import { FolkShape } from "./folk-shape";
import { css, html } from "./tags";

const styles = css`
	:host {
		background: var(--rs-bg-surface, #fff);
		color: var(--rs-text-primary, #1e293b);
		border-radius: 8px;
		box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
		min-width: 520px;
		min-height: 480px;
	}

	.header {
		display: flex;
		align-items: center;
		justify-content: space-between;
		padding: 8px 12px;
		background: linear-gradient(135deg, #f97316, #eab308);
		color: white;
		border-radius: 8px 8px 0 0;
		font-size: 12px;
		font-weight: 600;
		cursor: move;
	}

	.header-title {
		display: flex;
		align-items: center;
		gap: 6px;
	}

	.header-actions {
		display: flex;
		gap: 4px;
	}

	.header-actions button {
		background: transparent;
		border: none;
		color: white;
		cursor: pointer;
		padding: 2px 6px;
		border-radius: 4px;
		font-size: 14px;
	}

	.header-actions button:hover {
		background: rgba(255, 255, 255, 0.2);
	}

	.content {
		display: flex;
		flex-direction: column;
		height: calc(100% - 36px);
		overflow: hidden;
	}

	.toolbar-row {
		display: flex;
		align-items: center;
		gap: 6px;
		padding: 8px 12px;
		border-bottom: 1px solid var(--rs-border, rgba(255, 255, 255, 0.1));
		flex-wrap: wrap;
	}

	.tool-btn {
		width: 32px;
		height: 32px;
		display: flex;
		align-items: center;
		justify-content: center;
		border: 2px solid var(--rs-border, rgba(255, 255, 255, 0.1));
		border-radius: 6px;
		background: var(--rs-bg-surface, #1e293b);
		cursor: pointer;
		font-size: 14px;
		transition: all 0.15s;
	}

	.tool-btn:hover {
		border-color: #f97316;
	}

	.tool-btn.active {
		border-color: #f97316;
		background: rgba(249, 115, 22, 0.15);
	}

	.color-swatch {
		width: 24px;
		height: 24px;
		border-radius: 50%;
		border: 2px solid var(--rs-border, rgba(255, 255, 255, 0.1));
		cursor: pointer;
		transition: transform 0.1s;
	}

	.color-swatch:hover {
		transform: scale(1.2);
	}

	.color-swatch.active {
		border-color: var(--rs-text-primary, #e2e8f0);
		transform: scale(1.15);
	}

	.size-slider {
		width: 80px;
		accent-color: #f97316;
	}

	.size-label {
		font-size: 11px;
		color: var(--rs-text-muted, #64748b);
		min-width: 20px;
	}

	.split-area {
		flex: 1;
		display: flex;
		overflow: hidden;
		min-height: 0;
	}

	.canvas-area {
		flex: 1;
		position: relative;
		cursor: crosshair;
		overflow: hidden;
		min-width: 0;
	}

	.canvas-area canvas {
		width: 100%;
		height: 100%;
		display: block;
	}

	.result-area {
		flex: 1;
		position: relative;
		overflow: hidden;
		display: flex;
		align-items: center;
		justify-content: center;
		background: var(--rs-bg-muted, #f8fafc);
		border-left: 1px solid var(--rs-border, rgba(255, 255, 255, 0.1));
		min-width: 0;
	}

	.result-area img {
		max-width: 100%;
		max-height: 100%;
		object-fit: contain;
		border-radius: 4px;
		transition: opacity 0.2s ease-in-out;
	}

	.result-placeholder {
		display: flex;
		flex-direction: column;
		align-items: center;
		gap: 8px;
		color: var(--rs-text-muted, #94a3b8);
		text-align: center;
		font-size: 12px;
		padding: 12px;
	}

	.result-placeholder-icon {
		font-size: 32px;
		opacity: 0.4;
	}

	.spinner-overlay {
		position: absolute;
		inset: 0;
		display: flex;
		flex-direction: column;
		align-items: center;
		justify-content: center;
		background: rgba(255, 255, 255, 0.7);
		gap: 8px;
		z-index: 2;
	}

	.spinner {
		width: 28px;
		height: 28px;
		border: 3px solid #e2e8f0;
		border-top-color: #f97316;
		border-radius: 50%;
		animation: spin 1s linear infinite;
	}

	.spinner-text {
		font-size: 11px;
		color: #64748b;
	}

	@keyframes spin {
		to { transform: rotate(360deg); }
	}

	@keyframes shimmer {
		0% { background-position: 200% 0; }
		100% { background-position: -200% 0; }
	}

	.prompt-bar {
		display: flex;
		gap: 6px;
		padding: 8px 12px;
		border-top: 1px solid var(--rs-border, rgba(255, 255, 255, 0.1));
		align-items: center;
	}

	.prompt-input {
		flex: 1;
		padding: 6px 10px;
		border: 2px solid var(--rs-input-border, #e2e8f0);
		border-radius: 6px;
		font-size: 12px;
		outline: none;
		font-family: inherit;
		background: var(--rs-input-bg, #fff);
		color: var(--rs-input-text, inherit);
	}

