package packagesilence

import (
	"context"
	"strings"
	"time"

	"github.com/google/uuid"
	"gorm.io/gorm"

	approvalapp "github.com/break/junhong_cmp_fiber/internal/application/approval"
	packagedomain "github.com/break/junhong_cmp_fiber/internal/domain/package"
	"github.com/break/junhong_cmp_fiber/internal/infrastructure/audit"
	"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"
)

// PermissionChecker 校验后台账号权限点（由权限服务实现）。
type PermissionChecker interface {
	CheckPermission(ctx context.Context, userID uint, permCode string, platform string) (bool, error)
}

// Setter 在订单支付成功、创建套餐记录的同一事务内设置沉默期（技术方案 §4），并处理后台购买时调整。
type Setter struct {
	db       *gorm.DB
	audit    *audit.Writer
	approval approvalapp.Port
	perms    PermissionChecker
	now      func() time.Time
}

// NewSetter 创建沉默期设置用例。
func NewSetter(db *gorm.DB, writer *audit.Writer) *Setter {
	return &Setter{db: db, audit: writer, now: time.Now}
}

// SetApprovalPort 注入审批创建接缝（购买时调整超默认值需审批时使用）。
func (s *Setter) SetApprovalPort(port approvalapp.Port) {
	s.approval = port
}

// SetPermissionChecker 注入权限校验。
func (s *Setter) SetPermissionChecker(checker PermissionChecker) {
	s.perms = checker
}

// PurchaseOverride 是后台购买时由有权限运营设置的本次沉默期。
// 无人参与的路径（自动购包、钱包自动续费等）不会携带，只用默认值。
type PurchaseOverride struct {
	Days       int
	Reason     string
	OperatorID uint
	submitter  approvalSubmitter
	// needApproval 表示本次订单中至少一笔套餐的设置值超过默认值且未免审批，preparation 已在事务前完成。
	needApproval bool
	preparation  approvalapp.Preparation
	exempt       map[uint]bool // 套餐 ID → 政策是否勾选 purchase_adjust 免审批
	defaults     map[uint]int  // 套餐 ID → 默认沉默期
}

type overrideContextKey struct{}

// WithPurchaseOverride 把购买时调整值放入上下文，由支付成功发放套餐时读取。
func WithPurchaseOverride(ctx context.Context, override *PurchaseOverride) context.Context {
	if override == nil {
		return ctx
	}
	return context.WithValue(ctx, overrideContextKey{}, override)
}

func overrideFromContext(ctx context.Context) *PurchaseOverride {
	value, _ := ctx.Value(overrideContextKey{}).(*PurchaseOverride)
	return value
}

// PrepareOverride 在下单事务前校验购买时调整：权限、天数、原因，并在需要审批时提前完成审批渠道检查。
// days 为空表示不调整。
func (s *Setter) PrepareOverride(ctx context.Context, operatorID uint, days *int, reason string, packages []*model.Package) (*PurchaseOverride, error) {
	if days == nil {
		return nil, nil
	}
	if s.perms == nil {
		return nil, errors.New(errors.CodeSilenceOverrideForbidden)
	}
	allowed, err := s.perms.CheckPermission(ctx, operatorID, constants.PermissionPackageSilenceOverride, constants.PlatformWeb)
	if err != nil {
		return nil, err
	}
	if !allowed {
		return nil, errors.New(errors.CodeSilenceOverrideForbidden)
	}
	if *days < constants.SilencePackageDaysMin || *days > constants.SilencePurchaseAdjustDaysMax {
		return nil, errors.New(errors.CodeSilencePeriodOutOfRange, "本次沉默期至少 1 天")
	}
	reason = strings.TrimSpace(reason)
	if reason == "" {
		return nil, errors.New(errors.CodeInvalidParam, "调整沉默期必须填写原因")
	}
	override := &PurchaseOverride{
		Days: *days, Reason: truncate(reason, 500), OperatorID: operatorID,
		exempt: map[uint]bool{}, defaults: map[uint]int{},
	}
	now := s.now()
	for _, pkg := range packages {
		if pkg == nil || pkg.SilencePeriodDays == nil || pkg.PackageType == constants.PackageTypeAddon {
			continue
		}
		override.defaults[pkg.ID] = *pkg.SilencePeriodDays
		if *days <= *pkg.SilencePeriodDays {
			continue
		}
		match, err := matchPolicy(ctx, s.db, pkg.ID, pkg.SeriesID, now)
		if err != nil {
			return nil, err
		}
		if packagedomain.IsSilenceApprovalExempt(match.ExemptTypes(), constants.SilenceExtensionTypePurchaseAdjust) {
			override.exempt[pkg.ID] = true
			continue
		}
		override.needApproval = true
	}
	if override.needApproval {
		submitter, err := loadSubmitter(ctx, s.db, operatorID)
		if err != nil {
			return nil, err
		}
		preparation, err := prepareApproval(ctx, s.approval, operatorID, "silence-adjust-"+uuid.NewString())
		if err != nil {
			return nil, err
		}
		override.submitter = submitter
		override.preparation = preparation
	}
	return override, nil
}

