/**
 _ _____           _          _     _
 | |  __ \         (_)        | |   | |
 ___ ___ | | |__) |___  ___ _ ______ _| |__ | | ___
 / __/ _ \| |  _  // _ \/ __| |_  / _` | '_ \| |/ _ \
 | (_| (_) | | | \ \  __/\__ \ |/ / (_| | |_) | |  __/
 \___\___/|_|_|  \_\___||___/_/___\__,_|_.__/|_|\___|

 v 1.5 - a jQuery plug-in by Alvaro Prieto Lauroba

 Licences: MIT & GPL
 Feel free to use or modify this plugin as far as my full name is kept

 If you are going to use this plug-in in production environments it is
 strongly recommended to use its minified version: colResizable.min.js

 */

(function($){

  var d = $(document); 		//window object
  var h = $("head");			//head object
  var drag = null;			//reference to the current grip that is being dragged
  var tables = [];			//array of the already processed tables (table.id as key)
  var	count = 0;				//internal count to create unique IDs when needed.

  //common strings for packing
  var ID = "id";
  var PX = "px";
  var SIGNATURE ="JColResizer";
  var FLEX = "JCLRFlex";

  //short-cuts
  var I = parseInt;
  var M = Math;
  var ie = navigator.userAgent.indexOf('Trident/4.0')>0;
  var S;
  try{S = sessionStorage;}catch(e){}	//Firefox crashes when executed as local file system

  //append required CSS rules
  h.append("<style type='text/css'>  .JColResizer{/*table-layout:fixed;*/} .JColResizer td, .JColResizer th{overflow:hidden;padding-left:0!important; padding-right:0!important;}  .JCLRgrips{ height:0px; position:relative;} .JCLRgrip{margin-left:-5px; position:absolute; z-index:5; } .JCLRgrip .JColResizer{position:absolute;background-color:red;filter:alpha(opacity=1);opacity:0;width:10px;height:100%;cursor: e-resize;top:0px} .JCLRLastGrip{position:absolute; width:1px; } .JCLRgripDrag{ border-left:1px dotted black;	} .JCLRFlex{width:auto!important;}</style>");


  /**
   * Function to allow column resizing for table objects. It is the starting point to apply the plugin.
   * @param {DOM node} tb - reference to the DOM table object to be enhanced
   * @param {Object} options	- some customization values
   */
  var init = function( tb, options){
    var t = $(tb);										//the table object is wrapped
    t.opt = options;
    if(t.opt.disable) return destroy(t);				//the user is asking to destroy a previously colResized table
    var	id = t.id = t.attr(ID) || SIGNATURE+count++;	//its id is obtained, if null new one is generated
    t.p = t.opt.postbackSafe; 							//short-cut to detect postback safe
    if(!t.is("table") || tables[id] && !t.opt.partialRefresh) return; 		//if the object is not a table or if it was already processed then it is ignored.
    t.addClass(SIGNATURE).attr(ID, id).before('<div class="JCLRgrips"/>');	//the grips container object is added. Signature class forces table rendering in fixed-layout mode to prevent column's min-width
    t.g = []; t.c = []; t.w = t.width(); t.gc = t.prev(); t.f=t.opt.fixed;	//t.c and t.g are arrays of columns and grips respectively
    if(options.marginLeft) t.gc.css("marginLeft", options.marginLeft);  	//if the table contains margins, it must be specified
    if(options.marginRight) t.gc.css("marginRight", options.marginRight);  	//since there is no (direct) way to obtain margin values in its original units (%, em, ...)
    t.cs = I(ie? tb.cellSpacing || tb.currentStyle.borderSpacing :t.css('border-spacing'))||2;	//table cellspacing (not even jQuery is fully cross-browser)
    t.b  = I(ie? tb.border || tb.currentStyle.borderLeftWidth :t.css('border-left-width'))||1;	//outer border width (again cross-browser issues)
    // if(!(tb.style.width || tb.width)) t.width(t.width()); //I am not an IE fan at all, but it is a pity that only IE has the currentStyle attribute working as expected. For this reason I can not check easily if the table has an explicit width or if it is rendered as "auto"
    tables[id] = t; 	//the table object is stored using its id as key
    createGrips(t);		//grips are created

  };


  /**
   * This function allows to remove any enhancements performed by this plugin on a previously processed table.
   * @param {jQuery ref} t - table object
   */
  var destroy = function(t){
    var id=t.attr(ID), t=tables[id];		//its table object is found
    if(!t||!t.is("table")) return;			//if none, then it wasn't processed
    t.removeClass(SIGNATURE+" "+FLEX).gc.remove();	//class and grips are removed
    delete tables[id];						//clean up data
  };


