import ngModule from '../../module';
import Component from '../../lib/component';
import './style.scss';

/**
 * Flat calendar.
 *
 * @property {Array} data Array of events
 * @property {Function} hasEvents Determines if an events exists for a day
 * @property {Function} getClass Class to apply to specific day
 */
export default class Calendar extends Component {
    constructor($element, $scope) {
        super($element, $scope);
        this.events = [];
        this.defaultDate = new Date();
        this.displayControls = true;
        this.disabled = false;
        this.skip = 1;

        this.window.addEventListener('resize', () => {
            this.checkSize();
        });
    }

    /**
     * Resizes the calendar
     * based on component height
     */
    checkSize() {
        const height = this.$element[0].clientHeight;

        if (height < 530)
            this.$element.addClass('small');
        else
            this.$element.removeClass('small');
    }

    /**
     * Returns the initial date
     *
     * @return {Date} - Default date
     */
    get defaultDate() {
        return this._defaultDate;
    }

    /**
     * Sets a new initial date
     *
     * @param {Date} value - New default date
     */
    set defaultDate(value) {
        if (value) {
            value = new Date(value);
            value.setHours(0, 0, 0, 0);
            value.setDate(1);
        }

        this._defaultDate = value;
        this.repaint();
    }

    /**
     * Sets events
     *
     * @param {Array} value - Array of events
     * @param {Date} event.dated - Day to add event
     * @param {String} event.name - Tooltip description
     * @param {String} event.className - ClassName style
     * @param {Object} event.style - Style properties
     */
    set data(value) {
        if (!value) return;

        this.events = [];

        value.forEach(event => {
            event.dated = new Date(event.dated);
            event.dated.setHours(0, 0, 0, 0);
            this.events.push(event);
        });

        if (this.defaultDate) {
            this.repaint();
            this.checkSize();
        }
    }

    /**
     * Gets current month date
     */

    get currentMonth() {
        return this.defaultDate;
    }

    /**
     * Gets next month date
     *
     * @return {Date}
     */
    get nextMonth() {
        const newDate = new Date(this.currentMonth);
        newDate.setMonth(this.currentMonth.getMonth() + 1);

        return newDate;
    }

    /**
     * Gets previous month date
     *
     * @return {Date}
     */
    get previousMonth() {
        const newDate = new Date(this.currentMonth);
        newDate.setMonth(this.currentMonth.getMonth() - 1);

        return newDate;
    }

    /**
     * Returns first day of month from a given date
     *
     * @param {Date} date - Origin date
     * @return {Integer}
     */
    firstDay(date) {
        const newDate = new Date(
            date.getFullYear(),
            date.getMonth(), 1);

        return newDate;
    }

    /**
     * Returns last day of month from a given date
     *
     * @param {Date} date - Origin date
     * @return {Integer}
     */
    lastDay(date) {
        const newDate = new Date(
            date.getFullYear(),
            date.getMonth() + 1, 0);

        return newDate;
    }

    repaint() {
        const firstWeekday = this.firstDay(this.currentMonth).getDay();
        const previousLastDay = this.lastDay(this.previousMonth).getDate();
        const currentLastDay = this.lastDay(this.currentMonth).getDate();
        const maxFields = 42; // Max field limit

        let weekdayOffset = firstWeekday > 0 ? firstWeekday : 7;
        let dayPrevious = previousLastDay - (weekdayOffset - 2);
        let dayCurrent = 1;
        let dayNext = 1;

        this.days = [];

        for (let fieldIndex = 1; fieldIndex < maxFields; fieldIndex++) {
            // Insert previous month days
            if (fieldIndex < weekdayOffset) {
                const dated = new Date(
                    this.previousMonth.getFullYear(),
                    this.previousMonth.getMonth(), dayPrevious);

                this.insertDay(dated, 'gray');
                dayPrevious++;
            }

            // Insert current month days
            if (fieldIndex >= weekdayOffset && dayCurrent <= currentLastDay) {
                const dated = new Date(
                    this.currentMonth.getFullYear(),
                    this.currentMonth.getMonth(), dayCurrent);

                this.insertDay(dated);
                dayCurrent++;
            }

            // Insert next month days
            if (fieldIndex >= weekdayOffset && dayCurrent > currentLastDay) {
                const dated = new Date(
                    this.nextMonth.getFullYear(),
                    this.nextMonth.getMonth(), dayNext);

                this.insertDay(dated, 'gray');
                dayNext++;
            }
        }
    }

    /**
     * Inserts a date on an array of month days
     *
     * @param {Date} dated - Date of month
     * @param {String} className - Default class style
     */
    insertDay(dated) {
        let events = this.events.filter(event => {
            return event.dated >= dated && event.dated <= dated;
        });

        const params = {dated: dated, events: events, style: {}};
        const isSaturday = dated.getDay() === 6;
        const isSunday = dated.getDay() === 0;
        const isCurrentMonth = dated.getMonth() === this.currentMonth.getMonth();
        const hasEvents = events.length > 0;

        if (isCurrentMonth && isSunday && !hasEvents)
            params.style = {color: '#999'};

        if (isCurrentMonth && isSaturday && !hasEvents)
            params.style = {color: '#999'};

        if (!isCurrentMonth)
            params.style = {opacity: '0.5'};

        if (events.length > 0) {
            const eventStyle = events[0].style;
            const eventName = events[0].description || events[0].name;
            if (eventStyle)
                Object.assign(params.style, eventStyle);
            if (eventName)
                params.eventName = eventName;
        }

        this.days.push(params);
    }

    /**
     * Moves to next month(s)
     *
     * @param {Integer} skip - Months to skip at once
     */
    moveNext(skip = 1) {
        let next = this.defaultDate.getMonth() + skip;
        this.defaultDate.setMonth(next);
        this.repaint();
        this.emit('moveNext');
    }

    /**
     * Moves to previous month(s)
     *
     * @param {Integer} skip - Months to skip at once
     */
    movePrevious(skip = 1) {
        let previous = this.defaultDate.getMonth() - skip;
        this.defaultDate.setMonth(previous);
        this.repaint();
        this.emit('movePrevious');
    }

    /**
     * Day selection event
     *
     * @param {Integer} index - Index from days array
     */
    select(index) {
        if (this.disabled) return;
        let day = this.days[index];
        day.index = index;

        this.emit('selection', {values: [day]});
    }

    /**
     * WeekDay selection event
     *
     * @param {Integer} weekday - weekday index
     */
    selectAll(weekday) {
        if (this.disabled) return;

        let selected = [];
        for (let i in this.days) {
            const day = this.days[i];
            const date = day.dated;
            day.index = i;
            if (date.getDay() === weekday && date.getMonth() == this.defaultDate.getMonth())
                selected.push(day);
        }
        this.emit('selection', {values: selected});
    }

    renderStyle(style) {
        const normalizedStyle = {};

        const properties = Object.keys(style);
        properties.forEach(attribute => {
            const attrName = attribute.split(/(?=[A-Z])/).
                join('-').toLowerCase();

            normalizedStyle[attrName] = style[attribute];
        });

        return normalizedStyle;
    }

    hasEvents() {
        return false;
    }

    getClass() {
        return '';
    }
}

Calendar.$inject = ['$element', '$scope'];

ngModule.component('vnCalendar', {
    template: require('./index.html'),
    controller: Calendar,
    bindings: {
        model: '<',
        data: '<?',
        defaultDate: '=?',
        onSelection: '&?',
        onMoveNext: '&?',
        onMovePrevious: '&?',
        hasEvents: '&?',
        getClass: '&?',
        displayControls: '<?',
        disabled: '<?',
        skip: '<?'
    }
});