package livestream

import (
	"context"
	"crypto/hmac"
	"crypto/rand"
	"crypto/sha256"
	"encoding/hex"
	"fmt"
	"math/big"
	"time"

	"bindbox-game/internal/pkg/logger"
	"bindbox-game/internal/repository/mysql"
	"bindbox-game/internal/repository/mysql/model"
	"bindbox-game/internal/service/game"

	"go.uber.org/zap"
	"gorm.io/gorm"
)

// Service 直播间游戏服务接口
type Service interface {
	// CreateActivity 创建直播间活动
	CreateActivity(ctx context.Context, input CreateActivityInput) (*model.LivestreamActivities, error)
	// UpdateActivity 更新活动
	UpdateActivity(ctx context.Context, id int64, input UpdateActivityInput) error
	// GetActivity 获取活动详情
	GetActivity(ctx context.Context, id int64) (*model.LivestreamActivities, error)
	// GetActivityByAccessCode 根据访问码获取活动
	GetActivityByAccessCode(ctx context.Context, code string) (*model.LivestreamActivities, error)
	// ListActivities 活动列表
	ListActivities(ctx context.Context, page, pageSize int, status *int32) ([]*model.LivestreamActivities, int64, error)
	// DeleteActivity 删除活动
	DeleteActivity(ctx context.Context, id int64) error

	// CreatePrizes 批量创建奖品
	CreatePrizes(ctx context.Context, activityID int64, prizes []CreatePrizeInput) error
	// ListPrizes 获取活动奖品列表
	ListPrizes(ctx context.Context, activityID int64) ([]*model.LivestreamPrizes, error)
	// UpdatePrize 更新奖品
	UpdatePrize(ctx context.Context, prizeID int64, input UpdatePrizeInput) error
	// UpdatePrizeSortOrder 更新奖品排序
	UpdatePrizeSortOrder(ctx context.Context, activityID int64, prizeIDs []int64) error
	// DeletePrize 删除奖品
	DeletePrize(ctx context.Context, prizeID int64) error

	// Draw 执行抽奖
	Draw(ctx context.Context, input DrawInput) (*DrawResult, error)
	// ListDrawLogs 获取中奖记录
	ListDrawLogs(ctx context.Context, activityID int64, page, pageSize int, startTime, endTime *time.Time) ([]*model.LivestreamDrawLogs, int64, error)

	// GetActivityByProductID 根据抖店商品ID获取活动
	GetActivityByProductID(ctx context.Context, productID string) (*model.LivestreamActivities, error)

	// GenerateCommitment 为活动生成承诺种子
	GenerateCommitment(ctx context.Context, activityID int64) (int32, error)
	// GetCommitmentSummary 获取活动承诺摘要
	GetCommitmentSummary(ctx context.Context, activityID int64) (*CommitmentSummary, error)
}

type service struct {
	logger        logger.CustomLogger
	repo          mysql.Repo
	ticketSvc     game.TicketService     // 新增：游戏资格服务
	discreteCache *ActivityDiscreteCache // 随机离散位置缓存
}

// New 创建直播间服务
func New(l logger.CustomLogger, repo mysql.Repo, ticketSvc game.TicketService) Service {
	return &service{
		logger:        l,
		repo:          repo,
		ticketSvc:     ticketSvc,
		discreteCache: NewActivityDiscreteCache(),
	}
}

// ========== Input/Output 结构体 ==========

type CreateActivityInput struct {
	Name                string
	StreamerName        string
	StreamerContact     string
	ChannelID           int64
	ChannelCode         string
	DouyinProductID     string
	OrderRewardType     string
	OrderRewardQuantity int32
	TicketPrice         int64
	StartTime           *time.Time
	EndTime             *time.Time
}

type UpdateActivityInput struct {
	Name                string
	StreamerName        string
	StreamerContact     string
	ChannelID           *int64
	ChannelCode         *string
	DouyinProductID     string
	OrderRewardType     string
	OrderRewardQuantity *int32
	TicketPrice         *int64
	Status              *int32
	StartTime           *time.Time
	EndTime             *time.Time
}

type CreatePrizeInput struct {
	Name      string
	Image     string
	Weight    int32
	Quantity  int32
	Level     int32
	ProductID int64 `json:"product_id"`
	CostPrice int64 `json:"cost_price"`
}

