// @flow
import { helpers } from 'utils';
import LayoutBehavior from './behaviors/LayoutBehavior';
import Marionette from 'backbone.marionette';

const classes = {
    CLASS_NAME: 'layout__vertical-layout',
    ITEM: 'layout__vertical-layout-item',
    HIDDEN: 'layout__hidden'
};

export default Marionette.View.extend({
    initialize(options) {
        helpers.ensureOption(options, 'rows');

        this.rows = options.rows;
    },

    tagName: 'div',

    template: _.noop,

    className() {
        return `${classes.CLASS_NAME} ${this.options.class || ''}`;
    },

    behaviors: {
        LayoutBehavior: {
            behaviorClass: LayoutBehavior
        }
    },

    templateContext() {
        return {
            title: this.options.title
        };
    },

    onRender() {
        this.__rowsCtx = [];
        this.rows.forEach(view => {
            view.on('change:visible', (activeView, visible) => this.__handleChangeVisibility(activeView, visible));

            this.$el.append(view.render().$el);
            this.__rowsCtx.push({
                view
            });
        });
        this.__updateState();
    },

    onAttach() {
        this.rows.forEach(view => {
            view._isAttached = true;
            view.triggerMethod('before:attach');
            view.triggerMethod('attach');
        });
    },

    update() {
        this.rows.forEach(view => {
            if (view.update) {
                view.update();
            }
        });
        this.__updateState();
    },

    validate() {
        let result;
        this.rows.forEach(view => {
            if (view.validate) {
                const error = view.validate();
                if (error) {
                    result = error;
                }
            }
        });
        return result;
    },

    __handleChangeVisibility(view, visible) {
        view.$el.toggleClass(classes.HIDDEN, !visible);
    },

    onDestroy() {
        this.rows.forEach(view => view.destroy());
    }
});