import { env as globalEnv } from 'cloudflare:workers';
import type {
	CacheStorage as CLOUDFLARE_CACHESTORAGE,
	Request as CLOUDFLARE_REQUEST,
	ExecutionContext,
} from '@cloudflare/workers-types';
import type { SSRManifest } from 'astro';
import { App } from 'astro/app';
import { setGetEnv } from 'astro/env/setup';
import { createGetEnv } from '../utils/env.js';

setGetEnv(createGetEnv(globalEnv as Env));

type Env = {
	[key: string]: unknown;
	ASSETS: { fetch: (req: Request | string) => Promise<Response> };
	ASTRO_STUDIO_APP_TOKEN?: string;
};

export interface Runtime<T extends object = object> {
	runtime: {
		env: Env & T;
		cf: CLOUDFLARE_REQUEST['cf'];
		caches: CLOUDFLARE_CACHESTORAGE;
		ctx: ExecutionContext;
	};
}

declare global {
	// This is not a real global, but is injected using Vite define to allow us to specify the session binding name in the config.
	// eslint-disable-next-line no-var
	var __ASTRO_SESSION_BINDING_NAME: string;

	// Just used to pass the KV binding to unstorage.
	// eslint-disable-next-line no-var
	var __env__: Partial<Env>;
}

export function createExports(manifest: SSRManifest) {
	const app = new App(manifest);

	const fetch = async (
		request: Request & CLOUDFLARE_REQUEST,
		env: Env,
		context: ExecutionContext,
	) => {
		const { pathname } = new URL(request.url);
		const bindingName = globalThis.__ASTRO_SESSION_BINDING_NAME;
		// Assigning the KV binding to globalThis allows unstorage to access it for session storage.
		// unstorage checks in globalThis and globalThis.__env__ for the binding.
		globalThis.__env__ ??= {};
		globalThis.__env__[bindingName] = env[bindingName];

		// static assets fallback, in case default _routes.json is not used
		if (manifest.assets.has(pathname)) {
			return env.ASSETS.fetch(request.url.replace(/\.html$/, ''));
		}

		const routeData = app.match(request);
		if (!routeData) {
			// https://developers.cloudflare.com/pages/functions/api-reference/#envassetsfetch
			const asset = await env.ASSETS.fetch(
				request.url.replace(/index.html$/, '').replace(/\.html$/, ''),
			);
			if (asset.status !== 404) {
				return asset;
			}
		}

		Reflect.set(
			request,
			Symbol.for('astro.clientAddress'),
			request.headers.get('cf-connecting-ip'),
		);

		process.env.ASTRO_STUDIO_APP_TOKEN ??= (() => {
			if (typeof env.ASTRO_STUDIO_APP_TOKEN === 'string') {
				return env.ASTRO_STUDIO_APP_TOKEN;
			}
		})();

		const locals: Runtime = {
			runtime: {
				env: env,
				cf: request.cf,
				caches: caches as unknown as CLOUDFLARE_CACHESTORAGE,
				ctx: {
					waitUntil: (promise: Promise<any>) => context.waitUntil(promise),
					// Currently not available: https://developers.cloudflare.com/pages/platform/known-issues/#pages-functions
					passThroughOnException: () => {
						throw new Error(
							'`passThroughOnException` is currently not available in Cloudflare Pages. See https://developers.cloudflare.com/pages/platform/known-issues/#pages-functions.',
						);
					},
					props: {},
				},
			},
		};

		const response = await app.render(request, { routeData, locals });

		if (app.setCookieHeaders) {
			for (const setCookieHeader of app.setCookieHeaders(response)) {
				response.headers.append('Set-Cookie', setCookieHeader);
			}
		}

		return response;
	};

	return { default: { fetch } };
}