package state_machine

import (
	"context"
	"fmt"
	"time"

	"tyapi-server/internal/domains/certification/entities"
	"tyapi-server/internal/domains/certification/enums"
	"tyapi-server/internal/domains/certification/repositories"

	"go.uber.org/zap"
)

// CertificationStateMachine 认证状态机
// 负责管理认证流程的状态转换、业务规则验证和事件发布
type CertificationStateMachine struct {
	configManager  *StateConfigManager
	repository     repositories.CertificationCommandRepository
	eventPublisher interface{}  // TODO: 使用 interfaces.EventPublisher
	logger         *zap.Logger
}

// NewCertificationStateMachine 创建认证状态机
func NewCertificationStateMachine(
	repository repositories.CertificationCommandRepository,
	eventPublisher interface{}, // TODO: 使用 interfaces.EventPublisher
	logger *zap.Logger,
) *CertificationStateMachine {
	return &CertificationStateMachine{
		configManager:  NewStateConfigManager(),
		repository:     repository,
		eventPublisher: eventPublisher,
		logger:         logger,
	}
}

// StateTransitionRequest 状态转换请求
type StateTransitionRequest struct {
	CertificationID string                     `json:"certification_id"`
	TargetStatus    enums.CertificationStatus `json:"target_status"`
	Actor           enums.ActorType           `json:"actor"`
	ActorID         string                     `json:"actor_id"`
	Reason          string                     `json:"reason"`
	Context         map[string]interface{}     `json:"context"`
	AllowRollback   bool                       `json:"allow_rollback"`
}

// StateTransitionResult 状态转换结果
type StateTransitionResult struct {
	Success         bool                       `json:"success"`
	OldStatus       enums.CertificationStatus `json:"old_status"`
	NewStatus       enums.CertificationStatus `json:"new_status"`
	Message         string                     `json:"message"`
	TransitionedAt  time.Time                  `json:"transitioned_at"`
	Events          []interface{}              `json:"events,omitempty"`
}

// CanTransition 检查是否可以执行状态转换
func (sm *CertificationStateMachine) CanTransition(
	cert *entities.Certification,
	targetStatus enums.CertificationStatus,
	actor enums.ActorType,
) (bool, string) {
	// 1. 检查基本状态转换规则
	canTransition, message := sm.configManager.CanTransition(cert.Status, targetStatus, actor)
	if !canTransition {
		return false, message
	}

	// 2. 检查认证实体的业务规则
	if canTransition, message := cert.CanTransitionTo(targetStatus, actor); !canTransition {
		return false, message
	}

	// 3. 检查是否为最终状态
	if cert.IsFinalStatus() {
		return false, "认证已完成，无法进行状态转换"
	}

	return true, ""
}

// ExecuteTransition 执行状态转换
func (sm *CertificationStateMachine) ExecuteTransition(
	ctx context.Context,
	req *StateTransitionRequest,
) (*StateTransitionResult, error) {
	sm.logger.Info("开始执行状态转换",
		zap.String("certification_id", req.CertificationID),
		zap.String("target_status", string(req.TargetStatus)),
		zap.String("actor", string(req.Actor)),
		zap.String("actor_id", req.ActorID))

	// 1. 加载认证聚合根
	cert, err := sm.loadCertification(ctx, req.CertificationID)
	if err != nil {
		return sm.createFailureResult(cert.Status, req.TargetStatus, fmt.Sprintf("加载认证信息失败: %s", err.Error())), err
	}

	oldStatus := cert.Status

	// 2. 验证转换合法性
	if canTransition, message := sm.CanTransition(cert, req.TargetStatus, req.Actor); !canTransition {
		return sm.createFailureResult(oldStatus, req.TargetStatus, message), fmt.Errorf("状态转换验证失败: %s", message)
	}

	// 3. 验证业务规则
	if err := sm.validateBusinessRules(cert, req); err != nil {
		return sm.createFailureResult(oldStatus, req.TargetStatus, fmt.Sprintf("业务规则验证失败: %s", err.Error())), err
	}

