import {
  Plugin,
  Configurable,
  EventListener,
  InjectService
} from '@squeebot/core/lib/plugin';

import util from 'util';

import Discord, { ClientUser, Intents, Permissions, TextChannel, User } from 'discord.js';

import { logger } from '@squeebot/core/lib/core';
import { thousandsSeparator, timeSince, toHHMMSS } from '@squeebot/core/lib/common';
import {
  EMessageType,
  Formatter,
  IMessage,
  IMessageTarget,
  MarkdownFormatter,
  Protocol
} from '@squeebot/core/lib/types';

class DiscordFormatter extends MarkdownFormatter {
  public compose(objs: any): any {
    const embed = new Discord.MessageEmbed();

    for (const i in objs) {
      const elem = objs[i];

      const elemType = elem[0];
      let elemValue = elem[1];
      const elemParams = elem[2];

      if (!elemValue || (elemType !== 'field' && elemType !== 'bold')) {
        continue;
      }

      // Special types
      if (elemParams?.type) {
        switch (elemParams.type) {
          case 'time':
            elemValue = new Date(elemValue).toString();
            break;
          case 'metric':
            elemValue = thousandsSeparator(elemValue);
            break;
          case 'timesince':
            elemValue = timeSince(elemValue);
            break;
          case 'duration':
            elemValue = toHHMMSS(elemValue);
            break;
        }
      }

      if (elemParams?.type === 'description') {
        embed.setDescription(embed.description
          ? embed.description += `\n${elemValue}`
          : elemValue
        );
        continue;
      }

      if (elemParams?.type === 'title') {
        embed.setTitle(elemValue);
        if (elemParams.color) {
          embed.setColor(elemParams.color.toUpperCase());
        }
        continue;
      }

      if (elemParams?.label) {
        let label = elemParams.label;

        // If the label param is an array, choose the last element
        // The last element is generally the text version, as opposed to
        // the first element being an icon.
        if (typeof label === 'object') {
          label = elemParams.label[elemParams.label.length - 1];
        }

        embed.addField(label, elemValue, true);
      } else {
        embed.setDescription(embed.description
          ? embed.description += `\n${elemValue}`
          : elemValue
        );
      }
    }

    // May return an object, but your protocol must support it.
    return embed;
  }
}

class DiscordMessageAdapter implements IMessage {
  public time: Date = new Date();
  public resolved = false;
  public direct = false;

  constructor(
    public type: EMessageType,
    public data: any,
    public source: Protocol,
    public sender: IMessageTarget,
    public target?: IMessageTarget) {}

  public get fullSenderID(): string {
    return this.source.fullName + '/' + this.sender.id;
  }

  public get fullRoomID(): string {
    if (!this.target) {
      return this.source.fullName;
    }

    if (this.target.server) {
      return this.source.fullName + '/s:' + this.target.server + '/' + this.target.id;
    }

    return this.source.fullName + '/' + this.target.id;
  }

  public get text(): string {
    return this.data.content;
  }

  public resolve(...args: any[]): void {
    this.resolved = true;
    this.source.resolve(this, ...args);
  }

  public reject(error: Error): void {
    this.resolved = true;
    this.source.resolve(this, error.message);
  }

  public mention(user: IMessageTarget): string {
    return `<@${user.id}>`;
  }
}

class DiscordProtocol extends Protocol {
  public format: Formatter = new DiscordFormatter();
  public type = 'DiscordProtocol';

  private client = new Discord.Client({
    intents: [
      Intents.FLAGS.GUILDS,
      Intents.FLAGS.GUILD_MESSAGES,
      Intents.FLAGS.GUILD_MESSAGE_REACTIONS,
      Intents.FLAGS.GUILD_PRESENCES,
      Intents.FLAGS.GUILD_VOICE_STATES,
      Intents.FLAGS.GUILD_BANS,
      Intents.FLAGS.DIRECT_MESSAGES,
      Intents.FLAGS.DIRECT_MESSAGE_REACTIONS,
      Intents.FLAGS.DIRECT_MESSAGE_TYPING,
    ],
    partials: ['CHANNEL', 'GUILD_MEMBER', 'MESSAGE', 'USER'],
  });

  private eventsAttached = false;

  public start(...args: any[]): void {
    this.running = true;
    this.client.once('ready', () => {
      if (this.client.user) {
        this.me.id = this.client.user.id;
        this.me.name = this.client.user.username;
      }
    });

    this.attachEvents();

    this.client.on('error', (e: Error) => {
      this.emit('error', e.message);
    });
    this.client.on('disconnect', () => this.stop(true));

    this.client.login(this.config.token)
      .then(() => this.emit('running'),
      (reason) => {
        this.emit('error', reason);
        this.stop(true);
      });
  }

  public stop(force = false): void {
    if (!this.running) {
      return;
    }

    this.running = false;
    this.stopped = true;

    this.client.destroy();

    if (force) {
      this.failed = true;
    }

    this.emit('stopped');
  }

  private attachEvents(): void {
    if (this.eventsAttached) {
      return;
    }

    this.eventsAttached = true;

    this.client.on('error', (e: Error) => {
      this.emit('error', e.message);
    });

    this.client.on('disconnect', () => this.stop(true));

