$(function() {
  var data = #{json};
  var parmalink = costCentreParmalink();
  var chart = costCentreChart({
    data: data,
    parmalink: parmalink
  });
  var button = profilingModeButton({
    chart: chart,
    parmalink: parmalink
  });

  chart.transposeById(parmalink.id());
  $(window).bind('popstate', function(event) {
    if (!window.history.ready && !event.originalEvent.state) {
      return; // workaround for popstate on load
    }
    parmalink.popstate(location.pathname);
    button.mode(parmalink.mode());
    chart.mode(parmalink.mode());
    chart.transposeById(parmalink.id());
  });
});

function costCentreParmalink(spec) {
  var that = {};
  var parsed = parse(location.pathname),
      prefix = parsed[1],
      mode   = parsed[2],
      suffix = parsed[3];

  function pathname() {
    return prefix + mode + suffix;
  };

  function parse(path) {
    var regex = /^(\/reports\/[0-9]+\/)(time|alloc)(.*)$/;
    return regex.exec(path);
  }

  that.mode = function(newMode) {
    if (!newMode)
      return mode; // getter

    mode = newMode;
    window.history.ready = true; // workaround for popstate on load
    history.pushState(null, null, pathname()); // HTML 5 History API
    return mode;
  };

  that.transpose = function(node) {
    var cursor = node, path = [];
    for (cursor = node; cursor.parent; cursor = cursor.parent) {
      path.unshift(cursor.no);
    }
    if (path.length > 0) {
      suffix = "/" + path.join("/");
    } else {
      suffix = "";
    }
  };

  that.popstate = function(url) {
    var parsed = parse(url);
    mode   = parsed[2];
    suffix = parsed[3];
  };

  that.id = function() {
    var regex = /^.*\/([0-9]*)$/;
    var matched = regex.exec(suffix);
    return matched ? matched[1] : null;
  };

  that.pathname = pathname;

  return that;
}

function profilingModeButton(spec) {
  var that = {};
  var chart = spec.chart, parmalink = spec.parmalink;
  var timeButton  = $("#time"),
      allocButton = $("#alloc"),
      _mode;

  // methods
  var mode = function(newMode) {
    if (!newMode)
      return _mode; // getter

    _mode = newMode;
    // buttons
    if (_mode == "time") {
      timeButton.addClass("active");
      allocButton.removeClass("active");
    } else {
      timeButton.removeClass("active");
      allocButton.addClass("active");
    }
    // chart
    chart.mode(_mode);
    return _mode;
  };

  // setup initial states and event handlers
  mode(parmalink.mode());
  timeButton.click(function(event) {
    parmalink.mode("time");
    mode(parmalink.mode());
  });
  allocButton.click(function(event) {
    parmalink.mode("alloc");
    mode(parmalink.mode());
  });

  // public slots
  that.mode = mode;

  return that;
}

function costCentreChart(spec) {
  var that = {};

  var cursor = spec.data,
      selector = spec.selector,
      parmalink = spec.parmalink;
  var context = costCentreContext({cursor: cursor});

  // chart
  var chart = $("#chart"),
      w = spec.w || chart.width(),
      h = spec.h || chart.height(),
      r = Math.min(w, h) / 2,
      x = d3.scale.linear().range([0, 2*Math.PI]),
      y = d3.scale.sqrt().range([0, r]),
      color = spec.color || d3.scale.category20c();

  var vis = d3.select("#chart")
    .append("svg:svg")
    .attr("width", w)
    .attr("height", h)
    .append("svg:g")
    .attr("transform", "translate(" + w/2 + "," + h/2 + ")");

  var partition = d3.layout.partition()
    .children(function(d) { return d.subForest; })
    .value(value(parmalink.mode()));

  var arc = d3.svg.arc()
    .startAngle(function(d) { return Math.max(0, Math.min(2*Math.PI, x(d.x))); })
    .endAngle(function(d) { return Math.max(0, Math.min(2*Math.PI, x(d.x + d.dx))); })
    .innerRadius(function(d) { return Math.max(0, y(d.y)); })
    .outerRadius(function(d) { return Math.max(0, y(d.y + d.dy)); });

