// Package integrationlog 提供外部交互尝试的可靠持久化能力。
package integrationlog

import (
	"context"
	"crypto/sha256"
	"encoding/hex"
	"strings"
	"time"
	"unicode/utf8"

	"github.com/google/uuid"
	"go.uber.org/zap"
	"gorm.io/datatypes"
	"gorm.io/gorm"
	"gorm.io/gorm/clause"

	"github.com/break/junhong_cmp_fiber/internal/infrastructure/audit"
	"github.com/break/junhong_cmp_fiber/internal/model"
	"github.com/break/junhong_cmp_fiber/pkg/auditcontext"
	"github.com/break/junhong_cmp_fiber/pkg/constants"
	pkgerrors "github.com/break/junhong_cmp_fiber/pkg/errors"
	"github.com/break/junhong_cmp_fiber/pkg/sanitizer"
)

// Attempt 描述一次外部调用前必须持久化的稳定事实。
type Attempt struct {
	IntegrationID    string
	Provider         string
	Direction        string
	Operation        string
	ExternalID       *string
	ResourceType     string
	ResourceID       *string
	ResourceKey      *string
	TriggerSource    *string
	TriggerScene     *string
	TriggerSeries    *string
	ScheduledAt      *time.Time
	StartedAt        *time.Time
	Attempt          int
	RequestSummary   any
	Metadata         any
	RequestID        *string
	CorrelationID    *string
	AuditEventID     *uint
	InitialResult    string
	RecoveryStrategy *string
}

// Completion 描述外部尝试从待处理状态进入终态的结果。
type Completion struct {
	Result              string
	HTTPStatus          int
	ProviderCode        string
	ProviderMessage     string
	SafeProviderMessage string
	ResponseSummary     any
	DurationMS          int64
	StateChanged        bool
	ResourceID          *string
	ResourceKey         *string
	RecoveryStrategy    string
}

// InboundAttempt 描述业务处理前必须保存的入站回调安全事实。
type InboundAttempt struct {
	IntegrationID  string
	IdempotencyKey string
	Provider       string
	Operation      string
	ExternalID     string
	ResourceType   string
	ResourceID     *string
	ResourceKey    *string
	RawPayload     []byte
	ContentType    string
	RequestID      *string
	CorrelationID  *string
	AuditEventID   *uint
}

// Repository 负责创建稳定尝试及受控地进入终态。
type Repository struct {
	db    *gorm.DB
	now   func() time.Time
	audit *audit.Writer
}

// NewRepository 创建 Integration Log Repository。
func NewRepository(db *gorm.DB) *Repository {
	return &Repository{db: db, now: time.Now, audit: audit.NewWriter(audit.NewRegistry(), nil)}
}

