#include "shaders.h"
#include "aliases.h"
#include "depth_shader.h"
#include "main_shader.h"
#include "render.h"
#include "shader.h"
#include "vec.h"

ShaderID perspective_diffuse  = {0};
ShaderID perspective_albedo   = {0};
ShaderID orthographic_diffuse = {0};
ShaderID orthographic_albedo  = {0};
ShaderID depth                = {0};

internal Shader perspective       = {0};
internal Shader orthographic      = {0};
internal DepthShader depth_shader = {0};

internal V3f g_ambient_light = {0.1f, 0.1f, 0.1f};
internal V3f g_eye           = {0.2f, -0.1f, 0.5f};
internal V3f g_target        = {0};
internal V3f g_up            = {0.0f, 1.0f, 0.0f};
internal V3f g_light_dir     = {1.0f, -1.0f, 1.0f};

internal M4x4f get_projection_matrix(ProjectionType projection_type);

void load_shaders(M4x4f vp) {
  M4x4f model_view              = lookat(g_eye, g_target, g_up);
  M4x4f orthographic_projection = get_projection_matrix(PROJECTION_TYPE_ORTHOGRAPHIC);
  M4x4f perspective_projection  = get_projection_matrix(PROJECTION_TYPE_PERSPECTIVE);

  // Set up perspective shader
  perspective.proj_mv       = mat4x4_mul(perspective_projection, model_view);
  perspective.proj_mv_inv_t = mat4x4_inv(mat4x4_transpose(perspective.proj_mv));
  perspective.viewport      = vp;
  perspective.final         = mat4x4_mul(perspective.viewport, perspective.proj_mv);
  perspective.light_dir     = mat3x3_mul_vec3(perspective.proj_mv, g_light_dir);
  normalise_v3(perspective.light_dir);
  perspective.ambient       = g_ambient_light;

  // Set up orthographic shader
  orthographic.proj_mv       = mat4x4_mul(orthographic_projection, model_view);
  orthographic.proj_mv_inv_t = mat4x4_inv(mat4x4_transpose(orthographic.proj_mv));
  orthographic.viewport      = vp;
  orthographic.final         = mat4x4_mul(orthographic.viewport, orthographic.proj_mv);
  orthographic.light_dir     = mat3x3_mul_vec3(orthographic.proj_mv, g_light_dir);
  normalise_v3(orthographic.light_dir);
  orthographic.ambient       = g_ambient_light;

  // Set up depth shader
  M4x4f depth_model_view = lookat(g_light_dir, g_target, g_up);
  M4x4f depth_projection = projection(0.0f);

  depth_shader.proj_mv       = mat4x4_mul(depth_projection, depth_model_view);
  depth_shader.proj_mv_inv_t = mat4x4_inv(mat4x4_transpose(depth_shader.proj_mv));
  depth_shader.viewport      = vp;
  depth_shader.final         = mat4x4_mul(depth_shader.viewport, depth_shader.proj_mv);
  depth_shader.light_dir     = mat3x3_mul_vec3(depth_shader.proj_mv, g_light_dir);
  normalise_v3(depth_shader.light_dir);

  // Register shaders
  perspective_diffuse  = register_shader(&perspective, general_shader_vertex, diffuse_shader_fragment);
  perspective_albedo   = register_shader(&perspective, general_shader_vertex, albedo_shader_fragment);
  orthographic_diffuse = register_shader(&orthographic, general_shader_vertex, diffuse_shader_fragment);
  orthographic_albedo  = register_shader(&orthographic, general_shader_vertex, albedo_shader_fragment);
  depth                = register_shader(&depth_shader, depth_shader_vertex, depth_shader_fragment);
}

internal M4x4f get_projection_matrix(ProjectionType projection_type) {
  if (projection_type == PROJECTION_TYPE_PERSPECTIVE) {
    V3f cam = V3(V3f, f32, g_target.x, g_target.y, g_target.z, g_eye.x, g_eye.y, g_eye.z);
    normalise_v3(cam);

    f32 coeff = -1.0f / magnitude_v3(cam) * 0.5f;

    return projection(coeff);
  }

  return mat4x4_identity;
}