using System;
using System.Collections.Generic;
using System.Dynamic;
using Unity.VisualScripting;
using UnityEditor;
using UnityEngine;
using UnityEngine.Rendering;
using UnityEngine.UIElements;
using static UnityEngine.GraphicsBuffer;

[ExecuteAlways]
public class GameManager : MonoBehaviour
{
    [HideInInspector]
    public static GameManager instance;

    public Transform NodeParent;
    public GameObject NodePrefab;


    [Header("Node Generation")]

    [Range(0, 20)]
    public float maxConnectionLength = 6;

    [Range(0, 1000)]
    public int nodeCount = 100;

    [Range(0, 100)]
    public float hoverRadius = 50;

    [Space]
    [Range(0,10)]
    public int editorConnectionAllowedWidth = 3;
    public Color editorConnectionAllowedColor = Color.white;

    [Space]
    [Range(0, 10)]
    public int editorConnectionHoveredWidth = 2;
    public Color editorConnectionHoveredColor = Color.gray;

    [Space]
    [Range(0,10)]
    public int editorConnectionForbiddenWidth = 1;
    public Color editorConnectionForbiddenColor = Color.black;


    private List<Node> nodes = new List<Node>();

    [SerializeField]
    public List<Connection> connections = new List<Connection>();

    [Serializable]
    public class Connection
    {
        public Node nodeA, nodeB;
        public bool allowed;
        public LineRenderer lineRenderer;

        ~Connection()
        {
            DestroyImmediate(lineRenderer.transform.parent);
        }
    }

    public void GenerateAlongSphere()
    {
        connections.Clear();
        nodes.Clear();

        for (int i = NodeParent.childCount - 1; i >= 0; i--)
            DestroyImmediate(NodeParent.GetChild(i).gameObject);

        float radius = 20f;
        float goldenRatio = (1f + Mathf.Sqrt(5f)) / 2f;
        float angleIncrement = 2f * Mathf.PI * goldenRatio;

        for (int i = 0; i < nodeCount; i++)
        {
            float t = (float)i / nodeCount; // von 0 bis 1
            float inclination = Mathf.Acos(1f - 2f * t);
            float azimuth = angleIncrement * i;

            float x = Mathf.Sin(inclination) * Mathf.Cos(azimuth);
            float y = Mathf.Sin(inclination) * Mathf.Sin(azimuth);
            float z = Mathf.Cos(inclination);

            Vector3 pos = new Vector3(x, y, z) * radius;

            var auto = PrefabUtility.InstantiatePrefab(NodePrefab, NodeParent) as GameObject;
            auto.transform.localPosition = pos;
            nodes.Add(auto.GetComponent<Node>());
        }
    }

    public void GenerateConnections()
    {
        connections.Clear();
         
        foreach (Node nodeA in nodes)
        {
            if (nodeA == null) continue;
            foreach (Node nodeB in nodes)
            {
                if (nodeB == null) continue;
                bool conExists = false;
                if (nodeA == nodeB || Math.Abs(Vector3.Distance(nodeA.transform.position, nodeB.transform.position)) > maxConnectionLength)
                    continue;

                foreach (Connection con in connections)
                {
                    if ((con.nodeA == nodeA && con.nodeB == nodeB) || (con.nodeA == nodeB && con.nodeB == nodeA))
                    {
                        conExists = true;
                        break;
                    }
                }
                if (!conExists)
                {
                    var dummy = Instantiate(new GameObject(), transform);
                    dummy.name = "Dummy";
                    var newCon = new Connection
                    {
                        nodeA = nodeA,
                        nodeB = nodeB,
                        lineRenderer = dummy.AddComponent<LineRenderer>()
                    };

                    newCon.lineRenderer.enabled = false;
                    newCon.lineRenderer.material = new Material(Shader.Find("Sprites/Default"));
                    newCon.lineRenderer.positionCount = 3;

                    connections.Add(newCon);
                }
            }
                   
        }
    }

    #if UNITY_EDITOR
    void OnDrawGizmos()
    {
        if (connections == null) return;

        // Linien respektieren den Z-Buffer
        Handles.zTest = UnityEngine.Rendering.CompareFunction.LessEqual;

        foreach (var con in connections)
        {
            if(!con.allowed) continue;
            Handles.color = Color.red;
            Handles.DrawLine(con.nodeA.transform.position, con.nodeB.transform.position);
        }
    }
#endif

    private void Update()
    {
        foreach (var con in connections)
        {
            if (!con.allowed)
            {
                con.lineRenderer.enabled = false;
                continue;
            }
            con.lineRenderer.enabled = true;
            con.lineRenderer.startColor = con.nodeA.transform.GetChild(0).GetComponent<Renderer>().material.color;
            con.lineRenderer.endColor = con.nodeB.transform.GetChild(0).GetComponent<Renderer>().material.color;
            con.lineRenderer.startWidth = 0.3f;
            con.lineRenderer.endWidth = 0.3f;

            con.lineRenderer.SetGreatCircleArc(con.nodeA.transform.position, con.nodeB.transform.position, 5, 20.5f);
            con.lineRenderer.enabled = true;
        }
    }
}