// Start 在实际调用外部系统前持久化尝试事实。
func (r *Repository) Start(ctx context.Context, input Attempt) (*model.IntegrationLog, error) {
	if r == nil || r.db == nil {
		return nil, pkgerrors.New(pkgerrors.CodeInvalidStatus, "Integration Log 数据库未配置")
	}
	if err := validateAttempt(input); err != nil {
		return nil, err
	}
	requestSummary, err := marshalSummary(input.RequestSummary)
	if err != nil {
		return nil, pkgerrors.Wrap(pkgerrors.CodeInvalidParam, err, "Integration Log 请求摘要无效")
	}
	metadata, err := marshalSummary(input.Metadata)
	if err != nil {
		return nil, pkgerrors.Wrap(pkgerrors.CodeInvalidParam, err, "Integration Log 元数据无效")
	}
	if input.IntegrationID == "" {
		input.IntegrationID = uuid.NewString()
	}
	if input.AuditEventID == nil && input.TriggerSeries != nil {
		input.AuditEventID = r.auditEventIDForSeries(ctx, *input.TriggerSeries)
	}
	if input.AuditEventID == nil {
		input.AuditEventID = r.recordAuditEvent(ctx, constants.AuditActionIntegrationAttemptStarted, input.IntegrationID, input.Provider, input.Direction, input.Operation, input.ResourceType, input.ResourceID, input.ResourceKey, input.CorrelationID)
	}
	autoAttempt := input.Attempt <= 0 && input.TriggerSeries != nil
	if input.Attempt <= 0 {
		input.Attempt = 1
	}
	if input.StartedAt == nil {
		startedAt := r.now().UTC()
		input.StartedAt = &startedAt
	}
	result := input.InitialResult
	if result == "" {
		result = constants.IntegrationResultPending
	}
	resourceType := optionalString(input.ResourceType)
	log := &model.IntegrationLog{
		IntegrationID: input.IntegrationID, Provider: input.Provider, Direction: input.Direction,
		Operation: input.Operation, ExternalID: sanitizedOptionalText(input.ExternalID), ResourceType: resourceType,
		ResourceID: input.ResourceID, ResourceKey: sanitizedOptionalText(input.ResourceKey), TriggerSource: input.TriggerSource,
		TriggerScene: sanitizedOptionalText(input.TriggerScene), TriggerSeries: input.TriggerSeries, ScheduledAt: input.ScheduledAt,
		StartedAt: input.StartedAt, Attempt: input.Attempt, Result: result,
		RequestSummary: requestSummary, Metadata: metadata, RequestID: input.RequestID,
		CorrelationID: input.CorrelationID, AuditEventID: input.AuditEventID,
		RecoveryStrategy: sanitizedOptionalText(input.RecoveryStrategy),
	}
	createAttempt := func(tx *gorm.DB) error {
		if !autoAttempt {
			return tx.Create(log).Error
		}
		if err := tx.Exec("SELECT pg_advisory_xact_lock(hashtext(?))", *input.TriggerSeries).Error; err != nil {
			return err
		}
		if err := tx.Model(&model.IntegrationLog{}).Select("COALESCE(MAX(attempt), 0) + 1").
			Where("trigger_series = ?", *input.TriggerSeries).Scan(&log.Attempt).Error; err != nil {
			return err
		}
		return tx.Create(log).Error
	}
	var createErr error
	if autoAttempt {
		createErr = r.db.WithContext(ctx).Transaction(createAttempt)
	} else {
		createErr = createAttempt(r.db.WithContext(ctx))
	}
	if createErr != nil {
		return nil, pkgerrors.Wrap(pkgerrors.CodeDatabaseError, createErr, "写入 Integration Log 失败")
	}
	return log, nil
}

