SGH / COMPONENTS

<!--
@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
-->
<link rel="import" href="../polymer/polymer.html">
<link rel="import" href="../hydrolysis/hydrolysis-analyzer.html">
<link rel="import" href="../iron-doc-viewer/iron-doc-viewer.html">
<link rel="import" href="../iron-icons/iron-icons.html">
<link rel="import" href="../iron-ajax/iron-ajax.html">
<link rel="import" href="../iron-selector/iron-selector.html">
<link rel="import" href="../paper-header-panel/paper-header-panel.html">
<link rel="import" href="../paper-toolbar/paper-toolbar.html">
<link rel="import" href="../paper-styles/paper-styles.html">

<!--
Loads Polymer element and behavior documentation using
[Hydrolysis](https://github.com/PolymerLabs/hydrolysis) and renders a complete
documentation page including demos (if available).
-->
<dom-module id="iron-component-page">
  <link rel="import" type="css" href="iron-component-page.css">
  <template>
    <hydrolysis-analyzer id="analyzer" src="[[_srcUrl]]" transitive="[[transitive]]" clean analyzer="{{_hydroDesc}}" loading="{{_hydroLoading}}"></hydrolysis-analyzer>
    <iron-ajax id="ajax" url="[[docSrc]]" handle-as="json" on-response="_handleAjaxResponse"></iron-ajax>

    <paper-header-panel id="headerPanel" mode="waterfall">
      <paper-toolbar catalog-hidden>
        <div class="flex">
          <!-- TODO: Replace with paper-dropdown-menu when available -->
          <select id="active" value="{{active::change}}">
            <template is="dom-repeat" items="[[docElements]]">
              <option value="[[item.is]]">[[item.is]]</option>
            </template>
            <template is="dom-repeat" items="[[docBehaviors]]">
              <option value="[[item.is]]">[[item.is]]</option>
            </template>
          </select>
        </div>
        <iron-selector attr-for-selected="view" selected="{{view}}" id="links" hidden$="[[!docDemos.length]]">
          <a view="docs"><iron-icon icon="description"></iron-icon> Docs</a>
          <a view="[[_demoView(docDemos.0.path)]]"><iron-icon icon="visibility"></iron-icon> <span>Demo</span></a>
        </iron-selector>
      </paper-toolbar>
      <div id="content">
        <iron-selector id="view" selected="[[_viewType(view)]]" attr-for-selected="id">
          <div id="docs">
            <div id="catalog-heading" catalog-only>
              <h2><span>[[active]]</span> <span class="version" hidden$="[[!version]]">[[version]]</span></h2>
            </div>
            <iron-doc-viewer descriptor="{{_activeDescriptor}}"
              on-iron-doc-viewer-component-selected="_handleComponentSelectedEvent"></iron-doc-viewer>
            <div id="nodocs" hidden$="[[_activeDescriptor]]" class="layout fit horizontal center-center">
              No documentation found.
            </div>
          </div>
          <div id="demo"></div>
        </iron-selector>
      </div>
    </paper-header-panel>
  </template>
</dom-module>

<script>
(function() {
  // var hydrolysis = require('hydrolysis');

  /**
   * @param {string} url
   * @return {string} `url` stripped of a file name, if one is present. This
   *     considers URLs like "example.com/foo" to already be a base (no `.` is)
   *     present in the final path part).
   */
  function _baseUrl(url) {
    return url.match(/^(.*?)\/?([^\/]+\.[^\/]+)?$/)[1] + '/';
  }

  Polymer({
    is: 'iron-component-page',
    enableCustomStyleProperties: true,
    properties: {
      /**
       * The URL to an import that declares (or transitively imports) the
       * elements that you wish to see documented.
       *
       * If the URL is relative, it will be resolved relative to the master
       * document.
       *
       * If a `src` URL is not specified, it will resolve the name of the
       * directory containing this element, followed by `dirname.html`. For
       * example:
       *
       * `awesome-sauce/index.html`:
       *
       *     <iron-doc-viewer></iron-doc-viewer>
       *
       * Would implicitly have `src="awesome-sauce.html"`.
       */
      src: {
        type:     String,
        observer: '_srcChanged',
      },

      /**
       * The URL to a precompiled JSON descriptor. If you have precompiled
       * and stored a documentation set using Hydrolysis, you can load the
       * analyzer directly via AJAX by specifying this attribute.
       *
       * If a `doc-src` is not specified, it is ignored and the default
       * rules according to the `src` attribute are used.
       */
      docSrc: {
        type: String,
        observer: '_srcChanged',
      },

      /**
       * The relative root for determining paths to demos and default source
       * detection.
       */
      base: {
        type: String,
        value: function() {
          return this.ownerDocument.baseURI;
        }
      },

