Merge pull request #3 from Brice-W/refactor

Refactor

libsession/build.gradle

@@ -38,7 +38,10 @@ dependencies {
     implementation 'androidx.core:core-ktx:1.3.2'
     implementation 'androidx.appcompat:appcompat:1.2.0'
     implementation 'com.google.android.material:material:1.2.1'
+    implementation "com.google.protobuf:protobuf-java:$protobufVersion"
     testImplementation 'junit:junit:4.+'
     androidTestImplementation 'androidx.test.ext:junit:1.1.2'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
+
+    implementation project(":libsignal")
 }

libsession/src/main/java/org/session/libsession/messaging/messages/Destination.kt

@@ -1,5 +1,12 @@
-package org.session.messaging.messages
+package org.session.libsession.messaging.messages
 
-enum class Destination {
+sealed class Destination {
 
+    class Contact(val publicKey: String)
+    class ClosedGroup(val groupPublicKey: String)
+    class OpenGroup(val channel: Long, val server: String)
+
+    companion object {
+        //TODO need to implement the equivalent to TSThread and then implement from(...)
+    }
 }

libsession/src/main/java/org/session/libsession/messaging/messages/Message.kt

@@ -1,5 +1,30 @@
-package org.session.messaging.messages
+package org.session.libsession.messaging.messages
 
-open class Message {
+import org.session.libsignal.service.internal.push.SignalServiceProtos
+
+abstract class Message {
+
+    var id: String? = null
+    var threadID: String? = null
+    var sentTimestamp: Long? = null
+    var receivedTimestamp: Long? = null
+    var recipient: String? = null
+    var sender: String? = null
+    var groupPublicKey: String? = null
+    var openGroupServerMessageID: Long? = null
+
+    companion object {
+        @JvmStatic
+        val ttl = 2 * 24 * 60 * 60 * 1000 //TODO not sure about that declaration
+    }
+
+    // validation
+    open fun isValid(): Boolean {
+        sentTimestamp = if (sentTimestamp!! > 0) sentTimestamp else return false
+        receivedTimestamp = if (receivedTimestamp!! > 0) receivedTimestamp else return false
+        return sender != null && recipient != null
+    }
+
+    abstract fun toProto(): SignalServiceProtos.Content?
 
 }

libsession/src/main/java/org/session/libsession/messaging/messages/control/ClosedGroupUpdate.kt

@@ -1,4 +1,154 @@
-package org.session.messaging.messages.control
+package org.session.libsession.messaging.messages.control
 
