NanoBrain-unitypackage/Editor/DAGWindow.cs

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

namespace NanoBrain {

    // Simple DAG data model
    // [System.Serializable]
    // public class DagNode
    // {
    //     public int id;
    //     public string title;
    //     public Vector2 position;
    //     public float radius = 36f; // circle radius
    // }

    // [System.Serializable]
    // public class DagEdge
    // {
    //     public int fromId;
    //     public int toId;
    // }

    public class DAGEditorWindow : EditorWindow {
        List<DagNode> nodes = new List<DagNode>();
        List<DagEdge> edges = new List<DagEdge>();

        Vector2 pan = Vector2.zero;
        float zoom = 1.0f;
        const float minZoom = 0.5f;
        const float maxZoom = 2.0f;

        GUIStyle labelStyle;
        int selectedNodeId = -1;

        Vector2 dragStart;
        bool draggingNode = false;
        int draggingNodeId = -1;

        [MenuItem("Window/DAG Viewer (LR, Circles)")]
        public static void ShowWindow() {
            var w = GetWindow<DAGEditorWindow>("DAG Viewer (LR)");
            w.minSize = new Vector2(500, 300);
        }

        void OnEnable() {
            labelStyle = new GUIStyle(EditorStyles.label);
            labelStyle.alignment = TextAnchor.MiddleCenter;
            labelStyle.normal.textColor = Color.white;
            labelStyle.fontStyle = FontStyle.Bold;

            if (nodes.Count == 0)
                CreateSampleGraph();

            ComputeLeftToRightLayout();
        }

        void CreateSampleGraph() {
            nodes.Clear();
            edges.Clear();

            nodes.Add(new DagNode() { id = 0, title = "In1" });
            nodes.Add(new DagNode() { id = 1, title = "In2" });
            nodes.Add(new DagNode() { id = 2, title = "A" });
            nodes.Add(new DagNode() { id = 3, title = "B" });
            nodes.Add(new DagNode() { id = 4, title = "C" });
            nodes.Add(new DagNode() { id = 5, title = "Out1" });
            nodes.Add(new DagNode() { id = 6, title = "Out2" });

            edges.Add(new DagEdge() { fromId = 0, toId = 2 });
            edges.Add(new DagEdge() { fromId = 1, toId = 2 });
            edges.Add(new DagEdge() { fromId = 2, toId = 3 });
            edges.Add(new DagEdge() { fromId = 2, toId = 4 });
            edges.Add(new DagEdge() { fromId = 3, toId = 5 });
            edges.Add(new DagEdge() { fromId = 4, toId = 6 });
        }

        void OnGUI() {
            HandleInput();

            Rect rect = new Rect(0, 0, position.width, position.height);
            EditorGUI.DrawRect(rect, new Color(0.11f, 0.11f, 0.11f));

            Matrix4x4 oldMatrix = GUI.matrix;
            Vector2 origin = new Vector2(position.width / 2, position.height / 2);
            GUI.matrix = Matrix4x4.TRS(origin + pan, Quaternion.identity, Vector3.one * zoom) *
                         Matrix4x4.TRS(-origin, Quaternion.identity, Vector3.one);

            // Draw edges first
            foreach (var e in edges) {
                var from = GetNodeById(e.fromId);
                var to = GetNodeById(e.toId);
                if (from == null || to == null) continue;
                DrawEdgeCircleNodes(from, to);
            }

            // Draw nodes (circles)
            foreach (var n in nodes) {
                DrawNodeCircle(n);
            }

            GUI.matrix = oldMatrix;

            // Footer toolbar
            GUILayout.FlexibleSpace();
            EditorGUILayout.BeginHorizontal(EditorStyles.toolbar);
            if (GUILayout.Button("Fit", EditorStyles.toolbarButton)) FitToView();
            if (GUILayout.Button("Layout LR", EditorStyles.toolbarButton)) ComputeLeftToRightLayout();
            if (GUILayout.Button("Add Node", EditorStyles.toolbarButton)) {
                AddNode("N" + nodes.Count);
                ComputeLeftToRightLayout();
            }
            if (GUILayout.Button("Add Edge (selected->new)", EditorStyles.toolbarButton)) {
                if (selectedNodeId != -1) {
                    var newNode = AddNode("N" + nodes.Count);
                    edges.Add(new DagEdge() { fromId = selectedNodeId, toId = newNode.id });
                    ComputeLeftToRightLayout();
                }
            }
            EditorGUILayout.EndHorizontal();
        }

        void HandleInput() {
            Event e = Event.current;

