using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using UnityEditor.Experimental.UIElements;
using UnityEditor.Experimental.UIElements.GraphView;
using UnityEditor.Graphing.Util;
using UnityEngine;
using UnityEngine.Assertions;
using UnityEngine.Experimental.UIElements;
using UnityEditor.Graphing;
using UnityEditor.ShaderGraph;
using Object = UnityEngine.Object;
using Edge = UnityEditor.Experimental.UIElements.GraphView.Edge;

namespace UnityEditor.ShaderGraph.Drawing
{
    public class MaterialGraphEditWindow : EditorWindow
    {
        [SerializeField]
        string m_Selected;

        [SerializeField]
        SerializableGraphObject m_GraphObject;

        GraphEditorView m_GraphEditorView;

        GraphEditorView graphEditorView
        {
            get { return m_GraphEditorView; }
            set
            {
                if (m_GraphEditorView != null)
                {
                    m_GraphEditorView.RemoveFromHierarchy();
                    m_GraphEditorView.Dispose();
                }
                m_GraphEditorView = value;
                if (m_GraphEditorView != null)
                {
                    m_GraphEditorView.onUpdateAssetClick += UpdateAsset;
                    m_GraphEditorView.onConvertToSubgraphClick += ToSubGraph;
                    m_GraphEditorView.onShowInProjectClick += PingAsset;
                    this.GetRootVisualContainer().Add(graphEditorView);
                }
            }
        }

        SerializableGraphObject graphObject
        {
            get { return m_GraphObject; }
            set
            {
                if (m_GraphObject != null)
                    DestroyImmediate(m_GraphObject);
                m_GraphObject = value;
            }
        }

        public string selectedGuid
        {
            get { return m_Selected; }
            private set { m_Selected = value; }
        }

        void Update()
        {
            if (graphObject == null && selectedGuid != null)
            {
                var guid = selectedGuid;
                selectedGuid = null;
                ChangeSelection(guid);
            }

            if (graphObject == null)
            {
                Close();
                return;
            }

            var materialGraph = graphObject.graph as AbstractMaterialGraph;
            if (materialGraph == null)
                return;
            if (graphEditorView == null)
            {
                var asset = AssetDatabase.LoadAssetAtPath<Object>(AssetDatabase.GUIDToAssetPath(selectedGuid));
                graphEditorView = new GraphEditorView(this, materialGraph, asset.name) { persistenceKey = AssetDatabase.AssetPathToGUID(AssetDatabase.GUIDToAssetPath(selectedGuid)) };
            }

            graphEditorView.HandleGraphChanges();
            graphObject.graph.ClearChanges();
        }

        void OnDisable()
        {
            graphEditorView = null;
        }

        void OnDestroy()
        {
            if (graphObject.isDirty && EditorUtility.DisplayDialog("Shader Graph Might Have Been Modified", "Do you want to save the changes you made in the shader graph?", "Save", "Don't Save"))
                UpdateAsset();
            Undo.ClearUndo(graphObject);
            DestroyImmediate(graphObject);
            graphEditorView = null;
        }

        public void PingAsset()
        {
            if (selectedGuid != null)
            {
                var path = AssetDatabase.GUIDToAssetPath(selectedGuid);
                var asset = AssetDatabase.LoadAssetAtPath<Object>(path);
                EditorGUIUtility.PingObject(asset);
            }
        }

        public void UpdateAsset()
        {
            if (selectedGuid != null && graphObject != null)
            {
                var path = AssetDatabase.GUIDToAssetPath(selectedGuid);
                if (string.IsNullOrEmpty(path) || graphObject == null)
                    return;

                if (m_GraphObject.graph.GetType() == typeof(MaterialGraph))
                    UpdateShaderGraphOnDisk(path);

                if (m_GraphObject.graph.GetType() == typeof(SubGraph))
                    UpdateAbstractSubgraphOnDisk<SubGraph>(path);