-class ClosedGroupUpdate : ControlMessage() {
+import com.google.protobuf.ByteString
+import org.session.libsignal.libsignal.logging.Log
+import org.session.libsignal.service.internal.push.SignalServiceProtos
+import org.session.libsignal.service.loki.protocol.closedgroups.ClosedGroupSenderKey
+
+class ClosedGroupUpdate() : ControlMessage() {
+
+    var kind: Kind? = null
+
+    // Kind enum
+    sealed class Kind {
+        class New(val groupPublicKey: ByteArray, val name: String, val groupPrivateKey: ByteArray, val senderKeys: Collection<org.session.libsignal.service.loki.protocol.closedgroups.ClosedGroupSenderKey>, val members: Collection<ByteArray>, val admins: Collection<ByteArray>) : Kind()
+        class Info(val groupPublicKey: ByteArray, val name: String, val senderKeys: Collection<org.session.libsignal.service.loki.protocol.closedgroups.ClosedGroupSenderKey>, val members: Collection<ByteArray>, val admins: Collection<ByteArray>) : Kind()
+        class SenderKeyRequest(val groupPublicKey: ByteArray) : Kind()
+        class SenderKey(val groupPublicKey: ByteArray, val senderKey: org.session.libsignal.service.loki.protocol.closedgroups.ClosedGroupSenderKey) : Kind()
+    }
+
+    companion object {
+        const val TAG = "ClosedGroupUpdate"
+
+        fun fromProto(proto: SignalServiceProtos.Content): ClosedGroupUpdate? {
+            val closedGroupUpdateProto = proto.dataMessage?.closedGroupUpdate ?: return null
+            val groupPublicKey = closedGroupUpdateProto.groupPublicKey
+            var kind: Kind
+            when(closedGroupUpdateProto.type) {
+                SignalServiceProtos.ClosedGroupUpdate.Type.NEW -> {
+                    val name = closedGroupUpdateProto.name ?: return null
+                    val groupPrivateKey = closedGroupUpdateProto.groupPrivateKey ?: return null
+                    val senderKeys = closedGroupUpdateProto.senderKeysList.map { ClosedGroupSenderKey.fromProto(it) }
+                    kind = Kind.New(
+                            groupPublicKey = groupPublicKey.toByteArray(),
+                            name = name,
+                            groupPrivateKey = groupPrivateKey.toByteArray(),
+                            senderKeys = senderKeys,
+                            members = closedGroupUpdateProto.membersList.map { it.toByteArray() },
+                            admins = closedGroupUpdateProto.adminsList.map { it.toByteArray() }
+                    )
+                }
+                SignalServiceProtos.ClosedGroupUpdate.Type.INFO -> {
+                    val name = closedGroupUpdateProto.name ?: return null
+                    val senderKeys = closedGroupUpdateProto.senderKeysList.map { ClosedGroupSenderKey.fromProto(it) }
+                    kind = Kind.Info(
+                            groupPublicKey = groupPublicKey.toByteArray(),
+                            name = name,
+                            senderKeys = senderKeys,
+                            members = closedGroupUpdateProto.membersList.map { it.toByteArray() },
+                            admins = closedGroupUpdateProto.adminsList.map { it.toByteArray() }
+                    )
+                }
+                SignalServiceProtos.ClosedGroupUpdate.Type.SENDER_KEY_REQUEST -> {
+                    kind = Kind.SenderKeyRequest(groupPublicKey = groupPublicKey.toByteArray())
+                }
+                SignalServiceProtos.ClosedGroupUpdate.Type.SENDER_KEY -> {
+                    val senderKeyProto = closedGroupUpdateProto.senderKeysList?.first() ?: return null
+                    kind = Kind.SenderKey(
+                            groupPublicKey = groupPublicKey.toByteArray(),
+                            senderKey = ClosedGroupSenderKey.fromProto(senderKeyProto)
+                    )
+                }
+            }
+            return ClosedGroupUpdate(kind)
+        }
+    }
+
+    // constructor
+    internal constructor(kind: Kind?) : this() {
+        this.kind = kind
+    }
+
+    // validation
+    override fun isValid(): Boolean {
+        if (!super.isValid()) return false
+        val kind = kind ?: return false
+        when(kind) {
+            is Kind.New -> {
+                return !kind.groupPublicKey.isEmpty() && !kind.name.isEmpty() && !kind.groupPrivateKey.isEmpty() && !kind.members.isEmpty() && !kind.admins.isEmpty()
+            }
+            is Kind.Info -> {
+                return !kind.groupPublicKey.isEmpty() && !kind.name.isEmpty() && !kind.members.isEmpty() && !kind.admins.isEmpty()
+            }
+            is Kind.SenderKeyRequest -> {
+                return !kind.groupPublicKey.isEmpty()
+            }
+            is Kind.SenderKey -> {
+                return !kind.groupPublicKey.isEmpty()
+            }
+        }
+    }
+
+    override fun toProto(): SignalServiceProtos.Content? {
+        val kind = kind
+        if (kind == null) {
+            Log.w(TAG, "Couldn't construct closed group update proto from: $this")
+            return null
+        }
+        try {
+            val closedGroupUpdate: SignalServiceProtos.ClosedGroupUpdate.Builder = SignalServiceProtos.ClosedGroupUpdate.newBuilder()
+            when (kind) {
+                is Kind.New -> {
+                    closedGroupUpdate.groupPublicKey = ByteString.copyFrom(kind.groupPublicKey)
+                    closedGroupUpdate.type = SignalServiceProtos.ClosedGroupUpdate.Type.NEW
+                    closedGroupUpdate.name = kind.name
+                    closedGroupUpdate.groupPrivateKey = ByteString.copyFrom(kind.groupPrivateKey)
+                    closedGroupUpdate.addAllSenderKeys(kind.senderKeys.map { it.toProto() })
+                    closedGroupUpdate.addAllMembers(kind.members.map { ByteString.copyFrom(it) })
+                    closedGroupUpdate.addAllAdmins(kind.admins.map { ByteString.copyFrom(it) })
+                }
+                is Kind.Info -> {
+                    closedGroupUpdate.groupPublicKey = ByteString.copyFrom(kind.groupPublicKey)
+                    closedGroupUpdate.type = SignalServiceProtos.ClosedGroupUpdate.Type.INFO
+                    closedGroupUpdate.name = kind.name
+                    closedGroupUpdate.addAllSenderKeys(kind.senderKeys.map { it.toProto() })
+                    closedGroupUpdate.addAllMembers(kind.members.map { ByteString.copyFrom(it) })
+                    closedGroupUpdate.addAllAdmins(kind.admins.map { ByteString.copyFrom(it) })
+                }
+                is Kind.SenderKeyRequest -> {
+                    closedGroupUpdate.groupPublicKey = ByteString.copyFrom(kind.groupPublicKey)
+                    closedGroupUpdate.type = SignalServiceProtos.ClosedGroupUpdate.Type.SENDER_KEY_REQUEST
+                }
+                is Kind.SenderKey -> {
+                    closedGroupUpdate.groupPublicKey = ByteString.copyFrom(kind.groupPublicKey)
+                    closedGroupUpdate.type = SignalServiceProtos.ClosedGroupUpdate.Type.SENDER_KEY
+                    closedGroupUpdate.addAllSenderKeys(listOf( kind.senderKey.toProto() ))
+                }
+            }
+            val contentProto = SignalServiceProtos.Content.newBuilder()
+            val dataMessageProto = SignalServiceProtos.DataMessage.newBuilder()
+            dataMessageProto.closedGroupUpdate = closedGroupUpdate.build()
+            contentProto.dataMessage = dataMessageProto.build()
+            return contentProto.build()
+        } catch (e: Exception) {
+            Log.w(TAG, "Couldn't construct closed group update proto from: $this")
+            return null
+        }
+        return null
+    }
+
+}
+
+// extension functions to class ClosedGroupSenderKey
+
+private fun ClosedGroupSenderKey.Companion.fromProto(proto: SignalServiceProtos.ClosedGroupUpdate.SenderKey): ClosedGroupSenderKey {
+    return ClosedGroupSenderKey(chainKey = proto.chainKey.toByteArray(), keyIndex = proto.keyIndex, publicKey = proto.publicKey.toByteArray())
+}
+
+private fun ClosedGroupSenderKey.toProto(): SignalServiceProtos.ClosedGroupUpdate.SenderKey {
+    val proto = SignalServiceProtos.ClosedGroupUpdate.SenderKey.newBuilder()
+    proto.chainKey = ByteString.copyFrom(chainKey)
+    proto.keyIndex = keyIndex
+    proto.publicKey = ByteString.copyFrom(publicKey)
+    return proto.build()
 }

