#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <gnome.h>
#include "echo.h"

#define MAX_SRATE 50000
#define MAX_CHANNELS 2
#define BYTES_PS 2
#define BUFFER_SAMPLES (MAX_SRATE * MAX_DELAY / 1000)
#define BUFFER_SHORTS (BUFFER_SAMPLES * MAX_CHANNELS)
#define BUFFER_BYTES (BUFFER_SHORTS * BYTES_PS)

static gint16 *buffer = NULL;
gboolean echo_surround_enable = TRUE;
static int w_ofs;

void echo_init(struct _echo *echo)
{
	memset(echo,0,sizeof(struct _echo));
	
    gnome_config_push_prefix("/liteamp/echo/");
	
	/* read from config file ... if fail, set default */
	echo->on = gnome_config_get_bool("on=FALSE");
	echo->delay = gnome_config_get_int("delay=200");
	echo->feedback = gnome_config_get_int("feedback=30");
	echo->wet = gnome_config_get_int("wet=25");

	gnome_config_pop_prefix();
}

void echo_quit(void)
{
	g_free(buffer);
	buffer = NULL;	
}

void echo_apply_change(struct _echo *echo)
{
	/* get value from widget and write config file */
	echo->on = gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(echo->chk));
	echo->delay = (gint)gtk_range_get_value(GTK_RANGE(echo->hs_echo_delay));
	echo->feedback = (gint)gtk_range_get_value(GTK_RANGE(echo->hs_echo_feedback));
	echo->wet = (gint)gtk_range_get_value(GTK_RANGE(echo->hs_echo_wet));
    
	gnome_config_push_prefix("/liteamp/echo/");

	gnome_config_set_bool("on",echo->on);
	gnome_config_set_int("delay",echo->delay);
	gnome_config_set_int("feedback",echo->feedback);
	gnome_config_set_int("wet",echo->wet);
	
	gnome_config_pop_prefix();
}

gint echo_play_it(gint16** d, gint length,struct _echo *echo,gint nch,gint srate,gint bitrate)
{
	gint echo_delay = echo->delay;
	gint echo_feedback = echo->feedback;
	gint echo_volume = echo->wet;
	gint i, in, out, buf, r_ofs, fb_div;
	gint16 *data = (gint16 *) * d;
	static gint old_srate, old_nch;

	if (!buffer)
		buffer = g_malloc0(BUFFER_BYTES + 2);

	if (nch != old_nch || srate != old_srate)
	{
		memset(buffer, 0, BUFFER_BYTES);
		w_ofs = 0;
		old_nch = nch;
		old_srate = srate;
	}

	if (echo_surround_enable && nch == 2)
		fb_div = 200;
	else
		fb_div = 100;

	r_ofs = w_ofs - (srate * echo_delay / 1000) * nch;
	if (r_ofs < 0)
		r_ofs += BUFFER_SHORTS;

	for (i = 0; i < length / BYTES_PS; i++)
	{
		in = data[i];
		buf = buffer[r_ofs];
		if (echo_surround_enable && nch == 2)
		{
			if (i & 1)
				buf -= buffer[r_ofs - 1];
			else
				buf -= buffer[r_ofs + 1];
		}
		out = in + buf * echo_volume / 100;
		buf = in + buf * echo_feedback / fb_div;
		out = CLAMP(out, -32768, 32767);
		buf = CLAMP(buf, -32768, 32767);
		buffer[w_ofs] = buf;
		data[i] = out;
		if (++r_ofs >= BUFFER_SHORTS)
			r_ofs -= BUFFER_SHORTS;
		if (++w_ofs >= BUFFER_SHORTS)
			w_ofs -= BUFFER_SHORTS;
	}

	return length;
}