/*
  The MIT License (MIT)

  Copyright (c) <2013> <Ren Aysha>

  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:

  The above copyright notice and this permission notice shall be included in
  all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  THE SOFTWARE.
*/

if ( typeof Object.create !== 'function' ) {
  Object.create = function( obj ) {
    function F() {}
    F.prototype = obj;
    return new F();
  };
}

(function( $, window, document, undefined ) {
  "use strict";

  var Anchorific = {

    init: function( options, elem ) {
      var self = this;

      self.elem = elem;
      self.$elem = $( elem );

      self.opt = $.extend( {},  this.opt, options );

      self.headers = self.$elem.find( self.opt.headers );
      self.previous = 0;

      // Fix bug #1
      if ( self.headers.length !== 0 ) {
        self.first = parseInt( self.headers.prop( 'nodeName' ).substring( 1 ), null );
      }

      self.build();
    },

    opt: {
      navigation: '.anchorific', // position of navigation
      headers: 'h1, h2, h3, h4, h5, h6',
      speed: 200, // speed of sliding back to top
      anchorClass: 'ae-anchor', // class of anchor links
      anchorText: 'TOP', // prepended or appended to anchor headings
      top: '.ae-top', // back to top button or link class
      spy: true, // scroll spy
      position: 'append', // position of anchor text
      spyOffset: !0 // specify heading offset for spy scrolling
    },

    build: function() {
      var self = this, obj, navigations = function() {};
      // when navigation configuration is set
      if ( self.opt.navigation ) {
        $( self.opt.navigation ).append( '<ul />' );
        self.previous = $( self.opt.navigation ).find( 'ul' ).last();
        navigations = function( obj ) {
          return self.navigations( obj );
        };
      }

      for( var i = 0; i < self.headers.length; i++ ) {
        obj = self.headers.eq( i );
        navigations( obj );
        self.anchor( obj );
      }

      if ( self.opt.spy )
        self.spy();

      if ( self.opt.top )
        self.back();
    },

    navigations: function( obj ) {
      var self = this, link, list, which, name = self.name( obj );

      if ( obj.attr( 'id' ) !== undefined )
        name = obj.attr( 'id' );

      link = $( '<a />' ).attr( 'href', '#' + name ).text( obj.text() );
      list = $( '<li />' ).append( link );

      which = parseInt( obj.prop( 'nodeName' ).substring( 1 ), null );
      list.attr( 'data-tag', which );

      self.subheadings( which, list );

      self.first = which;
    },

    subheadings: function( which, a ) {
      var self = this, ul = $( self.opt.navigation ).find( 'ul' ),
        li = $( self.opt.navigation ).find( 'li' );

      if ( which === self.first ) {
        self.previous.append( a );
      } else if ( which > self.first ) {
        li.last().append( '<ul />' );
        // can't use cache ul; need to find ul once more
        $( self.opt.navigation ).find( 'ul' ).last().append( a );
        self.previous = a.parent();
      } else {
        $( 'li[data-tag=' + which + ']' ).last().parent().append( a );
        self.previous = a.parent();
      }
    },

    name: function( obj ) {
      var name = obj.text().replace( /[^\w\s]/gi, '' )
                .replace( /\s+/g, '-' )
                .toLowerCase();

      return name;
    },

    anchor: function( obj ) {
      var self = this, name = self.name( obj ), anchor, text = self.opt.anchorText,
        klass = self.opt.anchorClass, id;

      if ( obj.attr( 'id' ) === undefined )
        obj.attr( 'id', name );

      id = obj.attr( 'id' );

      anchor = $( '<a />' ).attr( 'href', '#').html( text ).addClass( klass );

      if ( self.opt.position === 'append' ) {
        obj.append( anchor );
      } else {
        obj.prepend( anchor );
      }
    },

    back: function() {
      var self = this, body = $( 'body, html' ), top = $( self.opt.top );

      top.on( 'click', function( e ) {
        e.preventDefault();

        body.animate({
          'scrollTop': 0
        }, self.opt.speed );
      });
    },

    top: function( that ) {
      var self = this, top = self.opt.top, back;

      if ( top !== false ) {
        back = ( $( that ).scrollTop() > 200 ) ?
            $( top ).fadeIn() :
            $( top ).fadeOut();
      }
    },

    spy: function() {
      var self = this, previous, current, list, top, prev;

      $( window ).scroll( function( e ) {
        // show links back to top
        self.top( this );
        // get all the header on top of the viewport
        current = self.headers.map( function( e ) {
          if ( ( $( this ).offset().top - $( window ).scrollTop() ) < self.opt.spyOffset ) {
            return this;
          }
        });
        // get only the latest header on the viewport
        current = $( current ).eq( current.length - 1 );

        if ( current && current.length ) {
          // get all li tag that contains href of # ( all the parents )
          list = $( 'li:has(a[href="#' + current.attr( 'id' ) + '"])' );

          if ( prev !== undefined ) {
            prev.removeClass( 'active' );
          }

          list.addClass( 'active' );
          prev = list;
        }
      });
    }
  };

  $.fn.anchorific = function( options ) {
    return this.each(function() {
      if ( ! $.data( this, 'anchorific' ) ) {
        var anchor = Object.create( Anchorific );

        anchor.init( options, this );

        $.data( this, 'anchorific', anchor );
      }
    });
  };

})( jQuery, window, document );