/*
 * Copyright (c) 2011 TWIMPACT UG (haftungsbeschraenkt). All rights reserved.
 */


(function($) {

  /*
   * Default configuration settings
   */
  var defaults = {
    // Settings common to most/all chart types
    common: {
      type : 'line',
      lineColor : '#00f',
      fillColor : '#cdf',
      defaultPixelsPerValue : 3,
      width : 'auto',
      height : 'auto',
      composite : false,
      tagValuesAttribute: 'values',
      tagOptionsPrefix: 'spark',
      enableTagOptions: false
    },
    // Defaults for line charts
    line: {
      spotColor : '#f80',
      spotRadius : 1.5,
      minSpotColor : '#f80',
      maxSpotColor : '#f80',
      lineWidth: 1,
      normalRangeMin : undefined,
      normalRangeMax : undefined,
      normalRangeColor : '#ccc',
      drawNormalOnTop: false,
      chartRangeMin : undefined,
      chartRangeMax : undefined,
      chartRangeMinX : undefined,
      chartRangeMaxX : undefined
    },
    // Defaults for bar charts
    bar: {
      barColor : '#00f',
      negBarColor : '#f44',
      zeroColor: undefined,
      nullColor: undefined,
      zeroAxis : undefined,
      barWidth : 4,
      barSpacing : 1,
      chartRangeMax: undefined,
      chartRangeMin: undefined,
      chartRangeClip: false,
      colorMap : undefined
    },
    // Defaults for tristate charts
    tristate: {
      barWidth : 4,
      barSpacing : 1,
      posBarColor: '#6f6',
      negBarColor : '#f44',
      zeroBarColor : '#999',
      colorMap : {}
    },
    // Defaults for discrete charts
    discrete: {
      lineHeight: 'auto',
      thresholdColor: undefined,
      thresholdValue : 0,
      chartRangeMax: undefined,
      chartRangeMin: undefined,
      chartRangeClip: false
    },
    // Defaults for bullet charts
    bullet: {
      targetColor : 'red',
      targetWidth : 3, // width of the target bar in pixels
      performanceColor : 'blue',
      rangeColors : ['#D3DAFE', '#A8B6FF', '#7F94FF' ],
      base : undefined // set this to a number to change the base start number
    },
    // Defaults for pie charts
    pie: {
      sliceColors : ['#f00', '#0f0', '#00f']
    },
    // Defaults for box plots
    box: {
      raw: false,
      boxLineColor: 'black',
      boxFillColor: '#cdf',
      whiskerColor: 'black',
      outlierLineColor: '#333',
      outlierFillColor: 'white',
      medianColor: 'red',
      showOutliers: true,
      outlierIQR: 1.5,
      spotRadius: 1.5,
      target: undefined,
      targetColor: '#4a2',
      chartRangeMax: undefined,
      chartRangeMin: undefined
    }
  };

  // Provide a cross-browser interface to a few simple drawing primitives
  var VCanvas_base, VCanvas_canvas, VCanvas_vml;
  $.fn.simpledraw = function(width, height, use_existing) {
    if (use_existing && this[0].VCanvas) {
      return this[0].VCanvas;
    }
    if (width === undefined) {
      width = $(this).innerWidth();
    }
    if (height === undefined) {
      height = $(this).innerHeight();
    }
    if ($.browser.hasCanvas) {
      return new VCanvas_canvas(width, height, this);
    } else if ($.browser.msie) {
      return new VCanvas_vml(width, height, this);
    } else {
      return false;
    }
  };

  var pending = [];


  $.fn.sparkline = function(uservalues, userOptions) {
    return this.each(function() {
      var options = new $.fn.sparkline.options(this, userOptions);
      var render = function() {
        var values, width, height;
        if (uservalues === 'html' || uservalues === undefined) {
          var vals = this.getAttribute(options.get('tagValuesAttribute'));
          if (vals === undefined || vals === null) {
            vals = $(this).html();
          }
          values = vals.replace(/(^\s*<!--)|(-->\s*$)|\s+/g, '').split(',');
        } else {
          values = uservalues;
        }

        width = options.get('width') == 'auto' ? values.length * options.get('defaultPixelsPerValue') : options
            .get('width');
        if (options.get('height') == 'auto') {
          if (!options.get('composite') || !this.VCanvas) {
            // must be a better way to get the line height
            var tmp = document.createElement('span');
            tmp.innerHTML = 'a';
            $(this).html(tmp);
            height = $(tmp).innerHeight();
            $(tmp).remove();
          }
        } else {
          height = options.get('height');
        }

        $.fn.sparkline[options.get('type')].call(this, values, options, width, height);
      };
      // jQuery 1.3.0 completely changed the meaning of :hidden :-/
      if (($(this).html() && $(this).is(':hidden')) || ($.fn.jquery < "1.3.0" && $(this).parents()
          .is(':hidden')) || !$(this).parents('body').length) {
        pending.push([this, render]);
      } else {
        render.call(this);
      }
    });
  };

  $.fn.sparkline.defaults = defaults;


