// This code is part of the Fungus library (http://fungusgames.com) maintained by Chris Gregan (http://twitter.com/gofungus).
// It is released for free under the MIT open source license (https://github.com/snozbot/fungus/blob/master/LICENSE)

using UnityEditor;
using UnityEditorInternal;
using UnityEngine;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;
using System.IO;
using System.Reflection;

namespace Fungus.EditorUtils
{
    [CustomEditor(typeof(Block))]
    public class BlockEditor : Editor
    {
        protected class SetEventHandlerOperation
        {
            public Block block;
            public Type eventHandlerType;
        }

        protected class AddCommandOperation
        {
            public Type commandType;
        }


        private static readonly char[] SPLIT_INPUT_ON = new char[] { ' ', '/', '\\' };
        private static readonly int MAX_PREVIEW_GRID = 7;
        private static readonly string ELIPSIS = "...";

        public static List<Action> actionList = new List<Action>();

        protected Texture2D upIcon;
        protected Texture2D downIcon;
        protected Texture2D addIcon;
        protected Texture2D duplicateIcon;
        protected Texture2D deleteIcon;

        protected string commandTextFieldContents = string.Empty;
        protected int filteredCommandPreviewSelectedItem = 0;
        protected Type commandSelectedByTextInput;

        static List<System.Type> commandTypes;
        static List<System.Type> eventHandlerTypes;

        private CommandListAdaptor commandListAdaptor;
        private SerializedProperty commandListProperty;

        static void CacheEventHandlerTypes()
        {
            eventHandlerTypes = EditorExtensions.FindDerivedTypes(typeof(EventHandler)).ToList();
            commandTypes = EditorExtensions.FindDerivedTypes(typeof(Command)).ToList();
        }

        [UnityEditor.Callbacks.DidReloadScripts]
        private static void OnScriptsReloaded()
        {
            CacheEventHandlerTypes();
        }

        protected virtual void OnEnable()
        {
            //this appears to happen when leaving playmode
            try
            {
                if (serializedObject == null)
                    return;
            }
            catch (Exception)
            {
                return;
            }

            upIcon = FungusEditorResources.Up;
            downIcon = FungusEditorResources.Down;
            addIcon = FungusEditorResources.Add;
            duplicateIcon = FungusEditorResources.Duplicate;
            deleteIcon = FungusEditorResources.Delete;

            commandListProperty = serializedObject.FindProperty("commandList");

            commandListAdaptor = new CommandListAdaptor(target as Block, commandListProperty);

            CacheEventHandlerTypes();
        }

        public virtual void DrawBlockName(Flowchart flowchart)
        {
            serializedObject.Update();

            SerializedProperty blockNameProperty = serializedObject.FindProperty("blockName");
            Rect blockLabelRect = new Rect(45, 5, 120, 16);
            EditorGUI.LabelField(blockLabelRect, new GUIContent("Block Name"));
            Rect blockNameRect = new Rect(45, 21, 180, 16);
            EditorGUI.PropertyField(blockNameRect, blockNameProperty, new GUIContent(""));

            // Ensure block name is unique for this Flowchart
            var block = target as Block;
            string uniqueName = flowchart.GetUniqueBlockKey(blockNameProperty.stringValue, block);
            if (uniqueName != block.BlockName)
            {
                blockNameProperty.stringValue = uniqueName;
            }

            serializedObject.ApplyModifiedProperties();
        }

        public virtual void DrawBlockGUI(Flowchart flowchart)
        {
            serializedObject.Update();

            var block = target as Block;

            // Execute any queued cut, copy, paste, etc. operations from the prevous GUI update
            // We need to defer applying these operations until the following update because
            // the ReorderableList control emits GUI errors if you clear the list in the same frame
            // as drawing the control (e.g. select all and then delete)
            if (Event.current.type == EventType.Layout)
            {
                foreach (Action action in actionList)
                {
                    if (action != null)
                    {
                        action();
                    }
                }
                actionList.Clear();
            }


            if (block == flowchart.SelectedBlock)
            {
                // Custom tinting
                SerializedProperty useCustomTintProp = serializedObject.FindProperty("useCustomTint");
                SerializedProperty tintProp = serializedObject.FindProperty("tint");

                EditorGUILayout.BeginHorizontal();

                useCustomTintProp.boolValue = GUILayout.Toggle(useCustomTintProp.boolValue, " Custom Tint");
                if (useCustomTintProp.boolValue)
                {
                    EditorGUILayout.PropertyField(tintProp, GUIContent.none);
                }

                EditorGUILayout.EndHorizontal();

                SerializedProperty descriptionProp = serializedObject.FindProperty("description");
                EditorGUILayout.PropertyField(descriptionProp);

                DrawEventHandlerGUI(flowchart);

                block.UpdateIndentLevels();

                // Make sure each command has a reference to its parent block
                foreach (var command in block.CommandList)
                {
                    if (command == null) // Will be deleted from the list later on
                    {
                        continue;
                    }
                    command.ParentBlock = block;
                }

                commandListAdaptor.DrawCommandList();

