package parking

import (
	"errors"
	"wails-app/internal/dao"
	"wails-app/internal/global"
	"wails-app/internal/model/parking/request"

	"gorm.io/gorm"
)

type parkingLotService struct{}

func NewParkingLotService() *parkingLotService {
	return &parkingLotService{}
}

// CreateParkingLot 创建停车区域
func (s *parkingLotService) CreateParkingLot(req request.ParkingLotCreate) error {
	// 检查区域编码是否已存在
	var existingLot dao.ParkingLot
	result := global.GVA_DB.Where("lot_code = ?", req.LotCode).First(&existingLot)
	if result.RowsAffected > 0 {
		return errors.New("区域编码已存在")
	}

	return global.GVA_DB.Transaction(func(tx *gorm.DB) error {
		lot := dao.ParkingLot{
			LotCode:     req.LotCode,
			LotName:     req.LotName,
			Capacity:    req.Capacity,
			Occupied:    0,
			Available:   req.Capacity,
			Description: req.Description,
		}
		if err := tx.Create(&lot).Error; err != nil {
			return err
		}
		// 显式更新布尔值，确保 false 不会被 GORM 的数据库默认值覆盖。
		return tx.Model(&lot).Updates(map[string]interface{}{
			"allow_temporary_when_full": req.AllowTemporaryWhenFull,
			"allow_monthly_when_full":   req.AllowMonthlyWhenFull,
			"allow_vip_when_full":       req.AllowVIPWhenFull,
		}).Error
	})
}

// UpdateParkingLot 更新停车区域
func (s *parkingLotService) UpdateParkingLot(req request.ParkingLotUpdate) error {
	return global.GVA_DB.Transaction(func(tx *gorm.DB) error {
		var lot dao.ParkingLot
		if err := tx.First(&lot, req.ID).Error; err != nil {
			if errors.Is(err, gorm.ErrRecordNotFound) {
				return errors.New("停车区域不存在")
			}
			return err
		}

		var duplicateCount int64
		if err := tx.Model(&dao.ParkingLot{}).
			Where("lot_code = ? AND id != ?", req.LotCode, req.ID).
			Count(&duplicateCount).Error; err != nil {
			return err
		}
		if duplicateCount > 0 {
			return errors.New("区域编码已被其他区域使用")
		}

		var occupied int64
		if err := tx.Model(&dao.VehicleRecord{}).
			Where("parking_lot_id = ? AND exit_time IS NULL", req.ID).
			Count(&occupied).Error; err != nil {
			return err
		}
		if int64(req.Capacity) < occupied {
			return errors.New("停车场容量不能小于当前在场车辆数")
		}

		return tx.Model(&lot).Updates(map[string]interface{}{
			"lot_code":                  req.LotCode,
			"lot_name":                  req.LotName,
			"capacity":                  req.Capacity,
			"occupied":                  occupied,
			"available":                 int64(req.Capacity) - occupied,
			"allow_temporary_when_full": req.AllowTemporaryWhenFull,
			"allow_monthly_when_full":   req.AllowMonthlyWhenFull,
			"allow_vip_when_full":       req.AllowVIPWhenFull,
			"description":               req.Description,
		}).Error
	})
}

// GetParkingLotByID 根据ID获取停车区域
func (s *parkingLotService) GetParkingLotByID(id uint) (dao.ParkingLot, error) {
	var lot dao.ParkingLot
	result := global.GVA_DB.First(&lot, id)
	if result.RowsAffected == 0 {
		return dao.ParkingLot{}, errors.New("停车区域不存在")
	}
	return lot, nil
}

// GetParkingLotByCode 根据编码获取停车区域
func (s *parkingLotService) GetParkingLotByCode(code string) (dao.ParkingLot, error) {
	var lot dao.ParkingLot
	result := global.GVA_DB.Where("lot_code = ?", code).First(&lot)
	if result.RowsAffected == 0 {
		return dao.ParkingLot{}, errors.New("停车区域不存在")
	}
	return lot, nil
}

func (s *parkingLotService) QueryAllParkingLots() ([]dao.ParkingLot, error) {
	var parkingLots []dao.ParkingLot
	err := global.GVA_DB.Find(&parkingLots).Error

	if err != nil {
		return parkingLots, err
	}

	return parkingLots, nil
}

// ListParkingLots 获取停车区域列表
func (s *parkingLotService) ListParkingLots(req request.ParkingLotQuery) (int64, []dao.ParkingLot, error) {
	var lots []dao.ParkingLot
	var total int64

	query := global.GVA_DB.Model(&dao.ParkingLot{})

	if req.LotCode != "" {
		query = query.Where("lot_code LIKE ?", "%"+req.LotCode+"%")
	}

	if req.LotId > 0 {
		query = query.Where("id = ?", req.LotId)
	}

	if req.LotName != "" {
		query = query.Where("lot_name LIKE ?", "%"+req.LotName+"%")
	}

	// 计算总数
	query.Count(&total)

	// 分页查询
	offset := (req.Page - 1) * req.PageSize
	result := query.Offset(offset).Limit(req.PageSize).Preload("Booths").Preload("Channels").Preload("UHFReaders").Find(&lots)
	if result.Error != nil {
		return 0, nil, result.Error
	}

	return total, lots, nil
}

// DeleteParkingLot 删除停车区域
func (s *parkingLotService) DeleteParkingLot(id uint) error {
	return global.GVA_DB.Transaction(func(tx *gorm.DB) error {
		var lot dao.ParkingLot
		if err := tx.First(&lot, id).Error; err != nil {
			if errors.Is(err, gorm.ErrRecordNotFound) {
				return errors.New("停车区域不存在")
			}
			return err
		}

		var activeSessions int64
		if err := tx.Model(&dao.VehicleRecord{}).
			Where("parking_lot_id = ? AND exit_time IS NULL", id).
			Count(&activeSessions).Error; err != nil {
			return err
		}
		if activeSessions > 0 {
			return errors.New("停车场仍有在场车辆，不能删除")
		}
		return tx.Delete(&lot).Error
	})
}