/*
 *
 *  BlueZ - Bluetooth protocol stack for Linux
 *
 *  Copyright (C) 2004-2007  Marcel Holtmann <marcel@holtmann.org>
 *
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

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

#include <sys/socket.h>
#include <sys/un.h>

#include <alsa/asoundlib.h>
#include <alsa/pcm_external.h>

#include <bluetooth/bluetooth.h>
#include <bluetooth/sco.h>

#include "ipc.h"

#define DBG(fmt, arg...)  printf("DEBUG: %s: " fmt "\n" , __FUNCTION__ , ## arg)

#ifndef SCO_TXBUFS
#define SCO_TXBUFS 0x03
#endif

#ifndef SCO_RXBUFS
#define SCO_RXBUFS 0x04
#endif

struct bluetooth_data {
	snd_pcm_ioplug_t io;
	snd_pcm_sframes_t hw_ptr;
	struct ipc_data_cfg cfg;	/* Bluetooth device config */
	int sock;			/* Daemon unix socket */
	uint8_t *buffer;		/* Transfer buffer */
	uint8_t count;			/* Transfer buffer counter */
};

static int bluetooth_start(snd_pcm_ioplug_t *io)
{
	DBG("io %p", io);

	return 0;
}

static int bluetooth_stop(snd_pcm_ioplug_t *io)
{
	DBG("io %p", io);

	return 0;
}

static snd_pcm_sframes_t bluetooth_pointer(snd_pcm_ioplug_t *io)
{
	struct bluetooth_data *data = io->private_data;

	DBG("io %p", io);

	DBG("hw_ptr=%lu", data->hw_ptr);

	return data->hw_ptr;
}

static int bluetooth_close(snd_pcm_ioplug_t *io)
{
	struct bluetooth_data *data = io->private_data;

	DBG("io %p", io);

	free(data);

	return 0;
}


static int bluetooth_prepare(snd_pcm_ioplug_t *io)
{
	struct bluetooth_data *data = io->private_data;

	DBG("Preparing with io->period_size = %lu, io->buffer_size = %lu", io->period_size, io->buffer_size);

	if (io->stream == SND_PCM_STREAM_PLAYBACK) {
		/* If not null for playback, xmms doesn't display time correctly */
		data->hw_ptr = 0;
	}
	else {
		/* ALSA library is really picky on the fact hw_ptr is not null. If it is, capture won't start */
		data->hw_ptr = io->period_size;
	}
	return 0;
}

static int bluetooth_hw_params(snd_pcm_ioplug_t *io, snd_pcm_hw_params_t *params)
{
	struct bluetooth_data *data = io->private_data;
	struct ipc_data_cfg cfg = data->cfg;
	uint32_t period_count = io->buffer_size / io->period_size;

	DBG("fd = %d, period_count = %d", cfg.fd, period_count);

	if(setsockopt(cfg.fd, SOL_SCO,
			io->stream == SND_PCM_STREAM_PLAYBACK ? SCO_TXBUFS : SCO_RXBUFS,
			&period_count,
			sizeof(period_count)) == 0) {
		return 0;
	} else if(setsockopt(cfg.fd, SOL_SCO,
			io->stream == SND_PCM_STREAM_PLAYBACK ? SO_SNDBUF : SO_RCVBUF,
			&period_count,
			sizeof(period_count)) == 0) {
                return 0;
        } else {
		SNDERR("Unable to set number of SCO buffers : please upgrade your Kernel !");
		return -EINVAL;
	}
}

static snd_pcm_sframes_t bluetooth_read(snd_pcm_ioplug_t *io,
					const snd_pcm_channel_area_t *areas,
					snd_pcm_uframes_t offset,
					snd_pcm_uframes_t size)
{
	struct bluetooth_data *data = io->private_data;
	struct ipc_data_cfg cfg = data->cfg;

	snd_pcm_sframes_t ret = 0;

