var Datepicker;

(function (window, $, undefined) {
    var pluginName = 'datepicker',
        $body, $datepickersContainer,
        containerBuilt = false,
        baseTemplate = '' +
            '<div class="datepicker">' +
            '<nav class="datepicker--nav"></nav>' +
            '<div class="datepicker--content"></div>' +
            '</div>',
        defaults = {
            inline: false,
            language: 'ru',
            startDate: new Date(),
            firstDay: '',
            weekends: [6, 0],
            dateFormat: '',
            toggleSelected: true,

            position: 'bottom left',
            offset: 8,

            view: 'days',
            minView: 'days',

            showOtherMonths: true,
            selectOtherMonths: true,
            moveToOtherMonthsOnSelect: true,

            showOtherYears: true,
            selectOtherYears: true,
            moveToOtherYearsOnSelect: true,

            minDate: '',
            maxDate: '',
            disableNavWhenOutOfRange: true,

            multipleDates: false, // Boolean or Number
            multipleDatesSeparator: ',',

            todayButton: false,
            clearButton: false,

            showEvent: 'focus',
            autoClose: false,

            // navigation
            prevHtml: '&laquo;',
            nextHtml: '&raquo;',
            navTitles: {
                days: 'MM, yyyy',
                months: 'yyyy',
                years: 'yyyy1 - yyyy2'
            },

            // events
            onSelect: '',
            onChangeMonth: '',
            onChangeYear: '',
            onChangeDecade: '',
            onChangeView: '',
            onRenderCell: ''
        };

    Datepicker  = function (el, options) {
        this.el = el;
        this.$el = $(el);

        this.opts = $.extend(true, {}, defaults, options);

        if ($body == undefined) {
            $body = $('body');
        }

        if (!this.opts.startDate) {
            this.opts.startDate = new Date();
        }

        if (this.el.nodeName == 'INPUT') {
            this.elIsInput = true;
        }

        this.inited = false;
        this.visible = false;
        this.silent = false; // Need to prevent unnecessary rendering

        this.currentDate = this.opts.startDate;
        this.currentView = this.opts.view;
        this._createShortCuts();
        this.selectedDates = [];
        this.views = {};

        this.init()
    };


    Datepicker.prototype = {
        viewIndexes: ['days', 'months', 'years'],

        init: function () {
            if (!containerBuilt && !this.opts.inline && this.elIsInput) {
                this._buildDatepickersContainer();
            }
            this._buildBaseHtml();
            this._defineLocale(this.opts.language);
            this._syncWithMinMaxDates();

            if (this.elIsInput) {
                if (!this.opts.inline) {
                    // Set extra classes for proper transitions
                    this._setPositionClasses(this.opts.position);
                    this._bindEvents()
                }
            }

            this.views[this.currentView] = new Datepicker.Body(this, this.currentView, this.opts);
            this.views[this.currentView].show();
            this.nav = new Datepicker.Navigation(this, this.opts);
            this.view = this.currentView;

            this.inited = true;
        },

        _createShortCuts: function () {

            this.minDate = this.opts.minDate ? this.opts.minDate : new Date(-8639999913600000);
            this.maxDate = this.opts.maxDate ? this.opts.maxDate : new Date(8639999913600000);
        },

        _bindEvents : function () {
            this.$el.on(this.opts.showEvent, this._onShowEvent.bind(this));
            this.$el.on('blur', this._onBlur.bind(this));
            this.$datepicker.on('mousedown', this._onMouseDownDatepicker.bind(this));
            this.$datepicker.on('mouseup', this._onMouseUpDatepicker.bind(this));
        },

        isWeekend: function (day) {
            return this.opts.weekends.indexOf(day) !== -1;
        },

