#include <stdlib.h>
#include "ibm.h"
#include "filters.h"
#include "lpt.h"
#include "lpt_dac.h"
#include "sound.h"

typedef struct lpt_dac_t {
	uint8_t dac_val_l, dac_val_r;

	int is_stereo;
	int channel;

	int16_t buffer[2][MAXSOUNDBUFLEN];
	int pos;
} lpt_dac_t;

static void dac_update(lpt_dac_t *lpt_dac) {
	for (; lpt_dac->pos < sound_pos_global; lpt_dac->pos++) {
		lpt_dac->buffer[0][lpt_dac->pos] = (int8_t)(lpt_dac->dac_val_l ^ 0x80) * 0x40;
		lpt_dac->buffer[1][lpt_dac->pos] = (int8_t)(lpt_dac->dac_val_r ^ 0x80) * 0x40;
	}
}

static void dac_write_data(uint8_t val, void *p) {
	lpt_dac_t *lpt_dac = (lpt_dac_t *)p;

	if (lpt_dac->is_stereo) {
		if (lpt_dac->channel)
			lpt_dac->dac_val_r = val;
		else
			lpt_dac->dac_val_l = val;
	} else
		lpt_dac->dac_val_l = lpt_dac->dac_val_r = val;
	dac_update(lpt_dac);
}

static void dac_write_ctrl(uint8_t val, void *p) {
	lpt_dac_t *lpt_dac = (lpt_dac_t *)p;

	if (lpt_dac->is_stereo)
		lpt_dac->channel = val & 0x01;
}

static uint8_t dac_read_status(void *p) {
	return 0;
}

static void dac_get_buffer(int32_t *buffer, int len, void *p) {
	lpt_dac_t *lpt_dac = (lpt_dac_t *)p;
	int c;

	dac_update(lpt_dac);

	for (c = 0; c < len; c++) {
		buffer[c * 2] += dac_iir(0, lpt_dac->buffer[0][c]);
		buffer[c * 2 + 1] += dac_iir(1, lpt_dac->buffer[1][c]);
	}
	lpt_dac->pos = 0;
}

static void *dac_init() {
	lpt_dac_t *lpt_dac = malloc(sizeof(lpt_dac_t));
	memset(lpt_dac, 0, sizeof(lpt_dac_t));

	sound_add_handler(dac_get_buffer, lpt_dac);

	return lpt_dac;
}
static void *dac_stereo_init() {
	lpt_dac_t *lpt_dac = dac_init();

	lpt_dac->is_stereo = 1;

	return lpt_dac;
}
static void dac_close(void *p) {
	lpt_dac_t *lpt_dac = (lpt_dac_t *)p;

	free(lpt_dac);
}

lpt_device_t lpt_dac_device =
	{
		"LPT DAC / Covox Speech Thing",
		0,
		dac_init,
		dac_close,
		NULL,
		NULL,
		NULL,
		NULL,
		NULL,
		dac_write_data,
		dac_write_ctrl,
		dac_read_status,
	};
lpt_device_t lpt_dac_stereo_device =
	{
		"Stereo LPT DAC",
		0,
		dac_stereo_init,
		dac_close,
		NULL,
		NULL,
		NULL,
		NULL,
		NULL,
		dac_write_data,
		dac_write_ctrl,
		dac_read_status,
	};
