import { Router, Response } from 'express';
import bcrypt from 'bcryptjs';
import jwt from 'jsonwebtoken';
import { users, refreshTokens, resetTokens } from '../db';
import { requireAuth } from '../middleware/requireAuth';
import { EmailService } from '../email/EmailService';
import { checkForgotPasswordRate, checkLoginRate, checkRegisterRate, sleep } from '../rateLimiter';
import { isSuperAdmin } from '../roles';

const router = Router();

const ACCESS_TOKEN_TTL  = '1h';
const COOKIE_DOMAIN     = process.env.COOKIE_DOMAIN  ?? '.rokojori.com';
const RESET_BASE_URL    = process.env.RESET_BASE_URL ?? 'https://account.rokojori.com';
const ACCOUNT_BASE_URL  = process.env.RESET_BASE_URL ?? 'https://account.rokojori.com';

function issueAccessToken( userId: string ): string
{
  const user = users.findById( userId )!;
  const payload =
  {
    userId:   user.id,
    email:    user.email,
    roles:    user.roles,
    products: user.products.map( p => p.id ),
    settings: user.settings
  };
  return jwt.sign( payload, process.env.JWT_SECRET ?? '', { expiresIn: ACCESS_TOKEN_TTL } );
}

function cookieOptions( maxAge: number )
{
  return {
    domain:   COOKIE_DOMAIN,
    httpOnly: true,
    secure:   process.env.NODE_ENV === 'production',
    sameSite: 'lax' as const,
    path:     '/'
  };
}

function setTokenCookie( res: Response, accessToken: string ): void
{
  res.cookie( 'accessToken', accessToken, { ...cookieOptions( 60 * 60 * 1000 ), maxAge: 60 * 60 * 1000 } );
}

function setRefreshTokenCookie( res: Response, token: string ): void
{
  res.cookie( 'refreshToken', token, { ...cookieOptions( 30 * 24 * 60 * 60 * 1000 ), maxAge: 30 * 24 * 60 * 60 * 1000 } );
}

function clearAuthCookies( res: Response ): void
{
  const base = { domain: COOKIE_DOMAIN, path: '/' };
  res.clearCookie( 'accessToken',  base );
  res.clearCookie( 'refreshToken', base );
}

function issueTokenPair( res: Response, userId: string ): { accessToken: string; refreshToken: string }
{
  const accessToken   = issueAccessToken( userId );
  const refreshRecord = refreshTokens.create( userId );
  setTokenCookie( res, accessToken );
  setRefreshTokenCookie( res, refreshRecord.token );
  return { accessToken, refreshToken: refreshRecord.token };
}

// POST /api/auth/register
router.post( '/register', async ( req, res ) =>
{
  const ip = req.ip ?? 'unknown';
  const { blocked } = checkRegisterRate( ip );
  if ( blocked ) { res.status( 429 ).json( { error: 'Too many registrations. Try again later.' } ); return; }

  const { email, password } = req.body as { email?: string; password?: string };
  if ( !email || !password )
  {
    res.status( 400 ).json( { error: 'Email and password required' } );
    return;
  }
  try
  {
    const passwordHash = await bcrypt.hash( password, 10 );
    const user = users.create( email, passwordHash );

    const superadminEmail = process.env.INITIAL_SUPERADMIN_EMAIL?.toLowerCase();
    if ( superadminEmail && email.toLowerCase() === superadminEmail )
    {
      const alreadyHasSuperAdmin = users.all().some( u => u.id !== user.id && isSuperAdmin( u.roles ) );
      if ( !alreadyHasSuperAdmin )
        users.update( user.id, { roles: [ 'superadmin', 'user' ] } );
    }

    const tokens = issueTokenPair( res, user.id );

    // Welcome email — non-blocking
    EmailService.sendEmail(
      email,
      'Welcome to rokojori',
      `Hi,\n\nYour account has been created at ${ACCOUNT_BASE_URL}.\n\nIf you did not create this account or want to delete it, visit:\n${ACCOUNT_BASE_URL}/profile.html\n\nYou can delete your account there at any time.`
    ).catch( () => {} );

    res.json( tokens );
  }
  catch
  {
    res.status( 409 ).json( { error: 'Email already registered' } );
  }
} );

// POST /api/auth/login
router.post( '/login', async ( req, res ) =>
{
  const ip = req.ip ?? 'unknown';
  const { blocked, delay } = checkLoginRate( ip );
  if ( blocked ) { res.status( 429 ).json( { error: 'Too many attempts. Try again later.' } ); return; }
  if ( delay ) await sleep( delay );

  const { email, password } = req.body as { email?: string; password?: string };
  const user = email ? users.findByEmail( email ) : undefined;
  if ( !user || !password || !( await bcrypt.compare( password, user.passwordHash ) ) )
  {
    res.status( 401 ).json( { error: 'Invalid credentials' } );
    return;
  }
  res.json( issueTokenPair( res, user.id ) );
} );

// POST /api/auth/logout
router.post( '/logout', ( req, res ) =>
{
  const tokenFromBody   = ( req.body as { refreshToken?: string } ).refreshToken;
  const tokenFromCookie = req.cookies?.refreshToken as string | undefined;
  const token = tokenFromBody ?? tokenFromCookie;
  if ( token ) refreshTokens.delete( token );
  clearAuthCookies( res );
  res.json( { ok: true } );
} );

