// 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,
      duration = 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 bullet(g) {
    g.each(function(d, i) {
      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),
          g = d3.select(this);

      // 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 ? [width, 0] : [0, width]);

      // 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.range")
          .data(rangez);

      range.enter().append("rect")
          .attr("class", function(d, i) { return "range s" + i; })
          .attr("width", w0)
          .attr("height", height)
          .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), height/2]
              })
          })
          .on('mouseout', function(d,i) { 
              dispatch.elementMouseout({
                value: d,
                label: (i <= 0) ? 'Minimum' : (i >=1) ? 'Maximum' : 'Mean', //TODO: make these labels a variable
              })
          })
        .transition()
          .duration(duration)
          .attr("width", w1)
          .attr("x", reverse ? x1 : 0);

      range.transition()
          .duration(duration)
          .attr("x", reverse ? x1 : 0)
          .attr("width", w1)
          .attr("height", height);


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

      measure.enter().append("rect")
          .attr("class", function(d, i) { return "measure s" + i; })
          .attr("width", w0)
          .attr("height", height / 3)
          .attr("x", reverse ? x0 : 0)
          .attr("y", height / 3)
          .on('mouseover', function(d) { 
              dispatch.elementMouseover({
                value: d,
                label: 'Current', //TODO: make these labels a variable
                pos: [x1(d), height/2]
              })
          })
          .on('mouseout', function(d) { 
              dispatch.elementMouseout({
                value: d,
                label: 'Current' //TODO: make these labels a variable
              })
          })
        .transition()
          .duration(duration)
          .attr("width", w1)
          .attr("x", reverse ? x1 : 0)

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



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

      var h3 =  height / 6;
      marker.enter().append("path")
          .attr("class", "markerTriangle")
          .attr('transform', function(d) { return 'translate(' + x0(d) + ',' + (height / 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), height/2]
              })
          })
          .on('mouseout', function(d,i) { 
              dispatch.elementMouseout({
                value: d,
                label: 'Previous'
              })
          });

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

      marker.exit().remove();


/*
      marker.enter().append("line")
          .attr("class", "marker")
          .attr("x1", x0)
          .attr("x2", x0)
          .attr("y1", height / 6)
          .attr("y2", height * 5 / 6)
        .transition()
          .duration(duration)
          .attr("x1", x1)
          .attr("x2", x1);


      marker.transition(
          .duration(duration)
          .attr("x1", x1)
          .attr("x2", x1)
          .attr("y1", height / 6)
          .attr("y2", height * 5 / 6);
         */

      // Compute the tick format.
      var format = tickFormat || x1.tickFormat(8);

      // Update the tick groups.
      var tick = g.selectAll("g.tick")
          .data(x1.ticks(8), function(d) {
            return this.textContent || format(d);
          });

      // Initialize the ticks with the old scale, x0.
      var tickEnter = tick.enter().append("g")
          .attr("class", "tick")
          .attr("transform", function(d) { return "translate(" + x0(d) + ",0)" })
          .style("opacity", 1e-6);

      tickEnter.append("line")
          .attr("y1", height)
          .attr("y2", height * 7 / 6);

      tickEnter.append("text")
          .attr("text-anchor", "middle")
          .attr("dy", "1em")
          .attr("y", height * 7 / 6)
          .text(format);

      // Transition the entering ticks to the new scale, x1.
      tickEnter.transition()
          .duration(duration)
          .attr("transform", function(d) { return "translate(" + x1(d) + ",0)" })
          .style("opacity", 1);

      // Transition the updating ticks to the new scale, x1.
      var tickUpdate = tick.transition()
          .duration(duration)
          .attr("transform", function(d) { return "translate(" + x1(d) + ",0)" })
          .style("opacity", 1);

      tickUpdate.select("line")
          .attr("y1", height)
          .attr("y2", height * 7 / 6);

      tickUpdate.select("text")
          .attr("y", height * 7 / 6);

      // Transition the exiting ticks to the new scale, x1.
      tick.exit().transition()
          .duration(duration)
          .attr("transform", function(d) { return "translate(" + x1(d) + ",0)" })
          .style("opacity", 1e-6)
          .remove();
    });
    d3.timer.flush();
  }


  bullet.dispatch = dispatch;

  // left, right, top, bottom
  bullet.orient = function(x) {
    if (!arguments.length) return orient;
    orient = x;
    reverse = orient == "right" || orient == "bottom";
    return bullet;
  };

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

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

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

  bullet.width = function(x) {
    if (!arguments.length) return width;
    width = x;
    return bullet;
  };

  bullet.height = function(x) {
    if (!arguments.length) return height;
    height = x;
    return bullet;
  };

  bullet.tickFormat = function(x) {
    if (!arguments.length) return tickFormat;
    tickFormat = x;
    return bullet;
  };

  bullet.duration = function(x) {
    if (!arguments.length) return duration;
    duration = x;
    return bullet;
  };

  return bullet;
};