type UpdatePrizeInput struct {
	ID        int64  `json:"id"`
	Name      string `json:"name"`
	Level     int32  `json:"level"`
	Weight    int32  `json:"weight"`
	Quantity  int32  `json:"quantity"`
	Image     string `json:"image"`
	ProductID int64  `json:"product_id"`
	CostPrice int64  `json:"cost_price"`
}

type DrawInput struct {
	ActivityID    int64
	DouyinOrderID int64
	ShopOrderID   string
	LocalUserID   int64
	DouyinUserID  string
	UserNickname  string
}

type DrawResult struct {
	Prize    *model.LivestreamPrizes
	DrawLog  *model.LivestreamDrawLogs
	SeedHash string
	Receipt  *DrawReceipt
}

// CommitmentSummary 承诺摘要
type CommitmentSummary struct {
	SeedVersion int32  `json:"seed_version"`
	Algo        string `json:"algo"`
	HasSeed     bool   `json:"has_seed"`
	LenSeed     int    `json:"len_seed_master"`
	LenHash     int    `json:"len_seed_hash"`
	SeedHashHex string `json:"seed_hash_hex"` // 种子哈希的十六进制表示（可公开）
}

// DrawReceipt 抽奖凭证
type DrawReceipt struct {
	SeedVersion int32  `json:"seed_version"`
	Timestamp   int64  `json:"timestamp"`
	Nonce       int64  `json:"nonce"`
	Signature   string `json:"signature"`
	Algorithm   string `json:"algorithm"`
}

// ========== 活动管理 ==========

func (s *service) CreateActivity(ctx context.Context, input CreateActivityInput) (*model.LivestreamActivities, error) {
	// 生成唯一访问码
	accessCode := generateAccessCode()

	activity := &model.LivestreamActivities{
		Name:                input.Name,
		StreamerName:        input.StreamerName,
		StreamerContact:     input.StreamerContact,
		ChannelID:           input.ChannelID,
		ChannelCode:         input.ChannelCode,
		AccessCode:          accessCode,
		DouyinProductID:     input.DouyinProductID,
		OrderRewardType:     input.OrderRewardType,
		OrderRewardQuantity: input.OrderRewardQuantity,
		TicketPrice:         int32(input.TicketPrice),
		Status:              1,
	}

	// 构建要插入的字段列表，排除空的时间字段
	columns := []string{"name", "streamer_name", "streamer_contact", "access_code", "douyin_product_id", "order_reward_type", "order_reward_quantity", "ticket_price", "status"}
	if input.StartTime != nil {
		activity.StartTime = *input.StartTime
		columns = append(columns, "start_time")
	}
	if input.EndTime != nil {
		activity.EndTime = *input.EndTime
		columns = append(columns, "end_time")
	}

	if err := s.repo.GetDbW().WithContext(ctx).Select(columns).Create(activity).Error; err != nil {
		return nil, fmt.Errorf("创建直播间活动失败: %w", err)
	}
	return activity, nil
}

func (s *service) UpdateActivity(ctx context.Context, id int64, input UpdateActivityInput) error {
	updates := make(map[string]any)
	if input.Name != "" {
		updates["name"] = input.Name
	}
	if input.StreamerName != "" {
		updates["streamer_name"] = input.StreamerName
	}
	if input.StreamerContact != "" {
		updates["streamer_contact"] = input.StreamerContact
	}
	if input.ChannelID != nil {
		updates["channel_id"] = *input.ChannelID
	}
	if input.ChannelCode != nil {
		updates["channel_code"] = *input.ChannelCode
	}
	if input.DouyinProductID != "" {
		updates["douyin_product_id"] = input.DouyinProductID
	}
	if input.OrderRewardType != "" {
		updates["order_reward_type"] = input.OrderRewardType
	}
	if input.OrderRewardQuantity != nil {
		updates["order_reward_quantity"] = *input.OrderRewardQuantity
	}
	if input.TicketPrice != nil {
		updates["ticket_price"] = int32(*input.TicketPrice)
	}
	if input.Status != nil {
		updates["status"] = *input.Status
	}
	if input.StartTime != nil {
		updates["start_time"] = *input.StartTime
	}
	if input.EndTime != nil {
		updates["end_time"] = *input.EndTime
	}

