/* ===================================================
 * jqueryaddDropCap.js v1.0.1
 * ===================================================
 * (c) 2015 Nicolas Guillaume, Nice, France
 * addDropCap plugin may be freely distributed under the terms of the GNU GPL v2.0 or later license.
 *
 * License URI: http://www.gnu.org/licenses/gpl-2.0.html
 *
 * Target the first letter of the first element found in the wrapper
 *
 * =================================================== */
(function ( $ ) {
  //defaults
  var pluginName = 'addDropCap',
      defaults = {
          wrapper : ".entry-content",
          minwords : 50,
          skipSelectors : { //defines the selector to skip when parsing the wrapper also if they are children of an element
            tags : ['IMG' , 'IFRAME', 'H1', 'H2', 'H3', 'H4', 'H5', 'H6', 'BLOCKQUOTE'],
            classes : [],
            ids : []
          }
      };

  function Plugin( element, options ) {
    this.element = element;
    this.options = $.extend( {}, defaults, options) ;
    this._defaults = defaults;
    this._name = pluginName;
    this.init();
  }

  //can access this.element and this.option
  Plugin.prototype.init = function () {
    var $_target = this._get_dropcap_el();
    //if there's text and enough words, then apply a drop cap
    if ( $_target && this.options.minwords <= this._countWords( $_target.text() ) )
      this._may_be_add_dc( $_target );
  };


  //@return : $ element or false
  //recursive function. parse this.wrapper to find the first eligible element with text
  Plugin.prototype._get_dropcap_el = function( _requested_el ) {
    var $_first_el      = _requested_el || $( this.options.wrapper ).find( this.element ).first(),
        _first_el_text  = this._get_real_text( $_first_el.text() );

    if ( ! this._is_authorized( $_first_el ) && $_first_el.next().length )
      return this._get_dropcap_el( $_first_el.next() );
    else if ( this._is_authorized( $_first_el ) && _first_el_text )
      return $_first_el;
    else if ( $_first_el.next().length )
      return this._get_dropcap_el( $_first_el.next() );
    //get me out of here
    return;
  };

  //@return : string
  //clean spaces and special characters
  Plugin.prototype._get_real_text = function( _text ) {
    _text.replace(/&nbsp;/g, '').replace(/ /g, '');
    return this._removeSpecChars( _text );
  };

  //@return :boolean
  //check if the selector is in the 'to skip' list
  Plugin.prototype._is_authorized = function( $_el ) {
    //check if underscore is loaded first
    if ( 'function' != typeof(_) )
      return true;
    if ( ! $_el[0] || ! $_el[0].tagName )
      return;
    if ( ! this._is_tag_allowed( $_el ) )
      return;
    if ( ! this._are_children_tag_allowed( $_el ) )
      return;
    if ( ! this._is_selector_allowed( $_el, ['ids' , 'classes'] ) )
      return;

    return true;
  };


  //@return : void
  //at this stage, the target has text, no need to check it
  Plugin.prototype._may_be_add_dc = function( $_target ) {
    var // _first_el_text    = $_target.text(),
        _first_word       = '',
        _split_text       = $_target.text().replace(/ /g , '&nbsp;').split('&nbsp;');
    if ( ! _.isArray(_split_text) )
      return;

    //get the first word => it can't be a space due to previous treatment
    if ( _split_text.length )
      _first_word = _split_text[0];

    //cClean it
    _first_word = this._removeSpecChars( _first_word );

    if ( ! _first_word.charAt(0) )
      return;

    var _first_letter     = _first_word.charAt(0),
        _rest_of_word     = _first_word.substr(1),
        _drop_capped      = '',
        _html             = '';

    _first_letter = ['<span class="tc-dropcap">' , _first_letter, '</span>'].join('');
    _drop_capped = [ _first_letter , _rest_of_word ].join( '' );

    //replace the first occurence only
    _html = $_target.html().replace( _first_word , _drop_capped );

    //write
    $_target.html(_html);
  };


