import { NextRequest, NextResponse } from 'next/server';
import { auth } from '@/auth';
import { getEffectiveTier } from '@/lib/entitlements';
import { isByokProviderAllowed } from '@/lib/byok';
import { fetchLiveModelsForProvider, type FetchModelsResult } from '@/lib/ai/models-list';
import { VALID_PROVIDERS, type AiGatewayProvider } from '@/lib/ai/router';

/**
 * GET /api/user/api-keys/verify?provider=<provider>&key=<api_key>&baseUrl=<optional_custom_url>
 *
 * Verifies that the user's API key is valid by attempting to fetch models.
 * Returns validity status and available models if successful.
 *
 * Key is only considered VALID if we can fetch models from the actual provider API.
 * Fallback to hardcoded suggestions is NOT considered valid verification.
 */
export async function GET(request: NextRequest) {
  const session = await auth();
  if (!session?.user?.id) {
    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
  }

  const tier = await getEffectiveTier(session.user.id);
  if (tier === 'BASIC') {
    return NextResponse.json({ error: 'Forbidden' }, { status: 403 });
  }

  const { searchParams } = request.nextUrl;
  const provider = searchParams.get('provider') as AiGatewayProvider;
  const apiKey = searchParams.get('key');
  const baseUrl = searchParams.get('baseUrl') ?? undefined;

  if (!provider || !apiKey) {
    return NextResponse.json({ error: 'Missing parameters' }, { status: 400 });
  }

  if (!VALID_PROVIDERS.has(provider)) {
    return NextResponse.json({ error: 'Invalid provider' }, { status: 400 });
  }

  if (!isByokProviderAllowed(tier, provider)) {
    return NextResponse.json({ error: 'Tier restricted' }, { status: 403 });
  }

  try {
    const result: FetchModelsResult = await fetchLiveModelsForProvider(provider, apiKey, baseUrl);

    console.log(`[verify] ${provider}: fromApi=${result.fromApi}, models=${result.models.length}`, result.models);

    // Only consider key valid if we got models from the REAL API (not fallbacks)
    // Exception: Anthropic/Google/custom don't guarantee public /models endpoints, so we accept fallbacks for them
    const acceptsFallbacks =
      provider === 'anthropic' ||
      provider === 'anthropic_custom' ||
      provider === 'custom_anthropic' ||
      provider === 'google' ||
      provider === 'minimax' ||
      provider === 'custom' ||
      provider === 'custom_openai';
    const isValid = result.models.length > 0 && (result.fromApi || acceptsFallbacks);

    return NextResponse.json({
      valid: isValid,
      models: result.models,
      fromApi: result.fromApi,
      message: isValid
        ? result.fromApi
          ? `${result.models.length} modèle(s) trouvé(s) via l'API ${provider}`
          : `${result.models.length} modèle(s) suggéré(s) pour ${provider}`
        : 'Aucun modèle trouvé - vérifiez votre clé API'
    });
  } catch (error) {
    const message = error instanceof Error ? error.message : 'Clé API invalide';
    console.error(`[verify] ${provider} failed:`, error);
    return NextResponse.json({
      valid: false,
      models: [],
      fromApi: false,
      message
    }, { status: 200 }); // Return 200 with valid:false for UI handling
  }
}