  $.sparkline_display_visible = function() {
    for (var i = pending.length - 1; i >= 0; i--) {
      var el = pending[i][0];
      if ($(el).is(':visible') && !$(el).parents().is(':hidden')) {
        pending[i][1].call(el);
        pending.splice(i, 1);
      }
    }
  };


  /**
   * User option handler
   */
  var UNSET_OPTION = {};
  var normalizeValue = function(val) {
    switch (val) {
      case 'undefined':
        val = undefined;
        break;
      case 'null':
        val = null;
        break;
      case 'true':
        val = true;
        break;
      case 'false':
        val = false;
        break;
      default:
        var nf = parseFloat(val);
        if (val == nf) {
          val = nf;
        }
    }
    return val;
  };
  $.fn.sparkline.options = function(tag, userOptions) {
    var extendedOptions;
    this.userOptions = userOptions = userOptions || {};
    this.tag = tag;
    this.tagValCache = {};
    var defaults = $.fn.sparkline.defaults;
    var base = defaults.common;
    this.tagOptionsPrefix = userOptions.enableTagOptions && (userOptions.tagOptionsPrefix || base.tagOptionsPrefix);

    var tagOptionType = this.getTagSetting('type');
    if (tagOptionType === UNSET_OPTION) {
      extendedOptions = defaults[userOptions.type || base.type];
    } else {
      extendedOptions = defaults[tagOptionType];
    }
    this.mergedOptions = $.extend({}, base, extendedOptions, userOptions);
  };


  $.fn.sparkline.options.prototype.getTagSetting = function(key) {
    var val, i, prefix = this.tagOptionsPrefix;
    if (prefix === false || prefix === undefined) {
      return UNSET_OPTION;
    }
    if (this.tagValCache.hasOwnProperty(key)) {
      val = this.tagValCache.key;
    } else {
      val = this.tag.getAttribute(prefix + key);
      if (val === undefined || val === null) {
        val = UNSET_OPTION;
      } else if (val.substr(0, 1) == '[') {
        val = val.substr(1, val.length - 2).split(',');
        for (i = val.length; i--;) {
          val[i] = normalizeValue(val[i].replace(/(^\s*)|(\s*$)/g, ''));
        }
      } else if (val.substr(0, 1) == '{') {
        var pairs = val.substr(1, val.length - 2).split(',');
        val = {};
        for (i = pairs.length; i--;) {
          var keyval = pairs[i].split(':', 2);
          val[keyval[0].replace(/(^\s*)|(\s*$)/g, '')] = normalizeValue(keyval[1].replace(/(^\s*)|(\s*$)/g, ''));
        }
      } else {
        val = normalizeValue(val);
      }
      this.tagValCache.key = val;
    }
    return val;
  };

  $.fn.sparkline.options.prototype.get = function(key) {
    var tagOption = this.getTagSetting(key);
    if (tagOption !== UNSET_OPTION) {
      return tagOption;
    }
    return this.mergedOptions[key];
  };


  /**
   * Line charts
   */
  $.fn.sparkline.line = function(values, options, width, height) {
    var xvalues = [], yvalues = [], yminmax = [];
    for (var i = 0; i < values.length; i++) {
      var val = values[i];
      var isstr = typeof(values[i]) == 'string';
      var isarray = typeof(values[i]) == 'object' && values[i] instanceof Array;
      var sp = isstr && values[i].split(':');
      if (isstr && sp.length == 2) { // x:y
        xvalues.push(Number(sp[0]));
        yvalues.push(Number(sp[1]));
        yminmax.push(Number(sp[1]));
      } else if (isarray) {
        xvalues.push(val[0]);
        yvalues.push(val[1]);
        yminmax.push(val[1]);
      } else {
        xvalues.push(i);
        if (values[i] === null || values[i] == 'null') {
          yvalues.push(null);
        } else {
          yvalues.push(Number(val));
          yminmax.push(Number(val));
        }
      }
    }
    if (options.get('xvalues')) {
      xvalues = options.get('xvalues');
    }

    var maxy = Math.max.apply(Math, yminmax);
    var maxyval = maxy;
    var miny = Math.min.apply(Math, yminmax);
    var minyval = miny;

    var maxx = Math.max.apply(Math, xvalues);
    var minx = Math.min.apply(Math, xvalues);

    var normalRangeMin = options.get('normalRangeMin');
    var normalRangeMax = options.get('normalRangeMax');

    if (normalRangeMin !== undefined) {
      if (normalRangeMin < miny) {
        miny = normalRangeMin;
      }
      if (normalRangeMax > maxy) {
        maxy = normalRangeMax;
      }
    }
    if (options.get('chartRangeMin') !== undefined && (options.get('chartRangeClip') || options
        .get('chartRangeMin') < miny)) {
      miny = options.get('chartRangeMin');
    }
    if (options.get('chartRangeMax') !== undefined && (options.get('chartRangeClip') || options
        .get('chartRangeMax') > maxy)) {
      maxy = options.get('chartRangeMax');
    }
    if (options.get('chartRangeMinX') !== undefined && (options.get('chartRangeClipX') || options
        .get('chartRangeMinX') < minx)) {
      minx = options.get('chartRangeMinX');
    }
    if (options.get('chartRangeMaxX') !== undefined && (options.get('chartRangeClipX') || options
        .get('chartRangeMaxX') > maxx)) {
      maxx = options.get('chartRangeMaxX');
    }
    var rangex = maxx - minx === 0 ? 1 : maxx - minx;
    var rangey = maxy - miny === 0 ? 1 : maxy - miny;
    var vl = yvalues.length - 1;

