;(function () {
    var template = '' +
        '<div class="datepicker--nav-action" data-action="prev">#{prevHtml}</div>' +
        '<div class="datepicker--nav-title">#{title}</div>' +
        '<div class="datepicker--nav-action" data-action="next">#{nextHtml}</div>',
        buttonsContainerTemplate = '<div class="datepicker--buttons"></div>',
        button = '<span class="datepicker--button" data-action="#{action}">#{label}</span>',
        datepicker = $.fn.datepicker,
        dp = datepicker.Constructor;

    datepicker.Navigation = function (d, opts) {
        this.d = d;
        this.opts = opts;

        this.$buttonsContainer = '';

        this.init();
    };

    datepicker.Navigation.prototype = {
        init: function () {
            this._buildBaseHtml();
            this._bindEvents();
        },

        _bindEvents: function () {
            this.d.$nav.on('click', '.datepicker--nav-action', $.proxy(this._onClickNavButton, this));
            this.d.$nav.on('click', '.datepicker--nav-title', $.proxy(this._onClickNavTitle, this));
            this.d.$datepicker.on('click', '.datepicker--button', $.proxy(this._onClickNavButton, this));
        },

        _buildBaseHtml: function () {
            if (!this.opts.onlyTimepicker) {
                this._render();
            }
            this._addButtonsIfNeed();
        },

        _addButtonsIfNeed: function () {
            if (this.opts.todayButton) {
                this._addButton('today')
            }
            if (this.opts.clearButton) {
                this._addButton('clear')
            }
        },

        _render: function () {
            var title = this._getTitle(this.d.currentDate),
                html = dp.template(template, $.extend({title: title}, this.opts));
            this.d.$nav.html(html);
            if (this.d.view == 'years') {
                $('.datepicker--nav-title', this.d.$nav).addClass('-disabled-');
            }
            this.setNavStatus();
        },

        _getTitle: function (date) {
            return this.d.formatDate(this.opts.navTitles[this.d.view], date)
        },

        _addButton: function (type) {
            if (!this.$buttonsContainer.length) {
                this._addButtonsContainer();
            }

            var data = {
                    action: type,
                    label: this.d.loc[type]
                },
                html = dp.template(button, data);

            if ($('[data-action=' + type + ']', this.$buttonsContainer).length) return;
            this.$buttonsContainer.append(html);
        },

        _addButtonsContainer: function () {
            this.d.$datepicker.append(buttonsContainerTemplate);
            this.$buttonsContainer = $('.datepicker--buttons', this.d.$datepicker);
        },

        setNavStatus: function () {
            if (!(this.opts.minDate || this.opts.maxDate) || !this.opts.disableNavWhenOutOfRange) return;

            var date = this.d.parsedDate,
                m = date.month,
                y = date.year,
                d = date.date;

            switch (this.d.view) {
                case 'days':
                    if (!this.d._isInRange(new Date(y, m-1, 1), 'month')) {
                        this._disableNav('prev')
                    }
                    if (!this.d._isInRange(new Date(y, m+1, 1), 'month')) {
                        this._disableNav('next')
                    }
                    break;
                case 'months':
                    if (!this.d._isInRange(new Date(y-1, m, d), 'year')) {
                        this._disableNav('prev')
                    }
                    if (!this.d._isInRange(new Date(y+1, m, d), 'year')) {
                        this._disableNav('next')
                    }
                    break;
                case 'years':
                    var decade = dp.getDecade(this.d.date);
                    if (!this.d._isInRange(new Date(decade[0] - 1, 0, 1), 'year')) {
                        this._disableNav('prev')
                    }
                    if (!this.d._isInRange(new Date(decade[1] + 1, 0, 1), 'year')) {
                        this._disableNav('next')
                    }
                    break;
            }
        },

        _disableNav: function (nav) {
            $('[data-action="' + nav + '"]', this.d.$nav).addClass('-disabled-')
        },

        _activateNav: function (nav) {
            $('[data-action="' + nav + '"]', this.d.$nav).removeClass('-disabled-')
        },

        _onClickNavButton: function (e) {
            var $el = $(e.target).closest('[data-action]'),
                action = $el.data('action');

            this.d[action]();
        },

        _onClickNavTitle: function (e) {
            if ($(e.target).hasClass('-disabled-')) return;

            if (this.d.view == 'days') {
                return this.d.view = 'months'
            }

            this.d.view = 'years';
        }
    }

})();