/* rlgterm.js: Roguelike Gallery's driver for termemu.js */

// A state machine that keeps track of polling the server.
var ajaxstate = {
  state: 0,
  timerID: null,
  clear: function () {
    if (this.timerID != null) {
      window.clearTimeout(this.timerID);
      this.timerID = null;
    }
  },
  set: function (ms) {
    this.clear();
    this.timerID = window.setTimeout(getData, ms);
  },
  gotdata: function () {
    this.set(100);
    this.state = 0;
  },
  gotnothing: function () {
    if (this.state == 0) {
      this.set(100);
      this.state = 1;
    }
    else if (this.state == 1) {
      this.set(300);
      this.state = 2;
    }
    else if (this.state == 2) {
      this.set(1000);
      this.state = 3;
    }
    else {
      this.set(5000);
      this.state = 3;
    }
  },
  posted: function () {
    this.set(100);
    this.state = 0;
  }
};

function writeData(hexstr) {
  var codenum;
  var codes = [];
  var nc;
  var u8wait = 0; /* Stores bits from previous bytes of multibyte sequences. */
  var expect = 0; /* The number of 10------ bytes expected. */
  /* UTF-8 translation. */
  for (var i = 0; i < hexstr.length; i += 2) {
    nc = Number("0x" + hexstr.substr(i, 2));
    if (nc < 0x7F) {
      /* 0------- */
      codes.push(nc);
      /* Any incomplete sequence will be discarded. */
      u8wait = 0;
      expect = 0;
    }
    else if (nc < 0xC0) {
      /* 10------ : part of a multibyte sequence */
      if (expect > 0) {
        u8wait <<= 6;
        u8wait += (nc & 0x3F);
        expect--;
        if (expect == 0) {
          codes.push(u8wait);
          u8wait = 0;
        }
      }
      else {
        /* Assume an initial byte was missed. */
        u8wait = 0;
      }
    }
    /* These will all discard any incomplete sequence. */
    else if (nc < 0xE0) {
      /* 110----- : introduces 2-byte sequence */
      u8wait = (nc & 0x1F);
      expect = 1;
    }
    else if (nc < 0xF0) {
      /* 1110---- : introduces 3-byte sequence */
      u8wait = (nc & 0x0F);
      expect = 2;
    }
    else if (nc < 0xF8) {
      /* 11110--- : introduces 4-byte sequence */
      u8wait = (nc & 0x07);
      expect = 3;
    }
    else if (nc < 0xFC) {
      /* 111110-- : introduces 5-byte sequence */
      u8wait = (nc & 0x03);
      expect = 4;
    }
    else if (nc < 0xFE) {
      /* 1111110- : introduces 6-byte sequence */
      u8wait = (nc & 0x01);
      expect = 5;
    }
    else {
      /* 1111111- : should never appear */
      u8wait = 0;
      expect = 0;
    }
    /* Supporting all 31 bits is probably overkill... */
  }
  termemu.write(codes);
  return;
}

/* State for sending and receiving messages. */
var nsend = 0; // The number of the next packet to send.
var nrecv = 0; // The next packet expected.
var msgQ = []; // Queue for out-of-order messages.

/* Processes a message from the server, returning true or false if it was a 
 * data message with or without data, null if not data.
 * All non-special responseTexts should be handed directly to this function.
 */
function processMsg(msg) {
  var msgDict;
  var havedata = null; // eventual return value
  try {
    msgDict = JSON.parse(msg);
  } catch (e) {
    if (e instanceof SyntaxError)
      return null;
  }
  if (!msgDict.t)
    return null;
  else if (msgDict.t == "E") {
    if (msgDict.c == 1) {
      logout();
    }
    debug(1, "Server error: " + msgDict.s);
  }
  else if (msgDict.t == "n") {
    havedata = false;
  }
  // A data message
  else if (msgDict.t == "d"){
    if (msgDict.n === nrecv) {
      writeData(msgDict.d);
      nrecv++;
      /* Process anything in the queue that's now ready. */
      var next;
      while ((next = msgQ.shift()) !== undefined) {
        writeData(next.d);
        nrecv++;
      }
    }
    else if (response.n > nrecv) {
      /* The current message comes after one still missing.  Queue this one
       * for later use. */
      debug(1, "Got packet " + msgDict.n + ", expected " + nrecv);
      msgQ[msgDict.n - nrecv - 1] = msgDict;
    }
    else {
      /* This message's number was encountered previously. */
      debug(1, "Discarding packet " + msgDict.n + ", expected " + nrecv);
    }
    havedata = true;
  }
  else if (msgDict.t == "T") {
    setTitle(msgDict.d);
  }
  else if (msgDict.t == "q") {
    logout();
  }
  else {
    debug(1, "Unrecognized server message " + msg);
  }
  return havedata;
}

