#include "engine.h"
#include "ui_lua.h"
#include "gpu.h"
#include "draw.h"

void text_callback(GLFWwindow* window, unsigned int codepoint) {
  ClientContext* context = (ClientContext*)glfwGetWindowUserPointer(window);
  if(context->ui.active_container != NULL
  && ui_lua_dispatch_text(
    &context->ui,
    &context->render,
    context->ui.active_container,
    context->ui.active_layer,
    context->ui.active_element,
    codepoint)) return;

  if(context->app_text != NULL) context->app_text(context, codepoint);
}

void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods) {
  (void)scancode;
  (void)mods;

  ClientContext* context = (ClientContext*)glfwGetWindowUserPointer(window);

  if(context->ui.active_container != NULL
  && ui_lua_dispatch_key(
    &context->ui,
    &context->render,
    context->ui.active_container,
    context->ui.active_layer,
    context->ui.active_element,
    key, action, mods)) return;

  if(context->app_key != NULL) context->app_key(context, key, action, mods);
}

void button_callback(GLFWwindow* window, int button, int action, int mods) {
  double cursor[2];
  uint32_t container;
  uint32_t layer;
  uint32_t element;
  vec2 position;

  ClientContext* context = (ClientContext*)glfwGetWindowUserPointer(window);

  glfwGetCursorPos(window, &cursor[0], &cursor[1]);

  if(context->ui.active_container != NULL && context->ui.active_container->script_env != 0) {
    Container* container_ptr = context->ui.active_container;
    GPUDrawable* drawable_ptr = &container_ptr->layers[context->ui.active_layer].drawables_buffer[context->ui.active_element];
    vec2 element_pos = {
      drawable_ptr->pos[0] + container_ptr->data.offset[0],
      drawable_ptr->pos[1] + container_ptr->data.offset[1],
    };
    anchor_offset(&context->render, container_ptr, element_pos);
    vec2 element_size = {
      drawable_ptr->size[0],
      drawable_ptr->size[1],
    };

    vec2 point = {
      (cursor[0] - element_pos[0])/element_size[0],
      (cursor[1] - element_pos[1])/element_size[1],
    };

    if((point[0] <= 1 && point[0] >= 0 && point[1] <= 1 && point[1] >= 0) || action == GLFW_RELEASE) {
      ui_lua_dispatch_button(
          &context->ui,
          &context->render,
          container_ptr,
          context->ui.active_layer,
          context->ui.active_element,
          point[0],
          point[1],
          button,
          action,
          mods);
      return;
    } else {
      clear_active_element(&context->ui, &context->render);
    }
  }

  if(ui_intersect(cursor, &context->render, &context->ui, UI_EVENT_BUTTON, &container, &layer, &element, position)) {
    Container* container_ptr = context_container(container, &context->ui);
    if(ui_lua_dispatch_button(
        &context->ui,
        &context->render,
        container_ptr,
        layer,
        element,
        position[0],
        position[1],
        button,
        action,
        mods)) return;
  }

  if(context->app_button != NULL) context->app_button(context, cursor[0], cursor[1], button, action, mods);
}

void scroll_callback(GLFWwindow* window, double xoffset, double yoffset) {
  (void)xoffset;
  uint32_t container;
  uint32_t layer;
  uint32_t element;
  vec2 position;

  ClientContext* context = (ClientContext*)glfwGetWindowUserPointer(window);
  if(context->ui.active_container != NULL
  && ui_lua_dispatch_scroll(
    &context->ui,
    &context->render,
    context->ui.active_container,
    context->ui.active_layer,
    context->ui.active_element,
    xoffset, yoffset)) return;

  if(ui_intersect(
        context->ui.cursor,
        &context->render,
        &context->ui,
        UI_EVENT_SCROLL,
        &container,
        &layer,
        &element,
        position)) {
    Container* container_ptr = context_container(container, &context->ui);
    ui_lua_dispatch_scroll(
        &context->ui,
        &context->render,
        container_ptr,
        layer,
        element,
        xoffset,
        yoffset);
  }

  if(context->app_scroll != NULL) context->app_scroll(context, xoffset, yoffset);
}

void cursor_callback(GLFWwindow* window, double xpos, double ypos) {
  ClientContext* context = (ClientContext*)glfwGetWindowUserPointer(window);
  uint32_t container;
  uint32_t element;
  uint32_t layer;
  vec2 position;

  context->ui.cursor[0] = xpos;
  context->ui.cursor[1] = ypos;

  if(context->ui.active_container != NULL && context->ui.active_container->script_env != 0) {
    Container* container_ptr = context->ui.active_container;
    GPUDrawable* drawable_ptr = &container_ptr->layers[context->ui.active_layer].drawables_buffer[context->ui.active_element];
    vec2 element_pos = {
      drawable_ptr->pos[0] + container_ptr->data.offset[0],
      drawable_ptr->pos[1] + container_ptr->data.offset[1],
    };
    anchor_offset(&context->render, container_ptr, element_pos);
    vec2 element_size = {
      drawable_ptr->size[0],
      drawable_ptr->size[1],
    };
    if(ui_lua_dispatch_cursor(
        &context->ui,
        &context->render,
        container_ptr,
        context->ui.active_layer,
        context->ui.active_element,
        (context->ui.cursor[0] - element_pos[0])/element_size[0],
        (context->ui.cursor[1] - element_pos[1])/element_size[1])) return;
  }

  if(ui_intersect(context->ui.cursor, &context->render, &context->ui, UI_EVENT_CURSOR, &container, &layer, &element, position)) {
    Container* container_ptr = context_container(container, &context->ui);
    ui_lua_dispatch_cursor(
        &context->ui,
        &context->render,
        container_ptr,
        layer,
        element,
        position[0],
        position[1]);
  }

  if(context->app_cursor != NULL) context->app_cursor(context, xpos, ypos);
}

int app_main(ClientContext* context) {
  VkResult result;

