export type BoundingBox = {
    south: number
    north: number
    west: number
    east: number
}

export default class GeoLocation {
    public lat: number
    public lon: number

    constructor(lat: number, lon: number) {
        this.lat = lat
        this.lon = lon
    }

    public toCartesian (
        boundingBox: BoundingBox,
        xMax: number,
        yMax: number
    ): {x: number, y: number} {
        const { lat, lon } = this
        const { south, north, west, east } = boundingBox
    
        const x = ((lon - west) / (east - west)) * xMax
        const y = ((north - lat) / (north - south)) * yMax
    
        return { x, y}
    }

    public toString() {
        return `(${this.lat}, ${this.lon})`
    }

    /**
     * Gives the distance between two points on the Earth's surface using the Haversine formula.
     * The returned distance is in meters.
     */
    public haversineDistance (other: GeoLocation): number {
        const R = 6371000 // Earth's radius in meters
        const toRadians = (deg: number) => (deg * Math.PI) / 180
      
        const dLat = toRadians(other.lat - this.lat)
        const dLon = toRadians(other.lon - this.lon)
      
        const a =
          Math.sin(dLat / 2) * Math.sin(dLat / 2) +
          Math.cos(toRadians(this.lat)) * Math.cos(toRadians(other.lat)) *
          Math.sin(dLon / 2) * Math.sin(dLon / 2)
      
        const c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a))
      
        return R * c // Distance in meters
    }
        
}