    if (vl < 1) {
      this.innerHTML = '';
      return;
    }

    var target = $(this).simpledraw(width, height, options.get('composite'));
    if (target) {
      var canvas_width = target.pixel_width;
      var canvas_height = target.pixel_height;
      var canvas_top = 0;
      var canvas_left = 0;

      var spotRadius = options.get('spotRadius');
      if (spotRadius && (canvas_width < (spotRadius * 4) || canvas_height < (spotRadius * 4))) {
        spotRadius = 0;
      }
      if (spotRadius) {
        // adjust the canvas size as required so that spots will fit
        if (options.get('minSpotColor') || (options.get('spotColor') && yvalues[vl] == miny)) {
          canvas_height -= Math.ceil(spotRadius);
        }
        if (options.get('maxSpotColor') || (options.get('spotColor') && yvalues[vl] == maxy)) {
          canvas_height -= Math.ceil(spotRadius);
          canvas_top += Math.ceil(spotRadius);
        }
        if (options.get('minSpotColor') || options.get('maxSpotColor') && (yvalues[0] == miny || yvalues[0] == maxy)) {
          canvas_left += Math.ceil(spotRadius);
          canvas_width -= Math.ceil(spotRadius);
        }
        if (options.get('spotColor') || (options.get('minSpotColor') || options
            .get('maxSpotColor') && (yvalues[vl] == miny || yvalues[vl] == maxy))) {
          canvas_width -= Math.ceil(spotRadius);
        }
      }


      canvas_height--;

      var drawNormalRange = function() {
        if (normalRangeMin !== undefined) {
          var ytop = canvas_top + Math.round(canvas_height - (canvas_height * ((normalRangeMax - miny) / rangey)));
          var height = Math.round((canvas_height * (normalRangeMax - normalRangeMin)) / rangey);
          target.drawRect(canvas_left, ytop, canvas_width, height, undefined, options.get('normalRangeColor'));
        }
      };

      if (!options.get('drawNormalOnTop')) {
        drawNormalRange();
      }

      var path = [];
      var paths = [path];
      var x, y, vlen = yvalues.length;
      for (i = 0; i < vlen; i++) {
        x = xvalues[i];
        y = yvalues[i];
        if (y === null) {
          if (i) {
            if (yvalues[i - 1] !== null) {
              path = [];
              paths.push(path);
            }
          }
        } else {
          if (y < miny) {
            y = miny;
          }
          if (y > maxy) {
            y = maxy;
          }
          if (!path.length) {
            // previous value was null
            path.push([canvas_left + Math.round((x - minx) * (canvas_width / rangex)), canvas_top + canvas_height]);
          }
          path.push([canvas_left + Math.round((x - minx) * (canvas_width / rangex)), canvas_top + Math
              .round(canvas_height - (canvas_height * ((y - miny) / rangey)))]);
        }
      }
      var lineshapes = [];
      var fillshapes = [];
      var plen = paths.length;
      for (i = 0; i < plen; i++) {
        path = paths[i];
        if (!path.length) {
          continue; // last value was null
        }
        if (options.get('fillColor')) {
          path.push([path[path.length - 1][0], canvas_top + canvas_height - 1]);
          fillshapes.push(path.slice(0));
          path.pop();
        }
        // if there's only a single point in this path, then we want to display it as a vertical line
        // which means we keep path[0]  as is
        if (path.length > 2) {
          // else we want the first value
          path[0] = [ path[0][0], path[1][1] ];
        }
        lineshapes.push(path);
      }

      // draw the fill first, then optionally the normal range, then the line on top of that
      plen = fillshapes.length;
      for (i = 0; i < plen; i++) {
        target.drawShape(fillshapes[i], undefined, options.get('fillColor'));
      }

      if (options.get('drawNormalOnTop')) {
        drawNormalRange();
      }

      plen = lineshapes.length;
      for (i = 0; i < plen; i++) {
        target.drawShape(lineshapes[i], options.get('lineColor'), undefined, options.get('lineWidth'));
      }

      if (spotRadius && options.get('spotColor')) {
        target.drawCircle(canvas_left + Math.round(xvalues[xvalues
            .length - 1] * (canvas_width / rangex)), canvas_top + Math
            .round(canvas_height - (canvas_height * ((yvalues[vl] - miny) / rangey))), spotRadius, undefined, options
            .get('spotColor'));
      }
      if (maxy != minyval) {
        if (spotRadius && options.get('minSpotColor')) {
          x = xvalues[$.inArray(minyval, yvalues)];
          target.drawCircle(canvas_left + Math.round((x - minx) * (canvas_width / rangex)), canvas_top + Math
              .round(canvas_height - (canvas_height * ((minyval - miny) / rangey))), spotRadius, undefined, options
              .get('minSpotColor'));
        }
        if (spotRadius && options.get('maxSpotColor')) {
          x = xvalues[$.inArray(maxyval, yvalues)];
          target.drawCircle(canvas_left + Math.round((x - minx) * (canvas_width / rangex)), canvas_top + Math
              .round(canvas_height - (canvas_height * ((maxyval - miny) / rangey))), spotRadius, undefined, options
              .get('maxSpotColor'));
        }
      }

