Context context) {
+    return getInstance(context).searchDatabase;
+  }
+
   public static SQLiteDatabase getBackupDatabase(Context context) {
     return getInstance(context).databaseHelper.getReadableDatabase();
   }
@@ -162,6 +167,7 @@ public class DatabaseFactory {
     this.preKeyDatabase       = new OneTimePreKeyDatabase(context, databaseHelper);
     this.signedPreKeyDatabase = new SignedPreKeyDatabase(context, databaseHelper);
     this.sessionDatabase      = new SessionDatabase(context, databaseHelper);
+    this.searchDatabase       = new SearchDatabase(context, databaseHelper);
   }
 
   public void onApplicationLevelUpgrade(@NonNull Context context, @NonNull MasterSecret masterSecret,
diff --git a/src/org/thoughtcrime/securesms/database/MmsSmsDatabase.java b/src/org/thoughtcrime/securesms/database/MmsSmsDatabase.java
index f388f368eb..ef23808197 100644
--- a/src/org/thoughtcrime/securesms/database/MmsSmsDatabase.java
+++ b/src/org/thoughtcrime/securesms/database/MmsSmsDatabase.java
@@ -93,18 +93,19 @@ public class MmsSmsDatabase extends Database {
     return null;
   }
 
-  public Cursor getConversation(long threadId, long limit) {
+  public Cursor getConversation(long threadId, long offset, long limit) {
     String order     = MmsSmsColumns.NORMALIZED_DATE_RECEIVED + " DESC";
     String selection = MmsSmsColumns.THREAD_ID + " = " + threadId;
+    String limitStr  = limit > 0 || offset > 0 ? offset + ", " + limit : null;
 
-    Cursor cursor = queryTables(PROJECTION, selection, order, limit > 0 ? String.valueOf(limit) : null);
+    Cursor cursor = queryTables(PROJECTION, selection, order, limitStr);
     setNotifyConverationListeners(cursor, threadId);
 
     return cursor;
   }
 
   public Cursor getConversation(long threadId) {
-    return getConversation(threadId, 0);
+    return getConversation(threadId, 0, 0);
   }
 
   public Cursor getIdentityConflictMessagesForThread(long threadId) {
@@ -179,6 +180,26 @@ public class MmsSmsDatabase extends Database {
     return -1;
   }
 