	.prompt-input:focus {
		border-color: #f97316;
	}

	.generate-btn {
		padding: 6px 14px;
		background: linear-gradient(135deg, #f97316, #eab308);
		color: white;
		border: none;
		border-radius: 6px;
		font-size: 12px;
		font-weight: 600;
		cursor: pointer;
		white-space: nowrap;
		transition: opacity 0.2s;
	}

	.generate-btn:hover {
		opacity: 0.9;
	}

	.generate-btn:disabled {
		opacity: 0.5;
		cursor: not-allowed;
	}

	.prompt-controls {
		display: flex;
		gap: 6px;
		align-items: center;
	}

	.auto-toggle {
		display: flex;
		align-items: center;
		gap: 4px;
		font-size: 11px;
		color: var(--rs-text-muted, #64748b);
		cursor: pointer;
		user-select: none;
	}

	.auto-toggle input {
		accent-color: #f97316;
	}

	.provider-select {
		padding: 4px 8px;
		border: 2px solid #e2e8f0;
		border-radius: 6px;
		font-size: 11px;
		background: var(--rs-bg-surface, white);
		cursor: pointer;
	}

	.strength-slider {
		width: 60px;
		accent-color: #f97316;
	}

	.strength-label {
		font-size: 10px;
		color: var(--rs-text-muted, #64748b);
		min-width: 28px;
	}

	.export-btn {
		padding: 6px 12px;
		background: #f97316;
		color: white;
		border: none;
		border-radius: 6px;
		font-size: 12px;
		font-weight: 600;
		cursor: pointer;
	}

	.export-btn:hover {
		opacity: 0.9;
	}

	.gesture-badge {
		position: absolute;
		top: 8px;
		left: 50%;
		transform: translateX(-50%);
		background: rgba(249, 115, 22, 0.9);
		color: white;
		padding: 4px 12px;
		border-radius: 12px;
		font-size: 11px;
		font-weight: 600;
		z-index: 3;
		pointer-events: none;
		animation: badge-fade 1.5s ease-out forwards;
	}

	@keyframes badge-fade {
		0% { opacity: 1; transform: translateX(-50%) translateY(0); }
		70% { opacity: 1; }
		100% { opacity: 0; transform: translateX(-50%) translateY(-10px); }
	}
`;

const COLORS = ["#0f172a", "#ef4444", "#f97316", "#eab308", "#22c55e", "#3b82f6", "#8b5cf6", "#ec4899", "#ffffff"];

interface Stroke {
	points: { x: number; y: number; pressure: number }[];
	color: string;
	size: number;
	tool: string;
}

// --- $1 Unistroke Recognizer (lightweight, self-contained) ---
// Based on Wobbrock et al. 2007, adapted from canvas-website gesture templates

interface Point2D { x: number; y: number; }
interface RecognizeResult { name: string; score: number; }

const NUM_POINTS = 64;
const SQUARE_SIZE = 250;
const HALF_DIAGONAL = 0.5 * Math.sqrt(SQUARE_SIZE * SQUARE_SIZE + SQUARE_SIZE * SQUARE_SIZE);
const ANGLE_RANGE = Math.PI * 2;
const ANGLE_PRECISION = Math.PI / 90; // 2 degrees
const PHI = 0.5 * (-1 + Math.sqrt(5)); // golden ratio

function resample(pts: Point2D[], n: number): Point2D[] {
	const totalLen = pathLength(pts);
	const interval = totalLen / (n - 1);
	const newPts: Point2D[] = [pts[0]];
	let D = 0;
	for (let i = 1; i < pts.length; i++) {
		const d = distance(pts[i - 1], pts[i]);
		if (D + d >= interval) {
			const t = (interval - D) / d;
			const qx = pts[i - 1].x + t * (pts[i].x - pts[i - 1].x);
			const qy = pts[i - 1].y + t * (pts[i].y - pts[i - 1].y);
			const q: Point2D = { x: qx, y: qy };
			newPts.push(q);
			pts.splice(i, 0, q);
			D = 0;
		} else {
			D += d;
		}
	}
	while (newPts.length < n) newPts.push(pts[pts.length - 1]);
	return newPts;
}

function rotateToZero(pts: Point2D[]): Point2D[] {
	const c = centroid(pts);
	const angle = Math.atan2(c.y - pts[0].y, c.x - pts[0].x);
	return rotateBy(pts, -angle);
}

function scaleToSquare(pts: Point2D[]): Point2D[] {
	let minX = Infinity, maxX = -Infinity, minY = Infinity, maxY = -Infinity;
	for (const p of pts) {
		minX = Math.min(minX, p.x); maxX = Math.max(maxX, p.x);
		minY = Math.min(minY, p.y); maxY = Math.max(maxY, p.y);
	}
	const w = maxX - minX || 1;
	const h = maxY - minY || 1;
	return pts.map(p => ({ x: p.x * (SQUARE_SIZE / w), y: p.y * (SQUARE_SIZE / h) }));
}

