var util = require('../util');
var XmlNode = require('./xml-node').XmlNode;
var XmlText = require('./xml-text').XmlText;

function XmlBuilder() { }

XmlBuilder.prototype.toXML = function(params, shape, rootElement, noEmpty) {
  var xml = new XmlNode(rootElement);
  applyNamespaces(xml, shape, true);
  serialize(xml, params, shape);
  return xml.children.length > 0 || noEmpty ? xml.toString() : '';
};

function serialize(xml, value, shape) {
  switch (shape.type) {
    case 'structure': return serializeStructure(xml, value, shape);
    case 'map': return serializeMap(xml, value, shape);
    case 'list': return serializeList(xml, value, shape);
    default: return serializeScalar(xml, value, shape);
  }
}

function serializeStructure(xml, params, shape) {
  util.arrayEach(shape.memberNames, function(memberName) {
    var memberShape = shape.members[memberName];
    if (memberShape.location !== 'body') return;

    var value = params[memberName];
    var name = memberShape.name;
    if (value !== undefined && value !== null) {
      if (memberShape.isXmlAttribute) {
        xml.addAttribute(name, value);
      } else if (memberShape.flattened) {
        serialize(xml, value, memberShape);
      } else {
        var element = new XmlNode(name);
        xml.addChildNode(element);
        applyNamespaces(element, memberShape);
        serialize(element, value, memberShape);
      }
    }
  });
}

function serializeMap(xml, map, shape) {
  var xmlKey = shape.key.name || 'key';
  var xmlValue = shape.value.name || 'value';

  util.each(map, function(key, value) {
    var entry = new XmlNode(shape.flattened ? shape.name : 'entry');
    xml.addChildNode(entry);

    var entryKey = new XmlNode(xmlKey);
    var entryValue = new XmlNode(xmlValue);
    entry.addChildNode(entryKey);
    entry.addChildNode(entryValue);

    serialize(entryKey, key, shape.key);
    serialize(entryValue, value, shape.value);
  });
}

function serializeList(xml, list, shape) {
  if (shape.flattened) {
    util.arrayEach(list, function(value) {
      var name = shape.member.name || shape.name;
      var element = new XmlNode(name);
      xml.addChildNode(element);
      serialize(element, value, shape.member);
    });
  } else {
    util.arrayEach(list, function(value) {
      var name = shape.member.name || 'member';
      var element = new XmlNode(name);
      xml.addChildNode(element);
      serialize(element, value, shape.member);
    });
  }
}

function serializeScalar(xml, value, shape) {
  xml.addChildNode(
    new XmlText(shape.toWireFormat(value))
  );
}

function applyNamespaces(xml, shape, isRoot) {
  var uri, prefix = 'xmlns';
  if (shape.xmlNamespaceUri) {
    uri = shape.xmlNamespaceUri;
    if (shape.xmlNamespacePrefix) prefix += ':' + shape.xmlNamespacePrefix;
  } else if (isRoot && shape.api.xmlNamespaceUri) {
    uri = shape.api.xmlNamespaceUri;
  }

  if (uri) xml.addAttribute(prefix, uri);
}

/**
 * @api private
 */
module.exports = XmlBuilder;