/**
 * @license
 * Copyright (c) 2015 The Polymer Project Authors. All rights reserved.
 * This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
 * The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
 * The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
 * Code distributed by Google as part of the polymer project is also
 * subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 */
// jshint node: true
'use strict';
var dom5 = require('dom5');

var p = dom5.predicates;

var isHtmlImportNode = p.AND(
  p.hasTagName('link'),
  p.hasAttrValue('rel', 'import'),
  p.NOT(
    p.hasAttrValue('type', 'css')
  )
);

var isStyleNode = p.OR(
  // inline style
  p.hasTagName('style'),
  // external stylesheet
  p.AND(
    p.hasTagName('link'),
    p.hasAttrValue('rel', 'stylesheet')
  ),
  // polymer specific external stylesheet
  p.AND(
    p.hasTagName('link'),
    p.hasAttrValue('rel', 'import'),
    p.hasAttrValue('type', 'css')
  )
);

var isJSScriptNode = p.AND(
  p.hasTagName('script'),
  p.OR(
    p.NOT(p.hasAttr('type')),
    p.hasAttrValue('type', 'text/javascript'),
    p.hasAttrValue('type', 'application/javascript')
  )
);

function addNode(node, registry) {
  if (isHtmlImportNode(node)) {
    registry.import.push(node);
  } else if (isStyleNode(node)) {
    registry.style.push(node);
  } else if (isJSScriptNode(node)) {
    registry.script.push(node);
  } else if (node.tagName === 'base') {
    registry.base.push(node);
  } else if (node.tagName === 'template') {
    registry.template.push(node);
  } else if (node.tagName === 'dom-module') {
    registry['dom-module'].push(node);
  } else if (dom5.isCommentNode(node)) {
    registry.comment.push(node);
  }
}

function getLineAndColumn(string, charNumber) {
  if (charNumber > string.length) {
    return undefined;
  }
  // TODO(ajo): Caching the line lengths of each document could be much faster.
  var sliced = string.slice(0,charNumber+1);
  var split = sliced.split('\n');
  var line = split.length;
  var column = split[split.length - 1].length;
  return {line: line, column: column};
}

/**
* Parse5's representation of a parsed html document.
* @typedef {Object} DocumentAST
*/

/**
* The ASTs of the HTML elements needed to represent Polymer elements.
* @typedef {Object} ParsedImport
* @property {Array<DocumentAST>} template The entry points to the AST at each outermost template tag.
* @property {Array<DocumentAST>} script The entry points to the AST at each script tag not inside a template.
* @property {Array<DocumentAST>} style The entry points to the AST at style tag outside a template.
* @property {Array<DocumentAST>} dom-module The entry points to the AST at each outermost dom-module element.
* @property {DocumentAST} ast The full parse5 ast for the document.
*/

/**
* Parse html into ASTs.
* @param {string} htmlString A utf8, html5 document containing polymer element or module definitons.
* @param {string} href       The path of the document.
* @return {ParsedImport}
*/
var importParse = function importParse(htmlString, href) {
  var doc;
  try {
    doc = dom5.parse(htmlString, {locationInfo: true});
  } catch (err) {
    console.log(err);
    return null;
  }

  // Add line/column information
  dom5.treeMap(doc, function(node) {
    if (node.__location && node.__location.start >= 0) {
      node.__locationDetail = getLineAndColumn(htmlString, node.__location.start);
      if (href) {
        node.__ownerDocument = href;
      }
    }
  });

  var registry = {
      base: [],
      template: [],
      script: [],
      style: [],
      import: [],
      'dom-module': [],
      comment: []};

  var queue = [].concat(doc.childNodes);
  var nextNode;
  while (queue.length > 0) {
    nextNode = queue.shift();
    if (nextNode) {
      queue = queue.concat(nextNode.childNodes);
      addNode(nextNode, registry);
    }
  }
  registry.ast = doc;
  return registry;
};

module.exports = importParse;