/*global angular */
/*
 jQuery UI Datepicker plugin wrapper

 @note If ≤ IE8 make sure you have a polyfill for Date.toISOString()
 @param [ui-date] {object} Options to pass to $.fn.datepicker() merged onto uiDateConfig
 */

angular.module('ui.date', [])

    .constant('uiDateConfig', {})

    .directive('uiDate', ['uiDateConfig', 'uiDateConverter', function (uiDateConfig, uiDateConverter) {
        'use strict';
        var options;
        options = {};
        angular.extend(options, uiDateConfig);
        return {
            require:'?ngModel',
            link:function (scope, element, attrs, controller) {
                var getOptions = function () {
                    return angular.extend({}, uiDateConfig, scope.$eval(attrs.uiDate));
                };
                var initDateWidget = function () {
                    var showing = false;
                    var opts = getOptions();

                    // If we have a controller (i.e. ngModelController) then wire it up
                    if (controller) {

                        // Set the view value in a $apply block when users selects
                        // (calling directive user's function too if provided)
                        var _onSelect = opts.onSelect || angular.noop;
                        opts.onSelect = function (value, picker) {
                            scope.$apply(function() {
                                showing = true;
                                controller.$setViewValue(element.datepicker('getDate'));
                                _onSelect(value, picker);
                                element.blur();
                            });
                        };

                        var _beforeShow = opts.beforeShow || angular.noop;
                        opts.beforeShow = function(input, picker) {
                            showing = true;
                            _beforeShow(input, picker);
                        };

                        var _onClose = opts.onClose || angular.noop;
                        opts.onClose = function(value, picker) {
                            showing = false;
                            _onClose(value, picker);
                        };
                        element.off('blur.datepicker').on('blur.datepicker', function() {
                            if ( !showing ) {
                                scope.$apply(function() {
                                    element.datepicker('setDate', element.datepicker('getDate'));
                                    controller.$setViewValue(element.datepicker('getDate'));
                                });
                            }
                        });

                        // Update the date picker when the model changes
                        controller.$render = function () {
                            var date = controller.$modelValue;
                            if ( angular.isDefined(date) && date !== null && !angular.isDate(date) ) {
                                if ( angular.isString(controller.$modelValue) ) {
                                    date = uiDateConverter.stringToDate(attrs.uiDateFormat, controller.$modelValue);
                                } else {
                                    throw new Error('ng-Model value must be a Date, or a String object with a date formatter - currently it is a ' + typeof date + ' - use ui-date-format to convert it from a string');
                                }
                            }
                            element.datepicker('setDate', date);
                        };
                    }
                    // Check if the element already has a datepicker.
                    if (element.data('datepicker')) {
                        // Updates the datepicker options
                        element.datepicker('option', opts);
                        element.datepicker('refresh');
                    } else {
                        // Creates the new datepicker widget
                        element.datepicker(opts);

                        //Cleanup on destroy, prevent memory leaking
                        element.on('$destroy', function () {
                            element.datepicker('destroy');
                        });
                    }

                    if ( controller ) {
                        // Force a render to override whatever is in the input text box
                        controller.$render();
                    }
                };
                // Watch for changes to the directives options
                scope.$watch(getOptions, initDateWidget, true);
            }
        };
    }
    ])
    .factory('uiDateConverter', ['uiDateFormatConfig', function(uiDateFormatConfig){

        function dateToString(dateFormat, value){
            dateFormat = dateFormat || uiDateFormatConfig;
            if (value) {
                if (dateFormat) {
                    return jQuery.datepicker.formatDate(dateFormat, value);
                }

                if (value.toISOString) {
                    return value.toISOString();
                }
            }
            return null;
        }

        function stringToDate(dateFormat, value) {
            dateFormat = dateFormat || uiDateFormatConfig;
            if ( angular.isString(value) ) {
                if (dateFormat) {
                    return jQuery.datepicker.parseDate(dateFormat, value);
                }

                var isoDate = new Date(value);
                return isNaN(isoDate.getTime()) ? null : isoDate;
            }
            return null;
        }

        return {
            stringToDate: stringToDate,
            dateToString: dateToString
        };

    }])
    .constant('uiDateFormatConfig', '')
    .directive('uiDateFormat', ['uiDateConverter', function(uiDateConverter) {
        var directive = {
            require:'ngModel',
            link: function(scope, element, attrs, modelCtrl) {
                var dateFormat = attrs.uiDateFormat;

                // Use the datepicker with the attribute value as the dateFormat string to convert to and from a string
                modelCtrl.$formatters.unshift(function(value) {
                    return uiDateConverter.stringToDate(dateFormat, value);
                });

                modelCtrl.$parsers.push(function(value){
                    return uiDateConverter.dateToString(dateFormat, value);
                });

            }
        };

        return directive;
    }]);