import 'dart:typed_data';

import 'package:comunic/lists/group_members_list.dart';
import 'package:comunic/lists/groups_list.dart';
import 'package:comunic/models/advanced_group_info.dart';
import 'package:comunic/models/api_request.dart';
import 'package:comunic/models/group.dart';
import 'package:comunic/models/group_membership.dart';
import 'package:comunic/utils/api_utils.dart';
import 'package:comunic/utils/map_utils.dart';

/// Groups helper
///
/// @author Pierre HUBERT

const _APIGroupsMembershipLevelsMap = {
  "administrator": GroupMembershipLevel.ADMINISTRATOR,
  "moderator": GroupMembershipLevel.MODERATOR,
  "member": GroupMembershipLevel.MEMBER,
  "invited": GroupMembershipLevel.INVITED,
  "pending": GroupMembershipLevel.PENDING,
  "visitor": GroupMembershipLevel.VISITOR
};

const _APIGroupsVisibilityLevelsMap = {
  "open": GroupVisibilityLevel.OPEN,
  "private": GroupVisibilityLevel.PRIVATE,
  "secrete": GroupVisibilityLevel.SECRETE
};

const _APIGroupsRegistrationLevelsMap = {
  "open": GroupRegistrationLevel.OPEN,
  "moderated": GroupRegistrationLevel.MODERATED,
  "closed": GroupRegistrationLevel.CLOSED
};

const _APIGroupsPostsCreationLevelsMap = {
  "moderators": GroupPostCreationLevel.MODERATORS,
  "members": GroupPostCreationLevel.MEMBERS
};

final _groupsListCache = GroupsList();

/// Callback for getting advanced user information
enum GetAdvancedInfoStatus { SUCCESS, ACCESS_DENIED }

class GetAdvancedInfoResult {
  final GetAdvancedInfoStatus status;
  final AdvancedGroupInfo info;

  GetAdvancedInfoResult(this.status, this.info) : assert(status != null);
}

/// Groups helper
class GroupsHelper {
  /// Download a list of groups information from the server
  Future<GroupsList> _downloadList(Set<int> groups) async {
    final response = await APIRequest(
      uri: "groups/get_multiple_info",
      needLogin: true,
      args: {"list": groups.join(",")},
    ).exec();

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

    final list = GroupsList();

    response
        .getObject()
        .forEach((k, d) => list[int.parse(k)] = _getGroupFromAPI(d));

    return list;
  }

  /// Get a list of groups from the server. In case of error, this method throws
  /// an exception
  Future<GroupsList> getListOrThrow(Set<int> groups,
      {bool force = false}) async {
    final list = await getList(groups, force: force);

    if (list == null) throw Exception("Could not get the list of groups!");

    return list;
  }

  /// Get a list of groups from the server
  Future<GroupsList> getList(Set<int> groups, {bool force = false}) async {
    final list = GroupsList();

    // Check which groups information to download
    final toDownload = Set<int>();
    groups.forEach((groupID) {
      if (!force && _groupsListCache.containsKey(groupID))
        list[groupID] = _groupsListCache[groupID];
      else
        toDownload.add(groupID);
    });

    // Download required groups information
    if (toDownload.length > 0) {
      final downloaded = await _downloadList(toDownload);

      if (downloaded == null) return null;

      list.addAll(downloaded);
      _groupsListCache.addAll(downloaded);
    }

    return list;
  }

  /// Get information about a single group
  ///
  /// Throws in case of failure
  Future<Group> getSingle(int groupID, {bool force = false}) async {
    return (await getListOrThrow(Set<int>()..add(groupID), force: force))
        .values
        .first;
  }

  /// Get the list of groups of a user
  Future<Set<int>> getListUser() async =>
      (await APIRequest(uri: "groups/get_my_list", needLogin: true).exec())
          .assertOk()
          .getArray()
          .map((f) => cast<int>(f))
          .toSet();

  /// Create a new group
  ///
  /// Throws in case of failure
  static Future<int> create(String name) async {
    final result = await APIRequest.withLogin("groups/create")
        .addString("name", name)
        .execWithThrow();

    return result.getObject()["id"];
  }

  /// Perform a simple membership request
  Future<bool> _simpleMembershipRequest(int groupID, String uri,
          {Map<String, String> args}) async =>
      (await (APIRequest(uri: uri, needLogin: true)
                ..addInt("id", groupID)
                ..addArgs(args == null ? Map() : args))
              .exec())
          .isOK;