                graphObject.isDirty = false;
                var windows = Resources.FindObjectsOfTypeAll<MaterialGraphEditWindow>();
                foreach (var materialGraphEditWindow in windows)
                {
                    materialGraphEditWindow.Rebuild();
                }
            }
        }

        public void ToSubGraph()
        {
            var path = EditorUtility.SaveFilePanelInProject("Save subgraph", "New SubGraph", "ShaderSubGraph", "");
            path = path.Replace(Application.dataPath, "Assets");
            if (path.Length == 0)
                return;

            graphObject.RegisterCompleteObjectUndo("Convert To Subgraph");
            var graphView = graphEditorView.graphView;

            var nodes = graphView.selection.OfType<MaterialNodeView>().Where(x => !(x.node is PropertyNode)).Select(x => x.node as INode).ToArray();
            var bounds = Rect.MinMaxRect(float.PositiveInfinity, float.PositiveInfinity, float.NegativeInfinity, float.NegativeInfinity);
            foreach (var node in nodes)
            {
                var center = node.drawState.position.center;
                bounds = Rect.MinMaxRect(
                        Mathf.Min(bounds.xMin, center.x),
                        Mathf.Min(bounds.yMin, center.y),
                        Mathf.Max(bounds.xMax, center.x),
                        Mathf.Max(bounds.yMax, center.y));
            }
            var middle = bounds.center;
            bounds.center = Vector2.zero;

            var copyPasteGraph = new CopyPasteGraph(
                    graphView.selection.OfType<MaterialNodeView>().Where(x => !(x.node is PropertyNode)).Select(x => x.node as INode),
                    graphView.selection.OfType<Edge>().Select(x => x.userData as IEdge));

            var deserialized = CopyPasteGraph.FromJson(JsonUtility.ToJson(copyPasteGraph, false));
            if (deserialized == null)
                return;

            var subGraph = new SubGraph();
            var subGraphOutputNode = new SubGraphOutputNode();
            {
                var drawState = subGraphOutputNode.drawState;
                drawState.position = new Rect(new Vector2(bounds.xMax + 200f, 0f), drawState.position.size);
                subGraphOutputNode.drawState = drawState;
            }
            subGraph.AddNode(subGraphOutputNode);

            var nodeGuidMap = new Dictionary<Guid, Guid>();
            foreach (var node in deserialized.GetNodes<INode>())
            {
                var oldGuid = node.guid;
                var newGuid = node.RewriteGuid();
                nodeGuidMap[oldGuid] = newGuid;
                var drawState = node.drawState;
                drawState.position = new Rect(drawState.position.position - middle, drawState.position.size);
                node.drawState = drawState;
                subGraph.AddNode(node);
            }

            // figure out what needs remapping
            var externalOutputSlots = new List<IEdge>();
            var externalInputSlots = new List<IEdge>();
            foreach (var edge in deserialized.edges)
            {
                var outputSlot = edge.outputSlot;
                var inputSlot = edge.inputSlot;

                Guid remappedOutputNodeGuid;
                Guid remappedInputNodeGuid;
                var outputSlotExistsInSubgraph = nodeGuidMap.TryGetValue(outputSlot.nodeGuid, out remappedOutputNodeGuid);
                var inputSlotExistsInSubgraph = nodeGuidMap.TryGetValue(inputSlot.nodeGuid, out remappedInputNodeGuid);

                // pasting nice internal links!
                if (outputSlotExistsInSubgraph && inputSlotExistsInSubgraph)
                {
                    var outputSlotRef = new SlotReference(remappedOutputNodeGuid, outputSlot.slotId);
                    var inputSlotRef = new SlotReference(remappedInputNodeGuid, inputSlot.slotId);
                    subGraph.Connect(outputSlotRef, inputSlotRef);
                }
                // one edge needs to go to outside world
                else if (outputSlotExistsInSubgraph)
                {
                    externalInputSlots.Add(edge);
                }
                else if (inputSlotExistsInSubgraph)
                {
                    externalOutputSlots.Add(edge);
                }
            }

