using System;
using System.Collections.Generic;
using System.Linq;
using UnityEditor;
using UnityEngine;

namespace XNodeEditor {
    /// <summary> Base class to derive custom Node Graph editors from. Use this to override how graphs are drawn in the editor. </summary>
    [CustomNodeGraphEditor(typeof(XNode.NodeGraph))]
    public class NodeGraphEditor : XNodeEditor.Internal.NodeEditorBase<NodeGraphEditor, NodeGraphEditor.CustomNodeGraphEditorAttribute, XNode.NodeGraph> {
        /// <summary> The position of the window in screen space. </summary>
        public Rect position;
        /// <summary> Are we currently renaming a node? </summary>
        protected bool isRenaming;

        public virtual void OnGUI() { }

        public virtual Texture2D GetGridTexture() {
            return NodeEditorPreferences.GetSettings().gridTexture;
        }

        public virtual Texture2D GetSecondaryGridTexture() {
            return NodeEditorPreferences.GetSettings().crossTexture;
        }

        /// <summary> Return default settings for this graph type. This is the settings the user will load if no previous settings have been saved. </summary>
        public virtual NodeEditorPreferences.Settings GetDefaultPreferences() {
            return new NodeEditorPreferences.Settings();
        }

        /// <summary> Returns context node menu path. Null or empty strings for hidden nodes. </summary>
        public virtual string GetNodeMenuName(Type type) {
            //Check if type has the CreateNodeMenuAttribute
            XNode.Node.CreateNodeMenuAttribute attrib;
            if (NodeEditorUtilities.GetAttrib(type, out attrib)) // Return custom path
                return attrib.menuName;
            else // Return generated path
                return ObjectNames.NicifyVariableName(type.ToString().Replace('.', '/'));
        }

        /// <summary> Add items for the context menu when right-clicking this node. Override to add custom menu items. </summary>
        public virtual void AddContextMenuItems(GenericMenu menu) {
            Vector2 pos = NodeEditorWindow.current.WindowToGridPosition(Event.current.mousePosition);
            for (int i = 0; i < NodeEditorWindow.nodeTypes.Length; i++) {
                Type type = NodeEditorWindow.nodeTypes[i];

                //Get node context menu path
                string path = GetNodeMenuName(type);
                if (string.IsNullOrEmpty(path)) continue;

                menu.AddItem(new GUIContent(path), false, () => {
                    CreateNode(type, pos);
                });
            }
            menu.AddSeparator("");
            menu.AddItem(new GUIContent("Add comment"), false, () => CreateComment(pos));
            menu.AddSeparator("");
            menu.AddItem(new GUIContent("Preferences"), false, () => NodeEditorWindow.OpenPreferences());
            NodeEditorWindow.AddCustomContextMenuItems(menu, target);
        }

        /// <summary> Add items for the context menu when right-clicking this node. Override to add custom menu items. </summary>
        public virtual void AddCommentContextMenuItems(GenericMenu menu) {
            Vector2 pos = NodeEditorWindow.current.WindowToGridPosition(Event.current.mousePosition);
            for (int i = 0; i < NodeEditorWindow.nodeTypes.Length; i++) {
                Type type = NodeEditorWindow.nodeTypes[i];

                //Get node context menu path
                string path = GetNodeMenuName(type);
                if (string.IsNullOrEmpty(path)) continue;

                menu.AddItem(new GUIContent(path), false, () => {
                    CreateNode(type, pos);
                });
            }

            menu.AddSeparator("");
            menu.AddItem(new GUIContent("Add comment"), false, () => CreateComment(pos));
            menu.AddSeparator("");
            // Actions if only one node is selected
            if (Selection.objects.Length == 1 && Selection.activeObject is XNode.NodeGraphComment) {
                XNode.NodeGraphComment comment = Selection.activeObject as XNode.NodeGraphComment;
                menu.AddItem(new GUIContent("Rename"), false, NodeEditorWindow.current.RenameSelectedComment);
            }

