openmeteo: refactored the OpenMeteo source files to relocate normalization logic to internal/normalizers.

internal/normalizers/openmeteo/common.go

@@ -0,0 +1,40 @@
+// FILE: ./internal/normalizers/openmeteo/common.go
+package openmeteo
+
+import (
+	"fmt"
+	"strings"
+	"time"
+)
+
+// parseOpenMeteoTime parses Open-Meteo timestamps.
+//
+// Open-Meteo commonly returns "YYYY-MM-DDTHH:MM" (no timezone suffix) when timezone
+// is provided separately. When a timezone suffix is present (RFC3339), we accept it too.
+//
+// This is provider-specific because it relies on Open-Meteo's timezone and offset fields.
+func parseOpenMeteoTime(s string, tz string, utcOffsetSeconds int) (time.Time, error) {
+	s = strings.TrimSpace(s)
+	if s == "" {
+		return time.Time{}, fmt.Errorf("empty time")
+	}
+
+	// If the server returned an RFC3339 timestamp with timezone, treat it as authoritative.
+	if t, err := time.Parse(time.RFC3339, s); err == nil {
+		return t, nil
+	}
+
+	// Typical Open-Meteo format: "2006-01-02T15:04"
+	const layout = "2006-01-02T15:04"
+
+	// Best effort: try to load the timezone as an IANA name.
+	if tz != "" {
+		if loc, err := time.LoadLocation(tz); err == nil {
+			return time.ParseInLocation(layout, s, loc)
+		}
+	}
+
+	// Fallback: use a fixed zone from the offset seconds.
+	loc := time.FixedZone("open-meteo", utcOffsetSeconds)
+	return time.ParseInLocation(layout, s, loc)
+}