using System;

using System.Collections.Generic;

using GeoJSON.Net.Geometry;

namespace GeoJSON.Net

{

internal static class PositionExtensions

{

internal static Position ToPosition(this IEnumerable<double> coordinates)

{

using (var enumerator = coordinates.GetEnumerator())

{

double lat, lng, alt;

if (!enumerator.MoveNext())

{

throw new ArgumentException("Expected 2 or 3 coordinates but got 0");

}

lng = enumerator.Current;

if (!enumerator.MoveNext())

{

throw new ArgumentException("Expected 2 or 3 coordinates but got 1");

}

lat = enumerator.Current;

if (!enumerator.MoveNext())

{

return new Position(lat, lng);

}

alt = enumerator.Current;

if (enumerator.MoveNext())

{

throw new ArgumentException("Expected 2 or 3 coordinates but got >= 4");

}

return new Position(lat, lng, alt);

}

}

}

}