Hanlde trading212 inconsistent date formats (#31)

Reviewed-on: #31
Co-authored-by: Natercio Moniz <[email protected]>

internal/trading212/record.go

@@ -114,7 +114,7 @@ func (rr RecordReader) ReadRecord(ctx context.Context) (internal.Record, error)
 			return Record{}, fmt.Errorf("parse record price: %w", err)
 		}
 
-		ts, err := time.Parse(time.DateTime, raw[1])
+		ts, err := parseTimestamp(raw[1])
 		if err != nil {
 			return Record{}, fmt.Errorf("parse record timestamp: %w", err)
 		}
@@ -225,6 +225,30 @@ func parseOptionalDecimal(s string) (decimal.Decimal, error) {
 	return parseDecimal(s)
 }
 
+// parseTimestamp parses a Trading212 timestamp string. Trading212 has shipped
+// rows both without a timezone (treated here as UTC) and with an explicit
+// numeric offset (e.g. "+00:00", "-05:00", "+01:00") or a "Z" UTC marker.
+// The layouts are tried in order; the first match wins.
+func parseTimestamp(s string) (time.Time, error) {
+	layouts := [3]string{
+		"2006-01-02 15:04:05-07:00", // numeric offset
+		time.DateTime,               // "2006-01-02 15:04:05"
+		"2006-01-02 15:04:05Z",      // explicit UTC marker
+	}
+
+	var (
+		lastErr error
+		ts      time.Time
+	)
+	for _, layout := range layouts {
+		ts, lastErr = time.Parse(layout, s)
+		if lastErr == nil {
+			return ts, nil
+		}
+	}
+	return time.Time{}, lastErr
+}
+
 type splitRecord struct {
 	Record