	// 4. 执行状态转换
	if err := cert.TransitionTo(req.TargetStatus, req.Actor, req.ActorID, req.Reason); err != nil {
		return sm.createFailureResult(oldStatus, req.TargetStatus, fmt.Sprintf("状态转换执行失败: %s", err.Error())), err
	}

	// 5. 保存到数据库
	if err := sm.repository.Update(ctx, *cert); err != nil {
		// 如果保存失败，需要回滚状态
		sm.logger.Error("状态转换保存失败，尝试回滚",
			zap.String("certification_id", req.CertificationID),
			zap.Error(err))
		
		if req.AllowRollback {
			if rollbackErr := sm.rollbackStateTransition(ctx, cert, oldStatus, req.Actor, req.ActorID); rollbackErr != nil {
				sm.logger.Error("状态回滚失败", zap.Error(rollbackErr))
			}
		}
		
		return sm.createFailureResult(oldStatus, req.TargetStatus, fmt.Sprintf("保存状态转换失败: %s", err.Error())), err
	}

	// 6. 发布领域事件
	events := cert.GetDomainEvents()
	for _, event := range events {
		// TODO: 实现事件发布
		// if err := sm.eventPublisher.PublishEvent(ctx, event); err != nil {
		// 	sm.logger.Error("发布领域事件失败",
		// 		zap.String("certification_id", req.CertificationID),
		// 		zap.Error(err))
		// }
		sm.logger.Info("领域事件待发布",
			zap.String("certification_id", req.CertificationID),
			zap.Any("event", event))
	}

	// 7. 清理领域事件
	cert.ClearDomainEvents()

	// 8. 记录成功日志
	sm.logger.Info("状态转换执行成功",
		zap.String("certification_id", req.CertificationID),
		zap.String("from_status", string(oldStatus)),
		zap.String("to_status", string(req.TargetStatus)),
		zap.String("actor", string(req.Actor)))

	// 9. 返回成功结果
	return &StateTransitionResult{
		Success:        true,
		OldStatus:      oldStatus,
		NewStatus:      req.TargetStatus,
		Message:        "状态转换成功",
		TransitionedAt: time.Now(),
		Events:         events,
	}, nil
}

// GetValidTransitions 获取有效的状态转换
func (sm *CertificationStateMachine) GetValidTransitions(
	cert *entities.Certification,
	actor enums.ActorType,
) []*StateTransitionRule {
	return sm.configManager.GetAllowedTransitions(cert.Status, actor)
}

// GetStateInfo 获取状态信息
func (sm *CertificationStateMachine) GetStateInfo(status enums.CertificationStatus) *StateConfig {
	return sm.configManager.GetStateConfig(status)
}

// ValidateBusinessRules 验证业务规则
func (sm *CertificationStateMachine) ValidateBusinessRules(
	cert *entities.Certification,
	req *StateTransitionRequest,
) error {
	return sm.validateBusinessRules(cert, req)
}

// IsUserActionRequired 检查是否需要用户操作
func (sm *CertificationStateMachine) IsUserActionRequired(status enums.CertificationStatus) bool {
	return sm.configManager.IsUserActionRequired(status)
}

// GetProgressPercentage 获取进度百分比
func (sm *CertificationStateMachine) GetProgressPercentage(status enums.CertificationStatus) int {
	return sm.configManager.GetStateProgress(status)
}

// ================ 私有方法 ================

// loadCertification 加载认证聚合根
func (sm *CertificationStateMachine) loadCertification(ctx context.Context, certificationID string) (*entities.Certification, error) {
	// 这里需要通过查询仓储获取认证信息
	// 由于当前只有命令仓储，这里使用简单的方法
	// 在实际实现中，应该使用查询仓储
	cert := &entities.Certification{ID: certificationID}
	
