// Peity jQuery plugin version 0.5.0
// (c) 2011 Ben Pickles
//
// http://benpickles.github.com/peity/
//
// Released under MIT license.
(function($, document) {
  var peity = $.fn.peity = function(type, options) {
    if (document.createElement("canvas").getContext) {
      this.each(function() {
        $(this).change(function() {
          var opts = $.extend({}, options)
          var self = this

          $.each(opts, function(name, value) {
            if ($.isFunction(value)) opts[name] = value.call(self)
          })

          var value = $(this).html();
          peity.graphers[type].call(this, $.extend({}, peity.defaults[type], opts));
          $(this).trigger("chart:changed", value);
        }).trigger("change");
      });
    }

    return this;
  };

  peity.graphers = {};
  peity.defaults = {};

  peity.add = function(type, defaults, grapher){
    peity.graphers[type] = grapher;
    peity.defaults[type] = defaults;
  };

  var devicePixelRatio = window.devicePixelRatio || 1

  function createCanvas(width, height) {
    var canvas = document.createElement("canvas")
    canvas.setAttribute("width", width * devicePixelRatio)
    canvas.setAttribute("height", height * devicePixelRatio)

    if (devicePixelRatio != 1) {
      var style = "width:" + width + "px;height:" + height + "px"
      canvas.setAttribute("style", style)
    }

    return canvas
  }

  peity.add(
    'pie',
    {
      colours: ['#FFF4DD', '#FF9900'],
      delimeter: '/',
      diameter: 16
    },
    function(opts) {
      var $this = $(this)
      var values = $this.text().split(opts.delimeter)
      var v1 = parseFloat(values[0]);
      var v2 = parseFloat(values[1]);
      var adjust = -Math.PI / 2;
      var slice = (v1 / v2) * Math.PI * 2;

      var canvas = createCanvas(opts.diameter, opts.diameter)
      var context = canvas.getContext("2d");
      var centre = canvas.width / 2;

      // Plate.
      context.beginPath();
      context.moveTo(centre, centre);
      context.arc(centre, centre, centre, slice + adjust, (slice == 0) ? Math.PI * 2 : adjust, false);
      context.fillStyle = opts.colours[0];
      context.fill();

      // Slice of pie.
      context.beginPath();
      context.moveTo(centre, centre);
      context.arc(centre, centre, centre, adjust, slice + adjust, false);
      context.fillStyle = opts.colours[1];
      context.fill();

      $this.wrapInner($("<span>").hide()).append(canvas)
  });

  peity.add(
    "line",
    {
      colour: "#c6d9fd",
      strokeColour: "#4d89f9",
      strokeWidth: 1,
      delimeter: ",",
      height: 16,
      max: null,
      width: 32
    },
    function(opts) {
      var $this = $(this)
      var canvas = createCanvas(opts.width, opts.height)
      var values = $this.text().split(opts.delimeter)
      if (values.length == 1) values.push(values[0])
      var max = Math.max.apply(Math, values.concat([opts.max]));

      var context = canvas.getContext("2d");
      var width = canvas.width
      var height = canvas.height
      var ratio = height / max;
      var point_width = width / (values.length - 1);
      var coords = [];
      var i;

      context.beginPath();
      context.moveTo(0, height);

      for (i = 0; i < values.length; i++) {
        var point_height = ratio * values[i];
        var x = i * point_width;
        var y = height - point_height;
        coords.push({ x: x, y: y });
        context.lineTo(x, y);
      }

      context.lineTo(width, height);
      context.fillStyle = opts.colour;
      context.fill();

      if (opts.strokeWidth) {
        context.beginPath();
        context.moveTo(0, coords[0].y);
        for (i = 0; i < coords.length; i++) {
          context.lineTo(coords[i].x, coords[i].y);
        }
        context.lineWidth = opts.strokeWidth * devicePixelRatio;
        context.strokeStyle = opts.strokeColour;
        context.stroke();
      }

      $this.wrapInner($("<span>").hide()).append(canvas)
    }
  );

  peity.add(
    'bar',
    {
      colour: "#4D89F9",
      delimeter: ",",
      height: 16,
      max: null,
      width: 32
    },
    function(opts) {
      var $this = $(this)
      var values = $this.text().split(opts.delimeter)
      var max = Math.max.apply(Math, values.concat([opts.max]));

      var canvas = createCanvas(opts.width, opts.height)
      var context = canvas.getContext("2d");

      var width = canvas.width
      var height = canvas.height
      var ratio = height / max;
      var bar_width = width / values.length;

      context.fillStyle = opts.colour;

      for (var i = 0; i < values.length; i++) {
        var bar_height = ratio * values[i];
        var x = i * bar_width;
        var y = height - bar_height;

        context.fillRect(x, y, bar_width, bar_height);
      }

      $this.wrapInner($("<span>").hide()).append(canvas)
    }
  );
})(jQuery, document);