+  /**
+   * Retrieves the position of the message with the provided timestamp in the query results you'd
+   * get from calling {@link #getConversation(long)}.
+   *
+   * Note: This could give back incorrect results in the situation where multiple messages have the
+   * same received timestamp. However, because this was designed to determine where to scroll to,
+   * you'll still wind up in about the right spot.
+   */
+  public int getMessagePositionInConversation(long threadId, long receivedTimestamp) {
+    String order     = MmsSmsColumns.NORMALIZED_DATE_RECEIVED + " DESC";
+    String selection = MmsSmsColumns.THREAD_ID + " = " + threadId + " AND " + MmsSmsColumns.NORMALIZED_DATE_RECEIVED + " > " + receivedTimestamp;
+
+    try (Cursor cursor = queryTables(new String[]{ "COUNT(*)" }, selection, order, null)) {
+      if (cursor != null && cursor.moveToFirst()) {
+        return cursor.getInt(0);
+      }
+    }
+    return -1;
+  }
+
   private Cursor queryTables(String[] projection, String selection, String order, String limit) {
     String[] mmsProjection = {MmsDatabase.DATE_SENT + " AS " + MmsSmsColumns.NORMALIZED_DATE_SENT,
                               MmsDatabase.DATE_RECEIVED + " AS " + MmsSmsColumns.NORMALIZED_DATE_RECEIVED,
diff --git a/src/org/thoughtcrime/securesms/database/SearchDatabase.java b/src/org/thoughtcrime/securesms/database/SearchDatabase.java
new file mode 100644
index 0000000000..430e257f91
--- /dev/null
+++ b/src/org/thoughtcrime/securesms/database/SearchDatabase.java
@@ -0,0 +1,89 @@
+package org.thoughtcrime.securesms.database;
+
+import android.content.Context;
+import android.support.annotation.NonNull;
+import android.util.Log;
+
+import net.sqlcipher.Cursor;
+import net.sqlcipher.database.SQLiteDatabase;
+
+import org.thoughtcrime.securesms.database.helpers.SQLCipherOpenHelper;
+
+/**
+ * Contains all databases necessary for full-text search (FTS).
+ */
+public class SearchDatabase extends Database {
+
+  public static final String SMS_FTS_TABLE_NAME = "sms_fts";
+  public static final String MMS_FTS_TABLE_NAME = "mms_fts";
+
+  public static final String ID      = "rowid";
+  public static final String BODY    = MmsSmsColumns.BODY;
+  public static final String RANK    = "rank";
+  public static final String SNIPPET = "snippet";
+
+  public static final String[] CREATE_TABLE = {
+      "CREATE VIRTUAL TABLE " + SMS_FTS_TABLE_NAME + " USING fts5(" + BODY + ", content=" + SmsDatabase.TABLE_NAME + ", content_rowid=" + SmsDatabase.ID + ");",
+
+      "CREATE TRIGGER sms_ai AFTER INSERT ON " + SmsDatabase.TABLE_NAME + " BEGIN\n" +
+          "  INSERT INTO " + SMS_FTS_TABLE_NAME + "(" + ID + ", " + BODY + ") VALUES (new." + SmsDatabase.ID + ", new." + SmsDatabase.BODY + ");\n" +
+          "END;\n",
+      "CREATE TRIGGER sms_ad AFTER DELETE ON " + SmsDatabase.TABLE_NAME + " BEGIN\n" +
+          "  INSERT INTO " + SMS_FTS_TABLE_NAME + "(" + SMS_FTS_TABLE_NAME + ", " + ID + ", " + BODY + ") VALUES('delete', old." + SmsDatabase.ID + ", old." + SmsDatabase.BODY + ");\n" +
+          "END;\n",
+      "CREATE TRIGGER sms_au AFTER UPDATE ON " + SmsDatabase.TABLE_NAME + " BEGIN\n" +
+          "  INSERT INTO " + SMS_FTS_TABLE_NAME + "(" + SMS_FTS_TABLE_NAME + ", " + ID + ", " + BODY + ") VALUES('delete', old." + SmsDatabase.ID + ", old." + SmsDatabase.BODY + ");\n" +
+          "  INSERT INTO " + SMS_FTS_TABLE_NAME + "(" + ID + ", " + BODY + ") VALUES(new." + SmsDatabase.ID + ", new." + SmsDatabase.BODY + ");\n" +
+          "END;",
+
+
+      "CREATE VIRTUAL TABLE " + MMS_FTS_TABLE_NAME + " USING fts5(" + BODY + ", content=" + MmsDatabase.TABLE_NAME + ", content_rowid=" + MmsDatabase.ID + ");",
+
+      "CREATE TRIGGER mms_ai AFTER INSERT ON " + MmsDatabase.TABLE_NAME + " BEGIN\n" +
+          "  INSERT INTO " + MMS_FTS_TABLE_NAME + "(" + ID + ", " + BODY + ") VALUES (new." + MmsDatabase.ID + ", new." + MmsDatabase.BODY + ");\n" +
+          "END;\n",
+      "CREATE TRIGGER mms_ad AFTER DELETE ON " + MmsDatabase.TABLE_NAME + " BEGIN\n" +
+          "  INSERT INTO " + MMS_FTS_TABLE_NAME + "(" + MMS_FTS_TABLE_NAME + ", " + ID + ", " + BODY + ") VALUES('delete', old." + MmsDatabase.ID + ", old." + MmsDatabase.BODY + ");\n" +
+          "END;\n",
+      "CREATE TRIGGER mms_au AFTER UPDATE ON " + MmsDatabase.TABLE_NAME + " BEGIN\n" +
+          "  INSERT INTO " + MMS_FTS_TABLE_NAME + "(" + MMS_FTS_TABLE_NAME + ", " + ID + ", " + BODY + ") VALUES('delete', old." + MmsDatabase.ID + ", old." + MmsDatabase.BODY + ");\n" +
+          "  INSERT INTO " + MMS_FTS_TABLE_NAME + "(" + ID + ", " + BODY + ") VALUES (new." + MmsDatabase.ID + ", new." + MmsDatabase.BODY + ");\n" +
+          "END;"
+  };
+
+  private static final String MESSAGES_QUERY =
+      "SELECT " +
+        MmsSmsColumns.ADDRESS + ", " +
+        "snippet(" + SMS_FTS_TABLE_NAME + ", -1, '', '', '...', 7) AS " + SNIPPET + ", " +
+        SmsDatabase.DATE_RECEIVED + " AS " + MmsSmsColumns.NORMALIZED_DATE_RECEIVED + ", " +
+        MmsSmsColumns.THREAD_ID + ", " +
+        "bm25(" + SMS_FTS_TABLE_NAME + ") AS " + RANK + " " +
+      "FROM " + SmsDatabase.TABLE_NAME + " " +
+      "INNER JOIN " + SMS_FTS_TABLE_NAME + " ON " + SMS_FTS_TABLE_NAME + "." + ID + " = " + SmsDatabase.TABLE_NAME + "." + SmsDatabase.ID + " " +
+      "WHERE " + SMS_FTS_TABLE_NAME + " MATCH ? " +
+      "UNION ALL " +
+      "SELECT " +
+        MmsSmsColumns.ADDRESS + ", " +
+        "snippet(" + MMS_FTS_TABLE_NAME + ", -1, '', '', '...', 7) AS " + SNIPPET + ", " +
+        MmsDatabase.DATE_RECEIVED + " AS " + MmsSmsColumns.NORMALIZED_DATE_RECEIVED + ", " +
+        MmsSmsColumns.THREAD_ID + ", " +
+        "bm25(" + MMS_FTS_TABLE_NAME + ") AS " + RANK + " " +
+      "FROM " + MmsDatabase.TABLE_NAME + " " +
+      "INNER JOIN " + MMS_FTS_TABLE_NAME + " ON " + MMS_FTS_TABLE_NAME + "." + ID + " = " + MmsDatabase.TABLE_NAME + "." + MmsDatabase.ID + " " +
+      "WHERE " + MMS_FTS_TABLE_NAME + " MATCH ? " +
+      "ORDER BY rank " +
+      "LIMIT 500";
+
+  public SearchDatabase(@NonNull Context context, @NonNull SQLCipherOpenHelper databaseHelper) {
+    super(context, databaseHelper);
+  }
+
+  public Cursor queryMessages(@NonNull String query) {
+    SQLiteDatabase db = databaseHelper.getReadableDatabase();
+
+    String prefixQuery = query + '*';
+
+    return db.rawQuery(MESSAGES_QUERY, new String[] { prefixQuery, prefixQuery });
+  }
+}
+
diff --git a/src/org/thoughtcrime/securesms/database/ThreadDatabase.java b/src/org/thoughtcrime/securesms/database/ThreadDatabase.java
index d91922b54f..e83fd6ae32 100644
--- a/src/org/thoughtcrime/securesms/database/ThreadDatabase.java
+++ b/src/org/thoughtcrime/securesms/database/ThreadDatabase.java
@@ -46,6 +46,7 @@ import org.thoughtcrime.securesms.util.Util;
 import org.whispersystems.libsignal.util.Pair;
 import org.whispersystems.libsignal.util.guava.Optional;
 
+import java.io.Closeable;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Set;
@@ -625,7 +626,7 @@ public class ThreadDatabase extends Database {
     public static final int INBOX_ZERO   = 4;
   }
 
-  public class Reader {
+  public class Reader implements Closeable {
 
     private final Cursor cursor;
 
@@ -692,8 +693,11 @@ public class ThreadDatabase extends Database {
       }
     }
 