            // Find the unique edges coming INTO the graph
            var uniqueIncomingEdges = externalOutputSlots.GroupBy(
                    edge => edge.outputSlot,
                    edge => edge,
                    (key, edges) => new { slotRef = key, edges = edges.ToList() });

            var externalInputNeedingConnection = new List<KeyValuePair<IEdge, IShaderProperty>>();
            foreach (var group in uniqueIncomingEdges)
            {
                var sr = group.slotRef;
                var fromNode = graphObject.graph.GetNodeFromGuid(sr.nodeGuid);
                var fromSlot = fromNode.FindOutputSlot<MaterialSlot>(sr.slotId);

                IShaderProperty prop;
                switch (fromSlot.concreteValueType)
                {
                    case ConcreteSlotValueType.Texture2D:
                        prop = new TextureShaderProperty();
                        break;
                    case ConcreteSlotValueType.Cubemap:
                        prop = new CubemapShaderProperty();
                        break;
                    case ConcreteSlotValueType.Vector4:
                        prop = new Vector4ShaderProperty();
                        break;
                    case ConcreteSlotValueType.Vector3:
                        prop = new Vector3ShaderProperty();
                        break;
                    case ConcreteSlotValueType.Vector2:
                        prop = new Vector2ShaderProperty();
                        break;
                    case ConcreteSlotValueType.Vector1:
                        prop = new FloatShaderProperty();
                        break;
                    default:
                        throw new ArgumentOutOfRangeException();
                }

                if (prop != null)
                {
                    subGraph.AddShaderProperty(prop);
                    var propNode = new PropertyNode();
                    {
                        var drawState = propNode.drawState;
                        drawState.position = new Rect(new Vector2(bounds.xMin - 300f, 0f), drawState.position.size);
                        propNode.drawState = drawState;
                    }
                    subGraph.AddNode(propNode);
                    propNode.propertyGuid = prop.guid;

                    foreach (var edge in group.edges)
                    {
                        subGraph.Connect(
                            new SlotReference(propNode.guid, PropertyNode.OutputSlotId),
                            new SlotReference(nodeGuidMap[edge.inputSlot.nodeGuid], edge.inputSlot.slotId));
                        externalInputNeedingConnection.Add(new KeyValuePair<IEdge, IShaderProperty>(edge, prop));
                    }
                }
            }

            var uniqueOutgoingEdges = externalInputSlots.GroupBy(
                    edge => edge.inputSlot,
                    edge => edge,
                    (key, edges) => new { slot = key, edges = edges.ToList() });

            var externalOutputsNeedingConnection = new List<KeyValuePair<IEdge, IEdge>>();
            foreach (var group in uniqueOutgoingEdges)
            {
                var outputNode = subGraph.outputNode;
                var slotId = outputNode.AddSlot();

                var inputSlotRef = new SlotReference(outputNode.guid, slotId);

                foreach (var edge in group.edges)
                {
                    var newEdge = subGraph.Connect(new SlotReference(nodeGuidMap[edge.outputSlot.nodeGuid], edge.outputSlot.slotId), inputSlotRef);
                    externalOutputsNeedingConnection.Add(new KeyValuePair<IEdge, IEdge>(edge, newEdge));
                }
            }

