import { append, setStyles, setStyle, insertByIndex } from './utils';

let id = 0;
export default class Layers {
    constructor(art) {
        id = 0;
        this.art = art;
        this.add = this.add.bind(this);
        this.art.option.layers.forEach(item => {
            this.add(item);
        });
    }

    add(item, callback) {
        const layer = typeof item === 'function' ? item(this.art) : item;
        if (!layer.disable) {
            id += 1;
            const {
                refs: { $layers },
                events: { proxy },
            } = this.art;
            const name = layer.name || `layer${id}`;
            const $layer = document.createElement('div');
            $layer.classList.value = `art-layer art-layer-${name}`;
            setStyles($layer, layer.style || {});
            append($layer, layer.html);
            if (layer.click) {
                proxy($layer, 'click', event => {
                    event.preventDefault();
                    layer.click.call(this, event);
                    this.art.emit('layers:click', $layer);
                });
            }
            insertByIndex($layers, $layer, layer.index || id);
            this[name] = $layer;
            if (item.callback) {
                item.callback($layer);
            }
            if (callback) {
                callback($layer);
            }
            this.art.emit('layers:add', $layer);
        }
    }

    show() {
        const { $layers } = this.art.refs;
        setStyle($layers, 'display', 'block');
        this.art.emit('layers:show', $layers);
    }

    hide() {
        const { $layers } = this.art.refs;
        setStyle($layers, 'display', 'none');
        this.art.emit('layers:hide', $layers);
    }
}