package data

import (
	"database/sql"
	"time"
)

type RadarWeather struct {
	Alias         string
	Lat           float64
	Lon           float64
	DT            time.Time
	Temperature   sql.NullFloat64
	Humidity      sql.NullFloat64
	CloudRate     sql.NullFloat64
	Visibility    sql.NullFloat64
	DSWRF         sql.NullFloat64
	WindSpeed     sql.NullFloat64
	WindDirection sql.NullFloat64
	Pressure      sql.NullFloat64
}

// RadarWeatherNearest returns the nearest radar_weather row to (lat,lon) around dt within a window.
// It orders by absolute time difference then squared distance.
func RadarWeatherNearest(lat, lon float64, dt time.Time, window time.Duration) (*RadarWeather, error) {
	from := dt.Add(-window)
	to := dt.Add(window)
	const q = `
        SELECT alias, lat, lon, dt, temperature, humidity, cloudrate, visibility, dswrf,
               wind_speed, wind_direction, pressure
        FROM radar_weather
        WHERE dt BETWEEN $1 AND $2
        ORDER BY ABS(EXTRACT(EPOCH FROM (dt - $3))) ASC,
                 ((lat - $4)*(lat - $4) + (lon - $5)*(lon - $5)) ASC
        LIMIT 1`
	row := DB().QueryRow(q, from, to, dt, lat, lon)
	var rw RadarWeather
	if err := row.Scan(&rw.Alias, &rw.Lat, &rw.Lon, &rw.DT, &rw.Temperature, &rw.Humidity, &rw.CloudRate, &rw.Visibility, &rw.DSWRF, &rw.WindSpeed, &rw.WindDirection, &rw.Pressure); err != nil {
		if err == sql.ErrNoRows {
			return nil, nil
		}
		return nil, err
	}
	return &rw, nil
}