/**
 * Created by Estevao on 31-05-2015.
 */

/**
 * Showdown Converter class
 * @class
 * @param {object} [converterOptions]
 * @returns {Converter}
 */
showdown.Converter = function (converterOptions) {
  'use strict';

  var
      /**
       * Options used by this converter
       * @private
       * @type {{}}
       */
      options = {},

      /**
       * Language extensions used by this converter
       * @private
       * @type {Array}
       */
      langExtensions = [],

      /**
       * Output modifiers extensions used by this converter
       * @private
       * @type {Array}
       */
      outputModifiers = [],

      /**
       * Event listeners
       * @private
       * @type {{}}
       */
      listeners = {},

      /**
       * The flavor set in this converter
       */
      setConvFlavor = setFlavor,

      /**
       * Metadata of the document
       * @type {{parsed: {}, raw: string, format: string}}
       */
      metadata = {
        parsed: {},
        raw: '',
        format: ''
      };

  _constructor();

  /**
   * Converter constructor
   * @private
   */
  function _constructor () {
    converterOptions = converterOptions || {};

    for (var gOpt in globalOptions) {
      if (globalOptions.hasOwnProperty(gOpt)) {
        options[gOpt] = globalOptions[gOpt];
      }
    }

    // Merge options
    if (typeof converterOptions === 'object') {
      for (var opt in converterOptions) {
        if (converterOptions.hasOwnProperty(opt)) {
          options[opt] = converterOptions[opt];
        }
      }
    } else {
      throw Error('Converter expects the passed parameter to be an object, but ' + typeof converterOptions +
      ' was passed instead.');
    }

    if (options.extensions) {
      showdown.helper.forEach(options.extensions, _parseExtension);
    }
  }

  /**
   * Parse extension
   * @param {*} ext
   * @param {string} [name='']
   * @private
   */
  function _parseExtension (ext, name) {

    name = name || null;
    // If it's a string, the extension was previously loaded
    if (showdown.helper.isString(ext)) {
      ext = showdown.helper.stdExtName(ext);
      name = ext;

      // LEGACY_SUPPORT CODE
      if (showdown.extensions[ext]) {
        console.warn('DEPRECATION WARNING: ' + ext + ' is an old extension that uses a deprecated loading method.' +
          'Please inform the developer that the extension should be updated!');
        legacyExtensionLoading(showdown.extensions[ext], ext);
        return;
        // END LEGACY SUPPORT CODE

      } else if (!showdown.helper.isUndefined(extensions[ext])) {
        ext = extensions[ext];

      } else {
        throw Error('Extension "' + ext + '" could not be loaded. It was either not found or is not a valid extension.');
      }
    }

    if (typeof ext === 'function') {
      ext = ext();
    }

    if (!showdown.helper.isArray(ext)) {
      ext = [ext];
    }

    var validExt = validate(ext, name);
    if (!validExt.valid) {
      throw Error(validExt.error);
    }

    for (var i = 0; i < ext.length; ++i) {
      switch (ext[i].type) {

        case 'lang':
          langExtensions.push(ext[i]);
          break;

        case 'output':
          outputModifiers.push(ext[i]);
          break;
      }
      if (ext[i].hasOwnProperty('listeners')) {
        for (var ln in ext[i].listeners) {
          if (ext[i].listeners.hasOwnProperty(ln)) {
            listen(ln, ext[i].listeners[ln]);
          }
        }
      }
    }

  }

  /**
   * LEGACY_SUPPORT
   * @param {*} ext
   * @param {string} name
   */
  function legacyExtensionLoading (ext, name) {
    if (typeof ext === 'function') {
      ext = ext(new showdown.Converter());
    }
    if (!showdown.helper.isArray(ext)) {
      ext = [ext];
    }
    var valid = validate(ext, name);

    if (!valid.valid) {
      throw Error(valid.error);
    }

    for (var i = 0; i < ext.length; ++i) {
      switch (ext[i].type) {
        case 'lang':
          langExtensions.push(ext[i]);
          break;
        case 'output':
          outputModifiers.push(ext[i]);
          break;
        default:// should never reach here
          throw Error('Extension loader error: Type unrecognized!!!');
      }
    }
  }

