// 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"

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

	"github.com/break/junhong_cmp_fiber/internal/model"
	"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
	ResponseSummary  any
	DurationMS       int64
	StateChanged     bool
	AuditEventID     *uint
	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
}

// 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
}

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

// 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.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: input.ExternalID, ResourceType: resourceType,
		ResourceID: input.ResourceID, ResourceKey: input.ResourceKey, TriggerSource: input.TriggerSource,
		TriggerScene: 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: input.RecoveryStrategy,
	}
	if err := r.db.WithContext(ctx).Create(log).Error; err != nil {
		return nil, pkgerrors.Wrap(pkgerrors.CodeDatabaseError, err, "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 integrationID == "" || !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")
	}
	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 completion.ProviderMessage != "" {
		updates["provider_message"] = sanitizer.TextSummary(completion.ProviderMessage)
	}
	if completion.AuditEventID != nil {
		updates["audit_event_id"] = completion.AuditEventID
	}
	if completion.RecoveryStrategy != "" {
		updates["recovery_strategy"] = 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 == "" || len(input.RawPayload) == 0 {
		return nil, false, pkgerrors.New(pkgerrors.CodeInvalidParam, "入站 Integration Log 参数无效")
	}
	if input.IntegrationID == "" {
		input.IntegrationID = uuid.NewString()
	}
	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: optionalString(input.ExternalID), ResourceType: optionalString(input.ResourceType),
		ResourceID: input.ResourceID, ResourceKey: input.ResourceKey, StartedAt: &now, Attempt: 1,
		Result: constants.IntegrationResultPending, RequestSummary: summary,
		ContentHash: hex.EncodeToString(hash[:]), RequestID: input.RequestID, CorrelationID: input.CorrelationID,
	}
	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
}

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")
	}
	return nil
}

func isTerminalResult(result string) bool {
	switch result {
	case constants.IntegrationResultSuccess, constants.IntegrationResultFailed, constants.IntegrationResultUnknown,
		constants.IntegrationResultNotFound, constants.IntegrationResultInvalidPayload, constants.IntegrationResultIgnored,
		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
}