import EventEmitter from 'events';
import renderAvatar from '../../app/atoms/avatar/render';
import { cssColorMXID } from '../../util/colorMXID';
import { selectRoom } from '../action/navigation';
import cons from './cons';
import navigation from './navigation';
import settings from './settings';

function isNotifEvent(mEvent) {
  const eType = mEvent.getType();
  if (!cons.supportEventTypes.includes(eType)) return false;
  if (eType === 'm.room.member') return false;

  if (mEvent.isRedacted()) return false;
  if (mEvent.getRelation()?.rel_type === 'm.replace') return false;

  return true;
}

function isMutedRule(rule) {
  return rule.actions[0] === 'dont_notify' && rule.conditions[0].kind === 'event_match';
}

function findMutedRule(overrideRules, roomId) {
  return overrideRules.find((rule) => (
    rule.rule_id === roomId
    && isMutedRule(rule)
  ));
}

class Notifications extends EventEmitter {
  constructor(roomList) {
    super();

    this.matrixClient = roomList.matrixClient;
    this.roomList = roomList;

    this.roomIdToNoti = new Map();

    this._initNoti();
    this._listenEvents();

    // Ask for permission by default after loading
    window.Notification?.requestPermission();

    // TODO:
    window.notifications = this;
  }

  _initNoti() {
    const addNoti = (roomId) => {
      const room = this.matrixClient.getRoom(roomId);
      if (this.getNotiType(room.roomId) === cons.notifs.MUTE) return;
      if (this.doesRoomHaveUnread(room) === false) return;

      const total = room.getUnreadNotificationCount('total');
      const highlight = room.getUnreadNotificationCount('highlight');
      this._setNoti(room.roomId, total ?? 0, highlight ?? 0);
    };
    [...this.roomList.rooms].forEach(addNoti);
    [...this.roomList.directs].forEach(addNoti);
  }

  doesRoomHaveUnread(room) {
    const userId = this.matrixClient.getUserId();
    const readUpToId = room.getEventReadUpTo(userId);
    const liveEvents = room.getLiveTimeline().getEvents();

    if (liveEvents[liveEvents.length - 1]?.getSender() === userId) {
      return false;
    }

    for (let i = liveEvents.length - 1; i >= 0; i -= 1) {
      const event = liveEvents[i];
      if (event.getId() === readUpToId) return false;
      if (isNotifEvent(event)) return true;
    }
    return true;
  }

  getNotiType(roomId) {
    const mx = this.matrixClient;
    let pushRule;
    try {
      pushRule = mx.getRoomPushRule('global', roomId);
    } catch {
      pushRule = undefined;
    }

    if (pushRule === undefined) {
      const overrideRules = mx.getAccountData('m.push_rules')?.getContent()?.global?.override;
      if (overrideRules === undefined) return cons.notifs.DEFAULT;

      const isMuted = findMutedRule(overrideRules, roomId);

      return isMuted ? cons.notifs.MUTE : cons.notifs.DEFAULT;
    }
    if (pushRule.actions[0] === 'notify') return cons.notifs.ALL_MESSAGES;
    return cons.notifs.MENTIONS_AND_KEYWORDS;
  }

  getNoti(roomId) {
    return this.roomIdToNoti.get(roomId) || { total: 0, highlight: 0, from: null };
  }

  getTotalNoti(roomId) {
    const { total } = this.getNoti(roomId);
    return total;
  }

  getHighlightNoti(roomId) {
    const { highlight } = this.getNoti(roomId);
    return highlight;
  }

  getFromNoti(roomId) {
    const { from } = this.getNoti(roomId);
    return from;
  }

  hasNoti(roomId) {
    return this.roomIdToNoti.has(roomId);
  }

  deleteNoti(roomId) {
    if (this.hasNoti(roomId)) {
      const noti = this.getNoti(roomId);
      this._deleteNoti(roomId, noti.total, noti.highlight);
    }
  }

  _setNoti(roomId, total, highlight) {
    const addNoti = (id, t, h, fromId) => {
      const prevTotal = this.roomIdToNoti.get(id)?.total ?? null;
      const noti = this.getNoti(id);

      noti.total += t;
      noti.highlight += h;

      if (fromId) {
        if (noti.from === null) noti.from = new Set();
        noti.from.add(fromId);
      }
      this.roomIdToNoti.set(id, noti);
      this.emit(cons.events.notifications.NOTI_CHANGED, id, noti.total, prevTotal);
    };

    const noti = this.getNoti(roomId);
    const addT = total - noti.total;
    const addH = highlight - noti.highlight;
    if (addT < 0 || addH < 0) return;

    addNoti(roomId, addT, addH);
    const allParentSpaces = this.roomList.getAllParentSpaces(roomId);
    allParentSpaces.forEach((spaceId) => {
      addNoti(spaceId, addT, addH, roomId);
    });
  }