  /**
   * Listen to an event
   * @param {string} name
   * @param {function} callback
   */
  function listen (name, callback) {
    if (!showdown.helper.isString(name)) {
      throw Error('Invalid argument in converter.listen() method: name must be a string, but ' + typeof name + ' given');
    }

    if (typeof callback !== 'function') {
      throw Error('Invalid argument in converter.listen() method: callback must be a function, but ' + typeof callback + ' given');
    }

    if (!listeners.hasOwnProperty(name)) {
      listeners[name] = [];
    }
    listeners[name].push(callback);
  }

  function rTrimInputText (text) {
    var rsp = text.match(/^\s*/)[0].length,
        rgx = new RegExp('^\\s{0,' + rsp + '}', 'gm');
    return text.replace(rgx, '');
  }

  /**
   * Dispatch an event
   * @private
   * @param {string} evtName Event name
   * @param {string} text Text
   * @param {{}} options Converter Options
   * @param {{}} globals
   * @returns {string}
   */
  this._dispatch = function dispatch (evtName, text, options, globals) {
    if (listeners.hasOwnProperty(evtName)) {
      for (var ei = 0; ei < listeners[evtName].length; ++ei) {
        var nText = listeners[evtName][ei](evtName, text, this, options, globals);
        if (nText && typeof nText !== 'undefined') {
          text = nText;
        }
      }
    }
    return text;
  };

  /**
   * Listen to an event
   * @param {string} name
   * @param {function} callback
   * @returns {showdown.Converter}
   */
  this.listen = function (name, callback) {
    listen(name, callback);
    return this;
  };

  /**
   * Converts a markdown string into HTML
   * @param {string} text
   * @returns {*}
   */
  this.makeHtml = function (text) {
    //check if text is not falsy
    if (!text) {
      return text;
    }

    var globals = {
      gHtmlBlocks:     [],
      gHtmlMdBlocks:   [],
      gHtmlSpans:      [],
      gUrls:           {},
      gTitles:         {},
      gDimensions:     {},
      gListLevel:      0,
      hashLinkCounts:  {},
      langExtensions:  langExtensions,
      outputModifiers: outputModifiers,
      converter:       this,
      ghCodeBlocks:    [],
      metadata: {
        parsed: {},
        raw: '',
        format: ''
      }
    };

    // This lets us use ¨ trema as an escape char to avoid md5 hashes
    // The choice of character is arbitrary; anything that isn't
    // magic in Markdown will work.
    text = text.replace(/¨/g, '¨T');

    // Replace $ with ¨D
    // RegExp interprets $ as a special character
    // when it's in a replacement string
    text = text.replace(/\$/g, '¨D');

    // Standardize line endings
    text = text.replace(/\r\n/g, '\n'); // DOS to Unix
    text = text.replace(/\r/g, '\n'); // Mac to Unix

    // Stardardize line spaces
    text = text.replace(/\u00A0/g, '&nbsp;');

    if (options.smartIndentationFix) {
      text = rTrimInputText(text);
    }

    // Make sure text begins and ends with a couple of newlines:
    text = '\n\n' + text + '\n\n';

    // detab
    text = showdown.subParser('detab')(text, options, globals);

    /**
     * Strip any lines consisting only of spaces and tabs.
     * This makes subsequent regexs easier to write, because we can
     * match consecutive blank lines with /\n+/ instead of something
     * contorted like /[ \t]*\n+/
     */
    text = text.replace(/^[ \t]+$/mg, '');

    //run languageExtensions
    showdown.helper.forEach(langExtensions, function (ext) {
      text = showdown.subParser('runExtension')(ext, text, options, globals);
    });

