package packagepkg

import (
	"context"
	"time"

	"github.com/break/junhong_cmp_fiber/internal/model"
	"github.com/break/junhong_cmp_fiber/internal/store/postgres"
	"github.com/break/junhong_cmp_fiber/pkg/constants"
	"github.com/break/junhong_cmp_fiber/pkg/errors"
	"github.com/redis/go-redis/v9"
	"go.uber.org/zap"
	"gorm.io/gorm"
)

// StopResumeCallback 任务 24.6: 停复机回调接口
// 用于在流量用完时触发停机操作
type StopResumeCallback interface {
	// CheckAndStopCard 检查流量耗尽并停机
	CheckAndStopCard(ctx context.Context, cardID uint) error
}

type UsageService struct {
	db                      *gorm.DB
	redis                   *redis.Client
	packageUsageStore       *postgres.PackageUsageStore
	packageUsageDailyRecord *postgres.PackageUsageDailyRecordStore
	logger                  *zap.Logger
	stopResumeCallback      StopResumeCallback // 停复机回调，可选
}

func NewUsageService(
	db *gorm.DB,
	redis *redis.Client,
	packageUsageStore *postgres.PackageUsageStore,
	packageUsageDailyRecord *postgres.PackageUsageDailyRecordStore,
	logger *zap.Logger,
) *UsageService {
	return &UsageService{
		db:                      db,
		redis:                   redis,
		packageUsageStore:       packageUsageStore,
		packageUsageDailyRecord: packageUsageDailyRecord,
		logger:                  logger,
	}
}

// SetStopResumeCallback 任务 24.6: 设置停复机回调
// 在应用启动时由 bootstrap 调用，注入停复机服务
func (s *UsageService) SetStopResumeCallback(callback StopResumeCallback) {
	s.stopResumeCallback = callback
}

// DeductDataUsage 任务 10.2-10.6: 按优先级扣减流量
// 扣减顺序：加油包（按 priority ASC） → 主套餐
// 流量用完时自动标记 status=2，所有套餐用完时触发停机
func (s *UsageService) DeductDataUsage(ctx context.Context, carrierType string, carrierID uint, usageMB int64) error {
	if usageMB <= 0 {
		return errors.New(errors.CodeInvalidParam, "扣减流量必须大于0")
	}

	return s.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
		// 查询所有生效中的套餐（按优先级排序）
		var packages []*model.PackageUsage
		query := tx.Where("status = ?", constants.PackageUsageStatusActive)

		if carrierType == "iot_card" {
			query = query.Where("iot_card_id = ?", carrierID)
		} else if carrierType == "device" {
			query = query.Where("device_id = ?", carrierID)
		} else {
			return errors.New(errors.CodeInvalidParam, "无效的载体类型")
		}

		// 加油包按 priority ASC 排序，主套餐在后
		if err := query.Order("CASE WHEN master_usage_id IS NOT NULL THEN 0 ELSE 1 END, priority ASC").
			Find(&packages).Error; err != nil {
			return errors.Wrap(errors.CodeDatabaseError, err, "查询生效套餐失败")
		}

		if len(packages) == 0 {
			return errors.New(errors.CodeNoAvailablePackage, "没有可用套餐")
		}

		// 按优先级扣减流量
		remainingUsage := usageMB
		today := time.Now().Format("2006-01-02")

		for _, pkg := range packages {
			if remainingUsage <= 0 {
				break
			}

			// 计算当前套餐剩余额度
			remainingQuota := pkg.DataLimitMB - pkg.DataUsageMB
			if remainingQuota <= 0 {
				// 套餐已用完，标记为已用完
				if err := tx.Model(pkg).Update("status", constants.PackageUsageStatusDepleted).Error; err != nil {
					return errors.Wrap(errors.CodeDatabaseError, err, "更新套餐状态失败")
				}
				continue
			}

			// 本次从该套餐扣减的流量
			var deductFromPkg int64
			if remainingUsage <= remainingQuota {
				deductFromPkg = remainingUsage
			} else {
				deductFromPkg = remainingQuota
			}

			// 更新套餐使用量
			newUsage := pkg.DataUsageMB + deductFromPkg
			updates := map[string]interface{}{
				"data_usage_mb": newUsage,
			}

			// 检查是否用完
			if newUsage >= pkg.DataLimitMB {
				updates["status"] = constants.PackageUsageStatusDepleted
			}

			if err := tx.Model(pkg).Updates(updates).Error; err != nil {
				return errors.Wrap(errors.CodeDatabaseError, err, "更新套餐使用量失败")
			}

