import { readFileSync } from "node:fs";
import { join } from "node:path";
import type { Hono } from "hono";
import { publicRepoNames } from "../server/db.ts";
import type { PageContext } from "./layout.ts";

// Kepr 2's mark, in Kepr's gold.
const FAVICON = readFileSync(join(import.meta.dir, "../../public/favicon.svg"));

// Chromium fetches a link's page while the pointer rests on it (2026-10-02), so a click opens at
// once. Never a link whose GET does something: a download, an archive or raw file, a counted feed
// or update check, Koh's routes, a backup, opening a notification (marks it read), or a form whose
// page sets a cookie or starts the issue form's spam timer.
const SPECULATION = JSON.stringify({
	prefetch: [
		{
			where: {
				and: [
					{ href_matches: "/*" },
					{
						not: {
							href_matches: [
								"/*/archive/*",
								"/*/raw/*",
								"/*/releases/*",
								"/*/install.sh",
								"/*/koh/*",
								"/*/update-info",
								"/*/meta",
								"/*/bundle*",
								"/*/file",
								"/source",
								"/api/*",
								"/admin/backup*",
								"/admin/notifications/*",
								"/admin/sign-out",
								"/*/issues/*",
								"/sign-in*",
								"/connect*",
							],
						},
					},
				],
			},
			eagerness: "moderate",
		},
	],
});

/** §22.6: robots.txt, the sitemap (public repos only, as everywhere, §20) and the favicon. */
export function registerHousekeeping(app: Hono, ctx: PageContext): void {
	const origin = `https://${ctx.domain}`;
	app.get("/speculation.json", (c) =>
		c.body(SPECULATION, 200, {
			"Content-Type": "application/speculationrules+json",
			"Cache-Control": "public, max-age=3600",
		}),
	);
	app.get("/robots.txt", (c) =>
		c.body(`User-agent: *\nAllow: /\n\nSitemap: ${origin}/sitemap.xml\n`, 200, {
			"Content-Type": "text/plain; charset=UTF-8",
		}),
	);
	app.get("/sitemap.xml", (c) => {
		const url = (path: string, changefreq: string, priority: string) =>
			`  <url><loc>${
				origin
			}${path}</loc><changefreq>${changefreq}</changefreq><priority>${priority}</priority></url>\n`;
		const urls = [
			url("/", "daily", "1.0"),
			url("/browse", "daily", "0.9"),
			url("/docs", "weekly", "0.8"),
			// Repo names are [A-Za-z0-9._-] (§9.2's check at sync), so they need no XML escaping.
			...publicRepoNames(ctx.kepr).map((name) => url(`/${name}`, "daily", "0.7")),
		];
		return c.body(
			`<?xml version="1.0" encoding="UTF-8"?>\n<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">\n${urls.join(
				"",
			)}</urlset>\n`,
			200,
			{ "Content-Type": "application/xml; charset=UTF-8", "Cache-Control": "public, max-age=3600" },
		);
	});
	app.get("/favicon.svg", (c) =>
		c.body(FAVICON, 200, {
			"Content-Type": "image/svg+xml",
			"Cache-Control": "public, max-age=86400",
		}),
	);
}