import { COOKIE_NAME, ONE_YEAR_MS } from "@shared/const";
import type { Express, Request, Response } from "express";
import * as db from "../db";
import { getSessionCookieOptions } from "./cookies";
import { sdk } from "./sdk";
import { ENV } from "./env";

function getQueryParam(req: Request, key: string): string | undefined {
  const value = req.query[key];
  return typeof value === "string" ? value : undefined;
}

// Dev user for development mode
const DEV_USER = {
  openId: "dev-user-001",
  name: "Dev User",
  email: "dev@localhost",
  loginMethod: "dev",
};

// Check if HuggingFace OAuth is configured
function isHfOAuthConfigured(): boolean {
  return !!(ENV.hfOAuthClientId && ENV.hfOAuthClientSecret);
}

// Get the base URL for redirects
function getBaseUrl(req: Request): string {
  if (ENV.hfSpaceHost) {
    return `https://${ENV.hfSpaceHost}`;
  }
  const protocol = req.headers["x-forwarded-proto"] || req.protocol;
  const host = req.headers["x-forwarded-host"] || req.headers.host;
  return `${protocol}://${host}`;
}

export function registerOAuthRoutes(app: Express) {
  // HuggingFace OAuth login route
  app.get("/api/hf/login", (req: Request, res: Response) => {
    if (!isHfOAuthConfigured()) {
      res.status(400).json({ error: "HuggingFace OAuth not configured" });
      return;
    }

    const baseUrl = getBaseUrl(req);
    const redirectUri = `${baseUrl}/api/hf/callback`;
    const scope = "openid profile";
    const state = Buffer.from(JSON.stringify({ redirect: "/" })).toString("base64");

    const authUrl = new URL("https://huggingface.co/oauth/authorize");
    authUrl.searchParams.set("client_id", ENV.hfOAuthClientId);
    authUrl.searchParams.set("redirect_uri", redirectUri);
    authUrl.searchParams.set("response_type", "code");
    authUrl.searchParams.set("scope", scope);
    authUrl.searchParams.set("state", state);

    console.log("[HF OAuth] Redirecting to:", authUrl.toString());
    res.redirect(302, authUrl.toString());
  });

  // HuggingFace OAuth callback
  app.get("/api/hf/callback", async (req: Request, res: Response) => {
    const code = getQueryParam(req, "code");
    const error = getQueryParam(req, "error");

    if (error) {
      console.error("[HF OAuth] Error:", error);
      res.status(400).json({ error: `OAuth error: ${error}` });
      return;
    }

    if (!code) {
      res.status(400).json({ error: "Missing authorization code" });
      return;
    }

    try {
      const baseUrl = getBaseUrl(req);
      const redirectUri = `${baseUrl}/api/hf/callback`;

      // Exchange code for token
      const tokenResponse = await fetch("https://huggingface.co/oauth/token", {
        method: "POST",
        headers: { "Content-Type": "application/x-www-form-urlencoded" },
        body: new URLSearchParams({
          grant_type: "authorization_code",
          client_id: ENV.hfOAuthClientId,
          client_secret: ENV.hfOAuthClientSecret,
          code,
          redirect_uri: redirectUri,
        }),
      });

      if (!tokenResponse.ok) {
        const errorText = await tokenResponse.text();
        console.error("[HF OAuth] Token exchange failed:", errorText);
        res.status(400).json({ error: "Token exchange failed" });
        return;
      }

      const tokens = await tokenResponse.json() as { access_token: string };

      // Get user info
      const userInfoResponse = await fetch("https://huggingface.co/oauth/userinfo", {
        headers: { Authorization: `Bearer ${tokens.access_token}` },
      });

      if (!userInfoResponse.ok) {
        res.status(400).json({ error: "Failed to get user info" });
        return;
      }

      const userInfo = await userInfoResponse.json() as {
        sub: string;
        name?: string;
        preferred_username?: string;
        email?: string;
      };

      const openId = `hf-${userInfo.sub}`;
      const name = userInfo.name || userInfo.preferred_username || "HF User";
      const email = userInfo.email || null;

      // Save user to database
      try {
        await db.upsertUser({
          openId,
          name,
          email,
          loginMethod: "huggingface",
          lastSignedIn: new Date(),
        });
      } catch (dbError) {
        console.log("[HF OAuth] Database not available, proceeding without persistence");
      }

