package com.ruoyi.system.service.impl;

import com.ruoyi.common.exception.ServiceException;
import com.ruoyi.common.utils.StringUtils;
import com.ruoyi.system.domain.SysVisitArea;
import com.ruoyi.system.dto.SysVisitAreaAddRequest;
import com.ruoyi.system.dto.SysVisitAreaDeleteRequest;
import com.ruoyi.system.dto.SysVisitAreaDetailRequest;
import com.ruoyi.system.dto.SysVisitAreaEditRequest;
import com.ruoyi.system.dto.SysVisitAreaTreeRequest;
import com.ruoyi.system.mapper.SysVisitAreaMapper;
import com.ruoyi.system.service.ISysVisitAreaService;
import com.ruoyi.system.vo.SysVisitAreaVO;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.util.CollectionUtils;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Objects;
import java.util.stream.Collectors;

/**
 * 访问区域服务实现
 *
 * @author ruoyi
 */
@Service
public class SysVisitAreaServiceImpl implements ISysVisitAreaService
{
    @Autowired
    private SysVisitAreaMapper visitAreaMapper;

    @Override
    public List<SysVisitAreaVO> tree(SysVisitAreaTreeRequest request)
    {
        SysVisitAreaTreeRequest query = request == null ? new SysVisitAreaTreeRequest() : request;
        query.setAreaName(StringUtils.trim(query.getAreaName()));
        return buildTree(visitAreaMapper.selectAreaTreeList(query));
    }

    @Override
    public SysVisitAreaVO detail(SysVisitAreaDetailRequest request)
    {
        Long areaId = getRequiredAreaId(request == null ? null : request.getAreaId());
        SysVisitAreaVO detail = visitAreaMapper.selectVoById(areaId);
        if (detail == null)
        {
            throw new ServiceException("访问区域不存在");
        }
        return detail;
    }

    @Override
    public int add(SysVisitAreaAddRequest request, String username)
    {
        if (request == null)
        {
            throw new ServiceException("访问区域内容不能为空");
        }
        Long parentId = getParentId(request.getParentId());
        SysVisitArea parent = getParentArea(parentId);
        String areaName = getRequiredAreaName(request.getAreaName());
        String areaCode = trimToNull(request.getAreaCode());
        checkUnique(areaName, areaCode, parentId, null);

        SysVisitArea area = new SysVisitArea();
        area.setParentId(parentId);
        area.setAncestors(getAncestors(parent));
        area.setAreaCode(areaCode);
        area.setAreaName(areaName);
        area.setAreaDesc(StringUtils.trim(request.getAreaDesc()));
        area.setOrderNum(request.getOrderNum() == null ? 0 : request.getOrderNum());
        area.setCreateBy(username);
        return visitAreaMapper.insertArea(area);
    }

    @Override
    public int edit(SysVisitAreaEditRequest request, String username)
    {
        if (request == null)
        {
            throw new ServiceException("访问区域内容不能为空");
        }
        Long areaId = getRequiredAreaId(request.getAreaId());
        SysVisitArea oldArea = visitAreaMapper.selectById(areaId);
        if (oldArea == null)
        {
            throw new ServiceException("访问区域不存在");
        }

        Long parentId = getParentId(request.getParentId());
        if (Objects.equals(areaId, parentId))
        {
            throw new ServiceException("上级区域不能选择自身");
        }
        SysVisitArea parent = getParentArea(parentId);
        if (parent != null && containsAncestor(parent.getAncestors(), areaId))
        {
            throw new ServiceException("上级区域不能选择当前区域的下级");
        }

        String areaName = getRequiredAreaName(request.getAreaName());
        String areaCode = trimToNull(request.getAreaCode());
        checkUnique(areaName, areaCode, parentId, areaId);

        String newAncestors = getAncestors(parent);
        SysVisitArea area = new SysVisitArea();
        area.setAreaId(areaId);
        area.setParentId(parentId);
        area.setAncestors(newAncestors);
        area.setAreaCode(areaCode);
        area.setAreaName(areaName);
        area.setAreaDesc(StringUtils.trim(request.getAreaDesc()));
        area.setOrderNum(request.getOrderNum() == null ? 0 : request.getOrderNum());
        area.setUpdateBy(username);
        int rows = visitAreaMapper.updateArea(area);

        String oldChildAncestors = appendAncestor(oldArea.getAncestors(), areaId);
        String newChildAncestors = appendAncestor(newAncestors, areaId);
        if (!Objects.equals(oldChildAncestors, newChildAncestors))
        {
            visitAreaMapper.updateChildrenAncestors(areaId, oldChildAncestors, newChildAncestors);
        }
        return rows;
    }

