import path from 'path';
import net from 'net';
import util from 'util';
import cprog from 'child_process';
import convert from 'convert-units';

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

import { IMessage } from '@squeebot/core/lib/types';
import { httpGET, parseTimeToSeconds, readableTime } from '@squeebot/core/lib/common';

import { logger } from '@squeebot/core/lib/core';

type CEXResponse = {[key: string]: number};

const cexCache: {[key: string]: number | CEXResponse} = {
  expiry: 0,
  date: 0,
  cache: {},
};

const bases: {[key: number]: string[]} = {
  2: ['bin', 'binary'],
  8: ['oct', 'octal'],
  10: ['dec', 'decimal'],
  16: ['hex', 'hexadecimal']
};

function getBaseNum(base: string): number | null {
  let result = null;
  for (const i in bases) {
    const defs = bases[i];
    if (defs.indexOf(base) === -1) {
      continue;
    }
    result = parseInt(i, 10);
  }

  if (result) {
    return result;
  }

  if (base.indexOf('b') !== 0) {
    return null;
  }

  const matcher = base.match(/b(?:ase-?)?(\d+)/);
  if (!matcher || !matcher[1] || isNaN(parseInt(matcher[1], 10))) {
    return null;
  }
  return parseInt(matcher[1], 10);
}

const urlRegex = /(((ftp|https?):\/\/)[-\w@:%_+.~#?,&//=]+)/g;
const fork = cprog.fork;

// Run mathjs in a separate thread to avoid the killing of the main process
function opMath(expression: string, method = 'eval'): Promise<string> {
  return new Promise((resolve, reject) => {
    // Fork the script
    const mathThread = fork(path.join(__dirname, 'math.js'));

    let done = false;

    // Time the request out when user enters something too complex
    const timeItOut = setTimeout(() => {
      mathThread.kill('SIGKILL');
      done = true;
      return reject(new Error('Timed out'));
    }, 8000);

    // Send data to the thread to process
    mathThread.send(method + ' ' + expression);

    // Recieve data
    mathThread.on('message', (chunk) => {
      clearTimeout(timeItOut);

      if (done) {
        return;
      }
      const line = chunk.toString().trim();

      if (line.length > 280) {
        return reject(new Error('The response was too large'));
      }

      done = true;

      if (line === 'null') {
        return reject(new Error('Nothing was returned'));
      }

      resolve(line);
    });

    mathThread.on('exit', () => {
      clearTimeout(timeItOut);

      if (!done) {
        reject(new Error('Nothing was returned'));
      }
    });
  });
}

function rgbToHex(r: number, g: number, b: number): string {
  // tslint:disable-next-line: no-bitwise
  return '#' + ((1 << 24) + (r << 16) + (g << 8) + b).toString(16).slice(1);
}

function hexToRgb(hex: string): {[key: string]: number} | null {
  // Expand shorthand form (e.g. "03F") to full form (e.g. "0033FF")
  const shorthandRegex = /^#?([a-f\d])([a-f\d])([a-f\d])$/i;
  hex = hex.replace(shorthandRegex, (m, r, g, b) => {
    return r + r + g + g + b + b;
  });

  const result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
  return result ? {
    r: parseInt(result[1], 16),
    g: parseInt(result[2], 16),
    b: parseInt(result[3], 16)
  } : null;
}

function pingTcpServer(host: string, port: number): Promise<number> {
  return new Promise((resolve, reject) => {
    let isFinished = false;
    let timeA = new Date().getTime();
    const timeB = new Date().getTime();

    function returnResults(status: boolean, info: number | Error): void {
      if (!isFinished) {
        isFinished = true;

        if (info instanceof Error) {
          return reject(info);
        }

        resolve(info);
      }
    }

    const pingHost = net.connect({port, host}, () => {
      timeA = new Date().getTime();
      returnResults(true, timeA - timeB);
      pingHost.end();
      pingHost.destroy();
    });

    pingHost.setTimeout(5000);

    pingHost.on('timeout', () => {
      pingHost.end();
      pingHost.destroy();
      returnResults(false, new Error('timeout'));
    });