                // EventType.contextClick doesn't register since we moved the Block Editor to be inside
                // a GUI Area, no idea why. As a workaround we just check for right click instead.
                if (Event.current.type == EventType.MouseUp &&
                    Event.current.button == 1)
                {
                    ShowContextMenu();
                    Event.current.Use();
                }

                if (GUIUtility.keyboardControl == 0) //Only call keyboard shortcuts when not typing in a text field
                {
                    Event e = Event.current;

                    // Copy keyboard shortcut
                    if (e.type == EventType.ValidateCommand && e.commandName == "Copy")
                    {
                        if (flowchart.SelectedCommands.Count > 0)
                        {
                            e.Use();
                        }
                    }

                    if (e.type == EventType.ExecuteCommand && e.commandName == "Copy")
                    {
                        actionList.Add(Copy);
                        e.Use();
                    }

                    // Cut keyboard shortcut
                    if (e.type == EventType.ValidateCommand && e.commandName == "Cut")
                    {
                        if (flowchart.SelectedCommands.Count > 0)
                        {
                            e.Use();
                        }
                    }

                    if (e.type == EventType.ExecuteCommand && e.commandName == "Cut")
                    {
                        actionList.Add(Cut);
                        e.Use();
                    }

                    // Paste keyboard shortcut
                    if (e.type == EventType.ValidateCommand && e.commandName == "Paste")
                    {
                        CommandCopyBuffer commandCopyBuffer = CommandCopyBuffer.GetInstance();
                        if (commandCopyBuffer.HasCommands())
                        {
                            e.Use();
                        }
                    }

                    if (e.type == EventType.ExecuteCommand && e.commandName == "Paste")
                    {
                        actionList.Add(Paste);
                        e.Use();
                    }

                    // Duplicate keyboard shortcut
                    if (e.type == EventType.ValidateCommand && e.commandName == "Duplicate")
                    {
                        if (flowchart.SelectedCommands.Count > 0)
                        {
                            e.Use();
                        }
                    }

                    if (e.type == EventType.ExecuteCommand && e.commandName == "Duplicate")
                    {
                        actionList.Add(Copy);
                        actionList.Add(Paste);
                        e.Use();
                    }

                    // Delete keyboard shortcut
                    if (e.type == EventType.ValidateCommand && e.commandName == "Delete")
                    {
                        if (flowchart.SelectedCommands.Count > 0)
                        {
                            e.Use();
                        }
                    }

                    if (e.type == EventType.ExecuteCommand && e.commandName == "Delete")
                    {
                        actionList.Add(Delete);
                        e.Use();
                    }

                    // SelectAll keyboard shortcut
                    if (e.type == EventType.ValidateCommand && e.commandName == "SelectAll")
                    {
                        e.Use();
                    }

                    if (e.type == EventType.ExecuteCommand && e.commandName == "SelectAll")
                    {
                        actionList.Add(SelectAll);
                        e.Use();
                    }
                }
            }

            // Remove any null entries in the command list.
            // This can happen when a command class is deleted or renamed.
            for (int i = commandListProperty.arraySize - 1; i >= 0; --i)
            {
                SerializedProperty commandProperty = commandListProperty.GetArrayElementAtIndex(i);
                if (commandProperty.objectReferenceValue == null)
                {
                    commandListProperty.DeleteArrayElementAtIndex(i);
                }
            }

            serializedObject.ApplyModifiedProperties();
        }

        public virtual void DrawButtonToolbar()
        {
            GUILayout.BeginHorizontal();



            //handle movement along our selection grid before something else eats our inputs
            if (Event.current.type == EventType.KeyDown)
            {
                //up down to change selection / esc to clear field
                if (Event.current.keyCode == KeyCode.UpArrow)
                {
                    filteredCommandPreviewSelectedItem--;
                }
                else if (Event.current.keyCode == KeyCode.DownArrow)
                {
                    filteredCommandPreviewSelectedItem++;
                }

                if (commandSelectedByTextInput != null &&
                    Event.current.keyCode == KeyCode.Return || Event.current.keyCode == KeyCode.KeypadEnter)
                {
                    AddCommandCallback(commandSelectedByTextInput);
                    commandSelectedByTextInput = null;
                    commandTextFieldContents = String.Empty;
                    //GUI.FocusControl("dummycontrol");
                    Event.current.Use();
                    filteredCommandPreviewSelectedItem = 0;
                }
            }

            // Previous Command
            if ((Event.current.type == EventType.KeyDown) && (Event.current.keyCode == KeyCode.PageUp))
            {
                SelectPrevious();
                GUI.FocusControl("dummycontrol");
                Event.current.Use();
            }
            // Next Command
            if ((Event.current.type == EventType.KeyDown) && (Event.current.keyCode == KeyCode.PageDown))
            {
                SelectNext();
                GUI.FocusControl("dummycontrol");
                Event.current.Use();
            }

            if (GUILayout.Button(upIcon))
            {
                SelectPrevious();
            }

