(function () {

var
  D = Flotr.DOM,
  _ = Flotr._;

Flotr.addPlugin('legend', {
  options: {
    show: true,            // => setting to true will show the legend, hide otherwise
    noColumns: 1,          // => number of colums in legend table // @todo: doesn't work for HtmlText = false
    labelFormatter: function(v){return v;}, // => fn: string -> string
    labelBoxBorderColor: '#CCCCCC', // => border color for the little label boxes
    labelBoxWidth: 14,
    labelBoxHeight: 10,
    labelBoxMargin: 5,
    labelBoxOpacity: 0.4,
    container: null,       // => container (as jQuery object) to put legend in, null means default on top of graph
    position: 'nw',        // => position of default legend container within plot
    margin: 5,             // => distance from grid edge to default legend container within plot
    backgroundColor: null, // => null means auto-detect
    backgroundOpacity: 0.85// => set to 0 to avoid background, set to 1 for a solid background
  },
  callbacks: {
    'flotr:afterinit': function() {
      this.legend.insertLegend();
    }
  },
  /**
   * Adds a legend div to the canvas container or draws it on the canvas.
   */
  insertLegend: function(){

    if(!this.options.legend.show)
      return;

    var series      = this.series,
      plotOffset    = this.plotOffset,
      options       = this.options,
      legend        = options.legend,
      fragments     = [],
      rowStarted    = false, 
      ctx           = this.ctx,
      itemCount     = _.filter(series, function(s) {return (s.label && !s.hide);}).length,
      p             = legend.position, 
      m             = legend.margin,
      i, label, color;

    if (itemCount) {
      if (!options.HtmlText && this.textEnabled && !legend.container) {
        var style = {
          size: options.fontSize*1.1,
          color: options.grid.color
        };

        var lbw = legend.labelBoxWidth,
            lbh = legend.labelBoxHeight,
            lbm = legend.labelBoxMargin,
            offsetX = plotOffset.left + m,
            offsetY = plotOffset.top + m;
        
        // We calculate the labels' max width
        var labelMaxWidth = 0;
        for(i = series.length - 1; i > -1; --i){
          if(!series[i].label || series[i].hide) continue;
          label = legend.labelFormatter(series[i].label);
          labelMaxWidth = Math.max(labelMaxWidth, this._text.measureText(label, style).width);
        }
        
        var legendWidth  = Math.round(lbw + lbm*3 + labelMaxWidth),
            legendHeight = Math.round(itemCount*(lbm+lbh) + lbm);
        
        if(p.charAt(0) == 's') offsetY = plotOffset.top + this.plotHeight - (m + legendHeight);
        if(p.charAt(1) == 'e') offsetX = plotOffset.left + this.plotWidth - (m + legendWidth);
        
        // Legend box
        color = this.processColor(legend.backgroundColor || 'rgb(240,240,240)', {opacity: legend.backgroundOpacity || 0.1});
        
        ctx.fillStyle = color;
        ctx.fillRect(offsetX, offsetY, legendWidth, legendHeight);
        ctx.strokeStyle = legend.labelBoxBorderColor;
        ctx.strokeRect(Flotr.toPixel(offsetX), Flotr.toPixel(offsetY), legendWidth, legendHeight);
        
        // Legend labels
        var x = offsetX + lbm;
        var y = offsetY + lbm;
        for(i = 0; i < series.length; i++){
          if(!series[i].label || series[i].hide) continue;
          label = legend.labelFormatter(series[i].label);
          
          ctx.fillStyle = series[i].color;
          ctx.fillRect(x, y, lbw-1, lbh-1);
          
          ctx.strokeStyle = legend.labelBoxBorderColor;
          ctx.lineWidth = 1;
          ctx.strokeRect(Math.ceil(x)-1.5, Math.ceil(y)-1.5, lbw+2, lbh+2);
          
          // Legend text
          Flotr.drawText(ctx, label, x + lbw + lbm, y + lbh, style);
          
          y += lbh + lbm;
        }
      }
      else {
        for(i = 0; i < series.length; ++i){
          if(!series[i].label || series[i].hide) continue;
          
          if(i % legend.noColumns === 0){
            fragments.push(rowStarted ? '</tr><tr>' : '<tr>');
            rowStarted = true;
          }
           
          // @TODO remove requirement on bars
          var s = series[i],
            boxWidth = legend.labelBoxWidth,
            boxHeight = legend.labelBoxHeight,
            opacityValue = (s.bars ? s.bars.fillOpacity : legend.labelBoxOpacity),
            opacity = 'opacity:' + opacityValue + ';filter:alpha(opacity=' + opacityValue*100 + ');';

          label = legend.labelFormatter(s.label);
          color = 'background-color:' + ((s.bars && s.bars.show && s.bars.fillColor && s.bars.fill) ? s.bars.fillColor : s.color) + ';';
          
          fragments.push(
            '<td class="flotr-legend-color-box">',
              '<div style="border:1px solid ', legend.labelBoxBorderColor, ';padding:1px">',
                '<div style="width:', (boxWidth-1), 'px;height:', (boxHeight-1), 'px;border:1px solid ', series[i].color, '">', // Border
                  '<div style="width:', boxWidth, 'px;height:', boxHeight, 'px;', 'opacity:.4;', color, '"></div>', // Background
                '</div>',
              '</div>',
            '</td>',
            '<td class="flotr-legend-label">', label, '</td>'
          );
        }
        if(rowStarted) fragments.push('</tr>');
          
        if(fragments.length > 0){
          var table = '<table style="font-size:smaller;color:' + options.grid.color + '">' + fragments.join('') + '</table>';
          if(legend.container){
            D.insert(legend.container, table);
          }
          else {
            var styles = {position: 'absolute', 'z-index': 2};
            
                 if(p.charAt(0) == 'n') { styles.top = (m + plotOffset.top) + 'px'; styles.bottom = 'auto'; }
            else if(p.charAt(0) == 's') { styles.bottom = (m + plotOffset.bottom) + 'px'; styles.top = 'auto'; }
                 if(p.charAt(1) == 'e') { styles.right = (m + plotOffset.right) + 'px'; styles.left = 'auto'; }
            else if(p.charAt(1) == 'w') { styles.left = (m + plotOffset.left) + 'px'; styles.right = 'auto'; }
                 
            var div = D.create('div'), size;
            div.className = 'flotr-legend';
            D.setStyles(div, styles);
            D.insert(div, table);
            D.insert(this.el, div);
            
            if(!legend.backgroundOpacity)
              return;

            var c = legend.backgroundColor || options.grid.backgroundColor || '#ffffff';

            _.extend(styles, D.size(div), {
              'backgroundColor': c,
              'z-index': 1
            });
            styles.width += 'px';
            styles.height += 'px';

             // Put in the transparent background separately to avoid blended labels and
            div = D.create('div');
            div.className = 'flotr-legend-bg';
            D.setStyles(div, styles);
            D.opacity(div, legend.backgroundOpacity);
            D.insert(div, ' ');
            D.insert(this.el, div);
          }
        }
      }
    }
  }
});
})();