using Sandbox;
using Socer;
using System;
using System.Collections.Generic;
using System.Linq;

public sealed partial class FootballWorldPanel
{
    // SceneDynamicObject.Material only passes a native handle to the renderer.
    // The engine's resource cache is weak after its short keepalive expires;
    // own the managed resource for the entire lifetime of our dynamic geometry.
    Material dynamicGeometryMaterial;
    Material DynamicGeometryMaterial=>dynamicGeometryMaterial??=Material.Load("materials/socer/vertex-alpha.vmat");
    ModelRenderer pitchSurface;
    readonly Dictionary<ModelRenderer[],SceneDynamicObject> groundRings=new();
    readonly SceneDynamicObject[] groundPings=new SceneDynamicObject[5];
    readonly Vertex[] ringVertices=new Vertex[32*18];
    int visibleCursorSegments;
    SceneDynamicObject groundLineObject;
    readonly ModelRenderer[] groundLines=new ModelRenderer[36];
    readonly Vertex[] groundLineVertices=new Vertex[36*18];
    int groundLineCount;

    void InitializePitchSurface()
    {
        if(pitchSurface!=null)return;
        if(authoredEnvironment!=null)
        {
            pitchSurface=authoredEnvironment.GameObject.GetComponentsInChildren<ModelRenderer>().FirstOrDefault(r=>r.GameObject.Tags.Has("football-pitch"));
            return;
        }
        // Retire the old ten grass slabs and elevated line boxes on hotload.
        // Corner flags and the foundation are separate geometry and stay intact.
        foreach(var old in RenderScene.GetAllComponents<ModelRenderer>().ToArray())
            if((old.GameObject.Name=="Pitch" && Math.Abs(old.WorldPosition.z+.04f*Units)<.01f) ||
                (old.GameObject.Name=="Geometry" && Math.Abs(old.WorldPosition.z-.025f*Units)<.01f))
                old.GameObject.Destroy();
        Vector3 a=WorldPoint(new Point(-1,-1)),b=WorldPoint(new Point(106,-1));
        Vector3 c=WorldPoint(new Point(106,69)),d=WorldPoint(new Point(-1,69));
        Vertex V(Vector3 p,Vector2 uv)=>new(p,Vector3.Up,Vector3.Forward,uv);
        var vertices=new[]{V(a,new(0,0)),V(c,new(1,1)),V(b,new(1,0)),V(a,new(0,0)),V(d,new(0,1)),V(c,new(1,1))};
        var bounds=new BBox(WorldPoint(new Point(-1,69),-.01f),WorldPoint(new Point(106,-1),.01f));
        var mesh=new Mesh(Material.Load("materials/pitch/turf-markings.vmat"));
        mesh.CreateVertexBuffer(vertices.Length,vertices);mesh.Bounds=bounds;
        pitchSurface=Create(Model.Builder.AddMesh(mesh).WithViewBounds(bounds).Create(),"Textured turf and markings");
        environmentSourceVertices[pitchSurface.Model]=vertices;
    }

    SceneDynamicObject GroundObject()
    {
        // Ship the material and shader with the game; editor tools are absent on clients.
        var obj=new SceneDynamicObject(RenderScene.SceneWorld){Material=DynamicGeometryMaterial};
        obj.Attributes.SetCombo("D_NO_CULLING",1);
        obj.Flags.CastShadows=false;
        return obj;
    }

    float GroundPixelSize(Point center)
    {
        Vector2 a=Project(center),x=Project(center+new Point(.25f,0)),y=Project(center+new Point(0,.25f));
        var sx=new Vector2((x.x-a.x)*Box.Rect.Width,(x.y-a.y)*Box.Rect.Height)*4;
        var sy=new Vector2((y.x-a.x)*Box.Rect.Width,(y.y-a.y)*Box.Rect.Height)*4;
        float aa=sx.LengthSquared,bb=sy.LengthSquared,cross=sx.x*sy.y-sx.y*sy.x;
        float minor=MathF.Sqrt(Math.Max(.01f,(aa+bb-MathF.Sqrt(Math.Max(0,(aa+bb)*(aa+bb)-4*cross*cross)))*.5f));
        return Math.Clamp(1/minor,.005f,.20f);
    }