        _defineLocale: function (lang) {
            if (typeof lang == 'string') {
                this.loc = Datepicker.language[lang];
                if (!this.loc) {
                    console.warn('Can\'t find language "' + lang + '" in Datepicker.language, will use "ru" instead');
                    this.loc = Datepicker.language.ru
                }
            } else {
                this.loc = $.extend({}, Datepicker.language.ru, lang)
            }

            if (this.opts.dateFormat) {
                this.loc.dateFormat = this.opts.dateFormat
            }

            if (this.opts.firstDay) {
                this.loc.firstDay = this.opts.firstDay
            }
        },

        _buildDatepickersContainer: function () {
            containerBuilt = true;
            $body.append('<div class="datepickers-container" id="datepickers-container"></div>');
            $datepickersContainer = $('#datepickers-container');
        },

        _buildBaseHtml: function () {
            var $appendTarget,
                $inline = $('<div class="datepicker-inline">');

            if(this.el.nodeName == 'INPUT') {
                if (!this.opts.inline) {
                    $appendTarget = $datepickersContainer;
                } else {
                    $appendTarget = $inline.insertAfter(this.$el)
                }
            } else {
                $appendTarget = $inline.insertAfter(this.$el)
            }

            this.$datepicker = $(baseTemplate).appendTo($appendTarget);
            this.$content = $('.datepicker--content', this.$datepicker);
            this.$nav = $('.datepicker--nav', this.$datepicker);
        },

        _triggerOnChange: function () {
            if (!this.selectedDates.length) {
                return this.opts.onSelect('', '', this);
            }

            var selectedDates = this.selectedDates,
                parsedSelected = Datepicker.getParsedDate(selectedDates[0]),
                formattedDates,
                _this = this,
                dates = new Date(parsedSelected.year, parsedSelected.month, parsedSelected.date);

                formattedDates = selectedDates.map(function (date) {
                    return _this.formatDate(_this.loc.dateFormat, date)
                }).join(this.opts.multipleDatesSeparator);

            // Create new dates array, to separate it from original selectedDates
            if (this.opts.multipleDates) {
                dates = selectedDates.map(function(date) {
                    var parsedDate = Datepicker.getParsedDate(date);
                    return new Date(parsedDate.year, parsedDate.month, parsedDate.date)
                })
            }

            this.opts.onSelect(formattedDates, dates, this);
        },

        next: function () {
            var d = this.parsedDate,
                o = this.opts;
            switch (this.view) {
                case 'days':
                    this.date = new Date(d.year, d.month + 1, 1);
                    if (o.onChangeMonth) o.onChangeMonth(d.month + 1);
                    break;
                case 'months':
                    this.date = new Date(d.year + 1, d.month, 1);
                    if (o.onChangeYear) o.onChangeYear(d.year + 1);
                    break;
                case 'years':
                    this.date = new Date(d.year + 10, 0, 1);
                    if (o.onChangeDecade) o.onChangeDecade(this.curDecade);
                    break;
            }
        },

        prev: function () {
            var d = this.parsedDate,
                o = this.opts;
            switch (this.view) {
                case 'days':
                    this.date = new Date(d.year, d.month - 1, 1);
                    if (o.onChangeMonth) o.onChangeMonth(d.month - 1);
                    break;
                case 'months':
                    this.date = new Date(d.year - 1, d.month, 1);
                    if (o.onChangeYear) o.onChangeYear(d.year - 1);
                    break;
                case 'years':
                    this.date = new Date(d.year - 10, 0, 1);
                    if (o.onChangeDecade) o.onChangeDecade(this.curDecade);
                    break;
            }
        },

        formatDate: function (string, date) {
            date = date || this.date;
            var result = string,
                locale = this.loc,
                decade = Datepicker.getDecade(date),
                d = Datepicker.getParsedDate(date);

