// Copyright (c) 2014 Rafael Caricio. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

var GradientParser = (GradientParser || {});

GradientParser.stringify = (function() {

  var visitor = {

    'visit_linear-gradient': function(node) {
      var orientation = visitor.visit(node.orientation);
      if (orientation) {
        orientation += ', ';
      }

      return 'linear-gradient('+ orientation + visitor.visit(node.colorStops) + ')';
    },

    visit_literal: function(node) {
      return node.value;
    },

    visit_angular: function(node) {
      return node.value + 'deg';
    },

    visit_hex: function(node) {
      return '#' + node.value;
    },

    visit_rgb: function(node) {
      return 'rgb(' + node.value.join(', ') + ')';
    },

    visit_rgba: function(node) {
      return 'rgba(' + node.value.join(', ') + ')';
    },

    visit_directional: function(node) {
      return 'to ' + node.value;
    },

    visit_array: function(elements) {
      var result = '',
          size = elements.length;

      elements.forEach(function(element, i) {
        result += visitor.visit(element);
        if (i < size - 1) {
          result += ', ';
        }
      });

      return result;
    },

    visit: function(element) {
      if (!element) {
        return '';
      }

      if (element instanceof Array) {
        return visitor.visit_array(element, result);
      } else if (element.type) {
        var nodeVisitor = visitor['visit_' + element.type];
        if (nodeVisitor) {
          return nodeVisitor(element);
        } else {
          throw Error('Missing visitor visit_' + element.type);
        }
      } else {
        throw Error('Invalid node.');
      }
    }

  };

  return function(root) {
    return visitor.visit(root);
  };
})();