<?php
declare (strict_types = 1);

namespace app\service;

/**
 * 用户服务类
 * 用于处理用户账号管理相关逻辑
 */
class UserService
{
    /**
     * 账号数据文件路径
     */
    private const USERS_FILE = 'users.json';
    
    /**
     * 管理员账号（固定）
     */
    private const ADMIN_USERNAME = 'admin';
    private const ADMIN_PASSWORD = '123456';
    
    /**
     * 初始化账号数据文件
     */
    private function initUsersFile(): void
    {
        $filePath = $this->getUsersFilePath();
        if (!file_exists($filePath)) {
            $dir = dirname($filePath);
            if (!is_dir($dir)) {
                mkdir($dir, 0755, true);
            }
            file_put_contents($filePath, json_encode([], JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE));
        }
    }
    
    /**
     * 获取账号数据文件路径
     * @return string
     */
    private function getUsersFilePath(): string
    {
        // 获取项目根目录
        $rootPath = dirname(dirname(__DIR__));
        $runtimePath = $rootPath . '/runtime';
        if (!is_dir($runtimePath)) {
            mkdir($runtimePath, 0755, true);
        }
        return $runtimePath . '/' . self::USERS_FILE;
    }
    
    /**
     * 读取所有账号
     * @return array
     */
    public function getAllUsers(): array
    {
        $this->initUsersFile();
        $filePath = $this->getUsersFilePath();
        $content = file_get_contents($filePath);
        $users = json_decode($content, true);
        return is_array($users) ? $users : [];
    }
    
    /**
     * 保存账号数据
     * @param array $users
     * @return bool
     */
    private function saveUsers(array $users): bool
    {
        $this->initUsersFile();
        $filePath = $this->getUsersFilePath();
        return file_put_contents($filePath, json_encode($users, JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE)) !== false;
    }
    
    /**
     * 验证登录（包括管理员和普通用户）
     * @param string $username
     * @param string $password
     * @return array|false 返回用户信息或false
     */
    public function verifyLogin(string $username, string $password)
    {
        // 验证管理员账号
        if ($username === self::ADMIN_USERNAME && $password === self::ADMIN_PASSWORD) {
            return [
                'username' => $username,
                'is_admin' => true,
            ];
        }
        
        // 验证普通用户账号
        $users = $this->getAllUsers();
        foreach ($users as $user) {
            if (isset($user['username']) && $user['username'] === $username) {
                if (isset($user['password']) && $user['password'] === $password) {
                    return [
                        'username' => $username,
                        'is_admin' => false,
                    ];
                }
            }
        }
        
        return false;
    }
    
    /**
     * 添加账号
     * @param string $username
     * @param string $password
     * @return array ['code' => 1|0, 'msg' => string]
     */
    public function addUser(string $username, string $password): array
    {
        if (empty($username) || empty($password)) {
            return ['code' => 0, 'msg' => '用户名和密码不能为空'];
        }
        
        if ($username === self::ADMIN_USERNAME) {
            return ['code' => 0, 'msg' => '不能添加管理员账号'];
        }
        
        $users = $this->getAllUsers();
        
        // 检查用户名是否已存在
        foreach ($users as $user) {
            if (isset($user['username']) && $user['username'] === $username) {
                return ['code' => 0, 'msg' => '用户名已存在'];
            }
        }
        
        // 添加新用户
        $users[] = [
            'username' => $username,
            'password' => $password,
            'created_at' => date('Y-m-d H:i:s'),
        ];
        
        if ($this->saveUsers($users)) {
            return ['code' => 1, 'msg' => '添加成功'];
        } else {
            return ['code' => 0, 'msg' => '保存失败'];
        }
    }
    
    /**
     * 删除账号
     * @param string $username
     * @return array ['code' => 1|0, 'msg' => string]
     */
    public function deleteUser(string $username): array
    {
        if ($username === self::ADMIN_USERNAME) {
            return ['code' => 0, 'msg' => '不能删除管理员账号'];
        }
        
        $users = $this->getAllUsers();
        $newUsers = [];
        
        foreach ($users as $user) {
            if (isset($user['username']) && $user['username'] !== $username) {
                $newUsers[] = $user;
            }
        }
        
        if (count($newUsers) === count($users)) {
            return ['code' => 0, 'msg' => '用户不存在'];
        }
        
        if ($this->saveUsers($newUsers)) {
            return ['code' => 1, 'msg' => '删除成功'];
        } else {
            return ['code' => 0, 'msg' => '保存失败'];
        }
    }
    
    /**
     * 检查是否为管理员
     * @param string $username
     * @return bool
     */
    public function isAdmin(string $username): bool
    {
        return $username === self::ADMIN_USERNAME;
    }
}