+    @Override
     public void close() {
-      cursor.close();
+      if (cursor != null) {
+        cursor.close();
+      }
     }
   }
 }
diff --git a/src/org/thoughtcrime/securesms/database/helpers/SQLCipherOpenHelper.java b/src/org/thoughtcrime/securesms/database/helpers/SQLCipherOpenHelper.java
index 48aef2dc03..4338952e4c 100644
--- a/src/org/thoughtcrime/securesms/database/helpers/SQLCipherOpenHelper.java
+++ b/src/org/thoughtcrime/securesms/database/helpers/SQLCipherOpenHelper.java
@@ -4,6 +4,7 @@ package org.thoughtcrime.securesms.database.helpers;
 import android.content.ContentValues;
 import android.content.Context;
 import android.database.Cursor;
+import android.os.SystemClock;
 import android.support.annotation.NonNull;
 import android.util.Log;
 
@@ -23,6 +24,7 @@ import org.thoughtcrime.securesms.database.MmsDatabase;
 import org.thoughtcrime.securesms.database.OneTimePreKeyDatabase;
 import org.thoughtcrime.securesms.database.PushDatabase;
 import org.thoughtcrime.securesms.database.RecipientDatabase;
+import org.thoughtcrime.securesms.database.SearchDatabase;
 import org.thoughtcrime.securesms.database.SessionDatabase;
 import org.thoughtcrime.securesms.database.SignedPreKeyDatabase;
 import org.thoughtcrime.securesms.database.SmsDatabase;
@@ -45,8 +47,9 @@ public class SQLCipherOpenHelper extends SQLiteOpenHelper {
   private static final int ATTACHMENT_DIMENSIONS            = 6;
   private static final int QUOTED_REPLIES                   = 7;
   private static final int SHARED_CONTACTS                  = 8;
+  private static final int FULL_TEXT_SEARCH                 = 9;
 
-  private static final int    DATABASE_VERSION = 8;
+  private static final int    DATABASE_VERSION = 9;
   private static final String DATABASE_NAME    = "signal.db";
 
   private final Context        context;
@@ -86,6 +89,9 @@ public class SQLCipherOpenHelper extends SQLiteOpenHelper {
     db.execSQL(OneTimePreKeyDatabase.CREATE_TABLE);
     db.execSQL(SignedPreKeyDatabase.CREATE_TABLE);
     db.execSQL(SessionDatabase.CREATE_TABLE);
+    for (String sql : SearchDatabase.CREATE_TABLE) {
+      db.execSQL(sql);
+    }
 
     executeStatements(db, SmsDatabase.CREATE_INDEXS);
     executeStatements(db, MmsDatabase.CREATE_INDEXS);
@@ -182,6 +188,28 @@ public class SQLCipherOpenHelper extends SQLiteOpenHelper {
         db.execSQL("ALTER TABLE mms ADD COLUMN shared_contacts TEXT");
       }
 
+      if (oldVersion < FULL_TEXT_SEARCH) {
+        for (String sql : SearchDatabase.CREATE_TABLE) {
+          db.execSQL(sql);
+        }
+
+        Log.i(TAG, "Beginning to build search index.");
+        long start = SystemClock.elapsedRealtime();
+
+        db.execSQL("INSERT INTO " + SearchDatabase.SMS_FTS_TABLE_NAME + " (rowid, " + SearchDatabase.BODY + ") " +
+            "SELECT " + SmsDatabase.ID + " , " + SmsDatabase.BODY + " FROM " + SmsDatabase.TABLE_NAME);
+
+        long smsFinished = SystemClock.elapsedRealtime();
+        Log.i(TAG, "Indexing SMS completed in " + (smsFinished - start) + " ms");
+
+        db.execSQL("INSERT INTO " + SearchDatabase.MMS_FTS_TABLE_NAME + " (rowid, " + SearchDatabase.BODY + ") " +
+            "SELECT " + MmsDatabase.ID + " , " + MmsDatabase.BODY + " FROM " + MmsDatabase.TABLE_NAME);
+
+        long mmsFinished = SystemClock.elapsedRealtime();
+        Log.i(TAG, "Indexing MMS completed in " + (mmsFinished - smsFinished) + " ms");
+        Log.i(TAG, "Indexing finished. Total time: " + (mmsFinished - start) + " ms");
+      }
+
       db.setTransactionSuccessful();
     } finally {
       db.endTransaction();
diff --git a/src/org/thoughtcrime/securesms/database/loaders/ConversationLoader.java b/src/org/thoughtcrime/securesms/database/loaders/ConversationLoader.java
index 3f8866b81d..fe6a2af0e7 100644
--- a/src/org/thoughtcrime/securesms/database/loaders/ConversationLoader.java
+++ b/src/org/thoughtcrime/securesms/database/loaders/ConversationLoader.java
@@ -9,13 +9,15 @@ import org.whispersystems.libsignal.util.Pair;
 
 public class ConversationLoader extends AbstractCursorLoader {
   private final long    threadId;
-  private       long    limit;
+  private       int     offset;
+  private       int     limit;
   private       long    lastSeen;
   private       boolean hasSent;
 
-  public ConversationLoader(Context context, long threadId, long limit, long lastSeen) {
+  public ConversationLoader(Context context, long threadId, int offset, int limit, long lastSeen) {
     super(context);
     this.threadId = threadId;
+    this.offset   = offset;
     this.limit    = limit;
     this.lastSeen = lastSeen;
     this.hasSent  = true;
@@ -25,6 +27,14 @@ public class ConversationLoader extends AbstractCursorLoader {
     return limit > 0;
   }
 
+  public boolean hasOffset() {
+    return offset > 0;
+  }
+
+  public int getOffset() {
+    return offset;
+  }
+
   public long getLastSeen() {
     return lastSeen;
   }
@@ -43,6 +53,6 @@ public class ConversationLoader extends AbstractCursorLoader {
       this.lastSeen = lastSeenAndHasSent.first();
     }
 