      /**
       * The element or behavior that will be displayed on the page. Defaults
       * to the element matching the name of the source file.
       */
      active: {
        type: String,
        notify: true,
        value: ''
      },

      /**
       * The current view. Can be `docs` or `demo`.
       */
      view: {
        type: String,
        value: 'docs',
        notify: true
      },

      /**
       * Whether _all_ dependencies should be loaded and documented.
       *
       * Turning this on will probably slow down the load process dramatically.
       */
      transitive: {
        type: Boolean,
        value: false
      },

      /** The Hydrolysis element descriptors that have been loaded. */
      docElements: {
        type:     Array,
        notify: true,
        readOnly: true,
        value: function() {
          return [];
        }
      },

      /** The Hydrolysis behavior descriptors that have been loaded. */
      docBehaviors: {
        type:     Array,
        notify: true,
        readOnly: true,
        value: function() {
          return [];
        }
      },

      /**
       * Demos for the currently selected element.
       */
      docDemos: {
        type: Array,
        notify: true,
        readOnly: true
      },

      /**
       * The currently displayed element.
       *
       * @type {!hydrolysis.ElementDescriptor}
       */
      _activeDescriptor: Object,

      /**
       * Toggle flag to be used when this element is being displayed in the
       * Polymer Elements catalog.
       */
      _catalog: {
        type: Boolean,
        value: false,
        reflectToAttribute: true
      },
      /**
       * An optional version string.
       */
      version: String,

      /**
       * The hydrolysis analyzer.
       *
       * @type {!hydrolysis.Analyzer}
       */
      _analyzer: {
        type: Object,
        observer: '_analyzerChanged',
      },
      _hydroDesc: {
        type: Object,
        observer: '_detectAnalyzer'
      },
      _ajaxDesc: {
        type: Object,
        observer: '_detectAnalyzer'
      },

      /** Whether the analyzer is loading source. */
      _loading: {
        type:     Boolean,
        observer: '_loadingChanged',
      },
      _hydroLoading: {
        type: Boolean,
        observer: '_detectLoading'
      },
      _ajaxLoading: {
        type: Boolean,
        observer: '_detectLoading'
      },

      /** The complete URL to this component's demo. */
      _demoUrl: {
        type: String,
        value: '',
      },

      /** The complete URL to this component's source. */
      _srcUrl: String,
    },

    observers: [
      '_updateFrameSrc(view, base)',
      '_activeChanged(active, _analyzer)'
    ],

    ready: function() {
      var elements = this._loadJson();
      if (elements) {
        this.docElements = elements;
        this._loading  = false;
      } else {
        // Make sure our change handlers trigger in all cases.
        if (!this.src && !this._catalog) {
          this._srcChanged();
        }
      }
    },

    /**
     * Loads an array of hydrolysis element descriptors (as JSON) from the text
     * content of this element, if present.
     *
     * @return {Array<hydrolysis.ElementDescriptor>} The descriptors, or `null`.
     */
    _loadJson: function() {
      var textContent = '';
      Array.prototype.forEach.call(Polymer.dom(this).childNodes, function(node) {
        textContent = textContent + node.textContent;
      });
      textContent = textContent.trim();
      if (textContent === '') return null;

      try {
        var json = JSON.parse(textContent);
        if (!Array.isArray(json)) return [];
        return json;
      } catch(error) {
        console.error('Failure when parsing JSON:', textContent, error);
        throw error;
      }
    },

    _srcChanged: function() {
      var srcUrl;
      if (this.docSrc) {
        if (!this.$.ajax.lastRequest || (this.docSrc !== this.$.ajax.lastRequest.url && this.docSrc !== this._lastDocSrc)) {
          this._ajaxLoading = true;
          this._ajaxDesc = null;
          this._activeDescriptor = null;
          this.$.ajax.generateRequest();
        }
        this._lastDocSrc = this.docSrc;
        return;
      } else if (this.src) {
        srcUrl = new URL(this.src, this.base).toString();
      } else {
        var base = _baseUrl(this.base);
        srcUrl = new URL(base.match(/([^\/]*)\/$/)[1] + ".html", base).toString();
      }

      // Rewrite gh-pages URLs to https://rawgit.com/
      var match = srcUrl.match(/([^\/\.]+)\.github\.io\/([^\/]+)\/?([^\/]*)$/);
      if (match) {
        srcUrl = "https://cdn.rawgit.com/" + match[1] + "/" + match[2] + "/master/" + match[3];
      }

      this._baseUrl = _baseUrl(srcUrl);
      this._srcUrl  = srcUrl;
      if (!this._hydroLoading) this.$.analyzer.analyze();
    },

    _updateFrameSrc: function(view) {
      if (!view || view.indexOf("demo:") !== 0) return "about:blank";

      var src = view.split(':')[1];
      var demoSrc = new URL(src, this.base).toString();

