/*!
 * jQCloud Plugin for jQuery
 *
 * Version 0.1.8
 *
 * Copyright 2011, Luca Ongaro
 * Licensed under the MIT license.
 *
 * Date: Fri Apr 8 10:24:15 +0100 2011
 */ 
 
(function( $ ){
  $.fn.jQCloud = function(word_array, callback_function, config) {
    // Reference to the container element
    var $this = this;
    // Reference to the ID of the container element
    var container_id = $this.attr('id');

    // Add the "jqcloud" class to the container for easy CSS styling
    $this.addClass("jqcloud");

    config = (!config ? {} : config);
    var placement_interval = config['placement_interval'];
    var random_colors = config['random_colors'];
    var min_font_size = config['min_font_size'];
    var max_font_size = config['max_font_size'];

    var drawWordCloud = function() {
      // Helper function to test if an element overlaps others
      var hitTest = function(elem, other_elems){
        // Pairwise overlap detection
        var overlapping = function(a, b){
          if (Math.abs(2.0*a.offsetLeft + a.offsetWidth - 2.0*b.offsetLeft - b.offsetWidth) < a.offsetWidth + b.offsetWidth) {
            if (Math.abs(2.0*a.offsetTop + a.offsetHeight - 2.0*b.offsetTop - b.offsetHeight) < a.offsetHeight + b.offsetHeight) {
              return true;
            }
          }
          return false;
        };
        var i = 0;
        // Check elements for overlap one by one, stop and return false as soon as an overlap is found
        for(i = 0; i < other_elems.length; i++) {
          if (overlapping(elem, other_elems[i])) {
            return true;
          }
        }
        return false;
      };

      // Make sure every weight is a number before sorting
      for (i = 0; i < word_array.length; i++) {
        word_array[i].weight = parseFloat(word_array[i].weight, 10);
      }

      // Sort word_array from the word with the highest weight to the one with the lowest
      word_array.sort(function(a, b) { if (a.weight < b.weight) {return 1;} else if (a.weight > b.weight) {return -1;} else {return 0;} });

      var step = 2.0;
      var already_placed_words = [];
      var aspect_ratio = $this.width() / $this.height();
      var origin_x = $this.width() / 2.0;
      var origin_y = $this.height() / 2.0;

      // Move each word in spiral until it finds a suitable empty place
      var place_one_word = function(index, word) {

        // Define the ID attribute of the span that will wrap the word, and the associated jQuery selector string
        var word_id = container_id + "_word_" + index;
        var word_selector = "#" + word_id;

        var angle = 6.28 * Math.random();
        var radius = 0.0;

        // Linearly map the original weight to a discrete scale from 1 to 10
        var weight = Math.round((word.weight - word_array[word_array.length - 1].weight)/(word_array[0].weight - word_array[word_array.length - 1].weight) * 9.0) + 1;

        var isArray = function(value){
          var s = typeof value;
          if (s === 'object') {
            if (value) {
              if (value instanceof Array) {
                return true;
              }
            }
          }
          return false;
        };
        var style_vals = "";
        if(random_colors && isArray(random_colors)){
          var random_color = random_colors[Math.floor(Math.random()*random_colors.length)];
          style_vals += "color:" + random_color + ";";
        }
        if(min_font_size && max_font_size){
          var font_size = Math.round(
              (word.weight - word_array[word_array.length - 1].weight) / 
              ((word_array[0].weight - word_array[word_array.length - 1].weight) * 1.0) * 
              (max_font_size - min_font_size)
          ) + min_font_size;
          style_vals += "font-size:" + font_size + "px;";
        }

        var inner_html = word.url !== undefined ? "<a href='" + encodeURI(word.url).replace(/'/g, "%27") + "'>" + word.text + "</a>" : word.text;
        $this.append("<span id='" + word_id + "' class='w" + weight + "' title='" + (word.title || "") + "' style='" + style_vals + "'>" + inner_html + "</span>");

        var width = $(word_selector).width();
        var height = $(word_selector).height();
        var left = origin_x - width / 2.0;
        var top = origin_y - height / 2.0;
        $(word_selector).css("position", "absolute");
        $(word_selector).css("left", left + "px");
        $(word_selector).css("top", top + "px");

        while(hitTest(document.getElementById(word_id), already_placed_words)) {
          radius += step;
          angle += (index % 2 === 0 ? 1 : -1)*step;

          left = origin_x - (width / 2.0) + (radius*Math.cos(angle)) * aspect_ratio;
          top = origin_y + radius*Math.sin(angle) - (height / 2.0);

          $(word_selector).css('left', left + "px");
          $(word_selector).css('top', top + "px");
        }
        already_placed_words.push(document.getElementById(word_id));
      };

      var interval = 0;
      if (placement_interval && (interval = parseInt(placement_interval))) {
        if(word_array.length > 0){
          var place_words_one_by_one = function(index, word){
            place_one_word(index, word);

            if (typeof callback_function === 'function') {
              callback_function.call(this, index, word);
            }

            var next_index = index + 1;
            if(next_index < word_array.length){
              setTimeout(function(){place_words_one_by_one(next_index, word_array[next_index]);}, interval);
            }
          }

          place_words_one_by_one(0, word_array[0]);
        }
      } else {
        $.each(word_array, function(index, word) {
          place_one_word(index, word);
        });

        if (typeof callback_function === 'function') {
          callback_function.call(this);
        }
      }

    };

    // Delay execution so that the browser can render the page before the computatively intensive word cloud drawing
    setTimeout(function(){drawWordCloud();}, 300);
    return this;
  };
})(jQuery);