function translateToOrigin(pts: Point2D[]): Point2D[] {
	const c = centroid(pts);
	return pts.map(p => ({ x: p.x - c.x, y: p.y - c.y }));
}

function recognize(pts: Point2D[], templates: { name: string; points: Point2D[] }[]): RecognizeResult {
	let best = Infinity;
	let bestName = "none";
	for (const t of templates) {
		const d = distanceAtBestAngle(pts, t.points, -ANGLE_RANGE, ANGLE_RANGE, ANGLE_PRECISION);
		if (d < best) {
			best = d;
			bestName = t.name;
		}
	}
	const score = 1 - best / HALF_DIAGONAL;
	return { name: bestName, score };
}

function distanceAtBestAngle(pts: Point2D[], template: Point2D[], a: number, b: number, threshold: number): number {
	let x1 = PHI * a + (1 - PHI) * b;
	let f1 = distanceAtAngle(pts, template, x1);
	let x2 = (1 - PHI) * a + PHI * b;
	let f2 = distanceAtAngle(pts, template, x2);
	while (Math.abs(b - a) > threshold) {
		if (f1 < f2) {
			b = x2; x2 = x1; f2 = f1;
			x1 = PHI * a + (1 - PHI) * b;
			f1 = distanceAtAngle(pts, template, x1);
		} else {
			a = x1; x1 = x2; f1 = f2;
			x2 = (1 - PHI) * a + PHI * b;
			f2 = distanceAtAngle(pts, template, x2);
		}
	}
	return Math.min(f1, f2);
}

function distanceAtAngle(pts: Point2D[], template: Point2D[], angle: number): number {
	const rotated = rotateBy(pts, angle);
	return pathDistance(rotated, template);
}

function centroid(pts: Point2D[]): Point2D {
	let x = 0, y = 0;
	for (const p of pts) { x += p.x; y += p.y; }
	return { x: x / pts.length, y: y / pts.length };
}

function rotateBy(pts: Point2D[], angle: number): Point2D[] {
	const c = centroid(pts);
	const cos = Math.cos(angle), sin = Math.sin(angle);
	return pts.map(p => ({
		x: (p.x - c.x) * cos - (p.y - c.y) * sin + c.x,
		y: (p.x - c.x) * sin + (p.y - c.y) * cos + c.y,
	}));
}

function pathDistance(a: Point2D[], b: Point2D[]): number {
	let d = 0;
	const n = Math.min(a.length, b.length);
	for (let i = 0; i < n; i++) d += distance(a[i], b[i]);
	return d / n;
}

function pathLength(pts: Point2D[]): number {
	let d = 0;
	for (let i = 1; i < pts.length; i++) d += distance(pts[i - 1], pts[i]);
	return d;
}

function distance(a: Point2D, b: Point2D): number {
	const dx = b.x - a.x, dy = b.y - a.y;
	return Math.sqrt(dx * dx + dy * dy);
}

function processTemplate(pts: Point2D[]): Point2D[] {
	return translateToOrigin(scaleToSquare(rotateToZero(resample(pts, NUM_POINTS))));
}

// Generate templates procedurally (more compact than storing point arrays)
function makeCircleTemplate(): Point2D[] {
	const pts: Point2D[] = [];
	for (let i = 0; i <= 32; i++) {
		const a = (i / 32) * Math.PI * 2;
		pts.push({ x: 100 + 80 * Math.cos(a), y: 100 + 80 * Math.sin(a) });
	}
	return processTemplate(pts);
}

function makeRectangleTemplate(): Point2D[] {
	const pts: Point2D[] = [];
	// Draw rectangle starting top-left, clockwise
	const steps = 8;
	for (let i = 0; i <= steps; i++) pts.push({ x: 20 + (160 * i / steps), y: 20 }); // top
	for (let i = 0; i <= steps; i++) pts.push({ x: 180, y: 20 + (160 * i / steps) }); // right
	for (let i = 0; i <= steps; i++) pts.push({ x: 180 - (160 * i / steps), y: 180 }); // bottom
	for (let i = 0; i <= steps; i++) pts.push({ x: 20, y: 180 - (160 * i / steps) }); // left
	return processTemplate(pts);
}

function makeLineTemplate(): Point2D[] {
	const pts: Point2D[] = [];
	for (let i = 0; i <= 16; i++) pts.push({ x: 20 + (160 * i / 16), y: 100 });
	return processTemplate(pts);
}

function makeArrowTemplate(): Point2D[] {
	// Horizontal line with arrowhead at the end
	const pts: Point2D[] = [];
	for (let i = 0; i <= 12; i++) pts.push({ x: 20 + (140 * i / 12), y: 100 }); // shaft
	for (let i = 0; i <= 4; i++) pts.push({ x: 160 - (40 * i / 4), y: 100 - (40 * i / 4) }); // upper head
	pts.push({ x: 160, y: 100 }); // back to tip
	for (let i = 0; i <= 4; i++) pts.push({ x: 160 - (40 * i / 4), y: 100 + (40 * i / 4) }); // lower head
	return processTemplate(pts);
}

