package product

import (
	"context"
	"fmt"

	"github.com/shopspring/decimal"

	"go.uber.org/zap"

	"tyapi-server/internal/application/product/dto/commands"
	appQueries "tyapi-server/internal/application/product/dto/queries"
	"tyapi-server/internal/application/product/dto/responses"
	"tyapi-server/internal/domains/product/entities"
	repoQueries "tyapi-server/internal/domains/product/repositories/queries"
	product_service "tyapi-server/internal/domains/product/services"
)

// SubscriptionApplicationServiceImpl 订阅应用服务实现
// 负责业务流程编排、事务管理、数据转换，不直接操作仓库
type SubscriptionApplicationServiceImpl struct {
	productSubscriptionService *product_service.ProductSubscriptionService
	logger                     *zap.Logger
}

// NewSubscriptionApplicationService 创建订阅应用服务
func NewSubscriptionApplicationService(
	productSubscriptionService *product_service.ProductSubscriptionService,
	logger *zap.Logger,
) SubscriptionApplicationService {
	return &SubscriptionApplicationServiceImpl{
		productSubscriptionService: productSubscriptionService,
		logger:                     logger,
	}
}

// UpdateSubscriptionPrice 更新订阅价格
// 业务流程：1. 获取订阅 2. 更新价格 3. 保存订阅
func (s *SubscriptionApplicationServiceImpl) UpdateSubscriptionPrice(ctx context.Context, cmd *commands.UpdateSubscriptionPriceCommand) error {
	// 1. 获取现有订阅
	subscription, err := s.productSubscriptionService.GetSubscriptionByID(ctx, cmd.ID)
	if err != nil {
		return err
	}

	// 2. 更新订阅价格
	subscription.Price = decimal.NewFromFloat(cmd.Price)

	// 3. 保存订阅
	// 这里需要扩展领域服务来支持更新操作
	// 暂时返回错误
	return fmt.Errorf("更新订阅价格功能暂未实现")
}

// CreateSubscription 创建订阅
// 业务流程：1. 创建订阅
func (s *SubscriptionApplicationServiceImpl) CreateSubscription(ctx context.Context, cmd *commands.CreateSubscriptionCommand) error {
	_, err := s.productSubscriptionService.CreateSubscription(ctx, cmd.UserID, cmd.ProductID)
	return err
}

// GetSubscriptionByID 根据ID获取订阅
// 业务流程：1. 获取订阅信息 2. 构建响应数据
func (s *SubscriptionApplicationServiceImpl) GetSubscriptionByID(ctx context.Context, query *appQueries.GetSubscriptionQuery) (*responses.SubscriptionInfoResponse, error) {
	subscription, err := s.productSubscriptionService.GetSubscriptionByID(ctx, query.ID)
	if err != nil {
		return nil, err
	}

	return s.convertToSubscriptionInfoResponse(subscription), nil
}

// ListSubscriptions 获取订阅列表
// 业务流程：1. 获取订阅列表 2. 构建响应数据
func (s *SubscriptionApplicationServiceImpl) ListSubscriptions(ctx context.Context, query *appQueries.ListSubscriptionsQuery) (*responses.SubscriptionListResponse, error) {
	repoQuery := &repoQueries.ListSubscriptionsQuery{
		Page:     query.Page,
		PageSize: query.PageSize,
	}
	subscriptions, total, err := s.productSubscriptionService.ListSubscriptions(ctx, repoQuery)
	if err != nil {
		return nil, err
	}
	items := make([]responses.SubscriptionInfoResponse, len(subscriptions))
	for i := range subscriptions {
		resp := s.convertToSubscriptionInfoResponse(subscriptions[i])
		if resp != nil {
			items[i] = *resp // 解引用指针
		}
	}
	return &responses.SubscriptionListResponse{
		Total: total,
		Page:  query.Page,
		Size:  query.PageSize,
		Items: items,
	}, nil
}

