package assetautorenewal

import (
	"context"
	"time"

	"go.uber.org/zap"
	"gorm.io/gorm"

	"github.com/break/junhong_cmp_fiber/internal/model"
	assetquery "github.com/break/junhong_cmp_fiber/internal/query/assetautorenewal"
	"github.com/break/junhong_cmp_fiber/pkg/constants"
	"github.com/break/junhong_cmp_fiber/pkg/errors"
)

// ScanResult 汇总一次每日扫描的可观察结果。
type ScanResult struct {
	Converged  int64
	Candidates int
	Attempted  int
	Succeeded  int
	Failed     int
	Skipped    int
	Duplicated int
}

// RunDailyScan 执行一次每日自动续费扫描：先收敛历史非终态尝试，再按资产扫描候选并逐项执行。
//
// 只有扫描级失败（配置读取、候选读取、数据库不可用）返回错误交既有任务重试；单个资产执行失败
// 在用例内捕获并落终态后继续处理其余资产。总开关关闭时不创建任何新尝试与订单，既有记录保留。
func (s *Service) RunDailyScan(ctx context.Context) (ScanResult, error) {
	result := ScanResult{}
	if s.db == nil {
		return result, errors.New(errors.CodeServiceUnavailable, "自动续费用例未配置")
	}
	converged, err := s.attemptStore.ConvergeUnfinished(ctx, s.today())
	if err != nil {
		return result, err
	}
	result.Converged = converged
	if converged > 0 {
		s.logger.Info("自动续费历史非终态尝试已收敛", zap.Int64("converged", converged))
	}
	config, err := s.configStore.Get(ctx)
	if err != nil {
		if err == gorm.ErrRecordNotFound {
			return result, errors.New(errors.CodeNotFound, "自动续费配置不存在")
		}
		return result, errors.Wrap(errors.CodeDatabaseError, err, "读取自动续费配置失败")
	}
	if config.Enabled != 1 {
		s.logger.Info("自动续费总开关关闭，本次扫描不创建尝试与订单")
		return result, nil
	}
	if config.Scope != constants.AssetAutoRenewalScopeAll && config.Scope != constants.AssetAutoRenewalScopeSpecified {
		return result, errors.New(errors.CodeInvalidStatus, "自动续费配置范围取值非法")
	}
	candidates, err := s.candidates.Candidates(ctx, config.DaysBeforeExpiry)
	if err != nil {
		return result, err
	}
	result.Candidates = len(candidates)
	scope := newScopeMatcher(config)
	for _, candidate := range candidates {
		if !scope.matches(candidate.CurrentPackageID) {
			continue
		}
		outcome, processErr := s.processCandidate(ctx, candidate, config)
		if processErr != nil {
			// 单资产失败已落终态，继续处理其余资产；扫描任务本身不因该资产失败而失败。
			s.logger.Error("自动续费单资产执行失败，继续处理其余资产",
				zap.String("asset_type", candidate.AssetType), zap.Uint("asset_id", candidate.AssetID),
				zap.Error(processErr))
			result.Failed++
			continue
		}
		switch outcome {
		case candidateSucceeded:
			result.Attempted++
			result.Succeeded++
		case candidateFailed:
			result.Attempted++
			result.Failed++
		case candidateSkipped:
			result.Attempted++
			result.Skipped++
		default:
			result.Duplicated++
		}
	}
	s.logger.Info("自动续费每日扫描完成",
		zap.Int64("converged", result.Converged), zap.Int("candidates", result.Candidates),
		zap.Int("succeeded", result.Succeeded), zap.Int("failed", result.Failed),
		zap.Int("skipped", result.Skipped), zap.Int("duplicated", result.Duplicated))
	return result, nil
}

// scanOutcome 是一次候选处理的终态归属，用于汇总扫描结果。
type scanOutcome int

const (
	candidateDuplicated scanOutcome = iota
	candidateSucceeded
	candidateFailed
	candidateSkipped
)

// scopeMatcher 表达配置的适用范围：全部主套餐，或指定主套餐集合。
//
// 运行时只按当前主套餐商品是否在集合内判定，不因后来下架而拒绝——下架交给续费豁免判定。
type scopeMatcher struct {
	all        bool
	packageIDs map[uint]struct{}
}

func newScopeMatcher(config *model.AssetAutoRenewalConfig) scopeMatcher {
	if config.Scope == constants.AssetAutoRenewalScopeAll {
		return scopeMatcher{all: true}
	}
	ids := make(map[uint]struct{}, len(config.PackageIDs))
	for _, packageID := range config.PackageIDs {
		ids[packageID] = struct{}{}
	}
	return scopeMatcher{packageIDs: ids}
}

func (m scopeMatcher) matches(packageID uint) bool {
	if m.all {
		return true
	}
	_, exists := m.packageIDs[packageID]
	return exists
}

