import { Application, Router, type Context, type Next } from "jsr:@oak/oak";
import { join } from "jsr:@std/path";
import { Eta } from "jsr:@eta-dev/eta";

// Create Eta instance
const eta = new Eta({
  views: join(Deno.cwd(), "views"),
  cache: Deno.env.get("SERVICE_DOMAIN") === "production",
});

// Create Oak application
const app = new Application();
const router = new Router();

// Serve static files
app.use(async (ctx: Context, next: Next) => {
  const staticPath = join(Deno.cwd(), "static");
  
  try {
    // Strip /static prefix from path
    const path = ctx.request.url.pathname.replace(/^\/static/, '');
    
    await ctx.send({
      root: staticPath,
      path: path,
      index: "index.html",
    });
  } catch {
    await next();
  }
});

// Main route handler
router.get("/", async (ctx: Context) => {
  const params = ctx.request.url.searchParams;
  let back_to_url = params.get("back_to") || "";
  let domain = "";

  // If no back_to parameter, check host header
  if (!back_to_url) {
    const host = ctx.request.headers.get("host") || "";
    const serviceDomain = Deno.env.get("SERVICE_DOMAIN") || "localhost";
    const domainRegex = new RegExp(`^(${serviceDomain.replace(/\./g, '\\.')}|localhost)`);
    // Exclude our own hosts
    if (host && !domainRegex.test(host)) {
      back_to_url = `http://${host}`;
    }
  }

  // Extract domain from URL
  if (back_to_url) {
    try {
      domain = new URL(back_to_url).hostname;
    } catch {
      // Invalid URL, ignore
    }
  }

  // Render template with context
  const html = await eta.render("index", {
    back_to_url,
    domain: domain || "This part of the Internet",
  });

  ctx.response.body = html;
  ctx.response.type = "text/html";
});

app.use(router.routes());
app.use(router.allowedMethods());

// Start server
const port = 8080;
console.log(`Server running on http://localhost:${port}`);
await app.listen({ port });