package service

import (
	"errors"
	"fmt"
	"time"

	"github.com/topfans/backend/pkg/models"
	pb "github.com/topfans/backend/pkg/proto/gallery"
	"github.com/topfans/backend/services/galleryService/client"
	"github.com/topfans/backend/services/galleryService/config"
	"github.com/topfans/backend/services/galleryService/repository"
)

// SlotService 展位服务接口
type SlotService interface {
	UnlockSlot(userID, starID int64) (*pb.UnlockSlotData, error)
}

// slotService 展位服务实现
type slotService struct {
	repo       repository.GalleryRepository
	userClient client.UserRPCClient
}

// NewSlotService 创建展位服务实例
func NewSlotService(repo repository.GalleryRepository, userClient client.UserRPCClient) SlotService {
	return &slotService{
		repo:       repo,
		userClient: userClient,
	}
}

// UnlockSlot 解锁/购买新展位（优先等级解锁）
func (s *slotService) UnlockSlot(userID, starID int64) (*pb.UnlockSlotData, error) {
	// 1. 获取粉丝档案（等级、水晶余额）
	if s.userClient == nil {
		return nil, errors.New("user client not initialized")
	}

	profile, err := s.userClient.GetFanProfile(userID, starID)
	if err != nil {
		return nil, err
	}

	// 2. 查询当前展位数
	currentSlotCount, err := s.repo.GetSlotCount(userID, starID)
	if err != nil {
		return nil, err
	}

	nextSlotIndex := int(currentSlotCount) + 1

	// 3. 检查是否已达到最大展位数
	if nextSlotIndex > config.GalleryRules.MaxSlotCount {
		return nil, errors.New("已达到最大展位数")
	}

	// 4. 获取解锁规则
	requiredLevel, hasLevel := config.GalleryRules.UnlockLevelBySlot[nextSlotIndex]
	requiredCrystal, hasCrystal := config.GalleryRules.UnlockCrystalBySlot[nextSlotIndex]

	// 如果没有配置解锁规则，返回错误
	if !hasLevel && !hasCrystal {
		return nil, errors.New("该展位无法解锁")
	}

	// 5. 优先检查等级解锁
	if hasLevel && profile.Level >= int32(requiredLevel) {
		// 等级足够，直接解锁（不消耗水晶）
		_, err := s.createUnlockedSlot(userID, starID, nextSlotIndex, "level", requiredLevel)
		if err != nil {
			return nil, err
		}

		return &pb.UnlockSlotData{
			SlotTotal:      int32(nextSlotIndex),
			CrystalBalance: profile.CrystalBalance, // 水晶余额不变
		}, nil
	}

	// 6. 等级不够，检查水晶购买
	if hasCrystal && profile.CrystalBalance >= int64(requiredCrystal) {
		// 扣除水晶
		newBalance, err := s.userClient.UpdateCrystalBalance(userID, starID, -int64(requiredCrystal),
			"slot_purchase", "", fmt.Sprintf("购买展位 #%d", nextSlotIndex))
		if err != nil {
			return nil, err
		}

		// 创建展位
		_, err = s.createUnlockedSlot(userID, starID, nextSlotIndex, "crystal", requiredCrystal)
		if err != nil {
			// 如果创建失败，需要回滚水晶扣除
			// TODO: 考虑使用分布式事务或补偿机制
			return nil, err
		}

		return &pb.UnlockSlotData{
			SlotTotal:      int32(nextSlotIndex),
			CrystalBalance: newBalance, // 返回扣除后的水晶余额
		}, nil
	}

	// 7. 都不满足，返回错误
	return nil, errors.New("等级和水晶余额都不足，无法解锁")
}

// createUnlockedSlot 创建已解锁的展位
func (s *slotService) createUnlockedSlot(userID, starID int64, slotIndex int, unlockType string, unlockValue int) (*models.BoothSlot, error) {
	now := time.Now().UnixMilli()

	// 获取真实的 fan_profile ID
	profile, err := s.userClient.GetFanProfile(userID, starID)
	if err != nil {
		return nil, fmt.Errorf("failed to get fan profile: %w", err)
	}

	slot := &models.BoothSlot{
		HostProfileID: profile.ID,
		UserID:        userID,
		StarID:        starID,
		SlotIndex:     slotIndex,
		Visibility:    "public", // 新解锁的展位默认为公有
		IsEnabled:     true,
		UnlockType:    unlockType,
		UnlockValue:   unlockValue,
		CreatedAt:     now,
		UpdatedAt:     now,
	}

	err = s.repo.CreateSlot(slot)
	if err != nil {
		return nil, err
	}

	return slot, nil
}