cwtch-ui/lib/models/message.dart

import 'dart:convert';
import 'package:cwtch/config.dart';
import 'package:cwtch/cwtch/cwtch.dart';
import 'package:flutter/material.dart';
import 'package:flutter/widgets.dart';
import 'package:provider/provider.dart';

import '../main.dart';
import 'messagecache.dart';
import 'messages/filemessage.dart';
import 'messages/invitemessage.dart';
import 'messages/malformedmessage.dart';
import 'messages/quotedmessage.dart';
import 'messages/textmessage.dart';
import 'profile.dart';

// Define the overlays
const TextMessageOverlay = 1;
const QuotedMessageOverlay = 10;
const SuggestContactOverlay = 100;
const InviteGroupOverlay = 101;
const FileShareOverlay = 200;

// Defines the length of the tor v3 onion address. Code using this constant will
// need to updated when we allow multiple different identifiers. At which time
// it will likely be prudent to define a proper Contact wrapper.
const TorV3ContactHandleLength = 56;

// Defines the length of a Cwtch v2 Group.
const GroupConversationHandleLength = 32;

abstract class Message {
  MessageMetadata getMetadata();

  Widget getWidget(BuildContext context, Key key);

  Widget getPreviewWidget(BuildContext context);
}

Message compileOverlay(MessageMetadata metadata, String messageData) {
  try {
    dynamic message = jsonDecode(messageData);
    var content = message['d'] as dynamic;
    var overlay = int.parse(message['o'].toString());

    switch (overlay) {
      case TextMessageOverlay:
        return TextMessage(metadata, content);
      case SuggestContactOverlay:
      case InviteGroupOverlay:
        return InviteMessage(overlay, metadata, content);
      case QuotedMessageOverlay:
        return QuotedMessage(metadata, content);
      case FileShareOverlay:
        return FileMessage(metadata, content);
      default:
        // Metadata is valid, content is not..
        return MalformedMessage(metadata);
    }
  } catch (e) {
    return MalformedMessage(metadata);
  }
}

abstract class CacheHandler {
  //Future<MessageInfo?> lookup(MessageCache cache);
  //Future<MessageInfo?> fetch(Cwtch cwtch, String profileOnion, int conversationIdentifier, MessageCache cache);

  Future<MessageInfo?> get(Cwtch cwtch, String profileOnion, int conversationIdentifier, MessageCache cache);
  //void add(MessageCache cache, MessageInfo messageInfo);
}

class ByIndex implements CacheHandler {
  int index;

  ByIndex(this.index);

  Future<MessageInfo?> lookup(MessageCache cache) async {
    var msg = cache.getByIndex(index);
    return msg;
  }

  Future<MessageInfo?> get( Cwtch cwtch, String profileOnion, int conversationIdentifier, MessageCache cache) async {
    var chunk = 40;
    if (chunk > cache.storageMessageCount - index) {
      chunk = cache.storageMessageCount - index;
    }

    if (index < cache.cacheByIndex.length) {
      return cache.getByIndex(index);
    }
    cache.lockIndexs(index, index+chunk);
    var msgs = await cwtch.GetMessages(profileOnion, conversationIdentifier, index, chunk);
    int i = 0; // declared here for use in finally to unlock
    try {
      List<dynamic> messagesWrapper = jsonDecode(msgs);

      for(; i < messagesWrapper.length; i++) {
        var messageInfo = messageWrapperToInfo(profileOnion, conversationIdentifier, messagesWrapper[i]);
        cache.addIndexed(messageInfo, index + i);
      }
      //messageWrapperToInfo
    } catch (e, stacktrace) {
      EnvironmentConfig.debugLog("Error: Getting indexed messages $index to ${index+chunk} failed parsing: " + e.toString() + " " + stacktrace.toString());
    } finally {
      // todo unlock remaining and mark malformed
      if (i != chunk) {
        cache.malformIndexes(index+i, index+chunk);
      }
    }
    return cache.getByIndex(index);
  }

  void add(MessageCache cache, MessageInfo messageInfo) {
    cache.addIndexed(messageInfo, index);
  }
}

class ById implements CacheHandler {
  int id;

  ById(this.id);

  Future<MessageInfo?> lookup(MessageCache cache) {
    return Future<MessageInfo?>.value(cache.getById(id));
  }

  Future<MessageInfo?> fetch(Cwtch cwtch, String profileOnion, int conversationIdentifier, MessageCache cache) async {
    var rawMessageEnvelope = await cwtch.GetMessageByID(profileOnion, conversationIdentifier, id);
    var messageInfo = messageJsonToInfo(profileOnion, conversationIdentifier, rawMessageEnvelope);
    if (messageInfo == null) {
      return Future.value(null);
    }
    cache.addUnindexed(messageInfo);
    return Future.value(messageInfo);
  }

  Future<MessageInfo?> get(Cwtch cwtch, String profileOnion, int conversationIdentifier, MessageCache cache) async {
    var messageInfo = await lookup(cache);
    if (messageInfo != null) {
      return Future.value(messageInfo);
    }
    return fetch(cwtch, profileOnion, conversationIdentifier, cache);
  }

