import util from 'util';
import tls, { TLSSocket } from 'tls';
import net, { Socket } from 'net';
import { IIRCLine, parse } from './parser';
import { EventEmitter } from 'events';
import { logger } from '@squeebot/core/lib/core';
const MAXMSGLEN = 512;

export interface IIRCOptions {
  nick: string;
  host: string;
  username?: string;
  hostname?: string;
  port?: number;
  password?: string | null;
  sasl?: boolean;
  ssl?: boolean;
  channels: string[];
  nickserv: {[key: string]: any};
}

export interface IIRCMessage {
  message: string;
  to: string;
  nickname: string;
  raw: IIRCLine;
}

export interface IQueue {
  await: string;
  from: string;
  do: (line: IIRCLine) => void;
}

export interface INickStore {
  checked: number;
  result: boolean;
}

declare type ConnectSocket = TLSSocket | Socket;

export class IRC extends EventEmitter {
  public alive = false;
  public authenticated = false;
  public serverData: { [key: string]: any } = {
    name: '',
    supportedModes: {},
    serverSupports: {},
  };

  public queue: IQueue[] = [];
  public channels: string[] = [];
  public nickservStore: { [key: string]: INickStore } = {};

  private socket: ConnectSocket | null = null;

  constructor(public options: IIRCOptions) {
    super();
    if (!this.options.username) {
      this.options.username = this.options.nick;
    }
  }

  // Chop message into pieces recursively, splitting them at lenoffset
  public static truncate(msg: string, lenoffset: number): string[] {
    let pieces: string[] = [];
    if (msg.length <= lenoffset) {
      pieces.push(msg);
    } else {
      const m1 = msg.substring(0, lenoffset);
      const m2 = msg.substring(lenoffset);
      pieces.push(m1);
      if (m2.length > lenoffset) {
        pieces = pieces.concat(IRC.truncate(m2, lenoffset));
      } else {
        pieces.push(m2);
      }
    }
    return pieces;
  }

  private authenticate(): void {
    if (this.options.sasl) {
      this.write('CAP REQ :sasl');
    }

    if (this.options.password && !this.options.sasl) {
      this.write('PASS %s', this.options.password);
    }

    this.write('USER %s 8 * :Squeebot 3.0 Core', this.options.username);
    this.write('NICK %s', this.options.nick);

    this.on('authenticated', () => {
      this.joinMissingChannels(this.options.channels);
    });

    this.on('testnick', (data: { nickname: string; func: (result: boolean) => void }) => {
      if (this.nickservStore[data.nickname] != null) {
        if (this.nickservStore[data.nickname].result === true) {
          data.func(true);
          return;
        } else {
          if (this.nickservStore[data.nickname].checked < Date.now() - 1800000) { // 30 minutes
            delete this.nickservStore[data.nickname];
          }
        }
      }

      if (this.options.nickserv
        && this.options.nickserv.enabled
        && this.options.nickserv.command
      ) {
        this.queue.push({
          await: 'NOTICE',
          from: 'NickServ',
          do: (line: IIRCLine) => {
            if (!line.trailing) {
              return data.func(false);
            }

            const splitline = line.trailing.trim().split(' ');
            const authNumber = parseInt(splitline[2], 10);

            let result = false;
            if (isNaN(authNumber)) {
              this.options.nickserv.enabled = false;
              data.func(false);
              logger.warn(`[IRC] ${this.options.host} does not seem to support NickServ ${this.options.nickserv.command}`);
              logger.warn(`[IRC] Their reply was: ${line.trailing}`);
              return;
            }
            
            if (authNumber > 0) {
              result = true;
            }

            this.nickservStore[data.nickname] = {
              result, checked: Date.now(),
            };
            data.func(result);
          }
        });
        this.write('PRIVMSG nickserv :%s %s', this.options.nickserv.command, data.nickname);
      }
    });
  }

  public disconnect(): void {
    if (!this.alive) {
      return;
    }
    this.write('QUIT :%s', 'Squeebot 3.0 Core - IRC Service');
    this.alive = false;
  }

