import 'package:comunic/helpers/database/conversation_messages_database_helper.dart';
import 'package:comunic/helpers/database/conversations_database_helper.dart';
import 'package:comunic/helpers/users_helper.dart';
import 'package:comunic/helpers/websocket_helper.dart';
import 'package:comunic/lists/conversation_messages_list.dart';
import 'package:comunic/lists/conversations_list.dart';
import 'package:comunic/lists/users_list.dart';
import 'package:comunic/models/api_request.dart';
import 'package:comunic/models/api_response.dart';
import 'package:comunic/models/conversation.dart';
import 'package:comunic/models/conversation_message.dart';
import 'package:comunic/models/displayed_content.dart';
import 'package:comunic/models/new_conversation_message.dart';
import 'package:comunic/utils/account_utils.dart';
import 'package:meta/meta.dart';

/// Conversation helper
///
/// @author Pierre HUBERT

enum SendMessageResult { SUCCESS, MESSAGE_REJECTED, FAILED }

class ConversationsHelper {
  static final _registeredConversations = Map<int, int>();

  final ConversationsDatabaseHelper _conversationsDatabaseHelper =
      ConversationsDatabaseHelper();
  final ConversationMessagesDatabaseHelper _conversationMessagesDatabaseHelper =
      ConversationMessagesDatabaseHelper();

  /// Create a new conversation
  ///
  /// Return the ID of the newly created conversation or -1 in case of failure
  Future<int> createConversation(Conversation settings) async {
    final response =
        await APIRequest(uri: "conversations/create", needLogin: true, args: {
      "name": settings.hasName ? settings.name : "false",
      "follow": settings.following ? "true" : "false",
      "users": settings.members.join(",")
    }).exec();

    if (response.code != 200) return -1;

    return response.getObject()["conversationID"];
  }

  /// Update an existing conversation
  ///
  /// Returns a boolean depending of the success of the operation
  Future<bool> updateConversation(Conversation settings) async {
    final request =
        APIRequest(uri: "conversations/updateSettings", needLogin: true, args: {
      "conversationID": settings.id.toString(),
      "following": settings.following ? "true" : "false"
    });

    // Update all conversation settings, if possible
    if (settings.isOwner) {
      request.addString("name", settings.hasName ? settings.name : "false");
      request.addString("members", settings.members.join(","));
    }

    final response = await request.exec();

    if (response.code != 200) return false;

    //Delete old conversation entry from the database
    await _conversationsDatabaseHelper.delete(settings.id);

    // Success
    return true;
  }

  /// Delete a conversation specified by its [id]
  Future<bool> deleteConversation(int id) async {
    final response = await APIRequest(
      uri: "conversations/delete",
      needLogin: true,
      args: {
        "conversationID": id.toString(),
      },
    ).exec();

    return response.code == 200;
  }

  /// Download the list of conversations from the server
  Future<ConversationsList> downloadList() async {
    final response =
        await APIRequest(uri: "conversations/getList", needLogin: true).exec();

    if (response.code != 200) return null;

    try {
      ConversationsList list = ConversationsList();
      response.getArray().forEach((f) => list.add(_apiToConversation(f)));

      // Update the database
      await _conversationsDatabaseHelper.clearTable();
      await _conversationsDatabaseHelper.insertAll(list);

      return list;
    } on Exception catch (e) {
      print(e.toString());
      return null;
    }
  }

  /// Get the local list of conversations
  Future<ConversationsList> getCachedList() async {
    final list = await _conversationsDatabaseHelper.getAll();
    list.sort();
    return list;
  }

  /// Get information about a single conversation specified by its [id]
  Future<Conversation> _downloadSingle(int id) async {
    try {
      final response = await APIRequest(
          uri: "conversations/getInfoOne",
          needLogin: true,
          args: {"conversationID": id.toString()}).exec();

      if (response.code != 200) return null;

      final conversation = _apiToConversation(response.getObject());
      _conversationsDatabaseHelper.insertOrUpdate(conversation);
      return conversation;
    } on Exception catch (e) {
      print(e.toString());
      print("Could not get information about a single conversation !");
      return null;
    }
  }

