code cleanup

internal/tasks/inventoryHelpers.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"database/sql"
 	"fmt"
-	"strconv"
 	"strings"
 	"time"
 
@@ -42,51 +41,62 @@ func boolStringFromInterface(value interface{}) string {
 	}
 }
 
-// latestHourlySnapshotBefore finds the most recent hourly snapshot table prior to the given time.
+// latestHourlySnapshotBefore finds the most recent hourly snapshot table prior to the given time, skipping empty tables.
 func latestHourlySnapshotBefore(ctx context.Context, dbConn *sqlx.DB, cutoff time.Time) (string, error) {
-	driver := strings.ToLower(dbConn.DriverName())
-	var rows *sqlx.Rows
-	var err error
-	switch driver {
-	case "sqlite":
-		rows, err = dbConn.QueryxContext(ctx, `
-SELECT name FROM sqlite_master
-WHERE type = 'table' AND name LIKE 'inventory_hourly_%'
-`)
-	case "pgx", "postgres":
-		rows, err = dbConn.QueryxContext(ctx, `
-SELECT tablename FROM pg_catalog.pg_tables
-WHERE schemaname = 'public' AND tablename LIKE 'inventory_hourly_%'
-`)
-	default:
-		return "", fmt.Errorf("unsupported driver for snapshot lookup: %s", driver)
-	}
+	rows, err := dbConn.QueryxContext(ctx, `
+SELECT table_name, snapshot_time
+FROM snapshot_registry
+WHERE snapshot_type = 'hourly' AND snapshot_time < ?
+ORDER BY snapshot_time DESC
+`, cutoff.Unix())
 	if err != nil {
 		return "", err
 	}
 	defer rows.Close()
 
-	var latest string
-	var latestTime int64
 	for rows.Next() {
 		var name string
-		if scanErr := rows.Scan(&name); scanErr != nil {
+		var ts int64
+		if scanErr := rows.Scan(&name, &ts); scanErr != nil {
 			continue
 		}
-		if !strings.HasPrefix(name, "inventory_hourly_") {
+		if err := db.ValidateTableName(name); err != nil {
 			continue
 		}
-		suffix := strings.TrimPrefix(name, "inventory_hourly_")
-		epoch, parseErr := strconv.ParseInt(suffix, 10, 64)
-		if parseErr != nil {
+		hasRows, err := db.TableHasRows(ctx, dbConn, name)
+		if err != nil {
 			continue
 		}
-		if epoch < cutoff.Unix() && epoch > latestTime {
-			latestTime = epoch
-			latest = name
+		if hasRows {
+			return name, nil
 		}
 	}
-	return latest, nil
+	return "", nil
+}
+
+// HasSnapshotGap reports whether the gap between prev and curr exceeds 2x the expected interval.
+func HasSnapshotGap(prevUnix, currUnix int64, expectedSeconds int64) bool {
+	if prevUnix == 0 || currUnix == 0 || expectedSeconds <= 0 {
+		return false
+	}
+	return currUnix-prevUnix > expectedSeconds*2
+}
+
+// querySnapshotRows builds a SELECT with proper rebind for the given table/columns/where.
+func querySnapshotRows(ctx context.Context, dbConn *sqlx.DB, table string, columns []string, where string, args ...interface{}) (*sqlx.Rows, error) {
+	if err := db.ValidateTableName(table); err != nil {
+		return nil, err
+	}
+	colExpr := "*"
+	if len(columns) > 0 {
+		colExpr = `"` + strings.Join(columns, `","`) + `"`
+	}
+	query := fmt.Sprintf(`SELECT %s FROM %s`, colExpr, table)
+	if strings.TrimSpace(where) != "" {
+		query = fmt.Sprintf(`%s WHERE %s`, query, where)
+	}
+	query = sqlx.Rebind(sqlx.BindType(dbConn.DriverName()), query)
+	return dbConn.QueryxContext(ctx, query, args...)
 }
 
 // markMissingFromPrevious marks VMs that were present in the previous snapshot but missing now.
@@ -98,9 +108,6 @@ func (c *CronTask) markMissingFromPrevious(ctx context.Context, dbConn *sqlx.DB,
 		return 0
 	}
 
-	query := fmt.Sprintf(`SELECT "VmId","VmUuid","Name","Cluster","Datacenter","DeletionTime" FROM %s WHERE "Vcenter" = ?`, prevTable)
-	query = sqlx.Rebind(sqlx.BindType(dbConn.DriverName()), query)
-
 	type prevRow struct {
 		VmId         sql.NullString `db:"VmId"`
 		VmUuid       sql.NullString `db:"VmUuid"`
@@ -110,7 +117,7 @@ func (c *CronTask) markMissingFromPrevious(ctx context.Context, dbConn *sqlx.DB,
 		DeletionTime sql.NullInt64  `db:"DeletionTime"`
 	}
 
-	rows, err := dbConn.QueryxContext(ctx, query, vcenter)
+	rows, err := querySnapshotRows(ctx, dbConn, prevTable, []string{"VmId", "VmUuid", "Name", "Cluster", "Datacenter", "DeletionTime"}, `"Vcenter" = ?`, vcenter)
 	if err != nil {
 		c.Logger.Warn("failed to read previous snapshot for deletion detection", "error", err, "table", prevTable, "vcenter", vcenter)
 		return 0