/**
 * Page & static file routes.
 *
 * Handles: dashboard SPA, docs, embed.js, pairing pages, root redirect.
 * Returns true if the request was handled, false to continue to API routes.
 */

import { IncomingMessage, ServerResponse } from "http";
import { existsSync, readFileSync } from "fs";
import { join, extname } from "path";
import { resolveSessionToWorkspace } from "../auth.js";
import type * as fileStore from "../store.js";

// Template rendering
const EXTENSION_URL = "https://chromewebstore.google.com/detail/hanzi-browse/iklpkemlmbhemkiojndpbhoakgikpmcd";
const templateDir = join(new URL(import.meta.url).pathname, "../../templates");

function renderTemplate(filename: string, vars: Record<string, string>): string {
  let html = readFileSync(join(templateDir, filename), "utf-8");
  for (const [key, value] of Object.entries(vars)) {
    html = html.replaceAll(`{{${key}}}`, value);
  }
  return html;
}

function getSelfPairPageHtml(token: string, host: string): string {
  const apiUrl = host.includes("localhost") ? `http://${host}` : `https://${host}`;
  const safeToken = token.replace(/[<>"'&]/g, "");
  return renderTemplate("pair-self.html", { TOKEN: safeToken, API_URL: apiUrl });
}

function getPairingPageHtml(token: string, host: string): string {
  const apiUrl = host.includes("localhost") ? `http://${host}` : `https://${host}`;
  const safeToken = token.replace(/[<>"'&]/g, "");
  return renderTemplate("pair.html", { TOKEN: safeToken, API_URL: apiUrl, EXTENSION_URL });
}

const MIME_TYPES: Record<string, string> = {
  ".html": "text/html", ".js": "application/javascript",
  ".css": "text/css", ".json": "application/json",
  ".svg": "image/svg+xml", ".png": "image/png",
};

/**
 * Try to handle the request as a page/static file route.
 * Returns true if handled (response sent), false otherwise.
 */
export async function handlePageRoutes(
  req: IncomingMessage,
  res: ServerResponse,
  S: typeof fileStore,
): Promise<boolean> {
  const { method, url } = req;
  if (method !== "GET") return false;

  // --- Dashboard SPA ---
  if (url?.startsWith("/dashboard")) {
    const thisFile = new URL(import.meta.url).pathname;
    const dashboardDir = join(thisFile, "../../../dashboard");
    const filePath = url === "/dashboard" || url === "/dashboard/"
      ? join(dashboardDir, "index.html")
      : join(dashboardDir, url.replace("/dashboard/", ""));

    if (existsSync(filePath)) {
      const ext = extname(filePath);
      const cacheControl = ext === ".html" ? "no-cache, no-store, must-revalidate" : "public, max-age=31536000, immutable";
      res.writeHead(200, { "Content-Type": MIME_TYPES[ext] || "application/octet-stream", "Cache-Control": cacheControl });
      res.end(readFileSync(filePath));
      return true;
    }
    // SPA fallback
    const indexPath = join(dashboardDir, "index.html");
    if (existsSync(indexPath)) {
      res.writeHead(200, { "Content-Type": "text/html", "Cache-Control": "no-cache, no-store, must-revalidate" });
      res.end(readFileSync(indexPath));
      return true;
    }
  }

  // --- Root redirect ---
  if (url === "/") {
    const session = await resolveSessionToWorkspace(req);
    if (session) {
      res.writeHead(302, { Location: "/dashboard" });
    } else {
      res.writeHead(302, { Location: "https://browse.hanzilla.co" });
    }
    res.end();
    return true;
  }

  // --- Docs ---
  if (url === "/docs.html" || url?.startsWith("/docs.html")) {
    const filePath = join(process.cwd(), "landing", "docs.html");
    if (existsSync(filePath)) {
      res.writeHead(200, { "Content-Type": "text/html" });
      res.end(readFileSync(filePath));
      return true;
    }
  }

  // --- Embeddable pairing component ---
  if (url === "/embed.js") {
    const embedPath = join(process.cwd(), "landing/embed.js");
    if (existsSync(embedPath)) {
      res.writeHead(200, {
        "Content-Type": "application/javascript",
        "Access-Control-Allow-Origin": "*",
        "Cache-Control": "public, max-age=3600",
      });
      res.end(readFileSync(embedPath));
    } else {
      res.writeHead(404);
      res.end("Not found");
    }
    return true;
  }

  // --- Legacy pairing snippet ---
  if (url === "/hanzi-pair.js") {
    const snippetPath = join(process.cwd(), "sdk/hanzi-pair.js");
    if (existsSync(snippetPath)) {
      res.writeHead(200, {
        "Content-Type": "application/javascript",
        "Access-Control-Allow-Origin": "*",
        "Cache-Control": "public, max-age=3600",
      });
      res.end(readFileSync(snippetPath));
    } else {
      res.writeHead(404);
      res.end("Not found");
    }
    return true;
  }

  // --- Self-service pairing (/pair-self) ---
  if (url === "/pair-self") {
    const session = await resolveSessionToWorkspace(req);
    if (!session) {
      res.writeHead(302, { Location: "/api/auth/sign-in/social?provider=google&callbackURL=/pair-self" });
      res.end();
      return true;
    }
    try {
      const wsKeys = await S.listApiKeys(session.workspaceId);
      const createdBy = wsKeys.length > 0 ? wsKeys[0].id : session.workspaceId;
      const token = await S.createPairingToken(session.workspaceId, createdBy, { label: "Sidepanel", source: "self" });
      res.writeHead(200, { "Content-Type": "text/html; charset=utf-8" });
      res.end(getSelfPairPageHtml(token._plainToken, req.headers.host || ""));
    } catch (err: any) {
      res.writeHead(500, { "Content-Type": "text/html" });
      res.end(`<html><body><p>Error: ${err.message}</p><a href="/pair-self">Try again</a></body></html>`);
    }
    return true;
  }

  // --- Hosted pairing page (/pair/:token) ---
  const pairMatch = url?.match(/^\/pair\/(.+)$/);
  if (pairMatch) {
    res.writeHead(200, { "Content-Type": "text/html; charset=utf-8" });
    res.end(getPairingPageHtml(pairMatch[1], req.headers.host || ""));
    return true;
  }

  return false;
}