/**

 * AJAX functions

 * 

 * Greyhound - real web management for Amarok

 * Copyright (C) 2008 Dan Fuhry

 *

 * This program is Free Software; you can redistribute and/or modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied

 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for details.

 */

var ajax;

var is_playing = false, current_track = -1, current_track_length, current_track_pos, ct_advance_timeout = false, ct_counter = false, playlist_md5 = false, first_load = true;

var onload_hooks = new Array();

function addOnloadHook(func)

{

  if ( typeof ( func ) == 'function' )

  {

    if ( typeof(onload_hooks.push) == 'function' )

    {

      onload_hooks.push(func);

    }

    else

    {

      onload_hooks[onload_hooks.length] = func;

    }

  }

}

function runOnloadHooks(e)

{

  var _errorTrapper = 0;

  for ( var _oLc = 0; _oLc < onload_hooks.length; _oLc++ )

  {

    _errorTrapper++;

    if ( _errorTrapper >= 1000 )

      break;

    var _f = onload_hooks[_oLc];

    if ( typeof(_f) == 'function' )

    {

      _f(e);

    }

  }

}

function ajaxGet(uri, f)

{

  if (window.XMLHttpRequest)

  {

    ajax = new XMLHttpRequest();

  }

  else

  {

    if (window.ActiveXObject) {           

      ajax = new ActiveXObject("Microsoft.XMLHTTP");

    }

    else

    {

      alert('AmaroK client-side runtime error: No AJAX support, unable to continue');

      return;

    }

  }

  ajax.onreadystatechange = f;

  ajax.open('GET', uri, true);

  ajax.setRequestHeader( "If-Modified-Since", "Sat, 1 Jan 2000 00:00:00 GMT" );

  ajax.send(null);

}

function ajaxPost(uri, parms, f)

{

  if (window.XMLHttpRequest)

  {

    ajax = new XMLHttpRequest();

  }

  else

  {

    if (window.ActiveXObject)

    {           

      ajax = new ActiveXObject("Microsoft.XMLHTTP");

    }

    else

    {

      alert('AmaroK client-side runtime error: No AJAX support, unable to continue');

      return;

    }

  }

  ajax.onreadystatechange = f;

  ajax.open('POST', uri, true);

  ajax.setRequestHeader("Content-type", "application/x-www-form-urlencoded");

  // Setting Content-length in Safari triggers a warning

  if ( !is_Safari )

  {

    ajax.setRequestHeader("Content-length", parms.length);

  }

  ajax.setRequestHeader("Connection", "close");

  ajax.send(parms);

}

function setAjaxLoading()

{

  $('ajax_status').object.src = img_ajax;

  $('ajax_status').object.style.display = 'block';

}

function unsetAjaxLoading()

{

  $('ajax_status').object.src = 'about:blank';

  $('ajax_status').object.style.display = 'none';

}

var refresh_playlist = function()

{

  setAjaxLoading();

  ajaxGet('/action.json/refresh', function()

    {

      if ( ajax.readyState == 4 && ajax.status == 200 )

      {

        unsetAjaxLoading();

        var response = (' ' + ajax.responseText).substr(1);

        // quickie JSON parser :)

        response = eval('(' + response + ')');

        // has the playlist been modified?

        if ( playlist_md5 )

        {

          if ( response.playlist_hash != playlist_md5 )

          {

            // playlist has changed, reload

            window.location.reload();

            return false;

          }

        }

        playlist_md5 = response.playlist_hash;

        // update track number

        if ( response.current_track != current_track )

        {

          var ot_id = 'track_' + current_track;

          var nt_id = 'track_' + response.current_track;

          current_track = response.current_track;

          if ( $(ot_id).hasClass('current') )

          {

            $(ot_id).rmClass('current');

          }

          if ( ! $(nt_id).hasClass('current') )

          {

            $(nt_id).addClass('current');

          }

          pulsar_reset();

        }

        // update playing status

        is_playing = response.is_playing;

        if ( allow_control )

        {

          var img = $('btn_playpause').object.getElementsByTagName('img')[0];

          if ( is_playing )

          {

            img.src = img_pause;

          }

          else

          {

            img.src = img_play;

          }

        }

        // update volume

        if ( response.volume != current_volume )

        {

          set_volume_fill(response.volume);

          current_volume = response.volume;

        }

        // auto-refresh on track advance

        if ( ct_advance_timeout )

        {

          clearTimeout(ct_advance_timeout);

        }

        // countdown/up timer

        var time_remaining = response.current_track_length - response.current_track_pos;

        current_track_length = response.current_track_length;

        current_track_pos = response.current_track_pos;

        if ( ct_counter )

          clearInterval(ct_counter);

        update_clock();

        // set page title

        updateTitle(response.current_track_artist, response.current_track_album, response.current_track_title);

        // if not playing, set the position slider to zero

        {

          posslide_set_position(0);

        }

        // set advance timer

        if ( is_playing && time_remaining > 0 )

        {

          ct_advance_timeout = setTimeout(refresh_playlist, ( 1000 * time_remaining ));

          ct_counter = setInterval(update_clock, 1000);

        }

        if ( first_load )

        {

          first_load = false;

          jump_current_track();

        }

      }

    });

}

function player_action(action)

{

  var act2 = action;

  setAjaxLoading();

  ajaxGet('/action.json/' + action, function()

    {

      if ( ajax.readyState == 4 && ajax.status == 200 )

      {

        unsetAjaxLoading();

        refresh_playlist();

      }

    });

}

function jump_to_song(tid)

{

  setAjaxLoading();

  if ( tid == current_track )

    return false;

  if ( !allow_control )

    return false;

  ajaxGet('/action.json/jump/' + tid, function()