libsession/src/main/java/org/session/libsession/messaging/messages/control/ControlMessage.kt

@@ -1,6 +1,6 @@
-package org.session.messaging.messages.control
+package org.session.libsession.messaging.messages.control
 
-import org.session.messaging.messages.Message
+import org.session.libsession.messaging.messages.Message
 
-open class ControlMessage : Message() {
+abstract class ControlMessage : Message() {
 }

libsession/src/main/java/org/session/libsession/messaging/messages/control/ExpirationTimerUpdate.kt

@@ -1,4 +1,51 @@
-package org.session.messaging.messages.control
+package org.session.libsession.messaging.messages.control
 
-class ExpirationTimerUpdate : ControlMessage() {
+import org.session.libsignal.libsignal.logging.Log
+import org.session.libsignal.service.internal.push.SignalServiceProtos
+
+class ExpirationTimerUpdate() : ControlMessage() {
+
+    var duration: Int? = 0
+
+    companion object {
+        const val TAG = "ExpirationTimerUpdate"
+
+        fun fromProto(proto: SignalServiceProtos.Content): ExpirationTimerUpdate? {
+            val dataMessageProto = proto.dataMessage ?: return null
+            val isExpirationTimerUpdate = (dataMessageProto.flags and SignalServiceProtos.DataMessage.Flags.EXPIRATION_TIMER_UPDATE_VALUE) != 0 //TODO validate that 'and' operator equivalent to Swift '&'
+            if (!isExpirationTimerUpdate) return null
+            val duration = dataMessageProto.expireTimer
+            return ExpirationTimerUpdate(duration)
+        }
+    }
+
+    //constructor
+    internal constructor(duration: Int) : this() {
+        this.duration = duration
+    }
+
+    // validation
+    override fun isValid(): Boolean {
+        if (!super.isValid()) return false
+        return duration != null
+    }
+
+    override fun toProto(): SignalServiceProtos.Content? {
+        val duration = duration
+        if (duration == null) {
+            Log.w(TAG, "Couldn't construct expiration timer update proto from: $this")
+            return null
+        }
+        val dataMessageProto = SignalServiceProtos.DataMessage.newBuilder()
+        dataMessageProto.flags = SignalServiceProtos.DataMessage.Flags.EXPIRATION_TIMER_UPDATE_VALUE
+        dataMessageProto.expireTimer = duration
+        val contentProto = SignalServiceProtos.Content.newBuilder()
+        try {
+            contentProto.dataMessage = dataMessageProto.build()
+            return contentProto.build()
+        } catch (e: Exception) {
+            Log.w(TAG, "Couldn't construct expiration timer update proto from: $this")
+            return null
+        }
+    }
 }

libsession/src/main/java/org/session/libsession/messaging/messages/control/ReadReceipt.kt

@@ -1,4 +1,53 @@
-package org.session.messaging.messages.control
+package org.session.libsession.messaging.messages.control
 
-class ReadReceipt : ControlMessage() {
+import org.session.libsignal.libsignal.logging.Log
+import org.session.libsignal.service.internal.push.SignalServiceProtos
+
+class ReadReceipt() : ControlMessage() {
+
+    var timestamps: LongArray? = null
+
+    companion object {
+        const val TAG = "ReadReceipt"
+
+        fun fromProto(proto: SignalServiceProtos.Content): ReadReceipt? {
+            val receiptProto = proto.receiptMessage ?: return null
+            if (receiptProto.type != SignalServiceProtos.ReceiptMessage.Type.READ) return null
+            val timestamps = receiptProto.timestampList
+            if (timestamps.isEmpty()) return null
+            return ReadReceipt(timestamps = timestamps.toLongArray())
+        }
+    }
+
+    //constructor
+    internal constructor(timestamps: LongArray?) : this() {
+        this.timestamps = timestamps
+    }
+
+    // validation
+    override fun isValid(): Boolean {
+        if (!super.isValid()) return false
+        val timestamps = timestamps ?: return false
+        if (timestamps.isNotEmpty()) { return true }
+        return false
+    }
+
+    override fun toProto(): SignalServiceProtos.Content? {
+        val timestamps = timestamps
+        if (timestamps == null) {
+            Log.w(ExpirationTimerUpdate.TAG, "Couldn't construct read receipt proto from: $this")
+            return null
+        }
+        val receiptProto = SignalServiceProtos.ReceiptMessage.newBuilder()
+        receiptProto.type = SignalServiceProtos.ReceiptMessage.Type.READ
+        receiptProto.addAllTimestamp(timestamps.asIterable())
+        val contentProto = SignalServiceProtos.Content.newBuilder()
+        try {
+            contentProto.receiptMessage = receiptProto.build()
+            return contentProto.build()
+        } catch (e: Exception) {
+            Log.w(ExpirationTimerUpdate.TAG, "Couldn't construct read receipt proto from: $this")
+            return null
+        }
+    }
 }