    } else {
      // Remove the tag contents if sparklines aren't supported
      this.innerHTML = '';
    }
  };


  /**
   * Bar charts
   */
  $.fn.sparkline.bar = function(values, options, width, height) {
    width = (values.length * options.get('barWidth')) + ((values.length - 1) * options.get('barSpacing'));
    var num_values = [];
    for (var i = 0, vlen = values.length; i < vlen; i++) {
      if (values[i] == 'null' || values[i] === null) {
        values[i] = null;
      } else {
        values[i] = Number(values[i]);
        num_values.push(Number(values[i]));
      }
    }
    var max = Math.max.apply(Math, num_values),
        min = Math.min.apply(Math, num_values);
    if (options.get('chartRangeMin') !== undefined && (options.get('chartRangeClip') || options
        .get('chartRangeMin') < min)) {
      min = options.get('chartRangeMin');
    }
    if (options.get('chartRangeMax') !== undefined && (options.get('chartRangeClip') || options
        .get('chartRangeMax') > max)) {
      max = options.get('chartRangeMax');
    }
    var zeroAxis = options.get('zeroAxis');
    if (zeroAxis === undefined) {
      zeroAxis = min < 0;
    }
    var range = max - min === 0 ? 1 : max - min;

    var colorMapByIndex, colorMapByValue;
    if ($.isArray(options.get('colorMap'))) {
      colorMapByIndex = options.get('colorMap');
      colorMapByValue = null;
    } else {
      colorMapByIndex = null;
      colorMapByValue = options.get('colorMap');
    }

    var target = $(this).simpledraw(width, height, options.get('composite'));
    if (target) {
      var color,
          canvas_height = target.pixel_height,
          yzero = min < 0 && zeroAxis ? canvas_height - Math.round(canvas_height * (Math
              .abs(min) / range)) - 1 : canvas_height - 1;

      for (i = values.length; i--;) {
        var x = i * (options.get('barWidth') + options.get('barSpacing')),
            y,
            val = values[i];
        if (val === null) {
          if (options.get('nullColor')) {
            color = options.get('nullColor');
            val = (zeroAxis && min < 0) ? 0 : min;
            height = 1;
            y = (zeroAxis && min < 0) ? yzero : canvas_height - height;
          } else {
            continue;
          }
        } else {
          if (val < min) {
            val = min;
          }
          if (val > max) {
            val = max;
          }
          color = (val < 0) ? options.get('negBarColor') : options.get('barColor');
          if (zeroAxis && min < 0) {
            height = Math.round(canvas_height * ((Math.abs(val) / range))) + 1;
            y = (val < 0) ? yzero : yzero - height;
          } else {
            height = Math.round(canvas_height * ((val - min) / range)) + 1;
            y = canvas_height - height;
          }
          if (val === 0 && options.get('zeroColor') !== undefined) {
            color = options.get('zeroColor');
          }
          if (colorMapByValue && colorMapByValue[val]) {
            color = colorMapByValue[val];
          } else if (colorMapByIndex && colorMapByIndex.length > i) {
            color = colorMapByIndex[i];
          }
          if (color === null) {
            continue;
          }
        }
        target.drawRect(x, y, options.get('barWidth') - 1, height - 1, color, color);
      }
    } else {
      // Remove the tag contents if sparklines aren't supported
      this.innerHTML = '';
    }
  };


  /**
   * Tristate charts
   */
  $.fn.sparkline.tristate = function(values, options, width, height) {
    values = $.map(values, Number);
    width = (values.length * options.get('barWidth')) + ((values.length - 1) * options.get('barSpacing'));

    var colorMapByIndex, colorMapByValue;
    if ($.isArray(options.get('colorMap'))) {
      colorMapByIndex = options.get('colorMap');
      colorMapByValue = null;
    } else {
      colorMapByIndex = null;
      colorMapByValue = options.get('colorMap');
    }

    var target = $(this).simpledraw(width, height, options.get('composite'));
    if (target) {
      var canvas_height = target.pixel_height,
          half_height = Math.round(canvas_height / 2);

      for (var i = values.length; i--;) {
        var x = i * (options.get('barWidth') + options.get('barSpacing')),
            y, color;
        if (values[i] < 0) {
          y = half_height;
          height = half_height - 1;
          color = options.get('negBarColor');
        } else if (values[i] > 0) {
          y = 0;
          height = half_height - 1;
          color = options.get('posBarColor');
        } else {
          y = half_height - 1;
          height = 2;
          color = options.get('zeroBarColor');
        }
        if (colorMapByValue && colorMapByValue[values[i]]) {
          color = colorMapByValue[values[i]];
        } else if (colorMapByIndex && colorMapByIndex.length > i) {
          color = colorMapByIndex[i];
        }
        if (color === null) {
          continue;
        }
        target.drawRect(x, y, options.get('barWidth') - 1, height - 1, color, color);
      }
    } else {
      // Remove the tag contents if sparklines aren't supported
      this.innerHTML = '';
    }
  };


