import AnimationTitles from '../../src/data/animation-titles.json';
import ActorDisplayNames from '../../src/data/actor-display-names.json';
import { fromUrlSafeBase64 } from '../../src/core/base64.js';

interface Env {
	ASSETS: R2Bucket;
	API_URL: string;
}

function escapeHtml(str: string): string {
	return str
		.replace(/&/g, '&')
		.replace(/</g, '&lt;')
		.replace(/>/g, '&gt;')
		.replace(/"/g, '&quot;');
}

function formatDateTime(timestamp: number): string {
	if (!timestamp) return '';
	const d = new Date(timestamp * 1000);
	const date = d.toLocaleDateString('en-US', { month: 'short', day: 'numeric', year: 'numeric' });
	const time = d.toLocaleTimeString('en-US', { hour: 'numeric', minute: '2-digit' });
	return `${date} \u00b7 ${time}`;
}

interface Participant {
	n?: string;
	displayName?: string;
	c?: number;
	charIndex?: number;
}

function buildDescription(participants: Participant[], timestamp?: number): string {
	const parts: string[] = [];
	for (const p of participants) {
		const name = p.displayName || p.n || 'Unknown';
		const charIndex = p.charIndex ?? p.c ?? 0;
		const charName = (ActorDisplayNames as string[])[charIndex] || `#${charIndex}`;
		parts.push(`${name} as ${charName}`);
	}
	if (timestamp) {
		parts.push(formatDateTime(timestamp));
	}
	return parts.join(' \u00b7 ');
}

function injectOgTags(html: string, title: string, description: string, url: string): string {
	const safeTitle = escapeHtml(title);
	const safeDesc = escapeHtml(description);
	const safeUrl = escapeHtml(url);
	const fullTitle = `${safeTitle} — LEGO® Island`;

	html = html.replace(/<title>[^<]*<\/title>/, `<title>${fullTitle}</title>`);

	html = html.replace(
		/(<meta\s+property="og:title"\s+content=")[^"]*(")/,
		`$1${safeTitle}$2`
	);
	html = html.replace(
		/(<meta\s+property="og:description"\s+content=")[^"]*(")/,
		`$1${safeDesc}$2`
	);
	html = html.replace(
		/(<meta\s+property="og:url"\s+content=")[^"]*(")/,
		`$1${safeUrl}$2`
	);

	html = html.replace(
		/(<meta\s+name="twitter:title"\s+content=")[^"]*(")/,
		`$1${safeTitle}$2`
	);
	html = html.replace(
		/(<meta\s+name="twitter:description"\s+content=")[^"]*(")/,
		`$1${safeDesc}$2`
	);
	html = html.replace(
		/(<meta\s+name="twitter:url"\s+content=")[^"]*(")/,
		`$1${safeUrl}$2`
	);

	html = html.replace(
		/(<meta\s+name="description"\s+content=")[^"]*(")/,
		`$1${safeDesc}$2`
	);

	html = html.replace(
		/(<link\s+rel="canonical"\s+href=")[^"]*(")/,
		`$1${safeUrl}$2`
	);

	return html;
}

function getR2Prefix(request: Request): string {
	const hostname = new URL(request.url).hostname;
	return hostname.startsWith('dev.') ? 'dev/' : '';
}

async function getIndexHtml(request: Request, env: Env): Promise<string> {
	const key = `${getR2Prefix(request)}index.html`;
	const obj = await env.ASSETS.get(key);
	if (!obj) throw new Error(`${key} not found in R2`);
	return obj.text();
}

async function handleMemory(eventId: string, request: Request, env: Env): Promise<Response> {
	const html = await getIndexHtml(request, env);

	try {
		const apiRes = await fetch(`${env.API_URL}/api/memory/${encodeURIComponent(eventId)}`);
		if (!apiRes.ok) {
			return new Response(html, { headers: { 'content-type': 'text/html; charset=utf-8' } });
		}

		const data = await apiRes.json() as {
			animIndex: number;
			participants: Participant[];
			completedAt?: number;
		};

		const titles = AnimationTitles as Record<string, string>;
		const title = titles[String(data.animIndex)] || `Animation #${data.animIndex}`;
		const description = buildDescription(data.participants, data.completedAt);
		const url = new URL(request.url);

		return new Response(injectOgTags(html, title, description, url.href), {
			headers: {
				'content-type': 'text/html; charset=utf-8',
				'cache-control': 'public, max-age=300',
			},
		});
	} catch {
		return new Response(html, { headers: { 'content-type': 'text/html; charset=utf-8' } });
	}
}

async function handleScene(encoded: string, request: Request, env: Env): Promise<Response> {
	const html = await getIndexHtml(request, env);

	try {
		const json = fromUrlSafeBase64(encoded);
		const data = JSON.parse(json) as {
			a: number;
			p: Array<{ n: string; c: number }>;
			t?: number;
		};

		const titles = AnimationTitles as Record<string, string>;
		const title = titles[String(data.a)] || `Animation #${data.a}`;
		const participants = data.p.map(p => ({ n: p.n, c: p.c }));
		const description = buildDescription(participants, data.t);
		const url = new URL(request.url);

		return new Response(injectOgTags(html, title, description, url.href), {
			headers: {
				'content-type': 'text/html; charset=utf-8',
				'cache-control': 'public, max-age=3600',
			},
		});
	} catch {
		return new Response(html, { headers: { 'content-type': 'text/html; charset=utf-8' } });
	}
}

export default {
	async fetch(request: Request, env: Env): Promise<Response> {
		const url = new URL(request.url);
		const path = url.pathname;

		const memoryMatch = path.match(/^\/memory\/([A-Za-z0-9_-]+)$/);
		if (memoryMatch) {
			return handleMemory(memoryMatch[1], request, env);
		}

		const sceneMatch = path.match(/^\/scene\/([A-Za-z0-9_-]+)$/);
		if (sceneMatch) {
			return handleScene(sceneMatch[1], request, env);
		}

		return new Response('Not found', { status: 404 });
	},
};