// Complete 仅允许把待处理尝试条件更新为一个公开终态。
func (r *Repository) Complete(ctx context.Context, integrationID string, completion Completion) (*model.IntegrationLog, error) {
	if r == nil || r.db == nil {
		return nil, pkgerrors.New(pkgerrors.CodeInvalidStatus, "Integration Log 数据库未配置")
	}
	if !validRequiredString(integrationID, constants.IntegrationIDMaxLength) ||
		!validOptionalString(completion.ResourceID, constants.IntegrationResourceIDMaxLength) ||
		!validOptionalString(completion.ResourceKey, constants.IntegrationResourceKeyMaxLength) ||
		!isTerminalResult(completion.Result) {
		return nil, pkgerrors.New(pkgerrors.CodeInvalidParam, "Integration Log 终态参数无效")
	}
	if completion.Result == constants.IntegrationResultUnknown && strings.TrimSpace(completion.RecoveryStrategy) == "" {
		return nil, pkgerrors.New(pkgerrors.CodeInvalidParam, "结果未知必须记录明确恢复策略")
	}
	safeProviderMessage := sanitizer.SanitizeText(strings.TrimSpace(completion.SafeProviderMessage))
	if safeProviderMessage != "" && utf8.RuneCountInString(constants.IntegrationSafeMessagePrefix+safeProviderMessage) > constants.IntegrationProviderMessageMaxLength {
		return nil, pkgerrors.New(pkgerrors.CodeInvalidParam, "Integration Log 安全结果摘要过长")
	}
	responseSummary, err := marshalSummary(completion.ResponseSummary)
	if err != nil {
		return nil, pkgerrors.Wrap(pkgerrors.CodeInvalidParam, err, "Integration Log 响应摘要无效")
	}
	updates := map[string]any{
		"result": completion.Result, "duration_ms": completion.DurationMS,
		"state_changed": completion.StateChanged, "response_summary": responseSummary,
		"updated_at": r.now().UTC(),
	}
	if completion.HTTPStatus != 0 {
		updates["http_status"] = completion.HTTPStatus
	}
	if completion.ProviderCode != "" {
		updates["provider_code"] = completion.ProviderCode
	}
	if safeProviderMessage != "" {
		updates["provider_message"] = constants.IntegrationSafeMessagePrefix + safeProviderMessage
	} else if completion.ProviderMessage != "" {
		updates["provider_message"] = sanitizer.TextSummary(completion.ProviderMessage)
	}
	if completion.ResourceID != nil {
		updates["resource_id"] = completion.ResourceID
	}
	if completion.ResourceKey != nil {
		updates["resource_key"] = sanitizedOptionalText(completion.ResourceKey)
	}
	if completion.RecoveryStrategy != "" {
		updates["recovery_strategy"] = sanitizer.SanitizeText(completion.RecoveryStrategy)
	}
	result := r.db.WithContext(ctx).Model(&model.IntegrationLog{}).
		Where("integration_id = ? AND result = ?", integrationID, constants.IntegrationResultPending).
		Updates(updates)
	if result.Error != nil {
		return nil, pkgerrors.Wrap(pkgerrors.CodeDatabaseError, result.Error, "终结 Integration Log 失败")
	}
	if result.RowsAffected != 1 {
		return nil, pkgerrors.New(pkgerrors.CodeConflict, "Integration Log 已进入终态或不存在")
	}
	var saved model.IntegrationLog
	if err := r.db.WithContext(ctx).Where("integration_id = ?", integrationID).First(&saved).Error; err != nil {
		return nil, pkgerrors.Wrap(pkgerrors.CodeDatabaseError, err, "读取 Integration Log 终态失败")
	}
	return &saved, nil
}

