#include "window.h"
#include "ui.h"
#include "draw.h"
#include <gtk/gtk.h>


static GtkWidget *drawingArea = NULL;
static GtkAdjustment *hAdjustment = NULL, *vAdjustment = NULL;


static gboolean deleteEvent(GtkWidget *widget, GdkEvent  *event, gpointer data) {
  return FALSE;
}

static gboolean scrollEvent(GtkWidget *widget, GdkEventScroll *event, gpointer user_data) {
  const gdouble x = event->x/widget->allocation.width, y = event->y/widget->allocation.height;
  
  switch(event->direction) {
    case GDK_SCROLL_UP:
      zoomIn(1.1, x, y);
      break;
    case GDK_SCROLL_DOWN:
      zoomOut(1.1, x, y);
  }
}

static void destroy(GtkWidget *widget, gpointer data) {
  gtk_main_quit();
}

static void refreshScrolling() {
  if(getImageWidth() < drawingArea->allocation.width)
    setXTranslate((getImageWidth()-drawingArea->allocation.width)/2);
  else
    setXTranslate(gtk_adjustment_get_value(hAdjustment));
  
  if(getImageHeight() < drawingArea->allocation.height)
    setYTranslate((getImageHeight()-drawingArea->allocation.height)/2);
  else 
    setYTranslate(gtk_adjustment_get_value(vAdjustment));
  
  gtk_widget_queue_draw(drawingArea);
}

static void updateScrollbars(double x, double y) {
  const gdouble imageWidth = getImageWidth(), imageHeight = getImageHeight();
  const gdouble width = drawingArea->allocation.width, height = drawingArea->allocation.height;
  gdouble upper, pageSize, value;
  
  gdk_window_freeze_updates(drawingArea->window);
  
  g_object_get(G_OBJECT(hAdjustment), "upper", &upper, "page_size", &pageSize, NULL);
  g_object_set(G_OBJECT(hAdjustment), "upper", imageWidth, "page_size", width, NULL);
  gtk_adjustment_changed(hAdjustment);
  
  if((pageSize > upper && width < imageWidth) || upper == 0)
    value = (imageWidth-width)/2;
  else
    value = (gtk_adjustment_get_value(hAdjustment)+pageSize*x)/upper*imageWidth-width*x;
  gtk_adjustment_set_value(hAdjustment, MAX(MIN(value, imageWidth-width), 0));
  
  g_object_get(G_OBJECT(vAdjustment), "upper", &upper, "page_size", &pageSize, NULL);
  g_object_set(G_OBJECT(vAdjustment), "upper", imageHeight, "page_size", height, NULL);
  
  if((pageSize > upper && height < imageHeight) || upper == 0)
    value = (imageHeight-height)/2;
  else
    value = (gtk_adjustment_get_value(vAdjustment)+pageSize*y)/upper*imageHeight-height*y;
  gtk_adjustment_set_value(vAdjustment, MAX(MIN(value, imageHeight-height), 0));
  
  gdk_window_thaw_updates(drawingArea->window);
  
  refreshScrolling();
}

static void updateScrollbarsCentered() {
  updateScrollbars(0.5, 0.5);
}

GtkWidget* createMainWindow() {
  GtkWidget *window, *vbox, *menubar, *toolbar, *table, *vScroll, *hScroll;
  GdkColor color = {0, 0, 0, 0};
  
  
  window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
  gtk_window_set_default_size(GTK_WINDOW(window), 640, 480);
  g_signal_connect(G_OBJECT(window), "delete-event", G_CALLBACK(deleteEvent), NULL);
  g_signal_connect(G_OBJECT(window), "destroy", G_CALLBACK(destroy), NULL);
  
  vbox = gtk_vbox_new(FALSE, 0);
  gtk_container_add(GTK_CONTAINER(window), vbox);
  
  menubar = getMenu();
  gtk_box_pack_start(GTK_BOX(vbox), menubar, FALSE, FALSE, 0);
  
  toolbar = getToolbar();
  gtk_box_pack_start(GTK_BOX(vbox), toolbar, FALSE, FALSE, 0);
  
  gtk_window_add_accel_group(GTK_WINDOW(window), getAccels());
  
  table = gtk_table_new(2, 2, FALSE);
  gtk_box_pack_end(GTK_BOX(vbox), table, TRUE, TRUE, 0);
  
  drawingArea = gtk_drawing_area_new();
  gtk_widget_modify_bg(drawingArea, GTK_WIDGET_STATE(drawingArea), &color);
  g_signal_connect(G_OBJECT(drawingArea), "configure-event", G_CALLBACK(updateScrollbarsCentered), NULL);
  g_signal_connect(G_OBJECT(drawingArea), "expose-event", G_CALLBACK(drawTopView), NULL);
  g_signal_connect(G_OBJECT(drawingArea), "scroll-event", G_CALLBACK(scrollEvent), NULL);
  gtk_widget_add_events(drawingArea, GDK_SCROLL_MASK);
  gtk_table_attach(GTK_TABLE(table), drawingArea, 0, 1, 0, 1, GTK_FILL|GTK_EXPAND|GTK_SHRINK, GTK_FILL|GTK_EXPAND|GTK_SHRINK, 0, 0);
  
  hAdjustment = GTK_ADJUSTMENT(gtk_adjustment_new(0, 0, 0, 10, 100, 100));
  hScroll = gtk_hscrollbar_new(hAdjustment);
  g_signal_connect(G_OBJECT(hScroll), "value-changed", G_CALLBACK(refreshScrolling), NULL);
  gtk_table_attach(GTK_TABLE(table), hScroll, 0, 1, 1, 2, GTK_FILL|GTK_EXPAND|GTK_SHRINK, 0, 0, 0);
  
  vAdjustment = GTK_ADJUSTMENT(gtk_adjustment_new(0, 0, 0, 10, 100, 100));
  vScroll = gtk_vscrollbar_new(vAdjustment);
  g_signal_connect(G_OBJECT(vScroll), "value-changed", G_CALLBACK(refreshScrolling), NULL);
  gtk_table_attach(GTK_TABLE(table), vScroll, 1, 2, 0, 1, 0, GTK_FILL|GTK_EXPAND|GTK_SHRINK, 0, 0);
  
  gtk_widget_show_all(vbox);
  
  return window;
}

void zoomIn(double factor, double x, double y) {
  setScale(getScale()*factor);
  updateScrollbars(x, y);
}

void zoomOut(double factor, double x, double y) {
  setScale(getScale()/factor);
  updateScrollbars(x, y);
}

void zoomInCentered(double factor) {
  zoomIn(factor, 0.5, 0.5);
}

void zoomOutCentered(double factor) {
  zoomOut(factor, 0.5, 0.5);
}