libsession/src/main/java/org/session/libsession/messaging/messages/control/TypingIndicator.kt

@@ -1,4 +1,75 @@
-package org.session.messaging.messages.control
+package org.session.libsession.messaging.messages.control
 
-class TypingIndicator : ControlMessage() {
+import org.session.libsignal.libsignal.logging.Log
+import org.session.libsignal.service.internal.push.SignalServiceProtos
+
+class TypingIndicator() : ControlMessage() {
+
+    companion object {
+        const val TAG = "TypingIndicator"
+
+        //val ttl:  30 * 1000 //TODO
+
+        fun fromProto(proto: SignalServiceProtos.Content): TypingIndicator? {
+            val typingIndicatorProto = proto.typingMessage ?: return null
+            val kind = Kind.fromProto(typingIndicatorProto.action)
+            return TypingIndicator(kind = kind)
+        }
+    }
+
+    // Kind enum
+    enum class Kind {
+        STARTED,
+        STOPPED,
+        ;
+
+        companion object {
+            @JvmStatic
+            fun fromProto(proto: SignalServiceProtos.TypingMessage.Action): Kind =
+                when (proto) {
+                    SignalServiceProtos.TypingMessage.Action.STARTED -> STARTED
+                    SignalServiceProtos.TypingMessage.Action.STOPPED -> STOPPED
+                }
+        }
+
+        fun toProto(): SignalServiceProtos.TypingMessage.Action {
+            when (this) {
+                STARTED -> return SignalServiceProtos.TypingMessage.Action.STARTED
+                STOPPED -> return SignalServiceProtos.TypingMessage.Action.STOPPED
+            }
+        }
+    }
+
+    var kind: Kind? = null
+
+    //constructor
+    internal constructor(kind: Kind) : this() {
+        this.kind = kind
+    }
+
+    // validation
+    override fun isValid(): Boolean {
+        if (!super.isValid()) return false
+        return kind != null
+    }
+
+    override fun toProto(): SignalServiceProtos.Content? {
+        val timestamp = sentTimestamp
+        val kind = kind
+        if (timestamp == null || kind == null) {
+            Log.w(TAG, "Couldn't construct typing indicator proto from: $this")
+            return null
+        }
+        val typingIndicatorProto = SignalServiceProtos.TypingMessage.newBuilder()
+        typingIndicatorProto.timestamp = timestamp
+        typingIndicatorProto.action = kind.toProto()
+        val contentProto = SignalServiceProtos.Content.newBuilder()
+        try {
+            contentProto.typingMessage = typingIndicatorProto.build()
+            return contentProto.build()
+        } catch (e: Exception) {
+            Log.w(TAG, "Couldn't construct typing indicator proto from: $this")
+            return null
+        }
+    }
 }

libsession/src/main/java/org/session/libsession/messaging/messages/control/unused/NullMessage.kt

@@ -1,6 +1,37 @@
-package org.session.messaging.messages.control.unused
+package org.session.libsession.messaging.messages.control.unused
 
-import org.session.messaging.messages.control.ControlMessage
+import com.google.protobuf.ByteString
+import org.session.libsession.messaging.messages.control.ControlMessage
+import org.session.libsession.messaging.messages.control.TypingIndicator
+import org.session.libsignal.libsignal.logging.Log
+import org.session.libsignal.service.internal.push.SignalServiceProtos
+import java.security.SecureRandom
 
-class NullMessage : ControlMessage() {
+class NullMessage() : ControlMessage() {
+
+
+    companion object {
+        const val TAG = "NullMessage"
+
+        fun fromProto(proto: SignalServiceProtos.Content): NullMessage? {
+            if (proto.nullMessage == null) return null
+            return NullMessage()
+        }
+    }
+
+    override fun toProto(): SignalServiceProtos.Content? {
+        val nullMessageProto = SignalServiceProtos.NullMessage.newBuilder()
+        val sr = SecureRandom()
+        val paddingSize = sr.nextInt(512)
+        val padding = ByteArray(paddingSize)
+        nullMessageProto.padding = ByteString.copyFrom(padding)
+        val contentProto = SignalServiceProtos.Content.newBuilder()
+        try {
+            contentProto.nullMessage = nullMessageProto.build()
+            return contentProto.build()
+        } catch (e: Exception) {
+            Log.w(TAG, "Couldn't construct null message proto from: $this")
+            return null
+        }
+    }
 }

libsession/src/main/java/org/session/libsession/messaging/messages/control/unused/SessionRequest.kt