  /**
   * Discrete charts
   */
  $.fn.sparkline.discrete = function(values, options, width, height) {
    values = $.map(values, Number);
    width = options.get('width') == 'auto' ? values.length * 2 : width;
    var interval = Math.floor(width / values.length);

    var target = $(this).simpledraw(width, height, options.get('composite'));
    if (target) {
      var canvas_height = target.pixel_height,
          line_height = options.get('lineHeight') == 'auto' ? Math.round(canvas_height * 0.3) : options
              .get('lineHeight'),
          pheight = canvas_height - line_height,
          min = Math.min.apply(Math, values),
          max = Math.max.apply(Math, values);
      if (options.get('chartRangeMin') !== undefined && (options.get('chartRangeClip') || options
          .get('chartRangeMin') < min)) {
        min = options.get('chartRangeMin');
      }
      if (options.get('chartRangeMax') !== undefined && (options.get('chartRangeClip') || options
          .get('chartRangeMax') > max)) {
        max = options.get('chartRangeMax');
      }
      var range = max - min;

      for (var i = values.length; i--;) {
        var val = values[i];
        if (val < min) {
          val = min;
        }
        if (val > max) {
          val = max;
        }
        var x = (i * interval),
            ytop = Math.round(pheight - pheight * ((val - min) / range));
        target.drawLine(x, ytop, x, ytop + line_height, (options.get('thresholdColor') && val < options
            .get('thresholdValue')) ? options.get('thresholdColor') : options.get('lineColor'));
      }
    } else {
      // Remove the tag contents if sparklines aren't supported
      this.innerHTML = '';
    }

  };


  /**
   * Bullet charts
   */
  $.fn.sparkline.bullet = function(values, options, width, height) {
    values = $.map(values, Number);
    // target, performance, range1, range2, range3

    width = options.get('width') == 'auto' ? '4.0em' : width;

    var target = $(this).simpledraw(width, height, options.get('composite'));
    if (target && values.length > 1) {
      var canvas_width = target.pixel_width - Math.ceil(options.get('targetWidth') / 2),
          canvas_height = target.pixel_height,
          min = Math.min.apply(Math, values),
          max = Math.max.apply(Math, values);

      if (options.get('base') === undefined) {
        min = min < 0 ? min : 0;
      } else {
        min = options.get('base');
      }
      var range = max - min;

      // draw range values
      for (var i = 2, vlen = values.length; i < vlen; i++) {
        var rangeval = values[i],
            rangewidth = Math.round(canvas_width * ((rangeval - min) / range));
        target.drawRect(0, 0, rangewidth - 1, canvas_height - 1, options.get('rangeColors')[i - 2], options
            .get('rangeColors')[i - 2]);
      }

      // draw the performance bar
      var perfval = values[1],
          perfwidth = Math.round(canvas_width * ((perfval - min) / range));
      target.drawRect(0, Math.round(canvas_height * 0.3), perfwidth - 1, Math.round(canvas_height * 0.4) - 1, options
          .get('performanceColor'), options.get('performanceColor'));

      // draw the target line
      var targetval = values[0],
          x = Math.round(canvas_width * ((targetval - min) / range) - (options.get('targetWidth') / 2)),
          targettop = Math.round(canvas_height * 0.10),
          targetheight = canvas_height - (targettop * 2);
      target.drawRect(x, targettop, options.get('targetWidth') - 1, targetheight - 1, options
          .get('targetColor'), options.get('targetColor'));
    } else {
      // Remove the tag contents if sparklines aren't supported
      this.innerHTML = '';
    }
  };


  /**
   * Pie charts
   */
  $.fn.sparkline.pie = function(values, options, width, height) {
    values = $.map(values, Number);
    width = options.get('width') == 'auto' ? height : width;

    var target = $(this).simpledraw(width, height, options.get('composite'));
    if (target && values.length > 1) {
      var canvas_width = target.pixel_width,
          canvas_height = target.pixel_height,
          radius = Math.floor(Math.min(canvas_width, canvas_height) / 2),
          total = 0,
          next = 0,
          circle = 2 * Math.PI;

      for (var i = values.length; i--;) {
        total += values[i];
      }

      if (options.get('offset')) {
        next += (2 * Math.PI) * (options.get('offset') / 360);
      }
      var vlen = values.length;
      for (i = 0; i < vlen; i++) {
        var start = next;
        var end = next;
        if (total > 0) {  // avoid divide by zero
          end = next + (circle * (values[i] / total));
        }
        target.drawPieSlice(radius, radius, radius, start, end, undefined, options.get('sliceColors')[i % options
            .get('sliceColors').length]);
        next = end;
      }
    }
  };