// RecordInbound 在业务处理前幂等保存入站回调的安全摘要。
func (r *Repository) RecordInbound(ctx context.Context, input InboundAttempt) (*model.IntegrationLog, bool, error) {
	if r == nil || r.db == nil {
		return nil, false, pkgerrors.New(pkgerrors.CodeInvalidStatus, "Integration Log 数据库未配置")
	}
	if input.Provider == "" || input.Operation == "" || input.IdempotencyKey == "" ||
		!validGeneratedString(input.IntegrationID, constants.IntegrationIDMaxLength) ||
		!validOptionalString(input.ResourceID, constants.IntegrationResourceIDMaxLength) ||
		!validOptionalString(input.ResourceKey, constants.IntegrationResourceKeyMaxLength) ||
		!validOptionalString(input.CorrelationID, constants.IntegrationCorrelationIDMaxLength) {
		return nil, false, pkgerrors.New(pkgerrors.CodeInvalidParam, "入站 Integration Log 参数无效")
	}
	if input.IntegrationID == "" {
		input.IntegrationID = uuid.NewString()
	}
	if input.AuditEventID == nil {
		input.AuditEventID = r.recordAuditEvent(ctx, constants.AuditActionIntegrationInboundReceived, input.IntegrationID, input.Provider, constants.IntegrationDirectionInbound, input.Operation, input.ResourceType, input.ResourceID, input.ResourceKey, input.CorrelationID)
	}
	triggerSeries := input.IntegrationID
	hash := sha256.Sum256(input.RawPayload)
	summary, err := marshalSummary(map[string]any{
		"content_type":  input.ContentType,
		"payload_bytes": len(input.RawPayload),
		"content_hash":  hex.EncodeToString(hash[:]),
	})
	if err != nil {
		return nil, false, pkgerrors.Wrap(pkgerrors.CodeInvalidParam, err, "入站 Integration Log 摘要无效")
	}
	now := r.now().UTC()
	log := &model.IntegrationLog{
		IntegrationID: input.IntegrationID, IdempotencyKey: &input.IdempotencyKey,
		Provider: input.Provider, Direction: constants.IntegrationDirectionInbound, Operation: input.Operation,
		ExternalID: sanitizedOptionalText(optionalString(input.ExternalID)), ResourceType: optionalString(input.ResourceType),
		ResourceID: input.ResourceID, ResourceKey: sanitizedOptionalText(input.ResourceKey), StartedAt: &now, Attempt: 1,
		TriggerSeries: &triggerSeries,
		Result:        constants.IntegrationResultPending, RequestSummary: summary,
		ContentHash: hex.EncodeToString(hash[:]), RequestID: input.RequestID, CorrelationID: input.CorrelationID,
		AuditEventID: input.AuditEventID,
	}
	result := r.db.WithContext(ctx).Clauses(clause.OnConflict{
		Columns:   []clause.Column{{Name: "provider"}, {Name: "operation"}, {Name: "idempotency_key"}},
		DoNothing: true,
	}).Create(log)
	if result.Error != nil {
		return nil, false, pkgerrors.Wrap(pkgerrors.CodeDatabaseError, result.Error, "写入入站 Integration Log 失败")
	}
	if result.RowsAffected == 1 {
		return log, true, nil
	}
	var existing model.IntegrationLog
	if err := r.db.WithContext(ctx).Where(
		"provider = ? AND operation = ? AND idempotency_key = ?", input.Provider, input.Operation, input.IdempotencyKey,
	).First(&existing).Error; err != nil {
		return nil, false, pkgerrors.Wrap(pkgerrors.CodeDatabaseError, err, "读取重复入站 Integration Log 失败")
	}
	if existing.ContentHash != hex.EncodeToString(hash[:]) {
		return nil, false, pkgerrors.New(pkgerrors.CodeConflict, "入站幂等标识对应的载荷不一致")
	}
	return &existing, false, nil
}

// recordAuditEvent 为新的外部交互建立稳定审计关联；审计失败不丢失外部事实。
func (r *Repository) recordAuditEvent(ctx context.Context, actionCode, integrationID, provider, direction, operation, resourceType string, resourceID, resourceKey, correlationID *string) *uint {
	if r == nil || r.db == nil || r.audit == nil {
		zap.L().Warn("Integration Log 缺少审计关联", zap.String("integration_id", integrationID), zap.String("reason", "审计 Writer 未配置"))
		return nil
	}
	value := auditcontext.From(ctx)
	if !validAuditOrigin(value.ActorKind, value.ActorID, value.Source) {
		value.ActorKind = constants.AuditActorSystemTask
		value.ActorID = "integration_log"
		value.Source = constants.AuditSourceWorker
	}
	event, err := r.audit.AppendAndGet(ctx, r.db, audit.AppendInput{
		EventID:    "integration:" + integrationID,
		ActionCode: actionCode, Summary: "记录外部交互审计关联",
		Actor:  audit.ActorInput{Kind: value.ActorKind, ID: value.ActorID, Name: value.ActorName, ShopID: value.ActorShopID, EnterpriseID: value.ActorEnterpriseID},
		Source: value.Source, ScopeType: constants.AuditScopePlatform,
		Result: constants.AuditResultSuccess, RequestID: textValue(correlationID), CorrelationID: textValue(correlationID),
		Resources: []audit.ResourceInput{{
			Type: constants.AuditResourceIntegrationLog, Key: integrationID, DisplayName: operation,
			Relation: constants.AuditResourceRelationPrimary, Role: constants.AuditResourceRoleWorkerIntegration,
			IdentitySnapshot: map[string]any{
				"integration_id": integrationID, "provider": provider, "direction": direction, "operation": operation,
				"resource_type": resourceType, "resource_id": textValue(resourceID), "resource_key": textValue(resourceKey), "correlation_id": textValue(correlationID),
			},
		}},
	})
	if err != nil {
		zap.L().Warn("Integration Log 缺少审计关联", zap.String("integration_id", integrationID), zap.Error(err))
		return nil
	}
	return &event.ID
}