    {

      if ( ajax.readyState == 4 && ajax.status == 200 )

      {

        unsetAjaxLoading();

        var response = (' ' + ajax.responseText).substr(1);

        // quickie JSON parser :)

        response = eval('(' + response + ')');

        // update track number

        var ot_id = 'track_' + current_track;

        var nt_id = 'track_' + tid;

        current_track = tid;

        if ( $(ot_id).hasClass('current') )

        {

          $(ot_id).rmClass('current');

        }

        if ( ! $(nt_id).hasClass('current') )

        {

          $(nt_id).addClass('current');

        }

        // update pulsar

        pulsar_reset();

        // update playing status

        var img = $('btn_playpause').object.getElementsByTagName('img')[0];

        is_playing = true;

        img.src = img_play;

        // auto-refresh on track advance

        if ( ct_advance_timeout )

        {

          clearTimeout(ct_advance_timeout);

        }

        if ( ct_counter )

          clearInterval(ct_counter);

        var time_remaining = response.current_track_length - response.current_track_pos;

        current_track_length = response.current_track_length;

        current_track_pos = response.current_track_pos;

        if ( is_playing )

        {

          ct_advance_timeout = setTimeout(refresh_playlist, ( 1000 * time_remaining ));

          update_clock();

          ct_counter = setInterval(update_clock, 1000);

        }

        updateTitle(response.current_track_artist, response.current_track_album, response.current_track_title);

      }

    });

}

function set_playback_position(pos)

{

  pos = Math.round(( pos / 100 ) * current_track_length);

  setAjaxLoading();

  if ( !allow_control )

    return false;

  ajaxGet('/action.json/seek/' + pos, function()

    {

      if ( ajax.readyState == 4 && ajax.status == 200 )

      {

        unsetAjaxLoading();

        current_track_pos = pos;

        update_clock();

      }

    });

}

function update_clock()

{

  posslide_set_position((100 * (current_track_pos / current_track_length)));

  var str = secs_to_string(current_track_pos) + '/' + secs_to_string(current_track_length);

  $('playmeter').object.innerHTML = str;

  current_track_pos++;

}

function secs_to_string(time)

{

  var count_seconds = time % 60;

  var count_minutes = ( time - count_seconds ) / 60;

  if ( isNaN(count_seconds) )

    count_seconds = 0;

  if ( isNaN(count_minutes) )

    count_minutes = 0;

  return fill_zeroes(count_minutes) + ':' + fill_zeroes(count_seconds);

}

function fill_zeroes(str, len)

{

  if ( !len )

    len = 2;

  if ( typeof(str) == 'number' && str == 0 )

    str = '0';

  str = String(str);

  while ( str.length < len )

  {

    str = '0' + str;

  }

  return str;

}

setInterval(refresh_playlist, 10000);

window.onload = function(e)

{

  runOnloadHooks(e);

}

addOnloadHook(refresh_playlist);

// scroll to the current track

function jump_current_track()

{

  var top = $('track_' + current_track).Top() - 138;

  window.scroll(0, top);

  if ( typeof(fix_scroll) == 'function' )

  {

    fix_scroll();

  }

}

// pulse the current track

var pulsar_current = 0, pulsar_tdlist = [], pulsar_direction = 1;

var pulsar_reset = function()

{

  // remove any pulsar classes from items that aren't "current"

  var boobylist = document.getElementsByTagName('tr');

  for ( var i = 0; i < boobylist.length; i++ )

  {

    var booby = boobylist[i];

    var match = booby.className.match(/(^| )(pulsar[0-9])( |$)/);

    if ( match && !$(booby).hasClass('current') )

    {

      $(booby).rmClass(match[2]);

    }

  }

  // recalculate list of rows that should pulse

  var tdlist_new = document.getElementsByClassName('current', 'tr');

  if ( pulsar_current == 0 && tdlist_new == pulsar_tdlist )

  {

    return true;

  }

  // reset everything to 0

  pulsar_tdlist = tdlist_new;

  pulsar_current = 0;

  pulsar_direction = 1;

  for ( var i = 0; i < pulsar_tdlist.length; i++ )

  {

    var td = pulsar_reset[i];

    for ( var i = 1; i < 10; i++ )

    {

      if ( $(td).hasClass('pulsar' + i) )

      {

        $(td).rmClass('pulsar' + i);

      }

    }

    if ( ! $(td).hasClass('pulsar0') )

    {

      $(td).addClass('pulsar0');

    }

  }

}

var pulsar_advance = function()

{

  // this should be as optimized as possible, it should use a precalculated

  // list of elements to pulse and whatnot... heck even right now it's not

  // really as optimized as it should be due to the logic, but a lot of it's

  // kinda more or less necessary.

  if ( !is_playing )

    return true;

  if ( pulsar_current + pulsar_direction == 10 )

  {

    pulsar_direction = -1;

  }

  else if ( pulsar_current + pulsar_direction == -1 )

  {

    pulsar_direction = 1;

  }

  var nc = pulsar_current + pulsar_direction;

  for ( var i = 0; i < pulsar_tdlist.length; i++ )

  {

    $(pulsar_tdlist[i]).rmClass('pulsar' + pulsar_current).addClass('pulsar' + nc);

  }

  pulsar_current = nc;

}

addOnloadHook(pulsar_reset);

setInterval(pulsar_advance, 50);

function updateTitle(artist, album, track)

{

  var sep = '';

  var str = '';

  if ( track )

  {

    str += sep + track;

    sep = ' - ';

  }

  if ( artist )

  {

    str += sep + artist;

    sep = ' - ';

  }

  if ( album )

  {

    str += sep + album;

    sep = ' - ';

  }

  str += sep + 'AmaroK Playlist';

  document.title = str;

}