package services

import (
	"errors"
	"platform/pkg/u"
	"platform/web/core"
	m "platform/web/models"
	q "platform/web/queries"

	"gorm.io/gorm"
)

var Area = &areaService{}

type areaService struct{}

func (s *areaService) ListAreas() ([]*m.Area, error) {
	areas, err := q.Area.
		Order(q.Area.Level, q.Area.ParentID, q.Area.ID).
		Find()
	if err != nil {
		return nil, core.NewServErr("查询地区失败", err)
	}
	return areas, nil
}

func (s *areaService) FindIdByFilter(prov *string, city *string) (*int32, error) {
	prov = u.N(prov)
	city = u.N(city)
	if prov == nil && city == nil {
		return nil, nil
	}

	switch {
	case prov != nil && city == nil:
		area, err := q.Area.
			Where(
				q.Area.Level.Eq(int(m.AreaLevelProvince)),
				q.Area.Name.Eq(*prov),
			).
			Order(q.Area.ID).
			Take()
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, ErrAreaNotExist
		}
		if err != nil {
			return nil, core.NewServErr("查询地区失败", err)
		}
		return u.P(area.ID), nil
	case prov == nil && city != nil:
		area, err := q.Area.
			Where(
				q.Area.Level.Eq(int(m.AreaLevelCity)),
				q.Area.Name.Eq(*city),
			).
			Order(q.Area.ID).
			Take()
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, ErrAreaNotExist
		}
		if err != nil {
			return nil, core.NewServErr("查询地区失败", err)
		}
		return u.P(area.ID), nil
	default:
		province, err := q.Area.
			Where(
				q.Area.Level.Eq(int(m.AreaLevelProvince)),
				q.Area.Name.Eq(*prov),
			).
			Order(q.Area.ID).
			Take()
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, ErrAreaNotExist
		}
		if err != nil {
			return nil, core.NewServErr("查询地区失败", err)
		}

		area, err := q.Area.
			Where(
				q.Area.ParentID.Eq(province.ID),
				q.Area.Level.Eq(int(m.AreaLevelCity)),
				q.Area.Name.Eq(*city),
			).
			Order(q.Area.ID).
			Take()
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, ErrAreaNotExist
		}
		if err != nil {
			return nil, core.NewServErr("查询地区失败", err)
		}
		return u.P(area.ID), nil
	}
}

func (s *areaService) Get(id int32) (*m.Area, error) {
	area, err := q.Area.
		Preload(q.Area.Parent).
		Where(q.Area.ID.Eq(id)).
		Take()
	if errors.Is(err, gorm.ErrRecordNotFound) {
		return nil, ErrAreaNotExist
	}
	if err != nil {
		return nil, core.NewServErr("查询地区失败", err)
	}
	return area, nil
}

var ErrAreaNotExist = core.NewBizErr("地区不存在")