            // Down Button
            if (GUILayout.Button(downIcon))
            {
                SelectNext();
            }

            GUILayout.FlexibleSpace();

            //should track if text actually changes and pass that to the ShowPartialMatches so it can cache
            commandTextFieldContents = GUILayout.TextField(commandTextFieldContents, GUILayout.MinWidth(20), GUILayout.MaxWidth(200));

            // Add Button
            if (GUILayout.Button(addIcon))
            {
                ShowCommandMenu();
            }

            // Duplicate Button
            if (GUILayout.Button(duplicateIcon))
            {
                Copy();
                Paste();
            }

            // Delete Button
            if (GUILayout.Button(deleteIcon))
            {
                Delete();
            }

            GUILayout.EndHorizontal();

            if (!string.IsNullOrEmpty(commandTextFieldContents))
                ShowPartialMatches();

        }

        //Handles showing partial matches against the text input next to the AddCommand button
        // Splits and matches and can use up down arrows and return/enter/numenter to confirm
        //  TODO add sorting of results so we get best match at the not just just a match
        //      e.g. "if" should show Flow/If at the top not Flow/Else If
        private void ShowPartialMatches()
        {
            var block = target as Block;

            var flowchart = (Flowchart)block.GetFlowchart();

            //TODO this could be cached if input hasn't changed to avoid thrashing
            var filteredAttributes = GetFilteredSupportedCommands(flowchart);

            var upperCommandText = commandTextFieldContents.ToUpper().Trim();

            if (upperCommandText.Length == 0)
                return;

            var tokens = upperCommandText.Split(SPLIT_INPUT_ON);

            //we want commands that have all the elements you have typed
            filteredAttributes = filteredAttributes.Where((x) =>
            {
                bool catAny = tokens.Any(x.Value.Category.ToUpper().Contains);
                bool comAny = tokens.Any(x.Value.CommandName.ToUpper().Contains);
                bool catAll = tokens.All(x.Value.Category.ToUpper().Contains);
                bool comAll = tokens.All(x.Value.CommandName.ToUpper().Contains);

                //so if both category and command found something, then there are multiple tokens and they line up with category and command
                if (catAny && comAny)
                    return true;
                //or its a single token or a complex token that matches entirely in cat or com
                else if (catAll || comAll)
                    return true;
                //this setup avoids multiple bad suggestions due to a complex category name that gives many false matches on complex partials

                return false;

            }).ToList();

            if (filteredAttributes == null || filteredAttributes.Count == 0)
                return;

            //show results
            GUILayout.Space(5);

            GUILayout.BeginHorizontal();

            filteredCommandPreviewSelectedItem = Mathf.Clamp(filteredCommandPreviewSelectedItem, 0, filteredAttributes.Count - 1);

            var toShow = filteredAttributes.Select(x => x.Value.Category + "/" + x.Value.CommandName).ToArray();

            //show the first x max that match our filters
            if(toShow.Length > MAX_PREVIEW_GRID)
            {
                toShow = toShow.Take(MAX_PREVIEW_GRID).ToArray();
                toShow[MAX_PREVIEW_GRID - 1] = ELIPSIS;
            }

            filteredCommandPreviewSelectedItem = GUILayout.SelectionGrid(filteredCommandPreviewSelectedItem, toShow, 1);

            if (toShow[filteredCommandPreviewSelectedItem] != ELIPSIS)
            {
                commandSelectedByTextInput = filteredAttributes[filteredCommandPreviewSelectedItem].Key;
            }
            else
            {
                commandSelectedByTextInput = null;
            }

            GUILayout.EndHorizontal();

            GUILayout.Space(5);
        }

        protected virtual void DrawEventHandlerGUI(Flowchart flowchart)
        {
            // Show available Event Handlers in a drop down list with type of current
            // event handler selected.
            Block block = target as Block;
            System.Type currentType = null;
            if (block._EventHandler != null)
            {
                currentType = block._EventHandler.GetType();
            }

            string currentHandlerName = "<None>";
            if (currentType != null)
            {
                EventHandlerInfoAttribute info = EventHandlerEditor.GetEventHandlerInfo(currentType);
                if (info != null)
                {
                    currentHandlerName = info.EventHandlerName;
                }
            }

            EditorGUILayout.BeginHorizontal();
            EditorGUILayout.PrefixLabel(new GUIContent("Execute On Event"));
            if (GUILayout.Button(new GUIContent(currentHandlerName), EditorStyles.popup))
            {
                SetEventHandlerOperation noneOperation = new SetEventHandlerOperation();
                noneOperation.block = block;
                noneOperation.eventHandlerType = null;

                GenericMenu eventHandlerMenu = new GenericMenu();
                eventHandlerMenu.AddItem(new GUIContent("None"), false, OnSelectEventHandler, noneOperation);

