/***
 * Contains core SlickGrid classes.
 * @module Core
 * @namespace Slick
 */

(function($) {
    // register namespace
    $.extend(true, window, {
        "Slick": {
            "Event":        Event,
            "EventData":    EventData,
            "Range":        Range,
            "NonDataRow":   NonDataItem,
            "Group":        Group,
            "GroupTotals":  GroupTotals,
            "EditorLock":   EditorLock,

            /***
             * A global singleton editor lock.
             * @class GlobalEditorLock
             * @static
             * @constructor
             */
            "GlobalEditorLock": new EditorLock()
        }
    });

    /***
     * An event object for passing data to event handlers and letting them control propagation.
     * <p>This is pretty much identical to how W3C and jQuery implement events.</p>
     * @class EventData
     * @constructor
     */
    function EventData() {
        var isPropagationStopped = false;
        var isImmediatePropagationStopped = false;

        /***
         * Stops event from propagating up the DOM tree.
         * @method stopPropagation
         */
        this.stopPropagation = function() {
            isPropagationStopped = true;
        };

        /***
         * Returns whether stopPropagation was called on this event object.
         * @method isPropagationStopped
         * @return {Boolean}
         */
        this.isPropagationStopped = function() {
            return isPropagationStopped;
        };

        /***
         * Prevents the rest of the handlers from being executed.
         * @method stopImmediatePropagation
         */
        this.stopImmediatePropagation = function() {
            isImmediatePropagationStopped = true;
        };

        /***
         * Returns whether stopImmediatePropagation was called on this event object.\
         * @method isImmediatePropagationStopped
         * @return {Boolean}
         */
        this.isImmediatePropagationStopped = function() {
            return isImmediatePropagationStopped;
        }
    }

    /***
     * A simple publisher-subscriber implementation.
     * @class Event
     * @constructor
     */
    function Event() {
        var handlers = [];

        /***
         * Adds an event handler to be called when the event is fired.
         * <p>Event handler will receive two arguments - an <code>EventData</code> and the <code>data</code>
         * object the event was fired with.<p>
         * @method subscribe
         * @param fn {Function} Event handler.
         */
        this.subscribe = function(fn) {
            handlers.push(fn);
        };

        /***
         * Removes an event handler added with <code>subscribe(fn)</code>.
         * @method unsubscribe
         * @param fn {Function} Event handler to be removed.
         */
        this.unsubscribe = function(fn) {
            for (var i = handlers.length - 1; i >= 0; i--) {
                if (handlers[i] === fn) {
                    handlers.splice(i, 1);
                }
            }
        };

        /***
         * Fires an event notifying all subscribers.
         * @method notify
         * @param args {Object} Additional data object to be passed to all handlers.
         * @param e {EventData}
         *      Optional.
         *      An <code>EventData</code> object to be passed to all handlers.
         *      For DOM events, an existing W3C/jQuery event object can be passed in.
         * @param scope {Object}
         *      Optional.
         *      The scope ("this") within which the handler will be executed.
         *      If not specified, the scope will be set to the <code>Event</code> instance.
         */
        this.notify = function(args, e, scope) {
            e = e || new EventData();
            scope = scope || this;

            var returnValue;
            for (var i = 0; i < handlers.length && !(e.isPropagationStopped() || e.isImmediatePropagationStopped()); i++) {
                returnValue = handlers[i].call(scope, e, args);
            }

            return returnValue;
        };
    }

    /***
     * A structure containing a range of cells.
     * @class Range
     * @constructor
     * @param fromRow {Integer} Starting row.
     * @param fromCell {Integer} Starting cell.
     * @param toRow {Integer} Optional. Ending row. Defaults to <code>fromRow</code>.
     * @param toCell {Integer} Optional. Ending cell. Defaults to <code>fromCell</code>.
     */
    function Range(fromRow, fromCell, toRow, toCell) {
        if (toRow === undefined && toCell === undefined) {
            toRow = fromRow;
            toCell = fromCell;
        }

        /***
         * @property fromRow
         * @type {Integer}
         */
        this.fromRow = Math.min(fromRow, toRow);

        /***
         * @property fromCell
         * @type {Integer}
         */
        this.fromCell = Math.min(fromCell, toCell);

        /***
         * @property toRow
         * @type {Integer}
         */
        this.toRow = Math.max(fromRow, toRow);

        /***
         * @property toCell
         * @type {Integer}
         */
        this.toCell = Math.max(fromCell, toCell);

        /***
         * Returns whether a range represents a single row.
         * @method isSingleRow
         * @return {Boolean}
         */
        this.isSingleRow = function() {
            return this.fromRow == this.toRow;
        };

        /***
         * Returns whether a range represents a single cell.
         * @method isSingleCell
         * @return {Boolean}
         */
        this.isSingleCell = function() {
            return this.fromRow == this.toRow && this.fromCell == this.toCell;
        };

        /***
         * Returns whether a range contains a given cell.
         * @method contains
         * @param row {Integer}
         * @param cell {Integer}
         * @return {Boolean}
         */
        this.contains = function(row, cell) {
            return row >= this.fromRow && row <= this.toRow &&
                   cell >= this.fromCell && cell <= this.toCell;
        };

