/* SPDX-License-Identifier: GPL-2.0 */

/** \file wav_filter.c A filter that inserts a wave header. */

#include "para.h"
#include "error.h"
#include "list.h"
#include "sched.h"
#include "buffer_tree.h"
#include "filter.h"
#include "string.h"
#include "portable_io.h"

/** A wav header is always 44 bytes. */
#define WAV_HEADER_LEN 44
/** Always write 16 bit header. */
#define BITS 16

static void make_wav_header(unsigned int channels, unsigned int sample_rate,
		char *headbuf)
{

	unsigned int size = 0x7fffffff;
	int bytespersec = channels * sample_rate * BITS / 8;
	int align = channels * BITS / 8;

	PARA_DEBUG_LOG("writing wave header: %u channels, %u KHz\n", channels, sample_rate);
	memset(headbuf, 0, WAV_HEADER_LEN);
	memcpy(headbuf, "RIFF", 4);
	write_u32(headbuf + 4, size - 8);
	memcpy(headbuf + 8, "WAVE", 4);
	memcpy(headbuf + 12, "fmt ", 4);
	write_u32(headbuf + 16, 16); /* 16 + extra format bytes (zero) */
	write_u16(headbuf + 20, 1);	/* format (1 == PCM/uncompressed) */
	write_u16(headbuf + 22, channels);
	write_u32(headbuf + 24, sample_rate);
	write_u32(headbuf + 28, bytespersec);
	write_u16(headbuf + 32, align); /* number of bytes per sample slice */
	write_u16(headbuf + 34, BITS); /* significant bits per sample */
	memcpy(headbuf + 36, "data", 4); /* chunk ID */
	write_u32(headbuf + 40, size - 44); /* chunk size */
}

static void wav_close(struct filter_node *fn)
{
	free(fn->private_data);
	fn->private_data = NULL;
}

static void wav_open(struct filter_node *fn)
{
	int *bof;

	fn->private_data = alloc(sizeof(int));
	bof = fn->private_data;
	*bof = 1;
}

static void wav_pre_monitor(struct sched *s, void *context)
{
	struct filter_node *fn = context;
	size_t iqs = btr_get_input_queue_size(fn->btrn);

	if (iqs == 0)
		return;
	sched_min_delay(s);
}

static int wav_post_monitor(__a_unused struct sched *s, void *context)
{
	struct filter_node *fn = context;
	struct btr_node *btrn = fn->btrn;
	size_t iqs = btr_get_input_queue_size(btrn);
	int ret;
	char *header, *buf;
	int32_t rate, ch;

	if (iqs == 0) {
		ret = -E_EOF;
		if (btr_no_parent(btrn))
			goto err;
		return 0;
	}
	ret = btr_exec_up(btrn, "sample_rate", &buf);
	if (ret < 0) {
		ret = -E_WAV_BAD_FC;
		goto err;
	}
	ret = para_atoi32(buf, &rate);
	free(buf);
	if (ret < 0)
		goto err;
	ret = btr_exec_up(btrn, "channels", &buf);
	if (ret < 0) {
		ret = -E_WAV_BAD_FC;
		goto err;
	}
	ret = para_atoi32(buf, &ch);
	free(buf);
	if (ret < 0)
		goto err;
	header = alloc(WAV_HEADER_LEN);
	make_wav_header(ch, rate, header);
	btr_add_output(header, WAV_HEADER_LEN, btrn);
	ret = -E_WAV_SUCCESS;
err:
	if (ret == -E_WAV_SUCCESS)
		btr_splice_out_node(&fn->btrn);
	else {
		btr_remove_node(&fn->btrn);
		PARA_ERROR_LOG("%s\n", para_strerror(-ret));
	}
	return ret;
}

/** \cond doxygen_ignore */
const struct filter lsg_filter_cmd_com_wav_user_data = {
	.close = wav_close,
	.open = wav_open,
	.pre_monitor = wav_pre_monitor,
	.post_monitor = wav_post_monitor,
};
/** \endcond */