import { env } from "cloudflare:workers";
import { contentType, decodePath, lookup, SECURITY_HEADERS } from "../pages/serve";
import { objectKey } from "../pages/config";
import { manifestKey } from "./config";
import type { SiteManifest } from "./config";

const MANIFEST_CACHE_SECONDS = 3600;
const HTTP_OK = 200;

export function plain(status: number, body: string, extra: Record<string, string> = {}): Response {
  return new Response(body, {
    status,
    headers: {
      ...SECURITY_HEADERS,
      "content-type": "text/plain; charset=utf-8",
      "cache-control": "no-store",
      ...extra,
    },
  });
}

export function html(status: number, body: string, extra: Record<string, string> = {}): Response {
  return new Response(body, {
    status,
    headers: {
      ...SECURITY_HEADERS,
      "content-type": "text/html; charset=utf-8",
      "cache-control": "no-store",
      "content-security-policy":
        "default-src 'none'; style-src 'unsafe-inline'; form-action 'self'; frame-ancestors 'none'",
      ...extra,
    },
  });
}

export function loadManifest(deploymentId: string): Promise<SiteManifest | null> {
  return env.KV.get<SiteManifest>(manifestKey(deploymentId), { type: "json", cacheTtl: MANIFEST_CACHE_SECONDS });
}

/** Serves a static asset from a deployment's manifest; identical semantics to Pages. */
export async function serveStatic(
  request: Request,
  manifest: SiteManifest,
  spa: boolean,
  gated = false,
): Promise<Response> {
  if (request.method !== "GET" && request.method !== "HEAD") return plain(405, "Method not allowed");
  const path = decodePath(new URL(request.url).pathname);
  if (path === null) return plain(400, "Bad path");
  const found = lookup({ files: manifest.files }, spa, path, "/");
  if (!found) return plain(404, "Not found");
  if ("redirect" in found)
    return new Response(null, { status: 308, headers: { ...SECURITY_HEADERS, location: found.redirect } });
  const [sha, size] = found.file;
  const etag = `"${sha}"`;
  const headers: Record<string, string> = {
    ...SECURITY_HEADERS,
    "content-type": contentType(found.path),
    etag,
    "cache-control": `${gated ? "private" : "public"}, ${found.path.endsWith(".html") ? "max-age=0, must-revalidate" : "max-age=600"}`,
  };
  if (gated) headers.vary = "cookie";
  if (found.status === HTTP_OK && request.headers.get("if-none-match") === etag) {
    return new Response(null, { status: 304, headers });
  }
  if (request.method === "HEAD") {
    return new Response(null, { status: found.status, headers: { ...headers, "content-length": String(size) } });
  }
  const object = await env.BUCKET.get(objectKey(sha));
  if (!object) return plain(503, "Deployment object missing");
  return new Response(object.body, {
    status: found.status,
    headers: { ...headers, "content-length": String(object.size) },
  });
}