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

namespace WeifenLuo.WinFormsUI.Docking {
  partial class DockPane {
    private class SplitterControl : Control, ISplitterDragSource {
      DockPane m_pane;

      public SplitterControl(DockPane pane) {
        SetStyle(ControlStyles.Selectable, false);
        m_pane = pane;
      }

      public DockPane DockPane {
        get { return m_pane; }
      }

      private DockAlignment m_alignment;
      public DockAlignment Alignment {
        get { return m_alignment; }
        set {
          m_alignment = value;
          if (m_alignment == DockAlignment.Left || m_alignment == DockAlignment.Right)
            Cursor = Cursors.VSplit;
          else if (m_alignment == DockAlignment.Top || m_alignment == DockAlignment.Bottom)
            Cursor = Cursors.HSplit;
          else
            Cursor = Cursors.Default;

          if (DockPane.DockState == DockState.Document)
            Invalidate();
        }
      }

      protected override void OnPaint(PaintEventArgs e) {
        base.OnPaint(e);

        if (DockPane.DockState != DockState.Document)
          return;

        Graphics g = e.Graphics;
        Rectangle rect = ClientRectangle;
        if (Alignment == DockAlignment.Top || Alignment == DockAlignment.Bottom)
          g.DrawLine(SystemPens.ControlDark, rect.Left, rect.Bottom - 1, rect.Right, rect.Bottom - 1);
        else if (Alignment == DockAlignment.Left || Alignment == DockAlignment.Right)
          g.DrawLine(SystemPens.ControlDarkDark, rect.Right - 1, rect.Top, rect.Right - 1, rect.Bottom);
      }

      protected override void OnMouseDown(MouseEventArgs e) {
        base.OnMouseDown(e);

        if (e.Button != MouseButtons.Left)
          return;

        DockPane.DockPanel.BeginDrag(this, Parent.RectangleToScreen(Bounds));
      }

      #region ISplitterDragSource Members

      void ISplitterDragSource.BeginDrag(Rectangle rectSplitter) {
      }

      void ISplitterDragSource.EndDrag() {
      }

      bool ISplitterDragSource.IsVertical {
        get {
          NestedDockingStatus status = DockPane.NestedDockingStatus;
          return (status.DisplayingAlignment == DockAlignment.Left ||
              status.DisplayingAlignment == DockAlignment.Right);
        }
      }

      Rectangle ISplitterDragSource.DragLimitBounds {
        get {
          NestedDockingStatus status = DockPane.NestedDockingStatus;
          Rectangle rectLimit = Parent.RectangleToScreen(status.LogicalBounds);
          if (((ISplitterDragSource)this).IsVertical) {
            rectLimit.X += MeasurePane.MinSize;
            rectLimit.Width -= 2 * MeasurePane.MinSize;
          } else {
            rectLimit.Y += MeasurePane.MinSize;
            rectLimit.Height -= 2 * MeasurePane.MinSize;
          }

          return rectLimit;
        }
      }

      void ISplitterDragSource.MoveSplitter(int offset) {
        NestedDockingStatus status = DockPane.NestedDockingStatus;
        double proportion = status.Proportion;
        if (status.LogicalBounds.Width <= 0 || status.LogicalBounds.Height <= 0)
          return;
        else if (status.DisplayingAlignment == DockAlignment.Left)
          proportion += ((double)offset) / (double)status.LogicalBounds.Width;
        else if (status.DisplayingAlignment == DockAlignment.Right)
          proportion -= ((double)offset) / (double)status.LogicalBounds.Width;
        else if (status.DisplayingAlignment == DockAlignment.Top)
          proportion += ((double)offset) / (double)status.LogicalBounds.Height;
        else
          proportion -= ((double)offset) / (double)status.LogicalBounds.Height;

        DockPane.SetNestedDockingProportion(proportion);
      }

      #region IDragSource Members

      Control IDragSource.DragControl {
        get { return this; }
      }

      #endregion

      #endregion
    }

    private SplitterControl m_splitter;
    private SplitterControl Splitter {
      get { return m_splitter; }
    }

    internal Rectangle SplitterBounds {
      set { Splitter.Bounds = value; }
    }

    internal DockAlignment SplitterAlignment {
      set { Splitter.Alignment = value; }
    }
  }
}