function makeTriangleTemplate(): Point2D[] {
	const pts: Point2D[] = [];
	const steps = 8;
	// Top to bottom-right
	for (let i = 0; i <= steps; i++) pts.push({ x: 100 + (80 * i / steps), y: 20 + (160 * i / steps) });
	// Bottom-right to bottom-left
	for (let i = 0; i <= steps; i++) pts.push({ x: 180 - (160 * i / steps), y: 180 });
	// Bottom-left to top
	for (let i = 0; i <= steps; i++) pts.push({ x: 20 + (80 * i / steps), y: 180 - (160 * i / steps) });
	return processTemplate(pts);
}

function makeCheckTemplate(): Point2D[] {
	const pts: Point2D[] = [];
	for (let i = 0; i <= 6; i++) pts.push({ x: 20 + (40 * i / 6), y: 100 + (60 * i / 6) });
	for (let i = 0; i <= 8; i++) pts.push({ x: 60 + (120 * i / 8), y: 160 - (140 * i / 8) });
	return processTemplate(pts);
}

const GESTURE_TEMPLATES = [
	{ name: "circle", points: makeCircleTemplate() },
	{ name: "rectangle", points: makeRectangleTemplate() },
	{ name: "line", points: makeLineTemplate() },
	{ name: "arrow", points: makeArrowTemplate() },
	{ name: "triangle", points: makeTriangleTemplate() },
	{ name: "check", points: makeCheckTemplate() },
];

function recognizeGesture(rawPoints: Point2D[]): RecognizeResult | null {
	if (rawPoints.length < 8) return null; // too few points
	const processed = processTemplate(rawPoints);
	const result = recognize(processed, GESTURE_TEMPLATES);
	if (result.score < 0.7) return null; // low confidence
	return result;
}
// --- End $1 Unistroke Recognizer ---

declare global {
	interface HTMLElementTagNameMap {
		"folk-drawfast": FolkDrawfast;
	}
}

export class FolkDrawfast extends FolkShape {
	static override tagName = "folk-drawfast";

	static override portDescriptors = [
		{ name: "prompt", type: "text" as const, direction: "input" as const },
		{ name: "sketch", type: "image-url" as const, direction: "output" as const },
		{ name: "image", type: "image-url" as const, direction: "output" as const },
	];

	static {
		const sheet = new CSSStyleSheet();
		const parentRules = Array.from(FolkShape.styles.cssRules)
			.map((r) => r.cssText)
			.join("\n");
		const childRules = Array.from(styles.cssRules)
			.map((r) => r.cssText)
			.join("\n");
		sheet.replaceSync(`${parentRules}\n${childRules}`);
		this.styles = sheet;
	}

	#strokes: Stroke[] = [];
	#currentStroke: Stroke | null = null;
	#canvas: HTMLCanvasElement | null = null;
	#ctx: CanvasRenderingContext2D | null = null;
	#color = "#0f172a";
	#brushSize = 4;
	#tool = "pen"; // pen | eraser
	#isDrawing = false;
	#isGenerating = false;
	#autoGenerate = false;
	#autoDebounceTimer: ReturnType<typeof setTimeout> | null = null;
	#provider: "fal" | "gemini" = "fal";
	#strength = 0.65;
	#lastResultUrl: string | null = null;
	#promptInput: HTMLInputElement | null = null;
	#generateBtn: HTMLButtonElement | null = null;
	#resultArea: HTMLElement | null = null;
	#canvasArea: HTMLElement | null = null;
	#gestureEnabled = true;

	get strokes() {
		return this.#strokes;
	}

	override createRenderRoot() {
		const root = super.createRenderRoot();