  var path = vis.data([cursor]).selectAll("path")
    .data(partition.nodes)
    .enter().append("svg:path")
    .attr("d", arc)
    .attr("id", function(d) { return "cc" + d.no + (d.isParent ? "p" : ""); })
    .style("fill", function(d) { return color((d.children ? d : d.parent).name); })
    .on("click", click)
    .on("mouseover", mouseover)
    .each(function(d) { d.x0 = d.x; d.dx0 = d.dx; }); // stash the old values for transition

  // event handlers
  function click(d) {
    transpose(d);
    parmalink.transpose(d);
    window.history.ready = true; // workaround for popstate on load
    history.pushState(null, null, parmalink.pathname()); // HTML 5 History API
  }

  function mouseover(d) {
    // XXX
  }

  // tweeners
  function arcTween(a) {
    var i = d3.interpolate({x: a.x0, dx: a.dx0}, a);
    return function(t) {
      var b = i(t);
      a.x0  = b.x;
      a.dx0 = b.dx;
      return arc(b);
    };
  }

  function zoomTween(d) {
    var xd = d3.interpolate(x.domain(), [d.x, d.x + d.dx]),
        yd = d3.interpolate(y.domain(), [d.y, 1]),
        yr = d3.interpolate(y.range(), [d.y ? 20 : 0, r]);
    return function(d, i) {
      return i
        ? function(t) { return arc(d); }
        : function(t) { x.domain(xd(t)); y.domain(yd(t)).range(yr(t)); return arc(d); };
    };
  }

  // helper functions
  function value(mode) {
    if (mode === "time")
      return function(d) { return d.individualTime; };
    else
      return function(d) { return d.individualAlloc; };
  }

  function nodeFromId(id) {
    if (!id)
      return null;
    var elem = d3.select("#cc" + id);
    return elem.node().__data__; // XXX: __data__ is not a public API
  }

  var mode = function(mode) {
    path.data(partition.value(value(mode)))
      .transition()
      .duration(500)
      .attrTween("d", arcTween);
  };

  var transpose = function(node) {
    cursor = node;
    context.transpose(cursor);
    path.transition()
      .duration(500)
      .attrTween("d", zoomTween(node));
  };

  var transposeById = function(id) {
    transpose(nodeFromId(id) || spec.data);
  };

  // public slots
  that.mode = mode;
  that.transpose = transpose;
  that.transposeById = transposeById;

  // setup initial states
  mode(parmalink.mode());
  transposeById(parmalink.id());

  return that;
}

function costCentreContext(spec) {
  var that = {};
  var cursor = spec.cursor;

  var showCostCentre = function(node) {
    var currentNode = $("#current-node dl");
    $("#current-node-module",    currentNode).text(node.module);
    $("#current-node-name",      currentNode).text(node.name);
    $("#current-node-number",    currentNode).text(node.no);
    $("#current-node-entries",   currentNode).text(node.entries);
    $("#current-node-ind-time",  currentNode).text(node.individualTime);
    $("#current-node-ind-alloc", currentNode).text(node.individualAlloc);
    $("#current-node-inh-time",  currentNode).text(node.inheritedTime);
    $("#current-node-inh-alloc", currentNode).text(node.inheritedAlloc);
  };

  var showChildren = function(node) {
    $("#children ol li").remove();
    var children = $("#children ol");
    var cs = node.children;
    if (cs) {
      var n = cs.length < 10 ? cs.length : 10;
      for (var i = 0; i < n; i++) {
        children.append("<li>" + cs[i].name + "</li>");
      }
    }
  };

  // setup
  showCostCentre(cursor);
  showChildren(cursor);

  // public slots
  that.transpose = function(node) {
    cursor = node;
    showCostCentre(cursor);
    showChildren(cursor);
  };

  return that;
}