    // run the sub parsers
    text = showdown.subParser('metadata')(text, options, globals);
    text = showdown.subParser('hashPreCodeTags')(text, options, globals);
    text = showdown.subParser('githubCodeBlocks')(text, options, globals);
    text = showdown.subParser('hashHTMLBlocks')(text, options, globals);
    text = showdown.subParser('hashCodeTags')(text, options, globals);
    text = showdown.subParser('stripLinkDefinitions')(text, options, globals);
    text = showdown.subParser('blockGamut')(text, options, globals);
    text = showdown.subParser('unhashHTMLSpans')(text, options, globals);
    text = showdown.subParser('unescapeSpecialChars')(text, options, globals);

    // attacklab: Restore dollar signs
    text = text.replace(/¨D/g, '$$');

    // attacklab: Restore tremas
    text = text.replace(/¨T/g, '¨');

    // render a complete html document instead of a partial if the option is enabled
    text = showdown.subParser('completeHTMLDocument')(text, options, globals);

    // Run output modifiers
    showdown.helper.forEach(outputModifiers, function (ext) {
      text = showdown.subParser('runExtension')(ext, text, options, globals);
    });

    // update metadata
    metadata = globals.metadata;
    return text;
  };

  /**
   * Converts an HTML string into a markdown string
   * @param src
   * @param [HTMLParser] A WHATWG DOM and HTML parser, such as JSDOM. If none is supplied, window.document will be used.
   * @returns {string}
   */
  this.makeMarkdown = this.makeMd = function (src, HTMLParser) {

    // replace \r\n with \n
    src = src.replace(/\r\n/g, '\n');
    src = src.replace(/\r/g, '\n'); // old macs

    // due to an edge case, we need to find this: > <
    // to prevent removing of non silent white spaces
    // ex: <em>this is</em> <strong>sparta</strong>
    src = src.replace(/>[ \t]+</, '>¨NBSP;<');

    if (!HTMLParser) {
      if (window && window.document) {
        HTMLParser = window.document;
      } else {
        throw new Error('HTMLParser is undefined. If in a webworker or nodejs environment, you need to provide a WHATWG DOM and HTML such as JSDOM');
      }
    }

    var doc = HTMLParser.createElement('div');
    doc.innerHTML = src;

    var globals = {
      preList: substitutePreCodeTags(doc)
    };

    // remove all newlines and collapse spaces
    clean(doc);

    // some stuff, like accidental reference links must now be escaped
    // TODO
    // doc.innerHTML = doc.innerHTML.replace(/\[[\S\t ]]/);

    var nodes = doc.childNodes,
        mdDoc = '';

    for (var i = 0; i < nodes.length; i++) {
      mdDoc += showdown.subParser('makeMarkdown.node')(nodes[i], globals);
    }

    function clean (node) {
      for (var n = 0; n < node.childNodes.length; ++n) {
        var child = node.childNodes[n];
        if (child.nodeType === 3) {
          if (!/\S/.test(child.nodeValue)) {
            node.removeChild(child);
            --n;
          } else {
            child.nodeValue = child.nodeValue.split('\n').join(' ');
            child.nodeValue = child.nodeValue.replace(/(\s)+/g, '$1');
          }
        } else if (child.nodeType === 1) {
          clean(child);
        }
      }
    }

    // find all pre tags and replace contents with placeholder
    // we need this so that we can remove all indentation from html
    // to ease up parsing
    function substitutePreCodeTags (doc) {

      var pres = doc.querySelectorAll('pre'),
          presPH = [];

      for (var i = 0; i < pres.length; ++i) {

        if (pres[i].childElementCount === 1 && pres[i].firstChild.tagName.toLowerCase() === 'code') {
          var content = pres[i].firstChild.innerHTML.trim(),
              language = pres[i].firstChild.getAttribute('data-language') || '';

          // if data-language attribute is not defined, then we look for class language-*
          if (language === '') {
            var classes = pres[i].firstChild.className.split(' ');
            for (var c = 0; c < classes.length; ++c) {
              var matches = classes[c].match(/^language-(.+)$/);
              if (matches !== null) {
                language = matches[1];
                break;
              }
            }
          }