  /********
  * HELPERS
  *********/
  /*
  * @params string : ids or classes
  * @return boolean
  */
  Plugin.prototype._is_selector_allowed = function( $_el , sel_types ) {
    //check if option is well formed
    if ( 'object' != typeof( this.options.skipSelectors ) )
      return true;
    var self = this,
        _filtered = sel_types.filter( function( sel_typ ) { return false === self._is_sel_type_allowed( $_el, sel_typ ); } );
    return 0 === _filtered.length;
  };


  /*
  * @return boolean
  */
  Plugin.prototype._is_sel_type_allowed = function( $_el, sel_typ ) {
    //check if option is well formed
    if ( ! this.options.skipSelectors[sel_typ] || ! $.isArray( this.options.skipSelectors[sel_typ] ) )
      return true;

    var _attr = 'ids' == sel_typ ? 'id' : 'class';

    //check if option is well formed
    if ( 'object' != typeof(this.options.skipSelectors) || ! this.options.skipSelectors[sel_typ] || ! $.isArray( this.options.skipSelectors[sel_typ] )  )
      return true;

    var _elSels       = ! $_el.attr( _attr ) ? [] : $_el.attr( _attr ).split(' '),
        _selsToSkip   = this.options.skipSelectors[sel_typ],
        _current_filtered     = _elSels.filter( function( name ) { return -1 != $.inArray( name , _selsToSkip ) ;});

    var _pref = 'ids' == sel_typ ? '#' : '.',
        _children_filtered = _selsToSkip.filter( function( name ) {
          return 0 !== $_el.find(_pref + name).length;
        } );

    return 0 === $.merge( _current_filtered , _children_filtered ).length;
  };


  /*
  * @return boolean
  */
  Plugin.prototype._is_tag_allowed = function( $_el ) {
    //check if option is well formed
    if ( 'object' != typeof(this.options.skipSelectors) || ! _.isArray( this.options.skipSelectors.tags ) )
      return true;
    //Try to find current element tag name among the forbidden list
    return -1 == _.indexOf( _.map( this.options.skipSelectors.tags , function(_tag) { return _tag.toUpperCase(); } ), $_el[0].tagName );
  };


  /*
  * @return boolean
  */
  Plugin.prototype._are_children_tag_allowed = function( $_el ) {
    //check if option is well formed
    if ( 'object' != typeof(this.options.skipSelectors) || ! _.isArray( this.options.skipSelectors.tags ) )
      return true;
    //has children ?
    if ( 0 === $_el.children().length )
      return true;

    var //childTagName  = $_el.children().first()[0].tagName,
        _tagToSkip    = this.options.skipSelectors.tags,
        _filtered     = _tagToSkip.filter( function(_tag) { return 0 !== $_el.find(_tag).length;} );

    return 0 === _filtered.length;
  };


  //@return : number
  Plugin.prototype._countWords = function( _expr ) {
    if ( 'string' != typeof( _expr ) )
      return 0;
    _expr = _expr.replace('&nbsp;' , ' ');
    return (_expr.split(' ')).length;
  };

  //Remove all characters from string but alphanumeric and -
  //@return : string
  Plugin.prototype._removeSpecChars = function( _expr , _replaceBy ) {
    _replaceBy = _replaceBy || '';
    return 'string' == typeof(_expr) ? _expr.replace(/[^\w-?!\u00bf-\u00ff]/g, _replaceBy ) : '';
  };

  //@return : string or false
  Plugin.prototype._stripHtmlTags = function( expr ) {
    return ( expr && 'string' == typeof(expr) ) ? expr.replace(/(<([^>]+)>)/ig,"") : false;
  };


  /**********
  * CONSTRUCT
  **********/
  // prevents against multiple instantiations
  $.fn[pluginName] = function ( options ) {
      return this.each(function () {
          if (!$.data(this, 'plugin_' + pluginName)) {
              $.data(this, 'plugin_' + pluginName,
              new Plugin( this, options ));
          }
      });
  };
})( jQuery);