                // Add event handlers with no category first
                foreach (System.Type type in eventHandlerTypes)
                {
                    EventHandlerInfoAttribute info = EventHandlerEditor.GetEventHandlerInfo(type);
                    if (info != null &&
                        info.Category.Length == 0)
                    {
                        SetEventHandlerOperation operation = new SetEventHandlerOperation();
                        operation.block = block;
                        operation.eventHandlerType = type;

                        eventHandlerMenu.AddItem(new GUIContent(info.EventHandlerName), false, OnSelectEventHandler, operation);
                    }
                }

                // Add event handlers with a category afterwards
                foreach (System.Type type in eventHandlerTypes)
                {
                    EventHandlerInfoAttribute info = EventHandlerEditor.GetEventHandlerInfo(type);
                    if (info != null &&
                        info.Category.Length > 0)
                    {
                        SetEventHandlerOperation operation = new SetEventHandlerOperation();
                        operation.block = block;
                        operation.eventHandlerType = type;
                        string typeName = info.Category + "/" + info.EventHandlerName;
                        eventHandlerMenu.AddItem(new GUIContent(typeName), false, OnSelectEventHandler, operation);
                    }
                }


                eventHandlerMenu.ShowAsContext();
            }
            EditorGUILayout.EndHorizontal();

            if (block._EventHandler != null)
            {
                EventHandlerEditor eventHandlerEditor = Editor.CreateEditor(block._EventHandler) as EventHandlerEditor;
                if (eventHandlerEditor != null)
                {
                    eventHandlerEditor.DrawInspectorGUI();
                    DestroyImmediate(eventHandlerEditor);
                }
            }
        }

        protected void OnSelectEventHandler(object obj)
        {
            SetEventHandlerOperation operation = obj as SetEventHandlerOperation;
            Block block = operation.block;
            System.Type selectedType = operation.eventHandlerType;
            if (block == null)
            {
                return;
            }

            Undo.RecordObject(block, "Set Event Handler");

            if (block._EventHandler != null)
            {
                Undo.DestroyObjectImmediate(block._EventHandler);
            }

            if (selectedType != null)
            {
                EventHandler newHandler = Undo.AddComponent(block.gameObject, selectedType) as EventHandler;
                newHandler.ParentBlock = block;
                block._EventHandler = newHandler;
            }

            // Because this is an async call, we need to force prefab instances to record changes
            PrefabUtility.RecordPrefabInstancePropertyModifications(block);
        }

        public static void BlockField(SerializedProperty property, GUIContent label, GUIContent nullLabel, Flowchart flowchart)
        {
            if (flowchart == null)
            {
                return;
            }

            var block = property.objectReferenceValue as Block;

            // Build dictionary of child blocks
            List<GUIContent> blockNames = new List<GUIContent>();

            int selectedIndex = 0;
            blockNames.Add(nullLabel);
            var blocks = flowchart.GetComponents<Block>();
            for (int i = 0; i < blocks.Length; ++i)
            {
                blockNames.Add(new GUIContent(blocks[i].BlockName));

                if (block == blocks[i])
                {
                    selectedIndex = i + 1;
                }
            }

            selectedIndex = EditorGUILayout.Popup(label, selectedIndex, blockNames.ToArray());
            if (selectedIndex == 0)
            {
                block = null; // Option 'None'
            }
            else
            {
                block = blocks[selectedIndex - 1];
            }

            property.objectReferenceValue = block;
        }

        public static Block BlockField(Rect position, GUIContent nullLabel, Flowchart flowchart, Block block)
        {
            if (flowchart == null)
            {
                return null;
            }

            Block result = block;

            // Build dictionary of child blocks
            List<GUIContent> blockNames = new List<GUIContent>();

            int selectedIndex = 0;
            blockNames.Add(nullLabel);
            Block[] blocks = flowchart.GetComponents<Block>();
            for (int i = 0; i < blocks.Length; ++i)
            {
				blockNames.Add(new GUIContent(blocks[i].BlockName));

                if (block == blocks[i])
                {
                    selectedIndex = i + 1;
                }
            }

            selectedIndex = EditorGUI.Popup(position, selectedIndex, blockNames.ToArray());
            if (selectedIndex == 0)
            {
                result = null; // Option 'None'
            }
            else
            {
                result = blocks[selectedIndex - 1];
            }

            return result;
        }

        // Compare delegate for sorting the list of command attributes
        protected static int CompareCommandAttributes(KeyValuePair<System.Type, CommandInfoAttribute> x, KeyValuePair<System.Type, CommandInfoAttribute> y)
        {
            int compare = (x.Value.Category.CompareTo(y.Value.Category));
            if (compare == 0)
            {
                compare = (x.Value.CommandName.CompareTo(y.Value.CommandName));
            }
            return compare;
        }

        [MenuItem("Tools/Fungus/Utilities/Export Reference Docs")]
        protected static void ExportReferenceDocs()
        {
            const string path = "./Docs";

            ExportCommandInfo(path);
            ExportEventHandlerInfo(path);