function getData() {
  if (termemu.sessid == null)
    return;
  var datareq = new XMLHttpRequest();
  var msg = JSON.stringify({"id": termemu.sessid, "t": "n"});
  datareq.onreadystatechange = function () {
    if (datareq.readyState == 4 && datareq.status == 200) {
      var wasdata = processMsg(datareq.responseText);
      if (wasdata != null) {
        if (wasdata)
          ajaxstate.gotdata();
        else
          ajaxstate.gotnothing();
      }
      return;
    }
  };
  datareq.open('POST', '/feed', true);
  datareq.send(msg);
  return;
}

function postResponseHandler() {
  if (this.readyState == 4 && this.status == 200) {
    // We might want to do something with wasdata someday.
    var wasdata = processMsg(this.responseText);
    ajaxstate.posted();
    return;
  }
}

function sendback(str) {
  /* For responding to terminal queries. */
  var msgDict = {"id": termemu.sessid, "t": "d", "n": nsend++, "d": str};
  var datareq = new XMLHttpRequest();
  datareq.onreadystatechange = postResponseHandler;
  datareq.open('POST', '/feed', true);
  datareq.send(JSON.stringify(msgDict));
  return;
}

function sendkey(ev) {
  if (termemu.sessid == null)
    return;
  var keynum = ev.keyCode;
  var code;
  if (keynum >= ev.DOM_VK_A && keynum <= ev.DOM_VK_Z) {
    /* Letters.  This assumes the codes are 65-90. */
    if (ev.ctrlKey)
      keynum -= 64;
    else if (!ev.shiftKey)
      keynum += 32;
    code = keynum.toString(16);
    if (code.length < 2)
      code = "0" + code;
  }
  else if (keynum >= ev.DOM_VK_0 && keynum <= ev.DOM_VK_9) {
    /* The number row, NOT the numpad. */
    if (ev.shiftKey) {
      code = numShifts[keynum - 48].toString(16);
    }
    else {
      code = keynum.toString(16);
    }
  }
  else if (keynum in keyHexCodes) {
    if (ev.shiftKey)
      code = keyHexCodes[keynum][1];
    else
      code = keyHexCodes[keynum][0];
  }
  else if (keynum == ev.DOM_VK_SHIFT || keynum == ev.DOM_VK_CONTROL ||
           keynum == ev.DOM_VK_ALT || keynum == ev.DOM_VK_CAPS_LOCK) {
    return;
  }
  else {
    debug(1, "Ignoring keycode " + keynum);
    return;
  }
  // Isn't this check redundant?
  if (termemu.sessid != null)
    ev.preventDefault();
  var datareq = new XMLHttpRequest();
  var msgDict = {"id": termemu.sessid, "t": "d", "n": nsend++, "d": code};
  datareq.onreadystatechange = postResponseHandler;
  datareq.open('POST', '/feed', true);
  datareq.send(JSON.stringify(msgDict));
  return;
}

var charshifts = { '-': "5f", '=': "2b", '[': "7b", ']': "7d", '\\': "7c",
  ';': "3a", '\'': "22", ',': "3c", '.': "3e", '/': "3f", '`': "7e"
}

function vkey(c) {
  if (termemu.sessid == null)
    return;
  var keystr;
  if (c.match(/^[a-z]$/)) {
    if (termemu.ctrlp()) {
      var n = c.charCodeAt(0) - 96;
      keystr = n.toString(16);
      if (keystr.length < 2)
        keystr = "0" + keystr;
    }
    else if (termemu.shiftp())
      keystr = c.toUpperCase().charCodeAt(0).toString(16);
    else
      keystr = c.charCodeAt(0).toString(16);
  }
  else if (c.match(/^[0-9]$/)) {
    if (termemu.shiftp())
      keystr = numShifts[c.charCodeAt(0) - 48].toString(16);
    else
      keystr = c.charCodeAt(0).toString(16);
  }
  else if (c == '\n')
    keystr = "0a";
  else if (c == '\t')
    keystr = "09";
  else if (c == '\b')
    keystr = "08";
  else if (c == ' ')
    keystr = "20";
  else if (c in charshifts) {
    if (termemu.shiftp())
      keystr = charshifts[c];
    else
      keystr = c.charCodeAt(0).toString(16);
  }
  else
    return;
  var datareq = new XMLHttpRequest();
  var msgDict = {"id": termemu.sessid, "t": "d", "n": nsend++, "d": keystr};
  datareq.onreadystatechange = postResponseHandler;
  datareq.open('POST', '/feed', true);
  datareq.send(JSON.stringify(msgDict));
  return;
}

