#include <math.h>
#include <time.h>
#include <gtk/gtk.h>
#include <al.h>
#include <alc.h>


const double pi = 3.141592653589793;

GtkWidget *hours[3], *minutes[3];
GtkWidget *enable_alarm;


// This function plays beep via OpenAL.
// It's may be difficult to understand how it works, so just use it as is.
// This function uses OpenAL, so you need
//   to include <al.h> and <alc.h>
//   and link with OpenAL library (for GCC add param: -lopenal)
void beep() {
  const int frequency = 440;
  const int rate = 10000;

  ALCshort samples[2000];
  const int count = 2000;
  
  for(int i = 0; i < count; ++i)
    samples[i] = (int)(32760*sin(2*pi*i*frequency/rate));

  ALCdevice *device = alcOpenDevice(NULL);
  ALCcontext *context = alcCreateContext(device, NULL);
  alcMakeContextCurrent(context);

  ALuint buffer, source;
  alGenBuffers(1, &buffer);
  alBufferData(buffer, AL_FORMAT_MONO16, samples, sizeof(samples), rate);
  alGenSources(1, &source);
  alSourcei(source, AL_BUFFER, buffer);
  alSourcePlay(source);
  
  g_usleep(count*1000000/rate + 10000);

  alcMakeContextCurrent(NULL);
  alcDestroyContext(context);
  alcCloseDevice(device);
}

gboolean timeout(gpointer data) {
  if (gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(enable_alarm))) {
    time_t timer = time(NULL);
    struct tm *t = localtime(&timer);
    for(int i = 0; i < 3; ++i) {
      int hour = gtk_spin_button_get_value_as_int(GTK_SPIN_BUTTON(hours[i]));
      int minute = gtk_spin_button_get_value_as_int(GTK_SPIN_BUTTON(minutes[i]));
      if (hour == t->tm_hour && minute == t->tm_min)
        beep();
    }
  }  
  return TRUE;
}

void activate(GtkApplication* app, gpointer data) {
  GtkWidget *window = gtk_application_window_new (app);
  gtk_container_set_border_width(GTK_CONTAINER(window), 10);  
  
  GtkWidget *vbox = gtk_box_new(GTK_ORIENTATION_VERTICAL, 5);
  gtk_container_add(GTK_CONTAINER(window), vbox);
  
  GtkWidget *label = gtk_label_new("Set following three alarm clocks,\nenable alarm\nand take a sleep.");
  gtk_container_add(GTK_CONTAINER(vbox), label);
  
  for(int i = 0; i < 3; ++i) {
    GtkWidget *hbox = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, 5);
    gtk_container_add(GTK_CONTAINER(vbox), hbox);
    
    hours[i] = gtk_spin_button_new(NULL, 1.2, 0);
    gtk_spin_button_set_range(GTK_SPIN_BUTTON(hours[i]), 0.0, 23.0);
    gtk_spin_button_set_increments(GTK_SPIN_BUTTON(hours[i]), 1.0, 10.0);
    gtk_spin_button_set_wrap(GTK_SPIN_BUTTON(hours[i]), TRUE);
    gtk_container_add(GTK_CONTAINER(hbox), hours[i]);

    minutes[i] = gtk_spin_button_new(NULL, 1.2, 0);
    gtk_spin_button_set_range(GTK_SPIN_BUTTON(minutes[i]), 0.0, 59.0);
    gtk_spin_button_set_increments(GTK_SPIN_BUTTON(minutes[i]), 1.0, 10.0);
    gtk_spin_button_set_wrap(GTK_SPIN_BUTTON(minutes[i]), TRUE);
    gtk_container_add(GTK_CONTAINER(hbox), minutes[i]);
  }
  
  // set initial values
  time_t timer = time(NULL);
  struct tm *t = localtime(&timer);
  int h = t->tm_hour;
  int m = t->tm_min;
  
  gtk_spin_button_set_value(GTK_SPIN_BUTTON(hours[0]), h);
  gtk_spin_button_set_value(GTK_SPIN_BUTTON(minutes[0]), m);
  
  m += 1;
  if (m >= 60) { m -= 60; h = (h + 1)%24; }
  gtk_spin_button_set_value(GTK_SPIN_BUTTON(hours[1]), h);
  gtk_spin_button_set_value(GTK_SPIN_BUTTON(minutes[1]), m);
  
  m += 4;
  if (m >= 60) { m -= 60; h = (h + 1)%24; }
  gtk_spin_button_set_value(GTK_SPIN_BUTTON(hours[2]), h);
  gtk_spin_button_set_value(GTK_SPIN_BUTTON(minutes[2]), m);

  enable_alarm = gtk_check_button_new_with_label("Enable alarm");
  gtk_container_add(GTK_CONTAINER(vbox), enable_alarm);
  
  gtk_widget_show_all(window);
  
  g_timeout_add(1000, timeout, NULL);
}

int main(int argc, char **argv) {
  GtkApplication *application = gtk_application_new(NULL, 0);
  g_signal_connect(application, "activate", G_CALLBACK(activate), NULL);
  int status = g_application_run(G_APPLICATION(application), argc, argv);
  g_object_unref(application);
  return status;
}