(function() {

  packages = {

    // Lazily construct the package hierarchy from class names.

    root: function(classes) {

      var map = {};

      function find(name, data) {

        var node = map[name], i;

        if (!node) {

          node = map[name] = data || {name: name, children: []};

          if (name.length) {

            node.parent = find(name.substring(0, i = name.lastIndexOf(".")));

            node.parent.children.push(node);

            node.key = name.substring(i + 1);

          }

        }

        return node;

      }

      classes.forEach(function(d) {

        find(d.name, d);

      });

      return map[""];

    },

    // Return a list of imports for the given array of nodes.

    imports: function(nodes) {

      var map = {},

          imports = [];

      // Compute a map from name to node.

      nodes.forEach(function(d) {

        map[d.name] = d;

      });

      // For each import, construct a link from the source to target node.

      nodes.forEach(function(d) {

        if (d.imports) d.imports.forEach(function(i) {

          imports.push({source: map[d.name], target: map[i]});

        });

      });

      return imports;

    }

  };

})();