package database

import (
	"context"
	"database/sql"
)

// StationCoord holds a station_id with geographic coordinates.
type StationCoord struct {
	StationID string
	Lat       float64
	Lon       float64
}

// ListWH65LPStationsWithLatLon returns WH65LP stations that have non-null and non-zero lat/lon.
func ListWH65LPStationsWithLatLon(ctx context.Context, db *sql.DB) ([]StationCoord, error) {
	const q = `
        SELECT station_id, latitude, longitude
        FROM stations
        WHERE device_type = 'WH65LP'
          AND latitude IS NOT NULL AND longitude IS NOT NULL
          AND latitude <> 0 AND longitude <> 0
        ORDER BY station_id`
	rows, err := db.QueryContext(ctx, q)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var out []StationCoord
	for rows.Next() {
		var s StationCoord
		if err := rows.Scan(&s.StationID, &s.Lat, &s.Lon); err != nil {
			continue
		}
		out = append(out, s)
	}
	return out, nil
}