            switch (true) {
                case /dd/.test(result):
                    result = result.replace(/\bdd\b/, d.fullDate);
                case /d/.test(result):
                    result = result.replace(/\bd\b/, d.date);
                case /DD/.test(result):
                    result = result.replace(/\bDD\b/, locale.days[d.day]);
                case /D/.test(result):
                    result = result.replace(/\bD\b/, locale.daysShort[d.day]);
                case /mm/.test(result):
                    result = result.replace(/\bmm\b/, d.fullMonth);
                case /m/.test(result):
                    result = result.replace(/\bm\b/, d.month + 1);
                case /MM/.test(result):
                    result = result.replace(/\bMM\b/, this.loc.months[d.month]);
                case /M/.test(result):
                    result = result.replace(/\bM\b/, locale.monthsShort[d.month]);
                case /yyyy/.test(result):
                    result = result.replace(/\byyyy\b/, d.year);
                case /yyyy1/.test(result):
                    result = result.replace(/\byyyy1\b/, decade[0]);
                case /yyyy2/.test(result):
                    result = result.replace(/\byyyy2\b/, decade[1]);
                case /yy/.test(result):
                    result = result.replace(/\byy\b/, d.year.toString().slice(-2));
            }

            return result;
        },

        selectDate: function (date) {
            var d = this.parsedDate,
                newDate = '';

            if (this.view == 'days') {
                if (date.getMonth() != d.month && this.opts.moveToOtherMonthsOnSelect) {
                    newDate = new Date(date.getFullYear(), date.getMonth(), 1);

                }
            }

            if (this.view == 'years') {
                if (date.getFullYear() != d.year && this.opts.moveToOtherYearsOnSelect) {
                    newDate = new Date(date.getFullYear(), 0, 1);
                }
            }

            if (newDate) {
                this.silent = true;
                this.date = newDate;
                this.silent = false;
                this.nav._render()
            }

            if (this.opts.multipleDates) {
                if (this.selectedDates.length === this.opts.multipleDates) return;
                if (!this._isSelected(date)) {
                    this.selectedDates.push(date);
                }
            } else {
                this.selectedDates = [date];
            }

            this._setInputValue();

            if (this.opts.onSelect) {
                this._triggerOnChange();
            }

            if (this.opts.autoClose) {
                this.hide();
            } else {
                this.views[this.currentView]._render()
            }
        },

        removeDate: function (date) {
            var selected = this.selectedDates,
                _this = this;

            return selected.some(function (curDate, i) {
                if (Datepicker.isSame(curDate, date)) {
                    selected.splice(i, 1);
                    _this.views[_this.currentView]._render();
                    _this._setInputValue();
                    if (_this.opts.onSelect) {
                        _this._triggerOnChange();
                    }
                    return true
                }
            })
        },

        today: function () {
            this.silent = true;
            this.view = this.opts.minView;
            this.silent = false;
            this.date = new Date();
        },

        clear: function () {
            this.selectedDates = [];
            this.views[this.currentView]._render();
            this._triggerOnChange()
        },

        /**
         * Updates datepicker options
         * @param {String|Object} param - parameter's name to update. If object then it will extend current options
         * @param {String|Number|Object} [value] - new param value
         */
        update: function (param, value) {
            var len = arguments.length;
            if (len == 2) {
                this.opts[param] = value;
            } else if (len == 1 && typeof param == 'object') {
                this.opts = $.extend(true, this.opts, param)
            }

            this._createShortCuts();
            this._syncWithMinMaxDates();
            this._defineLocale(this.opts.language);
            this.nav._addButtonsIfNeed();
            this.nav._render();
            this.views[this.currentView]._render();

            if (this.elIsInput && !this.opts.inline) {
                this._setPositionClasses(this.opts.position);
                if (this.visible) {
                    this.setPosition(this.opts.position)
                }
            }

            return this;
        },

        _syncWithMinMaxDates: function () {
            var curTime = this.date.getTime();
            this.silent = true;
            if (this.minTime > curTime) {
                this.date = this.minDate;
            }

            if (this.maxTime < curTime) {
                this.date = this.maxDate;
            }
            this.silent = false;
        },

        _isSelected: function (checkDate, cellType) {
            return this.selectedDates.some(function (date) {
                return Datepicker.isSame(date, checkDate, cellType)
            })
        },

