/**
 * The process the forge runs. `serve` opens the database and listens:
 * every request gets the floor (`http.ts`), an identity (`who.ts`), the
 * door (`security.ts`) and one route (`routes.ts`) — so a request from
 * another site, from someone going too fast, or from someone the contract
 * turns away is refused before a byte of it is read. Run directly, it
 * serves what the forge said; a test calls `serve` with its own.
 */

import { openDb } from "./db.ts";
import { dataDir, identityKey, title, where } from "./env.ts";
import { html, text } from "./http.ts";
import { match } from "./routes.ts";
import { door } from "./security.ts";
import { who } from "./who.ts";

export interface ServeOptions {
  readonly port: number;
  readonly hostname?: string | undefined;
  readonly dataDir: string;
  readonly identityKey: string;
}

export function serve(options: ServeOptions) {
  const db = openDb(options.dataDir);
  return Bun.serve({
    port: options.port,
    hostname: options.hostname ?? "127.0.0.1",
    // A connection that says nothing for a minute is dropped. The event
    // stream heartbeats every 25 seconds to stay well inside that.
    idleTimeout: 60,
    async fetch(request, server) {
      const url = new URL(request.url);
      const me = who(request, options.identityKey);
      const refused = door(
        db,
        request,
        url,
        me,
        server.requestIP(request)?.address ?? "?",
      );
      if (refused !== undefined) return head(request, refused);
      const found = match(
        request.method === "HEAD" ? "GET" : request.method,
        url.pathname,
      );
      if (found === undefined) return text("not found", 404);
      const response = await found.route.handle({
        request,
        url,
        db,
        who: me,
        params: found.params,
      });
      return head(request, response);
    },
    // A bug answers with the floor and nothing else: never the runtime's
    // own error page, which carries source and paths, and never without
    // the headers. The detail goes to the log, where it belongs.
    error(error) {
      console.error(error);
      return html("<h1>Something went wrong</h1>", 500);
    },
  });
}

// HEAD is GET without the body: a health check sees the app up.
const head = (request: Request, response: Response): Response =>
  request.method === "HEAD"
    ? new Response(null, { status: response.status, headers: response.headers })
    : response;

if (import.meta.main) {
  const server = serve({
    port: Number(process.env.PORT ?? 8080),
    hostname: process.env.HOST,
    dataDir,
    identityKey,
  });
  console.log(
    `${title} listening on http://${server.hostname}:${server.port} (${where})`,
  );
}