import * as BinaryPack from "js-binarypack";
import { RTCPeerConnection } from "./adapter";

const DEFAULT_CONFIG = {
  iceServers: [{ urls: "stun:stun.l.google.com:19302" }]
};

/*
Prints log messages depending on the debug level passed in. Defaults to 0.
0  Prints no logs.
1  Prints only errors.
2  Prints errors and warnings.
3  Prints all logs.
*/
const enum DebugLevel {
  Disabled,
  Errors,
  Warnings,
  All
}

export class util {
  static noop(): void {}

  static readonly CLOUD_HOST = "0.peerjs.com";
  static readonly CLOUD_PORT = 443;

  // Browsers that need chunking:
  static readonly chunkedBrowsers = { Chrome: 1 };
  static readonly chunkedMTU = 16300; // The original 60000 bytes setting does not work when sending data from Firefox to Chrome, which is "cut off" after 16384 bytes and delivered individually.

  // Logging logic
  static readonly debug = false;
  static logLevel = DebugLevel.Disabled;

  static setLogLevel(level: string): void {
    const debugLevel = parseInt(level, 10);

    if (!isNaN(parseInt(level, 10))) {
      util.logLevel = debugLevel;
    } else {
      // If they are using truthy/falsy values for debug
      util.logLevel = level ? DebugLevel.All : DebugLevel.Disabled;
    }
    util.log = util.warn = util.error = util.noop;
    if (util.logLevel > DebugLevel.Disabled) {
      util.error = util._printWith("ERROR");
    }
    if (util.logLevel > DebugLevel.Errors) {
      util.warn = util._printWith("WARNING");
    }
    if (util.logLevel > DebugLevel.Warnings) {
      util.log = util._print;
    }
  }

  static setLogFunction(fn): void {
    if (fn.constructor !== Function) {
      util.warn(
        "The log function you passed in is not a function. Defaulting to regular logs."
      );
    } else {
      util._print = fn;
    }
  }

  private static _printWith(prefix) {
    return function() {
      const copy = Array.prototype.slice.call(arguments);
      copy.unshift(prefix);
      util._print.apply(util, copy);
    };
  }

  private static _print(...rest): void {
    let err = false;
    const copy = [...rest];

    copy.unshift("PeerJS: ");

    for (let i in copy) {
      if (copy[i] instanceof Error) {
        copy[i] = "(" + copy[i].name + ") " + copy[i].message;
        err = true;
      }
    }

    err ? console.error.apply(console, copy) : console.log.apply(console, copy);
  }

  // Returns browser-agnostic default config
  static readonly defaultConfig = DEFAULT_CONFIG;

  // Returns the current browser.
  static readonly browser: string = (function(global) {
    // @ts-ignore
    if (global.mozRTCPeerConnection) {
      return "Firefox";
    }
    // @ts-ignore
    if (global.webkitRTCPeerConnection) {
      return "Chrome";
    }

    if (global.RTCPeerConnection) {
      return "Supported";
    }

    return "Unsupported";
  })(window);

  // Lists which features are supported
  static readonly supports = (function() {
    if (typeof RTCPeerConnection === "undefined") {
      return {};
    }

    let data = true;
    let audioVideo = true;

    let binaryBlob = false;
    let sctp = false;
    // @ts-ignore
    const onnegotiationneeded = !!window.webkitRTCPeerConnection;

    let pc, dc;

    try {
      pc = new RTCPeerConnection(DEFAULT_CONFIG, {
        optional: [{ RtpDataChannels: true }]
      });
    } catch (e) {
      data = false;
      audioVideo = false;
    }

    if (data) {
      try {
        dc = pc.createDataChannel("_PEERJSTEST");
      } catch (e) {
        data = false;
      }
    }

    if (data) {
      // Binary test
      try {
        dc.binaryType = "blob";
        binaryBlob = true;
      } catch (e) {}

      // Reliable test.
      // Unfortunately Chrome is a bit unreliable about whether or not they
      // support reliable.
      const reliablePC = new RTCPeerConnection(DEFAULT_CONFIG, {});
      try {
        const reliableDC = reliablePC.createDataChannel(
          "_PEERJSRELIABLETEST",
          {}
        );
        sctp = reliableDC.reliable;
      } catch (e) {}
      reliablePC.close();
    }

    // FIXME: not really the best check...
    if (audioVideo) {
      audioVideo = !!pc.addStream;
    }

