<?php

namespace App\Http\Controllers\Auth;

use App\Http\Controllers\Concerns\ProxiesBackend;
use App\Http\Controllers\Controller;
use App\Services\BackendHttpClient;
use Illuminate\Http\JsonResponse;
use Illuminate\Http\Request;

class AvailabilityController extends Controller
{
    use ProxiesBackend;

    public function __construct(private readonly BackendHttpClient $client)
    {
    }

    /**
     * Check availability for username or email during registration via upstream API.
     */
    public function __invoke(Request $request): JsonResponse
    {
        $field = $request->query('field');
        $value = (string) $request->query('value', '');

        if (!in_array($field, ['username', 'email'], true)) {
            return response()->json([
                'ok' => false,
                'error' => 'Unsupported field',
            ], 422);
        }

        // Basic format checks to reduce unnecessary upstream calls
        if ($field === 'username' && mb_strlen($value) < 3) {
            return response()->json(['ok' => true, 'available' => false, 'reason' => 'too_short']);
        }
        if ($field === 'email' && !filter_var($value, FILTER_VALIDATE_EMAIL)) {
            return response()->json(['ok' => true, 'available' => false, 'reason' => 'invalid_format']);
        }

        try {
            $res = $this->client->get($request, '/api/auth/availability', [
                'field' => $field,
                'value' => $value,
            ], retry: true);

            if ($res->successful()) {
                $j = $res->json() ?: [];
                // Normalize to { ok: true, available: bool, reason? }
                $available = $j['available'] ?? $j['is_available'] ?? null;
                if ($available !== null) {
                    $out = ['ok' => true, 'available' => (bool) $available];
                    if (isset($j['reason'])) {
                        $out['reason'] = $j['reason'];
                    }
                    return response()->json($out, 200);
                }
                // Fallback: pass-through
                return response()->json($j, 200);
            }
            if ($res->clientError()) return $this->mapClientError($res);
            if ($res->serverError()) return $this->mapServiceUnavailable($res);
            return $this->mapBadGateway();
        } catch (\Throwable $e) {
            return $this->mapBadGateway('API server not reachable');
        }
    }
}