	if len(updates) == 0 {
		return nil
	}

	return s.repo.GetDbW().WithContext(ctx).Model(&model.LivestreamActivities{}).
		Where("id = ?", id).Updates(updates).Error
}

func (s *service) GetActivity(ctx context.Context, id int64) (*model.LivestreamActivities, error) {
	var activity model.LivestreamActivities
	if err := s.repo.GetDbR().WithContext(ctx).Where("id = ?", id).First(&activity).Error; err != nil {
		return nil, err
	}
	return &activity, nil
}

func (s *service) GetActivityByAccessCode(ctx context.Context, code string) (*model.LivestreamActivities, error) {
	var activity model.LivestreamActivities
	if err := s.repo.GetDbR().WithContext(ctx).Where("access_code = ? AND deleted_at IS NULL", code).First(&activity).Error; err != nil {
		return nil, err
	}
	return &activity, nil
}

func (s *service) GetActivityByProductID(ctx context.Context, productID string) (*model.LivestreamActivities, error) {
	var activity model.LivestreamActivities
	if err := s.repo.GetDbR().WithContext(ctx).
		Where("douyin_product_id = ? AND status = 1 AND deleted_at IS NULL", productID).
		First(&activity).Error; err != nil {
		return nil, err
	}
	return &activity, nil
}

func (s *service) ListActivities(ctx context.Context, page, pageSize int, status *int32) ([]*model.LivestreamActivities, int64, error) {
	if page <= 0 {
		page = 1
	}
	if pageSize <= 0 {
		pageSize = 20
	}

	db := s.repo.GetDbR().WithContext(ctx).Model(&model.LivestreamActivities{}).Where("deleted_at IS NULL")
	if status != nil {
		db = db.Where("status = ?", *status)
	}

	var total int64
	if err := db.Count(&total).Error; err != nil {
		return nil, 0, err
	}

	var list []*model.LivestreamActivities
	if err := db.Order("id DESC").Offset((page - 1) * pageSize).Limit(pageSize).Find(&list).Error; err != nil {
		return nil, 0, err
	}

	return list, total, nil
}

func (s *service) DeleteActivity(ctx context.Context, id int64) error {
	return s.repo.GetDbW().WithContext(ctx).Delete(&model.LivestreamActivities{}, id).Error
}

// ========== 奖品管理 ==========

func (s *service) CreatePrizes(ctx context.Context, activityID int64, prizes []CreatePrizeInput) error {
	if len(prizes) == 0 {
		return nil
	}

	var models []*model.LivestreamPrizes
	for _, p := range prizes {
		models = append(models, &model.LivestreamPrizes{
			ActivityID: activityID,
			Name:       p.Name,
			Image:      p.Image,
			Weight:     p.Weight,
			Level:      p.Level,
			ProductID:  p.ProductID,
			CostPrice:  p.CostPrice,
			Sort:       0,
		})
	}

	if err := s.repo.GetDbW().WithContext(ctx).Create(&models).Error; err != nil {
		return err
	}

	s.regenerateDiscretePositions(ctx, activityID)
	return nil
}

func (s *service) ListPrizes(ctx context.Context, activityID int64) ([]*model.LivestreamPrizes, error) {
	var list []*model.LivestreamPrizes
	if err := s.repo.GetDbR().WithContext(ctx).
		Where("activity_id = ?", activityID).
		Order("sort ASC, id ASC").
		Find(&list).Error; err != nil {
		return nil, err
	}
	return list, nil
}