	// TODO: 实现从查询仓储加载认证信息
	// cert, err := sm.queryRepository.GetByID(ctx, certificationID)
	// if err != nil {
	//     return nil, fmt.Errorf("认证信息不存在: %w", err)
	// }
	
	return cert, nil
}

// validateBusinessRules 验证业务规则
func (sm *CertificationStateMachine) validateBusinessRules(
	cert *entities.Certification,
	req *StateTransitionRequest,
) error {
	// 获取转换规则
	rule := sm.configManager.GetTransitionRule(cert.Status, req.TargetStatus)
	if rule == nil {
		return fmt.Errorf("找不到状态转换规则")
	}

	// 如果不需要验证，直接返回
	if !rule.RequiresValidation {
		return nil
	}

	// 构建验证上下文
	context := make(map[string]interface{})
	
	// 添加认证基本信息
	context["certification_id"] = cert.ID
	context["user_id"] = cert.UserID
	context["current_status"] = string(cert.Status)
	context["retry_count"] = cert.RetryCount
	context["auth_flow_id"] = cert.AuthFlowID
	
	// 添加请求中的上下文信息
	for key, value := range req.Context {
		context[key] = value
	}

	// 执行业务规则验证
	return sm.configManager.ValidateBusinessRules(rule, context)
}

// rollbackStateTransition 回滚状态转换
func (sm *CertificationStateMachine) rollbackStateTransition(
	ctx context.Context,
	cert *entities.Certification,
	originalStatus enums.CertificationStatus,
	actor enums.ActorType,
	actorID string,
) error {
	sm.logger.Info("开始回滚状态转换",
		zap.String("certification_id", cert.ID),
		zap.String("original_status", string(originalStatus)),
		zap.String("current_status", string(cert.Status)))

	// 直接设置回原状态（跳过业务规则验证）
	cert.Status = originalStatus
	
	// 更新审计信息
	now := time.Now()
	cert.LastTransitionAt = &now
	cert.LastTransitionBy = actor
	cert.LastTransitionActor = actorID

	// 保存回滚结果
	if err := sm.repository.Update(ctx, *cert); err != nil {
		return fmt.Errorf("保存回滚状态失败: %w", err)
	}

	sm.logger.Info("状态转换回滚成功",
		zap.String("certification_id", cert.ID),
		zap.String("rollback_to_status", string(originalStatus)))

	return nil
}

// createFailureResult 创建失败结果
func (sm *CertificationStateMachine) createFailureResult(
	oldStatus, targetStatus enums.CertificationStatus,
	message string,
) *StateTransitionResult {
	return &StateTransitionResult{
		Success:        false,
		OldStatus:      oldStatus,
		NewStatus:      targetStatus,
		Message:        message,
		TransitionedAt: time.Now(),
		Events:         []interface{}{},
	}
}

// ================ 状态转换快捷方法 ================

// TransitionToInfoSubmitted 转换到已提交企业信息状态
func (sm *CertificationStateMachine) TransitionToInfoSubmitted(
	ctx context.Context,
	certificationID string,
	actor enums.ActorType,
	actorID string,
	enterpriseInfo interface{},
) (*StateTransitionResult, error) {
	req := &StateTransitionRequest{
		CertificationID: certificationID,
		TargetStatus:    enums.StatusInfoSubmitted,
		Actor:           actor,
		ActorID:         actorID,
		Reason:          "用户提交企业信息",
		Context: map[string]interface{}{
			"enterprise_info": enterpriseInfo,
		},
		AllowRollback: true,
	}
	
	return sm.ExecuteTransition(ctx, req)
}

// TransitionToEnterpriseVerified 转换到已企业认证状态
func (sm *CertificationStateMachine) TransitionToEnterpriseVerified(
	ctx context.Context,
	certificationID string,
	authFlowID string,
) (*StateTransitionResult, error) {
	req := &StateTransitionRequest{
		CertificationID: certificationID,
		TargetStatus:    enums.StatusEnterpriseVerified,
		Actor:           enums.ActorTypeEsign,
		ActorID:         "esign_system",
		Reason:          "e签宝企业认证成功",
		Context: map[string]interface{}{
			"auth_flow_id": authFlowID,
		},
		AllowRollback: false,
	}
	