@@ -1,6 +1,81 @@
-package org.session.messaging.messages.control.unused
+package org.session.libsession.messaging.messages.control.unused
 
-import org.session.messaging.messages.control.ControlMessage
+import com.google.protobuf.ByteString
+import org.session.libsession.messaging.messages.control.ControlMessage
+import org.session.libsession.messaging.messages.control.ExpirationTimerUpdate
+import org.session.libsession.messaging.messages.control.TypingIndicator
+import org.session.libsignal.libsignal.logging.Log
+import org.session.libsignal.libsignal.state.PreKeyBundle
+import org.session.libsignal.service.internal.push.SignalServiceProtos
+import java.security.SecureRandom
 
-class SessionRequest : ControlMessage() {
+class SessionRequest() : ControlMessage() {
+
+    var preKeyBundle: PreKeyBundle? = null
+
+    companion object {
+        const val TAG = "SessionRequest"
+
+        fun fromProto(proto: SignalServiceProtos.Content): SessionRequest? {
+            if (proto.nullMessage == null) return null
+            val preKeyBundleProto = proto.preKeyBundleMessage ?: return null
+            val registrationID: Int = 0
+            //TODO looks like database stuff here
+            /*iOS code: Configuration.shared.storage.with { transaction in
+                    registrationID = Configuration.shared.storage.getOrGenerateRegistrationID(using: transaction)
+            }*/
+            val preKeyBundle = PreKeyBundle(
+                    registrationID,
+                    1,
+                    preKeyBundleProto.preKeyId,
+                    null, //TODO preKeyBundleProto.preKey,
+                    0, //TODO preKeyBundleProto.signedKey,
+                    null, //TODO preKeyBundleProto.signedKeyId,
+                    preKeyBundleProto.signature.toByteArray(),
+                    null, //TODO preKeyBundleProto.identityKey
+            )
+            return SessionRequest(preKeyBundle)
+        }
+    }
+
+    //constructor
+    internal constructor(preKeyBundle: PreKeyBundle) : this() {
+        this.preKeyBundle = preKeyBundle
+    }
+
+    // validation
+    override fun isValid(): Boolean {
+        if (!super.isValid()) return false
+        return preKeyBundle != null
+    }
+
+    override fun toProto(): SignalServiceProtos.Content? {
+        val preKeyBundle = preKeyBundle
+        if (preKeyBundle == null) {
+            Log.w(TAG, "Couldn't construct session request proto from: $this")
+            return null
+        }
+        val nullMessageProto = SignalServiceProtos.NullMessage.newBuilder()
+        val sr = SecureRandom()
+        val paddingSize = sr.nextInt(512)
+        val padding = ByteArray(paddingSize)
+        nullMessageProto.padding = ByteString.copyFrom(padding)
+        val preKeyBundleProto = SignalServiceProtos.PreKeyBundleMessage.newBuilder()
+        //TODO preKeyBundleProto.identityKey = preKeyBundle.identityKey
+        preKeyBundleProto.deviceId = preKeyBundle.deviceId
+        preKeyBundleProto.preKeyId = preKeyBundle.preKeyId
+        //TODO preKeyBundleProto.preKey = preKeyBundle.preKeyPublic
+        preKeyBundleProto.signedKeyId = preKeyBundle.signedPreKeyId
+        //TODO preKeyBundleProto.signedKey = preKeyBundle.signedPreKeyPublic
+        preKeyBundleProto.signature = ByteString.copyFrom(preKeyBundle.signedPreKeySignature)
+        val contentProto = SignalServiceProtos.Content.newBuilder()
+        try {
+            contentProto.nullMessage = nullMessageProto.build()
+            contentProto.preKeyBundleMessage = preKeyBundleProto.build()
+            return contentProto.build()
+        } catch (e: Exception) {
+            Log.w(TAG, "Couldn't construct session request proto from: $this")
+            return null
+        }
+    }
 }

libsession/src/main/java/org/session/libsession/messaging/messages/visible/Attachment.kt

