//
// (C) Copyright 2003-2019 by Autodesk, Inc.
//
// Permission to use, copy, modify, and distribute this software in
// object code form for any purpose and without fee is hereby granted,
// provided that the above copyright notice appears in all copies and
// that both that copyright notice and the limited warranty and
// restricted rights notice below appear in all supporting
// documentation.
//
// AUTODESK PROVIDES THIS PROGRAM "AS IS" AND WITH ALL FAULTS.
// AUTODESK SPECIFICALLY DISCLAIMS ANY IMPLIED WARRANTY OF
// MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. AUTODESK, INC.
// DOES NOT WARRANT THAT THE OPERATION OF THE PROGRAM WILL BE
// UNINTERRUPTED OR ERROR FREE.
//
// Use, duplication, or disclosure by the U.S. Government is subject to
// restrictions set forth in FAR 52.227-19 (Commercial Computer
// Software - Restricted Rights) and DFAR 252.227-7013(c)(1)(ii)
// (Rights in Technical Data and Computer Software), as applicable.
//

using System;
using System.Windows.Forms;
using System.Collections;
using System.Collections.Generic;

using Autodesk.Revit;
using Autodesk.Revit.DB;
using Autodesk.Revit.UI;
using Autodesk.Revit.UI.Selection;


namespace Revit.SDK.Samples.WorkThread.CS
{
    /// <summary>
    /// Implements the Revit add-in interface IExternalCommand
    /// </summary>
    [Autodesk.Revit.Attributes.Transaction(Autodesk.Revit.Attributes.TransactionMode.Manual)]
    [Autodesk.Revit.Attributes.Regeneration(Autodesk.Revit.Attributes.RegenerationOption.Manual)]
    public class Command : IExternalCommand
    {
        /// <summary>
        /// Implement this method as an external command for Revit.
        /// </summary>
        /// <param name="commandData">An object that is passed to the external application 
        /// which contains data related to the command, 
        /// such as the application object and active view.</param>
        /// <param name="message">A message that can be set by the external application 
        /// which will be displayed if a failure or cancellation is returned by 
        /// the external command.</param>
        /// <param name="elements">A set of elements to which the external application 
        /// can add elements that are to be highlighted in case of failure or cancellation.</param>
        /// <returns>Return the status of the external command. 
        /// A result of Succeeded means that the API external method functioned as expected. 
        /// Cancelled can be used to signify that the user cancelled the external operation 
        /// at some point. Failure should be returned if the application is unable to proceed with 
        /// the operation.</returns>
        public virtual Result Execute(ExternalCommandData commandData
            , ref string message, ElementSet elements)
        {
            try
            {
                UIDocument uidoc = commandData.Application.ActiveUIDocument;

                if (uidoc == null)
                {
                    // we can continue only if there is a document open
                    return Result.Cancelled;
                }

                // we ask the end-user to pick a face

                string sref = null;
                Result result = PickWallFace(uidoc, out sref);

                if (result == Result.Succeeded)
                {
                    // Start the analysis for the picked wall surface
                    Application.thisApp.RunAnalyzer(commandData.Application, sref);
                }
                else if (result == Result.Failed)
                {
                    message = "Did not picked a face on a Wall or FaceWall element!";
                }

                return Result.Succeeded;
            }
            catch (Exception ex)
            {
                message = ex.Message;
                return Result.Failed;
            }
        }

        /// <summary>
        ///   Prompting the user to pick a wall face
        /// </summary>
        /// <returns>
        ///   Returns 'Cancelled' if the end-user escapes from face picking.
        ///   Otherwise returns Succeeded or Failed depending on whether
        ///   a face on a wall or face-wall was picked as expected
        /// </returns>
        private Result PickWallFace(UIDocument uidoc, out String sref)
        {
            sref = null;
            Reference faceref = null;

            try
            {
                faceref = uidoc.Selection.PickObject(ObjectType.Face, "Pick a face on a wall or face-wall element.");
            }
            catch (Autodesk.Revit.Exceptions.OperationCanceledException)
            {
                return Result.Cancelled;
            }

            // we make sure we have the expected kind of face reference

            if (faceref != null)
            {
                Element pickedelem = uidoc.Document.GetElement(faceref.ElementId);
                FaceWall asfacewall = pickedelem as FaceWall;
                Wall aswall = pickedelem as Wall;

                // in this particular example, we accepts faces on wall elements only

                if ((aswall == null) && (asfacewall == null))
                {
                    return Result.Failed;
                }
            }

            // we convert the reference object to a more stable string
            // representation that is more traceable  across transactions

            sref = faceref.ConvertToStableRepresentation(uidoc.Document);

            return Result.Succeeded;
        }
    }
}