    pingHost.on('error', (e) => {
      pingHost.end();
      pingHost.destroy();
      returnResults(false, e);
    });

    pingHost.on('close', () => {
      returnResults(false, new Error('closed'));
    });
  });
}

function addCommands(plugin: UtilityPlugin, commands: any): void {
  const cmds = [];

  cmds.push({
    name: 'binary',
    execute: async (msg: IMessage, spec: any, prefix: string, ...simplified: any[]): Promise<boolean> => {
      let response = '';
      let strArr;
      let i;
      let text = msg.data.split(' ').slice(2).join(' ');

      try {
        switch (simplified[0] ? simplified[0].toUpperCase() : null) {
          case 'ENCODE':
            strArr = text.split('');

            for (i in strArr) {
              response += ' ' + ('0000000' +
                parseInt(Buffer.from(strArr[i].toString(), 'utf8').toString('hex'), 16).toString(2)).slice(-8);
            }

            response = response.substr(1);

            break;
          case 'DECODE':
            text = text.split(' ').join('');
            i = 0;

            while (8 * (i + 1) <= text.length) {
              response += Buffer.from(parseInt(text.substr(8 * i, 8), 2).toString(16), 'hex').toString('utf8');
              i++;
            }

            response = 'Decoded: ' + response.replace(/\n/g, '\\n').replace(/\r/g, '\\r');
        }
      } catch (e) {
        msg.resolve('Operation failed.');
        return true;
      }

      msg.resolve(response);
      return true;
    },
    description: 'Encode/decode binary (ASCII only)',
    usage: '<ENCODE/DECODE> <message>'
  });

  cmds.push({
    name: 'hexstr',
    execute: async (msg: IMessage, spec: any, prefix: string, ...simplified: any[]): Promise<boolean> => {
      let response = '';
      let i;
      let text = msg.data.split(' ').slice(2).join(' ');

      try {
        switch (simplified[0] ? simplified[0].toUpperCase() : null) {
          case 'DECODE':
            text = text.replace(/\s/g, '');

            for (i = 0; i < text.length; i += 2) {
              response += String.fromCharCode(parseInt(text.substr(i, 2), 16));
            }

            response = 'Decoded: ' + response.replace(/\n/g, '\\n').replace(/\r/g, '\\r');
            break;
          case 'ENCODE':
            for (i = 0; i < text.length; i++) {
              response += text.charCodeAt(i).toString(16) + ' ';
            }
            break;
        }
      } catch (e) {
        msg.resolve('Operation failed.');
        return true;
      }

      msg.resolve(response);
      return true;
    },
    description: 'Encode/decode hexadecimal (ASCII only)',
    usage: '<ENCODE/DECODE> <string>'
  });

  cmds.push({
    name: 'base64',
    execute: async (msg: IMessage, spec: any, prefix: string, ...simplified: any[]): Promise<boolean> => {
      let response = '';
      const text = msg.data.split(' ').slice(2).join(' ');

      try {
        switch (simplified[0] ? simplified[0].toUpperCase() : null) {
          case 'DECODE':
            response = 'Decoded: ' + (Buffer.from(text, 'base64').toString('ascii')).replace(/\n/g, '\\n').replace(/\r/g, '\\r');
            break;
          case 'ENCODE':
            response = Buffer.from(text).toString('base64');
            break;
        }
      } catch (e) {
        msg.resolve('Operation failed.');
        return true;
      }

      msg.resolve(response);
      return true;
    },
    description: 'Encode/decode base64 (ASCII only)',
    usage: '<ENCODE/DECODE> <string>'
  });

  cmds.push({
    name: 'numsys',
    execute: async (msg: IMessage, spec: any, prefix: string, ...simplified: any[]): Promise<boolean> => {
      const input = simplified[0];
      const src = simplified[1].toLowerCase();
      const dst = simplified[2].toLowerCase();

      const srcBase = getBaseNum(src);
      const dstBase = getBaseNum(dst);