            FlowchartWindow.ShowNotification("Exported Reference Documentation");
        }

        protected static void ExportCommandInfo(string path)
        {
            // Dump command info
            List<System.Type> menuTypes = EditorExtensions.FindDerivedTypes(typeof(Command)).ToList();
            List<KeyValuePair<System.Type, CommandInfoAttribute>> filteredAttributes = GetFilteredCommandInfoAttribute(menuTypes);
            filteredAttributes.Sort(CompareCommandAttributes);

            // Build list of command categories
            List<string> commandCategories = new List<string>();
            foreach (var keyPair in filteredAttributes)
            {
                CommandInfoAttribute info = keyPair.Value;
                if (info.Category != "" &&
                    !commandCategories.Contains(info.Category))
                {
                    commandCategories.Add(info.Category);
                }
            }
            commandCategories.Sort();

            // Output the commands in each category
            foreach (string category in commandCategories)
            {
                string markdown = "# " + category + " commands # {#" + category.ToLower() + "_commands}\n\n";
                markdown += "[TOC]\n";

                foreach (var keyPair in filteredAttributes)
                {
                    CommandInfoAttribute info = keyPair.Value;

                    if (info.Category == category ||
                        info.Category == "" && category == "Scripting")
                    {
                        markdown += "# " + info.CommandName + " # {#" + info.CommandName.Replace(" ", "") + "}\n";
                        markdown += info.HelpText + "\n\n";
                        markdown += "Defined in " + keyPair.Key.FullName + "\n";
                        markdown += GetPropertyInfo(keyPair.Key);
                    }
                }

                string filePath = path + "/command_ref/" + category.ToLower() + "_commands.md";

                Directory.CreateDirectory(Path.GetDirectoryName(filePath));
                File.WriteAllText(filePath, markdown);
            }
        }

        protected static void ExportEventHandlerInfo(string path)
        {
            List<System.Type> eventHandlerTypes = EditorExtensions.FindDerivedTypes(typeof(EventHandler)).ToList();
            List<string> eventHandlerCategories = new List<string>();
            eventHandlerCategories.Add("Core");
            foreach (System.Type type in eventHandlerTypes)
            {
                EventHandlerInfoAttribute info = EventHandlerEditor.GetEventHandlerInfo(type);
                if (info != null &&
                    info.Category != "" &&
                    !eventHandlerCategories.Contains(info.Category))
                {
                    eventHandlerCategories.Add(info.Category);
                }
            }
            eventHandlerCategories.Sort();

            // Output the commands in each category
            foreach (string category in eventHandlerCategories)
            {
                string markdown = "# " + category + " event handlers # {#" + category.ToLower() + "_events}\n\n";
                markdown += "[TOC]\n";

                foreach (System.Type type in eventHandlerTypes)
                {
                    EventHandlerInfoAttribute info = EventHandlerEditor.GetEventHandlerInfo(type);

                    if (info != null &&
                        (info.Category == category ||
                         (info.Category == "" && category == "Core")))
                    {
                        markdown += "# " + info.EventHandlerName + " # {#" + info.EventHandlerName.Replace(" ", "") + "}\n";
                        markdown += info.HelpText + "\n\n";
                        markdown += "Defined in " + type.FullName + "\n";
                        markdown += GetPropertyInfo(type);
                    }
                }

                string filePath = path + "/command_ref/" + category.ToLower() + "_events.md";

                Directory.CreateDirectory(Path.GetDirectoryName(filePath));
                File.WriteAllText(filePath, markdown);
            }
        }

        protected static string GetPropertyInfo(System.Type type)
        {
            string markdown = "";
            foreach (FieldInfo field in type.GetFields(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic))
            {
                TooltipAttribute attribute = (TooltipAttribute)Attribute.GetCustomAttribute(field, typeof(TooltipAttribute));
                if (attribute == null)
                {
                    continue;
                }

                // Change field name to how it's displayed in the inspector
                string propertyName = Regex.Replace(field.Name, "(\\B[A-Z])", " $1");
                if (propertyName.Length > 1)
                {
                    propertyName = propertyName.Substring(0, 1).ToUpper() + propertyName.Substring(1);
                }
                else
                {
                    propertyName = propertyName.ToUpper();
                }

                markdown += propertyName + " | " + field.FieldType + " | " + attribute.tooltip + "\n";
            }

            if (markdown.Length > 0)
            {
                markdown = "\nProperty | Type | Description\n --- | --- | ---\n" + markdown + "\n";
            }

            return markdown;
        }

        protected virtual void ShowCommandMenu()
        {
            var block = target as Block;

            var flowchart = (Flowchart)block.GetFlowchart();

            GenericMenu commandMenu = new GenericMenu();

            // Build menu list
            var filteredAttributes = GetFilteredSupportedCommands(flowchart);

            foreach (var keyPair in filteredAttributes)
            {
                AddCommandOperation commandOperation = new AddCommandOperation();
                
                commandOperation.commandType = keyPair.Key;

