using System;

using UnityEngine;

namespace Framework.Geometry.Lines {

  /// <summary>2D infinite line</summary>
  public struct Line2 {

    /// <summary>A default line</summary>
    public static readonly Line2 Default = new Line2(Vector2.zero, Vector2.right);

    /// <summary>Offset of the line from the coordinate system's center</summary>
    public Vector2 Offset;
    /// <summary>Direction along which the line runs</summary>
    public Vector2 Direction;

    /// <summary>Initializes a new line</summary>
    /// <param name="offsetX">
    ///   X coordinate of the line's offset from the coordinate system's center
    /// </param>
    /// <param name="offsetY">
    ///   Y coordinate of the line's offset from the coordinate system's center
    /// </param>
    /// <param name="directionX">
    ///   X coordinate of the direction along which the line runs
    /// </param>
    /// <param name="directionY">
    ///   Y coordinate of the direction along which the line runs
    /// </param>
    public Line2(float offsetX, float offsetY, float directionX, float directionY) {
      this.Offset = new Vector2(offsetX, offsetY);
      this.Direction = new Vector2(directionX, directionY);
    }

    /// <summary>Initializes a new line</summary>
    /// <param name="offset">Offset of the line from the coordinate system's center</param>
    /// <param name="direction">Direction along which the line runs</param>
    public Line2(Vector2 offset, Vector2 direction) {
      this.Offset = offset;
      this.Direction = direction;
    }

    /// <summary>
    ///   Determines whether this instance is identical to another instance
    /// </summary>
    /// <param name="otherObject">Other instance of compare against</param>
    /// <returns>True if both instances are identical</returns>
    public override bool Equals(object otherObject) {
      if(!(otherObject is Line2)) {
        return false;
      }

      Line2 other = (Line2)otherObject;
      return (
        (this.Offset == other.Offset) &&
        (this.Direction == other.Direction)
      );
    }

    /// <summary>Returns a hash code for the instance</summary>
    /// <returns>The instance's hash code</returns>
    public override int GetHashCode() {
      return this.Offset.GetHashCode() ^ this.Direction.GetHashCode();
    }

  }

} // namespace Framework.Geometry.Lines