// FILE: ./internal/normalizers/openweather/common.go
package openweather

import (
	"fmt"
	"strings"
)

// This file holds provider-specific helpers that are shared across multiple
// OpenWeather normalizers (observations today; forecasts/alerts later).
// Keeping these out of observation.go helps preserve the "one normalizer per file"
// convention while avoiding duplication.

// primaryCondition returns the "primary" weather condition from OpenWeather's
// weather array. Per OpenWeather conventions, element [0] is treated as primary.
func primaryCondition(list []owmWeather) (id int, desc string, icon string) {
	if len(list) == 0 {
		return 0, "", ""
	}
	w := list[0]
	return w.ID, strings.TrimSpace(w.Description), strings.TrimSpace(w.Icon)
}

// inferIsDay determines day/night using the best available upstream signals.
//
// Priority:
//  1. The OpenWeather icon suffix ("d" / "n") when present.
//  2. Sunrise/sunset bounds (unix seconds), if provided.
//  3. Unknown (nil) when no reliable signal is present.
func inferIsDay(icon string, dt, sunrise, sunset int64) *bool {
	// Prefer icon suffix.
	icon = strings.TrimSpace(icon)
	if icon != "" {
		last := icon[len(icon)-1]
		switch last {
		case 'd':
			v := true
			return &v
		case 'n':
			v := false
			return &v
		}
	}

	// Fall back to sunrise/sunset bounds if provided.
	if dt > 0 && sunrise > 0 && sunset > 0 {
		v := dt >= sunrise && dt < sunset
		return &v
	}

	return nil
}

// openWeatherIconURL builds the standard OpenWeather icon URL for the given icon code.
func openWeatherIconURL(icon string) string {
	icon = strings.TrimSpace(icon)
	if icon == "" {
		return ""
	}
	return fmt.Sprintf("https://openweathermap.org/img/wn/%s@2x.png", icon)
}

// openWeatherStationID returns a stable station identifier for the given response.
// Prefer the OpenWeather city ID when present; otherwise, fall back to coordinates.
func openWeatherStationID(parsed owmResponse) string {
	if parsed.ID != 0 {
		return fmt.Sprintf("OPENWEATHER(%d)", parsed.ID)
	}
	// Fallback: synthesize from coordinates.
	return fmt.Sprintf("OPENWEATHER(%.5f,%.5f)", parsed.Coord.Lat, parsed.Coord.Lon)
}