	DBG("areas->step=%u, areas->first=%u, offset=%lu, size=%lu, io->nonblock=%u",
		areas->step, areas->first, offset, size, io->nonblock);

	if (data->count == 0) {
		int nrecv;

		nrecv = recv(cfg.fd, data->buffer, cfg.pkt_len,
			MSG_WAITALL | (io->nonblock ? MSG_DONTWAIT : 0 ));

		if (nrecv == cfg.pkt_len) {
			ret = 0;
			/* Increment hardware transmition pointer */
			data->hw_ptr = (data->hw_ptr + cfg.pkt_len / cfg.sample_size) % io->buffer_size;
		}
		else if (nrecv > 0) {
			ret = -EIO;
			SNDERR(strerror(-ret));
		}
		else if (nrecv == -1 && errno == EAGAIN) {
			ret = -EAGAIN;
		}
		else { /* nrecv < 0 */
			/* EPIPE means device underrun in ALSA world. But we mean we lost contact
			with server, so we have to find another error code */
			ret = (errno == EPIPE ? -EIO : -errno);
			SYSERR("Lost contact with headsetd");
		}
	}
	if(ret == 0) { /* Still ok, proceed */
		snd_pcm_uframes_t frames_to_write;
		unsigned char *buff;

		buff = (unsigned char *) areas->addr + (areas->first + areas->step * offset) / 8;

		if((data->count + cfg.sample_size * size) <= cfg.pkt_len)
			frames_to_write = size;
		else
			frames_to_write = (cfg.pkt_len - data->count) / cfg.sample_size;

		memcpy(buff, data->buffer + data->count, areas->step / 8 * frames_to_write);
		data->count += (areas->step / 8 * frames_to_write);
		data->count %= cfg.pkt_len;
		/* Return written frames count */
		ret = frames_to_write;
	}

	DBG("returning %d", (int)ret);
	return ret;
}

static snd_pcm_sframes_t bluetooth_write(snd_pcm_ioplug_t *io,
					const snd_pcm_channel_area_t *areas,
					snd_pcm_uframes_t offset,
					snd_pcm_uframes_t size)
{
	struct bluetooth_data *data = io->private_data;
	struct ipc_data_cfg cfg = data->cfg;
	snd_pcm_sframes_t ret = 0;
	snd_pcm_uframes_t frames_to_read;
	unsigned char *buff;

	DBG("areas->step=%u, areas->first=%u, offset=%lu, size=%lu, io->nonblock=%u",
		areas->step, areas->first, offset, size, io->nonblock);

	if ((data->count + cfg.sample_size * size) <= cfg.pkt_len)
		frames_to_read = size;
	else
		frames_to_read = (cfg.pkt_len - data->count) / cfg.sample_size;

	/* Ready for more data */
	buff = (unsigned char *) areas->addr + (areas->first + areas->step * offset) / 8;
	memcpy(data->buffer + data->count, buff, areas->step / 8 * frames_to_read);

	if ((data->count + areas->step / 8 * frames_to_read) == cfg.pkt_len) {
		int rsend;
		/* Actually send packet */
		rsend = send(cfg.fd, data->buffer, cfg.pkt_len, io->nonblock ? MSG_DONTWAIT : 0);
		if (rsend > 0) {
			/* Reset count pointer */
			data->count = 0;

			/* Increment hardware transmition pointer */
			data->hw_ptr = (data->hw_ptr + cfg.pkt_len / cfg.sample_size) % io->buffer_size;

			ret = frames_to_read;
		}
		else {
			/* EPIPE means device underrun in ALSA world. But we mean we lost contact
                           with server, so we have to find another error code */
			ret = (errno == EPIPE ? -EIO : -errno);
			if(errno == EPIPE)
				SYSERR("Lost contact with headsetd");
		}
	}
	else {
		/* Remember we have some frame in the pipe now */
		data->count += areas->step / 8 * frames_to_read;
		/* Ask for more */
		ret = frames_to_read;
	}