}

class ByContentHash implements CacheHandler {
  String hash;

  ByContentHash(this.hash);

  Future<MessageInfo?> lookup(MessageCache cache) {
    return Future<MessageInfo?>.value(cache.getByContentHash(hash));
  }

  Future<MessageInfo?> fetch(Cwtch cwtch, String profileOnion, int conversationIdentifier, MessageCache cache) async {
    var rawMessageEnvelope = await cwtch.GetMessageByContentHash(profileOnion, conversationIdentifier, hash);
    var messageInfo = messageJsonToInfo(profileOnion, conversationIdentifier, rawMessageEnvelope);
    if (messageInfo == null) {
      return Future.value(null);
    }
    cache.addUnindexed(messageInfo);
    return Future.value(messageInfo);
  }

  Future<MessageInfo?> get( Cwtch cwtch, String profileOnion, int conversationIdentifier, MessageCache cache) async {
    var messageInfo = await lookup(cache);
    if (messageInfo != null) {
      return Future.value(messageInfo);
    }
    return fetch(cwtch, profileOnion, conversationIdentifier, cache);
  }
}

Future<Message> messageHandler(BuildContext context, String profileOnion, int conversationIdentifier, CacheHandler cacheHandler) async {
  var malformedMetadata = MessageMetadata(profileOnion, conversationIdentifier, 0, DateTime.now(), "", "", "", <String, String>{}, false, true, false, "");
  var cwtch = Provider.of<FlwtchState>(context, listen: false).cwtch;

  MessageCache? cache;
  try {
    cache = Provider
        .of<ProfileInfoState>(context, listen: false)
        .contactList
        .getContact(conversationIdentifier)
        ?.messageCache;
    if (cache == null) {
      EnvironmentConfig.debugLog("error: cannot get message cache for profile: $profileOnion conversation: $conversationIdentifier");
      return MalformedMessage(malformedMetadata);
    }
  } catch (e) {
    EnvironmentConfig.debugLog("message handler exception on get from cache: $e");
    // provider check failed...make an expensive call...
    return MalformedMessage(malformedMetadata);
  }

  MessageInfo? messageInfo = await cacheHandler.get(cwtch, profileOnion, conversationIdentifier, cache);

  if (messageInfo != null) {
    return compileOverlay(messageInfo.metadata, messageInfo.wrapper);
  } else {
    return MalformedMessage(malformedMetadata);
  }
}

MessageInfo? messageJsonToInfo(String profileOnion, int conversationIdentifier, dynamic messageJson) {
  try {
    dynamic messageWrapper = jsonDecode(messageJson);

    if (messageWrapper == null || messageWrapper['Message'] == '' || messageWrapper['Message'] == '{}') {
      return null;
    }

    return messageWrapperToInfo(profileOnion, conversationIdentifier, messageWrapper);
  } catch (e, stacktrace) {
    EnvironmentConfig.debugLog("message handler exception on parse message and cache: " + e.toString() + " " + stacktrace.toString());
    return null;
  }
}

MessageInfo messageWrapperToInfo(String profileOnion, int conversationIdentifier, dynamic messageWrapper) {
  // Construct the initial metadata
  var messageID = messageWrapper['ID'];
  var timestamp = DateTime.tryParse(messageWrapper['Timestamp'])!;
  var senderHandle = messageWrapper['PeerID'];
  var senderImage = messageWrapper['ContactImage'];
  var attributes = messageWrapper['Attributes'];
  var ackd = messageWrapper['Acknowledged'];
  var error = messageWrapper['Error'] != null;
  var signature = messageWrapper['Signature'];
  var contenthash = messageWrapper['ContentHash'];
  var metadata = MessageMetadata(profileOnion, conversationIdentifier, messageID, timestamp, senderHandle, senderImage, signature, attributes, ackd, error, false, contenthash);
  var messageInfo = new MessageInfo(metadata, messageWrapper['Message']);

  return messageInfo;
}

class MessageMetadata extends ChangeNotifier {
  // meta-metadata
  final String profileOnion;
  final int conversationIdentifier;
  final int messageID;

  final DateTime timestamp;
  final String senderHandle;
  final String? senderImage;
  final dynamic _attributes;
  bool _ackd;
  bool _error;
  final bool isAuto;

  final String? signature;
  final String contenthash;

  dynamic get attributes => this._attributes;

  bool get ackd => this._ackd;

  set ackd(bool newVal) {
    this._ackd = newVal;
    notifyListeners();
  }

  bool get error => this._error;

  set error(bool newVal) {
    this._error = newVal;
    notifyListeners();
  }

  MessageMetadata(
      this.profileOnion, this.conversationIdentifier, this.messageID, this.timestamp, this.senderHandle, this.senderImage, this.signature, this._attributes, this._ackd, this._error, this.isAuto, this.contenthash);
}