                GUIContent menuItem;
                if (keyPair.Value.Category == "")
                {
                    menuItem = new GUIContent(keyPair.Value.CommandName);
                }
                else
                {
                    menuItem = new GUIContent(keyPair.Value.Category + "/" + keyPair.Value.CommandName);
                }

                commandMenu.AddItem(menuItem, false, AddCommandCallback, commandOperation);
            }

            commandMenu.ShowAsContext();
        }

        protected static List<KeyValuePair<System.Type, CommandInfoAttribute>> GetFilteredSupportedCommands(Flowchart flowchart)
        {
            List<KeyValuePair<System.Type, CommandInfoAttribute>> filteredAttributes = GetFilteredCommandInfoAttribute(commandTypes);

            filteredAttributes.Sort(CompareCommandAttributes);

            filteredAttributes = filteredAttributes.Where(x => flowchart.IsCommandSupported(x.Value)).ToList();

            return filteredAttributes;
        }

        protected static List<KeyValuePair<System.Type, CommandInfoAttribute>> GetFilteredCommandInfoAttribute(List<System.Type> menuTypes)
        {
            Dictionary<string, KeyValuePair<System.Type, CommandInfoAttribute>> filteredAttributes = new Dictionary<string, KeyValuePair<System.Type, CommandInfoAttribute>>();

            foreach (System.Type type in menuTypes)
            {
                object[] attributes = type.GetCustomAttributes(false);
                foreach (object obj in attributes)
                {
                    CommandInfoAttribute infoAttr = obj as CommandInfoAttribute;
                    if (infoAttr != null)
                    {
                        string dictionaryName = string.Format("{0}/{1}", infoAttr.Category, infoAttr.CommandName);

                        int existingItemPriority = -1;
                        if (filteredAttributes.ContainsKey(dictionaryName))
                        {
                            existingItemPriority = filteredAttributes[dictionaryName].Value.Priority;
                        }

                        if (infoAttr.Priority > existingItemPriority)
                        {
                            KeyValuePair<System.Type, CommandInfoAttribute> keyValuePair = new KeyValuePair<System.Type, CommandInfoAttribute>(type, infoAttr);
                            filteredAttributes[dictionaryName] = keyValuePair;
                        }
                    }
                }
            }
            return filteredAttributes.Values.ToList<KeyValuePair<System.Type, CommandInfoAttribute>>();
        }

        //Used by GenericMenu Delegate
        protected void AddCommandCallback(object obj)
        {
            AddCommandOperation commandOperation = obj as AddCommandOperation;
            if (commandOperation != null)
            {
                AddCommandCallback(commandOperation.commandType);
            }
        }

        protected void AddCommandCallback(Type commandType)
        {
            var block = target as Block;
            if (block == null)
            {
                return;
            }

            var flowchart = (Flowchart)block.GetFlowchart();

            // Use index of last selected command in list, or end of list if nothing selected.
            int index = -1;
            foreach (var command in flowchart.SelectedCommands)
            {
                if (command.CommandIndex + 1 > index)
                {
                    index = command.CommandIndex + 1;
                }
            }
            if (index == -1)
            {
                index = block.CommandList.Count;
            }

            var newCommand = Undo.AddComponent(block.gameObject, commandType) as Command;
            block.GetFlowchart().AddSelectedCommand(newCommand);
            newCommand.ParentBlock = block;
            newCommand.ItemId = flowchart.NextItemId();

            // Let command know it has just been added to the block
            newCommand.OnCommandAdded(block);

            Undo.RecordObject(block, "Set command type");
            if (index < block.CommandList.Count - 1)
            {
                block.CommandList.Insert(index, newCommand);
            }
            else
            {
                block.CommandList.Add(newCommand);
            }

            // Because this is an async call, we need to force prefab instances to record changes
            PrefabUtility.RecordPrefabInstancePropertyModifications(block);

            flowchart.ClearSelectedCommands();

            commandTextFieldContents = string.Empty;
        }

        public virtual void ShowContextMenu()
        {
            var block = target as Block;
            var flowchart = (Flowchart)block.GetFlowchart();

            if (flowchart == null)
            {
                return;
            }

            bool showCut = false;
            bool showCopy = false;
            bool showDelete = false;
            bool showPaste = false;
            bool showPlay = false;

            if (flowchart.SelectedCommands.Count > 0)
            {
                showCut = true;
                showCopy = true;
                showDelete = true;
                if (flowchart.SelectedCommands.Count == 1 && Application.isPlaying)
                {
                    showPlay = true;
                }
            }



            CommandCopyBuffer commandCopyBuffer = CommandCopyBuffer.GetInstance();

            if (commandCopyBuffer.HasCommands())
            {
                showPaste = true;
            }

