/**
 * <folk-widget> — Widget shell for rApp canvas surfaces.
 *
 * Provides a consistent title bar (icon + label + controls) and a slotted body.
 * Used inside <folk-app-canvas> to wrap feature views as togglable overlays.
 *
 * Attributes:
 *   widget-id  — unique id within the canvas (used for layout + toolbar state)
 *   title      — display label
 *   icon       — emoji/glyph shown in title bar
 *   grid-area  — optional CSS grid-area (for grid-mode canvas)
 *   minimized  — boolean; collapses body
 *   no-close   — hides the close button
 *
 * Events:
 *   widget-close     — user clicked ×
 *   widget-minimize  — user toggled –
 *   widget-focus     — user clicked header (for z-stacking / detail panels)
 */

class FolkWidget extends HTMLElement {
	static get observedAttributes() {
		return ['title', 'icon', 'minimized', 'grid-area'];
	}

	private shadow: ShadowRoot;
	private _rendered = false;

	constructor() {
		super();
		this.shadow = this.attachShadow({ mode: 'open' });
	}

	connectedCallback() {
		if (!this._rendered) {
			this.render();
			this._rendered = true;
		}
		this.applyGridArea();
	}

	attributeChangedCallback(name: string) {
		if (!this._rendered) return;
		if (name === 'title' || name === 'icon') {
			this.updateHeader();
		} else if (name === 'minimized') {
			this.updateMinimized();
		} else if (name === 'grid-area') {
			this.applyGridArea();
		}
	}

	private applyGridArea() {
		const area = this.getAttribute('grid-area');
		if (area) this.style.gridArea = area;
	}

	private render() {
		this.shadow.innerHTML = `
		<style>${this.getStyles()}</style>
		<div class="widget" part="widget">
			<header class="header" part="header">
				<div class="title">
					<span class="icon" part="icon">${this.esc(this.getAttribute('icon') || '')}</span>
					<span class="label" part="label">${this.esc(this.getAttribute('title') || 'Widget')}</span>
				</div>
				<div class="controls">
					<button class="ctl" data-action="minimize" title="Minimize" aria-label="Minimize">–</button>
					${this.hasAttribute('no-close') ? '' : `<button class="ctl" data-action="close" title="Close" aria-label="Close">×</button>`}
				</div>
			</header>
			<div class="body" part="body">
				<slot></slot>
			</div>
		</div>`;
		this.bindEvents();
		this.updateMinimized();
	}

	private updateHeader() {
		const icon = this.shadow.querySelector('.icon');
		const label = this.shadow.querySelector('.label');
		if (icon) icon.textContent = this.getAttribute('icon') || '';
		if (label) label.textContent = this.getAttribute('title') || 'Widget';
	}

	private updateMinimized() {
		const w = this.shadow.querySelector('.widget');
		if (!w) return;
		w.classList.toggle('minimized', this.hasAttribute('minimized'));
	}

	private bindEvents() {
		const header = this.shadow.querySelector('.header');
		header?.addEventListener('click', (e) => {
			const target = e.target as HTMLElement;
			if (target.closest('.controls')) return;
			this.dispatchEvent(new CustomEvent('widget-focus', { bubbles: true, composed: true, detail: { widgetId: this.getAttribute('widget-id') } }));
		});
		this.shadow.querySelector('[data-action="minimize"]')?.addEventListener('click', (e) => {
			e.stopPropagation();
			const mini = this.hasAttribute('minimized');
			if (mini) this.removeAttribute('minimized'); else this.setAttribute('minimized', '');
			this.dispatchEvent(new CustomEvent('widget-minimize', { bubbles: true, composed: true, detail: { widgetId: this.getAttribute('widget-id'), minimized: !mini } }));
		});
		this.shadow.querySelector('[data-action="close"]')?.addEventListener('click', (e) => {
			e.stopPropagation();
			this.dispatchEvent(new CustomEvent('widget-close', { bubbles: true, composed: true, detail: { widgetId: this.getAttribute('widget-id') } }));
		});
	}

	private getStyles(): string {
		return `
			:host { display: block; min-width: 0; min-height: 0; }
			.widget {
				display: flex; flex-direction: column;
				height: 100%; width: 100%;
				background: var(--rs-bg-surface);
				border: 1px solid var(--rs-border);
				border-radius: 10px;
				box-shadow: 0 2px 8px rgba(0,0,0,0.15);
				overflow: hidden;
			}
			.header {
				display: flex; align-items: center; justify-content: space-between;
				padding: 0.5rem 0.75rem;
				background: var(--rs-bg-surface-raised, var(--rs-bg-hover));
				border-bottom: 1px solid var(--rs-border);
				cursor: pointer;
				user-select: none;
				flex-shrink: 0;
			}
			.title { display: flex; align-items: center; gap: 0.5rem; min-width: 0; }
			.icon { font-size: 1rem; flex-shrink: 0; }
			.label { font-size: 0.8125rem; font-weight: 600; color: var(--rs-text-primary); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
			.controls { display: flex; gap: 0.125rem; flex-shrink: 0; }
			.ctl {
				background: transparent; border: none; color: var(--rs-text-secondary);
				cursor: pointer; padding: 0.125rem 0.5rem; border-radius: 4px;
				font-size: 1rem; line-height: 1; font-weight: 500;
			}
			.ctl:hover { background: var(--rs-bg-hover); color: var(--rs-text-primary); }
			.body { flex: 1; min-height: 0; overflow: auto; display: flex; flex-direction: column; }
			.body > ::slotted(*) { flex: 1; min-height: 0; }
			.widget.minimized .body { display: none; }
			.widget.minimized { height: auto !important; }
		`;
	}

	private esc(s: string): string {
		const d = document.createElement('div');
		d.textContent = s;
		return d.innerHTML;
	}
}

if (!customElements.get('folk-widget')) customElements.define('folk-widget', FolkWidget);

export {};