/**
 * Simplified elevation/ azimuth calculation
 */
export function calculateSunPosition(
    utcHours: number,
    date: Date,
    latitude: number,
    longitude: number,
): { elevation: number; azimuth: number } {
    const toRad = (deg: number) => (deg * Math.PI) / 180;
    const toDeg = (rad: number) => (rad * 180) / Math.PI;
    const dayOfYear = calculateDayOfYear(date);

    const declination = toRad(-23.45 * Math.cos(toRad((360 / 365) * (dayOfYear + 10))));

    const hourAngle = toRad((utcHours - 12) * 15 + longitude);

    const lat = toRad(latitude);

    const sinElev = Math.sin(lat) * Math.sin(declination) + Math.cos(lat) * Math.cos(declination) * Math.cos(hourAngle);
    const elevation = toDeg(Math.asin(sinElev));

    const cosAz =
        (Math.sin(declination) - Math.sin(toRad(elevation)) * Math.sin(lat)) /
        (Math.cos(toRad(elevation)) * Math.cos(lat));
    let azimuth = toDeg(Math.acos(Math.max(-1, Math.min(1, cosAz))));
    if (Math.sin(hourAngle) > 0) azimuth = 360 - azimuth;

    return {
        elevation: Math.round(elevation * 10) / 10,
        azimuth: Math.round(azimuth * 10) / 10,
    };
}

function calculateDayOfYear(date: Date): number {
    const start = new Date(date.getFullYear(), 0, 0);
    const diff = date.getTime() - start.getTime();
    return Math.floor(diff / 86400000);
}