using System;
using System.Drawing;
using System.Windows.Forms;

namespace Netron.Diagramming.Core {
  // ----------------------------------------------------------------------
  /// <summary>
  /// This tool implements the standard rectangular selection mechanism. 
  /// There are two modes (much like Visio).
  /// <list type="bullet">
  /// <item><term>Inclusive</term><description>elements are selected if 
  /// they are contained in the selection rectangle</description></item>
  /// <item><term>Touching</term><description>elements are selected if the 
  /// selection rectangle has an overlap with the element</description>
  /// </item>
  /// </list>
  /// <para>Note that this tool is slightly different than other tools 
  /// since it activates itself unless it has been suspended by another 
  /// tool. </para>
  /// </summary>
  // ----------------------------------------------------------------------
  public class SelectionTool : AbstractTool, IMouseListener {
    #region Fields

    // ------------------------------------------------------------------
    /// <summary>
    /// The location of the mouse when the motion starts.
    /// </summary>
    // ------------------------------------------------------------------
    private Point initialPoint;

    #endregion

    #region Constructor
    /// <summary>
    /// Initializes a new instance of the <see cref="T:SelectionTool"/> class.
    /// </summary>
    /// <param name="name">The name of the tool.</param>
    public SelectionTool(string name)
      : base(name) {
    }
    #endregion

    #region Methods

    // ------------------------------------------------------------------
    /// <summary>
    /// Called when the tool is activated.
    /// </summary>
    // ------------------------------------------------------------------
    protected override void OnActivateTool() {
      Controller.View.CurrentCursor = CursorPalette.Selection;
    }

    // ------------------------------------------------------------------
    /// <summary>
    /// Handles the mouse down event.
    /// </summary>
    /// <param name="e">The 
    /// <see cref="T:System.Windows.Forms.MouseEventArgs"/> instance 
    /// containing the event data.</param>
    // ------------------------------------------------------------------
    public bool MouseDown(MouseEventArgs e) {
      if (e == null)
        throw new ArgumentNullException(
            "The argument object is 'null'");

      if (e.Button == MouseButtons.Left && Enabled && !IsSuspended) {
        if (this.Controller.Model.Selection.SelectedItems.Count == 0 && this.Controller.Model.Selection.Connector == null) {
          initialPoint = e.Location;
          ActivateTool();
          return true;// This tells the tool-loop to stop looking 
          // for another handler, which keeps the CPU low.
        }
      }
      return false;
    }

    // ------------------------------------------------------------------
    /// <summary>
    /// Handles the mouse move event.
    /// </summary>
    /// <param name="e">The 
    /// <see cref="T:System.Windows.Forms.MouseEventArgs"/> instance 
    /// containing the event data.</param>
    // ------------------------------------------------------------------
    public void MouseMove(MouseEventArgs e) {
      if (e == null)
        throw new ArgumentNullException(
            "The argument object is 'null'");
      IView view = this.Controller.View;
      Point point = e.Location;
      if (IsActive && !IsSuspended) {
        Controller.View.PaintGhostRectangle(initialPoint, point);
        Rectangle rec = System.Drawing.Rectangle.Inflate(
            Controller.View.Ghost.Rectangle, 20, 20);

        Controller.View.Invalidate(rec);
      }
    }

    // ------------------------------------------------------------------
    /// <summary>
    /// Handles the mouse up event.
    /// </summary>
    /// <param name="e">The 
    /// <see cref="T:System.Windows.Forms.MouseEventArgs"/> instance 
    /// containing the event data.</param>
    // ------------------------------------------------------------------
    public void MouseUp(MouseEventArgs e) {
      if (IsActive) {
        DeactivateTool();
        if (Controller.View.Ghost != null) {
          this.Controller.Model.Selection.CollectEntitiesInside(
               Controller.View.Ghost.Rectangle);//world space

          Controller.RaiseOnShowSelectionProperties(
              new SelectionEventArgs(
             this.Controller.Model.Selection.SelectedItems.ToArray()));
        }
        Controller.View.ResetGhost();
      }
    }
    #endregion
  }

}