#include <pgpl.h>
#include <stdlib.h>

static void get_slider_size(PGPL_GuiSliderWidget *slider_widget,
                            double *slider_x, double *slider_y, double x,
                            double y, double max_width, double max_height) {
  double offset;

  if (slider_widget->inversed) {
    offset = 1.0 - slider_widget->current_value;
  } else {
    offset = slider_widget->current_value;
  }

  if (slider_widget->vertical) {
    *slider_x = x - slider_widget->bar_height / 2.0;
    *slider_y = y + offset * (max_height - slider_widget->bar_height) -
                slider_widget->bar_height / 2.0;
  } else {
    *slider_x = x + offset * (max_width - slider_widget->bar_height) -
                slider_widget->bar_height / 2.0;
    *slider_y = y - slider_widget->bar_height / 2.0;
  }
}

static void get_content_size(PGPL_GuiWidget *widget, PGPL_GuiTheme *theme,
                             double *width, double *height, double max_width,
                             double max_height) {
  PGPL_GuiSliderWidget *slider_widget = (PGPL_GuiSliderWidget *)widget;

  (void)theme;

  if (slider_widget->vertical) {
    *width = slider_widget->bar_height;
    *height = max_height;
  } else {
    *width = max_width;
    *height = slider_widget->bar_height;
  }
}

static void render_content(PGPL_GuiWidget *widget, PGPL_Renderer *renderer,
                           PGPL_GuiTheme *theme, double x, double y,
                           double max_width, double max_height) {
  PGPL_GuiSliderWidget *slider_widget = (PGPL_GuiSliderWidget *)widget;

  double slider_x;
  double slider_y;

  double completion_x;
  double completion_y;
  double completion_width;
  double completion_height;

  get_slider_size(slider_widget, &slider_x, &slider_y, x, y, max_width,
                  max_height);

  if (slider_widget->vertical) {
    max_width = slider_widget->bar_height;
  } else {
    max_height = slider_widget->bar_height;
  }

  pgpl_render_rectangle(renderer, theme->text_color[widget->gui_color], x, y,
                        max_width, max_height);

  pgpl_render_rectangle(renderer, theme->background_color,
                        x + slider_widget->bar_height / 4.0,
                        y + slider_widget->bar_height / 4.0,
                        max_width - slider_widget->bar_height / 2.0,
                        max_height - slider_widget->bar_height / 2.0);

  max_width -= slider_widget->bar_height / 2.0;
  max_height -= slider_widget->bar_height / 2.0;

  if (slider_widget->inversed) {
    if (slider_widget->vertical) {
      completion_x = x + slider_widget->bar_height / 4.0;
      completion_y = y + slider_widget->bar_height / 4.0 +
                     max_height * (1.0 - slider_widget->current_value);
      completion_width = max_width;
      completion_height = max_height * slider_widget->current_value;
    } else {
      completion_x = x + slider_widget->bar_height / 4.0 +
                     max_width * (1.0 - slider_widget->current_value);
      completion_y = y + slider_widget->bar_height / 4.0;
      completion_width = max_width * slider_widget->current_value;
      completion_height = max_height;
    }
  } else {
    completion_x = x + slider_widget->bar_height / 4.0;
    completion_y = y + slider_widget->bar_height / 4.0;

    if (slider_widget->vertical) {
      completion_width = max_width;
      completion_height = max_height * slider_widget->current_value;
    } else {
      completion_width = max_width * slider_widget->current_value;
      completion_height = max_height;
    }
  }

  pgpl_render_rectangle(
      renderer, theme->widget_background_color[widget->gui_color], completion_x,
      completion_y, completion_width, completion_height);

  pgpl_render_circle(renderer, theme->text_color[widget->gui_color], slider_x,
                     slider_y, slider_widget->bar_height, 32);
}

static void event(PGPL_GuiWidget *widget, PGPL_GuiTheme *theme, PGPL_Gui *gui,
                  PGPL_WindowEventType event_type,
                  PGPL_WindowEventData *event_data, double x, double y,
                  double max_width, double max_height) {
  if (event_type == PGPL_WINDOW_EVENT_MOUSE_PRESS ||
      event_type == PGPL_WINDOW_EVENT_MOUSE_RELEASE ||
      event_type == PGPL_WINDOW_EVENT_MOUSE_MOVE) {
    PGPL_GuiSliderWidget *slider_widget = (PGPL_GuiSliderWidget *)widget;
    double slider_x;
    double slider_y;

    pgpl_gui_widget_adjust_event_params(widget, theme, &x, &y, &max_width,
                                        &max_height);

    get_slider_size(slider_widget, &slider_x, &slider_y, x, y, max_width,
                    max_height);

    if (event_type == PGPL_WINDOW_EVENT_MOUSE_PRESS) {
      if (pgpl_gui_widget_within_area(event_data->input_event.x,
                                      event_data->input_event.y, slider_x,
                                      slider_y, slider_widget->bar_height * 2,
                                      slider_widget->bar_height * 2)) {
        slider_widget->sliding = true;
        if (slider_widget->vertical) {
          slider_widget->last_pos = event_data->input_event.y;
        } else {
          slider_widget->last_pos = event_data->input_event.x;
        }
      }
    } else if (event_type == PGPL_WINDOW_EVENT_MOUSE_RELEASE) {
      slider_widget->sliding = false;
    } else if (slider_widget->sliding) {
      double new_pos;
      double axis_length;

      if (slider_widget->vertical) {
        new_pos = event_data->input_event.y;
        axis_length = max_height;
      } else {
        new_pos = event_data->input_event.x;
        axis_length = max_width;
      }

      axis_length -= slider_widget->bar_height;

      if (slider_widget->inversed) {
        slider_widget->current_value -=
            (new_pos - slider_widget->last_pos) / axis_length;
      } else {
        slider_widget->current_value +=
            (new_pos - slider_widget->last_pos) / axis_length;
      }

      if (slider_widget->current_value > 1.0) {
        slider_widget->current_value = 1.0;
      } else if (slider_widget->current_value < 0.0) {
        slider_widget->current_value = 0.0;
      }

      slider_widget->slide_callback(gui->app_data,
                                    slider_widget->current_value);

      slider_widget->last_pos = new_pos;
    }
  }
}

static void destroy(PGPL_GuiWidget *widget) {
  pgpl_gui_slider_widget_destroy((PGPL_GuiSliderWidget *)widget);
}

PGPL_GuiSliderWidget *pgpl_gui_slider_widget_create(
    uint32_t bar_height, bool inversed, bool vertical, double value,
    void (*slide_callback)(void *app_data, double value)) {
  PGPL_GuiSliderWidget *slider_widget = calloc(1, sizeof(*slider_widget));
  slider_widget->parent.id = "PGPL_GuiSliderWidget";
  slider_widget->parent.get_content_size = get_content_size;
  slider_widget->parent.render_content = render_content;
  slider_widget->parent.event = event;
  slider_widget->parent.destroy = destroy;
  slider_widget->bar_height = bar_height;
  slider_widget->inversed = inversed;
  slider_widget->vertical = vertical;
  slider_widget->current_value = value;
  slider_widget->slide_callback = slide_callback;
  return slider_widget;
}

void pgpl_gui_slider_widget_destroy(PGPL_GuiSliderWidget *slider_widget) {
  free(slider_widget);
}