MessagingApp_Functions/functions/chatapp-functions/lib/main.dart

import 'dart:async';
import 'dart:convert';
import 'dart:io';
import 'package:dart_appwrite/dart_appwrite.dart';

late Databases _database;

var _usersDbId;
var _conversationDbId;
var _documentId;
var _databaseId;

var _conversationLinkDbId;
late DateTime createdAt;
late DateTime updatedAt;

//Default call by function
Future<dynamic> main(final _context) async {
  try {
    final client = Client()
        .setEndpoint(
            Platform.environment['APPWRITE_FUNCTION_API_ENDPOINT'] ?? '')
        .setProject(Platform.environment['APPWRITE_FUNCTION_PROJECT_ID'] ?? '')
        .setKey(_context.req.headers['x-appwrite-key'] ?? '');

    _database = Databases(client);
    _conversationDbId = Platform.environment['CONVERSATION_COL_ID'];
    _usersDbId = Platform.environment['USERS_COL_ID'];
    _conversationLinkDbId = Platform.environment['CONVERSATION_LINK_COL_ID'];

    String trigger = _context.req.headers['x-appwrite-trigger'];
    if (trigger == 'event') {
      //
      List<dynamic> _members = _context.req.bodyJson['members'];
      List<dynamic> _messages = _context.req.bodyJson['messages'];
      _documentId = _context.req.bodyJson['\$id'];
      _databaseId = _context.req.bodyJson['\$databaseId'];

      createdAt = DateTime.parse(_context.req.bodyJson['\$createdAt']);
      updatedAt = DateTime.parse(_context.req.bodyJson['\$updatedAt']);

      // _context.log(_messages);

      Map allMessages = {};
      for (var pp = 0; pp < _messages.length; pp++) {
        allMessages.addAll(json.decode(_messages[pp]));
      }

      if (createdAt.isAtSameMomentAs(updatedAt)) {
        //
        for (var _member in _members) {
          var _linkId = await createConversation(
            _context,
            _member,
            _members.where((_data) => _data != _member).toList(),
          );

          if (_linkId != null) {
            await updateConversationLink(_context, _linkId, _documentId);
          }
        }
      } else {
        //
        for (String _member in _members) {
          await updateConversation(_context, _member, allMessages[_member]);
        }
      }
    }
  } on AppwriteException catch (e) {
    _context.error('error message (AppWrite)- ${e.message}');
  } on Exception catch (e) {
    _context.error('error message (General)- ${e.toString()}');
  }
  return _context.res.empty();
}

dynamic createConversation(final _context, String _member, var _members) async {
  //

  List<dynamic> _chatIdMap = [];
  List<dynamic> _detailMap = [];
  List<dynamic> _lastModifiedMap = [];

  var _userDetail = await _database.getDocument(
    databaseId: _databaseId,
    collectionId: _usersDbId,
    documentId: _members[0],
  );

  var _imageUrl = _userDetail.data['image'];
  var _name = _userDetail.data['name'];

  var _conversationDetail;
  try {
    _conversationDetail = await _database.getDocument(
        databaseId: _databaseId,
        collectionId: _conversationDbId,
        documentId: _member);
  } on AppwriteException catch (e) {
    e.message;
  } on Exception catch (e) {
    e.toString();
  }

  if (_conversationDetail != null) {
    _chatIdMap = _conversationDetail.data['chatId'];
    _detailMap = _conversationDetail.data['details'];
    _lastModifiedMap = _conversationDetail.data['lastModified'];

    await _database.deleteDocument(
      databaseId: _databaseId,
      collectionId: _conversationDbId,
      documentId: _member,
    );
  }

  try {
    var _data = '{"name": "$_name","image": "$_imageUrl","unseenCount": 0}';

    _chatIdMap.add(_documentId);
    _detailMap.add(_data);
    _lastModifiedMap.add(DateTime.now().toUtc().toIso8601String());

    Map<String, dynamic> _conversationMap = {
      "chatId": _chatIdMap,
      "details": _detailMap,
      "lastModified": _lastModifiedMap
    };

    await _database.createDocument(
      databaseId: _databaseId,
      collectionId: _conversationDbId,
      documentId: _member,
      data: _conversationMap,
    );
    return '$_member${_members[0]}';
  } on AppwriteException catch (e) {
    _context.log('amessage - $e.message');
    return '';
  } on Exception catch (e) {
    _context.log('emessage - $e');
    return '';
  }
}

//
dynamic updateConversation(var _context, var _member, var _messages) async {
  //
  var _message = _messages[_messages.length - 1];
  if (_message.isNotEmpty) {
    List<dynamic> _chatIdMap = [];
    List<dynamic> _detailMap = [];
    List<dynamic> _lastModifiedMap = [];

    var _conversationDetail;
    try {
      _conversationDetail = await _database.getDocument(
        databaseId: _databaseId,
        collectionId: _conversationDbId,
        documentId: _member,
      );
    } on AppwriteException catch (e) {
      e.message;
    } on Exception catch (e) {
      e.toString();
    }

    if (_conversationDetail != null) {
      _chatIdMap = _conversationDetail.data['chatId'];
      _detailMap = _conversationDetail.data['details'];
      _lastModifiedMap = _conversationDetail.data['lastModified'];

      var _index = _chatIdMap.indexOf(_documentId);
      Map _detail = json.decode(_detailMap[_index]);
      _lastModifiedMap[_index] = DateTime.now().toUtc().toIso8601String();

      _detail['unseenCount'] += 1;
      _detail['lastMessage'] = _message['message'];
      _detail['timeStamp'] = _message['timeStamp'];
      _detail['type'] = _message['type'];

      _detailMap[_index] = json.encode(_detail);
      _conversationDetail.data['details'] = _detailMap;

      Map<String, dynamic> _conversationMap = {
        "chatId": _chatIdMap,
        "details": _detailMap,
        "lastModified": _lastModifiedMap
      };

      await _database.updateDocument(
        databaseId: _databaseId,
        collectionId: _conversationDbId,
        documentId: _member,
        data: _conversationMap,
      );
    }
  }
  return '';
}

dynamic updateConversationLink(
    var _context, var _linkId, var _documentId) async {
//
  dynamic _conversationLink;

  try {
    _conversationLink = await _database.getDocument(
        databaseId: _databaseId,
        collectionId: _conversationLinkDbId,
        documentId: _linkId);
  } on AppwriteException catch (e) {
    e.message;
  } on Exception catch (e) {
    e.toString();
  }

  if (_conversationLink == null) {
    await _database.createDocument(
      databaseId: _databaseId,
      collectionId: _conversationLinkDbId,
      documentId: _linkId.substring(0, 36),
      data: {"chatId": _documentId},
    );
  }
  return '';
}