/*!
 * jquery.event.drag - v 2.3.0
 * Copyright (c) 2010 Three Dub Media - http://threedubmedia.com
 * Open Source MIT License - http://threedubmedia.com/code/license
 */
// Created: 2008-06-04
// Updated: 2012-05-21
// Updated: 2016-08-16   Luiz Gonzaga dos Santos Filho
// REQUIRES: jquery 1.8 +, , event.drag 2.3.0
// TESTED WITH: jQuery 1.8.3, 1.11.2, 2.2.4, and 3.1.0

;(function( $ ) {
    // add the jquery instance method
    $.fn.drag = function( str, arg, opts ){
        // figure out the event type
        var type = typeof str == "string" ? str : "",
            // figure out the event handler...
            fn = $.isFunction( str ) ? str : $.isFunction( arg ) ? arg : null;
        // fix the event type
        if ( type.indexOf("drag") !== 0 )
            type = "drag"+ type;
        // were options passed
        opts = ( str == fn ? arg : opts ) || {};
        // trigger or bind event handler
        return fn ? this.on( type, opts, fn ) : this.trigger( type );
    };

    // local refs (increase compression)
    var $event = $.event,
        $special = $event.special,
        // configure the drag special event
        drag = $special.drag = {

            // these are the default settings
            defaults: {
                which: 1, // mouse button pressed to start drag sequence
                distance: 0, // distance dragged before dragstart
                not: ':input', // selector to suppress dragging on target elements
                handle: null, // selector to match handle target elements
                relative: false, // true to use "position", false to use "offset"
                drop: true, // false to suppress drop events, true or selector to allow
                click: false // false to suppress click events after dragend (no proxy)
            },

            // the key name for stored drag data
            datakey: "dragdata",

            // prevent bubbling for better performance
            noBubble: true,

            // count bound related events
            add: function( obj ){
                // read the interaction data
                var data = $.data( this, drag.datakey ),
                    // read any passed options
                    opts = obj.data || {};
                // count another realted event
                data.related += 1;
                // extend data options bound with this event
                // don't iterate "opts" in case it is a node
                $.each( drag.defaults, function( key, def ){
                    if ( opts[ key ] !== undefined )
                        data[ key ] = opts[ key ];
                });
            },

            // forget unbound related events
            remove: function(){
                $.data( this, drag.datakey ).related -= 1;
            },

            // configure interaction, capture settings
            setup: function(){
                // check for related events
                if ( $.data( this, drag.datakey ) )
                    return;
                // initialize the drag data with copied defaults
                var data = $.extend({ related:0 }, drag.defaults );
                // store the interaction data
                $.data( this, drag.datakey, data );
                // bind the mousedown event, which starts drag interactions
                $event.add( this, "touchstart mousedown", drag.init, data );
                // prevent image dragging in IE...
                if ( this.attachEvent )
                    this.attachEvent("ondragstart", drag.dontstart );
            },

            // destroy configured interaction
            teardown: function(){
                var data = $.data( this, drag.datakey ) || {};
                // check for related events
                if ( data.related )
                    return;
                // remove the stored data
                $.removeData( this, drag.datakey );
                // remove the mousedown event
                $event.remove( this, "touchstart mousedown", drag.init );
                // enable text selection
                drag.textselect( true );
                // un-prevent image dragging in IE...
                if ( this.detachEvent )
                    this.detachEvent("ondragstart", drag.dontstart );
            },

            // initialize the interaction
            init: function( event ){
                // sorry, only one touch at a time
                if ( drag.touched )
                    return;
                // the drag/drop interaction data
                var dd = event.data, results;
                // check the which directive
                if ( event.which != 0 && dd.which > 0 && event.which != dd.which )
                    return;
                // check for suppressed selector
                if ( $( event.target ).is( dd.not ) )
                    return;
                // check for handle selector
                if ( dd.handle && !$( event.target ).closest( dd.handle, event.currentTarget ).length )
                    return;

