using System;
using System.Collections.Generic;
using System.Linq;
using Autodesk.Revit.Attributes;
using Autodesk.Revit.DB;
using Autodesk.Revit.UI;
using Autodesk.Revit.UI.Selection;

namespace RevitCommands
{
    [Transaction(TransactionMode.Manual)]
    [Regeneration(RegenerationOption.Manual)]
    public class HighlightDoorsInLinkedModel : IExternalCommand
    {
        public Result Execute(ExternalCommandData commandData, ref string message, ElementSet elements)
        {
            var uiDoc = commandData.Application.ActiveUIDocument;
            var doc = uiDoc.Document;

            try
            {
                // Get the currently selected element
                var selectedIds = uiDoc.Selection.GetElementIds();

                if (selectedIds.Count == 0)
                {
                    TaskDialog.Show("Error", "Please select a linked Revit model first.");
                    return Result.Failed;
                }

                // Find the first RevitLinkInstance in the selection
                RevitLinkInstance linkInstance = null;
                foreach (var id in selectedIds)
                {
                    var elem = doc.GetElement(id);
                    if (elem is RevitLinkInstance)
                    {
                        linkInstance = elem as RevitLinkInstance;
                        break;
                    }
                }

                if (linkInstance == null)
                {
                    TaskDialog.Show("Error", "Selected element is not a linked Revit model.");
                    return Result.Failed;
                }

                // Get the linked document
                var linkedDoc = linkInstance.GetLinkDocument();
                if (linkedDoc == null)
                {
                    TaskDialog.Show("Error", "Cannot access the linked document. Make sure it's loaded.");
                    return Result.Failed;
                }

                // Find all doors in the linked document
                var doorCollector = new FilteredElementCollector(linkedDoc)
                    .OfCategory(BuiltInCategory.OST_Doors)
                    .WhereElementIsNotElementType();

                var doors = doorCollector.ToElements();

                if (!doors.Any())
                {
                    TaskDialog.Show("Info", "No doors found in the linked model.");
                    return Result.Succeeded;
                }

                // Create references for all doors
                var doorReferences = new List<Reference>();

                foreach (var door in doors)
                {
                    try
                    {
                        // Create a reference for the door element
                        var doorRef = new Reference(door);

                        // Convert the reference to be readable from the current document
                        var linkedRef = doorRef.CreateLinkReference(linkInstance);

                        if (linkedRef != null)
                        {
                            doorReferences.Add(linkedRef);
                        }
                    }
                    catch (Exception ex)
                    {
                        // Some elements might not be able to create references
                        // Continue with the next door
                        continue;
                    }
                }

                if (doorReferences.Count > 0)
                {
                    // Highlight all door references
                    uiDoc.Selection.SetReferences(doorReferences);

                    TaskDialog.Show("Success",
                        $"Highlighted {doorReferences.Count} doors in the linked model.");
                }
                else
                {
                    TaskDialog.Show("Warning",
                        "Found doors but couldn't create references for highlighting.");
                }

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

    // Alternative version that prompts user to pick a linked model
    [Transaction(TransactionMode.Manual)]
    [Regeneration(RegenerationOption.Manual)]
    public class HighlightDoorsInPickedLinkedModel : IExternalCommand
    {
        public Result Execute(ExternalCommandData commandData, ref string message, ElementSet elements)
        {
            var uiDoc = commandData.Application.ActiveUIDocument;
            var doc = uiDoc.Document;

            try
            {
                // Create a filter for RevitLinkInstance
                var linkFilter = new LinkInstanceSelectionFilter();

                // Prompt user to select a linked model
                var pickedRef = uiDoc.Selection.PickObject(
                    ObjectType.Element,
                    linkFilter,
                    "Select a linked Revit model");

                if (pickedRef == null)
                {
                    return Result.Cancelled;
                }

                // Get the RevitLinkInstance
                var linkInstance = doc.GetElement(pickedRef) as RevitLinkInstance;

                if (linkInstance == null)
                {
                    TaskDialog.Show("Error", "Failed to get the linked model.");
                    return Result.Failed;
                }

                // Get the linked document
                var linkedDoc = linkInstance.GetLinkDocument();
                if (linkedDoc == null)
                {
                    TaskDialog.Show("Error", "Cannot access the linked document. Make sure it's loaded.");
                    return Result.Failed;
                }

                // Find all doors in the linked document
                var doorCollector = new FilteredElementCollector(linkedDoc)
                    .OfCategory(BuiltInCategory.OST_Doors)
                    .WhereElementIsNotElementType();

                var doors = doorCollector.ToElements();

                if (!doors.Any())
                {
                    TaskDialog.Show("Info", "No doors found in the linked model.");
                    return Result.Succeeded;
                }

                // Create references for all doors
                var doorReferences = new List<Reference>();

                foreach (var door in doors)
                {
                    try
                    {
                        // Create a reference for the door element
                        var doorRef = new Reference(door);

                        // Convert the reference to be readable from the current document
                        var linkedRef = doorRef.CreateLinkReference(linkInstance);

                        if (linkedRef != null)
                        {
                            doorReferences.Add(linkedRef);
                        }
                    }
                    catch (Exception ex)
                    {
                        // Some elements might not be able to create references
                        // Continue with the next door
                        continue;
                    }
                }

                if (doorReferences.Count > 0)
                {
                    // Highlight all door references
                    uiDoc.Selection.SetReferences(doorReferences);

                    TaskDialog.Show("Success",
                        $"Highlighted {doorReferences.Count} doors in '{linkInstance.Name}'.");
                }
                else
                {
                    TaskDialog.Show("Warning",
                        "Found doors but couldn't create references for highlighting.");
                }

                return Result.Succeeded;
            }
            catch (Autodesk.Revit.Exceptions.OperationCanceledException)
            {
                return Result.Cancelled;
            }
            catch (Exception ex)
            {
                message = ex.Message;
                return Result.Failed;
            }
        }

        // Selection filter for RevitLinkInstance
        private class LinkInstanceSelectionFilter : ISelectionFilter
        {
            public bool AllowElement(Element elem)
            {
                return elem is RevitLinkInstance;
            }

            public bool AllowReference(Reference reference, XYZ position)
            {
                return false;
            }
        }
    }
}