// Dynamically set the css background images for all the sprites
define([
  'skin-sprites',
  'font',
  'visualizer',
  'vendor/jszip.2.4.0.min'
], function(
  SKIN_SPRITES,
  Font,
  Visualizer,
  JSZip
) {
  return {
    font: Font,
    init: function(visualizerNode, analyser) {
      this._createNewStyleNode();
      this.visualizer = Visualizer.init(visualizerNode, analyser);
      return this;
    },

    // For sprites that tile, we need to use just the sprite, not the whole image
    _skinSprites: SKIN_SPRITES,

    // Given a file of an original Winamp WSZ file, set the current skin
    setSkinByFile: function(file, completedCallback) {
      this.completedCallback = completedCallback;
      file.processBuffer(this._setSkinByBuffer.bind(this));
    },

    // Given a bufferArray containing a Winamp WSZ file, set the current skin
    // Gets passed as a callback, so don't have access to `this`
    _setSkinByBuffer: function(buffer) {
      var zip = new JSZip(buffer);
      document.getElementById('time').classList.remove('ex');

      var promisedCssRules = this._skinSprites.map(function(spriteObj) {

        var file = this._findFileInZip(spriteObj.img, zip);
        if (file) {
          // CSS has to change if this file is present
          if (spriteObj.img === 'NUMS_EX') {
            document.getElementById('time').classList.add('ex');
          }
          var src = 'data:image/bmp;base64,' + btoa(file.asBinary());
          return this._spriteCssRule(src, spriteObj);
        }
      }, this);

      // Extract sprite images
      Promise.all(promisedCssRules).then(function(newCssRules) {
        this._createNewStyleNode();
        var cssRules = newCssRules.join('\n');
        this.styleNode.appendChild(document.createTextNode(cssRules));
        this._parseVisColors(zip);
        if (this.completedCallback !== void 0) {
          this.completedCallback();
        }
      }.bind(this));
    },

    _parseVisColors: function(zip) {
      var entries = this._findFileInZip('VISCOLOR.TXT', zip).asText().split('\n');
      var regex = /^(\d+)\s*,\s*(\d+)\s*,\s*(\d+)/;
      var colors = [];
      // changed to a hard number to deal with empty lines at the end...
      // plus its only meant to be an exact amount of numbers anywayz
      // - @PAEz
      for (var i = 0; i < 24; i++) {
        var matches = regex.exec(entries[i]);
        if (matches) {
          colors[i] = 'rgb(' + matches.slice(1, 4).join(',') + ')';
        } else {
          console.error('Error in VISCOLOR.TXT on line', i);
        }
      }
      this.visualizer.setColors(colors);
    },

    _findFileInZip: function(name, zip) {
      // Note: "."s in file names are actually treated as wildcards
      return zip.file(new RegExp('(/|^)' + name, 'i'))[0];
    },

    _createNewStyleNode: function() {
      if (this.styleNode) {
        document.head.removeChild(this.styleNode);
      }
      this.styleNode = document.createElement('style');
      document.head.appendChild(this.styleNode);
    },

    // Given an image URL and coordinates, returns a data url for a sub-section
    // of that image
    _spriteCssRule: function(src, spriteObj) {
      return new Promise(function(resolve) {
        var imageObj = new Image();
        imageObj.src = src;

        imageObj.onload = function() {
          var skinImage = this;
          var cssRules = '';
          var canvas = document.createElement('canvas');
          spriteObj.sprites.forEach(function(sprite) {
            canvas.height = sprite.height;
            canvas.width = sprite.width;

            var context = canvas.getContext('2d');
            context.drawImage(skinImage, -sprite.x, -sprite.y);
            var value = 'background-image: url(' + canvas.toDataURL() + ')';
            sprite.selectors.forEach(function(selector) {
              cssRules += '#winamp2-js ' + selector + '{' + value + '}\n';
            });
          });
          resolve(cssRules);
        };
      });
    }
  };
});