  /// Get information about a single conversation. If [force] is set to false,
  /// cached version of the conversation will be used, else it will always get
  /// the information from the server
  Future<Conversation> getSingle(int id, {bool force = false}) async {
    if (force || !await _conversationsDatabaseHelper.has(id))
      return await _downloadSingle(id);
    else
      return _conversationsDatabaseHelper.get(id);
  }

  /// Get the name of a [conversation]. This requires information
  /// about the users of this conversation
  static String getConversationName(
      Conversation conversation, UsersList users) {
    if (conversation.hasName) return conversation.name;

    String name = "";
    int count = 0;
    for (int i = 0; i < 3 && i < conversation.members.length; i++)
      if (conversation.members[i] != userID()) {
        name += (count > 0 ? ", " : "") +
            users.getUser(conversation.members[i]).fullName;
        count++;
      }

    if (conversation.members.length > 3) name += ", ...";

    return name;
  }

  /// Search and return a private conversation with a given [userID]. If such
  /// conversation does not exists, it is created if [allowCreate] is set to
  /// true
  Future<int> getPrivate(int userID, {bool allowCreate = true}) async {
    final response = await APIRequest(
      uri: "conversations/getPrivate",
      needLogin: true,
      args: {
        "otherUser": userID.toString(),
        "allowCreate": allowCreate.toString()
      },
    ).exec();

    if (response.code != 200) return null;

    // Get and return conversation ID
    try {
      return int.parse(response.getObject()["conversationsID"][0].toString());
    } catch (e) {
      e.toString();
      return null;
    }
  }

  /// Asynchronously get the name fo the conversation
  ///
  /// Unlike the synchronous method, this method does not need information
  /// about the members of the conversation
  ///
  /// Returns null in case of failure
  static Future<String> getConversationNameAsync(
      Conversation conversation) async {
    if (conversation.hasName) return conversation.name;

    //Get information about the members of the conversation
    final members = await UsersHelper().getUsersInfo(conversation.members);

    if (members == null) return null;

    return ConversationsHelper.getConversationName(conversation, members);
  }

  /// Turn an API entry into a [Conversation] object
  Conversation _apiToConversation(Map<String, dynamic> map) {
    return Conversation(
      id: map["ID"],
      ownerID: map["ID_owner"],
      lastActive: map["last_active"],
      name: map["name"] == false ? null : map["name"],
      following: map["following"] == 1,
      sawLastMessage: map["saw_last_message"] == 1,
      members: List<int>.from(map["members"]),
    );
  }

  /// Parse a list of messages given by the server
  Future<ConversationMessagesList> _parseConversationMessageFromServer(
      int conversationID, APIResponse response) async {
    if (response.code != 200) return null;

    // Parse the response of the server
    ConversationMessagesList list = ConversationMessagesList();
    response.getArray().forEach((f) {
      list.add(
        apiToConversationMessage(f),
      );
    });

    // Save messages in the cache
    _conversationMessagesDatabaseHelper.insertOrUpdateAll(list);

    return list;
  }

  /// Refresh the list of messages of a conversation
  ///
  /// Set [lastMessageID] to 0 to specify that we do not have any message of the
  /// conversation yet or another value else
  Future<ConversationMessagesList> _downloadNewMessagesSingle(
      int conversationID,
      {int lastMessageID = 0}) async {
    // Execute the request on the server
    final response = await APIRequest(
        uri: "conversations/refresh_single",
        needLogin: true,
        args: {
          "conversationID": conversationID.toString(),
          "last_message_id": lastMessageID.toString()
        }).exec();

    return await _parseConversationMessageFromServer(conversationID, response);
  }

  /// Get older messages for a given conversation from an online source
  Future<ConversationMessagesList> getOlderMessages({
    @required int conversationID,
    @required int oldestMessagesID,
    int limit = 15,
  }) async {
    // Perform the request online
    final response = await APIRequest(
        uri: "conversations/get_older_messages",
        needLogin: true,
        args: {
          "conversationID": conversationID.toString(),
          "oldest_message_id": oldestMessagesID.toString(),
          "limit": limit.toString()
        }).exec();