  /**
   * Function to create all the grips associated with the table given by parameters
   * @param {jQuery ref} t - table object
   */
  var createGrips = function(t){

    var th = t.find(">thead>tr>th,>thead>tr>td");	//if table headers are specified in its semantically correct tag, are obtained
    if(!th.length) th = t.find(">tbody>tr:first>th,>tr:first>th,>tbody>tr:first>td, >tr:first>td");	 //but headers can also be included in different ways
    th = th.filter(":visible");					//filter invisible columns
    t.cg = t.find("col"); 						//a table can also contain a colgroup with col elements
    t.ln = th.length;							//table length is stored
    if(t.p && S && S[t.id])memento(t,th);		//if 'postbackSafe' is enabled and there is data for the current table, its coloumn layout is restored
    th.each(function(i){						//iterate through the table column headers
      var c = $(this); 						//jquery wrap for the current column
      var g = $(t.gc.append('<div class="JCLRgrip"></div>')[0].lastChild); //add the visual node to be used as grip
      g.append(t.opt.gripInnerHtml).append('<div class="'+SIGNATURE+'"></div>');
      if(i == t.ln-1){
        g.addClass("JCLRLastGrip");
        if(t.f) g.html("");
      }
      g.bind('touchstart mousedown', onGripMouseDown); //bind the mousedown event to start dragging

      g.t = t; g.i = i; g.c = c;	c.w =c.width();		//some values are stored in the grip's node data
      t.g.push(g); t.c.push(c);						//the current grip and column are added to its table object
      c.width(c.w).removeAttr("width");				//the width of the column is converted into pixel-based measurements
      g.data(SIGNATURE, {i:i, t:t.attr(ID), last: i == t.ln-1});	 //grip index and its table name are stored in the HTML
    });
    t.cg.removeAttr("width");	//remove the width attribute from elements in the colgroup
    syncGrips(t); 				//the grips are positioned according to the current table layout
    //there is a small problem, some cells in the table could contain dimension values interfering with the
    //width value set by this plugin. Those values are removed
    t.find('td, th').not(th).not('table th, table td').each(function(){
      $(this).removeAttr('width');	//the width attribute is removed from all table cells which are not nested in other tables and dont belong to the header
    });
    if(!t.f){
      t.removeAttr('width').addClass(FLEX); //if not fixed, let the table grow as needed
    }


  };


  /**
   * Function to allow the persistence of columns dimensions after a browser postback. It is based in
   * the HTML5 sessionStorage object, which can be emulated for older browsers using sessionstorage.js
   * @param {jQuery ref} t - table object
   * @param {jQuery ref} th - reference to the first row elements (only set in deserialization)
   */
  var memento = function(t, th){
    var w,m=0,i=0,aux =[],tw;
    if(th){										//in deserialization mode (after a postback)
      t.cg.removeAttr("width");
      if(t.opt.flush){ S[t.id] =""; return;} 	//if flush is activated, stored data is removed
      w = S[t.id].split(";");					//column widths is obtained
      tw = w[t.ln+1];
      if(!t.f && tw)	t.width(tw);			//it not fixed and table width data available its size is restored
      for(;i<t.ln;i++){						//for each column
        aux.push(100*w[i]/w[t.ln]+"%"); 	//width is stored in an array since it will be required again a couple of lines ahead
        th.eq(i).css("width", aux[i] ); 	//each column width in % is restored
      }
      for(i=0;i<t.ln;i++)
        t.cg.eq(i).css("width", aux[i]);	//this code is required in order to create an inline CSS rule with higher precedence than an existing CSS class in the "col" elements
    }else{							//in serialization mode (after resizing a column)
      S[t.id] ="";				//clean up previous data
      for(;i < t.c.length; i++){	//iterate through columns
        w = t.c[i].width();		//width is obtained
        S[t.id] += w+";";		//width is appended to the sessionStorage object using ID as key
        m+=w;					//carriage is updated to obtain the full size used by columns
      }
      S[t.id]+=m;							//the last item of the serialized string is the table's active area (width),
      //to be able to obtain % width value of each columns while deserializing
      if(!t.f) S[t.id] += ";"+t.width(); 	//if not fixed, table width is stored
    }
  };


  /**
   * Function that places each grip in the correct position according to the current table layout
   * @param {jQuery ref} t - table object
   */
  var syncGrips = function (t){
    t.gc.width(t.w);			//the grip's container width is updated
    for(var i=0; i<t.ln; i++){	//for each column
      var c = t.c[i];
      t.g[i].css({			//height and position of the grip is updated according to the table layout
        left: c.offset().left - t.offset().left + c.outerWidth(false) + t.cs / 2 + PX,
        height: t.opt.headerOnly? t.c[0].outerHeight(true) : t.outerHeight(true)
      });
    }
  };



