<?php

namespace App\Http\Controllers\Auth;

use App\Http\Controllers\Controller;
use Illuminate\Http\RedirectResponse;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Auth;
use Illuminate\Support\Facades\RateLimiter;
use Illuminate\Validation\ValidationException;
use Illuminate\View\View;

/**
 * 管理员独立登录：与普通用户登录（/login）分离到不同页面。
 * 仅允许具备后台角色（isAdmin）的账户登录，其余账户直接拒绝。
 * 含图形验证码 + 10 分钟 5 次错误锁定的人机/防暴破管控。
 */
class AdminLoginController extends Controller
{
    protected const MAX_ATTEMPTS = 5;
    protected const DECAY_SECONDS = 600;

    public function show(): View
    {
        return view('auth.admin-login');
    }

    public function store(Request $request): RedirectResponse
    {
        $key = $this->throttleKey($request);

        if (RateLimiter::tooManyAttempts($key, self::MAX_ATTEMPTS)) {
            $seconds = RateLimiter::availableIn($key);
            $request->session()->forget('captcha');
            throw ValidationException::withMessages([
                'email' => '登录尝试过于频繁，出于安全考虑已临时锁定。请在约 '.ceil($seconds / 60).' 分钟（'.ceil($seconds).' 秒）后重试。',
            ]);
        }

        $data = $request->validate([
            'email' => ['required', 'email'],
            'password' => ['required', 'string'],
            'captcha' => ['required', 'string', function ($attribute, $value, $fail) use ($request) {
                if (strtolower(trim((string) $value)) !== strtolower((string) $request->session()->get('captcha', ''))) {
                    $fail('图形验证码不正确，请重新输入。');
                }
            }],
        ]);

        if (! Auth::attempt(['email' => $data['email'], 'password' => $data['password']], $request->boolean('remember'))) {
            RateLimiter::hit($key, self::DECAY_SECONDS);
            $attempts = RateLimiter::attempts($key);
            $left = max(0, self::MAX_ATTEMPTS - $attempts);
            $request->session()->forget('captcha');

            $msg = '账号或密码不正确。';
            if ($left > 0) {
                $msg .= "（已错误 {$attempts} 次，再错 {$left} 次将锁定 10 分钟）";
            } else {
                $msg .= '（错误次数过多，已锁定 10 分钟）';
            }

            return back()->withErrors([
                'email' => $msg,
            ])->onlyInput('email');
        }

        $user = Auth::user();

        if (! $user->isAdmin()) {
            Auth::logout();
            $request->session()->invalidate();
            $request->session()->regenerateToken();
            $request->session()->forget('captcha');

            return back()->withErrors([
                'email' => '该账户没有后台管理权限。',
            ])->onlyInput('email');
        }

        RateLimiter::clear($key);
        $request->session()->forget('captcha');
        $request->session()->regenerate();

        return redirect()->intended('/admin');
    }

    protected function throttleKey(Request $request): string
    {
        return 'admin-login:'.strtolower($request->input('email', '')).':'.$request->ip();
    }
}