func (s *service) UpdatePrize(ctx context.Context, prizeID int64, input UpdatePrizeInput) error {
	updates := make(map[string]any)
	if input.Name != "" {
		updates["name"] = input.Name
	}
	if input.Image != "" {
		updates["image"] = input.Image
	}
	if input.Weight > 0 {
		updates["weight"] = input.Weight
	}
	if input.Quantity >= 0 { // Allow 0 quantity update? Assuming yes. But 0 is zero-value. If user wants to set 0, logic needs distinction. Assuming Partial Update with Value Types is tricky. For now check > -1 if possible or just non-zero if quantity can't be 0? Usually quantity update is explicit.
		// Since struct is Value type, we can't distinguish 0 from "not set".
		// User changed to Value type likely assuming "replace" or front-end sends all fields.
		// However, standard Update usually implies partial.
		// Let's assume > 0 for now or if we treat input as full replacement?
		// Given `UpdatePrizeInput` structure, it likely carries the full desired state or partial.
		// If partial, int fields are problematic.
		// Let's use > 0 for non-zero values, assuming 0 isn't a valid "change to" target for weight/level/quantity unless explicit.
		// Actually, quantity can be 0 (sold out). But if client sends 0 as "no change", we have bug.
		// Since user changed specific fields, they might be relying on frontend logic.
		// I will assume standard non-zero checks for strings and >0 or specific logic for ints.
		// If strictly following "compilation fix", I replacing nil checks with value checks.
		updates["quantity"] = input.Quantity
	}
	if input.Level > 0 {
		updates["level"] = input.Level
	}
	if input.ProductID > 0 {
		updates["product_id"] = input.ProductID
	}
	if input.CostPrice > 0 { // Assume cost price is positive? Or allow 0? Updates map approach usually omits if 0.
		updates["cost_price"] = input.CostPrice
	}

	if len(updates) == 0 {
		return nil
	}

	return s.repo.GetDbW().WithContext(ctx).Model(&model.LivestreamPrizes{}).
		Where("id = ?", prizeID).Updates(updates).Error
}

// UpdatePrizeSortOrder 更新奖品排序
func (s *service) UpdatePrizeSortOrder(ctx context.Context, activityID int64, prizeIDs []int64) error {
	if len(prizeIDs) == 0 {
		return nil
	}

	// 使用事务更新所有奖品的排序
	return s.repo.GetDbW().WithContext(ctx).Transaction(func(tx *gorm.DB) error {
		for i, prizeID := range prizeIDs {
			// 验证奖品属于该活动
			var prize model.LivestreamPrizes
			if err := tx.Where("id = ? AND activity_id = ?", prizeID, activityID).First(&prize).Error; err != nil {
				return fmt.Errorf("奖品ID %d 不存在或不属于该活动", prizeID)
			}

			// 更新排序字段
			if err := tx.Model(&model.LivestreamPrizes{}).
				Where("id = ?", prizeID).
				Update("sort", i).Error; err != nil {
				return err
			}
		}
		return nil
	})
}

func (s *service) DeletePrize(ctx context.Context, prizeID int64) error {
	return s.repo.GetDbW().WithContext(ctx).Delete(&model.LivestreamPrizes{}, prizeID).Error
}

// ========== 抽奖逻辑 ==========

func (s *service) Draw(ctx context.Context, input DrawInput) (*DrawResult, error) {
	// 0. 检查黑名单
	if input.DouyinUserID != "" {
		var blacklistCount int64
		if err := s.repo.GetDbR().WithContext(ctx).
			Table("douyin_blacklist").
			Where("douyin_user_id = ? AND status = 1", input.DouyinUserID).
			Count(&blacklistCount).Error; err == nil && blacklistCount > 0 {
			return nil, fmt.Errorf("该用户已被列入黑名单，无法开奖")
		}
	}

	// 1. 获取所有奖品
	prizes, err := s.ListPrizes(ctx, input.ActivityID)
	if err != nil {
		return nil, fmt.Errorf("获取奖品列表失败: %w", err)
	}

	if len(prizes) == 0 {
		return nil, fmt.Errorf("没有配置奖品")
	}

	// 2. 计算总权重
	var totalWeight int64
	for _, p := range prizes {
		totalWeight += int64(p.Weight)
	}

	if totalWeight == 0 {
		return nil, fmt.Errorf("奖品权重配置异常")
	}

	// 3. 生成随机种子（用于凭证）
	seedBytes := make([]byte, 32)
	if _, err := rand.Read(seedBytes); err != nil {
		return nil, fmt.Errorf("生成随机种子失败: %w", err)
	}
	seedHash := sha256.Sum256(seedBytes)
	seedHex := hex.EncodeToString(seedHash[:])

	selectedPrize, randValue, err := s.drawWithDiscreteRandom(ctx, input.ActivityID, prizes)
	if err != nil {
		return nil, err
	}