  /**
   * This function updates column's width according to the horizontal position increment of the grip being
   * dragged. The function can be called while dragging if liveDragging is enabled and also from the onGripDragOver
   * event handler to synchronize grip's position with their related columns.
   * @param {jQuery ref} t - table object
   * @param {number} i - index of the grip being dragged
   * @param {bool} isOver - to identify when the function is being called from the onGripDragOver event
   */
  var syncCols = function(t,i,isOver){
    var inc = drag.x-drag.l, c = t.c[i], c2 = t.c[i+1];
    var w = c.w + inc;	var w2= c2.w- inc;	//their new width is obtained
    c.width( w + PX);
    t.cg.eq(i).width( w + PX);
    if(t.f){ //if fixed mode
      c2.width(w2 + PX);
      t.cg.eq(i+1).width( w2 + PX);
    }
    if(isOver){
      c.w=w;
      c2.w= t.f ? w2 : c2.w;
    }
  };


  /**
   * This function updates all columns width according to its real width. It must be taken into account that the
   * sum of all columns can exceed the table width in some cases (if fixed is set to false and table has some kind
   * of max-width).
   * @param {jQuery ref} t - table object
   */
  var applyBounds = function(t){
    var w = $.map(t.c, function(c){			//obtain real widths
      return c.width();
    });
    t.width(t.width()).removeClass(FLEX);	//prevent table width changes
    $.each(t.c, function(i,c){
      c.width(w[i]).w = w[i];				//set column widths applying bounds (table's max-width)
    });
    t.addClass(FLEX);						//allow table width changes
  };


  /**
   * Event handler used while dragging a grip. It checks if the next grip's position is valid and updates it.
   * @param {event} e - mousemove event binded to the window object
   */
  var onGripDrag = function(e){
    if(!drag) return;
    var t = drag.t;		//table object reference
    var oe = e.originalEvent.touches;
    var ox = oe ? oe[0].pageX : e.pageX;    //original position (touch or mouse)
    var x =  ox - drag.ox + drag.l;	        //next position according to horizontal mouse position increment
    var mw = t.opt.minWidth, i = drag.i ;	//cell's min width
    var l = t.cs*1.5 + mw + t.b;
    var last = i == t.ln-1;                 			//check if it is the last column's grip (usually hidden)
    var min = i? t.g[i-1].position().left+t.cs+mw: l;	//min position according to the contiguous cells
    var max = t.f ? 	//fixed mode?
        i == t.ln-1?
        t.w-l:
        t.g[i+1].position().left-t.cs-mw:
        Infinity; 								//max position according to the contiguous cells
    x = M.max(min, M.min(max, x));				//apply bounding
    drag.x = x;	 drag.css("left",  x + PX); 	//apply position increment
    if(last){									//if it is the last grip
      var c = t.c[drag.i];					//width of the last column is obtained
      drag.w = c.w + x- drag.l;
    }
    if(t.opt.liveDrag){ 			//if liveDrag is enabled
      if(last){
        c.width(drag.w);
        t.w = t.width();
      }else{
        syncCols(t,i); 			//columns are synchronized
      }
      syncGrips(t);
      var cb = t.opt.onDrag;							//check if there is an onDrag callback
      if (cb) { e.currentTarget = t[0]; cb(e); }		//if any, it is fired
    }
    return false; 	//prevent text selection while dragging
  };


  /**
   * Event handler fired when the dragging is over, updating table layout
   */
  var onGripDragOver = function(e){

    d.unbind('touchend.'+SIGNATURE+' mouseup.'+SIGNATURE).unbind('touchmove.'+SIGNATURE+' mousemove.'+SIGNATURE);
    $("head :last-child").remove(); 				//remove the dragging cursor style
    if(!drag) return;
    drag.removeClass(drag.t.opt.draggingClass);		//remove the grip's dragging css-class
    var t = drag.t;
    var cb = t.opt.onResize; 	    //get some values
    var i = drag.i;                 //column index
    var last = i == t.ln-1;         //check if it is the last column's grip (usually hidden)
    var c = t.g[i].c;               //the column being dragged
    if(last){
      c.width(drag.w);
      c.w = drag.w;
    }else{
      syncCols(t, i, true);	//the columns are updated
    }
    if(!t.f) applyBounds(t);	//if not fixed mode, then apply bounds to obtain real width values
    syncGrips(t);				//the grips are updated
    if (cb) { e.currentTarget = t[0]; cb(e); }	//if there is a callback function, it is fired
    if(t.p && S) memento(t); 						//if postbackSafe is enabled and there is sessionStorage support, the new layout is serialized and stored
    drag = null;									//since the grip's dragging is over
  };


