//-------------------------------------------------------------------//
//                                                                   //
//                          MAKE TOOLTIP                             //
//                                                                   //
//-------------------------------------------------------------------//
function make_tooltip(obj, text_array, chart_group, canvas, margins) {
  // get the x and y coordinates of the object to apply tooltip too
  var x = obj.node().transform.baseVal.consolidate().matrix.e
  var y = obj.node().transform.baseVal.consolidate().matrix.f

  // for convenience
  var tooltip_config = charts_config.plot_attributes.tooltip
  var sep = tooltip_config.default_seperation_from_object

  // Add the tooltip to the chart and as a child - the text group
  var tooltip = chart_group.append("g").attr("class", "tooltip_group")
  var text_group = tooltip.append("g").attr("class", "tooltip_text_group")

  // Add text in reverse order placing low to high
  text_array.reverse()
  for (var i = 0; i < text_array.length; i++) {
    var text = text_group.append("text")
                        .text(text_array[i])
                        .attr("font-size", tooltip_config.size)
                        .attr("text-anchor", "middle")
                        .attr("x", x)
                        .attr("y", y - sep - tooltip_config.curve - (i * tooltip_config.size))
                        .attr("class", "tooltipText")
                        .attr("fill", tooltip_config.emphasis)
                        .attr("font-family", tooltip_config.family)
                        .attr("font-weight", "normal")

    // The first line in the tooltip gets different coloration
    if (i < text_array.length - 1) {
        text.attr("fill", tooltip_config.text)
            .attr("font-family", tooltip_config.family)
            .attr("font-weight", "normal")
    }
  }

  // Make the bubble around the text
  var bubble = tooltip.append("path")
                      .attr("d", make_tooltip_bubble(text_group))
                      .attr("fill", tooltip_config.fill)
                      .attr("stroke", tooltip_config.stroke)
                      .attr("opacity", tooltip_config.opacity)

  // Text goes in front of the box
  text_group.raise()

  // Get the bounding box of the bubble
  var bubble_box = bubble.node().getBBox()

  // Calculate the limits to contain the tooltip
  var limits = {
    "top": margins.y.top + margins.buttons + margins.title,
    "bottom": canvas.y - margins.axes.x - margins.y.bottom,
    "left": margins.x.left + margins.axes.y,
    "right": canvas.x - margins.x.right
  }

  // Get the boundaries of the object
  var object_boundaries = {
    "left": x,
    "right": x + obj.node().getBBox().width,
    "top": y,
    "bottom": y + obj.node().getBBox().height
  }

  // Calculate putative tooltip placements
  var tooltip_placements = {
    "upper_left": {"x": object_boundaries.left - bubble_box.width - sep, "y":object_boundaries.top - bubble_box.height - sep},
    "upper_right": {"x":object_boundaries.right + sep, "y": object_boundaries.top - bubble_box.height - sep},
    "lower_left": {"x":object_boundaries.left - bubble_box.width - sep, "y": object_boundaries.bottom + sep},
    "lower_right": {"x":object_boundaries.right + sep, "y":object_boundaries.bottom + sep}
  }

  // Figure out which placements fall within the limits
  var valid_placments = {
    "upper_left": {"x": tooltip_placements.upper_left.x > limits.left, "y":  tooltip_placements.upper_left.y > limits.top},
    "upper_right": {"x": tooltip_placements.upper_right.x + bubble_box.width < limits.right, "y": tooltip_placements.upper_right.y > limits.top},
    "lower_left": {"x": tooltip_placements.lower_left.x > limits.left, "y": tooltip_placements.lower_left.y + bubble_box.height < limits.bottom},
    "lower_right": {"x": tooltip_placements.lower_right.x + bubble_box.width < limits.right, "y": tooltip_placements.lower_right.y + bubble_box.height < limits.bottom}
  }

  var placements = keys(valid_placments)
  var tooltip_placement
  for (var i = 0; i < placements.length; i++) {
    var current_placement = valid_placments[placements[i]]
    if (current_placement.x && current_placement.y) {
      tooltip_placement = tooltip_placements[placements[i]]
      break
    }
  }

  // Reposition the tooltip to its correct location
  tooltip.attr("transform", "translate("+(tooltip_placement.x - bubble_box.x)+","+(tooltip_placement.y - bubble_box.y)+")")
}

function transform_values(selection) {
  return {
    "x": selection.node().transform.baseVal.consolidate().matrix.e,
    "y": selection.node().transform.baseVal.consolidate().matrix.f
  }
}

function make_tooltip_bubble(text_group) {
  var textBox = text_group.node().getBBox()
  var x = textBox.x
  var y = textBox.y
  var width = textBox.width
  var height = textBox.height

  var point = charts_config.plot_attributes.tooltip.point
  var curve = charts_config.plot_attributes.tooltip.curve

  // Start at bottom center and work around left - up - right - down - close
  d = "M " + (x + width / 2) + " " + (y + height + curve)
  // go left
  d += "l -" + (width / 2) + " 0 "
  // curve left and up
  d += "q -" + curve + " 0 -" + curve + " -" + curve + " "
  // go up
  d += "l 0 -" + (height) + " "
  // curve up and right
  d += "q 0 -" + curve + " " + curve + " -" + curve + " "
  // go right
  d += "l " + (width) + " 0 "
  // curve right and down
  d += "q " + curve + " 0 " + curve + " " + curve + " "
  // go down
  d += "l 0 " + (height) + " "
  //  curve down and left
  d += "q 0 " + curve + " -" + curve + " " + curve + " "
  // go left
  d += "l -" + (width / 2) + " 0 "
  // close
  d += " z"
  return d
}