package postgres

import (
	"context"
	"time"

	"gorm.io/gorm"
	"gorm.io/gorm/clause"

	"github.com/break/junhong_cmp_fiber/internal/model"
	"github.com/break/junhong_cmp_fiber/pkg/constants"
)

// effectivePackageStatuses 是"采集时刻有效套餐"认可的套餐状态：状态可能在采集之后才变为已用完或已过期，
// 是否在采集时刻有效由激活时间与到期时间判断。
var effectivePackageStatuses = []int{
	constants.PackageUsageStatusActive, constants.PackageUsageStatusDepleted, constants.PackageUsageStatusExpired,
}

// EffectivePackages 是一次"采集时刻有效套餐"查询的结果。
type EffectivePackages struct {
	// CarrierType 与 CarrierID 是实际扣减载体：卡自身没有有效套餐时回退到卡当前绑定的设备。
	CarrierType string
	CarrierID   uint
	// Packages 按扣减优先级排序：加油包优先，再按 priority、id。
	Packages []*model.PackageUsage
}

// FindEffectivePackagesAt 按"有套餐"共用口径查询卡在采集时刻的有效套餐：状态为生效中、已用完或已过期，
// 激活时间不晚于采集时间（为空按已生效），到期时间为空或晚于采集时间，未退款；
// 卡自身一个都没有时看卡当前绑定设备的套餐。lock 为 true 时对查到的套餐行加 FOR UPDATE。
// 采集侧（写入范围、是否发事件、采集记录、日用量 0 行）与扣费侧共用本函数，避免两边口径不一致。
func FindEffectivePackagesAt(ctx context.Context, db *gorm.DB, cardID uint, observedAt time.Time, lock bool) (EffectivePackages, error) {
	own, err := queryEffectivePackages(ctx, db, "iot_card_id = ?", cardID, observedAt, lock)
	if err != nil || len(own) > 0 {
		return EffectivePackages{CarrierType: constants.AssetTypeIotCard, CarrierID: cardID, Packages: own}, err
	}
	var deviceIDs []uint
	if err := db.WithContext(ctx).Model(&model.DeviceSimBinding{}).
		Where("iot_card_id = ? AND bind_status = ?", cardID, constants.BindStatusBound).
		Limit(1).Pluck("device_id", &deviceIDs).Error; err != nil {
		return EffectivePackages{}, err
	}
	if len(deviceIDs) == 0 {
		return EffectivePackages{CarrierType: constants.AssetTypeIotCard, CarrierID: cardID}, nil
	}
	devicePackages, err := queryEffectivePackages(ctx, db, "device_id = ?", deviceIDs[0], observedAt, lock)
	if err != nil {
		return EffectivePackages{}, err
	}
	if len(devicePackages) == 0 {
		return EffectivePackages{CarrierType: constants.AssetTypeIotCard, CarrierID: cardID}, nil
	}
	return EffectivePackages{CarrierType: constants.AssetTypeDevice, CarrierID: deviceIDs[0], Packages: devicePackages}, nil
}

func queryEffectivePackages(ctx context.Context, db *gorm.DB, carrierCondition string, carrierID uint, observedAt time.Time, lock bool) ([]*model.PackageUsage, error) {
	query := db.WithContext(ctx).Model(&model.PackageUsage{}).
		Where(carrierCondition, carrierID).
		Where("status IN ?", effectivePackageStatuses).
		Where("activated_at IS NULL OR activated_at <= ?", observedAt).
		Where("expires_at IS NULL OR expires_at > ?", observedAt).
		Where("refund_id IS NULL")
	if lock {
		query = query.Clauses(clause.Locking{Strength: "UPDATE"})
	}
	var packages []*model.PackageUsage
	err := query.Order("CASE WHEN master_usage_id IS NOT NULL THEN 0 ELSE 1 END, priority ASC, id ASC").Find(&packages).Error
	return packages, err
}

// EnsureDailyUsageRows 为每个套餐确保 date 当天一行套餐日用量（没有则写 0，已有不动）。
func EnsureDailyUsageRows(ctx context.Context, db *gorm.DB, packageUsageIDs []uint, date time.Time, cumulative map[uint]int64) error {
	for _, id := range packageUsageIDs {
		if err := db.WithContext(ctx).Exec(`
INSERT INTO tb_package_usage_daily_record (package_usage_id, date, daily_usage_mb, cumulative_usage_mb, created_at, updated_at)
VALUES (?, ?::date, 0, ?, NOW(), NOW())
ON CONFLICT (package_usage_id, date) DO NOTHING`, id, date.Format(cardFlowDateLayout), cumulative[id]).Error; err != nil {
			return err
		}
	}
	return nil
}

// AddDailyUsage 原子累加套餐 date 当天用量并覆盖累计用量；当天没有行时新建。
func AddDailyUsage(ctx context.Context, db *gorm.DB, packageUsageID uint, date time.Time, dailyMB int64, cumulativeMB int64) error {
	return db.WithContext(ctx).Exec(`
INSERT INTO tb_package_usage_daily_record (package_usage_id, date, daily_usage_mb, cumulative_usage_mb, created_at, updated_at)
VALUES (?, ?::date, ?, ?, NOW(), NOW())
ON CONFLICT (package_usage_id, date) DO UPDATE SET
    daily_usage_mb      = tb_package_usage_daily_record.daily_usage_mb + EXCLUDED.daily_usage_mb,
    cumulative_usage_mb = EXCLUDED.cumulative_usage_mb,
    updated_at          = NOW()`, packageUsageID, date.Format(cardFlowDateLayout), dailyMB, cumulativeMB).Error
}