    this.client.on('messageCreate', (message) => {
      if (this.me && this.me.id && message.author.id === this.me.id) {
        return;
      }
      const chanName = 'name' in message.channel ? message.channel.name : message.author.username;
      const msg = new DiscordMessageAdapter(EMessageType.message,
        message,
        this,
        { name: message.author.username, id: message.author.id },
        { name: chanName, id: message.channel.id, server: message.guildId || undefined });
      this.plugin.stream.emitTo('channel', 'message', msg);
    });

    this.client.on('guildMemberAdd', (member) => {
      if (this.me && this.me.id && member.user.id === this.me.id) {
        return;
      }
      const newMessage = new DiscordMessageAdapter(
        EMessageType.roomJoin,
        member,
        this,
        { id: member.user.id, name: member.user.username },
        { server: member.guild.id, id: '*', name: '*'});
      this.plugin.stream.emitTo('channel', 'event', newMessage);
    });

    this.client.on('guildMemberRemove', (member) => {
      if (!member.user) {
        return;
      }
      if (this.me && this.me.id && member.user.id === this.me.id) {
        return;
      }
      const newMessage = new DiscordMessageAdapter(
        EMessageType.roomLeave,
        member,
        this,
        { id: member.user.id, name: member.user.username },
        { server: member.guild.id, id: '*', name: '*'});
      this.plugin.stream.emitTo('channel', 'event', newMessage);
    });
  }

  public resolve(msg: DiscordMessageAdapter, ...data: any[]): void {
    const toDiscord = this.fromSend(...data);

    if (!toDiscord) {
      return;
    }

    // Check send permission
    if (msg.data.guildId) {
      const perms = msg.data.channel.permissionsFor(this.client.user as ClientUser);
      if (perms && !perms.has(Permissions.FLAGS.SEND_MESSAGES, true)) {
        return;
      }
    }

    msg.data.channel.send(toDiscord).catch((e: Error) => {
      logger.error(e);
    });
  }

  public async sendTo(target: string, ...data: any[]): Promise<boolean> {
    const rxSplit = target.split('/');
    if (rxSplit[0] !== 'discord' || rxSplit[1] !== this.name) {
      // Invalid protocol, we do not want this!;
      return false;
    }

    const toDiscord = this.fromSend(...data);
    if (!toDiscord) {
      return false;
    }

    let channel: TextChannel | User | null = null;
    // Message to guild
    if (rxSplit.length === 4) {
      // Fetch the guild and ensure it's available
      const guildId = rxSplit[2].substring(2);
      const guild = await this.client.guilds.fetch(guildId);
      if (!guild || !guild.available || !guild.channels) {
        return false;
      }

      // Fetch the channel and ensure we can send to it
      const channelId = rxSplit[3];
      channel = await guild.channels.fetch(channelId) as TextChannel;
      if (!channel || !(channel.isText || channel.isThread) || !channel.viewable) {
        return false;
      }

      // Check send permission
      const perms = channel.permissionsFor(this.client.user as ClientUser);
      if (perms) {
        if (!perms.has(Permissions.FLAGS.SEND_MESSAGES, true)) {
          return false;
        }
      }

    // Message to user
    } else if (rxSplit.length === 3) {
      const userId = rxSplit[2];
      channel = await this.client.users.fetch(userId);
      if (!channel) {
        return false;
      }
    } else {
      return false;
    }

    await channel!.send(toDiscord);
    return true;
  }

  private fromSend(...data: any[]): { embeds?: object[]; content?: string } | null {
    let response = util.format(data[0], ...data.slice(1));
    if (!response) {
      return null;
    }

    if (Array.isArray(data[0])) {
      try {
        response = this.format.compose(data[0]);
      } catch (e: any) {
        logger.error('[%s] Failed to compose message:', this.fullName, e.message);
        return null;
      }
    }
    // Discord supports sending objects to the channel for things like embeds
    else if (typeof data[0] === 'object') {
      response = data[0];
    }

    const toDiscord: { embeds?: object[]; content?: string } = {};
    if (typeof response === 'object') {
      toDiscord.embeds = [ response ];
    } else {
      toDiscord.content = response;
    }

    return toDiscord;
  }
}

@InjectService(DiscordProtocol)
@Configurable({instances: []})
class DiscordServicePlugin extends Plugin {
  initialize(): void {
    const protoList = this.validateConfiguration();
    this.startAll(protoList);
  }

  private startAll(list: any[]): void {
    for (const ins of list) {
      const newProto = new DiscordProtocol(this, ins);
      logger.log('[%s] Starting Discord service "%s".', this.name, ins.name);
      this.monitor(newProto);
      this.service?.use(newProto, true);
    }
  }

  private monitor(proto: Protocol): void {
    proto.on('running', () => this.emit('protocolNew', proto));
    proto.on('stopped', () => this.emit('protocolExit', proto));
  }

  private validateConfiguration(): any[] {
    if (!this.config.config.instances) {
      throw new Error('Configuration incomplete!');
    }

    const instances = this.config.config.instances;
    const runnables: any[] = [];
    for (const ins of instances) {
      if (ins.enabled === false) {
        continue;
      }

      if (!ins.name || !ins.token) {
        throw new Error('Invalid instance configuration!');
      }

      runnables.push(ins);
    }

    return runnables;
  }

  @EventListener('pluginUnload')
  public unloadEventHandler(plugin: string | Plugin): void {
    if (plugin === this.name || plugin === this) {
      this.config.save().then(() =>
        this.service?.stopAll().then(() =>
        this.emit('pluginUnloaded', this)));
    }
  }
}

module.exports = DiscordServicePlugin;