-    return DatabaseFactory.getMmsSmsDatabase(context).getConversation(threadId, limit);
+    return DatabaseFactory.getMmsSmsDatabase(context).getConversation(threadId, offset, limit);
   }
 }
diff --git a/src/org/thoughtcrime/securesms/search/SearchFragment.java b/src/org/thoughtcrime/securesms/search/SearchFragment.java
new file mode 100644
index 0000000000..3b7930321e
--- /dev/null
+++ b/src/org/thoughtcrime/securesms/search/SearchFragment.java
@@ -0,0 +1,178 @@
+package org.thoughtcrime.securesms.search;
+
+import android.annotation.SuppressLint;
+import android.arch.lifecycle.ViewModelProviders;
+import android.content.Intent;
+import android.os.AsyncTask;
+import android.os.Bundle;
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.support.v4.app.Fragment;
+import android.support.v7.widget.LinearLayoutManager;
+import android.support.v7.widget.RecyclerView;
+import android.text.TextUtils;
+import android.util.Log;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.TextView;
+
+import org.thoughtcrime.securesms.ConversationActivity;
+import org.thoughtcrime.securesms.ConversationListActivity;
+import org.thoughtcrime.securesms.R;
+import org.thoughtcrime.securesms.contacts.ContactAccessor;
+import org.thoughtcrime.securesms.database.DatabaseFactory;
+import org.thoughtcrime.securesms.database.ThreadDatabase;
+import org.thoughtcrime.securesms.database.model.ThreadRecord;
+import org.thoughtcrime.securesms.mms.GlideApp;
+import org.thoughtcrime.securesms.recipients.Recipient;
+import org.thoughtcrime.securesms.search.model.MessageResult;
+import org.thoughtcrime.securesms.search.model.SearchResult;
+import org.thoughtcrime.securesms.util.StickyHeaderDecoration;
+
+import java.util.Locale;
+import java.util.concurrent.Executors;
+
+/**
+ * A fragment that is displayed to do full-text search of messages, groups, and contacts.
+ */
+public class SearchFragment extends Fragment implements SearchListAdapter.EventListener {
+
+  public static final String TAG          = "SearchFragment";
+  public static final String EXTRA_LOCALE = "locale";
+
+  private TextView     noResultsView;
+  private RecyclerView listView;
+
+  private SearchViewModel   viewModel;
+  private SearchListAdapter listAdapter;
+  private String            pendingQuery;
+  private Locale            locale;
+
+  public static SearchFragment newInstance(@NonNull Locale locale) {
+    Bundle args = new Bundle();
+    args.putSerializable(EXTRA_LOCALE, locale);
+
+    SearchFragment fragment = new SearchFragment();
+    fragment.setArguments(args);
+
+    return fragment;
+  }
+
+  @Override
+  public void onCreate(@Nullable Bundle savedInstanceState) {
+    super.onCreate(savedInstanceState);
+
+    this.locale = (Locale) getArguments().getSerializable(EXTRA_LOCALE);
+
+    SearchRepository searchRepository = new SearchRepository(getContext(),
+                                                             DatabaseFactory.getSearchDatabase(getContext()),
+                                                             DatabaseFactory.getContactsDatabase(getContext()),
+                                                             DatabaseFactory.getThreadDatabase(getContext()),
+                                                             ContactAccessor.getInstance(),
+                                                             Executors.newSingleThreadExecutor());
+    viewModel = ViewModelProviders.of(this, new SearchViewModel.Factory(searchRepository)).get(SearchViewModel.class);
+
+    if (pendingQuery != null) {
+      viewModel.updateQuery(pendingQuery);
+      pendingQuery = null;
+    }
+  }
+
+  @Nullable
+  @Override
+  public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
+    return inflater.inflate(R.layout.fragment_search, container, false);
+  }
+
+  @Override
+  public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
+    noResultsView = view.findViewById(R.id.search_no_results);
+    listView      = view.findViewById(R.id.search_list);
+
+    listAdapter = new SearchListAdapter(GlideApp.with(this), this, locale);
+    listView.setAdapter(listAdapter);
+    listView.setLayoutManager(new LinearLayoutManager(getContext()));
+    listView.addItemDecoration(new StickyHeaderDecoration(listAdapter, false, false));
+  }
+
+  @Override
+  public void onStart() {
+    super.onStart();
+    viewModel.getSearchResult().observe(this, result -> {
+      result = result != null ? result : SearchResult.EMPTY;
+
+      listAdapter.updateResults(result);
+
+      if (result.isEmpty()) {
+        if (TextUtils.isEmpty(viewModel.getLastQuery().trim())) {
+          noResultsView.setVisibility(View.GONE);
+        } else {
+          noResultsView.setVisibility(View.VISIBLE);
+          noResultsView.setText(getString(R.string.SearchFragment_no_results, viewModel.getLastQuery()));
+        }
+      } else {
+        noResultsView.setVisibility(View.VISIBLE);
+        noResultsView.setText("");
+      }
+    });
+  }
+
+  @Override
+  public void onConversationClicked(@NonNull ThreadRecord threadRecord) {
+    ConversationListActivity conversationList = (ConversationListActivity) getActivity();
+
+    if (conversationList != null) {
+      conversationList.onCreateConversation(threadRecord.getThreadId(),
+                                            threadRecord.getRecipient(),
+                                            threadRecord.getDistributionType(),
+                                            threadRecord.getLastSeen());
+    }
+  }
+
+  @Override
+  public void onContactClicked(@NonNull Recipient contact) {
+    Intent intent = new Intent(getContext(), ConversationActivity.class);
+    intent.putExtra(ConversationActivity.ADDRESS_EXTRA, contact.getAddress());
+
+    long existingThread = DatabaseFactory.getThreadDatabase(getContext()).getThreadIdIfExistsFor(contact);
+
