use crate::{app::gl, models::{Mat4, Vec3}};

pub struct Shader {
  pub program: gl::types::GLuint,
  pub gl: std::rc::Rc<gl::Gl>,
}

impl Shader {
  pub fn use_program(&self) {
    unsafe { self.gl.UseProgram(self.program) };
  }

  pub fn set_uniform_mat4(&self, name: &str, mat: &Mat4) {
      unsafe {
          let loc = self.gl.GetUniformLocation(
              self.program,
              name.as_ptr() as *const i8
          );
          self.gl.UniformMatrix4fv(loc, 1, gl::FALSE, mat.as_ptr());
      }
  }

  pub fn set_uniform_vec3(&self, name: &str, v: &Vec3) {
      unsafe {
          let loc = self.gl.GetUniformLocation(self.program, name.as_ptr() as *const i8);
          self.gl.Uniform3f(loc, v.x, v.y, v.z);
      }
  }

  pub fn set_uniform_f32(&self, name: &str, v: f32) {
      unsafe {
          let loc = self.gl.GetUniformLocation(self.program, name.as_ptr() as *const i8);
          self.gl.Uniform1f(loc, v);
      }
  }

  pub fn set_uniform_i32(&self, name: &str, v: i32) {
      unsafe {
          let loc = self.gl.GetUniformLocation(self.program, name.as_ptr() as *const i8);
          self.gl.Uniform1i(loc, v);  // used for texture slots
      }
  }
}