// POST /api/auth/refresh  — non-browser clients (token in body)
router.post( '/refresh', ( req, res ) =>
{
  const { refreshToken } = req.body as { refreshToken?: string };
  if ( !refreshToken ) { res.status( 400 ).json( { error: 'Refresh token required' } ); return; }

  const record = refreshTokens.find( refreshToken );
  if ( !record || new Date( record.expiresAt ) < new Date() )
  {
    res.status( 401 ).json( { error: 'Invalid or expired refresh token' } );
    return;
  }
  const user = users.findById( record.userId );
  if ( !user ) { res.status( 401 ).json( { error: 'User not found' } ); return; }

  refreshTokens.delete( refreshToken );
  res.json( issueTokenPair( res, user.id ) );
} );

// GET /api/auth/refresh-session?redirect=...  — browser clients (token from cookie)
router.get( '/refresh-session', ( req, res ) =>
{
  const redirectTo   = req.query.redirect as string | undefined;
  const loginFallback = redirectTo
    ? `/login.html?redirect=${encodeURIComponent( redirectTo )}`
    : '/login.html';

  const token = req.cookies?.refreshToken as string | undefined;
  if ( !token ) { res.redirect( loginFallback ); return; }

  const record = refreshTokens.find( token );
  if ( !record || new Date( record.expiresAt ) < new Date() )
  {
    clearAuthCookies( res );
    res.redirect( loginFallback );
    return;
  }
  const user = users.findById( record.userId );
  if ( !user ) { clearAuthCookies( res ); res.redirect( loginFallback ); return; }

  refreshTokens.delete( token );
  issueTokenPair( res, user.id );
  res.redirect( redirectTo ?? '/profile.html' );
} );

// POST /api/auth/forgot-password  — rate-limited with escalating delay
router.post( '/forgot-password', async ( req, res ) =>
{
  const ip = req.ip ?? 'unknown';
  const { blocked, delay } = checkForgotPasswordRate( ip );
  if ( blocked ) { res.status( 429 ).json( { error: 'Too many attempts. Try again later.' } ); return; }
  await sleep( delay );

  const { email } = req.body as { email?: string };
  if ( !email ) { res.status( 400 ).json( { error: 'Email required' } ); return; }

  const user = users.findByEmail( email );
  if ( user )
  {
    const token = resetTokens.create( user.id );
    const link  = `${RESET_BASE_URL}/reset-password.html?token=${token.token}`;
    await EmailService.sendEmail(
      email,
      'Reset your password — rokojori',
      `Hi,\n\nClick the link below to reset your password. It expires in 1 hour.\n\n${link}\n\nIf you did not request this, you can safely ignore this email.`
    );
  }

  res.json( { ok: true } );
} );

// POST /api/auth/reset-password
router.post( '/reset-password', async ( req, res ) =>
{
  const { token, password } = req.body as { token?: string; password?: string };
  if ( !token || !password ) { res.status( 400 ).json( { error: 'Token and password required' } ); return; }

  const record = resetTokens.find( token );
  if ( !record || new Date( record.expiresAt ) < new Date() )
  {
    res.status( 400 ).json( { error: 'Invalid or expired token' } );
    return;
  }
  const passwordHash = await bcrypt.hash( password, 10 );
  users.update( record.userId, { passwordHash } );
  resetTokens.delete( token );
  res.json( { ok: true } );
} );

// GET /api/auth/reset-token-email
router.get( '/reset-token-email', ( req, res ) =>
{
  const token  = req.query.token as string | undefined;
  const record = token ? resetTokens.find( token ) : undefined;
  if ( !record || new Date( record.expiresAt ) < new Date() )
  {
    res.status( 400 ).json( { error: 'Invalid or expired token' } );
    return;
  }
  const user = users.findById( record.userId );
  if ( !user ) { res.status( 400 ).json( { error: 'User not found' } ); return; }
  res.json( { email: user.email } );
} );

// GET /api/auth/me
router.get( '/me', requireAuth, ( req, res ) =>
{
  const user = users.findById( req.auth!.userId );
  if ( !user ) { res.status( 404 ).json( { error: 'User not found' } ); return; }
  res.json(
  {
    id:       user.id,
    email:    user.email,
    roles:    user.roles,
    products: user.products,
    settings: user.settings
  } );
} );

// PATCH /api/auth/me/settings
router.patch( '/me/settings', requireAuth, ( req, res ) =>
{
  const user = users.findById( req.auth!.userId );
  if ( !user ) { res.status( 404 ).json( { error: 'User not found' } ); return; }
  const settings = { ...user.settings, ...( req.body as Record<string, unknown> ) };
  users.update( req.auth!.userId, { settings } );
  res.json( { settings } );
} );

// POST /api/auth/me/password
router.post( '/me/password', requireAuth, async ( req, res ) =>
{
  const { currentPassword, newPassword } = req.body as { currentPassword?: string; newPassword?: string };
  if ( !currentPassword || !newPassword )
  {
    res.status( 400 ).json( { error: 'Current and new password required' } );
    return;
  }
  const user = users.findById( req.auth!.userId );
  if ( !user ) { res.status( 404 ).json( { error: 'User not found' } ); return; }
  if ( !( await bcrypt.compare( currentPassword, user.passwordHash ) ) )
  {
    res.status( 401 ).json( { error: 'Current password is incorrect' } );
    return;
  }
  const passwordHash = await bcrypt.hash( newPassword, 10 );
  users.update( user.id, { passwordHash } );
  res.json( { ok: true } );
} );

// DELETE /api/auth/me
router.delete( '/me', requireAuth, ( req, res ) =>
{
  const userId = req.auth!.userId;
  refreshTokens.deleteForUser( userId );
  resetTokens.deleteForUser( userId );
  users.delete( userId );
  clearAuthCookies( res );
  res.json( { ok: true } );
} );

export default router;