// Eligible 判断新建套餐记录是否进入沉默期（技术方案 §1）。
func Eligible(usage *model.PackageUsage, pkg *model.Package) bool {
	return usage != nil && pkg != nil && usage.MasterUsageID == nil && usage.PendingRealnameActivation &&
		usage.Status == constants.PackageUsageStatusPending &&
		usage.ExpiryBaseSnapshot == constants.PackageExpiryBaseFromActivation && pkg.SilencePeriodDays != nil
}

// ApplyOnUsageCreatedInTx 为刚创建的套餐记录设置沉默期并写流水（总开关关闭也写，只记录）。
// paidAt 为订单支付成功时间；trigger 为订单支付 / 自动购包等来源。
func (s *Setter) ApplyOnUsageCreatedInTx(ctx context.Context, tx *gorm.DB, usage *model.PackageUsage, pkg *model.Package, paidAt time.Time, trigger string) error {
	if s == nil || !Eligible(usage, pkg) {
		return nil
	}
	defaultDays := *pkg.SilencePeriodDays
	days := defaultDays
	adjusted := false
	needApproval := false
	reason := ""
	override := overrideFromContext(ctx)
	if override != nil {
		reason = override.Reason
		switch {
		case override.Days <= defaultDays || override.exempt[pkg.ID]:
			days = override.Days
			adjusted = override.Days != defaultDays
		case override.needApproval:
			needApproval = true
		}
	}
	deadline := packagedomain.SilenceDeadline(paidAt, days)
	start := paidAt
	values := map[string]any{
		"silence_status": constants.SilenceStatusWaiting, "silence_start_at": start,
		"silence_period_days": days, "silence_deadline_at": deadline, "silence_adjust_pending": needApproval,
	}
	if err := tx.WithContext(ctx).Model(&model.PackageUsage{}).Where("id = ? AND silence_status IS NULL", usage.ID).
		Updates(values).Error; err != nil {
		return errors.Wrap(errors.CodeDatabaseError, err, "设置套餐沉默期失败")
	}
	usage.SilenceStatus = stringPtr(constants.SilenceStatusWaiting)
	usage.SilenceStartAt = &start
	usage.SilencePeriodDays = &days
	usage.SilenceDeadlineAt = &deadline
	usage.SilenceAdjustPending = needApproval
	if err := writeRecord(ctx, tx, s.audit, recordInput{
		Usage: usage, EventType: constants.SilenceRecordEventSet, Trigger: trigger,
		DefaultDays: &defaultDays, IsAdjusted: adjusted, ChangeDays: days - defaultDays, Reason: reason,
		Extra:       map[string]any{"requested_days": overrideDays(override), "adjust_pending": needApproval},
		AuditAction: constants.AuditActionUsageSilenceSet, AuditSummary: "设置套餐沉默期",
	}); err != nil {
		return err
	}
	if needApproval {
		return s.submitAdjustInTx(ctx, tx, usage, pkg, override, defaultDays)
	}
	return nil
}

func overrideDays(override *PurchaseOverride) any {
	if override == nil {
		return nil
	}
	return override.Days
}

