<?php

namespace App\Module\OAuth\Controllers;

use App\Http\Controllers\Controller;
use App\Module\OAuth\Services\OAuth;
use App\Module\User\Models\User;
use Illuminate\Http\Request;
use Illuminate\Http\JsonResponse;
use Illuminate\Support\Facades\Hash;


class TokenController extends Controller
{
    /**
     * 令牌端点
     */
    public function token(Request $request): JsonResponse
    {
        // 验证请求参数
        $request->validate([
            'grant_type' => 'required|in:authorization_code,password,client_credentials,refresh_token',
            'client_id' => 'required|string',
            'client_secret' => 'required|string',
        ]);

        // 验证客户端
        if (!OAuth::validateClient($request->client_id, $request->client_secret, $request->grant_type)) {
            return response()->json([
                'error' => 'invalid_client',
                'error_description' => '无效的客户端凭证'
            ], 401);
        }

        // 根据授权类型处理
        switch ($request->grant_type) {
            case 'authorization_code':
                return $this->handleAuthorizationCode($request);
            case 'password':
                return $this->handlePassword($request);
            case 'client_credentials':
                return $this->handleClientCredentials($request);
            case 'refresh_token':
                return $this->handleRefreshToken($request);
        }
    }

    /**
     * 处理授权码模式
     */
    protected function handleAuthorizationCode(Request $request): JsonResponse
    {
        $request->validate([
            'code' => 'required|string',
            'redirect_uri' => 'required|url'
        ]);

        // 获取并验证授权码
        $codeKey = 'oauth_auth_code:' . $request->code;
        $codeData = cache()->get($codeKey);

        if (!$codeData) {
            return response()->json([
                'error' => 'invalid_grant',
                'error_description' => '无效的授权码'
            ], 400);
        }

        // 验证客户端ID和回调地址
        if ($codeData['client_id'] !== $request->client_id ||
            $codeData['redirect_uri'] !== $request->redirect_uri) {
            return response()->json([
                'error' => 'invalid_grant',
                'error_description' => '授权码验证失败'
            ], 400);
        }

        // 删除使用过的授权码
        cache()->delete($codeKey);

        // 创建访问令牌
        $token = OAuth::createAccessToken(
            $request->client_id,
            $codeData['user_id'],
            $codeData['scope'] ? explode(' ', $codeData['scope']) : []
        );

        return $this->tokenResponse($token);
    }

    /**
     * 处理密码模式
     */
    protected function handlePassword(Request $request): JsonResponse
    {
        $request->validate([
            'username' => 'required|string',
            'password' => 'required|string',
            'scope' => 'nullable|string'
        ]);

        // 验证用户凭证
        $user = User::query()->where('email', $request->username)->first();
        if (!$user || !Hash::check($request->password, $user->password)) {
            return response()->json([
                'error' => 'invalid_grant',
                'error_description' => '无效的用户凭证'
            ], 400);
        }

        // 创建访问令牌
        $token = OAuth::createAccessToken(
            $request->client_id,
            $user->id,
            $request->scope ? explode(' ', $request->scope) : []
        );

        return $this->tokenResponse($token);
    }

    /**
     * 处理客户端模式
     */
    protected function handleClientCredentials(Request $request): JsonResponse
    {
        $request->validate([
            'scope' => 'nullable|string'
        ]);

        // 创建访问令牌（不关联用户）
        $token = OAuth::createAccessToken(
            $request->client_id,
            null,
            $request->scope ? explode(' ', $request->scope) : []
        );

        return $this->tokenResponse($token);
    }

    /**
     * 处理刷新令牌
     */
    protected function handleRefreshToken(Request $request): JsonResponse
    {
        $request->validate([
            'refresh_token' => 'required|string'
        ]);

        // TODO: 实现刷新令牌逻辑
        return response()->json([
            'error' => 'unsupported_grant_type',
            'error_description' => '暂不支持刷新令牌'
        ], 400);
    }

    /**
     * 格式化令牌响应
     */
    protected function tokenResponse($token): JsonResponse
    {
        return response()->json([
            'access_token' => $token->access_token,
            'token_type' => 'Bearer',
            'expires_in' => $token->expires_at->diffInSeconds(now()),
            'scope' => implode(' ', $token->scope ?? []),
        ]);
    }
}