                drag.touched = event.type == 'touchstart' ? this : null;
                dd.propagates = 1;
                dd.mousedown = this;
                dd.interactions = [ drag.interaction( this, dd ) ];
                dd.target = event.target;
                dd.pageX = event.pageX;
                dd.pageY = event.pageY;
                dd.dragging = null;
                // handle draginit event...
                results = drag.hijack( event, "draginit", dd );
                // early cancel
                if ( !dd.propagates )
                    return;
                // flatten the result set
                results = drag.flatten( results );
                // insert new interaction elements
                if ( results && results.length ){
                    dd.interactions = [];
                    $.each( results, function(){
                        dd.interactions.push( drag.interaction( this, dd ) );
                    });
                }
                // remember how many interactions are propagating
                dd.propagates = dd.interactions.length;
                // locate and init the drop targets
                if ( dd.drop !== false && $special.drop )
                    $special.drop.handler( event, dd );
                // disable text selection
                drag.textselect( false );
                // bind additional events...
                if ( drag.touched )
                    $event.add( drag.touched, "touchmove touchend", drag.handler, dd );
                else
                    $event.add( document, "mousemove mouseup", drag.handler, dd );
                // helps prevent text selection or scrolling
                if ( !drag.touched || dd.live )
                    return false;
            },

            // returns an interaction object
            interaction: function( elem, dd ){
                var offset = (elem && elem.ownerDocument) 
                    ? $( elem )[ dd.relative ? "position" : "offset" ]() || { top:0, left:0 }
                    : { top: 0, left: 0 };
                return {
                    drag: elem,
                    callback: new drag.callback(),
                    droppable: [],
                    offset: offset
                };
            },

            // handle drag-releatd DOM events
            handler: function( event ){
                // read the data before hijacking anything
                var dd = event.data;
                // handle various events
                switch ( event.type ){
                    // mousemove, check distance, start dragging
                    case !dd.dragging && 'touchmove':
                        event.preventDefault();
                    case !dd.dragging && 'mousemove':
                        //  drag tolerance, x² + y² = distance²
                        if ( Math.pow(  event.pageX-dd.pageX, 2 ) + Math.pow(  event.pageY-dd.pageY, 2 ) < Math.pow( dd.distance, 2 ) )
                            break; // distance tolerance not reached
                        event.target = dd.target; // force target from "mousedown" event (fix distance issue)
                        drag.hijack( event, "dragstart", dd ); // trigger "dragstart"
                        if ( dd.propagates ) // "dragstart" not rejected
                            dd.dragging = true; // activate interaction
                        // mousemove, dragging
                    case 'touchmove':
                        event.preventDefault();
                    case 'mousemove':
                        if ( dd.dragging ){
                            // trigger "drag"
                            drag.hijack( event, "drag", dd );
                            if ( dd.propagates ){
                                // manage drop events
                                if ( dd.drop !== false && $special.drop )
                                    $special.drop.handler( event, dd ); // "dropstart", "dropend"
                                break; // "drag" not rejected, stop
                            }
                            event.type = "mouseup"; // helps "drop" handler behave
                        }
                        // mouseup, stop dragging
                    case 'touchend':
                    case 'mouseup':
                    default:
                        if ( drag.touched )
                            $event.remove( drag.touched, "touchmove touchend", drag.handler ); // remove touch events
                        else
                            $event.remove( document, "mousemove mouseup", drag.handler ); // remove page events
                        if ( dd.dragging ){
                            if ( dd.drop !== false && $special.drop )
                                $special.drop.handler( event, dd ); // "drop"
                            drag.hijack( event, "dragend", dd ); // trigger "dragend"
                        }
                        drag.textselect( true ); // enable text selection
                        // if suppressing click events...
                        if ( dd.click === false && dd.dragging )
                            $.data( dd.mousedown, "suppress.click", new Date().getTime() + 5 );
                        dd.dragging = drag.touched = false; // deactivate element
                        break;
                }
            },