    void GroundRing(SceneDynamicObject obj,Point center,float radius,float width,string color,int segments,bool visible,float opacity=1)
    {
        obj.RenderingEnabled=visible;
        if(!visible)return;
        // Subpixel solid boxes flicker as camera coverage changes. A flat stroke
        // with a one-pixel alpha fringe stays depth-tested in the turf plane.
        float pixel=GroundPixelSize(center),half=Math.Max(width*.5f,pixel*.52f),feather=pixel*.85f;
        var ink=Ink(color);int count=0;
        float Radius(int band)=>Math.Max(.002f,radius+(band switch {0=>-half-feather,1=>-half,2=>half,_=>half+feather}));
        Vertex V(int segment,int band)
        {
            float angle=segment*MathF.Tau/segments;
            var at=center+new Point(MathF.Cos(angle),MathF.Sin(angle))*Radius(band);
            var tint=new Color32((byte)(ink.r*255),(byte)(ink.g*255),(byte)(ink.b*255),(byte)(band is 0 or 3?0:255*opacity));
            return new Vertex(WorldPoint(at,.012f),tint);
        }
        for(int i=0;i<segments;i++)for(int band=0;band<3;band++)
        {
            var a=V(i,band);var b=V(i+1,band);var c=V(i+1,band+1);var d=V(i,band+1);
            ringVertices[count++]=a;ringVertices[count++]=b;ringVertices[count++]=c;
            ringVertices[count++]=a;ringVertices[count++]=c;ringVertices[count++]=d;
        }
        obj.Init(Graphics.PrimitiveType.Triangles);obj.AddVertex(ringVertices.AsSpan(0,count));
    }

    void GroundLine(ModelRenderer line)
    {
        groundLines[groundLineCount++]=line;line.Enabled=false;
    }
    void DrawGroundLines()
    {
        groundLineObject??=GroundObject();groundLineObject.RenderingEnabled=groundLineCount>0;
        if(groundLineCount==0)return;
        int count=0;
        for(int i=0;i<groundLineCount;i++)
        {
            var line=groundLines[i];var tr=line.WorldTransform;
            var direction=tr.Rotation.Forward;var axis=new Point(direction.x,-direction.y).Unit;
            var at=new Point(tr.Position.x/Units,-tr.Position.y/Units);
            var side=new Point(-axis.Y,axis.X);float pixel=GroundPixelSize(at);
            float half=Math.Max(tr.Scale.y/Units*.5f,pixel*.52f),feather=pixel*.85f;
            var a=at-axis*(tr.Scale.x/Units*.5f);var b=at+axis*(tr.Scale.x/Units*.5f);var ink=line.Tint;
            Vertex V(Point p,int band)
            {
                float offset=band switch {0=>-half-feather,1=>-half,2=>half,_=>half+feather};
                return new Vertex(WorldPoint(p+side*offset,.014f),new Color32((byte)(ink.r*255),(byte)(ink.g*255),(byte)(ink.b*255),(byte)(band is 0 or 3?0:ink.a*255)));
            }
            for(int band=0;band<3;band++)
            {
                var p=V(a,band);var q=V(b,band);var r=V(b,band+1);var s=V(a,band+1);
                groundLineVertices[count++]=p;groundLineVertices[count++]=q;groundLineVertices[count++]=r;
                groundLineVertices[count++]=p;groundLineVertices[count++]=r;groundLineVertices[count++]=s;
            }
        }
        groundLineObject.Init(Graphics.PrimitiveType.Triangles);groundLineObject.AddVertex(groundLineVertices.AsSpan(0,count));
    }
}