import {
  IRCCommunicator,
  IRCConnector,
  IRCConnectorConstructor,
} from './types/impl.interface';
import { IIRCLine, IIRCOptions, IQueue } from './types/irc.interfaces';
import { Collector, WhoisCollector } from './utility/collector';
import { parse } from './utility/parser';
import { SimpleEventEmitter } from './utility/simple-event-emitter';
import { parseWhois, WhoisResponse } from './utility/whois-parser';

const encodeBase64 = (input: string) => {
  if (window !== undefined && btoa !== undefined) {
    return btoa(input);
  } else if (Buffer !== undefined) {
    return Buffer.from(input).toString('base64');
  }
  return input;
};

export class IRCConnectionWrapper
  extends SimpleEventEmitter
  implements IRCCommunicator
{
  public channels: string[] = [];
  public queue: IQueue[] = [];
  public authenticated = false;
  public serverData: { [key: string]: any } = {
    name: '',
    supportedModes: {},
    serverSupports: {},
  };

  private connection?: IRCConnector;

  private _supportsDone = false;
  private _lastLineWasSupports = false;

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

  write(format: string, ...args: any[]): void {
    this.connection?.write(format, ...args);
  }

  private handlers(): void {
    this.on('authenticated', () => {
      if (this.options.channels?.length) {
        this.joinMissingChannels(this.options.channels);
      }
    });
  }

  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 * :%s',
      this.options.username,
      this.options.realname || 'realname',
    );
    this.write('NICK %s', this.options.nick);
  }

  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.untracked) {
          if (entry.await && line.command === entry.await) {
            if (
              ((entry.from &&
                line.user.nickname.toLowerCase() ===
                  entry.from.toLowerCase()) ||
                !entry.from) &&
              entry.do
            ) {
              skipHandling = true;
              entry.do(line, entry.buffer);
              return;
            }
          }

          if (
            entry.additional &&
            entry.additional.includes(line.command) &&
            entry.digest
          ) {
            skipHandling = true;
            entry.digest(line);
          }
        }

        afterModifyQueue.push(entry);
      });

      this.queue = afterModifyQueue;

      if (skipHandling) {
        return;
      }
    }

    if (
      this._lastLineWasSupports &&
      !this._supportsDone &&
      line.command !== '005'
    ) {
      this._lastLineWasSupports = false;
      this._supportsDone = true;
      this.emit('supported-modes', this.serverData.supportedModes);
      this.emit('server-supports', this.serverData.serverSupports);
    }

    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 = encodeBase64(
          this.options.nick +
            '\x00' +
            this.options.username +
            '\x00' +
            this.options.password,
        );
        this.write('AUTHENTICATE %s', authline);
        break;
      }
      case '353': {
        const isUpQueued = this.queue.find(
          (item) => item.await === '366' && item.from === line.arguments![2],
        );

        if (isUpQueued) {
          isUpQueued.buffer.push(line);
        } else {
          this.queue.push({
            untracked: true,
            from: line.arguments![2],
            await: '366',
            additional: ['353'],
            buffer: [line],
            do: (bline, data) => {
              this.emit('names', {
                channel: bline.arguments![1],
                list: [
                  ...data.map((cline: IIRCLine) =>
                    (cline.trailing || '').split(' '),
                  ),
                ].flat(),
              });
            },
          });
        }
        break;
      }
      case '366': {
        const isUpQueued = this.queue.find(
          (item) => item.await === '366' && item.from === line.arguments![1],
        );
        if (isUpQueued) {
          isUpQueued.do(line, isUpQueued.buffer);
          this.queue.splice(this.queue.indexOf(isUpQueued), 1);
        }
        break;
      }
      case '433':
        const newNick = this.options.nick + '_';
        this.write('NICK %s', newNick);
        this.options.nick = newNick;
        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', {
          type: line.command.toLowerCase(),
          message: line.trailing,
          to: line.arguments?.[0],
          nickname: line.user.nickname,
          raw: line,
        });
        break;
      case '001':
        if (!this.authenticated) {
          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] || this.options.nick;
          this.authenticated = true;
          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': {
        this._lastLineWasSupports = true;
        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 '321':
        this.emit('channel-list-item', {
          channel: 'Channel',
          users: 'Users',
          topic: 'Topic',
        });
        break;
      case '322':
        this.emit('channel-list-item', {
          channel: line.arguments![1],
          users: line.arguments![2],
          topic: line.trailing,
        });
        break;
      case 'quit':
        if (line.user.nickname !== this.options.nick) {
          this.emit('leave', {
            nickname: line.user.nickname,
          });
        }
        break;
      case 'nick':
        if (line.user.nickname === this.options.nick) {
          this.options.nick = line.arguments?.[0] || 'unknown';
        }
        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 'mode':
        let isChannelMode = false;
        let method = '+';
        let lts = line.trailing ? line.trailing.split(' ') : [];
        if (line.arguments![0].indexOf('#') !== -1) {
          isChannelMode = true;
        }