            GenericMenu commandMenu = new GenericMenu();

            if (showCut)
            {
                commandMenu.AddItem(new GUIContent("Cut"), false, Cut);
            }
            else
            {
                commandMenu.AddDisabledItem(new GUIContent("Cut"));
            }

            if (showCopy)
            {
                commandMenu.AddItem(new GUIContent("Copy"), false, Copy);
            }
            else
            {
                commandMenu.AddDisabledItem(new GUIContent("Copy"));
            }

            if (showPaste)
            {
                commandMenu.AddItem(new GUIContent("Paste"), false, Paste);
            }
            else
            {
                commandMenu.AddDisabledItem(new GUIContent("Paste"));
            }

            if (showDelete)
            {
                commandMenu.AddItem(new GUIContent("Delete"), false, Delete);
            }
            else
            {
                commandMenu.AddDisabledItem(new GUIContent("Delete"));
            }

            if (showPlay)
            {
                commandMenu.AddItem(new GUIContent("Play from selected"), false, PlayCommand);
                commandMenu.AddItem(new GUIContent("Stop all and play"), false, StopAllPlayCommand);
            }

            commandMenu.AddSeparator("");

            commandMenu.AddItem(new GUIContent("Select All"), false, SelectAll);
            commandMenu.AddItem(new GUIContent("Select None"), false, SelectNone);

            commandMenu.ShowAsContext();
        }

        protected void SelectAll()
        {
            var block = target as Block;
            var flowchart = (Flowchart)block.GetFlowchart();

            if (flowchart == null ||
                flowchart.SelectedBlock == null)
            {
                return;
            }

            flowchart.ClearSelectedCommands();
            Undo.RecordObject(flowchart, "Select All");
            foreach (Command command in flowchart.SelectedBlock.CommandList)
            {
                flowchart.AddSelectedCommand(command);
            }

            Repaint();
        }

        protected void SelectNone()
        {
            var block = target as Block;
            var flowchart = (Flowchart)block.GetFlowchart();

            if (flowchart == null ||
                flowchart.SelectedBlock == null)
            {
                return;
            }

            Undo.RecordObject(flowchart, "Select None");
            flowchart.ClearSelectedCommands();

            Repaint();
        }

        protected void Cut()
        {
            Copy();
            Delete();
        }

        protected void Copy()
        {
            var block = target as Block;
            var flowchart = (Flowchart)block.GetFlowchart();

            if (flowchart == null ||
                flowchart.SelectedBlock == null)
            {
                return;
            }

            CommandCopyBuffer commandCopyBuffer = CommandCopyBuffer.GetInstance();
            commandCopyBuffer.Clear();

            // Scan through all commands in execution order to see if each needs to be copied
            foreach (Command command in flowchart.SelectedBlock.CommandList)
            {
                if (flowchart.SelectedCommands.Contains(command))
                {
                    var type = command.GetType();
                    Command newCommand = Undo.AddComponent(commandCopyBuffer.gameObject, type) as Command;
                    var fields = type.GetFields(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.FlattenHierarchy);
                    foreach (var field in fields)
                    {
                        // Copy all public fields
                        bool copy = field.IsPublic;

                        // Copy non-public fields that have the SerializeField attribute
                        var attributes = field.GetCustomAttributes(typeof(SerializeField), true);
                        if (attributes.Length > 0)
                        {
                            copy = true;
                        }

                        if (copy)
                        {
                            field.SetValue(newCommand, field.GetValue(command));
                        }
                    }
                }
            }
        }

        protected void Paste()
        {
            var block = target as Block;
            var flowchart = (Flowchart)block.GetFlowchart();

            if (flowchart == null ||
                flowchart.SelectedBlock == null)
            {
                return;
            }

            CommandCopyBuffer commandCopyBuffer = CommandCopyBuffer.GetInstance();

            // Find where to paste commands in block (either at end or after last selected command)
            int pasteIndex = flowchart.SelectedBlock.CommandList.Count;
            if (flowchart.SelectedCommands.Count > 0)
            {
                for (int i = 0; i < flowchart.SelectedBlock.CommandList.Count; ++i)
                {
                    Command command = flowchart.SelectedBlock.CommandList[i];

                    foreach (Command selectedCommand in flowchart.SelectedCommands)
                    {
                        if (command == selectedCommand)
                        {
                            pasteIndex = i + 1;
                        }
                    }
                }
            }

            foreach (Command command in commandCopyBuffer.GetCommands())
            {
                // Using the Editor copy / paste functionality instead instead of reflection
                // because this does a deep copy of the command properties.
                if (ComponentUtility.CopyComponent(command))
                {
                    if (ComponentUtility.PasteComponentAsNew(flowchart.gameObject))
                    {
                        Command[] commands = flowchart.GetComponents<Command>();
                        Command pastedCommand = commands.Last<Command>();
                        if (pastedCommand != null)
                        {
                            pastedCommand.ItemId = flowchart.NextItemId();
                            flowchart.SelectedBlock.CommandList.Insert(pasteIndex++, pastedCommand);
                        }
                    }

                    // This stops the user pasting the command manually into another game object.
                    ComponentUtility.CopyComponent(flowchart.transform);
                }
            }

