/**
 * Copyright (C) 2011 Whisper Systems
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.thoughtcrime.securesms.database;

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteStatement;
import android.net.Uri;
import android.util.Log;

import org.thoughtcrime.securesms.crypto.MasterCipher;
import org.thoughtcrime.securesms.crypto.MasterSecret;
import org.thoughtcrime.securesms.protocol.Prefix;
import org.thoughtcrime.securesms.recipients.RecipientFactory;
import org.thoughtcrime.securesms.recipients.RecipientFormattingException;
import org.thoughtcrime.securesms.recipients.Recipients;

import java.util.StringTokenizer;

public class SmsMigrator {

  private static void addEncryptedStringToStatement(Context context, SQLiteStatement statement,
                                                    Cursor cursor, MasterSecret masterSecret,
                                                    int index, String key)
  {
    int columnIndex = cursor.getColumnIndexOrThrow(key);

    if (cursor.isNull(columnIndex)) {
      statement.bindNull(index);
    } else {
      statement.bindString(index, encryptIfNecessary(context, masterSecret, cursor.getString(columnIndex)));
    }
  }

  private static void addStringToStatement(SQLiteStatement statement, Cursor cursor,
                                           int index, String key)
  {
    int columnIndex = cursor.getColumnIndexOrThrow(key);

    if (cursor.isNull(columnIndex)) {
      statement.bindNull(index);
    } else {
      statement.bindString(index, cursor.getString(columnIndex));
    }
  }

  private static void addIntToStatement(SQLiteStatement statement, Cursor cursor,
                                        int index, String key)
  {
    int columnIndex = cursor.getColumnIndexOrThrow(key);

    if (cursor.isNull(columnIndex)) {
      statement.bindNull(index);
    } else {
      statement.bindLong(index, cursor.getLong(columnIndex));
    }
  }

  private static void getContentValuesForRow(Context context, MasterSecret masterSecret,
                                             Cursor cursor, long threadId,
                                             SQLiteStatement statement)
  {
    addStringToStatement(statement, cursor, 1, SmsDatabase.ADDRESS);
    addIntToStatement(statement, cursor, 2, SmsDatabase.PERSON);
    addIntToStatement(statement, cursor, 3, SmsDatabase.DATE);
    addIntToStatement(statement, cursor, 4, SmsDatabase.PROTOCOL);
    addIntToStatement(statement, cursor, 5, SmsDatabase.READ);
    addIntToStatement(statement, cursor, 6, SmsDatabase.STATUS);
    addIntToStatement(statement, cursor, 7, SmsDatabase.TYPE);
    addIntToStatement(statement, cursor, 8, SmsDatabase.REPLY_PATH_PRESENT);
    addStringToStatement(statement, cursor, 9, SmsDatabase.SUBJECT);
    addEncryptedStringToStatement(context, statement, cursor, masterSecret, 10, SmsDatabase.BODY);
    addStringToStatement(statement, cursor, 11, SmsDatabase.SERVICE_CENTER);

    statement.bindLong(12, threadId);
  }

  private static String getTheirCanonicalAddress(Context context, String theirRecipientId) {
    Uri uri       = Uri.parse("content://mms-sms/canonical-address/" + theirRecipientId);
    Cursor cursor = null;

    try {
      cursor = context.getContentResolver().query(uri, null, null, null, null);

      if (cursor != null && cursor.moveToFirst()) {
        return cursor.getString(0);
      } else {
        return null;
      }