func (r *Repository) auditEventIDForSeries(ctx context.Context, triggerSeries string) *uint {
	if r == nil || r.db == nil || triggerSeries == "" {
		return nil
	}
	var log model.IntegrationLog
	if err := r.db.WithContext(ctx).Where("trigger_series = ? AND audit_event_id IS NOT NULL", triggerSeries).Order("attempt DESC").First(&log).Error; err != nil {
		return nil
	}
	return log.AuditEventID
}

func validAuditOrigin(actorKind, actorID, source string) bool {
	if actorID == "" {
		return false
	}
	switch source {
	case constants.AuditSourceAdminAPI:
		return actorKind == constants.AuditActorAccount
	case constants.AuditSourcePersonalAPI:
		return actorKind == constants.AuditActorPersonalCustomer
	case constants.AuditSourceOpenAPI:
		return actorKind == constants.AuditActorOpenAPI
	case constants.AuditSourceCallback:
		return actorKind == constants.AuditActorExternalSystem
	case constants.AuditSourceScheduler:
		return actorKind == constants.AuditActorScheduledJob
	case constants.AuditSourceWorker:
		return actorKind == constants.AuditActorSystemTask
	default:
		return false
	}
}

func textValue(value *string) string {
	if value == nil {
		return ""
	}
	return *value
}

// ClaimExpiredInboundPending 原子认领已超过处理租约的入站 pending 记录。
func (r *Repository) ClaimExpiredInboundPending(ctx context.Context, integrationID string, lease time.Duration) (bool, error) {
	if r == nil || r.db == nil {
		return false, pkgerrors.New(pkgerrors.CodeInvalidStatus, "Integration Log 数据库未配置")
	}
	if strings.TrimSpace(integrationID) == "" || lease <= 0 {
		return false, pkgerrors.New(pkgerrors.CodeInvalidParam, "入站 Integration Log 恢复参数无效")
	}
	now := r.now().UTC()
	result := r.db.WithContext(ctx).Model(&model.IntegrationLog{}).
		Where("integration_id = ? AND direction = ? AND result = ? AND (started_at IS NULL OR started_at <= ?)",
			integrationID, constants.IntegrationDirectionInbound, constants.IntegrationResultPending, now.Add(-lease)).
		Updates(map[string]any{
			"started_at": now,
			"attempt":    gorm.Expr("attempt + 1"),
			"updated_at": now,
		})
	if result.Error != nil {
		return false, pkgerrors.Wrap(pkgerrors.CodeDatabaseError, result.Error, "认领待恢复入站 Integration Log 失败")
	}
	return result.RowsAffected == 1, nil
}