  _deleteNoti(roomId, total, highlight) {
    const removeNoti = (id, t, h, fromId) => {
      if (this.roomIdToNoti.has(id) === false) return;

      const noti = this.getNoti(id);
      const prevTotal = noti.total;
      noti.total -= t;
      noti.highlight -= h;
      if (noti.total < 0) {
        noti.total = 0;
        noti.highlight = 0;
      }
      if (fromId && noti.from !== null) {
        if (!this.hasNoti(fromId)) noti.from.delete(fromId);
      }
      if (noti.from === null || noti.from.size === 0) {
        this.roomIdToNoti.delete(id);
        this.emit(cons.events.notifications.FULL_READ, id);
        this.emit(cons.events.notifications.NOTI_CHANGED, id, null, prevTotal);
      } else {
        this.roomIdToNoti.set(id, noti);
        this.emit(cons.events.notifications.NOTI_CHANGED, id, noti.total, prevTotal);
      }
    };

    removeNoti(roomId, total, highlight);
    const allParentSpaces = this.roomList.getAllParentSpaces(roomId);
    allParentSpaces.forEach((spaceId) => {
      removeNoti(spaceId, total, highlight, roomId);
    });
  }

  async _displayPopupNoti(mEvent, room) {
    if (!settings.showNotifications && !settings.isNotificationSounds) return;

    const actions = this.matrixClient.getPushActionsForEvent(mEvent);
    if (!actions?.notify) return;

    if (navigation.selectedRoomId === room.roomId && document.visibilityState === 'visible') return;

    if (mEvent.isEncrypted()) {
      await mEvent.attemptDecryption(this.matrixClient.crypto);
    }

    if (settings.showNotifications) {
      let title;
      if (!mEvent.sender || room.name === mEvent.sender.name) {
        title = room.name;
      } else if (mEvent.sender) {
        title = `${mEvent.sender.name} (${room.name})`;
      }

      const iconSize = 36;
      const icon = await renderAvatar({
        text: mEvent.sender.name,
        bgColor: cssColorMXID(mEvent.getSender()),
        imageSrc: mEvent.sender?.getAvatarUrl(this.matrixClient.baseUrl, iconSize, iconSize, 'crop'),
        size: iconSize,
        borderRadius: 8,
        scale: 8,
      });

      const noti = new window.Notification(title, {
        body: mEvent.getContent().body,
        icon,
        silent: settings.isNotificationSounds,
      });
      if (settings.isNotificationSounds) {
        noti.onshow = () => this._playNotiSound();
      }
      noti.onclick = () => selectRoom(room.roomId, mEvent.getId());
    } else {
      this._playNotiSound();
    }
  }

  _playNotiSound() {
    if (!this._notiAudio) {
      this._notiAudio = document.getElementById('notificationSound');
    }
    this._notiAudio.play();
  }

  _playInviteSound() {
    if (!this._inviteAudio) {
      this._inviteAudio = document.getElementById('inviteSound');
    }
    this._inviteAudio.play();
  }

  _listenEvents() {
    this.matrixClient.on('Room.timeline', (mEvent, room) => {
      if (room.isSpaceRoom()) return;
      if (!isNotifEvent(mEvent)) return;

      const liveEvents = room.getLiveTimeline().getEvents();

      const lastTimelineEvent = liveEvents[liveEvents.length - 1];
      if (lastTimelineEvent.getId() !== mEvent.getId()) return;
      if (mEvent.getSender() === this.matrixClient.getUserId()) return;

      const total = room.getUnreadNotificationCount('total');
      const highlight = room.getUnreadNotificationCount('highlight');

      if (this.getNotiType(room.roomId) === cons.notifs.MUTE) {
        this.deleteNoti(room.roomId, total ?? 0, highlight ?? 0);
        return;
      }

      this._setNoti(room.roomId, total ?? 0, highlight ?? 0);

      if (this.matrixClient.getSyncState() === 'SYNCING') {
        this._displayPopupNoti(mEvent, room);
      }
    });

    this.matrixClient.on('accountData', (mEvent, oldMEvent) => {
      if (mEvent.getType() === 'm.push_rules') {
        const override = mEvent?.getContent()?.global?.override;
        const oldOverride = oldMEvent?.getContent()?.global?.override;
        if (!override || !oldOverride) return;

        const isMuteToggled = (rule, otherOverride) => {
          const roomId = rule.rule_id;
          const room = this.matrixClient.getRoom(roomId);
          if (room === null) return false;
          if (room.isSpaceRoom()) return false;

          const isMuted = isMutedRule(rule);
          if (!isMuted) return false;
          const isOtherMuted = findMutedRule(otherOverride, roomId);
          if (isOtherMuted) return false;
          return true;
        };

        const mutedRules = override.filter((rule) => isMuteToggled(rule, oldOverride));
        const unMutedRules = oldOverride.filter((rule) => isMuteToggled(rule, override));

        mutedRules.forEach((rule) => {
          this.emit(cons.events.notifications.MUTE_TOGGLED, rule.rule_id, true);
          this.deleteNoti(rule.rule_id);
        });
        unMutedRules.forEach((rule) => {
          this.emit(cons.events.notifications.MUTE_TOGGLED, rule.rule_id, false);
          const room = this.matrixClient.getRoom(rule.rule_id);
          if (!this.doesRoomHaveUnread(room)) return;
          const total = room.getUnreadNotificationCount('total');
          const highlight = room.getUnreadNotificationCount('highlight');
          this._setNoti(room.roomId, total ?? 0, highlight ?? 0);
        });
      }
    });

    this.matrixClient.on('Room.receipt', (mEvent, room) => {
      if (mEvent.getType() === 'm.receipt') {
        if (room.isSpaceRoom()) return;
        const content = mEvent.getContent();
        const readedEventId = Object.keys(content)[0];
        const readerUserId = Object.keys(content[readedEventId]['m.read'])[0];
        if (readerUserId !== this.matrixClient.getUserId()) return;

        this.deleteNoti(room.roomId);
      }
    });

    this.matrixClient.on('Room.myMembership', (room, membership) => {
      if (membership === 'leave' && this.hasNoti(room.roomId)) {
        this.deleteNoti(room.roomId);
      }
      if (membership === 'invite') {
        this._playInviteSound();
      }
    });
  }
}

export default Notifications;