package wheel

import (
	"context"
	"log/slog"
	"strings"
	"time"

	"google.golang.org/grpc"
	walletv1 "hyapp.local/api/proto/wallet/v1"
	"hyapp/pkg/appcode"
	"hyapp/pkg/logx"
	"hyapp/pkg/xerr"
	domain "hyapp/services/activity-service/internal/domain/wheel"
)

type Repository interface {
	PublishWheelRuleConfig(ctx context.Context, config domain.RuleConfig, nowMS int64) (domain.RuleConfig, error)
	GetWheelRuleConfig(ctx context.Context, wheelID string) (domain.RuleConfig, bool, error)
	ExecuteWheelDraw(ctx context.Context, cmd domain.DrawCommand, nowMS int64) (domain.DrawResult, error)
	ListWheelDraws(ctx context.Context, query domain.DrawQuery) ([]domain.DrawResult, int64, error)
	GetWheelDrawSummary(ctx context.Context, query domain.DrawQuery) (domain.DrawSummary, error)
	MarkWheelDrawsGranted(ctx context.Context, appCode string, drawIDs []string, transactionID string, nowMS int64) error
}

type WalletClient interface {
	CreditWheelReward(ctx context.Context, req *walletv1.CreditWheelRewardRequest, opts ...grpc.CallOption) (*walletv1.CreditWheelRewardResponse, error)
}

type Service struct {
	repository Repository
	wallet     WalletClient
	now        func() time.Time
}

type Option func(*Service)

func WithWallet(client WalletClient) Option {
	return func(s *Service) {
		s.wallet = client
	}
}

func New(repository Repository, options ...Option) *Service {
	service := &Service{repository: repository, now: time.Now}
	for _, option := range options {
		if option != nil {
			option(service)
		}
	}
	return service
}

func (s *Service) SetClock(now func() time.Time) {
	if now != nil {
		s.now = now
	}
}

func (s *Service) Draw(ctx context.Context, cmd domain.DrawCommand) (domain.DrawResult, error) {
	if err := s.requireRepository(); err != nil {
		return domain.DrawResult{}, err
	}
	cmd.CommandID = strings.TrimSpace(cmd.CommandID)
	cmd.WheelID = NormalizeWheelID(cmd.WheelID)
	cmd.DeviceID = strings.TrimSpace(cmd.DeviceID)
	if cmd.DrawCount <= 0 {
		cmd.DrawCount = 1
	}
	if cmd.CommandID == "" || cmd.WheelID == "" || cmd.UserID <= 0 || cmd.DeviceID == "" || cmd.CoinSpent <= 0 {
		return domain.DrawResult{}, xerr.New(xerr.InvalidArgument, "wheel draw command is incomplete")
	}
	if cmd.PaidAtMS <= 0 {
		// paid_at_ms 来自钱包扣费事实；缺失时使用 UTC 服务端时间，保证 RTP 窗口和审计时间不受本地时区影响。
		cmd.PaidAtMS = s.now().UTC().UnixMilli()
	}
	result, err := s.repository.ExecuteWheelDraw(ctx, cmd, s.now().UTC().UnixMilli())
	if err != nil {
		return domain.DrawResult{}, err
	}
	return s.creditCoinRewardFastPath(ctx, cmd, result), nil
}

func (s *Service) UpsertConfig(ctx context.Context, config domain.RuleConfig) (domain.RuleConfig, error) {
	if err := s.requireRepository(); err != nil {
		return domain.RuleConfig{}, err
	}
	config = NormalizeRuleConfig(config)
	if err := ValidateRuleConfig(config); err != nil {
		return domain.RuleConfig{}, err
	}
	return s.repository.PublishWheelRuleConfig(ctx, config, s.now().UTC().UnixMilli())
}

func (s *Service) GetConfig(ctx context.Context, wheelID string) (domain.RuleConfig, error) {
	if err := s.requireRepository(); err != nil {
		return domain.RuleConfig{}, err
	}
	config, exists, err := s.repository.GetWheelRuleConfig(ctx, NormalizeWheelID(wheelID))
	if err != nil {
		return domain.RuleConfig{}, err
	}
	if !exists {
		return domain.RuleConfig{}, xerr.New(xerr.NotFound, "wheel config not found")
	}
	return config, nil
}

func (s *Service) ListDraws(ctx context.Context, query domain.DrawQuery) ([]domain.DrawResult, int64, error) {
	if err := s.requireRepository(); err != nil {
		return nil, 0, err
	}
	return s.repository.ListWheelDraws(ctx, normalizeDrawQuery(query))
}

func (s *Service) GetDrawSummary(ctx context.Context, query domain.DrawQuery) (domain.DrawSummary, error) {
	if err := s.requireRepository(); err != nil {
		return domain.DrawSummary{}, err
	}
	return s.repository.GetWheelDrawSummary(ctx, normalizeDrawQuery(query))
}

func (s *Service) creditCoinRewardFastPath(ctx context.Context, cmd domain.DrawCommand, result domain.DrawResult) domain.DrawResult {
	if result.RewardType != domain.RewardTypeCoin || result.RewardCoins <= 0 || result.RewardStatus == domain.StatusGranted || len(result.DrawIDs) != 1 {
		return result
	}
	if s.wallet == nil {
		logx.Warn(ctx, "wheel_reward_wallet_not_configured", slog.String("draw_id", result.DrawID))
		return result
	}
	resp, err := s.wallet.CreditWheelReward(appcode.WithContext(ctx, appcode.FromContext(ctx)), &walletv1.CreditWheelRewardRequest{
		CommandId:       "wheel_reward:" + result.DrawID,
		AppCode:         appcode.FromContext(ctx),
		TargetUserId:    cmd.UserID,
		Amount:          result.RewardCoins,
		DrawId:          result.DrawID,
		WheelId:         result.WheelID,
		SelectedTierId:  result.SelectedTierID,
		Reason:          "wheel_reward",
		VisibleRegionId: cmd.VisibleRegionID,
	})
	if err != nil {
		// 钱包不可用不能回滚已经确认的抽奖事实；pending 记录和 outbox 保留，后续补偿 worker 可以继续处理。
		logx.Error(ctx, "wheel_reward_fast_path_failed", err, slog.String("draw_id", result.DrawID), slog.String("command_id", result.CommandID))
		return result
	}
	result.RewardStatus = domain.StatusGranted
	result.WalletTransactionID = resp.GetTransactionId()
	result.CoinBalanceAfter = resp.GetBalance().GetAvailableAmount()
	if err := s.repository.MarkWheelDrawsGranted(appcode.WithContext(context.WithoutCancel(ctx), appcode.FromContext(ctx)), appcode.FromContext(ctx), result.DrawIDs, result.WalletTransactionID, s.now().UTC().UnixMilli()); err != nil {
		logx.Error(ctx, "wheel_reward_fast_path_mark_granted_failed", err, slog.String("draw_id", result.DrawID), slog.String("wallet_transaction_id", result.WalletTransactionID))
	}
	return result
}

func normalizeDrawQuery(query domain.DrawQuery) domain.DrawQuery {
	query.WheelID = NormalizeWheelID(query.WheelID)
	query.Status = strings.TrimSpace(query.Status)
	if query.Page <= 0 {
		query.Page = 1
	}
	if query.PageSize <= 0 {
		query.PageSize = 20
	}
	if query.PageSize > 100 {
		query.PageSize = 100
	}
	return query
}

func (s *Service) requireRepository() error {
	if s == nil || s.repository == nil {
		return xerr.New(xerr.Unavailable, "wheel repository is not configured")
	}
	return nil
}