// GetUserSubscriptions 获取用户订阅
// 业务流程：1. 获取用户订阅 2. 构建响应数据
func (s *SubscriptionApplicationServiceImpl) GetUserSubscriptions(ctx context.Context, query *appQueries.GetUserSubscriptionsQuery) ([]*responses.SubscriptionInfoResponse, error) {
	subscriptions, err := s.productSubscriptionService.GetUserSubscriptions(ctx, query.UserID)
	if err != nil {
		return nil, err
	}

	// 转换为响应对象
	items := make([]*responses.SubscriptionInfoResponse, len(subscriptions))
	for i := range subscriptions {
		items[i] = s.convertToSubscriptionInfoResponse(subscriptions[i])
	}

	return items, nil
}

// GetProductSubscriptions 获取产品订阅
// 业务流程：1. 获取产品订阅 2. 构建响应数据
func (s *SubscriptionApplicationServiceImpl) GetProductSubscriptions(ctx context.Context, query *appQueries.GetProductSubscriptionsQuery) ([]*responses.SubscriptionInfoResponse, error) {
	// 这里需要扩展领域服务来支持按产品查询订阅
	// 暂时返回空列表
	return []*responses.SubscriptionInfoResponse{}, nil
}

// GetSubscriptionUsage 获取订阅使用情况
// 业务流程：1. 获取订阅使用情况 2. 构建响应数据
func (s *SubscriptionApplicationServiceImpl) GetSubscriptionUsage(ctx context.Context, subscriptionID string) (*responses.SubscriptionUsageResponse, error) {
	subscription, err := s.productSubscriptionService.GetSubscriptionByID(ctx, subscriptionID)
	if err != nil {
		return nil, err
	}

	return &responses.SubscriptionUsageResponse{
		ID:      subscription.ID,
		ProductID: subscription.ProductID,
		APIUsed: subscription.APIUsed,
	}, nil
}

// GetSubscriptionStats 获取订阅统计信息
// 业务流程：1. 获取订阅统计 2. 构建响应数据
func (s *SubscriptionApplicationServiceImpl) GetSubscriptionStats(ctx context.Context) (*responses.SubscriptionStatsResponse, error) {
	// 这里需要扩展领域服务来支持统计功能
	// 暂时返回默认值
	return &responses.SubscriptionStatsResponse{
		TotalSubscriptions: 0,
		TotalRevenue: 0,
	}, nil
}

// convertToSubscriptionInfoResponse 转换为订阅信息响应
func (s *SubscriptionApplicationServiceImpl) convertToSubscriptionInfoResponse(subscription *entities.Subscription) *responses.SubscriptionInfoResponse {
	return &responses.SubscriptionInfoResponse{
		ID:        subscription.ID,
		UserID:    subscription.UserID,
		ProductID: subscription.ProductID,
		Price:     subscription.Price.InexactFloat64(),
		Product:   s.convertToProductSimpleResponse(subscription.Product),
		APIUsed:   subscription.APIUsed,
		CreatedAt: subscription.CreatedAt,
		UpdatedAt: subscription.UpdatedAt,
	}
}

// convertToProductSimpleResponse 转换为产品简单信息响应
func (s *SubscriptionApplicationServiceImpl) convertToProductSimpleResponse(product *entities.Product) *responses.ProductSimpleResponse {
	return &responses.ProductSimpleResponse{
		ID:          product.ID,
		Name:        product.Name,
		Code:        product.Code,
		Description: product.Description,
		Price:       product.Price.InexactFloat64(),
		Category:    s.convertToCategorySimpleResponse(product.Category),
		IsPackage:   product.IsPackage,
	}
}

// convertToCategorySimpleResponse 转换为分类简单信息响应
func (s *SubscriptionApplicationServiceImpl) convertToCategorySimpleResponse(category *entities.ProductCategory) *responses.CategorySimpleResponse {
	return &responses.CategorySimpleResponse{
		ID:   category.ID,
		Name: category.Name,
	}
}