/// <summary>
/// <para>Line is defined by starting point and ending point on 2D dimension.</para>
/// <para>Point on 2D landscape.</para>
/// <para>author Roman Kushnarenko (sromku@gmail.com)</para>
/// <para>C# version https://github.com/BergWerkGIS </para>
/// </summary>
public class Line {

	private Point _start;
	private Point _end;
	private double _a = double.NaN;
	private double _b = double.NaN;
	private bool _vertical = false;

	public Line(Point start, Point end) {
		_start = start;
		_end = end;

		if (_end.x - _start.x != 0) {
			_a = ((_end.y - _start.y) / (_end.x - _start.x));
			_b = _start.y - _a * _start.x;
		} else {
			_vertical = true;
		}
	}


	/// <summary>
	/// Indicate whereas the point lays on the line.
	/// </summary>
	/// <param name="point">The point to check</param>
	/// <returns><code>True</code> if the point lays on the line, otherwise return <code>False</code></returns>
	public bool isInside(Point point) {
		double maxX = _start.x > _end.x ? _start.x : _end.x;
		double minX = _start.x < _end.x ? _start.x : _end.x;
		double maxY = _start.y > _end.y ? _start.y : _end.y;
		double minY = _start.y < _end.y ? _start.y : _end.y;

		if ((point.x >= minX && point.x <= maxX) && (point.y >= minY && point.y <= maxY)) {
			return true;
		}
		return false;
	}


	/// <summary>
	/// <para>Indicate whereas the line is vertical.</para>
	/// <para>For example, line like x=1 is vertical, in other words parallel to axis Y.</para>
	/// <para>In this case the A is (+/-)infinite.</para>
	/// </summary>
	/// <returns></returns>
	public bool isVertical() {
		return _vertical;
	}


	/// <summary>
	/// y = <b>A</b>x + B
	/// </summary>
	/// <returns>The <b>A</b></returns>
	public double getA() {
		return _a;
	}


	/// <summary>
	/// y = Ax + <b>B</b>
	/// </summary>
	/// <returns> The <b>B</b></returns>
	public double getB() {
		return _b;
	}


	/// <summary>
	/// Get start point.
	/// </summary>
	/// <returns>The start point.</returns>
	public Point getStart() {
		return _start;
	}


	/// <summary>
	/// Get end point.
	/// </summary>
	/// <returns>The end point.</returns>
	public Point getEnd() {
		return _end;
	}

	public override string ToString() {
		return $"{_start}-{_end}";
	}


}