    @Override
    public int delete(SysVisitAreaDeleteRequest request, String username)
    {
        if (request == null || CollectionUtils.isEmpty(request.getAreaIds()))
        {
            throw new ServiceException("区域主键集合不能为空");
        }
        for (Long areaId : request.getAreaIds())
        {
            getRequiredAreaId(areaId);
        }
        return visitAreaMapper.deleteByIds(request.getAreaIds(), username);
    }

    /**
     * 构建前端所需区域树。
     */
    private List<SysVisitAreaVO> buildTree(List<SysVisitAreaVO> areas)
    {
        List<SysVisitAreaVO> returnList = new ArrayList<SysVisitAreaVO>();
        List<Long> tempList = areas.stream().map(SysVisitAreaVO::getAreaId).collect(Collectors.toList());
        for (SysVisitAreaVO area : areas)
        {
            if (area.getParentId() == null || area.getParentId() == 0 || !tempList.contains(area.getParentId()))
            {
                recursionFn(areas, area);
                returnList.add(area);
            }
        }
        if (returnList.isEmpty())
        {
            returnList = areas;
        }
        return returnList;
    }

    private void recursionFn(List<SysVisitAreaVO> list, SysVisitAreaVO area)
    {
        List<SysVisitAreaVO> childList = getChildList(list, area);
        area.setChildren(childList);
        for (SysVisitAreaVO child : childList)
        {
            if (!getChildList(list, child).isEmpty())
            {
                recursionFn(list, child);
            }
        }
    }

    private List<SysVisitAreaVO> getChildList(List<SysVisitAreaVO> list, SysVisitAreaVO area)
    {
        List<SysVisitAreaVO> result = new ArrayList<SysVisitAreaVO>();
        Iterator<SysVisitAreaVO> it = list.iterator();
        while (it.hasNext())
        {
            SysVisitAreaVO current = it.next();
            if (current.getParentId() != null && current.getParentId().longValue() == area.getAreaId().longValue())
            {
                result.add(current);
            }
        }
        return result;
    }

    private Long getRequiredAreaId(Long areaId)
    {
        if (areaId == null || areaId <= 0)
        {
            throw new ServiceException("区域主键不能为空");
        }
        return areaId;
    }

    private Long getParentId(Long parentId)
    {
        if (parentId == null)
        {
            return 0L;
        }
        if (parentId < 0)
        {
            throw new ServiceException("上级区域不正确");
        }
        return parentId;
    }

    private SysVisitArea getParentArea(Long parentId)
    {
        if (parentId == 0)
        {
            return null;
        }
        SysVisitArea parent = visitAreaMapper.selectById(parentId);
        if (parent == null)
        {
            throw new ServiceException("上级区域不存在");
        }
        return parent;
    }

    private String getRequiredAreaName(String areaName)
    {
        String value = StringUtils.trim(areaName);
        if (StringUtils.isEmpty(value))
        {
            throw new ServiceException("区域名称不能为空");
        }
        return value;
    }

    private String trimToNull(String value)
    {
        String result = StringUtils.trim(value);
        return StringUtils.isEmpty(result) ? null : result;
    }

    private void checkUnique(String areaName, String areaCode, Long parentId, Long excludeAreaId)
    {
        if (visitAreaMapper.checkAreaNameUnique(areaName, parentId, excludeAreaId) != null)
        {
            throw new ServiceException("同级区域名称已存在");
        }
        if (StringUtils.isNotEmpty(areaCode) && visitAreaMapper.checkAreaCodeUnique(areaCode, excludeAreaId) != null)
        {
            throw new ServiceException("区域编码已存在");
        }
    }

    private String getAncestors(SysVisitArea parent)
    {
        if (parent == null)
        {
            return "0";
        }
        return appendAncestor(parent.getAncestors(), parent.getAreaId());
    }

    private String appendAncestor(String ancestors, Long areaId)
    {
        String prefix = StringUtils.isEmpty(ancestors) ? "0" : ancestors;
        return prefix + "," + areaId;
    }

    private boolean containsAncestor(String ancestors, Long areaId)
    {
        if (StringUtils.isEmpty(ancestors) || areaId == null)
        {
            return false;
        }
        String target = String.valueOf(areaId);
        for (String ancestor : ancestors.split(","))
        {
            if (target.equals(ancestor))
            {
                return true;
            }
        }
        return false;
    }
}