+    intent.putExtra(ConversationActivity.THREAD_ID_EXTRA, existingThread);
+    intent.putExtra(ConversationActivity.DISTRIBUTION_TYPE_EXTRA, ThreadDatabase.DistributionTypes.DEFAULT);
+    startActivity(intent);
+  }
+
+  @SuppressLint("StaticFieldLeak")
+  @Override
+  public void onMessageClicked(@NonNull MessageResult message) {
+    new AsyncTask<Void, Void, Integer>() {
+      @Override
+      protected Integer doInBackground(Void... voids) {
+        int  startingPosition = DatabaseFactory.getMmsSmsDatabase(getContext()).getMessagePositionInConversation(message.threadId, message.receivedTimestampMs);
+        startingPosition = Math.max(0, startingPosition);
+
+        return startingPosition;
+      }
+
+      @Override
+      protected void onPostExecute(Integer startingPosition) {
+        ConversationListActivity conversationList = (ConversationListActivity) getActivity();
+        if (conversationList != null) {
+          conversationList.openConversation(message.threadId,
+                                            message.recipient,
+                                            ThreadDatabase.DistributionTypes.DEFAULT,
+                                            -1,
+                                            startingPosition);
+        }
+      }
+    }.execute();
+  }
+
+  public void updateSearchQuery(@NonNull String query) {
+    if (viewModel != null) {
+      viewModel.updateQuery(query);
+    } else {
+      pendingQuery = query;
+    }
+  }
+}
diff --git a/src/org/thoughtcrime/securesms/search/SearchListAdapter.java b/src/org/thoughtcrime/securesms/search/SearchListAdapter.java
new file mode 100644
index 0000000000..a4d4d681ac
--- /dev/null
+++ b/src/org/thoughtcrime/securesms/search/SearchListAdapter.java
@@ -0,0 +1,219 @@
+package org.thoughtcrime.securesms.search;
+
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.support.v7.widget.RecyclerView;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.TextView;
+
+import org.thoughtcrime.securesms.ConversationListItem;
+import org.thoughtcrime.securesms.R;
+import org.thoughtcrime.securesms.database.model.ThreadRecord;
+import org.thoughtcrime.securesms.mms.GlideRequests;
+import org.thoughtcrime.securesms.recipients.Recipient;
+import org.thoughtcrime.securesms.search.model.MessageResult;
+import org.thoughtcrime.securesms.search.model.SearchResult;
+import org.thoughtcrime.securesms.util.StickyHeaderDecoration;
+
+import java.util.Collections;
+import java.util.Locale;
+
+class SearchListAdapter extends    RecyclerView.Adapter<SearchListAdapter.SearchResultViewHolder>
+                        implements StickyHeaderDecoration.StickyHeaderAdapter<SearchListAdapter.HeaderViewHolder>
+{
+  private static final int TYPE_CONVERSATIONS = 1;
+  private static final int TYPE_CONTACTS      = 2;
+  private static final int TYPE_MESSAGES      = 3;
+
+  private final GlideRequests glideRequests;
+  private final EventListener eventListener;
+  private final Locale        locale;
+
+  @NonNull
+  private SearchResult searchResult = SearchResult.EMPTY;
+
+  SearchListAdapter(@NonNull GlideRequests glideRequests,
+                    @NonNull EventListener eventListener,
+                    @NonNull Locale        locale)
+  {
+    this.glideRequests = glideRequests;
+    this.eventListener = eventListener;
+    this.locale        = locale;
+  }
+
+  @NonNull
+  @Override
+  public SearchResultViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
+    return new SearchResultViewHolder(LayoutInflater.from(parent.getContext())
+                                                    .inflate(R.layout.conversation_list_item_view, parent, false));
+  }
+
+  @Override
+  public void onBindViewHolder(@NonNull SearchResultViewHolder holder, int position) {
+    ThreadRecord conversationResult = getConversationResult(position);
+
+    if (conversationResult != null) {
+      holder.bind(conversationResult, glideRequests, eventListener, locale, searchResult.getQuery());
+      return;
+    }
+
+    Recipient contactResult = getContactResult(position);
+
+    if (contactResult != null) {
+      holder.bind(contactResult, glideRequests, eventListener, locale, searchResult.getQuery());
+      return;
+    }
+
+    MessageResult messageResult = getMessageResult(position);
+
+    if (messageResult != null) {
+      holder.bind(messageResult, glideRequests, eventListener, locale, searchResult.getQuery());
+    }
+  }
+
+  @Override
+  public void onViewRecycled(SearchResultViewHolder holder) {
+    holder.recycle();
+  }
+
+  @Override
+  public int getItemCount() {
+    return searchResult.size();
+  }
+
+  @Override
+  public long getHeaderId(int position) {
+    if (getConversationResult(position) != null) {
+      return TYPE_CONVERSATIONS;
+    } else if (getContactResult(position) != null) {
+      return TYPE_CONTACTS;
+    } else {
+      return TYPE_MESSAGES;
+    }
+  }
+
+  @Override
+  public HeaderViewHolder onCreateHeaderViewHolder(ViewGroup parent) {
+    return new HeaderViewHolder(LayoutInflater.from(parent.getContext())
+                                              .inflate(R.layout.header_search_result, parent, false));
+  }
+
+  @Override
+  public void onBindHeaderViewHolder(HeaderViewHolder viewHolder, int position) {
+    viewHolder.bind((int) getHeaderId(position));
+  }
+
+  void updateResults(@NonNull SearchResult result) {
+    this.searchResult = result;
+    notifyDataSetChanged();
+  }
+
+  @Nullable
+  private ThreadRecord getConversationResult(int position) {
+    if (position < searchResult.getConversations().size()) {
+      return searchResult.getConversations().get(position);
+    }
+    return null;
+  }
+
+  @Nullable
+  private Recipient getContactResult(int position) {
+    if (position >= getFirstContactIndex() && position < getFirstMessageIndex()) {
+      return searchResult.getContacts().get(position - getFirstContactIndex());