            File.WriteAllText(path, EditorJsonUtility.ToJson(subGraph));
            AssetDatabase.ImportAsset(path);

            var loadedSubGraph = AssetDatabase.LoadAssetAtPath(path, typeof(MaterialSubGraphAsset)) as MaterialSubGraphAsset;
            if (loadedSubGraph == null)
                return;

            var subGraphNode = new SubGraphNode();
            var ds = subGraphNode.drawState;
            ds.position = new Rect(middle - new Vector2(100f, 150f), Vector2.zero);
            subGraphNode.drawState = ds;
            graphObject.graph.AddNode(subGraphNode);
            subGraphNode.subGraphAsset = loadedSubGraph;

            foreach (var edgeMap in externalInputNeedingConnection)
            {
                graphObject.graph.Connect(edgeMap.Key.outputSlot, new SlotReference(subGraphNode.guid, edgeMap.Value.guid.GetHashCode()));
            }

            foreach (var edgeMap in externalOutputsNeedingConnection)
            {
                graphObject.graph.Connect(new SlotReference(subGraphNode.guid, edgeMap.Value.inputSlot.slotId), edgeMap.Key.inputSlot);
            }

            graphObject.graph.RemoveElements(
                graphView.selection.OfType<MaterialNodeView>().Select(x => x.node as INode),
                Enumerable.Empty<IEdge>());
            graphObject.graph.ValidateGraph();
        }

        void UpdateAbstractSubgraphOnDisk<T>(string path) where T : AbstractSubGraph
        {
            var graph = graphObject.graph as T;
            if (graph == null)
                return;

            File.WriteAllText(path, EditorJsonUtility.ToJson(graph, true));
            AssetDatabase.ImportAsset(path);
        }

        void UpdateShaderGraphOnDisk(string path)
        {
            var graph = graphObject.graph as IShaderGraph;
            if (graph == null)
                return;

            List<PropertyCollector.TextureInfo> configuredTextures;
            graph.GetShader(Path.GetFileNameWithoutExtension(path), GenerationMode.ForReals, out configuredTextures);

            var shaderImporter = AssetImporter.GetAtPath(path) as ShaderGraphImporter;
            if (shaderImporter == null)
                return;

            File.WriteAllText(path, EditorJsonUtility.ToJson(graph, true));
            shaderImporter.SaveAndReimport();
            AssetDatabase.ImportAsset(path);
        }

        private void Rebuild()
        {
            if (graphObject != null && graphObject.graph != null)
            {
                var subNodes = graphObject.graph.GetNodes<AbstractSubGraphNode>();
                foreach (var node in subNodes)
                    node.UpdateSlots();
            }
        }

        public void ChangeSelection(string newSelectionGuid)
        {
            var asset = AssetDatabase.LoadAssetAtPath<Object>(AssetDatabase.GUIDToAssetPath(newSelectionGuid));
            if (asset == null)
                return;

            if (!EditorUtility.IsPersistent(asset))
                return;

            if (selectedGuid == newSelectionGuid)
                return;

            var path = AssetDatabase.GetAssetPath(asset);
            var extension = Path.GetExtension(path);
            Type graphType;
            switch (extension)
            {
                case ".ShaderGraph":
                    graphType = typeof(MaterialGraph);
                    break;
                case ".ShaderSubGraph":
                    graphType = typeof(SubGraph);
                    break;
                default:
                    return;
            }

            selectedGuid = newSelectionGuid;

            var textGraph = File.ReadAllText(path, Encoding.UTF8);
            graphObject = CreateInstance<SerializableGraphObject>();
            graphObject.hideFlags = HideFlags.HideAndDontSave;
            graphObject.graph = JsonUtility.FromJson(textGraph, graphType) as IGraph;
            graphObject.graph.OnEnable();
            graphObject.graph.ValidateGraph();

            graphEditorView = new GraphEditorView(this, m_GraphObject.graph as AbstractMaterialGraph, asset.name) { persistenceKey = AssetDatabase.GUIDToAssetPath(selectedGuid) };
            graphEditorView.RegisterCallback<PostLayoutEvent>(OnPostLayout);

            titleContent = new GUIContent(asset.name);

            Repaint();
        }

        void OnPostLayout(PostLayoutEvent evt)
        {
            graphEditorView.UnregisterCallback<PostLayoutEvent>(OnPostLayout);
            graphEditorView.graphView.FrameAll();
        }
    }
}