@@ -0,0 +1,71 @@
+package org.session.libsession.messaging.messages.visible
+
+import android.util.Size
+import android.webkit.MimeTypeMap
+import org.session.libsignal.service.internal.push.SignalServiceProtos
+import java.io.File
+import java.net.URL
+import kotlin.math.absoluteValue
+
+class Attachment : VisibleMessage<SignalServiceProtos.AttachmentPointer?>() {
+
+    var fileName: String? = null
+    var contentType: String? = null
+    var key: ByteArray? = null
+    var digest: ByteArray? = null
+    var kind: Kind? = null
+    var caption: String? = null
+    var size: Size? = null
+    var sizeInBytes: Int? = 0
+    var url: String? = null
+
+    companion object {
+        fun fromProto(proto: SignalServiceProtos.AttachmentPointer): Attachment? {
+            val result = Attachment()
+            result.fileName = proto.fileName
+            fun inferContentType(): String {
+                val fileName = result.fileName ?: return "application/octet-stream" //TODO find equivalent to OWSMimeTypeApplicationOctetStream
+                val fileExtension = File(fileName).extension
+                val mimeTypeMap = MimeTypeMap.getSingleton()
+                return mimeTypeMap.getMimeTypeFromExtension(fileExtension) ?: "application/octet-stream" //TODO check that it's correct
+            }
+            result.contentType = proto.contentType ?: inferContentType()
+            result.key = proto.key.toByteArray()
+            result.digest = proto.digest.toByteArray()
+            val kind: Kind
+            if (proto.hasFlags() && (proto.flags and SignalServiceProtos.AttachmentPointer.Flags.VOICE_MESSAGE_VALUE) > 0) { //TODO validate that 'and' operator = swift '&'
+                kind = Kind.VOICEMESSAGE
+            } else {
+                kind = Kind.GENERIC
+            }
+            result.kind = kind
+            result.caption = if (proto.hasCaption()) proto.caption else null
+            val size: Size
+            if (proto.hasWidth() && proto.width > 0 && proto.hasHeight() && proto.height > 0) {
+                size = Size(proto.width, proto.height)
+            } else {
+                size = Size(0,0) //TODO check that it's equivalent to swift: CGSize.zero
+            }
+            result.size = size
+            result.sizeInBytes = if (proto.size > 0) proto.size else null
+            result. url = proto.url
+            return result
+        }
+    }
+
+    enum class Kind {
+        VOICEMESSAGE,
+        GENERIC
+    }
+
+    // validation
+    override fun isValid(): Boolean {
+        if (!super.isValid()) return false
+        // key and digest can be nil for open group attachments
+        return (contentType != null && kind != null && size != null && sizeInBytes != null && url != null)
+    }
+
+    override fun toProto(transaction: String): SignalServiceProtos.AttachmentPointer? {
+        TODO("Not implemented")
+    }
+}

libsession/src/main/java/org/session/libsession/messaging/messages/visible/BaseVisibleMessage.kt

@@ -0,0 +1,102 @@
+package org.session.libsession.messaging.messages.visible
+
+import org.session.libsignal.libsignal.logging.Log
+import org.session.libsignal.service.internal.push.SignalServiceProtos
+
+class BaseVisibleMessage() : VisibleMessage<SignalServiceProtos.Content?>() {
+
+    var text: String? = null
+    var attachmentIDs = ArrayList<String>()
+    var quote: Quote? = null
+    var linkPreview: LinkPreview? = null
+    var contact: Contact? = null
+    var profile: Profile? = null
+
+    companion object {
+        const val TAG = "BaseVisibleMessage"
+
+        fun fromProto(proto: SignalServiceProtos.Content): BaseVisibleMessage? {
+            val dataMessage = proto.dataMessage ?: return null
+            val result = BaseVisibleMessage()
+            result.text = dataMessage.body
+            // Attachments are handled in MessageReceiver
+            val quoteProto = dataMessage.quote
+            quoteProto?.let {
+                val quote = Quote.fromProto(quoteProto)
+                quote?.let { result.quote = quote }
+            }
+            val linkPreviewProto = dataMessage.previewList.first()
+            linkPreviewProto?.let {
+                val linkPreview = LinkPreview.fromProto(linkPreviewProto)
+                linkPreview?.let { result.linkPreview = linkPreview }
+            }
+            // TODO Contact
+            val profile = Profile.fromProto(dataMessage)
+            profile?.let { result.profile = profile }
+            return  result
+        }
+    }
+
+    // validation
+    override fun isValid(): Boolean {
+        if (!super.isValid()) return false
+        if (attachmentIDs.isNotEmpty()) return true
+        val text = text?.trim() ?: return false
+        if (text.isNotEmpty()) return true
+        return false
+    }
+
+    override fun toProto(transaction: String): SignalServiceProtos.Content? {
+        val proto = SignalServiceProtos.Content.newBuilder()
+        var attachmentIDs = this.attachmentIDs
+        val dataMessage: SignalServiceProtos.DataMessage.Builder
+        // Profile
+        val profile = profile
+        val profileProto = profile?.toSSProto()
+        if (profileProto != null) {
+            dataMessage = profileProto.toBuilder()
+        } else {
+            dataMessage = SignalServiceProtos.DataMessage.newBuilder()
+        }
+        // Text
+        text?.let { dataMessage.body = text }
+        // Quote
+        val quotedAttachmentID = quote?.attachmentID
+        quotedAttachmentID?.let {
+            val index = attachmentIDs.indexOf(quotedAttachmentID)
+            if (index >= 0) { attachmentIDs.removeAt(index) }
+        }
+        val quote = quote
+        quote?.let {
+            val quoteProto = quote.toProto(transaction)
+            if (quoteProto != null) dataMessage.quote = quoteProto
+        }
+        //Link preview
+        val linkPreviewAttachmentID = linkPreview?.attachmentID
+        linkPreviewAttachmentID?.let {
+            val index = attachmentIDs.indexOf(quotedAttachmentID)
+            if (index >= 0) { attachmentIDs.removeAt(index) }
+        }
+        val linkPreview = linkPreview
+        linkPreview?.let {
+            val linkPreviewProto = linkPreview.toProto(transaction)
+            linkPreviewProto?.let {
+                dataMessage.addAllPreview(listOf(linkPreviewProto))
+            }
+        }
+        //Attachments
+        // TODO I'm blocking on that one...
+        //swift: let attachments = attachmentIDs.compactMap { TSAttachmentStream.fetch(uniqueId: $0, transaction: transaction) }
+
+        // TODO Contact
+        // Build
+        try {
+            proto.dataMessage = dataMessage.build()
+            return proto.build()
+        } catch (e: Exception) {
+            Log.w(TAG, "Couldn't construct visible message proto from: $this")
+            return null
+        }
+    }
+
+}

