package service

import (
	"context"
	"strings"
	"time"

	appErrors "github.com/topfans/backend/pkg/errors"
	"github.com/topfans/backend/pkg/logger"
	notifPb "github.com/topfans/backend/pkg/proto/notification"
	"github.com/topfans/backend/services/notificationService/repository"
	"go.uber.org/zap"
	"google.golang.org/grpc/codes"
	"gorm.io/gorm"
)

// ========== 设备注册服务 ==========
//
// UserDeviceService 处理客户端推送 token (cid) 的注册与注销。
// 调用方:gateway 通过 Dubbo RPC 转发 App 端的 RegisterDevice / UnregisterDevice。
//
// 行为约定:
//   - RegisterDevice:按 cid upsert;同 cid 已存在则更新归属/platform/version。
//   - UnregisterDevice:cid 非空时按 cid 注销;cid 为空时按 user_id 注销该用户所有设备(主动登出场景)。

// UserDeviceService 设备服务。
type UserDeviceService struct {
	db   *gorm.DB
	repo *repository.UserDeviceRepository
}

// NewUserDeviceService 创建 UserDeviceService。
func NewUserDeviceService(db *gorm.DB) *UserDeviceService {
	return &UserDeviceService{
		db:   db,
		repo: repository.NewUserDeviceRepository(db),
	}
}

// DB 返回底层 gorm.DB(供同包 NotificationService 调用查询 cids)。
func (s *UserDeviceService) DB() *gorm.DB { return s.db }

// RegisterDevice 注册/更新 cid。
func (s *UserDeviceService) RegisterDevice(
	ctx context.Context,
	userID int64,
	req *notifPb.RegisterDeviceRequest,
) (*notifPb.RegisterDeviceResponse, error) {
	if userID <= 0 {
		return nil, appErrors.NewError(codes.InvalidArgument, "user_id is required")
	}
	if req == nil || strings.TrimSpace(req.Cid) == "" {
		return nil, appErrors.NewError(codes.InvalidArgument, "cid is required")
	}

	// 平台号做白名单简单保护(后续可加更严格的枚举)
	platform := strings.ToLower(strings.TrimSpace(req.Platform))
	switch platform {
	case "ios", "android", "harmony", "":
		// 通过
	default:
		// 未知平台也允许写入,便于鸿蒙/小程序等新通道接入;只 warn
		logger.Logger.Warn("register device with unknown platform",
			zap.Int64("user_id", userID),
			zap.String("platform", platform))
	}

	d, err := s.repo.UpsertByCID(ctx, nil,
		strings.TrimSpace(req.Cid),
		userID,
		platform,
		strings.TrimSpace(req.AppVersion),
		strings.TrimSpace(req.DeviceModel),
	)
	if err != nil {
		logger.Logger.Error("RegisterDevice upsert failed",
			zap.Int64("user_id", userID),
			zap.String("cid", req.Cid),
			zap.Error(err))
		return nil, appErrors.NewError(codes.Internal, "register device failed")
	}

	logger.Logger.Info("device registered",
		zap.Int64("id", d.ID),
		zap.Int64("user_id", userID),
		zap.String("platform", d.Platform),
		zap.String("cid", d.CID))

	return &notifPb.RegisterDeviceResponse{
		Base: appErrors.FormatSuccessResponse(),
		Id:   d.ID,
	}, nil
}

// UnregisterDevice 注销 cid;cid 为空时注销 user 的所有设备。
func (s *UserDeviceService) UnregisterDevice(
	ctx context.Context,
	userID int64,
	req *notifPb.UnregisterDeviceRequest,
) (*notifPb.UnregisterDeviceResponse, error) {
	if userID <= 0 {
		return nil, appErrors.NewError(codes.InvalidArgument, "user_id is required")
	}
	if req == nil {
		return nil, appErrors.NewError(codes.InvalidArgument, "request is nil")
	}

	cid := strings.TrimSpace(req.Cid)
	var affected int64
	var err error

	if cid != "" {
		affected, err = s.repo.DeactivateByCID(ctx, nil, cid)
	} else {
		// cid 为空:注销该用户全部(批量 UPDATE)
		res := s.db.WithContext(ctx).Exec(`
			UPDATE public.user_devices
			SET active = FALSE, updated_at = $1
			WHERE user_id = $2 AND active = TRUE
		`, time.Now().UnixMilli(), userID)
		affected, err = res.RowsAffected, res.Error
	}
	if err != nil {
		logger.Logger.Error("UnregisterDevice failed",
			zap.Int64("user_id", userID),
			zap.String("cid", cid),
			zap.Error(err))
		return nil, appErrors.NewError(codes.Internal, "unregister device failed")
	}

	logger.Logger.Info("device unregistered",
		zap.Int64("user_id", userID),
		zap.String("cid", cid),
		zap.Int64("affected", affected))

	return &notifPb.UnregisterDeviceResponse{
		Base:     appErrors.FormatSuccessResponse(),
		Affected: int32(affected),
	}, nil
}

// ListActiveCIDs 获取某用户的活跃 cid 列表(供 NotificationService 推送时调用)。
func (s *UserDeviceService) ListActiveCIDs(ctx context.Context, userID int64) ([]string, error) {
	return s.repo.ListActiveCIDsByUserID(ctx, userID)
}