#include <gtk/gtk.h>
#include <cairo/cairo.h>
#include <portaudio.h>

int device = -1;

typedef struct {
	float left;
	float right;
} AudioData;

AudioData audiodata;

struct data {
	int device_num;
};

PaStream *stream = NULL;
GtkWidget *drawing_area;

#define FRAMES_PER_BUFFER 256

int patestCallback(const void *inputBuffer, void *outputBuffer, unsigned long framesPerBuffer, const PaStreamCallbackTimeInfo *timeInfo, PaStreamCallbackFlags statusFlags, void *userData)
{
	AudioData *data = (AudioData *)userData;
	float *in = (float *)inputBuffer;

	if (data->left > 0) {
		data->left -= 0.005;
	}

	if (data->right > 0) {
		data->right -= 0.005;
	}

	for (unsigned long i = 0; i < framesPerBuffer * 2; i += 2) {
		data->left = MAX(data->left, fabs(in[i]));
		data->right = MAX(data->right, fabs(in[i + 1]));
	}

	if (drawing_area) {
		gtk_widget_queue_draw(GTK_WIDGET(drawing_area));
	}

	return 0;
}

static void select_device(GtkWidget *widget, gpointer data)
{
	if (stream != NULL) {
		Pa_StopStream(stream);
		Pa_CloseStream(stream);
		stream = NULL;
	}

	struct data *d = (struct data *)data;
	device = d->device_num;
	printf("Device %d  selected\n", d->device_num);

	PaStreamParameters inputParameters;
	memset(&inputParameters, 0, sizeof(inputParameters));
	inputParameters.channelCount = 2;
	inputParameters.device = device;
	inputParameters.hostApiSpecificStreamInfo = NULL;
	inputParameters.sampleFormat = paFloat32;
	inputParameters.suggestedLatency = Pa_GetDeviceInfo(device)->defaultLowInputLatency;

	Pa_OpenStream(&stream, &inputParameters, NULL, Pa_GetDeviceInfo(device)->defaultSampleRate, FRAMES_PER_BUFFER, paNoFlag, patestCallback, &audiodata);
	Pa_StartStream(stream);
}

static void draw(cairo_t *cr, GtkWidget *area)
{
	cairo_set_source_rgba(cr, 1, 0, 0, 1);
	cairo_arc(cr, 250, 250, audiodata.left * 250, 0, 2 * M_PI);
	cairo_arc(cr, 800, 250, audiodata.right * 250, 0, 2 * M_PI);
	cairo_fill(cr);

	gtk_widget_queue_draw(area);
}

static void draw_cb(GtkDrawingArea *drawing_area, cairo_t *cr, int width, int height, gpointer data)
{
	cairo_paint(cr);
	draw(cr, data);
}

static void refresh()
{
}

static void activate(GtkApplication *app, gpointer user_data)
{
	GtkWidget *window;
	GtkWidget *grid;
	GtkWidget *button;

	// init window
	window = gtk_application_window_new(app);
	gtk_window_set_title(GTK_WINDOW(window), "Directional Audio Visualizer");

	// init grid
	grid = gtk_grid_new();
	gtk_window_set_child(GTK_WINDOW(window), grid);

	// init drawing_area
	drawing_area = gtk_drawing_area_new();
	gtk_widget_set_size_request(drawing_area, 1050, 500);
	gtk_drawing_area_set_draw_func(GTK_DRAWING_AREA(drawing_area), draw_cb, drawing_area, NULL);
	gtk_grid_attach(GTK_GRID(grid), drawing_area, 1, 2, 100, 100);

	// init audio devices
	Pa_Initialize();
	int numDevices = Pa_GetDeviceCount();

	if (numDevices < 0) {
		printf("Error getting device count.\n");
		exit(EXIT_FAILURE);
	} else if (numDevices == 0) {
		printf("There are no available audio devices on this machine.\n");
		exit(EXIT_SUCCESS);
	}

	// init button for every audio device
	for (int i = 0; i < numDevices; i++) {
		const PaDeviceInfo *deviceInfo = Pa_GetDeviceInfo(i);
		struct data *d = malloc(sizeof(struct data));
		d->device_num = i;
		button = gtk_button_new_with_label(deviceInfo->name);
		g_signal_connect(button, "clicked", G_CALLBACK(select_device), d);
		gtk_grid_attach(GTK_GRID(grid), button, 0, numDevices - i - 1, 1, 1);
	}

	// init button for refresh
	button = gtk_button_new_with_label("Refresh");
	g_signal_connect_swapped(button, "clicked", G_CALLBACK(refresh), window);
	gtk_grid_attach(GTK_GRID(grid), button, 1, 0, 1, 1);

	// init button for quit
	button = gtk_button_new_with_label("Quit");
	g_signal_connect_swapped(button, "clicked", G_CALLBACK(gtk_window_destroy), window);
	gtk_grid_attach(GTK_GRID(grid), button, 1, 1, 1, 1);

	// set window
	gtk_window_present(GTK_WINDOW(window));
}

int main(int argc, char **argv)
{
	GtkApplication *app;
	int status;

	app = gtk_application_new("org.gtk.example", G_APPLICATION_DEFAULT_FLAGS);
	g_signal_connect(app, "activate", G_CALLBACK(activate), NULL);
	status = g_application_run(G_APPLICATION(app), argc, argv);
	g_object_unref(app);

	return status;
}