feat: user buy media

backend/modules/medias/service.go

@@ -11,6 +11,7 @@ import (
 
 	"backend/database/models/qvyun/public/model"
 	"backend/database/models/qvyun/public/table"
+	"backend/pkg/errorx"
 	"backend/pkg/media_store"
 	"backend/pkg/path"
 	"backend/pkg/pg"
@@ -314,3 +315,94 @@ func (svc *Service) GetM3U8(ctx context.Context, tenantId int64, types pg.MediaT
 func (svc *Service) GetSegmentPath(ctx context.Context, t pg.MediaType, hash string, segment int64) string {
 	return filepath.Join(svc.storageConfig.Path, hash, t.String(), fmt.Sprintf("%d.ts", segment))
 }
+
+func (svc *Service) Checkout(ctx context.Context, tenantId, userId, mediaId int64) error {
+	log := svc.log.WithField("method", "Checkout")
+
+	bought, err := svc.HasUserBought(ctx, tenantId, userId, mediaId)
+	if err != nil {
+		return errors.Wrap(err, "check user bought")
+	}
+
+	if bought {
+		return nil
+	}
+
+	media, err := svc.GetMediaByID(ctx, tenantId, userId, mediaId)
+	if err != nil {
+		return errors.Wrap(err, "get media")
+	}
+
+	userBalance, err := svc.GetUserBalance(ctx, tenantId, userId)
+	if err != nil {
+		return errors.Wrap(err, "get user balance")
+	}
+
+	if userBalance < media.Price {
+		return errorx.UserBalanceNotEnough
+	}
+
+	tx, err := svc.db.Begin()
+	if err != nil {
+		return errors.Wrap(err, "begin transaction")
+	}
+	defer tx.Rollback()
+
+	tbl := table.UserMedias
+	stmt := tbl.
+		INSERT(tbl.TenantID, tbl.UserID, tbl.MediaID, tbl.Price).
+		VALUES(Int(tenantId), Int(userId), Int(mediaId), Int(media.Price))
+	log.Debug(stmt.DebugSql())
+
+	if _, err := stmt.ExecContext(ctx, tx); err != nil {
+		return errors.Wrap(err, "insert user media")
+	}
+
+	// update user balance
+	tblUserTenants := table.UsersTenants
+	stmtUserTenants := tblUserTenants.
+		UPDATE().
+		SET(
+			tblUserTenants.Balance.SET(
+				tblUserTenants.Balance.SUB(Int(media.Price)),
+			),
+		).
+		WHERE(
+			tblUserTenants.TenantID.EQ(Int(tenantId)).AND(
+				tblUserTenants.UserID.EQ(Int(userId)),
+			),
+		)
+	log.Debug(stmtUserTenants.DebugSql())
+
+	if _, err := stmtUserTenants.ExecContext(ctx, tx); err != nil {
+		return errors.Wrap(err, "update user balance")
+	}
+
+	if err := tx.Commit(); err != nil {
+		return errors.Wrap(err, "commit transaction")
+	}
+
+	return nil
+}
+
+// GetUserBalance
+func (svc *Service) GetUserBalance(ctx context.Context, tenantId, userId int64) (int64, error) {
+	log := svc.log.WithField("method", "GetUserBalance")
+
+	tbl := table.UsersTenants
+	stmt := tbl.SELECT(tbl.Balance.AS("balance")).WHERE(
+		tbl.TenantID.EQ(Int(tenantId)).AND(
+			tbl.UserID.EQ(Int(userId)),
+		),
+	)
+	log.Debug(stmt.DebugSql())
+
+	var result struct {
+		Balance int64
+	}
+	if err := stmt.QueryContext(ctx, svc.db, &result); err != nil {
+		return 0, errors.Wrap(err, "query user balance")
+	}
+
+	return result.Balance, nil
+}