            // Add actions to any number of selected nodes
            menu.AddItem(new GUIContent("Duplicate"), false, NodeEditorWindow.current.DuplicateSelectedNodes);
            menu.AddItem(new GUIContent("Remove"), false, NodeEditorWindow.current.RemoveSelectedNodes);
        }

        public virtual Color GetTypeColor(Type type) {
            return NodeEditorPreferences.GetTypeColor(type);
        }

        /// <summary> Create a node and save it in the graph asset </summary>
        public virtual void CreateNode(Type type, Vector2 position) {
            XNode.Node node = target.AddNode(type);
            node.position = position;
            node.name = UnityEditor.ObjectNames.NicifyVariableName(type.Name);
            AssetDatabase.AddObjectToAsset(node, target);
            if (NodeEditorPreferences.GetSettings().autoSave) AssetDatabase.SaveAssets();
            NodeEditorWindow.RepaintAll();
        }

        /// <summary> Creates a copy of the original node in the graph </summary>
        public XNode.Node CopyNode(XNode.Node original) {
            XNode.Node node = target.CopyNode(original);
            node.name = original.name;
            AssetDatabase.AddObjectToAsset(node, target);
            if (NodeEditorPreferences.GetSettings().autoSave) AssetDatabase.SaveAssets();
            return node;
        }

        /// <summary> Safely remove a node and all its connections. </summary>
        public void RemoveNode(XNode.Node node) {
            UnityEngine.Object.DestroyImmediate(node, true);
            target.RemoveNode(node);
            if (NodeEditorPreferences.GetSettings().autoSave) AssetDatabase.SaveAssets();
        }

        /// <summary> Create a comment and save it in the graph asset </summary>
        public void CreateComment(Vector2 position) {
            XNode.NodeGraphComment comment = target.AddComment();
            comment.position = position;
            comment.comment = "New comment";
            AssetDatabase.AddObjectToAsset(comment, target);
            if (NodeEditorPreferences.GetSettings().autoSave) AssetDatabase.SaveAssets();
            NodeEditorWindow.RepaintAll();
        }

        /// <summary> Creates a copy of the original comment in the graph </summary>
        public XNode.NodeGraphComment CopyComment(XNode.NodeGraphComment original) {
            XNode.NodeGraphComment comment = target.CopyComment(original);
            comment.name = original.name;
            AssetDatabase.AddObjectToAsset(comment, target);
            if (NodeEditorPreferences.GetSettings().autoSave) AssetDatabase.SaveAssets();
            return comment;
        }

        /// <summary> Safely remove a comment </summary>
        public void RemoveComment(XNode.NodeGraphComment comment) {
            UnityEngine.Object.DestroyImmediate(comment, true);
            target.RemoveComment(comment);
            if (NodeEditorPreferences.GetSettings().autoSave) AssetDatabase.SaveAssets();
        }

        [AttributeUsage(AttributeTargets.Class)]
        public class CustomNodeGraphEditorAttribute : Attribute,
            XNodeEditor.Internal.NodeEditorBase<NodeGraphEditor, NodeGraphEditor.CustomNodeGraphEditorAttribute, XNode.NodeGraph>.INodeEditorAttrib {
            private Type inspectedType;
            public string editorPrefsKey;
            /// <summary> Tells a NodeGraphEditor which Graph type it is an editor for </summary>
            /// <param name="inspectedType">Type that this editor can edit</param>
            /// <param name="editorPrefsKey">Define unique key for unique layout settings instance</param>
            public CustomNodeGraphEditorAttribute(Type inspectedType, string editorPrefsKey = "xNode.Settings") {
                this.inspectedType = inspectedType;
                this.editorPrefsKey = editorPrefsKey;
            }

            public Type GetInspectedType() {
                return inspectedType;
            }
        }
    }
}