      if (!srcBase || !dstBase || dstBase > 36 || dstBase < 2 || srcBase > 36 || srcBase < 2) {
        msg.resolve('Invalid conversion.');
        return false;
      }

      const decimal = parseInt(input, srcBase);
      const result = decimal.toString(dstBase);

      msg.resolve('Result:', result);
      return true;
    },
    description: 'Convert a value into a value in another numbering system.',
    usage: '<value> <bin/dec/hex/oct> <bin/dec/hex/oct>',
    aliases: ['convertnumbers', 'cvnums']
  });

  cmds.push({
    name: 'convertseconds',
    execute: async (msg: IMessage, spec: any, prefix: string, ...simplified: any[]): Promise<boolean> => {
      msg.resolve(readableTime(parseInt(simplified[0], 10)));
      return true;
    },
    description: 'Convert seconds to years days hours minutes seconds.',
    usage: '<seconds>',
    aliases: ['cvs', 'parseseconds']
  });

  cmds.push({
    name: 'converttime',
    execute: async (msg: IMessage, spec: any, prefix: string, ...simplified: any[]): Promise<boolean> => {
      const str = msg.data.split(' ').slice(1).join(' ');

      if (!str) {
        msg.resolve('Invalid input');
        return true;
      }

      msg.resolve(parseTimeToSeconds(str) + ' seconds');
      return true;
    },
    description: 'Convert ywdhms to seconds.',
    usage: '[<years>y] [<weeks>w] [<days>d] [<hours>h] [<minutes>m] [<seconds>s]',
    aliases: ['cvt', 'parsetime']
  });

  cmds.push({
    name: 'reconverttime',
    execute: async (msg: IMessage, spec: any, prefix: string, ...simplified: any[]): Promise<boolean> => {
      const str = msg.data.split(' ').slice(1).join(' ');

      if (!str) {
        msg.resolve('Invalid input');
        return true;
      }

      const sec = parseTimeToSeconds(str);
      msg.resolve(readableTime(sec));

      return true;
    },
    aliases: ['rcvt']
  });

  cmds.push({
    name: 'eval',
    execute: async (msg: IMessage, spec: any, prefix: string, ...simplified: any[]): Promise<boolean> => {
      if (!simplified[0]) {
        return true;
      }

      const wholeRow = msg.data.split(' ').slice(1).join(' ');

      opMath(wholeRow).then((repl) => {
        msg.resolve(repl);
      }, (e) => {
        msg.resolve('Could not evaluate expression:', e.message);
      });

      return true;
    },
    aliases: ['evaluate', 'math', 'equation', 'calc'],
    usage: '<expression>',
    description: 'Evaluate a math expression'
  });

  cmds.push({
    name: 'simplify',
    execute: async (msg: IMessage, spec: any, prefix: string, ...simplified: any[]): Promise<boolean> => {
      if (!simplified[0]) {
        return true;
      }

      const wholeRow = msg.data.split(' ').slice(1).join(' ');

      opMath(wholeRow, 'simplify').then((repl) => {
        msg.resolve(repl);
      }, () => {
        msg.resolve('Could not evaluate expression!');
      });

      return true;
    },
    aliases: ['mathsimple', 'algebra'],
    usage: '<expression>',
    description: 'Simplify a math expression'
  });

  cmds.push({
    name: 'evaljs',
    execute: async (msg: IMessage, spec: any, prefix: string, ...simplified: any[]): Promise<boolean> => {
      if (!simplified[0]) {
        return true;
      }
      const script = msg.data.split(' ').slice(1).join(' ');