  /**
   * Box plots
   */
  var quartile = function(values, q) {
    if (q == 2) {
      var vl2 = Math.floor(values.length / 2);
      return values.length % 2 ? values[vl2] : (values[vl2] + values[vl2 + 1]) / 2;
    } else {
      var vl4 = Math.floor(values.length / 4);
      return values.length % 2 ? (values[vl4 * q] + values[vl4 * q + 1]) / 2 : values[vl4 * q];
    }
  };

  $.fn.sparkline.box = function(values, options, width, height) {
    values = $.map(values, Number);
    width = options.get('width') == 'auto' ? '4.0em' : width;

    var minvalue = options.get('chartRangeMin') === undefined ? Math.min.apply(Math, values) : options
        .get('chartRangeMin'),
        maxvalue = options.get('chartRangeMax') === undefined ? Math.max.apply(Math, values) : options
            .get('chartRangeMax'),
        target = $(this).simpledraw(width, height, options.get('composite')),
        vlen = values.length,
        lwhisker, loutlier, q1, q2, q3, rwhisker, routlier;

    if (target && values.length > 1) {
      var canvas_width = target.pixel_width,
          canvas_height = target.pixel_height;
      if (options.get('raw')) {
        if (options.get('showOutliers') && values.length > 5) {
          loutlier = values[0];
          lwhisker = values[1];
          q1 = values[2];
          q2 = values[3];
          q3 = values[4];
          rwhisker = values[5];
          routlier = values[6];
        } else {
          lwhisker = values[0];
          q1 = values[1];
          q2 = values[2];
          q3 = values[3];
          rwhisker = values[4];
        }
      } else {
        values.sort(function(a, b) { return a - b; });
        q1 = quartile(values, 1);
        q2 = quartile(values, 2);
        q3 = quartile(values, 3);
        var iqr = q3 - q1;
        if (options.get('showOutliers')) {
          lwhisker = undefined;
          rwhisker = undefined;
          for (var i = 0; i < vlen; i++) {
            if (lwhisker === undefined && values[i] > q1 - (iqr * options.get('outlierIQR'))) {
              lwhisker = values[i];
            }
            if (values[i] < q3 + (iqr * options.get('outlierIQR'))) {
              rwhisker = values[i];
            }
          }
          loutlier = values[0];
          routlier = values[vlen - 1];
        } else {
          lwhisker = values[0];
          rwhisker = values[vlen - 1];
        }
      }

      var unitsize = canvas_width / (maxvalue - minvalue + 1),
          canvas_left = 0;
      if (options.get('showOutliers')) {
        canvas_left = Math.ceil(options.get('spotRadius'));
        canvas_width -= 2 * Math.ceil(options.get('spotRadius'));
        unitsize = canvas_width / (maxvalue - minvalue + 1);
        if (loutlier < lwhisker) {
          target.drawCircle((loutlier - minvalue) * unitsize + canvas_left, canvas_height / 2, options
              .get('spotRadius'), options.get('outlierLineColor'), options.get('outlierFillColor'));
        }
        if (routlier > rwhisker) {
          target.drawCircle((routlier - minvalue) * unitsize + canvas_left, canvas_height / 2, options
              .get('spotRadius'), options.get('outlierLineColor'), options.get('outlierFillColor'));
        }
      }

      // box
      target.drawRect(
          Math.round((q1 - minvalue) * unitsize + canvas_left),
          Math.round(canvas_height * 0.1),
          Math.round((q3 - q1) * unitsize),
          Math.round(canvas_height * 0.8),
          options.get('boxLineColor'),
          options.get('boxFillColor'));
      // left whisker
      target.drawLine(
          Math.round((lwhisker - minvalue) * unitsize + canvas_left),
          Math.round(canvas_height / 2),
          Math.round((q1 - minvalue) * unitsize + canvas_left),
          Math.round(canvas_height / 2),
          options.get('lineColor'));
      target.drawLine(
          Math.round((lwhisker - minvalue) * unitsize + canvas_left),
          Math.round(canvas_height / 4),
          Math.round((lwhisker - minvalue) * unitsize + canvas_left),
          Math.round(canvas_height - canvas_height / 4),
          options.get('whiskerColor'));
      // right whisker
      target.drawLine(Math.round((rwhisker - minvalue) * unitsize + canvas_left),
          Math.round(canvas_height / 2),
          Math.round((q3 - minvalue) * unitsize + canvas_left),
          Math.round(canvas_height / 2),
          options.get('lineColor'));
      target.drawLine(
          Math.round((rwhisker - minvalue) * unitsize + canvas_left),
          Math.round(canvas_height / 4),
          Math.round((rwhisker - minvalue) * unitsize + canvas_left),
          Math.round(canvas_height - canvas_height / 4),
          options.get('whiskerColor'));
      // median line
      target.drawLine(
          Math.round((q2 - minvalue) * unitsize + canvas_left),
          Math.round(canvas_height * 0.1),
          Math.round((q2 - minvalue) * unitsize + canvas_left),
          Math.round(canvas_height * 0.9),
          options.get('medianColor'));
      if (options.get('target')) {
        var size = Math.ceil(options.get('spotRadius'));
        target.drawLine(
            Math.round((options.get('target') - minvalue) * unitsize + canvas_left),
            Math.round((canvas_height / 2) - size),
            Math.round((options.get('target') - minvalue) * unitsize + canvas_left),
            Math.round((canvas_height / 2) + size),
            options.get('targetColor'));
        target.drawLine(
            Math.round((options.get('target') - minvalue) * unitsize + canvas_left - size),
            Math.round(canvas_height / 2),
            Math.round((options.get('target') - minvalue) * unitsize + canvas_left + size),
            Math.round(canvas_height / 2),
            options.get('targetColor'));
      }
    } else {
      // Remove the tag contents if sparklines aren't supported
      this.innerHTML = '';
    }
  };