  //
  double last_frame_time = 0;
  while(glfwWindowShouldClose(context->window) == 0) {
    double frame_time = glfwGetTime();
    double delta_time = (frame_time - last_frame_time);

    // Reset callback variables
    context->zoom = 0;

    glfwPollEvents();
    if(context->app_frame != NULL) context->app_frame(context);

    if((context->spin[0] != 0 || context->spin[1] != 0 ||
       context->velocity[0] != 0 || context->velocity[1] != 0 || context->velocity[2] != 0 ||
       context->zoom != 0 ||
       context->render.framebuffer_recreated == true)) {


      if(context->render.framebuffer_recreated == true) {
        context->render.framebuffer_recreated = false;
        VK_RESULT(update_hex_proj(&context->render, &context->hex));
        VK_RESULT(update_ui_context_resolution(&context->ui, &context->render));
      }

      context->rotation[0] += (float)context->spin[0]*delta_time*context->spin_speed; 
      if(context->rotation[0] > 2*M_PI) {
        context->rotation[0] -= 2*M_PI;
      } else if(context->rotation[0] < 0) {
        context->rotation[0] += 2*M_PI;
      }

      context->rotation[1] += (float)context->spin[1]*delta_time*context->spin_speed;
      if(context->rotation[1] > (M_PI/2 - 0.1)) {
        context->rotation[1] = (M_PI/2 - 0.1);
      } else if(context->rotation[1] < 0) {
        context->rotation[1] = 0;
      }

      context->position[0] += - context->velocity[2]*context->move_speed*cos(context->rotation[0])
                            - context->velocity[0]*context->move_speed*sin(context->rotation[0]);

      context->position[2] += context->velocity[0]*context->move_speed*cos(context->rotation[0])
                            - context->velocity[2]*context->move_speed*sin(context->rotation[0]);

      context->position[1] += context->velocity[1]*context->move_speed;

      context->distance += context->zoom*delta_time*context->zoom_speed;
      if(context->distance < 1) {
        context->distance = 1;
      }

      VK_RESULT(update_hex_view(
            context->position,
            context->rotation,
            context->distance,
            &context->render,
            &context->hex));
    }
    //

    VkResult result = draw_frame(&context->render, &context->ui, &context->hex, frame_time);
    if(result != VK_SUCCESS) {
      fprintf(stderr, "draw_frame error: %s\n", string_VkResult(result));
      glfwDestroyWindow(context->window);
    }

    last_frame_time = frame_time;
  }

  return 0;
}

int run_app(
    void* app_data,
    app_startup_function app_startup,
    app_frame_function app_frame,
    app_text_callback app_text,
    app_key_callback app_key,
    app_button_callback app_button,
    app_scroll_callback app_scroll,
    app_cursor_callback app_cursor) {
  ClientContext* context = malloc(sizeof(ClientContext));
  if(context == NULL) {
    return -1;
  }

  memset(context, 0, sizeof(ClientContext));
 
  context->window = init_window();

  context->rotation[0] = 3*M_PI/2;
  context->rotation[1] = M_PI/4;
  context->distance = 25;
  context->spin_speed = 1.0;
  context->zoom_speed = 1.0;
  context->move_speed = 0.1;
 
  memset(&context->render, 0, sizeof(RenderContext));
  memset(&context->ui, 0, sizeof(UIContext));
  memset(&context->hex, 0, sizeof(HexContext));

  context->app_data = app_data;
  context->app_frame = app_frame;
  context->app_text = app_text;
  context->app_key = app_key;
  context->app_button = app_button;
  context->app_scroll = app_scroll;
  context->app_cursor = app_cursor;

  glfwSetWindowUserPointer(context->window, context);
  glfwSetKeyCallback(context->window, key_callback);
  glfwSetMouseButtonCallback(context->window, button_callback);
  glfwSetScrollCallback(context->window, scroll_callback);
  glfwSetCursorPosCallback(context->window, cursor_callback);
  glfwSetCharCallback(context->window, text_callback);

  if(init_vulkan(context->window, &context->render) != VK_SUCCESS) return -2;
 
  // TODO: make # of fonts/textures/containers scaling, recreate GPU buffers as necessary
  if(create_ui_context(10, 10, 10, &context->render, &context->ui) != VK_SUCCESS) return -3;
  if(create_hex_context(&context->render, &context->hex) != VK_SUCCESS) return -4;

  if(app_startup != NULL) app_startup(context);

  return app_main(context);
}