import {ExComponent} from '../ExComponent.js'
import {Attribute, Component, Element, Renders} from '../decorators.js'

export interface NavBarItem {
    title: string,
    name: string,
    href?: string,
    right?: boolean,
}

@Component('ex-nav')
export class NavBarComponent extends ExComponent {
    protected static styles = `
        <style>
            nav {
                display: flex;
                flex-direction: row;
                margin-top: 50px;
                margin-bottom: 20px;
            }

            ul {
                flex: 1;
                list-style-type: none;
                margin: 0;
                padding: 0;
                overflow: hidden;
            }

            li {
                float: left;
            }

            li.right {
                float: right;
            }

            li:hover {
                background: var(--color-background-darkened);
            }

            li a {
                display: block;
                text-align: center;
                padding: 16px 10px;
                text-decoration: none;
                color: var(--color-accent-text);
            }

            li a:visited {
                color: var(--color-accent-text);
            }

            span {
                font-size: 1.2em;
                font-weight: bold;
                padding: 14px;
                padding-right: 30px;
                padding-left: 0;
            }

            .items-container {
                display: none;
            }
        </style>
    `

    protected static html = `
        <nav>
            <slot name="branding"></slot>
            <span class="appName"></span>
            <ul></ul>
        </nav>
        <div class="items-container">
            <slot></slot>
        </div>
    `

    @Renders()
    public items: NavBarItem[] = []

    @Attribute()
    public appName = ''

    @Element('span.appName')
    protected appNameEl!: HTMLSpanElement

    @Element('ul')
    protected list!: HTMLUListElement

    render() {
        super.render()

        this.appNameEl.hidden = !this.appName
        this.appNameEl.innerText = this.appName || ''

        this.list.childNodes.forEach(x => x.remove())
        for ( const item of this.getItems() ) {
            const li = document.createElement('li')
            const a = document.createElement('a')
            li.appendChild(a)

            a.setAttribute('href', item.href ?? '#')
            a.innerText = item.title
            a.addEventListener('click', () => this.dispatchItemClick(item.name))

            if ( item.right ) {
                li.classList.add('right')
            }

            this.list.append(li)
        }
    }

    getItems(): NavBarItem[] {
        const itemEls = this.querySelectorAll('ex-nav-item').values()
        const items = []

        for ( const itemEl of itemEls ) {
            const title = itemEl.getAttribute('title')
            const name = itemEl.getAttribute('name')
            if ( title && name ) {
                const item: NavBarItem = {
                    title,
                    name,
                    right: itemEl.hasAttribute('right'),
                }

                const href = itemEl.getAttribute('href')
                if ( href ) {
                    item.href = href
                }

                items.push(item)
            }
        }

        return items
    }

    dispatchItemClick(name: string) {
        return this.dispatchCustom('onItemClick', { name })
    }
}