using System.Drawing;
using System.Drawing.Drawing2D;

namespace Netron.Diagramming.Core {
  // ----------------------------------------------------------------------
  /// <summary>
  /// Extended <see cref="PenStyle"/> with extra properties for the design 
  /// of connections.  
  /// <remarks>Although the .Net 2.0 framework allows you to set line caps 
  /// the result is, humbly said, rather poor. The caps are not drawn 
  /// proportionally and custom caps cannot be filled resulting in a 'not 
  /// implemented' exception.  So, the only working solution (read: hack) 
  /// I found is to draw the caps with a secondary pen whose size is bigger 
  /// than the base pen with which the line is drawn. Unfortunately this 
  /// hack cannot solely be implemented in this class, you need to fix it 
  /// in the painting routines.  Hopefully a solution will be around later 
  /// on.
  /// </remarks>
  /// </summary>
  // ----------------------------------------------------------------------
  public partial class LinePenStyle : PenStyle {

    #region Fields

    // ------------------------------------------------------------------
    /// <summary>
    /// Implementation of IVersion - the current version of 
    /// LinePenStyle.
    /// </summary>
    // ------------------------------------------------------------------
    protected const double linePenStyleVersion = 1.0;

    // ------------------------------------------------------------------
    /// <summary>
    /// the custom end cap
    /// </summary>
    // ------------------------------------------------------------------
    private CustomLineCap mCustomEndCap;

    // ------------------------------------------------------------------
    /// <summary>
    /// the custom start cap
    /// </summary>
    // ------------------------------------------------------------------
    private CustomLineCap mCustomStartCap;

    // ------------------------------------------------------------------
    /// <summary>
    /// the start cap
    /// </summary>
    // ------------------------------------------------------------------
    private LineCap mStartCap = LineCap.NoAnchor;

    // ------------------------------------------------------------------
    /// <summary>
    /// the end cap
    /// </summary>
    // ------------------------------------------------------------------
    private LineCap mEndCap = LineCap.NoAnchor;

    // ------------------------------------------------------------------
    /// <summary>
    /// the static generalization cap
    /// </summary>
    // ------------------------------------------------------------------
    private static CustomLineCap mGeneralizationCap;

    #endregion

    #region Properties

    // ------------------------------------------------------------------
    /// <summary>
    /// Gets the current version.
    /// </summary>
    // ------------------------------------------------------------------
    public override double Version {
      get {
        return linePenStyleVersion;
      }
    }

    /// <summary>
    /// Gets the 'generallization cap'. This <see cref="CustomLineCap"/> is an arrow used in UML diagram to emphasize a generalization
    /// of an object, i.e. an object is inherited and expanded or generalized.
    /// </summary>
    /// <value>The generallization cap.</value>
    public static CustomLineCap GenerallizationCap {
      get {
        return mGeneralizationCap;
      }
    }

    /// <summary>
    /// Gets or sets the custom end cap.
    /// </summary>
    /// <value>The custom end cap.</value>
    public CustomLineCap CustomEndCap {
      get {
        return mCustomEndCap;
      }
      set {
        mCustomEndCap = value;
      }
    }

    /// <summary>
    /// Gets or sets the custom start cap.
    /// </summary>
    /// <value>The custom start cap.</value>
    public CustomLineCap CustomStartCap {
      get {
        return mCustomStartCap;
      }
      set {
        mCustomStartCap = value;
      }
    }

    /// <summary>
    /// Gets or sets the start cap.
    /// </summary>
    /// <value>The start cap.</value>
    public LineCap StartCap {
      get {
        return mStartCap;
      }
      set {
        mStartCap = value;
      }
    }

    /// <summary>
    /// Gets or sets the end cap.
    /// </summary>
    /// <value>The end cap.</value>
    public LineCap EndCap {
      get {
        return mEndCap;
      }
      set {
        mEndCap = value;
      }
    }
    /// <summary>
    /// The constructed pen
    /// </summary>
    /// <returns></returns>
    public override Pen DrawingPen() {
      Pen pen = base.DrawingPen();
      /*
       * Not a satisfying result, see the hack in the class comments above.
      pen.CustomEndCap = mCustomEndCap;
      pen.CustomStartCap = mCustomStartCap;
      pen.StartCap = mStartCap;
      pen.EndCap = mEndCap;
       */
      return pen;
    }
    #endregion

    #region Constructor

    /// <summary>
    /// Initializes the <see cref="T:LinePenStyle"/> class.
    /// </summary>
    static LinePenStyle() {
      Point[] ps = new Point[3] { new Point(-2, 0), new Point(0, 4), new Point(2, 0) };
      GraphicsPath gpath = new GraphicsPath();
      gpath.AddPolygon(ps);
      gpath.CloseAllFigures();
      mGeneralizationCap = new CustomLineCap(null, gpath);
    }

    public LinePenStyle() { }

    #endregion
  }
}