            // re-use event object for custom events
            hijack: function( event, type, dd, x, elem ){
                // not configured
                if ( !dd )
                    return;
                // remember the original event and type
                var orig = { event:event.originalEvent, type:event.type },
                    // is the event drag related or drog related?
                    mode = type.indexOf("drop") ? "drag" : "drop",
                    // iteration vars
                    result, i = x || 0, ia, $elems, callback,
                    len = !isNaN( x ) ? x : dd.interactions.length;
                // modify the event type
                event.type = type;
                // protects originalEvent from side-effects
                var noop = function(){};
                event.originalEvent = new jQuery.Event(orig.event, {
                    preventDefault: noop,
                    stopPropagation: noop,
                    stopImmediatePropagation: noop
                });
                // initialize the results
                dd.results = [];
                // handle each interacted element
                do if ( ia = dd.interactions[ i ] ){
                    // validate the interaction
                    if ( type !== "dragend" && ia.cancelled )
                        continue;
                    // set the dragdrop properties on the event object
                    callback = drag.properties( event, dd, ia );
                    // prepare for more results
                    ia.results = [];
                    // handle each element
                    $( elem || ia[ mode ] || dd.droppable ).each(function( p, subject ){
                        // identify drag or drop targets individually
                        callback.target = subject;
                        // force propagtion of the custom event
                        event.isPropagationStopped = function(){ return false; };
                        // handle the event
                        result = subject ? $event.dispatch.call( subject, event, callback ) : null;
                        // stop the drag interaction for this element
                        if ( result === false ){
                            if ( mode == "drag" ){
                                ia.cancelled = true;
                                dd.propagates -= 1;
                            }
                            if ( type == "drop" ){
                                ia[ mode ][p] = null;
                            }
                        }
                        // assign any dropinit elements
                        else if ( type == "dropinit" )
                            ia.droppable.push( drag.element( result ) || subject );
                        // accept a returned proxy element
                        if ( type == "dragstart" )
                            ia.proxy = $( drag.element( result ) || ia.drag )[0];
                        // remember this result
                        ia.results.push( result );
                        // forget the event result, for recycling
                        delete event.result;
                        // break on cancelled handler
                        if ( type !== "dropinit" )
                            return result;
                    });
                    // flatten the results
                    dd.results[ i ] = drag.flatten( ia.results );
                    // accept a set of valid drop targets
                    if ( type == "dropinit" )
                        ia.droppable = drag.flatten( ia.droppable );
                    // locate drop targets
                    if ( type == "dragstart" && !ia.cancelled )
                        callback.update();
                }
                while ( ++i < len )
                    // restore the original event & type
                    event.type = orig.type;
                    event.originalEvent = orig.event;
                    // return all handler results
                    return drag.flatten( dd.results );
            },

            // extend the callback object with drag/drop properties...
            properties: function( event, dd, ia ){
                var obj = ia.callback;
                // elements
                obj.drag = ia.drag;
                obj.proxy = ia.proxy || ia.drag;
                // starting mouse position
                obj.startX = dd.pageX;
                obj.startY = dd.pageY;
                // current distance dragged
                obj.deltaX = event.pageX - dd.pageX;
                obj.deltaY = event.pageY - dd.pageY;
                // original element position
                obj.originalX = ia.offset.left;
                obj.originalY = ia.offset.top;
                // adjusted element position
                obj.offsetX = obj.originalX + obj.deltaX;
                obj.offsetY = obj.originalY + obj.deltaY;
                // assign the drop targets information
                obj.drop = drag.flatten( ( ia.drop || [] ).slice() );
                obj.available = drag.flatten( ( ia.droppable || [] ).slice() );
                return obj;
            },

            // determine is the argument is an element or jquery instance
            element: function( arg ){
                if ( arg && ( arg.jquery || arg.nodeType == 1 ) )
                    return arg;
            },

            // flatten nested jquery objects and arrays into a single dimension array
            flatten: function( arr ){
                return $.map( arr, function( member ){
                    return member && member.jquery ? $.makeArray( member ) :
                        member && member.length ? drag.flatten( member ) : member;
                });
            },

            // toggles text selection attributes ON (true) or OFF (false)
            textselect: function( bool ){
                $( document )[ bool ? "off" : "on" ]("selectstart", drag.dontstart )
                    .css("MozUserSelect", bool ? "" : "none" );
                // .attr("unselectable", bool ? "off" : "on" )
                document.unselectable = bool ? "off" : "on";
            },

            // suppress "selectstart" and "ondragstart" events
            dontstart: function(){
                return false;
            },

            // a callback instance contructor
            callback: function(){}

        };

        // callback methods
        drag.callback.prototype = {
            update: function(){
                if ( $special.drop && this.available.length )
                    $.each( this.available, function( i ){
                        $special.drop.locate( this, i );
                    });
            }
        };

        // patch $.event.$dispatch to allow suppressing clicks
        var $dispatch = $event.dispatch;
        $event.dispatch = function( event ){
            if ( $.data( this, "suppress."+ event.type ) - new Date().getTime() > 0 ){
                $.removeData( this, "suppress."+ event.type );
                return;
            }
            return $dispatch.apply( this, arguments );
        };

        // share the same special event configuration with related events...
        $special.draginit = $special.dragstart = $special.dragend = drag;
})( jQuery );
