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

/** \file oss_mix.c The OSS mixer plugin. */

#include <sys/soundcard.h>
#include <sys/ioctl.h>

#include "para.h"
#include "error.h"
#include "mix.h"
#include "fd.h"
#include "string.h"

struct oss_mixer_channel {
	const char *name;
	int id;
};

static const struct oss_mixer_channel channels[] = {
	{.name = "volume", .id = SOUND_MIXER_VOLUME},
	{.name = "bass", .id = SOUND_MIXER_BASS},
	{.name = "treble", .id = SOUND_MIXER_TREBLE},
	{.name = "synth", .id = SOUND_MIXER_SYNTH},
	{.name = "pcm", .id = SOUND_MIXER_PCM},
	{.name = "speaker", .id = SOUND_MIXER_SPEAKER},
	{.name = "line", .id = SOUND_MIXER_LINE},
	{.name = "mic", .id = SOUND_MIXER_MIC},
	{.name = "cd", .id = SOUND_MIXER_CD},
	{.name = "imix", .id = SOUND_MIXER_IMIX},
	{.name = "altpcm", .id = SOUND_MIXER_ALTPCM},
	{.name = "reclev", .id = SOUND_MIXER_RECLEV},
	{.name = "igain", .id = SOUND_MIXER_IGAIN},
	{.name = "ogain", .id = SOUND_MIXER_OGAIN},
};

/** Iterate over all defined mixer channels. */
#define FOR_EACH_CHANNEL(i) for ((i) = 0; (i) < ARRAY_SIZE(channels); (i)++)

struct mixer_handle {
	int fd;
	int id;
};

static int oss_mix_open(const char *dev, struct mixer_handle **handle)
{
	int ret;
	struct mixer_handle *h;

	*handle = NULL;
	if (!dev)
		dev = "/dev/mixer";
	PARA_INFO_LOG("opening %s\n", dev);
	ret = para_open(dev, O_RDWR, 42);
	if (ret < 0) {
		PARA_ERROR_LOG("could not open %s\n", dev);
		return ret;
	}
	h = alloc(sizeof(*h));
	h->fd = ret;
	*handle = h;
	return 1;
}

static char *oss_mix_get_channels(__a_unused struct mixer_handle *handle)
{
	int i;
	char *list = NULL;

	FOR_EACH_CHANNEL(i) {
		const char *name = channels[i].name;
		char *tmp = list;
		list = make_message("%s%s%s",
			list? list : "",
			list? ", " : "",
			name);
		free(tmp);
	}
	return list;
}

static int oss_mix_set_channel(struct mixer_handle *handle,
		const char *mixer_channel)
{
	int i;

	if (!mixer_channel) {
		handle->id = SOUND_MIXER_VOLUME; /* default */
		return 0;
	}
	FOR_EACH_CHANNEL(i) {
		if (strcasecmp(channels[i].name, mixer_channel))
			continue;
		handle->id = i;
		return 1;
	}
	return -E_BAD_CHANNEL;
}

static int oss_mix_get(const struct mixer_handle *handle)
{
	int val, fd = handle->fd, id = handle->id;

	if (ioctl(fd, MIXER_READ(id), &val) < 0)
		return -ERRNO_TO_PARA_ERROR(errno);
	/* take the mean value of left and right */
	return (val % 256 + (val >> 8)) / 2;
}

static int oss_mix_set(struct mixer_handle *handle, int val)
{
	int fd = handle->fd, id = handle->id, tmp = (val << 8) + val;

	if (ioctl(fd, MIXER_WRITE(id), &tmp) < 0)
		return -ERRNO_TO_PARA_ERROR(errno);
	return 1;
}

static void oss_mix_close(struct mixer_handle *h)
{
	if (h && h->fd >= 0)
		close(h->fd);
	free(h);
}

/** The mixer operations for the OSS mixer. */
const struct mixer oss_mixer = {
	.name = "oss",
	.open = oss_mix_open,
	.get_channels = oss_mix_get_channels,
	.set_channel = oss_mix_set_channel,
	.close = oss_mix_close,
	.get = oss_mix_get,
	.set = oss_mix_set
};