            // Because this is an async call, we need to force prefab instances to record changes
            PrefabUtility.RecordPrefabInstancePropertyModifications(block);

            Repaint();
        }

        protected void Delete()
        {
            var block = target as Block;
            var flowchart = (Flowchart)block.GetFlowchart();

            if (flowchart == null ||
                flowchart.SelectedBlock == null)
            {
                return;
            }
            int lastSelectedIndex = 0;
            for (int i = flowchart.SelectedBlock.CommandList.Count - 1; i >= 0; --i)
            {
                Command command = flowchart.SelectedBlock.CommandList[i];
                foreach (Command selectedCommand in flowchart.SelectedCommands)
                {
                    if (command == selectedCommand)
                    {
                        command.OnCommandRemoved(block);

                        // Order of destruction is important here for undo to work
                        Undo.DestroyObjectImmediate(command);

                        Undo.RecordObject((Block)flowchart.SelectedBlock, "Delete");
                        flowchart.SelectedBlock.CommandList.RemoveAt(i);

                        lastSelectedIndex = i;

                        break;
                    }
                }
            }

            Undo.RecordObject(flowchart, "Delete");
            flowchart.ClearSelectedCommands();

            if (lastSelectedIndex < flowchart.SelectedBlock.CommandList.Count)
            {
                var nextCommand = flowchart.SelectedBlock.CommandList[lastSelectedIndex];
                block.GetFlowchart().AddSelectedCommand(nextCommand);
            }

            Repaint();
        }

        protected void PlayCommand()
        {
            var targetBlock = target as Block;
            var flowchart = (Flowchart)targetBlock.GetFlowchart();
            Command command = flowchart.SelectedCommands[0];
            if (targetBlock.IsExecuting())
            {
                // The Block is already executing.
                // Tell the Block to stop, wait a little while so the executing command has a 
                // chance to stop, and then start execution again from the new command. 
                targetBlock.Stop();
                flowchart.StartCoroutine(RunBlock(flowchart, targetBlock, command.CommandIndex, 0.2f));
            }
            else
            {
                // Block isn't executing yet so can start it now.
                flowchart.ExecuteBlock(targetBlock, command.CommandIndex);
            }
        }

        protected void StopAllPlayCommand()
        {
            var targetBlock = target as Block;
            var flowchart = (Flowchart)targetBlock.GetFlowchart();
            Command command = flowchart.SelectedCommands[0];

            // Stop all active blocks then run the selected block.
            flowchart.StopAllBlocks();
            flowchart.StartCoroutine(RunBlock(flowchart, targetBlock, command.CommandIndex, 0.2f));
        }

        protected IEnumerator RunBlock(Flowchart flowchart, Block targetBlock, int commandIndex, float delay)
        {
            yield return new WaitForSeconds(delay);
            flowchart.ExecuteBlock(targetBlock, commandIndex);
        }

        protected void SelectPrevious()
        {
            var block = target as Block;
            var flowchart = (Flowchart)block.GetFlowchart();

            int firstSelectedIndex = flowchart.SelectedBlock.CommandList.Count;
            bool firstSelectedCommandFound = false;
            if (flowchart.SelectedCommands.Count > 0)
            {
                for (int i = 0; i < flowchart.SelectedBlock.CommandList.Count; i++)
                {
                    Command commandInBlock = flowchart.SelectedBlock.CommandList[i];

                    foreach (Command selectedCommand in flowchart.SelectedCommands)
                    {
                        if (commandInBlock == selectedCommand)
                        {
                            if (!firstSelectedCommandFound)
                            {
                                firstSelectedIndex = i;
                                firstSelectedCommandFound = true;
                                break;
                            }
                        }
                    }
                    if (firstSelectedCommandFound)
                    {
                        break;
                    }
                }
            }
            if (firstSelectedIndex > 0)
            {
                flowchart.ClearSelectedCommands();
                flowchart.AddSelectedCommand(flowchart.SelectedBlock.CommandList[firstSelectedIndex - 1]);
            }

            Repaint();
        }

        protected void SelectNext()
        {
            var block = target as Block;
            var flowchart = (Flowchart)block.GetFlowchart();

            int lastSelectedIndex = -1;
            if (flowchart.SelectedCommands.Count > 0)
            {
                for (int i = 0; i < flowchart.SelectedBlock.CommandList.Count; i++)
                {
                    Command commandInBlock = flowchart.SelectedBlock.CommandList[i];

                    foreach (Command selectedCommand in flowchart.SelectedCommands)
                    {
                        if (commandInBlock == selectedCommand)
                        {
                            lastSelectedIndex = i;
                        }
                    }
                }
            }
            if (lastSelectedIndex < flowchart.SelectedBlock.CommandList.Count - 1)
            {
                flowchart.ClearSelectedCommands();
                flowchart.AddSelectedCommand(flowchart.SelectedBlock.CommandList[lastSelectedIndex + 1]);
            }

            Repaint();
        }
    }
}