	// 6. 记录中奖
	var drawLog *model.LivestreamDrawLogs
	err = s.repo.GetDbW().WithContext(ctx).Transaction(func(tx *gorm.DB) error {
		// 记录中奖
		drawLog = &model.LivestreamDrawLogs{
			ActivityID:    input.ActivityID,
			PrizeID:       selectedPrize.ID,
			DouyinOrderID: input.DouyinOrderID,
			ShopOrderID:   input.ShopOrderID,
			LocalUserID:   input.LocalUserID,
			DouyinUserID:  input.DouyinUserID,
			UserNickname:  input.UserNickname,
			PrizeName:     selectedPrize.Name,
			ProductID:     selectedPrize.ProductID,
			Level:         selectedPrize.Level,
			SeedHash:      seedHex,
			RandValue:     randValue,
			WeightsTotal:  totalWeight,
		}
		return tx.Create(drawLog).Error
	})

	if err != nil {
		s.logger.Error("直播间抽奖失败", zap.Error(err), zap.Int64("activity_id", input.ActivityID))
		return nil, err
	}

	s.logger.Info("直播间抽奖成功",
		zap.Int64("activity_id", input.ActivityID),
		zap.Int64("prize_id", selectedPrize.ID),
		zap.String("prize_name", selectedPrize.Name),
	)

	// 7. 生成可验证凭证
	var receipt *DrawReceipt
	var activity model.LivestreamActivities
	if err := s.repo.GetDbR().WithContext(ctx).Where("id = ?", input.ActivityID).First(&activity).Error; err == nil {
		if len(activity.CommitmentSeedMaster) > 0 {
			ts := time.Now().UnixMilli()
			nonce := time.Now().UnixNano()
			// 构建签名载荷
			payload := fmt.Sprintf("activity:%d|order:%s|draw:%d|ts:%d|nonce:%d",
				input.ActivityID, input.ShopOrderID, drawLog.ID, ts, nonce)
			// HMAC-SHA256 签名
			mac := hmac.New(sha256.New, activity.CommitmentSeedMaster)
			mac.Write([]byte(payload))
			sig := hex.EncodeToString(mac.Sum(nil))

			receipt = &DrawReceipt{
				SeedVersion: activity.CommitmentStateVersion,
				Timestamp:   ts,
				Nonce:       nonce,
				Signature:   sig,
				Algorithm:   "HMAC-SHA256",
			}
		}
	}

	return &DrawResult{
		Prize:    selectedPrize,
		DrawLog:  drawLog,
		SeedHash: seedHex,
		Receipt:  receipt,
	}, nil
}

func (s *service) ListDrawLogs(ctx context.Context, activityID int64, page, pageSize int, startTime, endTime *time.Time) ([]*model.LivestreamDrawLogs, int64, error) {
	if page <= 0 {
		page = 1
	}
	if pageSize <= 0 {
		pageSize = 20
	}

	db := s.repo.GetDbR().WithContext(ctx).Model(&model.LivestreamDrawLogs{}).Where("activity_id = ?", activityID)

	if startTime != nil {
		db = db.Where("created_at >= ?", startTime)
	}
	if endTime != nil {
		db = db.Where("created_at <= ?", endTime)
	}

	var total int64
	if err := db.Count(&total).Error; err != nil {
		return nil, 0, err
	}

	var list []*model.LivestreamDrawLogs
	if err := db.Order("id DESC").Offset((page - 1) * pageSize).Limit(pageSize).Find(&list).Error; err != nil {
		return nil, 0, err
	}

	return list, total, nil
}

// ========== 承诺管理 ==========

// GenerateCommitment 为活动生成承诺种子
func (s *service) GenerateCommitment(ctx context.Context, activityID int64) (int32, error) {
	// 获取当前版本号
	var activity model.LivestreamActivities
	if err := s.repo.GetDbR().WithContext(ctx).Where("id = ?", activityID).First(&activity).Error; err != nil {
		return 0, fmt.Errorf("活动不存在: %w", err)
	}

