/**
 * QBO OAuth2 Authorization
 * GET  /api/qbo/auth          — redirect to Intuit authorization page
 * GET  /api/qbo/auth/callback — exchange code for tokens
 */

import { NextRequest, NextResponse } from 'next/server';
import { QboClient } from '@/lib/services/qbo-client';

export async function GET(request: NextRequest) {
  const { searchParams } = request.nextUrl;
  const code = searchParams.get('code');
  const realmId = searchParams.get('realmId');
  const error = searchParams.get('error');

  const redirectUri = `${process.env.NEXTAUTH_URL}/api/qbo/auth`;

  // ── Callback from Intuit ──────────────────────────────────────────────────
  const baseUrl = process.env.NEXTAUTH_URL || 'https://pulse.wulfconsulting.cloud';

  if (code && realmId) {
    try {
      const client = new QboClient();
      await client.exchangeCodeForToken(code, redirectUri);
      console.log(`[QBO Auth] Tokens saved for realm ${realmId}`);
      return NextResponse.redirect(`${baseUrl}/admin/qbo?connected=true`);
    } catch (err) {
      const msg = err instanceof Error ? err.message : String(err);
      console.error('[QBO Auth] Token exchange failed:', msg);
      return NextResponse.redirect(`${baseUrl}/admin/qbo?error=${encodeURIComponent(msg)}`);
    }
  }

  if (error) {
    return NextResponse.redirect(`${baseUrl}/admin/qbo?error=${encodeURIComponent(error)}`);
  }

  // ── Initiate authorization ────────────────────────────────────────────────
  try {
    const client = new QboClient();
    const state = Math.random().toString(36).slice(2);
    const authUrl = client.getAuthorizationUrl(redirectUri, state);
    return NextResponse.redirect(authUrl);
  } catch (err) {
    const msg = err instanceof Error ? err.message : String(err);
    return NextResponse.json({ error: msg }, { status: 500 });
  }
}