        /***
         * Returns a readable representation of a range.
         * @method toString
         * @return {String}
         */
        this.toString = function() {
            if (this.isSingleCell()) {
                return "(" + this.fromRow + ":" + this.fromCell + ")";
            }
            else {
                return "(" + this.fromRow + ":" + this.fromCell + " - " + this.toRow + ":" + this.toCell + ")";
            }
        }
    }


    /***
     * A base class that all special / non-data rows (like Group and GroupTotals) derive from.
     * @class NonDataItem
     * @constructor
     */
    function NonDataItem() {
        this.__nonDataRow = true;
    }


    /***
     * Information about a group of rows.
     * @class Group
     * @extends Slick.NonDataItem
     * @constructor
     */
    function Group() {
        this.__group = true;
        this.__updated = false;

        /***
         * Number of rows in the group.
         * @property count
         * @type {Integer}
         */
        this.count = 0;

        /***
         * Grouping value.
         * @property value
         * @type {Object}
         */
        this.value = null;

        /***
         * Formatted display value of the group.
         * @property title
         * @type {String}
         */
        this.title = null;

        /***
         * Whether a group is collapsed.
         * @property collapsed
         * @type {Boolean}
         */
        this.collapsed = false;

        /***
         * GroupTotals, if any.
         * @property totals
         * @type {GroupTotals}
         */
        this.totals = null;
    }

    Group.prototype = new NonDataItem();

    /***
     * Compares two Group instances.
     * @method equals
     * @return {Boolean}
     * @param group {Group} Group instance to compare to.
     */
    Group.prototype.equals = function(group) {
        return this.value === group.value &&
               this.count === group.count &&
               this.collapsed === group.collapsed;
    };

    /***
     * Information about group totals.
     * An instance of GroupTotals will be created for each totals row and passed to the aggregators
     * so that they can store arbitrary data in it.  That data can later be accessed by group totals
     * formatters during the display.
     * @class GroupTotals
     * @extends Slick.NonDataItem
     * @constructor
     */
    function GroupTotals() {
        this.__groupTotals = true;

        /***
         * Parent Group.
         * @param group
         * @type {Group}
         */
        this.group = null;
    }

    GroupTotals.prototype = new NonDataItem();

    /***
     * A locking helper to track the active edit controller and ensure that only a single controller
     * can be active at a time.  This prevents a whole class of state and validation synchronization
     * issues.  An edit controller (such as SlickGrid) can query if an active edit is in progress
     * and attempt a commit or cancel before proceeding.
     * @class EditorLock
     * @constructor
     */
    function EditorLock() {
        var activeEditController = null;

        /***
         * Returns true if a specified edit controller is active (has the edit lock).
         * If the parameter is not specified, returns true if any edit controller is active.
         * @method isActive
         * @param editController {EditController}
         * @return {Boolean}
         */
        this.isActive = function(editController) {
            return (editController ? activeEditController === editController : activeEditController !== null);
        };

        /***
         * Sets the specified edit controller as the active edit controller (acquire edit lock).
         * If another edit controller is already active, and exception will be thrown.
         * @method activate
         * @param editController {EditController} edit controller acquiring the lock
         */
        this.activate = function(editController) {
            if (editController === activeEditController) { // already activated?
                return;
            }
            if (activeEditController !== null) {
                throw "SlickGrid.EditorLock.activate: an editController is still active, can't activate another editController";
            }
            if (!editController.commitCurrentEdit) {
                throw "SlickGrid.EditorLock.activate: editController must implement .commitCurrentEdit()";
            }
            if (!editController.cancelCurrentEdit) {
                throw "SlickGrid.EditorLock.activate: editController must implement .cancelCurrentEdit()";
            }
            activeEditController = editController;
        };

        /***
         * Unsets the specified edit controller as the active edit controller (release edit lock).
         * If the specified edit controller is not the active one, an exception will be thrown.
         * @method deactivate
         * @param editController {EditController} edit controller releasing the lock
         */
        this.deactivate = function(editController) {
            if (activeEditController !== editController) {
                throw "SlickGrid.EditorLock.deactivate: specified editController is not the currently active one";
            }
            activeEditController = null;
        };

        /***
         * Attempts to commit the current edit by calling "commitCurrentEdit" method on the active edit
         * controller and returns whether the commit attempt was successful (commit may fail due to validation
         * errors, etc.).  Edit controller's "commitCurrentEdit" must return true if the commit has succeeded
         * and false otherwise.  If no edit controller is active, returns true.
         * @method commitCurrentEdit
         * @return {Boolean}
         */
        this.commitCurrentEdit = function() {
            return (activeEditController ? activeEditController.commitCurrentEdit() : true);
        };

        /***
         * Attempts to cancel the current edit by calling "cancelCurrentEdit" method on the active edit
         * controller and returns whether the edit was successfully cancelled.  If no edit controller is
         * active, returns true.
         * @method cancelCurrentEdit
         * @return {Boolean}
         */
        this.cancelCurrentEdit = function cancelCurrentEdit() {
            return (activeEditController ? activeEditController.cancelCurrentEdit() : true);
        };
    }
})(jQuery);