  public write(...args: any[]): void {
    const data = util.format.apply(null, [args[0], ...args.slice(1)]);
    if (!this.alive) {
      return;
    }
    this.socket?.write(data + '\r\n');
  }

  private joinMissingChannels(arr: string[]): void {
    if (arr) {
      for (const i in arr) {
        let chan = arr[i];
        if (chan.indexOf('#') !== 0) {
          chan = '#' + chan;
        }

        if (this.channels.indexOf(chan) === -1) {
          this.write('JOIN %s', chan);
        }
      }
    }
  }

  private handleServerLine(line: IIRCLine): void {
    if (this.queue.length) {
      let skipHandling = false;
      const afterModifyQueue: IQueue[] = [];
      this.queue.forEach((entry) => {
        if (entry.await && line.command === entry.await) {
          if (entry.from && line.user.nickname.toLowerCase() === entry.from.toLowerCase()) {
            if (entry.do) {
              skipHandling = true;
              entry.do(line);
              return;
            }
          }
        }
        afterModifyQueue.push(entry);
      });

      this.queue = afterModifyQueue;

      if (skipHandling) {
        return;
      }
    }

    switch (line.command.toLowerCase()) {
    case 'cap':
      if (line.trailing === 'sasl' && line.arguments?.[1] === 'ACK' && !this.authenticated) {
        this.write('AUTHENTICATE PLAIN');
      }
      break;
    case '+':
    case ':+': {
      if (this.authenticated) {
        return;
      }

      const authline = Buffer.from(this.options.nick + '\x00' + this.options.username + '\x00' + this.options.password)
        .toString('base64');
      this.write('AUTHENTICATE %s', authline);
      break;
    }
    case '904':
      this.emit('error', {
        error: new Error(line.trailing),
        fatal: true
      });
      break;
    case '903':
      this.write('CAP END');
      break;
    case 'notice':
    case 'privmsg':
      if (!line.user.nickname || line.user.nickname === '') {
        return;
      }
      this.emit('message', {
        message: line.trailing,
        to: line.arguments?.[0],
        nickname: line.user.nickname,
        raw: line
      });
      break;
    case '001':
      this.serverData.name = line.user.hostname;
      this.authenticated = true;

      // Set nick to what the server actually thinks is our nick
      this.options.nick = line.arguments?.[0] || 'Squeebot';
      this.emit('authenticated', true);

      // Send a whois request for self in order to reliably fetch hostname of self
      this.write('WHOIS %s', this.options.nick);
      break;
    case '005': {
      if (!line.arguments) {
        break;
      }
      const argv = line.arguments?.slice(1);
      for (const entry of argv) {
        if (entry.indexOf('=') !== -1) {
          const t = entry.split('=') as string[];
          if (t[0] === 'PREFIX') {
            const d = t[1].match(/\((\w+)\)(.*)/);
            if (d) {
              const r = d[1].split('');
              const aa = d[2].split('');
              r.forEach((value, index) => {
                this.serverData.supportedModes[value] = aa[index];
              });
            }
          } else if (t[0] === 'NETWORK') {
            this.serverData.network = t[1];
          } else if (t[0] === 'CHANNELLEN') {
            this.serverData.maxChannelLength = parseInt(t[1], 10);
          }

          let numeral: string | number = t[1];
          if (!isNaN(parseInt(numeral, 10))) {
            numeral = parseInt(numeral, 10);
          }
          this.serverData.serverSupports[t[0]] = numeral;
        } else {
          this.serverData.serverSupports[entry] = true;
        }
      }
      break;
    }
    // Set hostname from 396 (non-standard)
    case '396':
      this.options.hostname = line.arguments?.[1];
      break;
      // Set hostname from self-whois
    case '311':
      if (line.arguments?.[1] !== this.options.nick) {
        return;
      }
      this.options.hostname = line.arguments?.[3];
      break;
    case 'quit':
      if (line.user.nickname !== this.options.nick) {
        if (this.nickservStore[line.user.nickname]) {
          delete this.nickservStore[line.user.nickname];
        }

