package com.guwan.backend.config;

import com.guwan.backend.constant.SecurityConstants;
import com.guwan.backend.security.JwtAuthenticationFilter;
import lombok.RequiredArgsConstructor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.authentication.AuthenticationManager;
import org.springframework.security.config.annotation.authentication.configuration.AuthenticationConfiguration;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.annotation.web.configurers.AbstractHttpConfigurer;
import org.springframework.security.config.http.SessionCreationPolicy;
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
import org.springframework.security.crypto.password.PasswordEncoder;
import org.springframework.security.web.SecurityFilterChain;
import org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter;

/**
 * Spring Security 安全配置类
 * 配置安全相关的全局策略
 */
@Configuration
@EnableWebSecurity
@RequiredArgsConstructor
public class SecurityConfig {

    private final JwtAuthenticationFilter jwtAuthFilter;

    /**
     * 配置安全过滤链
     * 定义了系统的安全策略，包括：
     * 1. CSRF 和 CORS 配置
     * 2. Session 管理策略
     * 3. 请求授权规则
     * 4. JWT 过滤器配置
     */
    @Bean
    public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
        http
            .csrf(AbstractHttpConfigurer::disable)      // 禁用CSRF保护
            .cors(AbstractHttpConfigurer::disable)      // 禁用CORS保护
            .sessionManagement(session -> 
                session.sessionCreationPolicy(SessionCreationPolicy.STATELESS))  // 使用无状态会话
            .authorizeHttpRequests(auth -> auth
                .requestMatchers(SecurityConstants.WHITE_LIST.toArray(new String[0])).permitAll()        // 配置API白名单
                .requestMatchers(SecurityConstants.STATIC_RESOURCES.toArray(new String[0])).permitAll()  // 配置静态资源白名单
                .anyRequest().authenticated()  // 其他所有请求都需要认证
            )
            .addFilterBefore(jwtAuthFilter, UsernamePasswordAuthenticationFilter.class);  // 添加JWT过滤器

        return http.build();
    }

    /**
     * 认证管理器
     */
    @Bean
    public AuthenticationManager authenticationManager(AuthenticationConfiguration config) throws Exception {
        return config.getAuthenticationManager();
    }

    /**
     * 密码编码器
     * 使用 BCrypt 加密算法
     */
    @Bean
    public PasswordEncoder passwordEncoder() {
        return new BCryptPasswordEncoder();
    }
}