	return sm.ExecuteTransition(ctx, req)
}

// TransitionToInfoRejected 转换到企业信息被拒绝状态
func (sm *CertificationStateMachine) TransitionToInfoRejected(
	ctx context.Context,
	certificationID string,
	failureReason enums.FailureReason,
	failureMessage string,
) (*StateTransitionResult, error) {
	req := &StateTransitionRequest{
		CertificationID: certificationID,
		TargetStatus:    enums.StatusInfoRejected,
		Actor:           enums.ActorTypeEsign,
		ActorID:         "esign_system",
		Reason:          "e签宝企业认证失败",
		Context: map[string]interface{}{
			"failure_reason":  failureReason,
			"failure_message": failureMessage,
		},
		AllowRollback: false,
	}
	
	return sm.ExecuteTransition(ctx, req)
}

// TransitionToContractApplied 转换到已申请合同状态
func (sm *CertificationStateMachine) TransitionToContractApplied(
	ctx context.Context,
	certificationID string,
	actor enums.ActorType,
	actorID string,
) (*StateTransitionResult, error) {
	req := &StateTransitionRequest{
		CertificationID: certificationID,
		TargetStatus:    enums.StatusContractApplied,
		Actor:           actor,
		ActorID:         actorID,
		Reason:          "用户申请合同签署",
		Context:         map[string]interface{}{},
		AllowRollback:   true,
	}
	
	return sm.ExecuteTransition(ctx, req)
}

// TransitionToContractSigned 转换到已签署合同状态（认证完成）
func (sm *CertificationStateMachine) TransitionToContractSigned(
	ctx context.Context,
	certificationID string,
	contractURL string,
) (*StateTransitionResult, error) {
	req := &StateTransitionRequest{
		CertificationID: certificationID,
		TargetStatus:    enums.StatusContractSigned,
		Actor:           enums.ActorTypeEsign,
		ActorID:         "esign_system",
		Reason:          "e签宝合同签署成功，认证完成",
		Context: map[string]interface{}{
			"contract_url": contractURL,
		},
		AllowRollback: false,
	}
	
	return sm.ExecuteTransition(ctx, req)
}

// TransitionToContractRejected 转换到合同被拒签状态
func (sm *CertificationStateMachine) TransitionToContractRejected(
	ctx context.Context,
	certificationID string,
	failureReason enums.FailureReason,
	failureMessage string,
) (*StateTransitionResult, error) {
	req := &StateTransitionRequest{
		CertificationID: certificationID,
		TargetStatus:    enums.StatusContractRejected,
		Actor:           enums.ActorTypeEsign,
		ActorID:         "esign_system",
		Reason:          "合同签署失败",
		Context: map[string]interface{}{
			"failure_reason":  failureReason,
			"failure_message": failureMessage,
		},
		AllowRollback: false,
	}
	
	return sm.ExecuteTransition(ctx, req)
}

// TransitionToContractExpired 转换到合同签署超时状态
func (sm *CertificationStateMachine) TransitionToContractExpired(
	ctx context.Context,
	certificationID string,
	failureMessage string,
) (*StateTransitionResult, error) {
	req := &StateTransitionRequest{
		CertificationID: certificationID,
		TargetStatus:    enums.StatusContractExpired,
		Actor:           enums.ActorTypeSystem,
		ActorID:         "timeout_monitor",
		Reason:          "合同签署超时",
		Context: map[string]interface{}{
			"failure_reason":  enums.FailureReasonContractExpired,
			"failure_message": failureMessage,
		},
		AllowRollback: false,
	}
	
	return sm.ExecuteTransition(ctx, req)
}