#if UNITY_EDITOR
[CustomEditor(typeof(GameManager))]
public class GameManagerEditor : Editor
{
    int clickedConIdx = -1;

    public override void OnInspectorGUI()
    { 
        DrawDefaultInspector(); 

        GameManager gm = (GameManager)target; 
        GUILayout.BeginHorizontal(); 

        if (GUILayout.Button("Generate Sphere"))         
            gm.GenerateAlongSphere(); 
        
        if (GUILayout.Button("Generate Connections"))         
            gm.GenerateConnections();  
        
        GUILayout.EndHorizontal(); 
        
        if (GUILayout.Button("Generate")) 
        {
            gm.GenerateAlongSphere(); 
            gm.GenerateConnections(); 
        }
    }
    private void OnSceneGUI()
    {
        Handles.zTest = UnityEngine.Rendering.CompareFunction.LessEqual;

        GameManager gm = (GameManager)target;
        if (gm.connections == null || gm.connections.Count == 0) return;
        Camera cam = SceneView.lastActiveSceneView.camera;
        if (cam == null) return;

        Vector2 mouse = Event.current.mousePosition;
        mouse.y = cam.pixelHeight - mouse.y;
        Vector3 mousePos = new Vector3(mouse.x, mouse.y, 0);

        int closestIdx = -1;
        float closestDist = float.MaxValue;

        // Hover-Ermittlung
        for (int i = 0; i < gm.connections.Count; i++)
        {
            var con = gm.connections[i];
            Vector3 a = cam.WorldToScreenPoint(con.nodeA.transform.position);
            Vector3 b = cam.WorldToScreenPoint(con.nodeB.transform.position);

            Vector3 ab = b - a;
            Vector3 am = mousePos - a;
            float t = Mathf.Clamp01(Vector3.Dot(am, ab) / ab.sqrMagnitude);
            Vector3 proj = a + t * ab;
            float dist = Vector3.Distance(mousePos, proj);

            if (dist < closestDist && dist < gm.hoverRadius)
            {
                closestDist = dist;
                closestIdx = i;
            }
        }

        // Klick-Behandlung
        Event e = Event.current;
        if (e.type == EventType.MouseDown && e.button == 0 && closestIdx >= 0) 
        {
            clickedConIdx = closestIdx;
        }

        if (e.type == EventType.MouseUp && e.button == 0)
        {
            if (closestIdx == clickedConIdx && closestIdx != -1)
            {
                gm.connections[closestIdx].allowed = !gm.connections[closestIdx].allowed;
                e.Use(); // Event als verarbeitet markieren
            }

            clickedConIdx = -1;
        }

        // Zeichnen
        for (int i = 0; i < gm.connections.Count; i++)
        {
            var con = gm.connections[i];
            Handles.color = (i == closestIdx && !con.allowed) ? gm.editorConnectionHoveredColor : con.allowed ? gm.editorConnectionAllowedColor : gm.editorConnectionForbiddenColor;
            float thickness = (i == closestIdx) ? gm.editorConnectionHoveredWidth : con.allowed ? gm.editorConnectionAllowedWidth : gm.editorConnectionForbiddenWidth;
            Handles.DrawLine(con.nodeA.transform.position, con.nodeB.transform.position, thickness);
        }

        // SceneView kontinuierlich aktualisieren
        SceneView.RepaintAll();
    }
}
#endif


public static class LineRendererExtensions
{
    // Zeichnet eine Quadratic Bezier Kurve (Start, Control, End) mit N Punkten
    public static void SetQuadraticBezier(this LineRenderer line, Vector3 start, Vector3 control, Vector3 end, int segments)
    {
        line.positionCount = segments + 1;

        for (int i = 0; i <= segments; i++)
        {
            float t = i / (float)segments;
            // Quadratic Bezier Formel
            Vector3 point = (1 - t) * (1 - t) * start +
                            2 * (1 - t) * t * control +
                            t * t * end;

            line.SetPosition(i, point);
        }
    }

    public static void SetGreatCircleArc(this LineRenderer line, Vector3 start, Vector3 end, int segments, float radius)
    {
        // Normalize to sphere radius
        Vector3 startNorm = start.normalized * radius;
        Vector3 endNorm = end.normalized * radius;

        line.positionCount = segments + 1;

        for (int i = 0; i <= segments; i++)
        {
            float t = i / (float)segments;
            // spherical linear interpolation (slerp) between start and end
            Vector3 point = Vector3.Slerp(startNorm, endNorm, t);
            line.SetPosition(i, point);
        }
    }
}