	DBG("returning %d", (int)ret);
	return ret;
}

static snd_pcm_ioplug_callback_t bluetooth_playback_callback = {
	.start		= bluetooth_start,
	.stop		= bluetooth_stop,
	.pointer	= bluetooth_pointer,
	.close		= bluetooth_close,
	.hw_params	= bluetooth_hw_params,
	.prepare	= bluetooth_prepare,
	.transfer	= bluetooth_write,
};

static snd_pcm_ioplug_callback_t bluetooth_capture_callback = {
	.start		= bluetooth_start,
	.stop		= bluetooth_stop,
	.pointer	= bluetooth_pointer,
	.close		= bluetooth_close,
	.hw_params	= bluetooth_hw_params,
	.prepare	= bluetooth_prepare,
	.transfer	= bluetooth_read,
};

#define ARRAY_NELEMS(a) (sizeof((a)) / sizeof((a)[0]))

static int bluetooth_hw_constraint(snd_pcm_ioplug_t *io)
{
	snd_pcm_access_t access_list[] = {
		SND_PCM_ACCESS_RW_INTERLEAVED,
		/* Mmap access is really useless fo this driver, but we
		 * support it because some pieces of software out there
		 * insist on using it */
		SND_PCM_ACCESS_MMAP_INTERLEAVED
	};
	unsigned int format_list[] = {
		SND_PCM_FORMAT_S16_LE
	};
	int err;

	err = snd_pcm_ioplug_set_param_list(io, SND_PCM_IOPLUG_HW_ACCESS,
					ARRAY_NELEMS(access_list), access_list);
	if (err < 0)
		return err;

	err = snd_pcm_ioplug_set_param_list(io, SND_PCM_IOPLUG_HW_FORMAT,
					ARRAY_NELEMS(format_list), format_list);
	if (err < 0)
		return err;

	err = snd_pcm_ioplug_set_param_minmax(io, SND_PCM_IOPLUG_HW_CHANNELS, 1, 1);
	if (err < 0)
		return err;

	err = snd_pcm_ioplug_set_param_minmax(io, SND_PCM_IOPLUG_HW_RATE, 8000, 8000);
	if (err < 0)
		return err;

	err = snd_pcm_ioplug_set_param_minmax(io, SND_PCM_IOPLUG_HW_PERIOD_BYTES, 48, 48);
	if (err < 0)
		return err;

	err = snd_pcm_ioplug_set_param_minmax(io, SND_PCM_IOPLUG_HW_PERIODS, 2, 200);
	if (err < 0)
		return err;

	return 0;
}

static int bluetooth_cfg(struct bluetooth_data *data)
{
	int res;
	int len = sizeof(struct ipc_packet) + sizeof(struct ipc_data_cfg);
	struct ipc_packet *pkt;

	DBG("Sending PKT_TYPE_CFG_REQ...");
	pkt = malloc(len);
	memset(pkt, 0, len);
	pkt->type = PKT_TYPE_CFG_REQ;
	pkt->role = PKT_ROLE_NONE;
	pkt->error = PKT_ERROR_NONE;
	res = send(data->sock, pkt, len, 0);
	if (res < 0)
		return errno;
	DBG("OK - %d bytes sent", res);

	DBG("Waiting for response...");

	memset(pkt, 0, len);
	res = recv(data->sock, pkt, len, 0);

	if (res < 0)
		return -errno;
	DBG("OK - %d bytes received", res);

	if (pkt->type != PKT_TYPE_CFG_RSP) {
		SNDERR("Unexpected packet type received: type = %d", pkt->type);
		return -EINVAL;
	}

	if (pkt->error != PKT_ERROR_NONE) {
		SNDERR("Error while configuring device: error = %d", pkt->error);
		return pkt->error;
	}

	if (pkt->length != sizeof(struct ipc_data_cfg)) {
		SNDERR("Error while configuring device: packet size doesn't match");
		return -EINVAL;
	}

	memcpy(&data->cfg, pkt->data, sizeof(struct ipc_data_cfg));