          // unescape html entities in content
          content = showdown.helper.unescapeHTMLEntities(content);

          presPH.push(content);
          pres[i].outerHTML = '<precode language="' + language + '" precodenum="' + i.toString() + '"></precode>';
        } else {
          presPH.push(pres[i].innerHTML);
          pres[i].innerHTML = '';
          pres[i].setAttribute('prenum', i.toString());
        }
      }
      return presPH;
    }

    return mdDoc;
  };

  /**
   * Set an option of this Converter instance
   * @param {string} key
   * @param {*} value
   */
  this.setOption = function (key, value) {
    options[key] = value;
  };

  /**
   * Get the option of this Converter instance
   * @param {string} key
   * @returns {*}
   */
  this.getOption = function (key) {
    return options[key];
  };

  /**
   * Get the options of this Converter instance
   * @returns {{}}
   */
  this.getOptions = function () {
    return options;
  };

  /**
   * Add extension to THIS converter
   * @param {{}} extension
   * @param {string} [name=null]
   */
  this.addExtension = function (extension, name) {
    name = name || null;
    _parseExtension(extension, name);
  };

  /**
   * Use a global registered extension with THIS converter
   * @param {string} extensionName Name of the previously registered extension
   */
  this.useExtension = function (extensionName) {
    _parseExtension(extensionName);
  };

  /**
   * Set the flavor THIS converter should use
   * @param {string} name
   */
  this.setFlavor = function (name) {
    if (!flavor.hasOwnProperty(name)) {
      throw Error(name + ' flavor was not found');
    }
    var preset = flavor[name];
    setConvFlavor = name;
    for (var option in preset) {
      if (preset.hasOwnProperty(option)) {
        options[option] = preset[option];
      }
    }
  };

  /**
   * Get the currently set flavor of this converter
   * @returns {string}
   */
  this.getFlavor = function () {
    return setConvFlavor;
  };

  /**
   * Remove an extension from THIS converter.
   * Note: This is a costly operation. It's better to initialize a new converter
   * and specify the extensions you wish to use
   * @param {Array} extension
   */
  this.removeExtension = function (extension) {
    if (!showdown.helper.isArray(extension)) {
      extension = [extension];
    }
    for (var a = 0; a < extension.length; ++a) {
      var ext = extension[a];
      for (var i = 0; i < langExtensions.length; ++i) {
        if (langExtensions[i] === ext) {
          langExtensions[i].splice(i, 1);
        }
      }
      for (var ii = 0; ii < outputModifiers.length; ++i) {
        if (outputModifiers[ii] === ext) {
          outputModifiers[ii].splice(i, 1);
        }
      }
    }
  };

  /**
   * Get all extension of THIS converter
   * @returns {{language: Array, output: Array}}
   */
  this.getAllExtensions = function () {
    return {
      language: langExtensions,
      output: outputModifiers
    };
  };

  /**
   * Get the metadata of the previously parsed document
   * @param raw
   * @returns {string|{}}
   */
  this.getMetadata = function (raw) {
    if (raw) {
      return metadata.raw;
    } else {
      return metadata.parsed;
    }
  };

  /**
   * Get the metadata format of the previously parsed document
   * @returns {string}
   */
  this.getMetadataFormat = function () {
    return metadata.format;
  };

  /**
   * Private: set a single key, value metadata pair
   * @param {string} key
   * @param {string} value
   */
  this._setMetadataPair = function (key, value) {
    metadata.parsed[key] = value;
  };

  /**
   * Private: set metadata format
   * @param {string} format
   */
  this._setMetadataFormat = function (format) {
    metadata.format = format;
  };

  /**
   * Private: set metadata raw text
   * @param {string} raw
   */
  this._setMetadataRaw = function (raw) {
    metadata.raw = raw;
  };
};