		const wrapper = document.createElement("div");
		wrapper.innerHTML = html`
			<div class="header">
				<span class="header-title">
					<span>✏️</span>
					<span>Drawfast AI</span>
				</span>
				<div class="header-actions">
					<button class="export-png-btn" title="Export PNG">💾</button>
					<button class="close-btn" title="Close">×</button>
				</div>
			</div>
			<div class="content">
				<div class="toolbar-row">
					<button class="tool-btn active" data-tool="pen" title="Pen">✏️</button>
					<button class="tool-btn" data-tool="eraser" title="Eraser">🧹</button>
					<span style="width:1px;height:20px;background:var(--rs-border,rgba(255,255,255,0.1));margin:0 2px"></span>
					${COLORS.map((c) => `<span class="color-swatch${c === "#0f172a" ? " active" : ""}" data-color="${c}" style="background:${c}"></span>`).join("")}
					<span style="width:1px;height:20px;background:var(--rs-border,rgba(255,255,255,0.1));margin:0 2px"></span>
					<input type="range" class="size-slider" min="1" max="24" value="4" />
					<span class="size-label">4</span>
					<span style="flex:1"></span>
					<button class="tool-btn" data-tool="clear" title="Clear all">🗑️</button>
				</div>
				<div class="split-area">
					<div class="canvas-area">
						<canvas></canvas>
					</div>
					<div class="result-area">
						<div class="result-placeholder">
							<span class="result-placeholder-icon">🎨</span>
							<span>Draw a sketch and click Generate</span>
						</div>
					</div>
				</div>
				<div class="prompt-bar">
					<input type="text" class="prompt-input" placeholder="Describe what to generate from your sketch..." />
					<div class="prompt-controls">
						<label class="auto-toggle" title="Auto-generate after each stroke">
							<input type="checkbox" class="auto-checkbox" />
							Auto
						</label>
						<select class="provider-select">
							<option value="fal">fal.ai</option>
							<option value="gemini">Gemini</option>
						</select>
						<input type="range" class="strength-slider" min="30" max="95" value="65" title="AI strength" />
						<span class="strength-label">65%</span>
					</div>
					<button class="generate-btn">Generate</button>
				</div>
			</div>
		`;

		const slot = root.querySelector("slot");
		const containerDiv = slot?.parentElement as HTMLElement;
		if (containerDiv) {
			containerDiv.replaceWith(wrapper);
		}

		this.#canvas = wrapper.querySelector(".canvas-area canvas") as HTMLCanvasElement;
		this.#ctx = this.#canvas.getContext("2d");
		this.#promptInput = wrapper.querySelector(".prompt-input") as HTMLInputElement;
		this.#generateBtn = wrapper.querySelector(".generate-btn") as HTMLButtonElement;
		this.#resultArea = wrapper.querySelector(".result-area") as HTMLElement;

		const closeBtn = wrapper.querySelector(".close-btn") as HTMLButtonElement;
		const exportBtn = wrapper.querySelector(".export-png-btn") as HTMLButtonElement;
		const sizeSlider = wrapper.querySelector(".size-slider") as HTMLInputElement;
		const sizeLabel = wrapper.querySelector(".size-label") as HTMLElement;
		const canvasArea = wrapper.querySelector(".canvas-area") as HTMLElement;
		this.#canvasArea = canvasArea;
		const autoCheckbox = wrapper.querySelector(".auto-checkbox") as HTMLInputElement;
		const providerSelect = wrapper.querySelector(".provider-select") as HTMLSelectElement;
		const strengthSlider = wrapper.querySelector(".strength-slider") as HTMLInputElement;
		const strengthLabel = wrapper.querySelector(".strength-label") as HTMLElement;

		// Tool buttons
		wrapper.querySelectorAll(".tool-btn").forEach((btn) => {
			btn.addEventListener("click", (e) => {
				e.stopPropagation();
				const tool = (btn as HTMLElement).dataset.tool;
				if (tool === "clear") {
					this.#strokes = [];
					this.#redraw();
					return;
				}
				this.#tool = tool || "pen";
				wrapper.querySelectorAll(".tool-btn").forEach((b) => b.classList.remove("active"));
				if (tool !== "clear") btn.classList.add("active");
			});
		});

		// Color swatches
		wrapper.querySelectorAll(".color-swatch").forEach((swatch) => {
			swatch.addEventListener("click", (e) => {
				e.stopPropagation();
				this.#color = (swatch as HTMLElement).dataset.color || "#0f172a";
				wrapper.querySelectorAll(".color-swatch").forEach((s) => s.classList.remove("active"));
				swatch.classList.add("active");
				this.#tool = "pen";
				wrapper.querySelectorAll(".tool-btn").forEach((b) => b.classList.remove("active"));
				wrapper.querySelector('[data-tool="pen"]')?.classList.add("active");
			});
		});

		// Size slider
		sizeSlider.addEventListener("input", (e) => {
			e.stopPropagation();
			this.#brushSize = parseInt(sizeSlider.value);
			sizeLabel.textContent = sizeSlider.value;
		});
		sizeSlider.addEventListener("pointerdown", (e) => e.stopPropagation());

		// Strength slider
		strengthSlider.addEventListener("input", (e) => {
			e.stopPropagation();
			this.#strength = parseInt(strengthSlider.value) / 100;
			strengthLabel.textContent = strengthSlider.value + "%";
		});
		strengthSlider.addEventListener("pointerdown", (e) => e.stopPropagation());

		// Auto-generate toggle
		autoCheckbox.addEventListener("change", (e) => {
			e.stopPropagation();
			this.#autoGenerate = autoCheckbox.checked;
		});

		// Provider select
		providerSelect.addEventListener("change", (e) => {
			e.stopPropagation();
			this.#provider = providerSelect.value as "fal" | "gemini";
		});
		providerSelect.addEventListener("pointerdown", (e) => e.stopPropagation());