      // Disallow child_process when shell is disallowed
      if ((script.indexOf('child_process') !== -1 ||
          script.indexOf('cprog') !== -1 ||
          script.indexOf('fork') !== -1) &&
          !plugin.config.config.allowShell) {
        msg.resolve('Error: child_process is not allowed in evaljs due to security reasons.');
        return true;
      }

      try {
        const mesh = eval(script); /* eslint no-eval: off */
        if (mesh === undefined) {
          return true;
        }
        msg.resolve(util.format(mesh));
      } catch (e) {
        msg.resolve('Error: ' + e.message);
      }

      return true;
    },
    description: 'Execute JavaScript in a command context',
    permissions: ['system_execute'],
    hidden: true
  });

  cmds.push({
    name: 'userid',
    execute: async (msg: IMessage, spec: any, prefix: string, ...simplified: any[]): Promise<boolean> => {
      msg.resolve('Your userId is %s.', msg.fullSenderID);
      return true;
    },
    description: 'Display your userId (internal user identification)',
    hidden: true
  });

  cmds.push({
    name: 'roomid',
    execute: async (msg: IMessage, spec: any, prefix: string, ...simplified: any[]): Promise<boolean> => {
      msg.resolve('Current roomId is %s.', msg.fullRoomID);
      return true;
    },
    description: 'Display the internal identification of this room',
    hidden: true
  });

  cmds.push({
    name: 'serverid',
    execute: async (msg: IMessage, spec: any, prefix: string, ...simplified: any[]): Promise<boolean> => {
      if (msg.target && msg.target.server) {
        msg.resolve('Current server ID is s:%s.', msg.target.server);
        return true;
      }

      msg.resolve('This protocol does not specify a server. ' +
        'Either the protocol is for a single server only or the server variable is not supported.');

      return true;
    },
    description: 'Display the internal identification of this room',
    hidden: true
  });

  cmds.push({
    name: 'rgb2hex',
    execute: async (msg: IMessage, spec: any, prefix: string, ...simplified: any[]): Promise<boolean> => {
      if (!simplified[0]) {
        return true;
      }

      const fullmsg = msg.data.split(' ').slice(1).join(' ');
      const channels = fullmsg.match(/(rgb)?\(?(\d{1,3}),?\s(\d{1,3}),?\s(\d{1,3})\)?/i);
      if (!channels || channels[2] == null) {
        msg.resolve('Invalid parameter');
        return true;
      }

      const r = parseInt(channels[2], 10);
      const g = parseInt(channels[3], 10);
      const b = parseInt(channels[4], 10);

      if (r > 255 || g > 255 || b > 255) {
        msg.resolve('Invalid colors');
        return true;
      }
      const hex = rgbToHex(r, g, b);

      msg.resolve(hex);
      return true;
    },
    description: 'Convert RGB to HEX colors',
    usage: '[rgb](<r>, <g>, <b>)|<r> <g> <b>'
  });

  cmds.push({
    name: 'hex2rgb',
    execute: async (msg: IMessage, spec: any, prefix: string, ...simplified: any[]): Promise<boolean> => {
      if (!simplified[0]) {
        return true;
      }
      let hexcode = simplified[0];

      if (hexcode.indexOf('#') === -1) {
        hexcode = '#' + hexcode;
      }

      if (hexcode.length !== 4 && hexcode.length !== 7) {
        msg.resolve('Invalid length');
        return true;
      }

      const rgb = hexToRgb(hexcode);
      if (!rgb) {
        msg.resolve('Invalid HEX notation');
        return true;
      }

      msg.resolve('rgb(%d, %d, %d)', rgb.r, rgb.g, rgb.b);
      return true;
    },
    description: 'Convert HEX to RGB colors',
    usage: '#<r><g><b>|#<rr><gg><bb>'
  });

  cmds.push({
    name: 'isup',
    execute: async (msg: IMessage, spec: any, prefix: string, ...simplified: any[]): Promise<boolean> => {
      if (!simplified[0]) {
        msg.resolve('Please specify host name!');
        return true;
      }
      if (!simplified[1]) {
        msg.resolve('Please specify port!');
        return true;
      }

      const host = simplified[0];
      const port = parseInt(simplified[1], 10);

      if (isNaN(port) || port <= 0 || port > 65535) {
        msg.resolve('Invalid port number!');
        return true;
      }

      let statusString = msg.source.format.format('bold', 'closed');
      let status;

      try {
        status = await pingTcpServer(host, port);
        statusString = msg.source.format.format('bold', 'open');
      } catch (e) {
        status = e.message;
      }