+    }
+    return null;
+  }
+
+  @Nullable
+  private MessageResult getMessageResult(int position) {
+    if (position >= getFirstMessageIndex() && position < searchResult.size()) {
+      return searchResult.getMessages().get(position - getFirstMessageIndex());
+    }
+    return null;
+  }
+
+  private int getFirstContactIndex() {
+    return searchResult.getConversations().size();
+  }
+
+  private int getFirstMessageIndex() {
+    return getFirstContactIndex() + searchResult.getContacts().size();
+  }
+
+  public interface EventListener {
+    void onConversationClicked(@NonNull ThreadRecord threadRecord);
+    void onContactClicked(@NonNull Recipient contact);
+    void onMessageClicked(@NonNull MessageResult message);
+  }
+
+  static class SearchResultViewHolder extends RecyclerView.ViewHolder {
+
+    private final ConversationListItem root;
+
+    SearchResultViewHolder(View itemView) {
+      super(itemView);
+      root = (ConversationListItem) itemView;
+    }
+
+    void bind(@NonNull  ThreadRecord  conversationResult,
+              @NonNull  GlideRequests glideRequests,
+              @NonNull  EventListener eventListener,
+              @NonNull  Locale        locale,
+              @Nullable String        query)
+    {
+      root.bind(conversationResult, glideRequests, locale, Collections.emptySet(), false, query);
+      root.setOnClickListener(view -> eventListener.onConversationClicked(conversationResult));
+    }
+
+    void bind(@NonNull  Recipient     contactResult,
+              @NonNull  GlideRequests glideRequests,
+              @NonNull  EventListener eventListener,
+              @NonNull  Locale        locale,
+              @Nullable String        query)
+    {
+      root.bind(contactResult, glideRequests, locale, query);
+      root.setOnClickListener(view -> eventListener.onContactClicked(contactResult));
+    }
+
+    void bind(@NonNull  MessageResult messageResult,
+              @NonNull  GlideRequests glideRequests,
+              @NonNull  EventListener eventListener,
+              @NonNull  Locale        locale,
+              @Nullable String        query)
+    {
+      root.bind(messageResult, glideRequests, locale, query);
+      root.setOnClickListener(view -> eventListener.onMessageClicked(messageResult));
+    }
+
+    void recycle() {
+      root.unbind();
+      root.setOnClickListener(null);
+    }
+  }
+
+  public static class HeaderViewHolder extends RecyclerView.ViewHolder {
+
+    private TextView titleView;
+
+    public HeaderViewHolder(View itemView) {
+      super(itemView);
+      titleView = (TextView) itemView;
+    }
+
+    public void bind(int headerType) {
+      switch (headerType) {
+        case TYPE_CONVERSATIONS:
+          titleView.setText(R.string.SearchFragment_header_conversations);
+          break;
+        case TYPE_CONTACTS:
+          titleView.setText(R.string.SearchFragment_header_contacts);
+          break;
+        case TYPE_MESSAGES:
+          titleView.setText(R.string.SearchFragment_header_messages);
+          break;
+      }
+    }
+  }
+}
diff --git a/src/org/thoughtcrime/securesms/search/SearchRepository.java b/src/org/thoughtcrime/securesms/search/SearchRepository.java
new file mode 100644
index 0000000000..fb4d0f344d
--- /dev/null
+++ b/src/org/thoughtcrime/securesms/search/SearchRepository.java
@@ -0,0 +1,188 @@
+package org.thoughtcrime.securesms.search;
+
+import android.Manifest;
+import android.content.Context;
+import android.database.Cursor;
+import android.database.DatabaseUtils;
+import android.database.MergeCursor;
+import android.support.annotation.NonNull;
+import android.text.TextUtils;
+
+import com.annimon.stream.Stream;
+
+
+import org.thoughtcrime.securesms.contacts.ContactAccessor;
+import org.thoughtcrime.securesms.contacts.ContactsDatabase;
+import org.thoughtcrime.securesms.database.Address;
+import org.thoughtcrime.securesms.database.CursorList;
+import org.thoughtcrime.securesms.database.MmsSmsColumns;
+import org.thoughtcrime.securesms.database.SearchDatabase;
+import org.thoughtcrime.securesms.database.ThreadDatabase;
+import org.thoughtcrime.securesms.database.model.ThreadRecord;
+import org.thoughtcrime.securesms.permissions.Permissions;
+import org.thoughtcrime.securesms.recipients.Recipient;
+import org.thoughtcrime.securesms.search.model.MessageResult;
+import org.thoughtcrime.securesms.search.model.SearchResult;
+
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.Executor;
+
+/**
+ * Manages data retrieval for search.
+ */
+class SearchRepository {
+
+  private static final Set<Character> BANNED_CHARACTERS = new HashSet<>();
+  static {
+    // Several ranges of invalid ASCII characters
+    for (int i = 33; i <= 47; i++) {
+      BANNED_CHARACTERS.add((char) i);
+    }
+    for (int i = 58; i <= 64; i++) {
+      BANNED_CHARACTERS.add((char) i);
+    }
+    for (int i = 91; i <= 96; i++) {
+      BANNED_CHARACTERS.add((char) i);
+    }
+    for (int i = 123; i <= 126; i++) {
+      BANNED_CHARACTERS.add((char) i);
+    }
+  }
+
+  private final Context          context;
+  private final SearchDatabase   searchDatabase;
+  private final ContactsDatabase contactsDatabase;
+  private final ThreadDatabase   threadDatabase;
+  private final ContactAccessor  contactAccessor;
+  private final Executor         executor;
+
+  SearchRepository(@NonNull Context          context,
+                   @NonNull SearchDatabase   searchDatabase,
+                   @NonNull ContactsDatabase contactsDatabase,
+                   @NonNull ThreadDatabase   threadDatabase,
+                   @NonNull ContactAccessor  contactAccessor,
+                   @NonNull Executor         executor)
+  {
+    this.context          = context.getApplicationContext();
+    this.searchDatabase   = searchDatabase;
+    this.contactsDatabase = contactsDatabase;