    } finally {
      if (cursor != null)
        cursor.close();
    }
  }

  private static Recipients getOurRecipients(Context context, String theirRecipients) {
    StringTokenizer tokenizer = new StringTokenizer(theirRecipients.trim(), " ");
    StringBuilder sb          = new StringBuilder();

    while (tokenizer.hasMoreTokens()) {
      String theirRecipientId = tokenizer.nextToken();
      String address          = getTheirCanonicalAddress(context, theirRecipientId);

      if (address == null)
        continue;

      if (sb.length() != 0)
        sb.append(',');

      sb.append(address);
    }

    try {
      if (sb.length() == 0) return null;
      else                  return RecipientFactory.getRecipientsFromString(context, sb.toString());
    } catch (RecipientFormattingException rfe) {
      Log.w("SmsMigrator", rfe);
      return null;
    }
  }

  private static String encryptIfNecessary(Context context,
                                           MasterSecret masterSecret,
                                           String body)
  {
    if (!body.startsWith(Prefix.SYMMETRIC_ENCRYPT) && !body.startsWith(Prefix.ASYMMETRIC_ENCRYPT)) {
      MasterCipher masterCipher = new MasterCipher(masterSecret);
      return Prefix.SYMMETRIC_ENCRYPT + masterCipher.encryptBody(body);
    }

    return body;
  }

  private static void migrateConversation(Context context, MasterSecret masterSecret,
                                          SmsMigrationProgressListener listener,
                                          int primaryProgress,
                                          long theirThreadId, long ourThreadId)
  {
    SmsDatabase ourSmsDatabase = DatabaseFactory.getSmsDatabase(context);
    Cursor cursor              = null;

    try {
      Uri uri                    = Uri.parse("content://sms/conversations/" + theirThreadId);
      cursor                     = context.getContentResolver().query(uri, null, null, null, null);
      SQLiteDatabase transaction = ourSmsDatabase.beginTransaction();
      SQLiteStatement statement  = ourSmsDatabase.createInsertStatement(transaction);

      while (cursor != null && cursor.moveToNext()) {
        getContentValuesForRow(context, masterSecret, cursor, ourThreadId, statement);
        statement.execute();

        double position = cursor.getPosition();
        double count    = cursor.getCount();
        double progress = position / count;

        listener.progressUpdate(primaryProgress, (int)(progress * 10000));
      }

      ourSmsDatabase.endTransaction(transaction);
      DatabaseFactory.getThreadDatabase(context).update(ourThreadId);
      DatabaseFactory.getThreadDatabase(context).notifyConversationListeners(ourThreadId);

    } finally {
      if (cursor != null)
        cursor.close();
    }
  }

  public static void migrateDatabase(Context context,
                                     MasterSecret masterSecret,
                                     SmsMigrationProgressListener listener)
  {
    if (context.getSharedPreferences("SecureSMS", Context.MODE_PRIVATE).getBoolean("migrated", false))
      return;

    ThreadDatabase threadDatabase = DatabaseFactory.getThreadDatabase(context);
    Cursor cursor                 = null;
    int primaryProgress           = 0;

    try {
      Uri threadListUri = Uri.parse("content://mms-sms/conversations?simple=true");
      cursor            = context.getContentResolver().query(threadListUri, null, null, null, "date ASC");

      while (cursor != null && cursor.moveToNext()) {
        long   theirThreadId     = cursor.getLong(cursor.getColumnIndexOrThrow("_id"));
        String theirRecipients   = cursor.getString(cursor.getColumnIndexOrThrow("recipient_ids"));
        Recipients ourRecipients = getOurRecipients(context, theirRecipients);

        if (ourRecipients != null) {
          long ourThreadId = threadDatabase.getThreadIdFor(ourRecipients);
          migrateConversation(context, masterSecret,
                              listener, primaryProgress,
                              theirThreadId, ourThreadId);
        }

        double position = cursor.getPosition() + 1;
        double count    = cursor.getCount();
        double progress = position / count;

        primaryProgress = (int)(progress * 10000);

        listener.progressUpdate(primaryProgress, 0);
      }
    } finally {
      if (cursor != null)
        cursor.close();
    }

    context.getSharedPreferences("SecureSMS", Context.MODE_PRIVATE).edit()
      .putBoolean("migrated", true).commit();
  }

  public interface SmsMigrationProgressListener {
    public void progressUpdate(int primaryProgress, int secondaryProgress);
  }
}