	DBG("Device configuration:");

	DBG("fd=%d, fd_opt=%u, channels=%u, pkt_len=%u, sample_size=%u, rate=%u",
		data->cfg.fd, data->cfg.fd_opt, data->cfg.channels,
		data->cfg.pkt_len, data->cfg.sample_size, data->cfg.rate);

	if (data->cfg.fd == -1) {
		SNDERR("Error while configuring device: could not acquire audio socket");
		return -EINVAL;
	}

	free(pkt);
	return 0;
}

static int bluetooth_init(struct bluetooth_data *data)
{
	int sk, err, id;
	struct sockaddr_un addr;

	if (!data)
		return -EINVAL;

	id = abs(getpid() * rand());

	sk = socket(PF_LOCAL, SOCK_DGRAM, 0);
	if (sk < 0) {
		SNDERR("Can't open socket");
		return -errno;
	}

	memset(&addr, 0, sizeof(addr));
	addr.sun_family = AF_UNIX;
	snprintf(addr.sun_path + 1, UNIX_PATH_MAX - 2, "%s/%d",
			IPC_SOCKET_NAME, id);

	DBG("Binding address: %s", addr.sun_path + 1);
	if (bind(sk, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
		SNDERR("Can't bind socket");
		close(sk);
		return -errno;
	}

	memset(&addr, 0, sizeof(addr));
	addr.sun_family = AF_UNIX;
	snprintf(addr.sun_path + 1, UNIX_PATH_MAX - 2, "%s", IPC_SOCKET_NAME);

	DBG("Connecting to address: %s", addr.sun_path + 1);
	if (connect(sk, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
		SNDERR("Can't connect socket");
		close(sk);
		return -errno;
	}

	data->sock = sk;

	if ((err = bluetooth_cfg(data)) < 0) {
		free(data);
		return err;
	}

	data->buffer = malloc(data->cfg.pkt_len);

	memset(data->buffer, 0, data->cfg.pkt_len);

	return 0;
}

SND_PCM_PLUGIN_DEFINE_FUNC(bluetooth)
{
//	snd_config_iterator_t iter, next;
	struct bluetooth_data *data;
	int err;

	DBG("Bluetooth PCM plugin blablabla (%s)",
		stream == SND_PCM_STREAM_PLAYBACK ? "Playback" : "Capture");

//	snd_config_for_each(iter, next, conf) {
//	}

	DBG("Initing Bluetooth...");
	data = malloc(sizeof(struct bluetooth_data));
	memset(data, 0, sizeof(struct bluetooth_data));
	err = bluetooth_init(data);
	if (err < 0)
		goto error;
	DBG("Done");

	data->io.version = SND_PCM_IOPLUG_VERSION;
	data->io.name = "Bluetooth Audio Device";
	data->io.mmap_rw =  0; /* No direct mmap communication */

	data->io.callback = stream == SND_PCM_STREAM_PLAYBACK ?
		&bluetooth_playback_callback : &bluetooth_capture_callback;
	data->io.poll_fd = data->cfg.fd;
	data->io.poll_events = stream == SND_PCM_STREAM_PLAYBACK ?
		POLLOUT : POLLIN;
	data->io.private_data = data;

	err = snd_pcm_ioplug_create(&data->io, name, stream, mode);
	if (err < 0)
		goto error;

	err = bluetooth_hw_constraint(&data->io);
	if (err < 0) {
		snd_pcm_ioplug_delete(&data->io);
		goto error;
	}

	*pcmp = data->io.pcm;

	return 0;

error:
	close(data->sock);
	free(data);

	return err;
}

SND_PCM_PLUGIN_SYMBOL(bluetooth);