+    this.threadDatabase   = threadDatabase;
+    this.contactAccessor  = contactAccessor;
+    this.executor         = executor;
+  }
+
+  void query(@NonNull String query, @NonNull Callback callback) {
+    if (TextUtils.isEmpty(query)) {
+      callback.onResult(SearchResult.EMPTY);
+      return;
+    }
+
+    executor.execute(() -> {
+      String                    cleanQuery    = sanitizeQuery(query);
+      CursorList<Recipient>     contacts      = queryContacts(cleanQuery);
+      CursorList<ThreadRecord>  conversations = queryConversations(cleanQuery);
+      CursorList<MessageResult> messages      = queryMessages(cleanQuery);
+
+      callback.onResult(new SearchResult(cleanQuery, contacts, conversations, messages));
+    });
+  }
+
+  private CursorList<Recipient> queryContacts(String query) {
+    if (!Permissions.hasAny(context, Manifest.permission.READ_CONTACTS, Manifest.permission.WRITE_CONTACTS)) {
+      return CursorList.emptyList();
+    }
+
+    Cursor      textSecureContacts = contactsDatabase.queryTextSecureContacts(query);
+    Cursor      systemContacts     = contactsDatabase.querySystemContacts(query);
+    MergeCursor contacts           = new MergeCursor(new Cursor[]{ textSecureContacts, systemContacts });
+
+    return new CursorList<>(contacts, new RecipientModelBuilder(context));
+  }
+
+  private CursorList<ThreadRecord> queryConversations(@NonNull String query) {
+    List<String>  numbers   = contactAccessor.getNumbersForThreadSearchFilter(context, query);
+    List<Address> addresses = Stream.of(numbers).map(number -> Address.fromExternal(context, number)).toList();
+
+    Cursor conversations = threadDatabase.getFilteredConversationList(addresses);
+    return conversations != null ? new CursorList<>(conversations, new ThreadModelBuilder(threadDatabase))
+                                 : CursorList.emptyList();
+  }
+
+  private CursorList<MessageResult> queryMessages(@NonNull String query) {
+    Cursor messages = searchDatabase.queryMessages(query);
+    return messages != null ? new CursorList<>(messages, new MessageModelBuilder(context))
+                            : CursorList.emptyList();
+  }
+
+  /**
+   * Unfortunately {@link DatabaseUtils#sqlEscapeString(String)} is not sufficient for our purposes.
+   * MATCH queries have a separate format of their own that disallow most "special" characters.
+   */
+  private String sanitizeQuery(@NonNull String query) {
+    StringBuilder out = new StringBuilder();
+
+    for (int i = 0; i < query.length(); i++) {
+      char c = query.charAt(i);
+      if (!BANNED_CHARACTERS.contains(c)) {
+        out.append(c);
+      }
+    }
+
+    return out.toString();
+  }
+
+  private static class RecipientModelBuilder implements CursorList.ModelBuilder<Recipient> {
+
+    private final Context context;
+
+    RecipientModelBuilder(@NonNull Context context) {
+      this.context = context;
+    }
+
+    @Override
+    public Recipient build(@NonNull Cursor cursor) {
+      Address address = Address.fromExternal(context, cursor.getString(1));
+      return Recipient.from(context, address, false);
+    }
+  }
+
+  private static class ThreadModelBuilder implements CursorList.ModelBuilder<ThreadRecord> {
+
+    private final ThreadDatabase threadDatabase;
+
+    ThreadModelBuilder(@NonNull ThreadDatabase threadDatabase) {
+      this.threadDatabase = threadDatabase;
+    }
+
+    @Override
+    public ThreadRecord build(@NonNull Cursor cursor) {
+      return threadDatabase.readerFor(cursor).getCurrent();
+    }
+  }
+
+  private static class MessageModelBuilder implements CursorList.ModelBuilder<MessageResult> {
+
+    private final Context context;
+
+    MessageModelBuilder(@NonNull Context context) {
+      this.context = context;
+    }
+
+    @Override
+    public MessageResult build(@NonNull Cursor cursor) {
+      Address   address    = Address.fromSerialized(cursor.getString(0));
+      Recipient recipient  = Recipient.from(context, address, false);
+      String    body       = cursor.getString(cursor.getColumnIndexOrThrow(SearchDatabase.SNIPPET));
+      long      receivedMs = cursor.getLong(cursor.getColumnIndexOrThrow(MmsSmsColumns.NORMALIZED_DATE_RECEIVED));
+      long      threadId   = cursor.getLong(cursor.getColumnIndexOrThrow(MmsSmsColumns.THREAD_ID));
+
+      return new MessageResult(recipient, body, threadId, receivedMs);
+    }
+  }
+
+  public interface Callback {
+    void onResult(@NonNull SearchResult result);
+  }
+}
diff --git a/src/org/thoughtcrime/securesms/search/SearchViewModel.java b/src/org/thoughtcrime/securesms/search/SearchViewModel.java
new file mode 100644
index 0000000000..360d516460
--- /dev/null
+++ b/src/org/thoughtcrime/securesms/search/SearchViewModel.java
@@ -0,0 +1,89 @@
+package org.thoughtcrime.securesms.search;
+
+import android.arch.lifecycle.LiveData;
+import android.arch.lifecycle.MutableLiveData;
+import android.arch.lifecycle.ViewModel;
+import android.arch.lifecycle.ViewModelProvider;
+import android.support.annotation.NonNull;
+
+import org.thoughtcrime.securesms.search.model.SearchResult;
+import org.thoughtcrime.securesms.util.Debouncer;
+
+/**
+ * A {@link ViewModel} for handling all the business logic and interactions that take place inside
+ * of the {@link SearchFragment}.
+ *
+ * This class should be view- and Android-agnostic, and therefore should contain no references to
+ * things like {@link android.content.Context}, {@link android.view.View},
+ * {@link android.support.v4.app.Fragment}, etc.
+ */
+class SearchViewModel extends ViewModel {
+
+  private final ClosingLiveData  searchResult;
+  private final SearchRepository searchRepository;
+  private final Debouncer        debouncer;
+
+  private String lastQuery;
+
+  SearchViewModel(@NonNull SearchRepository searchRepository) {
+    this.searchResult     = new ClosingLiveData();