		// Drawing events
		this.#canvas.addEventListener("pointerdown", (e) => {
			e.stopPropagation();
			e.preventDefault();
			this.#isDrawing = true;
			this.#canvas!.setPointerCapture(e.pointerId);
			const pos = this.#getCanvasPos(e);
			this.#currentStroke = {
				points: [{ ...pos, pressure: e.pressure || 0.5 }],
				color: this.#tool === "eraser" ? "#ffffff" : this.#color,
				size: this.#tool === "eraser" ? this.#brushSize * 3 : this.#brushSize,
				tool: this.#tool,
			};
		});

		this.#canvas.addEventListener("pointermove", (e) => {
			if (!this.#isDrawing || !this.#currentStroke) return;
			e.stopPropagation();
			const pos = this.#getCanvasPos(e);
			this.#currentStroke.points.push({ ...pos, pressure: e.pressure || 0.5 });
			this.#drawStroke(this.#currentStroke);
		});

		const endDraw = (e: PointerEvent) => {
			if (!this.#isDrawing) return;
			this.#isDrawing = false;
			if (this.#currentStroke && this.#currentStroke.points.length > 0) {
				// Try gesture recognition before adding stroke
				let gestureResult: RecognizeResult | null = null;
				if (this.#gestureEnabled && this.#currentStroke.tool === "pen") {
					const rawPts = this.#currentStroke.points.map(p => ({ x: p.x, y: p.y }));
					gestureResult = recognizeGesture(rawPts);
				}

				if (gestureResult) {
					// Replace freehand stroke with clean geometric shape
					const cleanStroke = this.#makeCleanShape(gestureResult.name, this.#currentStroke);
					this.#strokes.push(cleanStroke);
					this.#redraw();
					this.#showGestureBadge(gestureResult.name, gestureResult.score);
					this.dispatchEvent(new CustomEvent("stroke-complete", {
						detail: { stroke: cleanStroke, gesture: gestureResult.name },
					}));
				} else {
					this.#strokes.push(this.#currentStroke);
					this.dispatchEvent(new CustomEvent("stroke-complete", {
						detail: { stroke: this.#currentStroke },
					}));
				}

				// Auto-generate on stroke complete if enabled
				if (this.#autoGenerate && this.#promptInput?.value.trim()) {
					this.#scheduleAutoGenerate();
				}
			}
			this.#currentStroke = null;
		};

		this.#canvas.addEventListener("pointerup", endDraw);
		this.#canvas.addEventListener("pointerleave", endDraw);

		// Generate button
		this.#generateBtn.addEventListener("click", (e) => {
			e.stopPropagation();
			this.#generate();
		});

		// Enter key in prompt
		this.#promptInput.addEventListener("keydown", (e) => {
			if (e.key === "Enter") {
				e.preventDefault();
				this.#generate();
			}
		});
		this.#promptInput.addEventListener("pointerdown", (e) => e.stopPropagation());

		// Export
		exportBtn.addEventListener("click", (e) => {
			e.stopPropagation();
			this.#exportPNG();
		});

		closeBtn.addEventListener("click", (e) => {
			e.stopPropagation();
			this.dispatchEvent(new CustomEvent("close"));
		});

		// Size canvas on next frame
		requestAnimationFrame(() => {
			this.#resizeCanvas(canvasArea);
			this.#redraw();
		});

		// Watch for resize
		const ro = new ResizeObserver(() => {
			this.#resizeCanvas(canvasArea);
			this.#redraw();
		});
		ro.observe(canvasArea);

		return root;
	}

	#scheduleAutoGenerate() {
		if (this.#autoDebounceTimer) clearTimeout(this.#autoDebounceTimer);
		this.#autoDebounceTimer = setTimeout(() => {
			this.#autoDebounceTimer = null;
			if (!this.#isGenerating) {
				this.#generate();
			}
		}, 500);
	}

	async #generate() {
		const prompt = this.#promptInput?.value.trim();
		if (!prompt || this.#isGenerating || !this.#canvas) return;

		this.#isGenerating = true;
		if (this.#generateBtn) this.#generateBtn.disabled = true;
		this.#renderLoading();

		try {
			const sourceImage = this.#canvas.toDataURL("image/jpeg", 0.8);

			const response = await fetch("/api/image-gen/img2img", {
				method: "POST",
				headers: { "Content-Type": "application/json" },
				body: JSON.stringify({
					prompt,
					source_image: sourceImage,
					provider: this.#provider,
					strength: this.#strength,
				}),
			});

			if (!response.ok) {
				throw new Error(`Generation failed: ${response.statusText}`);
			}

			const result = await response.json();
			const imageUrl = result.url || result.image_url;
			if (!imageUrl) throw new Error("No image returned");

