package com.label.service;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.label.common.exception.BusinessException;
import com.label.common.result.PageResult;
import com.label.entity.SysCompany;
import com.label.mapper.SysCompanyMapper;
import com.label.mapper.SysUserMapper;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

@Slf4j
@Service
@RequiredArgsConstructor
public class CompanyService {

    private final SysCompanyMapper companyMapper;
    private final SysUserMapper userMapper;

    public PageResult<SysCompany> list(int page, int pageSize, String status) {
        pageSize = Math.min(pageSize, 100);
        LambdaQueryWrapper<SysCompany> wrapper = new LambdaQueryWrapper<SysCompany>()
                .orderByDesc(SysCompany::getCreatedAt);
        if (status != null && !status.isBlank()) {
            wrapper.eq(SysCompany::getStatus, status);
        }

        Page<SysCompany> result = companyMapper.selectPage(new Page<>(page, pageSize), wrapper);
        return PageResult.of(result.getRecords(), result.getTotal(), page, pageSize);
    }

    @Transactional
    public SysCompany create(String companyName, String companyCode) {
        String normalizedName = requireText(companyName, "公司名称不能为空");
        String normalizedCode = normalizeCode(companyCode);

        ensureUniqueCode(null, normalizedCode);
        ensureUniqueName(null, normalizedName);

        SysCompany company = new SysCompany();
        company.setCompanyName(normalizedName);
        company.setCompanyCode(normalizedCode);
        company.setStatus("ACTIVE");
        companyMapper.insert(company);
        log.info("公司已创建: id={}, code={}", company.getId(), normalizedCode);
        return company;
    }

    @Transactional
    public SysCompany update(Long companyId, String companyName, String companyCode) {
        SysCompany company = getExistingCompany(companyId);
        String normalizedName = requireText(companyName, "公司名称不能为空");
        String normalizedCode = normalizeCode(companyCode);

        ensureUniqueCode(companyId, normalizedCode);
        ensureUniqueName(companyId, normalizedName);

        company.setCompanyName(normalizedName);
        company.setCompanyCode(normalizedCode);
        companyMapper.updateById(company);
        return company;
    }

    @Transactional
    public void updateStatus(Long companyId, String status) {
        SysCompany company = getExistingCompany(companyId);
        if (!"ACTIVE".equals(status) && !"DISABLED".equals(status)) {
            throw new BusinessException("INVALID_COMPANY_STATUS", "公司状态不合法", HttpStatus.BAD_REQUEST);
        }
        company.setStatus(status);
        companyMapper.updateById(company);
    }

    @Transactional
    public void delete(Long companyId) {
        getExistingCompany(companyId);
        Long userCount = userMapper.countByCompanyId(companyId);
        if (userCount != null && userCount > 0) {
            throw new BusinessException("COMPANY_HAS_USERS", "公司下仍存在用户，无法删除", HttpStatus.CONFLICT);
        }
        companyMapper.deleteById(companyId);
    }

    private SysCompany getExistingCompany(Long companyId) {
        SysCompany company = companyMapper.selectById(companyId);
        if (company == null) {
            throw new BusinessException("NOT_FOUND", "公司不存在: " + companyId, HttpStatus.NOT_FOUND);
        }
        return company;
    }

    private void ensureUniqueCode(Long companyId, String companyCode) {
        SysCompany existing = companyMapper.selectByCompanyCode(companyCode);
        if (existing != null && !existing.getId().equals(companyId)) {
            throw new BusinessException("DUPLICATE_COMPANY_CODE", "公司代码已存在", HttpStatus.CONFLICT);
        }
    }

    private void ensureUniqueName(Long companyId, String companyName) {
        SysCompany existing = companyMapper.selectOne(new LambdaQueryWrapper<SysCompany>()
                .eq(SysCompany::getCompanyName, companyName)
                .last("LIMIT 1"));
        if (existing != null && !existing.getId().equals(companyId)) {
            throw new BusinessException("DUPLICATE_COMPANY_NAME", "公司名称已存在", HttpStatus.CONFLICT);
        }
    }

    private String requireText(String text, String message) {
        if (text == null || text.isBlank()) {
            throw new BusinessException("INVALID_COMPANY_FIELD", message, HttpStatus.BAD_REQUEST);
        }
        return text.trim();
    }

    private String normalizeCode(String companyCode) {
        return requireText(companyCode, "公司代码不能为空").toUpperCase();
    }
}