// 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)
}