#include "engine.hpp"

#include <exception>
#include <game/components.hpp>
#include <glm/trigonometric.hpp>
#include <limits>
#include <ranges>

#include "glm/ext/matrix_clip_space.hpp"
#include "glm/ext/matrix_transform.hpp"
#include <glm/gtc/matrix_transform.hpp>

namespace {
[[nodiscard]] auto load_scene_to_renderer(trb::render::renderer &renderer,
                                          trb::game::scene &scene) {
  const auto upload_mesh_node = [&](const auto &mesh) {
    return renderer.register_mesh(
        mesh,
        scene.textures[scene.materials[mesh.material_index].albedo_texture]);
  };

  return scene.meshes | std::views::transform(upload_mesh_node) |
         std::ranges::to<std::vector<std::uint32_t>>();
}

[[nodiscard]] std::pair<glm::vec3, glm::vec3>
bounds_of(const trb::game::scene &scene) {
  auto min = glm::vec3(std::numeric_limits<float>::infinity());
  auto max = glm::vec3(-std::numeric_limits<float>::infinity());

  for (const auto &mesh : scene.meshes) {
    const auto transform = [mesh](glm::vec3 p) {
      return glm::vec3(mesh.transform * glm::vec4(p, 1.0f));
    };
    for (const auto [position, normal, uv] : mesh.vertices) {
      min = glm::min(min, transform(position));
      max = glm::max(max, transform(position));
    }
  }

  return std::make_pair(min, max);
}

struct level_view {
  glm::mat4 view;
  glm::mat4 projection;
};
[[nodiscard]] level_view calculate_camera_matrices(glm::vec3 min, glm::vec3 max,
                                                   float aspectRatio,
                                                   float zoom = 1.0f) {
  glm::vec3 center =
      glm::vec3((min.x + max.x) * 0.5f, 0.0f, (min.z + max.z) * 0.5f);

  float distance = 100.0f;
  glm::vec3 cameraPos = center + glm::vec3(0.0f, distance, distance);

  glm::mat4 view = glm::lookAt(cameraPos, center, glm::vec3(0.0f, 1.0f, 0.0f));

  glm::vec3 corners[8] = {{min.x, min.y, min.z}, {max.x, min.y, min.z},
                          {min.x, max.y, min.z}, {max.x, max.y, min.z},
                          {min.x, min.y, max.z}, {max.x, min.y, max.z},
                          {min.x, max.y, max.z}, {max.x, max.y, max.z}};

  float vMinX = FLT_MAX, vMaxX = -FLT_MAX;
  float vMinY = FLT_MAX, vMaxY = -FLT_MAX;

  for (const auto &corner : corners) {
    glm::vec4 vSpace = view * glm::vec4(corner, 1.0f);
    vMinX = glm::min(vMinX, vSpace.x);
    vMaxX = glm::max(vMaxX, vSpace.x);
    vMinY = glm::min(vMinY, vSpace.y);
    vMaxY = glm::max(vMaxY, vSpace.y);
  }

  float width = (vMaxX - vMinX) / zoom;
  float height = (vMaxY - vMinY) / zoom;
  float midX = (vMinX + vMaxX) * 0.5f;
  float midY = (vMinY + vMaxY) * 0.5f;

  if (aspectRatio > (width / height)) {
    width = height * aspectRatio;
  } else {
    height = width / aspectRatio;
  }

  glm::mat4 projection =
      glm::ortho(midX - width * 0.5f, midX + width * 0.5f, midY - height * 0.5f,
                 midY + height * 0.5f, -1000.0f, 1000.0f);

  return {view, projection};
}

} // namespace

namespace trb::game {

engine::game_models engine::load_models(std::filesystem::path model_path) {
  return {
      .boundary = load_glb(model_path / "level_scene.glb"),
      .boxes = load_glb(model_path / "boxes.glb"),
  };
}

std::vector<std::uint32_t> engine::load_scene_to_ecs(game::scene &scene) {

  const auto load_mesh =
      [this, &scene](const game::mesh_node &mesh) -> std::uint32_t {
    const auto entity = entities.create();

    const auto render_id = renderer.register_mesh(
        mesh,
        scene.textures[scene.materials[mesh.material_index].albedo_texture]);
    entities.emplace<components::render_id>(entity,
                                            components::render_id(render_id));

    return entity;
  };

  return scene.meshes | std::views::transform(load_mesh) |
         std::ranges::to<std::vector<std::uint32_t>>();
}

render::request
engine::add_level_bounds_to_render_request(render::request request) const {
  for (const auto eid : level_border_entity_ids) {
    const auto render_id = entities.get<components::render_id>(eid);
    request = request.add_mesh(static_cast<std::uint32_t>(render_id)).commit();
  }

  return request;
}

engine::engine()
    : display(&input, {1920, 1080}, "Tanks Reborn"), renderer(&display),
      models(load_models("../assets/models")),
      level_border_entity_ids(load_scene_to_ecs(models.boundary)) {}

void engine::run() {
  while (!display.should_close()) {
    display.poll_events();

    try {
      const auto [map_min, map_max] = ::bounds_of(models.boundary);
      const auto [view, projection] = ::calculate_camera_matrices(
          map_min, map_max, 1920.0f / 1080.0f, 3.0f);

      auto request = render::request();
      request = add_level_bounds_to_render_request(request);

      renderer.render(request, view, projection);
    } catch (const vuk::VkException &ex) {
      if (ex.what() != std::string("Out of date.")) {
        std::rethrow_exception(std::current_exception());
      }
    }
  }
}

} // namespace trb::game