  /**
   * Event handler fired when the grip's dragging is about to start. Its main goal is to set up events
   * and store some values used while dragging.
   * @param {event} e - grip's mousedown event
   */
  var onGripMouseDown = function(e){
    var o = $(this).data(SIGNATURE);			//retrieve grip's data
    var t = tables[o.t],  g = t.g[o.i];			//shortcuts for the table and grip objects
    var oe = e.originalEvent.touches;           //touch or mouse event?
    g.ox = oe? oe[0].pageX: e.pageX;            //the initial position is kept
    g.l = g.position().left;
    d.bind('touchmove.'+SIGNATURE+' mousemove.'+SIGNATURE, onGripDrag ).bind('touchend.'+SIGNATURE+' mouseup.'+SIGNATURE, onGripDragOver);	//mousemove and mouseup events are bound
    h.append("<style type='text/css'>*{cursor:"+ t.opt.dragCursor +"!important}</style>"); 	//change the mouse cursor
    g.addClass(t.opt.draggingClass); 	//add the dragging class (to allow some visual feedback)
    drag = g;							//the current grip is stored as the current dragging object
    if(t.c[o.i].l) for(var i=0,c; i<t.ln; i++){ c=t.c[i]; c.l = false; c.w= c.width(); } 	//if the colum is locked (after browser resize), then c.w must be updated
    return false; 	//prevent text selection
  };


  /**
   * Event handler fired when the browser is resized. The main purpose of this function is to update
   * table layout according to the browser's size synchronizing related grips
   */
  var onResize = function(){
    for(t in tables){
      var t = tables[t], i, mw=0;
      t.removeClass(SIGNATURE);						//firefox doesn't like layout-fixed in some cases
      if (t.f && t.w != t.width()) {					//if the the table's width has changed and it is in fixed mode
        t.w = t.width();							//its new value is kept the active cells area is obtained
        for(i=0; i<t.ln; i++) mw+= t.c[i].w;
        //cell rendering is not as trivial as it might seem, and it is slightly different for
        //each browser. In the beginning i had a big switch for each browser, but since the code
        //was extremely ugly now I use a different approach with several re-flows. This works
        //pretty well but it's a bit slower. For now, lets keep things simple...
        for(i=0; i<t.ln; i++) t.c[i].css("width", M.round(1000*t.c[i].w/mw)/10 + "%").l=true;
        //c.l locks the column, telling us that its c.w is outdated
      }
      syncGrips(t.addClass(SIGNATURE));
    }

  };


  //bind resize event, to update grips position
  $(window).bind('resize.'+SIGNATURE, onResize);


  /**
   * The plugin is added to the jQuery library
   * @param {Object} options -  an object that holds some basic customization values
   */
  $.fn.extend({
    colResizable: function(options) {
      var defaults = {

        //attributes:
        draggingClass: 'JCLRgripDrag',	//css-class used when a grip is being dragged (for visual feedback purposes)
        gripInnerHtml: '',				//if it is required to use a custom grip it can be done using some custom HTML
        liveDrag: false,				//enables table-layout updating while dragging
        fixed: true,                    //table width does not change if columns are resized
        minWidth: 15, 					//minimum width value in pixels allowed for a column
        headerOnly: false,				//specifies that the size of the the column resizing anchors will be bounded to the size of the first row
        hoverCursor: "e-resize",  		//cursor to be used on grip hover
        dragCursor: "e-resize",  		//cursor to be used while dragging
        postbackSafe: false, 			//when it is enabled, table layout can persist after postback or page refresh. It requires browsers with sessionStorage support (it can be emulated with sessionStorage.js).
        flush: false, 					//when postbakSafe is enabled, and it is required to prevent layout restoration after postback, 'flush' will remove its associated layout data
        marginLeft: null,				//in case the table contains any margins, colResizable needs to know the values used, e.g. "10%", "15em", "5px" ...
        marginRight: null, 				//in case the table contains any margins, colResizable needs to know the values used, e.g. "10%", "15em", "5px" ...
        disable: false,					//disables all the enhancements performed in a previously colResized table
        partialRefresh: false,			//can be used in combination with postbackSafe when the table is inside of an updatePanel

        //events:
        onDrag: null, 					//callback function to be fired during the column resizing process if liveDrag is enabled
        onResize: null					//callback function fired when the dragging process is over
      }
      var options =  $.extend(defaults, options);
      return this.each(function() {
        init( this, options);
      });
    }
  });
})(jQuery);