        _setInputValue: function () {
            var _this = this,
                format = this.loc.dateFormat,
                value = this.selectedDates.map(function (date) {
                    return _this.formatDate(format, date)
                });

            value.join(this.opts.multipleDatesSeparator);

            this.$el.val(value)
        },

        /**
         * Check if date is between minDate and maxDate
         * @param date {object} - date object
         * @param type {string} - cell type
         * @returns {boolean}
         * @private
         */
        _isInRange: function (date, type) {
            var time = date.getTime(),
                d = Datepicker.getParsedDate(date),
                min = Datepicker.getParsedDate(this.minDate),
                max = Datepicker.getParsedDate(this.maxDate),
                dMinTime = new Date(d.year, d.month, min.date).getTime(),
                dMaxTime = new Date(d.year, d.month, max.date).getTime(),
                types = {
                    day: time >= this.minTime && time <= this.maxTime,
                    month: dMinTime >= this.minTime && dMaxTime <= this.maxTime,
                    year: d.year >= min.year && d.year <= max.year
                };
            return type ? types[type] : types.day
        },

        _getDimensions: function ($el) {
            var offset = $el.offset();

            return {
                width: $el.outerWidth(),
                height: $el.outerHeight(),
                left: offset.left,
                top: offset.top
            }
        },

        _setPositionClasses: function (pos) {
            pos = pos.split(' ');
            var main = pos[0],
                sec = pos[1],
                classes = 'datepicker -' + main + '-' + sec + '- -from-' + main + '-';

            if (this.visible) classes += ' active';

            this.$datepicker
                .removeAttr('class')
                .addClass(classes);
        },

        setPosition: function (position) {
            var dims = this._getDimensions(this.$el),
                selfDims = this._getDimensions(this.$datepicker),
                pos = position.split(' '),
                top, left,
                offset = this.opts.offset,
                main = pos[0],
                secondary = pos[1];

            switch (main) {
                case 'top':
                    top = dims.top - selfDims.height - offset;
                    break;
                case 'right':
                    left = dims.left + dims.width + offset;
                    break;
                case 'bottom':
                    top = dims.top + dims.height + offset;
                    break;
                case 'left':
                    left = dims.left - selfDims.width - offset;
                    break;
            }

            switch(secondary) {
                case 'top':
                    top = dims.top;
                    break;
                case 'right':
                    left = dims.left + dims.width - selfDims.width;
                    break;
                case 'bottom':
                    top = dims.top + dims.height - selfDims.height;
                    break;
                case 'left':
                    left = dims.left;
                    break;
                case 'center':
                    if (/left|right/.test(main)) {
                        top = dims.top + dims.height/2 - selfDims.height/2;
                    } else {
                        left = dims.left + dims.width/2 - selfDims.width/2;
                    }
            }

            this.$datepicker
                .css({
                    left: left,
                    top: top
                })
        },

        show: function () {
            this.setPosition(this.opts.position);
            this.$datepicker.addClass('active');
            this.visible = true;
        },

        hide: function () {
            this.$datepicker
                .removeClass('active')
                .css({
                    left: '-100000px'
                });

            this.inFocus = false;
            this.visible = false;
            this.$el.blur();
        },

        _onShowEvent: function () {
            if (!this.visible) {
                this.show();
            }
        },

        _onBlur: function () {
            if (!this.inFocus && this.visible) {
                this.hide();
            }
        },

        _onMouseDownDatepicker: function (e) {
            this.inFocus = true;
        },