// processCandidate 处理单个候选：占位写入、执行、落终态与通知。
//
// 占位冲突表示该资产当日已尝试，直接跳过且不重复扣款；执行阶段的失败与跳过各以独立短事务落终态。
func (s *Service) processCandidate(ctx context.Context, candidate assetquery.Candidate, config *model.AssetAutoRenewalConfig) (scanOutcome, error) {
	triggerDate := s.today()
	attempt, err := s.buildAttempt(ctx, candidate, config, triggerDate)
	if err != nil {
		return candidateFailed, err
	}
	created, err := s.attemptStore.CreatePlaceholder(ctx, attempt)
	if err != nil {
		return candidateFailed, err
	}
	if !created {
		s.logger.Info("该资产当日已存在自动续费尝试，跳过",
			zap.String("asset_type", candidate.AssetType), zap.Uint("asset_id", candidate.AssetID))
		return candidateDuplicated, nil
	}
	facts, halt, err := s.executeRenewal(ctx, candidate, attempt, config.DaysBeforeExpiry)
	if halt != nil {
		if halt.SkipReason != "" {
			return candidateSkipped, s.finalizeSkip(ctx, attempt, halt)
		}
		return candidateFailed, s.finalizeFailure(ctx, attempt, halt.FailureReason, halt.Detail)
	}
	if err != nil {
		s.logger.Error("自动续费事务失败并已整体回滚",
			zap.String("asset_type", candidate.AssetType), zap.Uint("asset_id", candidate.AssetID), zap.Error(err))
		return candidateFailed, s.finalizeFailure(ctx, attempt, constants.AssetAutoRenewalFailureOrderFailed,
			"续购事务执行失败并已整体回滚，未产生订单、扣款与套餐事实")
	}
	s.logger.Info("自动续费续购成功",
		zap.String("asset_type", candidate.AssetType), zap.Uint("asset_id", candidate.AssetID),
		zap.Uint("order_id", facts.OrderID), zap.String("order_no", facts.OrderNo),
		zap.Int64("renew_price", facts.RenewPrice))
	return candidateSucceeded, nil
}

// buildAttempt 组装占位尝试记录，冻结触发时的客户、店铺、配置窗口与套餐快照。
func (s *Service) buildAttempt(ctx context.Context, candidate assetquery.Candidate, config *model.AssetAutoRenewalConfig, triggerDate time.Time) (*model.AssetAutoRenewalAttempt, error) {
	sequence, err := s.attemptStore.CountByAsset(ctx, candidate.AssetType, candidate.AssetID, triggerDate)
	if err != nil {
		return nil, err
	}
	finalExpiresAt := candidate.FinalExpiresAt
	attempt := &model.AssetAutoRenewalAttempt{
		AssetType: candidate.AssetType, AssetID: candidate.AssetID, TriggerDate: triggerDate,
		Status:        constants.AssetAutoRenewalAttemptStatusProcessing,
		CustomerID:    candidate.CustomerID,
		ShopID:        candidate.ShopID,
		ConfigVersion: config.ConfigVersion, WindowDays: config.DaysBeforeExpiry,
		FinalExpiresAt:   &finalExpiresAt,
		CurrentUsageID:   candidate.CurrentUsageID,
		CurrentPackageID: candidate.CurrentPackageID,
		RenewPackageID:   candidate.CurrentPackageID,
		OperatorType:     constants.AssetAutoRenewalOperatorTypeSystemTask,
		OperatorID:       constants.TaskTypeAssetAutoRenewalScan,
		AttemptSeq:       int(sequence) + 1,
	}
	return attempt, nil
}

// finalizeSkip 以独立短事务落跳过终态：不扣款、不建订单、不发送通知。
func (s *Service) finalizeSkip(ctx context.Context, attempt *model.AssetAutoRenewalAttempt, halt *renewalHalt) error {
	_, err := s.attemptStore.Finalize(ctx, attempt.ID, map[string]any{
		"status":         constants.AssetAutoRenewalAttemptStatusSkipped,
		"skip_reason":    halt.SkipReason,
		"failure_reason": "",
		"failure_detail": halt.Detail,
	})
	if err != nil {
		return err
	}
	s.logger.Info("自动续费跳过该资产",
		zap.String("asset_type", attempt.AssetType), zap.Uint("asset_id", attempt.AssetID),
		zap.String("skip_reason", halt.SkipReason))
	return nil
}

// finalizeFailure 以独立短事务落失败终态，并在同一事务内投递通知与写失败审计。
//
// 该短事务与已回滚的续费事务不共用连接或事务（ENG-TX-001 例外），条件更新依据尝试记录仍非终态；
// 已被并发收敛时不再投递通知与审计。中断收敛（interrupted）不属于通知口径，不会被通知。
func (s *Service) finalizeFailure(ctx context.Context, attempt *model.AssetAutoRenewalAttempt, reason, detail string) error {
	return s.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
		updated, err := s.attemptStore.FinalizeInTx(ctx, tx, attempt.ID, map[string]any{
			"status":         constants.AssetAutoRenewalAttemptStatusFailed,
			"failure_reason": reason,
			"failure_detail": detail,
			"skip_reason":    "",
		})
		if err != nil {
			return err
		}
		if !updated {
			s.logger.Info("自动续费尝试已被并发收敛，跳过通知与审计",
				zap.Uint("attempt_id", attempt.ID))
			return nil
		}
		if notifyErr := s.appendFailureNotifications(ctx, tx, failureNotification{
			AttemptID: attempt.ID, AssetType: attempt.AssetType, AssetID: attempt.AssetID,
			Identifier: s.assetIdentifier(ctx, attempt.AssetType, attempt.AssetID),
			ShopID:     attempt.ShopID, CustomerID: attempt.CustomerID,
			TriggerDate: attempt.TriggerDate, Reason: reason,
			PackageName: s.packageName(ctx, attempt.RenewPackageID), FinalExpiresAt: attempt.FinalExpiresAt,
		}); notifyErr != nil {
			return notifyErr
		}
		return s.appendFailureAudit(ctx, tx, attempt, reason, detail)
	})
}