package com.gcsc.guide.config;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.gcsc.guide.auth.JwtAuthenticationFilter;
import jakarta.servlet.http.HttpServletResponse;
import lombok.RequiredArgsConstructor;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.MediaType;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.http.SessionCreationPolicy;
import org.springframework.security.web.SecurityFilterChain;
import org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter;
import org.springframework.web.cors.CorsConfiguration;
import org.springframework.web.cors.CorsConfigurationSource;
import org.springframework.web.cors.UrlBasedCorsConfigurationSource;

import java.time.LocalDateTime;
import java.util.List;
import java.util.Map;

@Configuration
@EnableWebSecurity
@RequiredArgsConstructor
public class SecurityConfig {

    private final JwtAuthenticationFilter jwtAuthenticationFilter;
    private final ObjectMapper objectMapper;

    @Value("${app.cors.allowed-origins:http://localhost:5173,https://guide.gc-si.dev}")
    private List<String> allowedOrigins;

    @Bean
    public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
        http
            .cors(cors -> cors.configurationSource(corsConfigurationSource()))
            .csrf(csrf -> csrf.disable())
            .sessionManagement(session ->
                session.sessionCreationPolicy(SessionCreationPolicy.STATELESS))
            .authorizeHttpRequests(auth -> auth
                .requestMatchers(
                    "/api/auth/**",
                    "/api/health",
                    "/actuator/health",
                    "/h2-console/**",
                    "/swagger-ui/**",
                    "/swagger-ui.html",
                    "/v3/api-docs/**"
                ).permitAll()
                .requestMatchers("/api/admin/**").authenticated()
                .anyRequest().authenticated()
            )
            .exceptionHandling(ex -> ex
                .authenticationEntryPoint((request, response, authException) -> {
                    response.setStatus(HttpServletResponse.SC_UNAUTHORIZED);
                    response.setContentType(MediaType.APPLICATION_JSON_VALUE);
                    response.setCharacterEncoding("UTF-8");
                    objectMapper.writeValue(response.getOutputStream(), Map.of(
                        "status", 401,
                        "error", "Unauthorized",
                        "message", "인증이 필요합니다. JWT 토큰을 Authorization 헤더에 포함하세요.",
                        "timestamp", LocalDateTime.now().toString()
                    ));
                })
                .accessDeniedHandler((request, response, accessDeniedException) -> {
                    response.setStatus(HttpServletResponse.SC_FORBIDDEN);
                    response.setContentType(MediaType.APPLICATION_JSON_VALUE);
                    response.setCharacterEncoding("UTF-8");
                    objectMapper.writeValue(response.getOutputStream(), Map.of(
                        "status", 403,
                        "error", "Forbidden",
                        "message", "접근 권한이 없습니다.",
                        "timestamp", LocalDateTime.now().toString()
                    ));
                })
            )
            .headers(headers -> headers.frameOptions(frame -> frame.sameOrigin()))
            .addFilterBefore(jwtAuthenticationFilter, UsernamePasswordAuthenticationFilter.class);

        return http.build();
    }

    @Bean
    public CorsConfigurationSource corsConfigurationSource() {
        CorsConfiguration config = new CorsConfiguration();
        config.setAllowedOrigins(allowedOrigins);
        config.setAllowedMethods(List.of("GET", "POST", "PUT", "DELETE", "OPTIONS"));
        config.setAllowedHeaders(List.of("*"));
        config.setExposedHeaders(List.of("Authorization"));
        config.setAllowCredentials(true);
        config.setMaxAge(3600L);

        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        source.registerCorsConfiguration("/**", config);
        return source;
    }
}