            // Zoom with scroll
            if (e.type == EventType.ScrollWheel) {
                float oldZoom = zoom;
                float delta = -e.delta.y * 0.01f;
                zoom = Mathf.Clamp(zoom + delta, minZoom, maxZoom);
                Vector2 mouse = e.mousePosition;
                pan += (mouse - new Vector2(position.width / 2, position.height / 2)) * (1 - zoom / oldZoom);
                e.Use();
            }

            // Pan with middle or right+ctrl drag
            if (e.type == EventType.MouseDrag && (e.button == 2 || (e.button == 1 && e.control))) {
                pan += e.delta;
                e.Use();
            }

            // Node dragging & selection (convert mouse to graph space)
            Vector2 graphMouse = ScreenToGraph(e.mousePosition);
            if (e.type == EventType.MouseDown && e.button == 0) {
                int hit = HitTestNode(graphMouse);
                if (hit != -1) {
                    selectedNodeId = hit;
                    draggingNode = true;
                    draggingNodeId = hit;
                    dragStart = graphMouse;
                    e.Use();
                }
                else {
                    selectedNodeId = -1;
                }
            }

            if (draggingNode && draggingNodeId != -1) {
                if (e.type == EventType.MouseDrag && e.button == 0) {
                    Vector2 graphDelta = e.delta / zoom;
                    var n = GetNodeById(draggingNodeId);
                    if (n != null) {
                        n.position += graphDelta;
                        Repaint();
                        e.Use();
                    }
                }
                if (e.type == EventType.MouseUp && e.button == 0) {
                    draggingNode = false;
                    draggingNodeId = -1;
                    e.Use();
                }
            }
        }

        DagNode AddNode(string title) {
            int nextId = nodes.Count > 0 ? nodes.Max(n => n.id) + 1 : 0;
            var n = new DagNode() { id = nextId, title = title, position = Vector2.zero };
            nodes.Add(n);
            return n;
        }

        DagNode GetNodeById(int id) => nodes.FirstOrDefault(x => x.id == id);

        void DrawNodeCircle(DagNode n) {
            Vector2 center = n.position;
            float r = n.radius;
            Rect nodeRect = new Rect(center.x - r, center.y - r, r * 2, r * 2);

            // circle background
            Color bg = (n.id == selectedNodeId) ? new Color(0.15f, 0.5f, 0.9f) : new Color(0.2f, 0.2f, 0.2f);
            EditorGUI.DrawRect(nodeRect, bg);

            // anti-aliased circle outline
            Handles.color = Color.white * 0.9f;
            Handles.DrawAAPolyLine(3f / zoom, GetCircleOutlinePoints(center, r, 48).ToArray());

            // label
            Vector2 labelPos = center - new Vector2(0, 8);
            GUI.Label(new Rect(labelPos.x - r, labelPos.y - 8, r * 2, 18), n.title, labelStyle);
        }

        List<Vector3> GetCircleOutlinePoints(Vector2 center, float radius, int segments) {
            var pts = new List<Vector3>(segments + 1);
            for (int i = 0; i <= segments; i++) {
                float a = (float)i / segments * Mathf.PI * 2f;
                pts.Add(new Vector3(center.x + Mathf.Cos(a) * radius, center.y + Mathf.Sin(a) * radius, 0));
            }
            return pts;
        }

        void DrawEdgeCircleNodes(DagNode from, DagNode to) {
            Vector2 a = from.position;
            Vector2 b = to.position;
            if (a == b) return;

            // Compute edge line that starts/ends at circle circumferences
            Vector2 dir = (b - a).normalized;
            Vector2 start = a + dir * from.radius;
            Vector2 end = b - dir * to.radius;

            // Use a simple curved line: start -> control -> end (bezier)
            Vector2 control = new Vector2((start.x + end.x) / 2f, (start.y + end.y) / 2f);
            // Slight vertical offset to separate overlapping lines based on node ids
            float offset = ((from.id * 7 + to.id * 11) % 7 - 3) * 6f / zoom;
            control += new Vector2(0, offset);

            Handles.color = Color.white * 0.9f;
            Handles.DrawAAPolyLine(3f / zoom, 20, GetBezierPoints(start, control, end, 24).ToArray());

            // Arrow at end pointing towards 'b'
            DrawArrowHead(end - dir * 2f, end, 10f / zoom, 12f / zoom, Color.white);
        }