        let modes: string | string[] = line.arguments![1];

        if (!modes && line.trailing !== '') {
          modes = line.trailing!;
        }

        let sender = line.user.nickname;
        if (sender === '') {
          sender = line.user.hostname;
        }

        method = modes.substring(0, 1);
        modes = modes.substring(1).split('');
        let pass = [];

        if (isChannelMode) {
          for (let i in modes) {
            let mode = modes[i];
            let modei = parseInt(i);
            if (this.serverData.supportedModes[mode]) {
              this.emit('channel-mode', {
                type: method,
                mode: mode,
                modeTarget: line.arguments![2]
                  ? line.arguments![2 + modei]
                    ? line.arguments![2 + modei]
                    : lts[modei - 1]
                  : lts[modei],
                ...line,
              });
            } else {
              pass.push(mode);
            }
          }
        } else {
          pass = modes;
        }

        if (pass.length > 0) {
          this.emit('user-mode', {
            type: method,
            mode: pass.join(''),
            modeTarget: line.arguments![0],
            ...line,
          });
        }
        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) });
        if (!this.authenticated) {
          this.connection?.destroy();
          this.connection = undefined;
        }
        break;
    }
  }

  public async connect(): Promise<void> {
    if (this.connection) {
      await this.connection.destroy();
    }

    this.connection = new this.connector(
      this.options.ssl ?? false,
      this.options.host,
      this.options.port,
    );

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

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

    this.connection.on('data', (line: string) => {
      const parsedLine = parse(line);
      this.emit('line', parsedLine);
      this.handleServerLine(parsedLine);
    });

    await this.connection.connect();

    this.authenticate();
  }

  public async disconnect(reason?: string): Promise<void> {
    if (!this.connected) {
      if (this.connection) {
        await this.connection.destroy();
      }
      return;
    }

    this.write('QUIT :%s', reason || 'Client exiting');

    // Wait for exit
    return new Promise((resolve) => {
      const interval = setInterval(() => {
        if (!this.connected) {
          clearInterval(interval);
          resolve();
        }
      }, 100);
    });
  }

  public get connected() {
    return this.connection?.connected ?? false;
  }

  public async getPing(): Promise<number> {
    return new Promise<number>((resolve) => {
      const sendTime = Date.now();

      this.useCollector(
        new Collector('PONG', (line) => {
          resolve(Date.now() - sendTime);
        }),
        'PING :%s',
        this.serverData.name,
      );
    });
  }

  public async whois(nick: string): Promise<WhoisResponse> {
    return new Promise((resolve) => {
      this.useCollector(
        new WhoisCollector((data) => resolve(parseWhois(data))),
        'WHOIS %s',
        nick,
      );
    });
  }

  public useCollector(collector: IQueue, line: string, ...args: any[]) {
    this.queue.push(collector);
    this.write(line, ...args);
  }
}