  // Setup a very simple "virtual canvas" to make drawing the few shapes we need easier
  // This is accessible as $(foo).simpledraw()

  if ($.browser.msie && !document.namespaces.v) {
    document.namespaces.add('v', 'urn:schemas-microsoft-com:vml', '#default#VML');
  }

  if ($.browser.hasCanvas === undefined) {
    var t = document.createElement('canvas');
    $.browser.hasCanvas = t.getContext !== undefined;
  }

  VCanvas_base = function(width, height, target) {
  };

  VCanvas_base.prototype = {
    init : function(width, height, target) {
      this.width = width;
      this.height = height;
      this.target = target;
      if (target[0]) {
        target = target[0];
      }
      target.VCanvas = this;
    },

    drawShape : function(path, lineColor, fillColor, lineWidth) {
      alert('drawShape not implemented');
    },

    drawLine : function(x1, y1, x2, y2, lineColor, lineWidth) {
      return this.drawShape([
        [x1,y1],
        [x2,y2]
      ], lineColor, lineWidth);
    },

    drawCircle : function(x, y, radius, lineColor, fillColor) {
      alert('drawCircle not implemented');
    },

    drawPieSlice : function(x, y, radius, startAngle, endAngle, lineColor, fillColor) {
      alert('drawPieSlice not implemented');
    },

    drawRect : function(x, y, width, height, lineColor, fillColor) {
      alert('drawRect not implemented');
    },

    getElement : function() {
      return this.canvas;
    },

    _insert : function(el, target) {
      $(target).html(el);
    }
  };

  VCanvas_canvas = function(width, height, target) {
    return this.init(width, height, target);
  };

  VCanvas_canvas.prototype = $.extend(new VCanvas_base(), {
    _super : VCanvas_base.prototype,

    init : function(width, height, target) {
      this._super.init(width, height, target);
      this.canvas = document.createElement('canvas');
      if (target[0]) {
        target = target[0];
      }
      target.VCanvas = this;
      $(this.canvas).css({ display:'inline-block', width:width, height:height, verticalAlign:'top' });
      this._insert(this.canvas, target);
      this.pixel_height = $(this.canvas).height();
      this.pixel_width = $(this.canvas).width();
      this.canvas.width = this.pixel_width;
      this.canvas.height = this.pixel_height;
      $(this.canvas).css({width: this.pixel_width, height: this.pixel_height});
    },

    _getContext : function(lineColor, fillColor, lineWidth) {
      var context = this.canvas.getContext('2d');
      if (lineColor !== undefined) {
        context.strokeStyle = lineColor;
      }
      context.lineWidth = lineWidth === undefined ? 1 : lineWidth;
      if (fillColor !== undefined) {
        context.fillStyle = fillColor;
      }
      return context;
    },

    drawShape : function(path, lineColor, fillColor, lineWidth) {
      var context = this._getContext(lineColor, fillColor, lineWidth);
      context.beginPath();
      context.moveTo(path[0][0] + 0.5, path[0][1] + 0.5);
      for (var i = 1, plen = path.length; i < plen; i++) {
        context.lineTo(path[i][0] + 0.5, path[i][1] + 0.5); // the 0.5 offset gives us crisp pixel-width lines
      }
      if (lineColor !== undefined) {
        context.stroke();
      }
      if (fillColor !== undefined) {
        context.fill();
      }
    },

    drawCircle : function(x, y, radius, lineColor, fillColor) {
      var context = this._getContext(lineColor, fillColor);
      context.beginPath();
      context.arc(x, y, radius, 0, 2 * Math.PI, false);
      if (lineColor !== undefined) {
        context.stroke();
      }
      if (fillColor !== undefined) {
        context.fill();
      }
    },

    drawPieSlice : function(x, y, radius, startAngle, endAngle, lineColor, fillColor) {
      var context = this._getContext(lineColor, fillColor);
      context.beginPath();
      context.moveTo(x, y);
      context.arc(x, y, radius, startAngle, endAngle, false);
      context.lineTo(x, y);
      context.closePath();
      if (lineColor !== undefined) {
        context.stroke();
      }
      if (fillColor) {
        context.fill();
      }
    },

    drawRect : function(x, y, width, height, lineColor, fillColor) {
      return this.drawShape([
        [x,y],
        [x + width, y],
        [x + width, y + height],
        [x, y + height],
        [x, y]
      ], lineColor, fillColor);
    }

  });

  VCanvas_vml = function(width, height, target) {
    return this.init(width, height, target);
  };

