package com.snp.batch.service;

import com.snp.batch.global.dto.BypassConfigRequest;
import com.snp.batch.global.dto.BypassConfigResponse;
import com.snp.batch.global.dto.BypassParamDto;
import com.snp.batch.global.model.BypassApiConfig;
import com.snp.batch.global.model.BypassApiParam;
import com.snp.batch.global.repository.BypassApiConfigRepository;
import jakarta.persistence.EntityManager;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

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

/**
 * BYPASS API 설정 CRUD 비즈니스 로직
 */
@Slf4j
@Service
@RequiredArgsConstructor
public class BypassConfigService {

    private final BypassApiConfigRepository configRepository;
    private final EntityManager entityManager;

    /**
     * 설정 목록 조회
     */
    public List<BypassConfigResponse> getConfigs() {
        return configRepository.findAll().stream()
                .map(this::toResponse)
                .toList();
    }

    /**
     * 설정 상세 조회
     */
    public BypassConfigResponse getConfig(Long id) {
        BypassApiConfig config = configRepository.findById(id)
                .orElseThrow(() -> new IllegalArgumentException("설정을 찾을 수 없습니다: " + id));
        return toResponse(config);
    }

    /**
     * 설정 등록
     */
    @Transactional
    public BypassConfigResponse createConfig(BypassConfigRequest request) {
        String endpointName = extractEndpointName(request.getExternalPath());
        if (configRepository.existsByDomainNameAndEndpointName(request.getDomainName(), endpointName)) {
            throw new IllegalArgumentException(
                    "이미 존재하는 도메인+엔드포인트 조합입니다: " + request.getDomainName() + "/" + endpointName);
        }
        BypassApiConfig config = toEntity(request);

        if (request.getParams() != null) {
            request.getParams().forEach(p -> {
                BypassApiParam param = toParamEntity(p);
                param.setConfig(config);
                config.getParams().add(param);
            });
        }
        return toResponse(configRepository.save(config));
    }

    /**
     * 설정 수정
     */
    @Transactional
    public BypassConfigResponse updateConfig(Long id, BypassConfigRequest request) {
        BypassApiConfig config = configRepository.findById(id)
                .orElseThrow(() -> new IllegalArgumentException("설정을 찾을 수 없습니다: " + id));

        config.setDomainName(request.getDomainName());
        config.setDisplayName(request.getDisplayName());
        config.setWebclientBean(request.getWebclientBean());
        config.setExternalPath(request.getExternalPath());
        config.setHttpMethod(request.getHttpMethod());
        config.setDescription(request.getDescription());

        // params 교체: clear → flush(DELETE 실행) → 새로 추가
        config.getParams().clear();
        entityManager.flush();

        if (request.getParams() != null) {
            request.getParams().forEach(p -> {
                BypassApiParam param = toParamEntity(p);
                param.setConfig(config);
                config.getParams().add(param);
            });
        }

        return toResponse(configRepository.save(config));
    }

    /**
     * 설정 삭제
     */
    @Transactional
    public void deleteConfig(Long id) {
        if (!configRepository.existsById(id)) {
            throw new IllegalArgumentException("설정을 찾을 수 없습니다: " + id);
        }
        configRepository.deleteById(id);
    }

    /**
     * 코드 생성 완료 마킹
     */
    @Transactional
    public void markAsGenerated(Long id) {
        BypassApiConfig config = configRepository.findById(id)
                .orElseThrow(() -> new IllegalArgumentException("설정을 찾을 수 없습니다: " + id));
        config.setGenerated(true);
        config.setGeneratedAt(LocalDateTime.now());
        configRepository.save(config);
    }

    // ---- private 헬퍼 메서드 ----

    private BypassConfigResponse toResponse(BypassApiConfig config) {
        return BypassConfigResponse.builder()
                .id(config.getId())
                .domainName(config.getDomainName())
                .endpointName(config.getEndpointName())
                .displayName(config.getDisplayName())
                .webclientBean(config.getWebclientBean())
                .externalPath(config.getExternalPath())
                .httpMethod(config.getHttpMethod())
                .description(config.getDescription())
                .generated(config.getGenerated())
                .generatedAt(config.getGeneratedAt())
                .createdAt(config.getCreatedAt())
                .updatedAt(config.getUpdatedAt())
                .params(config.getParams().stream().map(this::toParamDto).toList())
                .build();
    }

    private BypassApiConfig toEntity(BypassConfigRequest request) {
        return BypassApiConfig.builder()
                .domainName(request.getDomainName())
                .endpointName(extractEndpointName(request.getExternalPath()))
                .displayName(request.getDisplayName())
                .webclientBean(request.getWebclientBean())
                .externalPath(request.getExternalPath())
                .httpMethod(request.getHttpMethod() != null ? request.getHttpMethod() : "GET")
                .description(request.getDescription())
                .build();
    }

    /**
     * externalPath의 마지막 세그먼트를 endpointName으로 추출
     */
    private String extractEndpointName(String externalPath) {
        if (externalPath == null || externalPath.isEmpty()) {
            return "";
        }
        String[] segments = externalPath.split("/");
        return segments[segments.length - 1];
    }

    private BypassApiParam toParamEntity(BypassParamDto dto) {
        return BypassApiParam.builder()
                .paramName(dto.getParamName())
                .paramType(dto.getParamType() != null ? dto.getParamType() : "STRING")
                .paramIn(dto.getParamIn() != null ? dto.getParamIn() : "QUERY")
                .required(dto.getRequired() != null ? dto.getRequired() : true)
                .description(dto.getDescription())
                .sortOrder(dto.getSortOrder() != null ? dto.getSortOrder() : 0)
                .example(dto.getExample())
                .build();
    }

    private BypassParamDto toParamDto(BypassApiParam param) {
        return BypassParamDto.builder()
                .id(param.getId())
                .paramName(param.getParamName())
                .paramType(param.getParamType())
                .paramIn(param.getParamIn())
                .required(param.getRequired())
                .description(param.getDescription())
                .sortOrder(param.getSortOrder())
                .example(param.getExample())
                .build();
    }
}