using System;
using UnityEngine;

namespace Rigging.Debugging
{

    public class DebugRigidBody : MonoBehaviour
    {

        public enum EMode
        {
            Axis,
            Cube,
            Axis_Cube,
            Custom,
        }
        public EMode mode = EMode.Axis;

        public Color color = Color.white;

        // When added to an object, draws colored rays from the
        // transform position.
        public int lineCount = 100;
        public float radius = 3.0f;

        public float cubeLen = 0.05f;

        public System.Action customDraw;

        static Material lineMaterial;
        static void CreateLineMaterial()
        {
            if (!lineMaterial)
            {
                // Unity has a built-in shader that is useful for drawing
                // simple colored things.
                Shader shader = Shader.Find("Hidden/Internal-Colored");
                lineMaterial = new Material(shader);
                lineMaterial.hideFlags = HideFlags.HideAndDontSave;
                // Turn on alpha blending
                lineMaterial.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.SrcAlpha);
                lineMaterial.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.OneMinusSrcAlpha);
                // Turn backface culling off
                lineMaterial.SetInt("_Cull", (int)UnityEngine.Rendering.CullMode.Off);
                // Turn off depth writes
                lineMaterial.SetInt("_ZWrite", 0);
            }
        }

        private void PutVertex(Vector3 vert)
        {
            GL.Vertex3(vert.x, vert.y, vert.z);
        }

        // Will be called after all regular rendering is done
        public void OnRenderObject()
        {
            CreateLineMaterial();
            // Apply the line material
            lineMaterial.SetPass(0);

            if (mode == EMode.Axis || mode == EMode.Axis_Cube)
            {
                GL.PushMatrix();
                // Set transformation matrix for drawing to
                // match our transform
                GL.MultMatrix(transform.localToWorldMatrix);

                // Draw lines
                GL.Begin(GL.LINES);

                float len = 0.3f;

                GL.Color(Color.red);
                PutVertex(Vector3.zero);
                PutVertex(Vector3.right * len);

                GL.Color(Color.green);
                PutVertex(Vector3.zero);
                PutVertex(Vector3.up * len);

                GL.Color(Color.blue);
                PutVertex(Vector3.zero);
                PutVertex(Vector3.forward * len);

                GL.End();
                GL.PopMatrix();
            }
            if (mode == EMode.Cube || mode == EMode.Axis_Cube)
            {
                GL.PushMatrix();
                // Set transformation matrix for drawing to
                // match our transform
                GL.MultMatrix(transform.localToWorldMatrix);

                float len = cubeLen / 2.0f;

                GL.wireframe = true;

                GL.Begin(GL.QUADS);

                GL.Color(color);

                GL.Vertex3(len, len, -len);
                GL.Vertex3(-len, len, -len);
                GL.Vertex3(-len, len, len);
                GL.Vertex3(len, len, len);

                // Bottom face (y = -len)
                GL.Vertex3(len, -len, len);
                GL.Vertex3(-len, -len, len);
                GL.Vertex3(-len, -len, -len);
                GL.Vertex3(len, -len, -len);

                // Front face  (z = len)
                GL.Vertex3(len, len, len);
                GL.Vertex3(-len, len, len);
                GL.Vertex3(-len, -len, len);
                GL.Vertex3(len, -len, len);

                // Back face (z = -len)
                GL.Vertex3(len, -len, -len);
                GL.Vertex3(-len, -len, -len);
                GL.Vertex3(-len, len, -len);
                GL.Vertex3(len, len, -len);

                // Left face (x = -len)
                GL.Vertex3(-len, len, len);
                GL.Vertex3(-len, len, -len);
                GL.Vertex3(-len, -len, -len);
                GL.Vertex3(-len, -len, len);

                // Right face (x = len)
                GL.Vertex3(len, len, -len);
                GL.Vertex3(len, len, len);
                GL.Vertex3(len, -len, len);
                GL.Vertex3(len, -len, -len);
                GL.End();  // End of drawing color-cube

                GL.wireframe = false;

                GL.PopMatrix();
            }
            if (mode == EMode.Custom)
            {
                if (customDraw != null)
                {
                    customDraw.Invoke();
                }
            }
        }

    }

}