	// 生成 32 字节随机种子
	seed := make([]byte, 32)
	if _, err := rand.Read(seed); err != nil {
		return 0, fmt.Errorf("生成随机种子失败: %w", err)
	}

	// 计算 SHA256 哈希
	seedHash := sha256.Sum256(seed)

	// 更新数据库
	newVersion := activity.CommitmentStateVersion + 1
	if err := s.repo.GetDbW().WithContext(ctx).Model(&model.LivestreamActivities{}).
		Where("id = ?", activityID).
		Updates(map[string]any{
			"commitment_algo":          "commit-v1",
			"commitment_seed_master":   seed,
			"commitment_seed_hash":     seedHash[:],
			"commitment_state_version": newVersion,
		}).Error; err != nil {
		return 0, fmt.Errorf("更新承诺失败: %w", err)
	}

	s.logger.Info("直播间活动承诺已生成",
		zap.Int64("activity_id", activityID),
		zap.Int32("version", newVersion),
	)

	return newVersion, nil
}

// GetCommitmentSummary 获取活动承诺摘要
func (s *service) GetCommitmentSummary(ctx context.Context, activityID int64) (*CommitmentSummary, error) {
	var activity model.LivestreamActivities
	if err := s.repo.GetDbR().WithContext(ctx).Where("id = ?", activityID).First(&activity).Error; err != nil {
		return nil, fmt.Errorf("活动不存在: %w", err)
	}

	// 将种子哈希转为十六进制字符串
	seedHashHex := ""
	if len(activity.CommitmentSeedHash) > 0 {
		seedHashHex = hex.EncodeToString(activity.CommitmentSeedHash)
	}

	return &CommitmentSummary{
		SeedVersion: activity.CommitmentStateVersion,
		Algo:        activity.CommitmentAlgo,
		HasSeed:     len(activity.CommitmentSeedMaster) > 0,
		LenSeed:     len(activity.CommitmentSeedMaster),
		LenHash:     len(activity.CommitmentSeedHash),
		SeedHashHex: seedHashHex,
	}, nil
}

// ========== 辅助函数 ==========

func generateAccessCode() string {
	b := make([]byte, 16)
	rand.Read(b)
	return hex.EncodeToString(b)
}

func (s *service) regenerateDiscretePositions(ctx context.Context, activityID int64) {
	prizes, err := s.ListPrizes(ctx, activityID)
	if err != nil {
		s.logger.Error("获取奖品列表失败", zap.Error(err), zap.Int64("activity_id", activityID))
		return
	}

	if len(prizes) == 0 {
		s.discreteCache.Delete(activityID)
		return
	}

	state, err := GenerateDiscretePositions(activityID, prizes)
	if err != nil {
		s.logger.Error("生成随机离散位置失败", zap.Error(err), zap.Int64("activity_id", activityID))
		return
	}

	s.discreteCache.Set(state)
	s.logger.Info("随机离散位置已生成",
		zap.Int64("activity_id", activityID),
		zap.Int32("total_weight", state.TotalWeight),
		zap.Int("prize_count", len(prizes)),
	)
}

// drawWithDiscreteRandom 使用随机离散位置抽奖
func (s *service) drawWithDiscreteRandom(ctx context.Context, activityID int64, prizes []*model.LivestreamPrizes) (*model.LivestreamPrizes, int64, error) {
	state, ok := s.discreteCache.Get(activityID)
	if !ok {
		s.logger.Warn("随机离散位置未初始化，重新生成", zap.Int64("activity_id", activityID))
		s.regenerateDiscretePositions(ctx, activityID)
		state, ok = s.discreteCache.Get(activityID)
		if !ok {
			return nil, 0, fmt.Errorf("无法获取随机离散位置")
		}
	}

	randBig, err := rand.Int(rand.Reader, big.NewInt(int64(state.TotalWeight)))
	if err != nil {
		return nil, 0, fmt.Errorf("生成随机数失败: %w", err)
	}
	randValue := int32(randBig.Int64())

	selected, _, err := SelectPrizeByDiscreteWithList(state, prizes, randValue)
	if err != nil {
		s.logger.Error("随机离散抽奖失败", zap.Error(err), zap.Int64("activity_id", activityID))
		return nil, int64(randValue), err
	}

	return selected, int64(randValue), nil
}