// submitAdjustInTx 为超默认值的调整创建批次（path = adjust）与企微审批，审批期间套餐不过期。
func (s *Setter) submitAdjustInTx(ctx context.Context, tx *gorm.DB, usage *model.PackageUsage, pkg *model.Package, override *PurchaseOverride, defaultDays int) error {
	now := s.now()
	requested := override.Days
	batch := &model.PackageSilenceExtensionBatch{
		BatchNo: generateNo(constants.SilenceExtensionBatchNoPrefix, now), Path: constants.SilencePathAdjust,
		ExtensionType: constants.SilenceExtensionTypePurchaseAdjust, ApprovalRequired: true,
		Reason: override.Reason, AdjustPackageUsageID: &usage.ID, AdjustDefaultDays: &defaultDays,
		AdjustRequestedDays: &requested, RequestedBy: override.OperatorID, RequestedByType: constants.SilenceOperatorAccount,
		RequestedAt: now, Status: constants.SilenceBatchStatusPendingApproval, RequestedCount: 1,
	}
	if err := postgres.NewPackageSilenceBatchStore(tx).Create(ctx, batch); err != nil {
		return errors.Wrap(errors.CodeDatabaseError, err, "创建沉默期调整申请失败")
	}
	identifier, err := assetIdentifier(ctx, tx, usage)
	if err != nil {
		return err
	}
	instanceID, err := createApprovalInTx(ctx, tx, s.approval, override.preparation, batch, override.submitter, ApplyTypePurchaseAdjust, map[string]any{
		ApprovalFieldAssetIdentifier: identifier, ApprovalFieldPackageName: pkg.PackageName,
		ApprovalFieldOrderNo: usage.OrderNo, ApprovalFieldDefaultDays: defaultDays,
		ApprovalFieldRequestedDays: requested, ApprovalFieldReason: override.Reason,
		ApprovalFieldOriginalDeadline: formatDate(usage.SilenceDeadlineAt),
	})
	if err != nil {
		return err
	}
	return writeRecord(ctx, tx, s.audit, recordInput{
		Usage: usage, EventType: constants.SilenceRecordEventAdjust, Trigger: constants.SilenceTriggerOrderPaid,
		BeforeStatus: usage.SilenceStatus, BeforeDeadline: usage.SilenceDeadlineAt, DefaultDays: &defaultDays,
		ChangeDays: requested - defaultDays, Reason: override.Reason, ApprovalID: &instanceID, BatchID: &batch.ID,
		Extra:       map[string]any{"requested_days": requested, "stage": "requested"},
		AuditAction: constants.AuditActionUsageSilenceAdjustRequested, AuditSummary: "申请购买时调整沉默期",
	})
}

// assetIdentifier 返回套餐记录当前载体的标识（卡 ICCID / 设备虚拟号或 IMEI）。
func assetIdentifier(ctx context.Context, db *gorm.DB, usage *model.PackageUsage) (string, error) {
	if usage.DeviceID > 0 {
		var device model.Device
		if err := db.WithContext(ctx).Unscoped().Select("id", "virtual_no", "imei").Where("id = ?", usage.DeviceID).First(&device).Error; err != nil {
			return "", errors.Wrap(errors.CodeDatabaseError, err, "查询设备标识失败")
		}
		if device.VirtualNo != "" {
			return device.VirtualNo, nil
		}
		return device.IMEI, nil
	}
	var card model.IotCard
	if err := db.WithContext(ctx).Unscoped().Select("id", "iccid").Where("id = ?", usage.IotCardID).First(&card).Error; err != nil {
		return "", errors.Wrap(errors.CodeDatabaseError, err, "查询卡标识失败")
	}
	return card.ICCID, nil
}