function setup() {
  keyHexCodes.init();
  termemu.init("termwrap", 24, 80);
  setTitle("Not connected.");
  return;
}

function toggleshift() {
  termemu.toggleshift();
  keydiv = document.getElementById("shiftkey");
  if (termemu.shiftp())
    keydiv.className = "keysel";
  else
    keydiv.className = "key";
  return;
}

function togglectrl() {
  termemu.togglectrl();
  keydiv = document.getElementById("ctrlkey");
  if (termemu.ctrlp())
    keydiv.className = "keysel";
  else
    keydiv.className = "key";
  return;
}

function formlogin(ev) {
  ev.preventDefault();
  if (termemu.sessid != null)
    return;
  var loginmsg = {};
  loginmsg["name"] = document.getElementById("input_name").value;
  loginmsg["pw"] = document.getElementById("input_pw").value;
  loginmsg["game"] = document.getElementById("input_game").value;
  loginmsg["h"] = 24;
  loginmsg["w"] = 80;
  var req = new XMLHttpRequest();
  req.onreadystatechange = function () {
    if (req.readyState != 4 || req.status != 200) 
      return;
    var reply = JSON.parse(req.responseText);
    if (reply.t == 'l') {
      /* Success */
      termemu.sessid = reply.id;
      termemu.resize(reply.h, reply.w);
      setTitle("Playing as " + loginmsg["name"]);
      debug(1, "Logged in with id " + termemu.sessid);
      document.getElementById("loginform").style.display = "none";
      getData();
    }
    else if (reply.t == 'E') {
      debug(1, "Could not start game: " + reply.s);
      document.getElementById("input_name").value = "";
      document.getElementById("input_pw").value = "";
    }
  };
  req.open('POST', '/login', true);
  req.send(JSON.stringify(loginmsg));
  return;
}

function logout() {
  if (termemu.sessid == null)
    return;
  termemu.sessid = null;
  setTitle("Game over.");
  nsend = 0;
  nrecv = 0;
  msgQ = [];
  document.getElementById("loginform").style.display = "block";
  return;
}

function stop() {
  var req = new XMLHttpRequest();
  req.onreadystatechange = function () {
    if (req.readyState == 4 && req.status == 200) {
      processMsg(req.responseText);
      return;
    }
  };
  req.open('POST', '/feed', true);
  req.send(JSON.stringify({"id": termemu.sessid, "t": "q"}));
  return;
}

function debug(level, msg) {
  if (level < debugSuppress)
    return;
  var msgdiv = document.createElement("div");
  var msgtext = document.createTextNode(msg);
  msgdiv.appendChild(msgtext);
  document.getElementById("debug").appendChild(msgdiv);
  return;
}

function textsize(larger) {
  var cssSize = termemu.view.style.fontSize;
  if (!cssSize) {
    return;
  }
  var match = cssSize.match(/\d*/);
  if (!match) {
    return;
  }
  var csize = Number(match[0]);
  var nsize;
  if (larger) {
    if (csize >= 48)
      nsize = 48;
    else if (csize >= 20)
      nsize = csize + 4;
    else if (csize >= 12)
      nsize = csize + 2;
    else if (csize >= 8)
      nsize = csize + 1;
    else
      nsize = 8;
  }
  else {
    if (csize <= 8)
      nsize = 8;
    else if (csize <= 12)
      nsize = csize - 1;
    else if (csize <= 20)
      nsize = csize - 2;
    else if (csize <= 48)
      nsize = csize - 4;
    else
      nsize = 48;
  }
  document.getElementById("term").style.fontSize = nsize.toString() + "px";
  termemu.fixsize();
  debug(1, "Changing font size to " + nsize.toString());
  return;
}

function bell(on) {
  var imgnode = document.getElementById("bell");
  if (on) {
    imgnode.style.visibility = "visible";
    window.setTimeout(bell, 1500, false);
  }
  else
    imgnode.style.visibility = "hidden";
  return;
}