      if (!isNaN(parseFloat(status))) {
        status = status + ' ms';
      }

      msg.resolve(`Port ${port} on ${host} is ${statusString} (${status})`);
      return true;
    },
    description: 'Ping a host',
    usage: '<host> <port>',
    aliases: ['tcpup', 'tping'],
    hidden: true
  });

  cmds.push({
    name: 'convert',
    execute: async (msg: IMessage, spec: any, prefix: string, ...simplified: any[]): Promise<boolean> => {
      const tqnt = parseFloat(simplified[0]);
      if (isNaN(tqnt)) {
        msg.resolve('Please specify a quantity, either an integer or a float!');
        return true;
      }

      const src = simplified[1];
      let dst = simplified[2];
      if (dst && dst.toLowerCase() === 'to') {
        dst = simplified[3];
      }

      if (!src) {
        msg.resolve('Please specify source unit!');
        return true;
      }

      if (!dst) {
        msg.resolve('Please specify destination unit!');
        return true;
      }

      let res = null;

      try {
        res = convert(tqnt).from(src).to(dst);
      } catch (e) {
        res = null;
      }

      if (res) {
        const srcdesc = convert().describe(src);
        const dstdesc = convert().describe(dst);

        const bsrcdesc = (Math.floor(tqnt) !== 1) ? srcdesc.plural : srcdesc.singular;
        const bdstdesc = (Math.floor(res) !== 1) ? dstdesc.plural : dstdesc.singular;

        msg.resolve(` ${tqnt} ${bsrcdesc} => ${res} ${bdstdesc}`);
        return true;
      }

      msg.resolve('Failed to convert.');
      return true;
    },
    description: 'Convert between quantities in different units.',
    usage: '<number> <from unit> <to unit>',
    aliases: ['cv', 'unit']
  });

  cmds.push({
    name: 'currency',
    execute: async (msg: IMessage, spec: any, prefix: string, ...simplified: any[]): Promise<boolean> => {
      let ctw: CEXResponse | null = cexCache.cache as CEXResponse;
      if (cexCache.expiry < Date.now()) {
        let fetched;
        try {
          const data = await httpGET('https://api.exchangeratesapi.io/latest');
          fetched = JSON.parse(data);
          logger.log('[utility] Fetched currency exchange rates successfully.');
        } catch (e) {
          ctw = null;
        }

        if (!ctw || !fetched.rates) {
          msg.resolve('Could not fetch currency exchange rates at this time. Please try again later.');
          return true;
        }

        cexCache.cache = fetched.rates;
        cexCache.date = fetched.date;
        cexCache.expiry = Date.now() + 86400000; // day
        ctw = cexCache.cache as CEXResponse;
      }

      if (simplified[0] === 'date') {
        msg.resolve('Currency exchange rates are as of %s', cexCache.date);
        return true;
      } else if (simplified[0] === 'list') {
        msg.resolve('Currently supported currencies: EUR, %s', Object.keys(cexCache.cache).join(', '));
        return true;
      }

      const n = parseFloat(simplified[0]);
      let f = simplified[1];
      let t = simplified[2];
      if (isNaN(n) || !f || !t) {
        msg.resolve('Invalid parameters.');
        return true;
      }
      f = f.toUpperCase();
      t = t.toUpperCase();

      if (f !== 'EUR' && !ctw[f]) {
        msg.resolve('This currency is currently not supported.');
        return true;
      }

      if (t !== 'EUR' && !ctw[t]) {
        msg.resolve('This currency is currently not supported.');
        return true;
      }

      if (f === t) {
        msg.resolve('%f %s', n, f);
        return true;
      }

      let ramnt: string;
      if (f === 'EUR') {
        ramnt = (n * ctw[t]).toFixed(4);
        msg.resolve('%f EUR => %f %s', n, ramnt, t);
        return true;
      } else if (t === 'EUR') {
        ramnt = (n / ctw[f]).toFixed(4);
        msg.resolve('%f %s => %f EUR', n, f, ramnt);
        return true;
      }

