using System;
using System.Linq;
using System.Reflection;
using UnityEditor;
using UnityEngine;
using XNode;

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> {
        [Obsolete("Use window.position instead")]
        public Rect position { get { return window.position; } set { window.position = value; } }
        /// <summary> Are we currently renaming a node? </summary>
        protected bool isRenaming;

        public virtual void OnGUI() { }

        /// <summary> Called when opened by NodeEditorWindow </summary>
        public virtual void OnOpen() { }

        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 NodeEditorUtilities.NodeDefaultPath(type);
        }

        /// <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 < NodeEditorReflection.nodeTypes.Length; i++) {
                Type type = NodeEditorReflection.nodeTypes[i];

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

                menu.AddItem(new GUIContent(path), false, () => {
                    XNode.Node node = CreateNode(type, pos);
                    NodeEditorWindow.current.AutoConnect(node);
                });
            }
            menu.AddSeparator("");
            if (NodeEditorWindow.copyBuffer != null && NodeEditorWindow.copyBuffer.Length > 0) menu.AddItem(new GUIContent("Paste"), false, () => NodeEditorWindow.current.PasteNodes(pos));
            else menu.AddDisabledItem(new GUIContent("Paste"));
            menu.AddItem(new GUIContent("Preferences"), false, () => NodeEditorReflection.OpenPreferences());
            menu.AddCustomContextMenuItems(target);
        }

        /// <summary> Returned gradient is used to color noodles </summary>
        /// <param name="output"> The output this noodle comes from. Never null. </param>
        /// <param name="input"> The output this noodle comes from. Can be null if we are dragging the noodle. </param>
        public virtual Gradient GetNoodleGradient(XNode.NodePort output, XNode.NodePort input) {
            Gradient grad = new Gradient();

            // If dragging the noodle, draw solid, slightly transparent
            if (input == null) {
                Color a = GetTypeColor(output.ValueType);
                grad.SetKeys(
                    new GradientColorKey[] { new GradientColorKey(a, 0f) },
                    new GradientAlphaKey[] { new GradientAlphaKey(0.6f, 0f) }
                );
            }
            // If normal, draw gradient fading from one input color to the other
            else {
                Color a = GetTypeColor(output.ValueType);
                Color b = GetTypeColor(input.ValueType);
                // If any port is hovered, tint white
                if (window.hoveredPort == output || window.hoveredPort == input) {
                    a = Color.Lerp(a, Color.white, 0.8f);
                    b = Color.Lerp(b, Color.white, 0.8f);
                }
                grad.SetKeys(
                    new GradientColorKey[] { new GradientColorKey(a, 0f), new GradientColorKey(b, 1f) },
                    new GradientAlphaKey[] { new GradientAlphaKey(1f, 0f), new GradientAlphaKey(1f, 1f) }
                );
            }
            return grad;
        }

        /// <summary> Returned float is used for noodle thickness </summary>
        /// <param name="output"> The output this noodle comes from. Never null. </param>
        /// <param name="input"> The output this noodle comes from. Can be null if we are dragging the noodle. </param>
        public virtual float GetNoodleThickness(XNode.NodePort output, XNode.NodePort input) {
            return 5f;
        }

        public virtual NoodlePath GetNoodlePath(XNode.NodePort output, XNode.NodePort input) {
            return NodeEditorPreferences.GetSettings().noodlePath;
        }

        public virtual NoodleStroke GetNoodleStroke(XNode.NodePort output, XNode.NodePort input) {
            return NodeEditorPreferences.GetSettings().noodleStroke;
        }

        /// <summary> Returned color is used to color ports </summary>
        public virtual Color GetPortColor(XNode.NodePort port) {
            return GetTypeColor(port.ValueType);
        }

        /// <summary> Returns generated color for a type. This color is editable in preferences </summary>
        public virtual Color GetTypeColor(Type type) {
            return NodeEditorPreferences.GetTypeColor(type);
        }

        /// <summary> Override to display custom tooltips </summary>
        public virtual string GetPortTooltip(XNode.NodePort port) {
            // Allow tooltips to be overridden or to have their values hidden based on attribute usage
            // First, a port managed by a DynamicPortList will have a fieldName of "realName X", so we won't find it directly.
            FieldInfo portFieldInfo = null;
            string[] fieldNameParts = port.fieldName.Split(' ');
            if (port.IsDynamic && fieldNameParts.Length == 2) {
                portFieldInfo = port.node.GetType().GetField(fieldNameParts[0]);
            }
            // If a port isn't dynamic, doesn't match the format, or we didn't find its field, try getting it directly
            if (portFieldInfo == null) {
                portFieldInfo = port.node.GetType().GetField(port.fieldName);
            }
            
            // If the fieldInfo is still null, abort mission; otherwise, look for our attribute.
            OverrideTooltipAttribute attr = null;
            if (portFieldInfo != null) {
                attr = ((OverrideTooltipAttribute[])portFieldInfo
                    .GetCustomAttributes(typeof(OverrideTooltipAttribute), false)).SingleOrDefault();
            }
            string tooltip = attr != null && attr.overrideTooltip ? attr.tooltip : port.ValueType.PrettyName();
            bool hideValue = attr != null && attr.hideValue;
            // ReSharper disable once InvertIf
            if (!hideValue && port.IsOutput) {
                var obj = port.node.GetValue(port);
                tooltip += " = " + (obj != null ? obj.ToString() : "null");
            }
            return tooltip;
        }

        /// <summary> Deal with objects dropped into the graph through DragAndDrop </summary>
        public virtual void OnDropObjects(UnityEngine.Object[] objects) {
            Debug.Log("No OnDropObjects override defined for " + GetType());
        }

        /// <summary> Create a node and save it in the graph asset </summary>
        public virtual XNode.Node CreateNode(Type type, Vector2 position) {
            Undo.RecordObject(target, "Create Node");
            XNode.Node node = target.AddNode(type);
            Undo.RegisterCreatedObjectUndo(node, "Create Node");
            node.position = position;
            if (node.name == null || node.name.Trim() == "") node.name = NodeEditorUtilities.NodeDefaultName(type);
            AssetDatabase.AddObjectToAsset(node, target);
            if (NodeEditorPreferences.GetSettings().autoSave) AssetDatabase.SaveAssets();
            NodeEditorWindow.RepaintAll();
            return node;
        }

        /// <summary> Creates a copy of the original node in the graph </summary>
        public XNode.Node CopyNode(XNode.Node original) {
            Undo.RecordObject(target, "Duplicate Node");
            XNode.Node node = target.CopyNode(original);
            Undo.RegisterCreatedObjectUndo(node, "Duplicate Node");
            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 virtual void RemoveNode(XNode.Node node) {
            Undo.RecordObject(node, "Delete Node");
            Undo.RecordObject(target, "Delete Node");
            foreach (var port in node.Ports)
                foreach (var conn in port.GetConnections())
                    Undo.RecordObject(conn.node, "Delete Node");
            target.RemoveNode(node);
            Undo.DestroyObjectImmediate(node);
            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;
            }
        }
    }
}