using OpenTK.Graphics.OpenGL4;
using OpenTK.Mathematics;

namespace Voxel
{
    public class Shader
    {
        private int _handle;
        private bool disposedValue = false;

        public Shader(string vertexPath, string fragmentPath)
        {
            string vertexShaderSource = File.ReadAllText(vertexPath);
            string fragmentShaderSource = File.ReadAllText(fragmentPath);

            int vertexShader = GL.CreateShader(ShaderType.VertexShader);
            int fragmentShader = GL.CreateShader(ShaderType.FragmentShader);

            GL.ShaderSource(vertexShader, vertexShaderSource);
            GL.ShaderSource(fragmentShader, fragmentShaderSource);

            GL.CompileShader(vertexShader);
            GL.GetShader(vertexShader, ShaderParameter.CompileStatus, out int success);
            if (success == 0)
            {
                string infoLog = GL.GetShaderInfoLog(vertexShader);
                Console.WriteLine(infoLog);
            }

            GL.CompileShader(fragmentShader);
            if (success == 0)
            {
                string infoLog = GL.GetShaderInfoLog(fragmentShader);
                Console.WriteLine(infoLog);
            }

            // attach

            _handle = GL.CreateProgram();

            GL.AttachShader(_handle, vertexShader);
            GL.AttachShader(_handle, fragmentShader);

            GL.LinkProgram(_handle);

            GL.GetProgram(_handle, GetProgramParameterName.LinkStatus, out success);
            if (success == 0)
            {
                string infoLog = GL.GetProgramInfoLog(_handle);
                Console.WriteLine(infoLog);
            }

            GL.DetachShader(_handle, vertexShader);
            GL.DetachShader(_handle, fragmentShader);
            GL.DeleteShader(fragmentShader);
            GL.DeleteShader(vertexShader);
        }

        public void SetMatrix4(string name, Matrix4 matrix)
        {
            int location = GL.GetUniformLocation(_handle, name);
            if (location == -1)
            {
                Console.WriteLine($"Uniform '{name}' not found in shader.");
                return;
            }
            GL.UniformMatrix4(location, false, ref matrix);
        }

        public void SetVector3(string name, Vector3 vector3)
        {
            int location = GL.GetUniformLocation(_handle, name);
            if (location == -1)
            {
                Console.WriteLine($"Uniform '{name}' not found in shader.");
                return;
            }
            GL.Uniform3(location, ref vector3);
        }

        public void SetInt(string name, int value)
        {
            int location = GL.GetUniformLocation(_handle, name);
            if (location == -1)
            {
                Console.WriteLine($"Uniform '{name}' not found in shader.");
                return;
            }
            GL.Uniform1(location, value);
        }

        public void Use()
        {
            GL.UseProgram(_handle);
        }

        protected virtual void Dispose(bool disposing)
        {
            if (!disposedValue)
            {
                GL.DeleteProgram(_handle);

                disposedValue = true;
            }
        }

        ~Shader()
        {
            if (disposedValue == false)
            {
                Console.WriteLine("GPU Resource leak! Did you forget to call Dispose()?");
            }
        }

        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }
    }
}