libsession/src/main/java/org/session/libsession/messaging/messages/visible/Contact.kt

@@ -1,4 +1,16 @@
-package org.session.messaging.messages.visible
+package org.session.libsession.messaging.messages.visible
 
-internal class Contact {
+import org.session.libsignal.service.internal.push.SignalServiceProtos
+
+class Contact : VisibleMessage<SignalServiceProtos.DataMessage.Contact?>() {
+
+    companion object {
+        fun fromProto(proto: SignalServiceProtos.Content): Contact? {
+            TODO("Not yet implemented")
+        }
+    }
+
+    override fun toProto(transaction: String): SignalServiceProtos.DataMessage.Contact? {
+        TODO("Not yet implemented")
+    }
 }

libsession/src/main/java/org/session/libsession/messaging/messages/visible/LinkPreview.kt

@@ -1,4 +1,58 @@
-package org.session.messaging.messages.visible
+package org.session.libsession.messaging.messages.visible
 
-internal class LinkPreview {
+import org.session.libsession.messaging.messages.control.TypingIndicator
+import org.session.libsignal.libsignal.logging.Log
+import org.session.libsignal.service.internal.push.SignalServiceProtos
+
+class LinkPreview() : VisibleMessage<SignalServiceProtos.DataMessage.Preview?>(){
+
+    var title: String? = null
+    var url: String? = null
+    var attachmentID: String? = null
+
+    companion object {
+        const val TAG = "LinkPreview"
+
+        fun fromProto(proto: SignalServiceProtos.DataMessage.Preview): LinkPreview? {
+            val title = proto.title
+            val url = proto.url
+            return LinkPreview(title, url, null)
+        }
+    }
+
+    //constructor
+    internal constructor(title: String?, url: String, attachmentID: String?) : this() {
+        this.title = title
+        this.url = url
+        this.attachmentID = attachmentID
+    }
+
+
+    // validation
+    override fun isValid(): Boolean {
+        if (!super.isValid()) return false
+        return (title != null && url != null && attachmentID != null)
+    }
+
+    override fun toProto(transaction: String): SignalServiceProtos.DataMessage.Preview? {
+        val url = url
+        if (url == null) {
+            Log.w(TAG, "Couldn't construct link preview proto from: $this")
+            return null
+        }
+        val linkPreviewProto = SignalServiceProtos.DataMessage.Preview.newBuilder()
+        linkPreviewProto.url = url
+        title?.let { linkPreviewProto.title = title }
+        val attachmentID = attachmentID
+        attachmentID?.let {
+            //TODO database stuff
+        }
+        // Build
+        try {
+            return linkPreviewProto.build()
+        } catch (e: Exception) {
+            Log.w(TAG, "Couldn't construct link preview proto from: $this")
+            return null
+        }
+    }
 }

libsession/src/main/java/org/session/libsession/messaging/messages/visible/Profile.kt

@@ -1,4 +1,64 @@
-package org.session.messaging.messages.visible
+package org.session.libsession.messaging.messages.visible
 
-internal class Profile {
+import com.google.protobuf.ByteString
+import org.session.libsignal.libsignal.logging.Log
+import org.session.libsignal.service.internal.push.SignalServiceProtos
+
+class Profile() : VisibleMessage<SignalServiceProtos.DataMessage?>() {
+
+    var displayName: String? = null
+    var profileKey: ByteArray? = null
+    var profilePictureURL: String? = null
+
+    companion object {
+        const val TAG = "Profile"
+
+        fun fromProto(proto: SignalServiceProtos.DataMessage): Profile? {
+            val profileProto = proto.profile ?: return null
+            val displayName = profileProto.displayName ?: return null
+            val profileKey = proto.profileKey
+            val profilePictureURL = profileProto.profilePictureURL
+            profileKey?.let {
+                val profilePictureURL = profilePictureURL
+                profilePictureURL?.let {
+                    return Profile(displayName = displayName, profileKey = profileKey.toByteArray(), profilePictureURL = profilePictureURL)
+                }
+            }
+            return Profile(displayName)
+        }
+    }
+
+    //constructor
+    internal constructor(displayName: String, profileKey: ByteArray? = null, profilePictureURL: String? = null) : this() {
+        this.displayName = displayName
+        this.profileKey = profileKey
+        this.profilePictureURL = profilePictureURL
+    }
+
+    fun toSSProto(): SignalServiceProtos.DataMessage? {
+        return this.toProto("")
+    }
+
+    override fun toProto(transaction: String): SignalServiceProtos.DataMessage? {
+        val displayName = displayName
+        if (displayName == null) {
+            Log.w(TAG, "Couldn't construct link preview proto from: $this")
+            return null
+        }
+        val dataMessageProto = SignalServiceProtos.DataMessage.newBuilder()
+        val profileProto = SignalServiceProtos.LokiUserProfile.newBuilder()
+        profileProto.displayName = displayName
+        val profileKey = profileKey
+        profileKey?.let { dataMessageProto.profileKey = ByteString.copyFrom(profileKey) }
+        val profilePictureURL = profilePictureURL
+        profilePictureURL?.let { profileProto.profilePictureURL = profilePictureURL }
+        // Build
+        try {
+            dataMessageProto.profile = profileProto.build()
+            return dataMessageProto.build()
+        } catch (e: Exception) {
+            Log.w(TAG, "Couldn't construct profile proto from: $this")
+            return null
+        }
+    }
 }