// ClaimFailedInbound 原子认领失败的入站回调并恢复为待处理状态。
func (r *Repository) ClaimFailedInbound(ctx context.Context, integrationID string) (bool, error) {
	if r == nil || r.db == nil {
		return false, pkgerrors.New(pkgerrors.CodeInvalidStatus, "Integration Log 数据库未配置")
	}
	if strings.TrimSpace(integrationID) == "" {
		return false, pkgerrors.New(pkgerrors.CodeInvalidParam, "入站 Integration Log 恢复参数无效")
	}
	now := r.now().UTC()
	result := r.db.WithContext(ctx).Model(&model.IntegrationLog{}).
		Where("integration_id = ? AND direction = ? AND result = ?", integrationID, constants.IntegrationDirectionInbound, constants.IntegrationResultFailed).
		Updates(map[string]any{
			"result": constants.IntegrationResultPending, "started_at": now,
			"attempt": gorm.Expr("attempt + 1"), "updated_at": now,
			"http_status": nil, "provider_code": nil, "provider_message": nil,
			"response_summary": nil, "duration_ms": 0, "state_changed": false, "recovery_strategy": nil,
		})
	if result.Error != nil {
		return false, pkgerrors.Wrap(pkgerrors.CodeDatabaseError, result.Error, "认领失败入站 Integration Log 失败")
	}
	return result.RowsAffected == 1, nil
}

func validateAttempt(input Attempt) error {
	if input.Provider == "" || input.Operation == "" {
		return pkgerrors.New(pkgerrors.CodeInvalidParam, "Integration Log 提供方和操作不能为空")
	}
	if input.Direction != constants.IntegrationDirectionInbound && input.Direction != constants.IntegrationDirectionOutbound {
		return pkgerrors.New(pkgerrors.CodeInvalidParam, "Integration Log 方向无效")
	}
	if input.InitialResult != "" && input.InitialResult != constants.IntegrationResultPending && !isUnsentResult(input.InitialResult) {
		return pkgerrors.New(pkgerrors.CodeInvalidParam, "Integration Log 初始结果只能是待处理或未发送终态")
	}
	if !validGeneratedString(input.IntegrationID, constants.IntegrationIDMaxLength) ||
		!validOptionalString(input.TriggerSeries, constants.IntegrationTriggerSeriesMaxLength) ||
		!validOptionalString(input.CorrelationID, constants.IntegrationCorrelationIDMaxLength) ||
		!validOptionalString(input.ResourceID, constants.IntegrationResourceIDMaxLength) ||
		!validOptionalString(input.ResourceKey, constants.IntegrationResourceKeyMaxLength) {
		return pkgerrors.New(pkgerrors.CodeInvalidParam, "Integration Log 链路或资源标识无效")
	}
	return nil
}

func validGeneratedString(value string, maxLength int) bool {
	return value == "" || validRequiredString(value, maxLength)
}

func validRequiredString(value string, maxLength int) bool {
	return strings.TrimSpace(value) == value && value != "" && utf8.RuneCountInString(value) <= maxLength
}

func validOptionalString(value *string, maxLength int) bool {
	return value == nil || validRequiredString(*value, maxLength)
}

func isTerminalResult(result string) bool {
	switch result {
	case constants.IntegrationResultSuccess, constants.IntegrationResultFailed, constants.IntegrationResultUnknown,
		constants.IntegrationResultNotFound, constants.IntegrationResultInvalidPayload, constants.IntegrationResultIgnored,
		constants.IntegrationResultConflict,
		constants.IntegrationResultMerged, constants.IntegrationResultRateLimited, constants.IntegrationResultCompleted,
		constants.IntegrationResultCancelled:
		return true
	default:
		return false
	}
}

func isUnsentResult(result string) bool {
	switch result {
	case constants.IntegrationResultIgnored, constants.IntegrationResultMerged, constants.IntegrationResultRateLimited,
		constants.IntegrationResultCompleted, constants.IntegrationResultCancelled:
		return true
	default:
		return false
	}
}

func marshalSummary(value any) (datatypes.JSON, error) {
	if value == nil {
		return nil, nil
	}
	encoded, err := sanitizer.MarshalSummary(value)
	return datatypes.JSON(encoded), err
}

func optionalString(value string) *string {
	if value == "" {
		return nil
	}
	return &value
}

func sanitizedOptionalText(value *string) *string {
	if value == nil {
		return nil
	}
	sanitized := sanitizer.SanitizeText(*value)
	return &sanitized
}