			// Preload image before displaying
			await this.#preloadImage(imageUrl);

			this.#lastResultUrl = imageUrl;
			this.#renderResult(imageUrl, prompt);

			this.dispatchEvent(new CustomEvent("image-generated", {
				detail: { url: imageUrl, prompt },
			}));
		} catch (error) {
			const msg = error instanceof Error ? error.message : "Generation failed";
			this.#renderError(msg);
		} finally {
			this.#isGenerating = false;
			if (this.#generateBtn) this.#generateBtn.disabled = false;
		}
	}

	#preloadImage(url: string): Promise<void> {
		return new Promise((resolve) => {
			const img = new Image();
			img.onload = () => resolve();
			img.onerror = () => resolve();
			img.src = url;
		});
	}

	#renderLoading() {
		if (!this.#resultArea) return;
		this.#resultArea.innerHTML = `
			<div class="spinner-overlay">
				<div class="spinner"></div>
				<span class="spinner-text">Generating...</span>
			</div>
			${this.#lastResultUrl ? `<img src="${this.#escapeAttr(this.#lastResultUrl)}" alt="Previous result" style="opacity:0.3" />` : ""}
		`;
	}

	#renderResult(url: string, prompt: string) {
		if (!this.#resultArea) return;
		this.#resultArea.innerHTML = `<img src="${this.#escapeAttr(url)}" alt="${this.#escapeAttr(prompt)}" />`;
	}

	#renderError(msg: string) {
		if (!this.#resultArea) return;
		this.#resultArea.innerHTML = `
			<div class="result-placeholder">
				<span class="result-placeholder-icon">⚠️</span>
				<span style="color:#ef4444">${this.#escapeHtml(msg)}</span>
			</div>
		`;
	}

	#resizeCanvas(container: HTMLElement) {
		if (!this.#canvas) return;
		const rect = container.getBoundingClientRect();
		if (rect.width > 0 && rect.height > 0) {
			this.#canvas.width = rect.width * devicePixelRatio;
			this.#canvas.height = rect.height * devicePixelRatio;
			this.#canvas.style.width = rect.width + "px";
			this.#canvas.style.height = rect.height + "px";
			if (this.#ctx) {
				this.#ctx.scale(devicePixelRatio, devicePixelRatio);
			}
		}
	}

	#getCanvasPos(e: PointerEvent): { x: number; y: number } {
		const rect = this.#canvas!.getBoundingClientRect();
		return {
			x: e.clientX - rect.left,
			y: e.clientY - rect.top,
		};
	}

	#drawStroke(stroke: Stroke) {
		if (!this.#ctx || stroke.points.length < 2) return;
		const ctx = this.#ctx;

		ctx.lineCap = "round";
		ctx.lineJoin = "round";
		ctx.strokeStyle = stroke.color;

		const len = stroke.points.length;
		const p0 = stroke.points[len - 2];
		const p1 = stroke.points[len - 1];
		const pressure = (p0.pressure + p1.pressure) / 2;

		ctx.lineWidth = stroke.size * (0.5 + pressure);
		if (stroke.tool === "eraser") {
			ctx.globalCompositeOperation = "destination-out";
			ctx.lineWidth = stroke.size * 3;
		} else {
			ctx.globalCompositeOperation = "source-over";
		}

		ctx.beginPath();
		ctx.moveTo(p0.x, p0.y);
		ctx.lineTo(p1.x, p1.y);
		ctx.stroke();

		ctx.globalCompositeOperation = "source-over";
	}

	#redraw() {
		if (!this.#ctx || !this.#canvas) return;
		const ctx = this.#ctx;
		const w = this.#canvas.width / devicePixelRatio;
		const h = this.#canvas.height / devicePixelRatio;

		ctx.clearRect(0, 0, w, h);

		ctx.fillStyle = "#ffffff";
		ctx.fillRect(0, 0, w, h);

		for (const stroke of this.#strokes) {
			if (stroke.points.length < 2) continue;

			ctx.lineCap = "round";
			ctx.lineJoin = "round";
			ctx.strokeStyle = stroke.color;

			if (stroke.tool === "eraser") {
				ctx.globalCompositeOperation = "destination-out";
			} else {
				ctx.globalCompositeOperation = "source-over";
			}

			for (let i = 1; i < stroke.points.length; i++) {
				const p0 = stroke.points[i - 1];
				const p1 = stroke.points[i];
				const pressure = (p0.pressure + p1.pressure) / 2;
				ctx.lineWidth = stroke.size * (0.5 + pressure);

				ctx.beginPath();
				ctx.moveTo(p0.x, p0.y);
				ctx.lineTo(p1.x, p1.y);
				ctx.stroke();
			}
		}

		ctx.globalCompositeOperation = "source-over";
	}

	#makeCleanShape(gesture: string, original: Stroke): Stroke {
		const pts = original.points;
		const minX = Math.min(...pts.map(p => p.x));
		const maxX = Math.max(...pts.map(p => p.x));
		const minY = Math.min(...pts.map(p => p.y));
		const maxY = Math.max(...pts.map(p => p.y));
		const cx = (minX + maxX) / 2;
		const cy = (minY + maxY) / 2;
		const w = maxX - minX || 1;
		const h = maxY - minY || 1;
		const pressure = 0.5;