        this.emit('leave', {
          nickname: line.user.nickname
        });
      }
      break;
    case 'nick':
      if (line.user.nickname === this.options.nick) {
        this.options.nick = line.arguments?.[0] || 'unknown';
      } else if (this.nickservStore[line.user.nickname]) {
        delete this.nickservStore[line.user.nickname];
      }
      this.emit('nick', {
        oldNick: line.user.nickname,
        newNick: line.arguments?.[0]
      });
      break;
    case 'join':
      if (line.user.nickname === this.options.nick && line.trailing) {
        this.channels.push(line.trailing);
      }

      this.emit('join', {
        nickname: line.user.nickname,
        channel: line.trailing
      });
      break;
    case 'part':
    case 'kick':
      if (line.user.nickname === this.options.nick && line.arguments) {
        const indexAt = this.channels.indexOf(line.arguments[0]);
        if (indexAt !== -1) {
          this.channels.splice(indexAt, 1);
        }
      }
      this.emit('leave', {
        nickname: line.user.nickname,
        channel: line.arguments?.[0]
      });
      break;
    case 'error':
      this.emit('error', { fatal: true, error: new Error(line.raw) });
      break;
    }
  }

  // Send a message with the max bytelength of 512 in mind for trailing
  public cmd(command: string, argv: string[], trailing: string): void {
    const args = argv.join(' ');
    let resolution: string[] = [];

    // Prevent newline messages from being sent as a command
    const fs = trailing.split('\n');

    // Predict the length the server is going to split at
    // :nickname!username@hostname command args :trailing\r\n
    const header = this.options.nick.length +
      (this.options.hostname || '').length +
      (this.options.username || '').length + 4 + 2;
    const offset = command.length + args.length + 3 + header;

    // Split the message up into chunks
    for (const i in fs) {
      const msg = fs[i];
      if (msg.length > MAXMSGLEN - offset) {
        resolution = resolution.concat(IRC.truncate(msg, MAXMSGLEN - offset));
      } else {
        resolution.push(msg);
      }
    }

    for (const i in resolution) {
      // Add delay to writes to prevent RecvQ overflow
      setTimeout(() => {
        this.write('%s %s :%s', command, args, resolution[i]);
      }, 1000 * parseInt(i, 10));
    }
  }

  public message(target: string, message: string): void {
    this.cmd('PRIVMSG', [target], message);
  }

  public notice(target: string, message: string): void {
    this.cmd('NOTICE', [target], message);
  }

  public connect(): void {
    if (!this.options.host || !this.options.port) {
      this.emit('error', {
        error: new Error('No host or port specified!'),
        fatal: true
      });
      return;
    }

    const opts = {
      port: this.options.port,
      host: this.options.host,
      rejectUnauthorized: false
    };

    let connection: ConnectSocket;
    const connfn = () => {
      this.alive = true;
      this.authenticate();
    };

    // For some reason, tls.connect and net.connect are not
    // compatible according to TypeScript..
    if (this.options.ssl) {
      connection = tls.connect(opts, connfn);
    } else {
      connection = net.connect(opts, connfn);
    }

    this.socket = connection;

    let buffer: any = '';
    this.socket?.on('data', (chunk) => {
      buffer += chunk;
      const data = buffer.split('\r\n');
      buffer = data.pop();

      data.forEach((line: string) => {
        if (line.indexOf('PING') === 0) {
          this.socket?.write('PONG' + line.substring(4) + '\r\n');
          return;
        }

        // Emit line as raw
        this.emit('raw', line);

        // Parse the line
        const parsed = parse(line);

        // Emit the parsed line
        this.emit('line', parsed);

        // Handle the line
        this.handleServerLine(parsed);
      });
    });

    this.socket.on('close', (data) => {
      this.alive = false;
      this.emit('disconnect', { type: 'sock_closed', raw: data, message: 'Connection closed.' });

      this.authenticated = false;
    });

    this.socket.on('error', (data) => {
      this.alive = false;
      this.emit('error', { fatal: true, error: new Error(data) });

      this.authenticated = false;
    });
  }
}