  /// Remove group membership
  Future<bool> removeMembership(int groupID) async =>
      _simpleMembershipRequest(groupID, "groups/remove_membership");

  /// Cancel membership request
  Future<bool> cancelRequest(int groupID) async =>
      _simpleMembershipRequest(groupID, "groups/cancel_request");

  /// Send a new membership request
  Future<bool> sendRequest(int groupID) async =>
      _simpleMembershipRequest(groupID, "groups/send_request");

  /// Respond to a group membership invitation
  Future<bool> respondInvitation(int groupID, bool accept) async =>
      _simpleMembershipRequest(groupID, "groups/respond_invitation", args: {
        "accept": accept ? "true" : "false",
      });

  /// Update group following status
  Future<bool> setFollowing(int groupID, bool follow) async =>
      (await (APIRequest(uri: "groups/set_following", needLogin: true)
                ..addInt("groupID", groupID)
                ..addBool("follow", follow))
              .exec())
          .isOK;

  /// Get advanced information about the user
  Future<GetAdvancedInfoResult> getAdvancedInfo(int groupID) async {
    // Get advanced information about the user
    final result =
        await (APIRequest(uri: "groups/get_advanced_info", needLogin: true)
              ..addInt("id", groupID))
            .exec();

    switch (result.code) {
      case 401:
        return GetAdvancedInfoResult(GetAdvancedInfoStatus.ACCESS_DENIED, null);

      case 200:
        return GetAdvancedInfoResult(GetAdvancedInfoStatus.SUCCESS,
            _getAdvancedGroupInfoFromAPI(result.getObject()));

      default:
        throw Exception("Could not get advanced group information!");
    }
  }

  /// Get group settings
  ///
  /// This function is currently a kind of alias, but it might
  /// change in the future
  ///
  /// Throws in case of error
  Future<AdvancedGroupInfo> getSettings(int groupID) async {
    final groupInfo = await getAdvancedInfo(groupID);

    if (groupInfo.status != GetAdvancedInfoStatus.SUCCESS)
      throw Exception("Could not get group information!");

    return groupInfo.info;
  }

  /// Check the availability of a virtual directory
  ///
  /// Throws in case of error
  static Future<void> checkVirtualDirectoryAvailability(
          int groupID, String dir) async =>
      await APIRequest(uri: "groups/checkVirtualDirectory", needLogin: true)
          .addInt("groupID", groupID)
          .addString("directory", dir)
          .execWithThrow();

  /// Update (set) new group settings
  ///
  /// Throws in case of error
  static Future<void> setSettings(AdvancedGroupInfo settings) async {
    await APIRequest(uri: "groups/set_settings", needLogin: true)
        .addInt("id", settings.id)
        .addString("name", settings.name)
        .addString("virtual_directory", settings.virtualDirectory)
        .addString("visibility",
            invertMap(_APIGroupsVisibilityLevelsMap)[settings.visibilityLevel])
        .addString(
            "registration_level",
            invertMap(
                _APIGroupsRegistrationLevelsMap)[settings.registrationLevel])
        .addString(
            "posts_level",
            invertMap(
                _APIGroupsPostsCreationLevelsMap)[settings.postCreationLevel])
        .addString("description", settings.description)
        .addString("url", settings.url)
        .execWithThrow();
  }

  /// Upload a new logo
  ///
  /// Throws in case of failure
  static Future<void> uploadNewLogo(int groupID, Uint8List bytes) async =>
      await APIRequest(uri: "groups/upload_logo", needLogin: true)
          .addInt("id", groupID)
          .addBytesFile("logo", BytesFile("logo.png", bytes))
          .execWithFilesAndThrow();

  /// Delete group logo
  ///
  /// Throws in case of error
  static Future<void> deleteLogo(int groupID) async =>
      await APIRequest(uri: "groups/delete_logo", needLogin: true)
          .addInt("id", groupID)
          .execWithThrow();

  /// Delete a group
  ///
  /// Throws in case of error
  static Future<void> deleteGroup(int groupID, String password) async =>
      await APIRequest(uri: "groups/delete", needLogin: true)
          .addInt("groupID", groupID)
          .addString("password", password)
          .execWithThrow();

