/* socket.js, a simple wrapper for a YWOT websocket connection */
const ws = require('ws')
const EventEmitter = require('events');

class retryws extends EventEmitter{ // a wrapper on ws that retries on failure
  constructor(addr) {
    let sock;
    this.sockdown = true; 
    this.send = (message) => {
      if (sockdown){
        throw "Socket is down!";
      }
      sock.send(message);
    }
    function sockinit(){ // addr is not expected to change, so not handed as input; similarly, sock is not passed in a chain because behavior is expected to be serial (either initializing or retrying)
      sock = new ws(addr);
      sock.on('open', () => { this.emit('open'); sockdown = false; });
      sock.on('close', (err) => { setTimeout(sockinit,1000); sockdown = true; this.emit('close'); });
      sock.on('error', (err) => { sock.close(); });
      sock.on('message', (message) => { this.emit('message',message); });
    }
  }
}


class Socket extends retryws {
  constructor(world='') { // Takes the name of the world, which can be an empty string.
    let loc = (name = '') ? '' : `/${name}`;
    let addr = `wss://www.yourworldoftext.com/${loc}ws`;
    super(addr);
    this.on('message', (msg)=>{
      msg = JSON.parse(msg);
      switch (message.kind){
        case 'write':
          this.emit('write', message.accepted, message.rejected); break; // A confirmation message for writes (accepted/rejected updates)
        case 'cursor':
          this.emit('cursor', message.positions, message.sender); break; // Must be used for self-identification
        case 'tileUpdate':
          this.emit('tileUpdate', message.sender, message.source, message.tiles); break; // Any change by another user or possibly oneself
        case 'fetch':
          this.emit('fetch', message.tiles); break; // The response to a fetch request
      }
    });

    this.fetch = function(coords){ //coords is a list of quadruplets, each a min/max pair of y/x coordinate pairs which describes at most 1000 tiles
    //Unchecked for speed
      for (var i=0; i<coords.length; i++){
        coords[i] = {"minY":coords[i][0], "minX":coords[i][1], "maxY":coords[i][2], "maxX":coords[i][3]};
      }
      this.send(`{"fetchRectangles":${JSON.stringify(coords)},"kind":"fetch","v":"3"}`);
    }

    this.write = function(chars){ //chars is an list of triplets [ tile coordinate (y/x), pixel coordinate (y/x < 16), char ]
      if (chars.length > 200){
        throw "Too many characters to write";
      }
      for (var i=0; i<chars.length; i++){
        chars[i].splice(4,0,0); //
        chars[i].push(i);
      }
      this.send(`{"edits":${JSON.stringify(chars)},"kind":"write"}`);
    }
    
    this.cursor = function(coords){ //coords is just one quadruplet analagous to fetch; I think the api could handle more, but it's unnecessary for now.
      this.send(`"kind":"cursor","positions":[${JSON.stringify(coords)}]}`);
    }

  }
}

exports.Socket = Socket;