    // FIXME: this is not great because in theory it doesn't work for
    // av-only browsers (?).
    /*
    if (!onnegotiationneeded && data) {
      // sync default check.
      var negotiationPC = new RTCPeerConnection(defaultConfig, {optional: [{RtpDataChannels: true}]});
      negotiationPC.onnegotiationneeded = function() {
        onnegotiationneeded = true;
        // async check.
        if (util && util.supports) {
          util.supports.onnegotiationneeded = true;
        }
      };
      negotiationPC.createDataChannel('_PEERJSNEGOTIATIONTEST');

      setTimeout(function() {
        negotiationPC.close();
      }, 1000);
    }
    */

    if (pc) {
      pc.close();
    }

    return {
      audioVideo: audioVideo,
      data: data,
      binaryBlob: binaryBlob,
      binary: sctp, // deprecated; sctp implies binary support.
      reliable: sctp, // deprecated; sctp implies reliable data.
      sctp: sctp,
      onnegotiationneeded: onnegotiationneeded
    };
  })();

  // Ensure alphanumeric ids
  static validateId(id: string): boolean {
    // Allow empty ids
    return !id || /^[A-Za-z0-9]+(?:[ _-][A-Za-z0-9]+)*$/.test(id);
  }

  static inherits(ctor, superCtor): void {
    ctor.super_ = superCtor;
    ctor.prototype = Object.create(superCtor.prototype, {
      constructor: {
        value: ctor,
        enumerable: false,
        writable: true,
        configurable: true
      }
    });
  }

  static extend(dest, source): any {
    for (let key in source) {
      if (source.hasOwnProperty(key)) {
        dest[key] = source[key];
      }
    }
    return dest;
  }

  static pack = BinaryPack.pack;
  static unpack = BinaryPack.unpack;

  static log(...rest): void {
    if (!util.debug) return;

    let err = false;
    const copy = [...rest];

    copy.unshift("PeerJS: ");

    for (let i in copy) {
      if (copy[i] instanceof Error) {
        copy[i] = "(" + copy[i].name + ") " + copy[i].message;
        err = true;
      }
    }

    err ? console.error.apply(console, copy) : console.log.apply(console, copy);
  }

  static warn(...rest): void {}
  static error(...rest): void {}

  static setZeroTimeout = (global => {
    const timeouts = [];
    const messageName = "zero-timeout-message";

    // Like setTimeout, but only takes a function argument.	 There's
    // no time argument (always zero) and no arguments (you have to
    // use a closure).
    function setZeroTimeoutPostMessage(fn) {
      timeouts.push(fn);
      global.postMessage(messageName, "*");
    }

    function handleMessage(event) {
      if (event.source === global && event.data === messageName) {
        if (event.stopPropagation) {
          event.stopPropagation();
        }
        if (timeouts.length) {
          timeouts.shift()();
        }
      }
    }

    if (global.addEventListener) {
      global.addEventListener("message", handleMessage, true);
    }
    // @ts-ignore
    else if (global.attachEvent) {
      // @ts-ignore
      global.attachEvent("onmessage", handleMessage);
    }

    return setZeroTimeoutPostMessage;
  })(window);

  // Binary stuff

  private static _dataCount = 1;

  // chunks a blob.
  static chunk(bl: Blob): any[] {
    const chunks = [];
    const size = bl.size;
    const total = Math.ceil(size / util.chunkedMTU);

    let index;
    let start = (index = 0);

    while (start < size) {
      const end = Math.min(size, start + util.chunkedMTU);
      const b = bl.slice(start, end);

      const chunk = {
        __peerData: this._dataCount,
        n: index,
        data: b,
        total: total
      };

      chunks.push(chunk);

      start = end;
      index++;
    }

    this._dataCount++;

    return chunks;
  }

  static blobToArrayBuffer(blob: Blob, cb: (arg: any) => void): void {
    const fr = new FileReader();

    fr.onload = function(evt) {
      // @ts-ignore
      cb(evt.target.result);
    };

    fr.readAsArrayBuffer(blob);
  }

  static blobToBinaryString(blob: Blob, cb: (arg: any) => void): void {
    const fr = new FileReader();

    fr.onload = function(evt) {
      // @ts-ignore
      cb(evt.target.result);
    };

    fr.readAsBinaryString(blob);
  }

  static binaryStringToArrayBuffer(binary): ArrayBuffer | SharedArrayBuffer {
    let byteArray = new Uint8Array(binary.length);

    for (let i = 0; i < binary.length; i++) {
      byteArray[i] = binary.charCodeAt(i) & 0xff;
    }

    return byteArray.buffer;
  }

  static randomToken(): string {
    return Math.random()
      .toString(36)
      .substr(2);
  }

  static isSecure(): boolean {
    return location.protocol === "https:";
  }
}