libsession/src/main/java/org/session/libsession/messaging/messages/visible/Quote.kt

@@ -1,4 +1,72 @@
-package org.session.messaging.messages.visible
+package org.session.libsession.messaging.messages.visible
 
-internal class Quote {
+import org.session.libsignal.libsignal.logging.Log
+import org.session.libsignal.service.internal.push.SignalServiceProtos
+
+class Quote() : VisibleMessage<SignalServiceProtos.DataMessage.Quote?>() {
+
+    var timestamp: Long? = 0
+    var publicKey: String? = null
+    var text: String? = null
+    var attachmentID: String? = null
+
+    companion object {
+        const val TAG = "Quote"
+
+        fun fromProto(proto: SignalServiceProtos.DataMessage.Quote): Quote? {
+            val timestamp = proto.id
+            val publicKey = proto.author
+            val text = proto.text
+            return Quote(timestamp, publicKey, text, null)
+        }
+    }
+
+    //constructor
+    internal constructor(timestamp: Long, publicKey: String, text: String?, attachmentID: String?) : this() {
+        this.timestamp = timestamp
+        this.publicKey = publicKey
+        this.text = text
+        this.attachmentID = attachmentID
+    }
+
+
+    // validation
+    override fun isValid(): Boolean {
+        if (!super.isValid()) return false
+        return (timestamp != null && publicKey != null)
+    }
+
+    override fun toProto(transaction: String): SignalServiceProtos.DataMessage.Quote? {
+        val timestamp = timestamp
+        val publicKey = publicKey
+        if (timestamp == null || publicKey == null) {
+            Log.w(TAG, "Couldn't construct quote proto from: $this")
+            return null
+        }
+        val quoteProto = SignalServiceProtos.DataMessage.Quote.newBuilder()
+        quoteProto.id = timestamp
+        quoteProto.author = publicKey
+        text?.let { quoteProto.text = text }
+        addAttachmentsIfNeeded(quoteProto, transaction)
+        // Build
+        try {
+            return quoteProto.build()
+        } catch (e: Exception) {
+            Log.w(TAG, "Couldn't construct quote proto from: $this")
+            return null
+        }
+    }
+
+    private fun addAttachmentsIfNeeded(quoteProto: SignalServiceProtos.DataMessage.Quote.Builder, transaction: String) {
+        val attachmentID = attachmentID ?: return
+        //TODO databas stuff
+        val quotedAttachmentProto = SignalServiceProtos.DataMessage.Quote.QuotedAttachment.newBuilder()
+        //TODO more database related stuff
+        //quotedAttachmentProto.contentType =
+        try {
+            quoteProto.addAttachments(quotedAttachmentProto.build())
+        } catch (e: Exception) {
+            Log.w(TAG, "Couldn't construct quoted attachment proto from: $this")
+        }
+    }
 }

libsession/src/main/java/org/session/libsession/messaging/messages/visible/VisibleMessage.kt

@@ -1,6 +1,15 @@
-package org.session.messaging.messages.visible
+package org.session.libsession.messaging.messages.visible
 
-import org.session.messaging.messages.Message
+import org.session.libsession.messaging.messages.Message
+import org.session.libsignal.service.internal.push.SignalServiceProtos
 
-class VisibleMessage : Message() {
+abstract class VisibleMessage<out T: com.google.protobuf.MessageOrBuilder?> : Message() {
+
+    abstract fun toProto(transaction: String): T
+
+    final override fun toProto(): SignalServiceProtos.Content? {
+        //we don't need to implement this method in subclasses
+        //TODO it just needs an equivalent to swift: preconditionFailure("Use toProto(using:) if that exists...
+        TODO("Not implemented")
+    }
 }

libsession/src/main/java/org/session/libsession/messaging/messages/visible/attachments/Attachment.kt

@@ -1,4 +0,0 @@
-package org.session.messaging.messages.visible.attachments
-
-internal class Attachment {
-}