  VCanvas_vml.prototype = $.extend(new VCanvas_base(), {
    _super : VCanvas_base.prototype,

    init : function(width, height, target) {
      this._super.init(width, height, target);
      if (target[0]) {
        target = target[0];
      }
      target.VCanvas = this;
      this.canvas = document.createElement('span');
      $(this.canvas)
          .css({ display:'inline-block', position: 'relative', overflow:'hidden', width:width, height:height, margin:'0px', padding:'0px', verticalAlign: 'top'});
      this._insert(this.canvas, target);
      this.pixel_height = $(this.canvas).height();
      this.pixel_width = $(this.canvas).width();
      this.canvas.width = this.pixel_width;
      this.canvas.height = this.pixel_height;
      var groupel = '<v:group coordorigin="0 0" coordsize="' + this.pixel_width + ' ' + this.pixel_height + '"' +
          ' style="position:absolute;top:0;left:0;width:' + this.pixel_width + 'px;height=' + this
          .pixel_height + 'px;"></v:group>';
      this.canvas.insertAdjacentHTML('beforeEnd', groupel);
      this.group = $(this.canvas).children()[0];
    },

    drawShape : function(path, lineColor, fillColor, lineWidth) {
      var vpath = [];
      for (var i = 0, plen = path.length; i < plen; i++) {
        vpath[i] = '' + (path[i][0]) + ',' + (path[i][1]);
      }
      var initial = vpath.splice(0, 1);
      lineWidth = lineWidth === undefined ? 1 : lineWidth;
      var stroke = lineColor === undefined ? ' stroked="false" ' : ' strokeWeight="' + lineWidth + '" strokeColor="' + lineColor + '" ';
      var fill = fillColor === undefined ? ' filled="false"' : ' fillColor="' + fillColor + '" filled="true" ';
      var closed = vpath[0] == vpath[vpath.length - 1] ? 'x ' : '';
      var vel = '<v:shape coordorigin="0 0" coordsize="' + this.pixel_width + ' ' + this.pixel_height + '" ' +
          stroke +
          fill +
          ' style="position:absolute;left:0px;top:0px;height:' + this.pixel_height + 'px;width:' + this
          .pixel_width + 'px;padding:0px;margin:0px;" ' +
          ' path="m ' + initial + ' l ' + vpath.join(', ') + ' ' + closed + 'e">' +
          ' </v:shape>';
      this.group.insertAdjacentHTML('beforeEnd', vel);
    },

    drawCircle : function(x, y, radius, lineColor, fillColor) {
      x -= radius + 1;
      y -= radius + 1;
      var stroke = lineColor === undefined ? ' stroked="false" ' : ' strokeWeight="1" strokeColor="' + lineColor + '" ';
      var fill = fillColor === undefined ? ' filled="false"' : ' fillColor="' + fillColor + '" filled="true" ';
      var vel = '<v:oval ' +
          stroke +
          fill +
          ' style="position:absolute;top:' + y + 'px; left:' + x + 'px; width:' + (radius * 2) + 'px; height:' + (radius * 2) + 'px"></v:oval>';
      this.group.insertAdjacentHTML('beforeEnd', vel);

    },

    drawPieSlice : function(x, y, radius, startAngle, endAngle, lineColor, fillColor) {
      if (startAngle == endAngle) {
        return;  // VML seems to have problem when start angle equals end angle.
      }
      if ((endAngle - startAngle) == (2 * Math.PI)) {
        startAngle = 0.0;  // VML seems to have a problem when drawing a full circle that doesn't start 0
        endAngle = (2 * Math.PI);
      }

      var startx = x + Math.round(Math.cos(startAngle) * radius);
      var starty = y + Math.round(Math.sin(startAngle) * radius);
      var endx = x + Math.round(Math.cos(endAngle) * radius);
      var endy = y + Math.round(Math.sin(endAngle) * radius);

      // Prevent very small slices from being mistaken as a whole pie
      if (startx == endx && starty == endy && (endAngle - startAngle) < Math.PI) {
        return;
      }

      var vpath = [  x - radius, y - radius, x + radius, y + radius, startx, starty, endx, endy ];
      var stroke = lineColor === undefined ? ' stroked="false" ' : ' strokeWeight="1" strokeColor="' + lineColor + '" ';
      var fill = fillColor === undefined ? ' filled="false"' : ' fillColor="' + fillColor + '" filled="true" ';
      var vel = '<v:shape coordorigin="0 0" coordsize="' + this.pixel_width + ' ' + this.pixel_height + '" ' +
          stroke +
          fill +
          ' style="position:absolute;left:0px;top:0px;height:' + this.pixel_height + 'px;width:' + this
          .pixel_width + 'px;padding:0px;margin:0px;" ' +
          ' path="m ' + x + ',' + y + ' wa ' + vpath.join(', ') + ' x e">' +
          ' </v:shape>';
      this.group.insertAdjacentHTML('beforeEnd', vel);
    },

    drawRect : function(x, y, width, height, lineColor, fillColor) {
      return this.drawShape([
        [x, y],
        [x, y + height],
        [x + width, y + height],
        [x + width, y],
        [x, y]
      ], lineColor, fillColor);
    }
  });

})(jQuery);