// Chart design based on the recommendations of Stephen Few. Implementation
// based on the work of Clint Ivy, Jamie Love, and Jason Davies.
// http://projects.instantcognition.com/protovis/bulletchart/
nv.models.bullet = function() {
  var orient = 'left', // TODO top & bottom
      reverse = false,
      margin = {top: 0, right: 0, bottom: 0, left: 0},
      ranges = function(d) { return d.ranges },
      markers = function(d) { return d.markers },
      measures = function(d) { return d.measures },
      width = 380,
      height = 30,
      tickFormat = null;

  var dispatch = d3.dispatch('elementMouseover', 'elementMouseout');

  // For each small multiple…
  function chart(g) {
    g.each(function(d, i) {
      var availableWidth = width - margin.left - margin.right,
          availableHeight = height - margin.top - margin.bottom;

      var rangez = ranges.call(this, d, i).slice().sort(d3.descending),
          markerz = markers.call(this, d, i).slice().sort(d3.descending),
          measurez = measures.call(this, d, i).slice().sort(d3.descending);


      var wrap = d3.select(this).selectAll('g.nv-wrap.nv-bullet').data([d]);
      var wrapEnter = wrap.enter().append('g').attr('class', 'nvd3 nv-wrap nv-bullet');
      var gEnter = wrapEnter.append('g');

      var g = wrap.select('g')
      wrap.attr('transform', 'translate(' + margin.left + ',' + margin.top + ')');


      // Compute the new x-scale.
      var x1 = d3.scale.linear()
          .domain([0, Math.max(rangez[0], markerz[0], measurez[0])])  // TODO: need to allow forceX and forceY, and xDomain, yDomain
          .range(reverse ? [availableWidth, 0] : [0, availableWidth]);

      // Retrieve the old x-scale, if this is an update.
      var x0 = this.__chart__ || d3.scale.linear()
          .domain([0, Infinity])
          .range(x1.range());

      // Stash the new scale.
      this.__chart__ = x1;

      /*
      // Derive width-scales from the x-scales.
      var w0 = bulletWidth(x0),
          w1 = bulletWidth(x1);

      function bulletWidth(x) {
        var x0 = x(0);
        return function(d) {
          return Math.abs(x(d) - x(0));
        };
      }

      function bulletTranslate(x) {
        return function(d) {
          return 'translate(' + x(d) + ',0)';
        };
      }
      */

      var w0 = function(d) { return Math.abs(x0(d) - x0(0)) }, // TODO: could optimize by precalculating x0(0) and x1(0)
          w1 = function(d) { return Math.abs(x1(d) - x1(0)) };


      // Update the range rects.
      var range = g.selectAll('rect.nv-range')
          .data(rangez);

      range.enter().append('rect')
          .attr('class', function(d, i) { return 'nv-range nv-s' + i; })
          .attr('width', w0)
          .attr('height', availableHeight)
          .attr('x', reverse ? x0 : 0)
          .on('mouseover', function(d,i) { 
              dispatch.elementMouseover({
                value: d,
                label: (i <= 0) ? 'Maximum' : (i > 1) ? 'Minimum' : 'Mean', //TODO: make these labels a variable
                pos: [x1(d), availableHeight/2]
              })
          })
          .on('mouseout', function(d,i) { 
              dispatch.elementMouseout({
                value: d,
                label: (i <= 0) ? 'Minimum' : (i >=1) ? 'Maximum' : 'Mean', //TODO: make these labels a variable
              })
          })

      d3.transition(range)
          .attr('x', reverse ? x1 : 0)
          .attr('width', w1)
          .attr('height', availableHeight);


      // Update the measure rects.
      var measure = g.selectAll('rect.nv-measure')
          .data(measurez);

      measure.enter().append('rect')
          .attr('class', function(d, i) { return 'nv-measure nv-s' + i; })
          .attr('width', w0)
          .attr('height', availableHeight / 3)
          .attr('x', reverse ? x0 : 0)
          .attr('y', availableHeight / 3)
          .on('mouseover', function(d) { 
              dispatch.elementMouseover({
                value: d,
                label: 'Current', //TODO: make these labels a variable
                pos: [x1(d), availableHeight/2]
              })
          })
          .on('mouseout', function(d) { 
              dispatch.elementMouseout({
                value: d,
                label: 'Current' //TODO: make these labels a variable
              })
          })

      d3.transition(measure)
          .attr('width', w1)
          .attr('height', availableHeight / 3)
          .attr('x', reverse ? x1 : 0)
          .attr('y', availableHeight / 3);



      // Update the marker lines.
      var marker = g.selectAll('path.nv-markerTriangle')
          .data(markerz);

      var h3 =  availableHeight / 6;
      marker.enter().append('path')
          .attr('class', 'nv-markerTriangle')
          .attr('transform', function(d) { return 'translate(' + x0(d) + ',' + (availableHeight / 2) + ')' })
          .attr('d', 'M0,' + h3 + 'L' + h3 + ',' + (-h3) + ' ' + (-h3) + ',' + (-h3) + 'Z')
          .on('mouseover', function(d,i) {
              dispatch.elementMouseover({
                value: d,
                label: 'Previous',
                pos: [x1(d), availableHeight/2]
              })
          })
          .on('mouseout', function(d,i) {
              dispatch.elementMouseout({
                value: d,
                label: 'Previous'
              })
          });

      d3.transition(marker)
          .attr('transform', function(d) { return 'translate(' + x1(d) + ',' + (availableHeight / 2) + ')' });

      marker.exit().remove();


    });
    d3.timer.flush();
  }


  chart.dispatch = dispatch;

  // left, right, top, bottom
  chart.orient = function(_) {
    if (!arguments.length) return orient;
    orient = _;
    reverse = orient == 'right' || orient == 'bottom';
    return chart;
  };

  // ranges (bad, satisfactory, good)
  chart.ranges = function(_) {
    if (!arguments.length) return ranges;
    ranges = _;
    return chart;
  };

  // markers (previous, goal)
  chart.markers = function(_) {
    if (!arguments.length) return markers;
    markers = _;
    return chart;
  };

  // measures (actual, forecast)
  chart.measures = function(_) {
    if (!arguments.length) return measures;
    measures = _;
    return chart;
  };

  chart.width = function(_) {
    if (!arguments.length) return width;
    width = _;
    return chart;
  };

  chart.height = function(_) {
    if (!arguments.length) return height;
    height = _;
    return chart;
  };

  chart.margin = function(_) {
    if (!arguments.length) return margin;
    margin = _;
    return chart;
  };

  chart.tickFormat = function(_) {
    if (!arguments.length) return tickFormat;
    tickFormat = _;
    return chart;
  };

  return chart;
};