			// 任务 10.6: 写入日记录
			if err := s.updateDailyRecord(ctx, tx, pkg.ID, today, deductFromPkg, newUsage); err != nil {
				return err
			}

			remainingUsage -= deductFromPkg

			s.logger.Info("扣减套餐流量",
				zap.Uint("usage_id", pkg.ID),
				zap.Int64("deduct_mb", deductFromPkg),
				zap.Int64("new_usage_mb", newUsage),
				zap.Int64("data_limit_mb", pkg.DataLimitMB))
		}

		// 如果流量扣减未完成，说明所有套餐都不够
		if remainingUsage > 0 {
			s.logger.Warn("流量不足",
				zap.String("carrier_type", carrierType),
				zap.Uint("carrier_id", carrierID),
				zap.Int64("requested_mb", usageMB),
				zap.Int64("remaining_mb", remainingUsage))
			return errors.New(errors.CodeInsufficientQuota, "流量不足")
		}

		// 任务 10.5: 检查是否所有套餐都用完（触发停机）
		if err := s.checkAndTriggerSuspension(ctx, tx, carrierType, carrierID); err != nil {
			return err
		}

		return nil
	})
}

// updateDailyRecord 任务 10.6: 更新日流量记录
func (s *UsageService) updateDailyRecord(ctx context.Context, tx *gorm.DB, packageUsageID uint, dateStr string, dailyUsageMB, cumulativeUsageMB int64) error {
	// 解析日期字符串
	date, err := time.Parse("2006-01-02", dateStr)
	if err != nil {
		return errors.Wrap(errors.CodeInvalidParam, err, "日期格式错误")
	}

	// 查询是否已有今日记录
	var record model.PackageUsageDailyRecord
	err = tx.Where("package_usage_id = ? AND date = ?", packageUsageID, date).
		First(&record).Error

	if err == gorm.ErrRecordNotFound {
		// 创建新记录
		record = model.PackageUsageDailyRecord{
			PackageUsageID:    packageUsageID,
			Date:              date,
			DailyUsageMB:      int(dailyUsageMB),
			CumulativeUsageMB: cumulativeUsageMB,
		}
		if err := tx.Create(&record).Error; err != nil {
			return errors.Wrap(errors.CodeDatabaseError, err, "创建日流量记录失败")
		}
	} else if err != nil {
		return errors.Wrap(errors.CodeDatabaseError, err, "查询日流量记录失败")
	} else {
		// 更新现有记录
		updates := map[string]interface{}{
			"daily_usage_mb":      record.DailyUsageMB + int(dailyUsageMB),
			"cumulative_usage_mb": cumulativeUsageMB,
		}
		if err := tx.Model(&record).Updates(updates).Error; err != nil {
			return errors.Wrap(errors.CodeDatabaseError, err, "更新日流量记录失败")
		}
	}

	return nil
}

// checkAndTriggerSuspension 任务 10.5: 检查停机条件
func (s *UsageService) checkAndTriggerSuspension(ctx context.Context, tx *gorm.DB, carrierType string, carrierID uint) error {
	// 查询是否还有生效中的套餐
	var activeCount int64
	query := tx.Model(&model.PackageUsage{}).
		Where("status = ?", constants.PackageUsageStatusActive)

	if carrierType == "iot_card" {
		query = query.Where("iot_card_id = ?", carrierID)
	} else if carrierType == "device" {
		query = query.Where("device_id = ?", carrierID)
	}

	if err := query.Count(&activeCount).Error; err != nil {
		return errors.Wrap(errors.CodeDatabaseError, err, "查询生效套餐数量失败")
	}

	// 如果没有生效中的套餐，触发停机操作
	if activeCount == 0 {
		s.logger.Warn("所有套餐已用完，触发停机",
			zap.String("carrier_type", carrierType),
			zap.Uint("carrier_id", carrierID))

		// 任务 24.6: 调用停复机服务执行停机
		if s.stopResumeCallback != nil && carrierType == "iot_card" {
			// 在事务外异步执行停机，避免长事务
			go func() {
				stopCtx := context.Background()
				if err := s.stopResumeCallback.CheckAndStopCard(stopCtx, carrierID); err != nil {
					s.logger.Error("调用停机服务失败",
						zap.Uint("card_id", carrierID),
						zap.Error(err))
				}
			}()
		}
	}

	return nil
}