      const amnt = (ctw[t] * n / ctw[f]).toFixed(4);
      msg.resolve('%f %s => %f %s', n, f, amnt, t);
      return true;
    },
    description: 'Convert between currencies.',
    usage: '<number> | [date | list] [<from currency>] [<to currency>]',
    aliases: ['cex', 'exchange']
  });

  cmds.push({
    name: 'randomnumber',
    execute: async (msg: IMessage, spec: any, prefix: string, ...simplified: any[]): Promise<boolean> => {
      let min = parseInt(simplified[0], 10);
      let max = parseInt(simplified[1], 10);
      let count = parseInt(simplified[2], 10);
      const countMax = plugin.config.config.randomMax || 64;
      if (isNaN(min) || isNaN(max)) {
        msg.resolve('Invalid numbers.');
        return true;
      }
      if (min > max) {
        const realMax = min + 0;
        min = max;
        max = realMax;
      }
      if (isNaN(count)) { count = 1; }
      if (String(Math.abs(min)).length > 9 || String(Math.abs(max)).length > 9) {
        msg.resolve('The numbers are too large!');
        return true;
      }
      if (count > countMax) {
        msg.resolve('Too many to generate. Maximum: ' + countMax);
        return true;
      }
      const numbers = [];
      for (let i = 0; i < count; i++) {
        numbers.push(Math.floor(Math.random() * (max - min + 1)) + min);
      }
      msg.resolve(numbers.join(' '));
      return true;
    },
    description: 'Generate a random number between <min> and <max>.',
    usage: '<min> <max> [<count>]',
    aliases: ['rnum', 'rand']
  });

  if (plugin.config.config.allowShell) {
    logger.warn('WARNING! Shell command execution is enabled! Make absolutely sure that there is proper authentication!');
    if (process.getuid && process.getuid() === 0) {
      logger.warn('NEVER run Squeebot as root! Run `useradd squeebot`! We are not responsible for possible security leaks!');
    }

    cmds.push({
      name: 'sh',
      execute: async (msg: IMessage, spec: any, prefix: string, ...simplified: any[]): Promise<boolean> => {
        const stripnl = (simplified[0] !== '-n');
        const cmd = simplified.slice(stripnl ? 0 : 1).join(' ');
        if (!cmd) {
          msg.resolve('Nothing to execute!');
          return true;
        }

        cprog.exec(cmd, {shell: '/bin/bash'}, (error, stdout, stderr) => {
          if (stdout) {
            if (stripnl) { stdout = stdout.replace(/\n/g, ' ;; '); }

            return msg.resolve(stdout);
          }

          msg.resolve('Error executing command.');
          logger.error(stderr || error);
        });

        return true;
      },
      description: 'Run raw shell command.',
      usage: '<query>',
      hidden: true,
      permissions: ['system_execute'],
    });
  }

  commands.registerCommand(cmds.map((x: any) => {
    x.plugin = plugin.manifest.name;
    return x;
  }));
}

@Configurable({
  allowShell: false,
  googleapikey: null,
  ipfsGateway: 'https://ipfs.io',
  randomMax: 64
})
class UtilityPlugin extends Plugin {
  bindEvents(): void {
    this.on('message', (msg: IMessage) => {
      // Pre-regex check
      if (msg.data.indexOf('ipfs://') === -1 && msg.data.indexOf('Qm') === -1) {
        return;
      }

      // IPFS urlify
      const mmatch = msg.data.match(/(?:ipfs:\/\/|\s|^)(Qm[\w\d]{44})(?:\s|$)/);
      if (mmatch && mmatch[1]) {
        msg.resolve(this.config.config.ipfsGateway + '/ipfs/' + mmatch[1]);
      }
    });
  }

  @DependencyLoad('simplecommands')
  addCommands(cmd: any): void {
    addCommands(this, cmd);
  }

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

  initialize(): void {
    this.bindEvents();
    this.emit('pluginLoaded', this);
  }
}

module.exports = UtilityPlugin;