using System;
using System.Diagnostics;
using System.Collections;
using System.Drawing;
using System.Windows.Forms;

namespace Netron.Diagramming.Core {

  class ConnectionTool : AbstractTool, IMouseListener {

    #region Fields
    /// <summary>
    /// the location of the mouse when the motion starts
    /// </summary>
    private Point initialPoint;
    private bool doDraw;
    #endregion

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

    #region Methods

    /// <summary>
    /// Called when the tool is activated.
    /// </summary>
    protected override void OnActivateTool() {
      Controller.View.CurrentCursor = CursorPalette.Grip;
      this.SuspendOtherTools();
      doDraw = false;
    }

    /// <summary>
    /// Handles the mouse down event
    /// </summary>
    /// <param name="e">The <see cref="T:System.Windows.Forms.MouseEventArgs"/> instance containing the event data.</param>
    /// <returns>Returns 'true' if the event was handled, otherwise 'false'.</returns>
    public bool MouseDown(MouseEventArgs e) {
      if (e == null)
        throw new ArgumentNullException("The argument object is 'null'");
      if (e.Button == MouseButtons.Left && Enabled && !IsSuspended) {

        initialPoint = e.Location;
        doDraw = true;
        return true;
      }
      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'");
      Point point = e.Location;
      if (IsActive) {
        if (foundConnector != null)
          foundConnector.Hovered = false;
        foundConnector = this.Controller.Model.Selection.FindConnectorAt(e.Location);
        if (foundConnector != null)
          foundConnector.Hovered = true;
      }
      if (IsActive && doDraw) {
        Controller.View.PaintGhostLine(initialPoint, point);
        Controller.View.Invalidate(System.Drawing.Rectangle.Inflate(Controller.View.Ghost.Rectangle, 20, 20));


      }
    }
    private IConnector foundConnector;
    /// <summary>
    /// 
    /// </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) {
        // First, make sure the initial point is far enough away from 
        // the final point to make a connection.
        int maxX = Math.Abs(Math.Max(initialPoint.X, e.Location.X));
        int maxY = Math.Abs(Math.Max(initialPoint.Y, e.Location.Y));

        if (!(maxX > ConnectionBase.MinLength) ||
            !(maxY > ConnectionBase.MinLength)) {
          return;
        }

        //whatever comes hereafter, a compund command is the most economic approach
        CompoundCommand package = new CompoundCommand(this.Controller);

        //let's see if the connection endpoints hit other connectors
        //note that the following can be done because the actual connection has not been created yet
        //otherwise the search would find the endpoints of the newly created connection, which
        //would create a loop and a stack overflow!
        IConnector startConnector = this.Controller.Model.Selection.FindConnectorAt(initialPoint);
        IConnector endConnector = this.Controller.Model.Selection.FindConnectorAt(e.Location);

        #region Create the new connection
        Connection cn = new Connection(this.initialPoint, e.Location, this.Controller.Model);
        AddConnectionCommand newcon = new AddConnectionCommand(this.Controller, cn);

        #endregion

        #region Initial attachment?
        if (startConnector != null) {
          BindConnectorsCommand bindStart = new BindConnectorsCommand(this.Controller, startConnector, cn.From);
          package.Commands.Add(bindStart);
        }
        #endregion

        #region Final attachment?
        if (endConnector != null) {
          BindConnectorsCommand bindEnd = new BindConnectorsCommand(this.Controller, endConnector, cn.To);
          package.Commands.Add(bindEnd);
        }
        #endregion
        package.Text = "New connection";
        package.Commands.Add(newcon);
        this.Controller.UndoManager.AddUndoCommand(package);

        //do it all
        package.Redo();

        //reset highlight of the found connector
        if (foundConnector != null)
          foundConnector.Hovered = false;
        //drop the painted ghost
        Controller.View.ResetGhost();
        this.doDraw = false;
      }
    }
    #endregion
  }

}