        _onMouseUpDatepicker: function (e) {
            this.inFocus = false;
            this.$el.focus()
        },

        get parsedDate() {
            return Datepicker.getParsedDate(this.date);
        },

        set date (val) {
            this.currentDate = val;

            if (this.inited && !this.silent) {
                this.views[this.view]._render();
                this.nav._render();
            }

            return val;
        },

        get date () {
            return this.currentDate
        },

        set view (val) {
            this.viewIndex = this.viewIndexes.indexOf(val);

            if (this.viewIndex < 0) {
                return;
            }

            this.prevView = this.currentView;
            this.currentView = val;

            if (this.inited) {
                if (!this.views[val]) {
                    this.views[val] = new Datepicker.Body(this, val, this.opts)
                } else {
                    this.views[val]._render();
                }

                this.views[this.prevView].hide();
                this.views[val].show();
                this.nav._render();

                if (this.opts.onChangeView) {
                    this.opts.onChangeView(val)
                }
            }

            return val
        },

        get view() {
            return this.currentView;
        },

        get cellType() {
            return this.view.substring(0, this.view.length - 1)
        },

        get minTime() {
            var min = Datepicker.getParsedDate(this.minDate);
            return new Date(min.year, min.month, min.date).getTime()
        },

        get maxTime() {
            var max = Datepicker.getParsedDate(this.maxDate);
            return new Date(max.year, max.month, max.date).getTime()
        },

        get curDecade() {
            return Datepicker.getDecade(this.date)
        }
    };

    //  Utils
    // -------------------------------------------------

    Datepicker.getDaysCount = function (date) {
        return new Date(date.getFullYear(), date.getMonth() + 1, 0).getDate();
    };

    Datepicker.getParsedDate = function (date) {
        return {
            year: date.getFullYear(),
            month: date.getMonth(),
            fullMonth: (date.getMonth() + 1) < 10 ? '0' + (date.getMonth() + 1) : date.getMonth() + 1, // One based
            date: date.getDate(),
            fullDate: date.getDate() < 10 ? '0' + date.getDate() : date.getDate(),
            day: date.getDay()
        }
    };

    Datepicker.getDecade = function (date) {
        var firstYear = Math.floor(date.getFullYear() / 10) * 10;

        return [firstYear, firstYear + 9];
    };

    Datepicker.template = function (str, data) {
        return str.replace(/#\{([\w]+)\}/g, function (source, match) {
            if (data[match] || data[match] === 0) {
                return data[match]
            }
        });
    };

    Datepicker.isSame = function (date1, date2, type) {
        var d1 = Datepicker.getParsedDate(date1),
            d2 = Datepicker.getParsedDate(date2),
            _type = type ? type : 'day',

            conditions = {
                day: d1.date == d2.date && d1.month == d2.month && d1.year == d2.year,
                month: d1.month == d2.month && d1.year == d2.year,
                year: d1.year == d2.year
            };

        return conditions[_type];
    };

    Datepicker.language = {
        ru: {
            days: ['Воскресенье', 'Понедельник', 'Вторник', 'Среда', 'Четверг', 'Пятница', 'Суббота'],
            daysShort: ['Вос','Пон','Вто','Сре','Чет','Пят','Суб'],
            daysMin: ['Вс','Пн','Вт','Ср','Чт','Пт','Сб'],
            months: ['Январь', 'Февраль', 'Март', 'Апрель', 'Май', 'Июнь', 'Июль', 'Август', 'Сентябрь', 'Октябрь', 'Ноябрь', 'Декабрь'],
            monthsShort: ['Янв', 'Фев', 'Мар', 'Апр', 'Май', 'Июн', 'Июл', 'Авг', 'Сен', 'Окт', 'Ноя', 'Дек'],
            today: 'Сегодня',
            clear: 'Очистить',
            dateFormat: 'dd.mm.yyyy',
            firstDay: 1
        }
    };

    $.fn[pluginName] = function ( options ) {
        if (Datepicker.prototype[options]) {
            Datepicker.prototype[options].apply(this.data(pluginName), Array.prototype.slice.call(arguments, 1));
        } else {
            return this.each(function () {
                if (!$.data(this, pluginName)) {
                    $.data(this,  pluginName,
                        new Datepicker( this, options ));
                } else {
                    var _this = $.data(this, pluginName),
                        oldOpts = _this.opts;

                    _this.opts = $.extend({}, oldOpts, options);
                }
            });
        }
    };

})(window, jQuery);