+    this.searchRepository = searchRepository;
+    this.debouncer        = new Debouncer(500);
+  }
+
+  LiveData<SearchResult> getSearchResult() {
+    return searchResult;
+  }
+
+  void updateQuery(String query) {
+    lastQuery = query;
+    debouncer.publish(() -> searchRepository.query(query, searchResult::postValue));
+  }
+
+  @NonNull
+  String getLastQuery() {
+    return lastQuery == null ? "" : lastQuery;
+  }
+
+  @Override
+  protected void onCleared() {
+    searchResult.close();
+  }
+
+  /**
+   * Ensures that the previous {@link SearchResult} is always closed whenever we set a new one.
+   */
+  private static class ClosingLiveData extends MutableLiveData<SearchResult> {
+
+    @Override
+    public void setValue(SearchResult value) {
+      SearchResult previous = getValue();
+      if (previous != null) {
+        previous.close();
+      }
+      super.setValue(value);
+    }
+
+    public void close() {
+      SearchResult value = getValue();
+      if (value != null) {
+        value.close();
+      }
+    }
+  }
+
+  public static class Factory extends ViewModelProvider.NewInstanceFactory {
+
+    private final SearchRepository searchRepository;
+
+    public Factory(@NonNull SearchRepository searchRepository) {
+      this.searchRepository = searchRepository;
+    }
+
+    @NonNull
+    @Override
+    public <T extends ViewModel> T create(@NonNull Class<T> modelClass) {
+      return modelClass.cast(new SearchViewModel(searchRepository));
+    }
+  }
+}
diff --git a/src/org/thoughtcrime/securesms/search/model/MessageResult.java b/src/org/thoughtcrime/securesms/search/model/MessageResult.java
new file mode 100644
index 0000000000..c47d73e11a
--- /dev/null
+++ b/src/org/thoughtcrime/securesms/search/model/MessageResult.java
@@ -0,0 +1,27 @@
+package org.thoughtcrime.securesms.search.model;
+
+import android.support.annotation.NonNull;
+
+import org.thoughtcrime.securesms.recipients.Recipient;
+
+/**
+ * Represents a search result for a message.
+ */
+public class MessageResult {
+
+  public final Recipient recipient;
+  public final String    bodySnippet;
+  public final long      threadId;
+  public final long      receivedTimestampMs;
+
+  public MessageResult(@NonNull Recipient recipient,
+                       @NonNull String bodySnippet,
+                       long threadId,
+                       long receivedTimestampMs)
+  {
+    this.recipient           = recipient;
+    this.bodySnippet         = bodySnippet;
+    this.threadId            = threadId;
+    this.receivedTimestampMs = receivedTimestampMs;
+  }
+}
diff --git a/src/org/thoughtcrime/securesms/search/model/SearchResult.java b/src/org/thoughtcrime/securesms/search/model/SearchResult.java
new file mode 100644
index 0000000000..e13f4b5090
--- /dev/null
+++ b/src/org/thoughtcrime/securesms/search/model/SearchResult.java
@@ -0,0 +1,64 @@
+package org.thoughtcrime.securesms.search.model;
+
+import android.support.annotation.NonNull;
+
+import org.thoughtcrime.securesms.database.CursorList;
+import org.thoughtcrime.securesms.database.model.ThreadRecord;
+import org.thoughtcrime.securesms.recipients.Recipient;
+
+import java.util.List;
+
+/**
+ * Represents an all-encompassing search result that can contain various result for different
+ * subcategories.
+ */
+public class SearchResult {
+
+  public static final SearchResult EMPTY = new SearchResult("", CursorList.emptyList(), CursorList.emptyList(), CursorList.emptyList());
+
+  private final String                    query;
+  private final CursorList<Recipient>     contacts;
+  private final CursorList<ThreadRecord>  conversations;
+  private final CursorList<MessageResult> messages;
+
+  public SearchResult(@NonNull String                    query,
+                      @NonNull CursorList<Recipient>     contacts,
+                      @NonNull CursorList<ThreadRecord>  conversations,
+                      @NonNull CursorList<MessageResult> messages)
+  {
+    this.query         = query;
+    this.contacts      = contacts;
+    this.conversations = conversations;
+    this.messages      = messages;
+  }
+
+  public List<Recipient> getContacts() {
+    return contacts;
+  }
+
+  public List<ThreadRecord> getConversations() {
+    return conversations;
+  }
+
+  public List<MessageResult> getMessages() {
+    return messages;
+  }
+
+  public String getQuery() {
+    return query;
+  }
+
+  public int size() {
+    return contacts.size() + conversations.size() + messages.size();
+  }
+
+  public boolean isEmpty() {
+    return size() == 0;
+  }
+
+  public void close() {
+    contacts.close();
+    conversations.close();
+    messages.close();
+  }
+}
diff --git a/src/org/thoughtcrime/securesms/util/Debouncer.java b/src/org/thoughtcrime/securesms/util/Debouncer.java
new file mode 100644
index 0000000000..d02fe8d05d
--- /dev/null
+++ b/src/org/thoughtcrime/securesms/util/Debouncer.java
@@ -0,0 +1,32 @@
+package org.thoughtcrime.securesms.util;
+
+import android.os.Handler;
+
+/**
+ * A class that will throttle the number of runnables executed to be at most once every specified
+ * interval.
+ *
+ * Useful for performing actions in response to rapid user input, such as inputting text, where you
+ * don't necessarily want to perform an action after <em>every</em> input.
+ *
+ * See http://rxmarbles.com/#debounce
+ */
+public class Debouncer {
+
+  private final Handler handler;
+  private final long    threshold;
+
+  /**
+   * @param threshold Only one runnable will be executed via {@link #publish(Runnable)} every
+   *                  {@code threshold} milliseconds.
+   */
+  public Debouncer(long threshold) {
+    this.handler   = new Handler();
+    this.threshold = threshold;
+  }
+
+  public void publish(Runnable runnable) {
+    handler.removeCallbacksAndMessages(null);
+    handler.postDelayed(runnable, threshold);
+  }
+}