		const toStroke = (points: { x: number; y: number }[]): Stroke => ({
			points: points.map(p => ({ ...p, pressure })),
			color: original.color,
			size: original.size,
			tool: "pen",
		});

		switch (gesture) {
			case "circle": {
				const rx = w / 2, ry = h / 2;
				const circPts: { x: number; y: number }[] = [];
				for (let i = 0; i <= 48; i++) {
					const a = (i / 48) * Math.PI * 2;
					circPts.push({ x: cx + rx * Math.cos(a), y: cy + ry * Math.sin(a) });
				}
				return toStroke(circPts);
			}
			case "rectangle": {
				return toStroke([
					{ x: minX, y: minY }, { x: maxX, y: minY },
					{ x: maxX, y: maxY }, { x: minX, y: maxY },
					{ x: minX, y: minY },
				]);
			}
			case "triangle": {
				return toStroke([
					{ x: cx, y: minY }, { x: maxX, y: maxY },
					{ x: minX, y: maxY }, { x: cx, y: minY },
				]);
			}
			case "line": {
				// Use first and last point for direction
				const first = pts[0], last = pts[pts.length - 1];
				return toStroke([
					{ x: first.x, y: first.y },
					{ x: last.x, y: last.y },
				]);
			}
			case "arrow": {
				const first = pts[0], last = pts[pts.length - 1];
				const dx = last.x - first.x, dy = last.y - first.y;
				const len = Math.sqrt(dx * dx + dy * dy) || 1;
				const ux = dx / len, uy = dy / len;
				const headLen = Math.min(20, len * 0.3);
				// Arrow shaft + two head lines
				return toStroke([
					{ x: first.x, y: first.y }, { x: last.x, y: last.y },
					{ x: last.x - headLen * (ux + uy * 0.5), y: last.y - headLen * (uy - ux * 0.5) },
					{ x: last.x, y: last.y },
					{ x: last.x - headLen * (ux - uy * 0.5), y: last.y - headLen * (uy + ux * 0.5) },
				]);
			}
			case "check": {
				// V-shape: find the lowest point as the vertex
				const lowestIdx = pts.reduce((best, p, i) => p.y > pts[best].y ? i : best, 0);
				return toStroke([
					{ x: pts[0].x, y: pts[0].y },
					{ x: pts[lowestIdx].x, y: pts[lowestIdx].y },
					{ x: pts[pts.length - 1].x, y: pts[pts.length - 1].y },
				]);
			}
			default:
				return original;
		}
	}

	#showGestureBadge(name: string, score: number) {
		if (!this.#canvasArea) return;
		// Remove existing badge
		this.#canvasArea.querySelector(".gesture-badge")?.remove();
		const badge = document.createElement("div");
		badge.className = "gesture-badge";
		badge.textContent = `${name} (${Math.round(score * 100)}%)`;
		this.#canvasArea.appendChild(badge);
		setTimeout(() => badge.remove(), 1500);
	}

	#exportPNG() {
		if (!this.#canvas) return;
		const dataUrl = this.#canvas.toDataURL("image/png");
		const link = document.createElement("a");
		link.download = `drawfast-${Date.now()}.png`;
		link.href = dataUrl;
		link.click();
	}

	#escapeHtml(text: string): string {
		const div = document.createElement("div");
		div.textContent = text;
		return div.innerHTML;
	}

	#escapeAttr(text: string): string {
		return text.replace(/&/g, "&amp;").replace(/"/g, "&quot;").replace(/</g, "&lt;").replace(/>/g, "&gt;");
	}

	static override fromData(data: Record<string, any>): FolkDrawfast {
		const shape = FolkShape.fromData(data) as FolkDrawfast;
		return shape;
	}

	override toJSON() {
		return {
			...super.toJSON(),
			type: "folk-drawfast",
			strokes: this.#strokes.map((s) => ({
				points: s.points,
				color: s.color,
				size: s.size,
				tool: s.tool,
			})),
			prompt: this.#promptInput?.value || "",
			lastResultUrl: this.#lastResultUrl,
		};
	}

	override applyData(data: Record<string, any>): void {
		super.applyData(data);

		// Restore strokes from sync data
		if (data.strokes && Array.isArray(data.strokes)) {
			this.#strokes = data.strokes.map((s: any) => ({
				points: Array.isArray(s.points) ? s.points : [],
				color: s.color || "#0f172a",
				size: s.size || 4,
				tool: s.tool || "pen",
			}));
			this.#redraw();
		}

		// Restore prompt text
		if (data.prompt !== undefined && this.#promptInput) {
			this.#promptInput.value = data.prompt || "";
		}

		// Restore last generated image
		if (data.lastResultUrl && this.#resultArea) {
			this.#lastResultUrl = data.lastResultUrl;
			this.#renderResult(data.lastResultUrl, "");
		}
	}
}