        List<Vector3> GetBezierPoints(Vector2 p0, Vector2 p1, Vector2 p2, int seg) {
            var pts = new List<Vector3>(seg + 1);
            for (int i = 0; i <= seg; i++) {
                float t = (float)i / seg;
                Vector2 p = (1 - t) * (1 - t) * p0 + 2 * (1 - t) * t * p1 + t * t * p2;
                pts.Add(new Vector3(p.x, p.y, 0));
            }
            return pts;
        }

        void DrawArrowHead(Vector2 from, Vector2 to, float headWidth, float headLength, Color color) {
            Vector2 dir = (to - from).normalized;
            if (dir == Vector2.zero) return;
            Vector2 right = new Vector2(-dir.y, dir.x);

            Vector3 p1 = to;
            Vector3 p2 = to - dir * headLength + right * headWidth * 0.5f;
            Vector3 p3 = to - dir * headLength - right * headWidth * 0.5f;

            Handles.color = color;
            Handles.DrawAAConvexPolygon(p1, p2, p3);
        }

        // Left-to-right layered layout (sources on the left, sinks on the right)
        void ComputeLeftToRightLayout() {
            // build adjacency and indegree
            var adj = nodes.ToDictionary(n => n.id, n => new List<int>());
            var indeg = nodes.ToDictionary(n => n.id, n => 0);
            foreach (var e in edges) {
                if (!adj.ContainsKey(e.fromId) || !adj.ContainsKey(e.toId)) continue;
                adj[e.fromId].Add(e.toId);
                indeg[e.toId]++;
            }

            // Kahn's algorithm to compute topological layers (horizontal layers)
            Dictionary<int, int> layer = new Dictionary<int, int>();
            Queue<int> q = new Queue<int>(indeg.Where(kv => kv.Value == 0).Select(kv => kv.Key));
            foreach (var id in q) layer[id] = 0;

            while (q.Count > 0) {
                int u = q.Dequeue();
                int l = layer[u];
                foreach (var v in adj[u]) {
                    // prefer placing v at least one layer after u
                    if (!layer.ContainsKey(v) || layer[v] < l + 1) layer[v] = l + 1;
                    indeg[v]--;
                    if (indeg[v] == 0) q.Enqueue(v);
                }
            }

            // Any unreachable nodes -> assign next layers
            int maxLayer = layer.Count > 0 ? layer.Values.Max() : 0;
            foreach (var n in nodes) {
                if (!layer.ContainsKey(n.id)) {
                    maxLayer++;
                    layer[n.id] = maxLayer;
                }
            }

            // Group nodes by layer (left to right)
            var layers = layer.GroupBy(kv => kv.Value).OrderBy(g => g.Key).Select(g => g.Select(x => x.Key).ToList()).ToList();

            // Layout parameters (horizontal spacing drives left->right)
            float hSpacing = 220f;
            float vSpacing = 120f;

            // Place nodes: x increases with layer index, y spaced within layer
            for (int li = 0; li < layers.Count; li++) {
                var lst = layers[li];
                float totalHeight = (lst.Count - 1) * vSpacing;
                for (int i = 0; i < lst.Count; i++) {
                    int id = lst[i];
                    var n = GetNodeById(id);
                    if (n == null) continue;
                    float x = li * hSpacing;
                    float y = -totalHeight / 2f + i * vSpacing;
                    n.position = new Vector2(x, y);
                }
            }

            Repaint();
        }

        void FitToView() {
            if (nodes.Count == 0) return;
            Rect bounds = new Rect(nodes[0].position - Vector2.one * nodes[0].radius, Vector2.one * nodes[0].radius * 2f);
            foreach (var n in nodes)
                bounds = RectUnion(bounds, new Rect(n.position - Vector2.one * n.radius, Vector2.one * n.radius * 2f));

            Vector2 center = bounds.center;
            pan = -center;
            zoom = 1.0f;
            Repaint();
        }

        static Rect RectUnion(Rect a, Rect b) {
            float xMin = Mathf.Min(a.xMin, b.xMin);
            float xMax = Mathf.Max(a.xMax, b.xMax);
            float yMin = Mathf.Min(a.yMin, b.yMin);
            float yMax = Mathf.Max(a.yMax, b.yMax);
            return Rect.MinMaxRect(xMin, yMin, xMax, yMax);
        }

        Vector2 ScreenToGraph(Vector2 screenPos) {
            Vector2 origin = new Vector2(position.width / 2, position.height / 2);
            // invert the GUI.matrix transform (approx for current simple transforms)
            return (screenPos - (origin + pan)) / zoom + origin * (1 - 1 / zoom);
        }

        int HitTestNode(Vector2 graphPos) {
            // returns node id under point or -1
            for (int i = nodes.Count - 1; i >= 0; i--) {
                var n = nodes[i];
                if ((graphPos - n.position).sqrMagnitude <= n.radius * n.radius) return n.id;
            }
            return -1;
        }
    }

}