  /// Get the list of members of the group
  ///
  /// Throws in case of failure
  static Future<GroupMembersList> getMembersList(int groupID) async =>
      GroupMembersList()
        ..addAll((await APIRequest(uri: "groups/get_members", needLogin: true)
                .addInt("id", groupID)
                .execWithThrow())
            .getArray()
            .map((f) => _apiToGroupMembership(f))
            .toList());

  /// Invite a user to join a group
  ///
  /// Throws an exception in case of failure
  static Future<void> sendInvitation(int groupID, int userID) async =>
      APIRequest.withLogin("groups/invite")
          .addInt("group_id", groupID)
          .addInt("userID", userID)
          .execWithThrow();

  /// Cancel a group membership invitation
  ///
  /// Throws an exception in case of failure
  static Future<void> cancelInvitation(int groupID, int userID) async =>
      await APIRequest.withLogin("groups/cancel_invitation")
          .addInt("groupID", groupID)
          .addInt("userID", userID)
          .execWithThrow();

  /// Respond to a group membership request
  ///
  /// Throws an exception in case of failure
  static Future<void> respondRequest(
          int groupID, int userID, bool accept) async =>
      await APIRequest.withLogin("groups/respond_request")
          .addInt("groupID", groupID)
          .addInt("userID", userID)
          .addBool("accept", accept)
          .execWithThrow();

  /// Remove a member from a group
  ///
  /// Throws an exception in case of failure
  static Future<void> removeMemberFromGroup(int groupID, int userID) async =>
      APIRequest.withLogin("groups/delete_member")
          .addInt("groupID", groupID)
          .addInt("userID", userID)
          .execWithThrow();

  /// Change the membership level of a member of a group
  ///
  /// Throws an exception in case of failure
  static Future<void> setNewLevel(
          int groupID, int userID, GroupMembershipLevel level) async =>
      await APIRequest.withLogin("groups/update_membership_level")
          .addInt("groupID", groupID)
          .addInt("userID", userID)
          .addString("level", invertMap(_APIGroupsMembershipLevelsMap)[level])
          .execWithThrow();

  /// Turn an API entry into a group object
  Group _getGroupFromAPI(Map<String, dynamic> map) {
    return Group(
        id: map["id"],
        name: map["name"],
        iconURL: map["icon_url"],
        numberMembers: map["number_members"],
        membershipLevel: _APIGroupsMembershipLevelsMap[map["membership"]],
        visibilityLevel: _APIGroupsVisibilityLevelsMap[map["visibility"]],
        registrationLevel:
            _APIGroupsRegistrationLevelsMap[map["registration_level"]],
        postCreationLevel: _APIGroupsPostsCreationLevelsMap[map["posts_level"]],
        virtualDirectory: nullToEmpty(map["virtual_directory"]),
        following: map["following"]);
  }

  /// Get advanced group information
  AdvancedGroupInfo _getAdvancedGroupInfoFromAPI(Map<String, dynamic> map) =>
      AdvancedGroupInfo(
        id: map["id"],
        name: map["name"],
        iconURL: map["icon_url"],
        numberMembers: map["number_members"],
        membershipLevel: _APIGroupsMembershipLevelsMap[map["membership"]],
        visibilityLevel: _APIGroupsVisibilityLevelsMap[map["visibility"]],
        registrationLevel:
            _APIGroupsRegistrationLevelsMap[map["registration_level"]],
        postCreationLevel: _APIGroupsPostsCreationLevelsMap[map["posts_level"]],
        virtualDirectory: nullToEmpty(map["virtual_directory"]),
        following: map["following"],
        timeCreate: map["time_create"],
        description: nullToEmpty(map["description"]),
        url: nullToEmpty(map["url"]),
        likes: map["number_likes"],
        userLike: map["is_liking"],
      );

  /// Create [GroupMembership] object from API entry
  static GroupMembership _apiToGroupMembership(Map<String, dynamic> row) =>
      GroupMembership(
        userID: row["user_id"],
        groupID: row["group_id"],
        timeCreate: row["time_create"],
        level: _APIGroupsMembershipLevelsMap[row["level"]],
      );
}