    return await _parseConversationMessageFromServer(conversationID, response);
  }

  /// Get new messages for a given conversation
  ///
  /// If [lastMessageID] is set to 0 then we retrieve the last messages of
  /// the conversation.
  /// Otherwise [lastMessageID] contains the ID of the last known message
  Future<ConversationMessagesList> getNewMessages(
      {@required int conversationID,
      int lastMessageID = 0,
      bool online = true}) async {
    if (online)
      return await _downloadNewMessagesSingle(conversationID,
          lastMessageID: lastMessageID);
    else
      return await _conversationMessagesDatabaseHelper
          .getAllMessagesConversations(conversationID,
              lastMessageID: lastMessageID);
  }

  /// Get a single conversation message from the local database
  ///
  /// Returns the message if found or null in case of failure
  Future<ConversationMessage> getSingleMessageFromCache(int messageID) async {
    return await _conversationMessagesDatabaseHelper.get(messageID);
  }

  /// Send a new message to the server
  Future<SendMessageResult> sendMessage(NewConversationMessage message) async {
    final request = APIRequest(
      uri: "conversations/sendMessage",
      needLogin: true,
      args: {
        "conversationID": message.conversationID.toString(),
        "message": message.hasMessage ? message.message : ""
      },
    );

    //Check for image
    if (message.hasImage) request.addFile("image", message.image);

    //Send the message
    APIResponse response;
    if (!message.hasImage)
      response = await request.exec();
    else
      response = await request.execWithFiles();

    if (response.code == 401)
      return SendMessageResult.MESSAGE_REJECTED;
    else if (response.code != 200) return SendMessageResult.FAILED;

    return SendMessageResult.SUCCESS;
  }

  /// Save / Update a  message into the database
  Future<void> saveMessage(ConversationMessage msg) async {
    await _conversationMessagesDatabaseHelper.insertOrUpdate(msg);
  }

  /// Remove a message from the database
  Future<void> removeMessage(int msgID) async {
    await _conversationMessagesDatabaseHelper.delete(msgID);
  }

  /// Update a message content
  Future<bool> updateMessage(int id, String newContent) async {
    final response = await APIRequest(
        uri: "conversations/updateMessage",
        needLogin: true,
        args: {"messageID": id.toString(), "content": newContent}).exec();

    if (response.code != 200) return false;

    return true;
  }

  /// Delete permanently a message specified by its [id]
  Future<bool> deleteMessage(int id) async {
    // Delete the message online
    final response = await APIRequest(
        uri: "conversations/deleteMessage",
        needLogin: true,
        args: {"messageID": id.toString()}).exec();

    if (response.code != 200) return false;

    return true;
  }

  /// Register a conversation : ask the server to notify about updates to the
  /// conversation through WebSocket
  Future<void> registerConversationEvents(int id) async {
    if (_registeredConversations.containsKey(id))
      _registeredConversations[id]++;
    else {
      _registeredConversations[id] = 1;
      await ws("\$main/register_conv", {"convID": id});
    }
  }

  /// Un-register to conversation update events
  Future<void> unregisterConversationEvents(int id) async {
    if (!_registeredConversations.containsKey(id)) return;

    _registeredConversations[id]--;

    if (_registeredConversations[id] <= 0) {
      _registeredConversations.remove(id);
      await ws("\$main/unregister_conv", {"convID": id});
    }
  }

  /// Turn an API response into a ConversationMessage object
  static ConversationMessage apiToConversationMessage(
    Map<String, dynamic> map,
  ) {
    return ConversationMessage(
      id: map["ID"],
      conversationID: map["convID"],
      userID: map["ID_user"],
      timeInsert: map["time_insert"],
      message: DisplayedString(map["message"]),
      imageURL: map["image_path"],
    );
  }
}