      // If you use history.pushState with iframe.src = url, you will create 2 history entries,
      // but setting the `src` attribute imperatively will not.

      if (this._iframe) {
        Polymer.dom(this.$.demo).removeChild(this._iframe);
      }

      this._iframe = document.createElement('iframe');
      this._iframe.src = demoSrc;
      Polymer.dom(this.$.demo).appendChild(this._iframe);
    },

    _getDefaultActive: function() {
      var matchedPage;
      var url = this._srcUrl || this.base;
      var mainFile = url.replace(_baseUrl(this.base), '');

      function findMatch(list) {
        for (var item, i = 0; i < list.length; i++) {
          item = list[i];
          if (item && item.contentHref && item.contentHref.indexOf(mainFile) > 0) {
            return item;
          }
        }
        return null;
      }
      
      matchedPage = findMatch(this.docElements) || findMatch(this.docBehaviors);

      if (matchedPage) {
        return matchedPage.is;
      } else if (this.docElements.length > 0) {
        return this.docElements[0].is;
      } else if (this.docBehaviors.length > 0) {
        return this.docBehaviors[0].is;
      }
      return null;
    },

    _findDescriptor: function(name) {
      if (!this._analyzer) return null;

      var descriptor = this._analyzer.elementsByTagName[name];
      if (descriptor) return descriptor;

      for (var i = 0; i < this._analyzer.behaviors.length; i++) {
        if (this._analyzer.behaviors[i].is === name) {
          return this._analyzer.behaviors[i];
        }
      }
      return null;
    },

    _activeChanged: function(active, analyzer) {
      if (active === '') {
        this.active = this._getDefaultActive();
        return;
      }
      this.async(function() { this.$.active.value = active; });
      if (analyzer && analyzer.elementsByTagName) {
        this.$.headerPanel.scroller.scrollTop = 0;
        this._activeDescriptor = this._findDescriptor(active);
        if (this._activeDescriptor) {
          var hasDemo;
          var demos = this._activeDescriptor.demos;
          if (this.view && demos && demos.length) {
            var parts = this.view.split(':');
            if (parts[0] == 'demo') {
              if (parts[1]) {
                hasDemo = demos.some(function(d, i) {
                  if (d.path == parts[1]) {
                    return true;
                  }
                });
              }
              if (!hasDemo) {
                this.view = 'demo:' + demos[0].path;
                hasDemo = true;
              }
            }
          }
          if (!hasDemo == undefined) {
            this.view = 'docs';
          }
          if (this._activeDescriptor.is && !document.title) {
            document.title = this._activeDescriptor.is + " documentation";
          }
        }
        this._setDocDemos(this._activeDescriptor ? this._activeDescriptor.demos : []);
      }
    },

    _loadingChanged: function() {
      this.toggleClass('loaded', !this._loading);
    },

    _detectLoading: function() {
      this._loading = this.docSrc ? this._ajaxLoading : this._hydroLoading;
    },

    _analyzerChanged: function() {
      var analyzer = this._analyzer;
      this._setDocElements(analyzer && analyzer.elements ? analyzer.elements : []);
      this._setDocBehaviors(analyzer && analyzer.behaviors ? analyzer.behaviors : []);

      if (!this._findDescriptor(this.active)) {
        this.active = this._getDefaultActive();
      }
    },
    _detectAnalyzer: function() {
      this._analyzer = this.docSrc ? this._ajaxDesc : this._hydroDesc;
    },

    _handleAjaxResponse: function(e, req) {
      this._ajaxLoading = false;
      this._ajaxLastUrl = req.url;
      this._ajaxDesc = req.response;
    },

    _handleComponentSelectedEvent: function(ev) {
      var descriptor = this._findDescriptor(ev.detail);
      if (!descriptor) {
        console.warn("Could not navigate to ", ev.detail);
      }
      else {
        this.active = ev.detail;
      }
    },

    /**
     * Renders this element into static HTML for offline use.
     *
     * This is mostly useful for debugging and one-off documentation generation.
     * If you want to integrate doc generation into your build process, you
     * probably want to be calling `hydrolysis.Analyzer.analyze()` directly.
     *
     * @return {string} The HTML for this element with all state baked in.
     */
    marshal: function() {
      var jsonText = JSON.stringify(this.docElements || [], null, '  ');
      return '<' + this.is + '>\n' +
             jsonText.replace(/</g, '&lt;').replace(/>/g, '&gt;') + '\n' +
             '</' + this.is + '>';
    },

    _demoView: function(path) {
      return "demo:" + path;
    },
    _viewType: function(view) {
      return view ? view.split(":")[0] : null;
    }
  });
})();
</script>