import { NextRequest, NextResponse } from 'next/server';
import { cookies } from 'next/headers';

const KEYCLOAK_URL = process.env.NEXT_PUBLIC_KEYCLOAK_URL || 'https://security.lions.dev';
const KEYCLOAK_REALM = process.env.NEXT_PUBLIC_KEYCLOAK_REALM || 'btpxpress';
const CLIENT_ID = process.env.NEXT_PUBLIC_KEYCLOAK_CLIENT_ID || 'btpxpress-frontend';
const REDIRECT_URI = process.env.NEXT_PUBLIC_APP_URL
  ? `${process.env.NEXT_PUBLIC_APP_URL}/auth/callback`
  : 'https://btpxpress.lions.dev/auth/callback';

const TOKEN_ENDPOINT = `${KEYCLOAK_URL}/realms/${KEYCLOAK_REALM}/protocol/openid-connect/token`;

export async function POST(request: NextRequest) {
  console.log('🔐 Token exchange API called');

  try {
    const body = await request.json();
    const { code, state } = body;

    if (!code) {
      console.error('❌ No authorization code provided');
      return NextResponse.json(
        { error: 'Code d\'autorisation manquant' },
        { status: 400 }
      );
    }

    console.log('✅ Exchanging code with Keycloak...');
    console.log('📍 Token endpoint:', TOKEN_ENDPOINT);
    console.log('📍 Client ID:', CLIENT_ID);
    console.log('📍 Redirect URI:', REDIRECT_URI);

    // Préparer les paramètres pour l'échange de code
    const params = new URLSearchParams({
      grant_type: 'authorization_code',
      client_id: CLIENT_ID,
      code: code,
      redirect_uri: REDIRECT_URI,
    });

    // Échanger le code contre des tokens
    const tokenResponse = await fetch(TOKEN_ENDPOINT, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/x-www-form-urlencoded',
      },
      body: params.toString(),
    });

    if (!tokenResponse.ok) {
      const errorText = await tokenResponse.text();
      console.error('❌ Keycloak token exchange failed:', tokenResponse.status, errorText);

      let errorData;
      try {
        errorData = JSON.parse(errorText);
      } catch {
        errorData = { error: 'Token exchange failed', details: errorText };
      }

      return NextResponse.json(
        {
          error: errorData.error || 'Échec de l\'échange de token',
          error_description: errorData.error_description || 'Erreur lors de la communication avec Keycloak',
          details: errorData
        },
        { status: tokenResponse.status }
      );
    }

    const tokens = await tokenResponse.json();
    console.log('✅ Tokens received from Keycloak');

    // Stocker les tokens dans des cookies HttpOnly sécurisés
    const cookieStore = cookies();
    const isProduction = process.env.NODE_ENV === 'production';

    // Access token (durée: expires_in secondes)
    cookieStore.set('access_token', tokens.access_token, {
      httpOnly: true,
      secure: isProduction,
      sameSite: 'lax',
      maxAge: tokens.expires_in || 300, // Par défaut 5 minutes
      path: '/',
    });

    // Refresh token (durée plus longue)
    if (tokens.refresh_token) {
      cookieStore.set('refresh_token', tokens.refresh_token, {
        httpOnly: true,
        secure: isProduction,
        sameSite: 'lax',
        maxAge: tokens.refresh_expires_in || 1800, // Par défaut 30 minutes
        path: '/',
      });
    }

    // ID token
    if (tokens.id_token) {
      cookieStore.set('id_token', tokens.id_token, {
        httpOnly: true,
        secure: isProduction,
        sameSite: 'lax',
        maxAge: tokens.expires_in || 300,
        path: '/',
      });
    }

    // Stocker aussi le temps d'expiration
    cookieStore.set('token_expires_at', String(Date.now() + (tokens.expires_in * 1000)), {
      httpOnly: true,
      secure: isProduction,
      sameSite: 'lax',
      maxAge: tokens.expires_in || 300,
      path: '/',
    });

    console.log('✅ Tokens stored in HttpOnly cookies');

    // Retourner une réponse de succès (sans les tokens)
    return NextResponse.json({
      success: true,
      message: 'Authentification réussie',
      expires_in: tokens.expires_in,
    });

  } catch (error) {
    console.error('❌ Error in token exchange API:', error);

    return NextResponse.json(
      {
        error: 'Erreur serveur',
        message: error instanceof Error ? error.message : 'Erreur inconnue'
      },
      { status: 500 }
    );
  }
}