      // Create session
      const sessionToken = await sdk.createSessionToken(openId, {
        name,
        expiresInMs: ONE_YEAR_MS,
      });

      const cookieOptions = getSessionCookieOptions(req);
      res.cookie(COOKIE_NAME, sessionToken, { ...cookieOptions, maxAge: ONE_YEAR_MS });

      console.log("[HF OAuth] User logged in:", name);
      
      // Use client-side redirect instead of 302 - Safari has issues with cookies on redirects
      res.setHeader("Content-Type", "text/html");
      res.send(`<!DOCTYPE html>
<html><head>
<meta http-equiv="refresh" content="0;url=/">
<script>window.location.href="/";</script>
</head><body>Redirecting...</body></html>`);
    } catch (error) {
      console.error("[HF OAuth] Callback error:", error);
      res.status(500).json({ error: "OAuth callback failed" });
    }
  });

  // Development/Demo login route - enabled when HF OAuth is not configured
  app.get("/api/dev/login", async (req: Request, res: Response) => {
    // Allow demo login if HF OAuth is not configured (demo mode)
    const isDev = process.env.NODE_ENV !== "production";
    const isDemo = !isHfOAuthConfigured(); // Allow demo login when no HF OAuth
    
    if (!isDev && !isDemo) {
      res.status(403).json({ error: "Login not available - please configure HuggingFace OAuth" });
      return;
    }

    try {
      // Try to create or update dev user in database (optional)
      try {
        await db.upsertUser({
          openId: DEV_USER.openId,
          name: DEV_USER.name,
          email: DEV_USER.email,
          loginMethod: DEV_USER.loginMethod,
          lastSignedIn: new Date(),
        });
      } catch (dbError) {
        // Database not available - that's OK for dev mode
        console.log("[DevAuth] Database not available, proceeding without user persistence");
      }

      // Create session token
      const sessionToken = await sdk.createSessionToken(DEV_USER.openId, {
        name: DEV_USER.name,
        expiresInMs: ONE_YEAR_MS,
      });

      // Set session cookie
      const cookieOptions = getSessionCookieOptions(req);
      res.cookie(COOKIE_NAME, sessionToken, { ...cookieOptions, maxAge: ONE_YEAR_MS });

      console.log("[DevAuth] Dev user logged in:", DEV_USER.email);
      
      // Use client-side redirect instead of 302 - Safari has issues with cookies on redirects
      res.setHeader("Content-Type", "text/html");
      res.send(`<!DOCTYPE html>
<html><head>
<meta http-equiv="refresh" content="0;url=/">
<script>window.location.href="/";</script>
</head><body>Redirecting...</body></html>`);
    } catch (error) {
      console.error("[DevAuth] Dev login failed:", error);
      res.status(500).json({ error: "Dev login failed" });
    }
  });

  // Endpoint to check auth config (used by frontend)
  app.get("/api/auth/config", (req: Request, res: Response) => {
    const hfOAuthEnabled = isHfOAuthConfigured();
    res.json({
      hfOAuthEnabled,
      // Dev/demo login is enabled in dev mode OR when HF OAuth is not configured
      devLoginEnabled: process.env.NODE_ENV !== "production" || !hfOAuthEnabled,
    });
  });

  app.get("/api/oauth/callback", async (req: Request, res: Response) => {
    const code = getQueryParam(req, "code");
    const state = getQueryParam(req, "state");

    if (!code || !state) {
      res.status(400).json({ error: "code and state are required" });
      return;
    }

    try {
      const tokenResponse = await sdk.exchangeCodeForToken(code, state);
      const userInfo = await sdk.getUserInfo(tokenResponse.accessToken);

      if (!userInfo.openId) {
        res.status(400).json({ error: "openId missing from user info" });
        return;
      }

      await db.upsertUser({
        openId: userInfo.openId,
        name: userInfo.name || null,
        email: userInfo.email ?? null,
        loginMethod: userInfo.loginMethod ?? userInfo.platform ?? null,
        lastSignedIn: new Date(),
      });

      const sessionToken = await sdk.createSessionToken(userInfo.openId, {
        name: userInfo.name || "",
        expiresInMs: ONE_YEAR_MS,
      });

      const cookieOptions = getSessionCookieOptions(req);
      res.cookie(COOKIE_NAME, sessionToken, { ...cookieOptions, maxAge: ONE_YEAR_MS });

      res.redirect(302, "/");
    } catch (error) {
      console.error("[OAuth] Callback failed", error);
      res.status(500).json({ error: "OAuth callback failed" });
    }
  });
}