#include <isogfx/isogfx.h>

#include <gfx/gfx.h>
#include <gfx/gfx_app.h>
#include <gfx/render_backend.h>
#include <gfx/renderer.h>
#include <gfx/scene.h>
#include <gfx/util/geometry.h>
#include <gfx/util/shader.h>

#include <assert.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>

static const int SCREEN_WIDTH  = 1408;
static const int SCREEN_HEIGHT = 960;
static const int TILE_WIDTH    = 64;
static const int TILE_HEIGHT   = TILE_WIDTH / 2;
static const int WORLD_WIDTH   = 20;
static const int WORLD_HEIGHT  = 20;

static const Pixel BLACK = (Pixel){.r = 0x38, .g = 0x3b, .b = 0x46};
static const Pixel WHITE = (Pixel){.r = 0xA5, .g = 0xb3, .b = 0xc0};
static const Pixel RED   = (Pixel){.r = 0xdc, .g = 0x76, .b = 0x84};

typedef struct State {
  Gfx*     gfx;
  IsoGfx*  iso;
  Tile     red;
  int      xpick;
  int      ypick;
  Texture* screen_texture;
  Scene*   scene;
} State;

static void make_checkerboard(IsoGfx* iso, Tile black, Tile white) {
  assert(iso);
  for (int y = 0; y < isogfx_world_height(iso); ++y) {
    for (int x = 0; x < isogfx_world_width(iso); ++x) {
      const int  odd_col = x & 1;
      const int  odd_row = y & 1;
      const Tile value   = (odd_row ^ odd_col) == 0 ? black : white;
      isogfx_set_tile(iso, x, y, value);
    }
  }
}

static bool init(const GfxAppDesc* desc, void** app_state) {
  State* state = calloc(1, sizeof(State));
  if (!state) {
    return false;
  }

  if (!(state->iso = isogfx_new(&(IsoGfxDesc){
            .screen_width  = SCREEN_WIDTH,
            .screen_height = SCREEN_HEIGHT,
            .tile_width    = TILE_WIDTH,
            .tile_height   = TILE_HEIGHT,
            .world_width   = WORLD_WIDTH,
            .world_height  = WORLD_HEIGHT}))) {
    goto cleanup;
  }
  if (!(state->gfx = gfx_init())) {
    goto cleanup;
  }
  RenderBackend* render_backend = gfx_get_render_backend(state->gfx);

  if (!(state->screen_texture = gfx_make_texture(
            render_backend, &(TextureDesc){
                                .width     = SCREEN_WIDTH,
                                .height    = SCREEN_HEIGHT,
                                .dimension = Texture2D,
                                .format    = TextureRGB8,
                                .filtering = NearestFiltering,
                                .wrap      = ClampToEdge,
                                .mipmaps   = false}))) {
    goto cleanup;
  }

  ShaderProgram* shader = gfx_make_view_texture_shader(render_backend);
  if (!shader) {
    goto cleanup;
  }

  Geometry* geometry = gfx_make_quad_11(render_backend);
  if (!geometry) {
    goto cleanup;
  }

  MaterialDesc material_desc = (MaterialDesc){.num_uniforms = 1};
  material_desc.uniforms[0]  = (ShaderUniform){
       .type          = UniformTexture,
       .value.texture = state->screen_texture,
       .name          = sstring_make("Texture")};
  Material* material = gfx_make_material(&material_desc);
  if (!material) {
    return false;
  }

  const MeshDesc mesh_desc =
      (MeshDesc){.geometry = geometry, .material = material, .shader = shader};
  Mesh* mesh = gfx_make_mesh(&mesh_desc);
  if (!mesh) {
    goto cleanup;
  }

  SceneObject* object = gfx_make_object();
  if (!object) {
    goto cleanup;
  }
  gfx_add_object_mesh(object, mesh);

  state->scene    = gfx_make_scene();
  SceneNode* node = gfx_make_object_node(object);
  SceneNode* root = gfx_get_scene_root(state->scene);
  gfx_set_node_parent(node, root);

  const Tile black = isogfx_make_tile(
      state->iso, &(TileDesc){.type = TileFromColour, .colour = BLACK});
  const Tile white = isogfx_make_tile(
      state->iso, &(TileDesc){.type = TileFromColour, .colour = WHITE});
  state->red = isogfx_make_tile(
      state->iso, &(TileDesc){.type = TileFromColour, .colour = RED});
  make_checkerboard(state->iso, black, white);
  isogfx_render(state->iso);

  *app_state = state;
  return true;

cleanup:
  if (state->gfx) {
    gfx_destroy(&state->gfx);
  }
  free(state);
  return false;
}

static void shutdown(void* app_state) {
  assert(app_state);
  State* state = (State*)(app_state);
  isogfx_del(&state->iso);
  gfx_destroy(&state->gfx);
  free(app_state);
}

static void update(void* app_state, double t, double dt) {
  assert(app_state);
  State* state = (State*)(app_state);

  double mouse_x, mouse_y;
  gfx_app_get_mouse_position(&mouse_x, &mouse_y);

  isogfx_pick_tile(state->iso, mouse_x, mouse_y, &state->xpick, &state->ypick);

  printf("Picked tile: (%d, %d)\n", state->xpick, state->ypick);
}

static void render(void* app_state) {
  assert(app_state);
  State* state = (State*)(app_state);

  isogfx_render(state->iso);
  if ((state->xpick != -1) && (state->ypick != -1)) {
    isogfx_draw_tile(state->iso, state->xpick, state->ypick, state->red);
  }

  const Pixel* screen = isogfx_get_screen_buffer(state->iso);
  assert(screen);
  gfx_update_texture(
      state->screen_texture, &(TextureDataDesc){.pixels = screen});

  RenderBackend* render_backend = gfx_get_render_backend(state->gfx);
  Renderer*      renderer       = gfx_get_renderer(state->gfx);

  gfx_start_frame(render_backend);
  gfx_render_scene(
      renderer, &(RenderSceneParams){
                    .mode = RenderDefault, .scene = state->scene, .camera = 0});
  gfx_end_frame(render_backend);
}

static void resize(void* app_state, int width, int height) {
  assert(app_state);
  State* state = (State*)(app_state);

  RenderBackend* render_backend = gfx_get_render_backend(state->gfx);
  gfx_set_viewport(render_backend, width, height);
}

int main(int argc, const char** argv) {
  const int initial_width  = SCREEN_WIDTH;
  const int initial_height = SCREEN_HEIGHT;
  const int max_fps        = 60;

  gfx_app_run(
      &(GfxAppDesc){
          .argc              = argc,
          .argv              = argv,
          .width             = initial_width,
          .height            = initial_height,
          .max_fps           = max_fps,
          .update_delta_time = max_fps > 0 ? 1.0 / (double)max_fps : 0.0,
          .title             = "Isometric Renderer"},
      &(GfxAppCallbacks){
          .init     = init,
          .update   = update,
          .render   = render,
          .resize   = resize,
          .shutdown = shutdown});

  return 0;
}