fix: pg partitions timestamp parser (#20)

Author: lucasepe

internal/pg/manager.go

@@ -4,8 +4,8 @@ import (
 	"context"
 	"fmt"
 	"log/slog"
+	"regexp"
 	"sort"
-	"strings"
 	"time"
 
 	"github.com/jackc/pgx/v5"
@@ -155,30 +155,26 @@ func (pm *PartitionManager) listPartitions(ctx context.Context) ([]partitionInfo
 }
 
 func parsePartitionBound(bound string) (time.Time, time.Time, error) {
-
-	const layout = "2006-01-02"
-
-	// Estraggo le date
-	var from, to string
-	_, err := fmt.Sscanf(
-		bound,
-		"FOR VALUES FROM ('%s') TO ('%s')",
-		&from,
-		&to,
+	re, err := regexp.Compile(
+		`FOR VALUES FROM \('([^']+)'\) TO \('([^']+)'\)`,
 	)
 	if err != nil {
-		return time.Time{}, time.Time{}, err
+		return time.Time{}, time.Time{}, fmt.Errorf("cannot compile partiton bound regex: %w", err)
+	}
+
+	matches := re.FindStringSubmatch(bound)
+	if len(matches) != 3 {
+		return time.Time{}, time.Time{}, fmt.Errorf("cannot parse bound: %s", bound)
 	}
 
-	from = strings.TrimSuffix(from, "')")
-	to = strings.TrimSuffix(to, "')")
+	const layout = "2006-01-02 15:04:05-07"
 
-	start, err := time.Parse(layout, from)
+	start, err := time.Parse(layout, matches[1])
 	if err != nil {
 		return time.Time{}, time.Time{}, err
 	}
 
-	end, err := time.Parse(layout, to)
+	end, err := time.Parse(layout, matches[2])
 	if err != nil {
 		return time.Time{}, time.Time{}, err
 	}

internal/pg/manager_test.go

@@ -0,0 +1,80 @@
+package pg
+
+import (
+	"testing"
+	"time"
+)
+
+func TestParsePartitionBound(t *testing.T) {
+	tests := []struct {
+		name        string
+		input       string
+		wantStart   time.Time
+		wantEnd     time.Time
+		expectError bool
+	}{
+		{
+			name:  "valid postgres UTC bound",
+			input: "FOR VALUES FROM ('2026-02-17 00:00:00+00') TO ('2026-02-18 00:00:00+00')",
+			wantStart: time.Date(2026, 2, 17, 0, 0, 0, 0,
+				time.FixedZone("UTC", 0)),
+			wantEnd: time.Date(2026, 2, 18, 0, 0, 0, 0,
+				time.FixedZone("UTC", 0)),
+			expectError: false,
+		},
+		{
+			name:  "valid non-UTC offset",
+			input: "FOR VALUES FROM ('2026-02-17 00:00:00+02') TO ('2026-02-18 00:00:00+02')",
+			wantStart: time.Date(2026, 2, 17, 0, 0, 0, 0,
+				time.FixedZone("", 2*3600)),
+			wantEnd: time.Date(2026, 2, 18, 0, 0, 0, 0,
+				time.FixedZone("", 2*3600)),
+			expectError: false,
+		},
+		{
+			name:        "invalid format string",
+			input:       "INVALID STRING",
+			expectError: true,
+		},
+		{
+			name:        "missing TO section",
+			input:       "FOR VALUES FROM ('2026-02-17 00:00:00+00')",
+			expectError: true,
+		},
+		{
+			name:        "invalid timestamp",
+			input:       "FOR VALUES FROM ('2026-02-17') TO ('2026-02-18')",
+			expectError: true,
+		},
+		{
+			name:        "postgres with timezone minutes",
+			input:       "FOR VALUES FROM ('2026-02-17 00:00:00+02:00') TO ('2026-02-18 00:00:00+02:00')",
+			expectError: true, // attualmente non supportato dal layout
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			start, end, err := parsePartitionBound(tt.input)
+
+			if tt.expectError {
+				if err == nil {
+					t.Fatalf("expected error but got nil")
+				}
+				return
+			}
+
+			if err != nil {
+				t.Fatalf("unexpected error: %v", err)
+			}
+
+			if !start.Equal(tt.wantStart) {
+				t.Errorf("start mismatch\n got:  %v\n want: %v", start, tt.wantStart)
+			}
+
+			if !end.Equal(tt.wantEnd) {
+				t.Errorf("end mismatch\n got:  %v\n want: %v", end, tt.wantEnd)
+			}
+		})
+	}
+}