import { packageContext } from 'kody:runtime'
import { ASSETS } from './assets.ts'
import { renderPage, type PageCtx } from './page.ts'

const HOST = /^[a-z0-9.-]+(:\d{1,5})?$/i
const FALLBACK_ORIGIN = 'https://kentcdodds.kody.run'

/** Public origin for absolute og:image URLs. The runtime may rewrite request.url, so prefer the forwarded/Host header. */
function publicOrigin(request: Request, url: URL) {
	const raw = (request.headers.get('x-forwarded-host') || request.headers.get('host') || url.host).split(',')[0]!.trim()
	if (!HOST.test(raw)) return FALLBACK_ORIGIN
	const local = /^(localhost|127\.|\[::1\])/.test(raw)
	return `${local ? 'http' : 'https'}://${raw.toLowerCase()}`
}

function asset(path: string) {
	const a = ASSETS[path]
	if (!a) return null
	const bytes = Uint8Array.from(atob(a.b64), (c) => c.charCodeAt(0))
	return new Response(bytes, { headers: { 'content-type': a.type, 'cache-control': 'public, max-age=3600' } })
}

export default {
	async fetch(request: Request) {
		const url = new URL(request.url)
		const appBase = String(packageContext?.appBasePath ?? '').replace(/\/+$/, '')
		let path = url.pathname
		if (appBase && path.startsWith(appBase)) path = path.slice(appBase.length)
		path = path.replace(/\/+$/, '') || '/'
		if (path.endsWith('/health')) {
			return Response.json({ ok: true, service: 'roadster' })
		}
		const img = asset(path)
		if (img) return img
		const clientModuleUrl = packageContext?.clientModuleUrl ?? null
		if (!clientModuleUrl) {
			return new Response('Game client is not available yet. Try again after publish.', {
				status: 503,
				headers: { 'content-type': 'text/plain; charset=utf-8' },
			})
		}
		const ctx: PageCtx = { origin: publicOrigin(request, url), appBase }
		return new Response(renderPage(clientModuleUrl, ctx), {
			headers: {
				'content-type': 'text/html; charset=utf-8',
				'cache-control': 'no-cache',
			},
		})
	},
}