/*
 * bluealsa-ctl.c
 * Copyright (c) 2016-2020 Arkadiusz Bokowy
 *
 * This file is a part of bluez-alsa.
 *
 * This project is licensed under the terms of the MIT license.
 *
 */

#include <ctype.h>
#include <errno.h>
#include <poll.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/param.h>

#include <alsa/asoundlib.h>
#include <alsa/control_external.h>
#include <bluetooth/bluetooth.h>
#include <dbus/dbus.h>

#include "shared/dbus-client.h"
#include "shared/defs.h"

enum ctl_elem_type {
	CTL_ELEM_TYPE_BATTERY,
	CTL_ELEM_TYPE_SWITCH,
	CTL_ELEM_TYPE_VOLUME,
};

struct ctl_elem {
	enum ctl_elem_type type;
	struct bt_dev *dev;
	struct ba_pcm *pcm;
	char name[44 /* internal ALSA constraint */ + 1];
	/* if true, element is a playback control */
	bool playback;
};

struct ctl_elem_update {
	char name[sizeof(((struct ctl_elem *)0)->name)];
	int event_mask;
};

struct bt_dev {
	char device_path[sizeof(((struct ba_pcm *)0)->device_path)];
	char rfcomm_path[sizeof(((struct ba_pcm *)0)->device_path)];
	char name[sizeof(((struct ctl_elem *)0)->name)];
	int battery_level;
	int mask;
};

struct bluealsa_ctl {
	snd_ctl_ext_t ext;

	/* D-Bus connection context */
	struct ba_dbus_ctx dbus_ctx;

	/* list of BT devices */
	struct bt_dev **dev_list;
	size_t dev_list_size;

	/* list of all BlueALSA PCMs */
	struct ba_pcm *pcm_list;
	size_t pcm_list_size;

	/* list of ALSA control elements */
	struct ctl_elem *elem_list;
	size_t elem_list_size;

	/* list of control element update events */
	struct ctl_elem_update *elem_update_list;
	size_t elem_update_list_size;
	size_t elem_update_event_i;

	/* if true, show battery meter */
	bool battery;

};

static int bluealsa_bt_dev_cmp(const void *p1, const void *p2) {
	const struct bt_dev *d1 = *(const struct bt_dev **)p1;
	const struct bt_dev *d2 = *(const struct bt_dev **)p2;
	return strcmp(d1->device_path, d2->device_path);
}

static int bluealsa_elem_cmp(const void *p1, const void *p2) {

	const struct ctl_elem *e1 = (const struct ctl_elem *)p1;
	const struct ctl_elem *e2 = (const struct ctl_elem *)p2;
	int rv;

	if ((rv = strcmp(e1->name, e2->name)) == 0)
		rv = bacmp(&e1->pcm->addr, &e2->pcm->addr);

	return rv;
}

static DBusMessage *bluealsa_dbus_get_property(DBusConnection *conn,
		const char *service, const char *path, const char *interface,
		const char *property, DBusError *error) {

	DBusMessage *msg;
	if ((msg = dbus_message_new_method_call(service, path,
					DBUS_INTERFACE_PROPERTIES, "Get")) == NULL)
		return NULL;

	DBusMessage *rep = NULL;

	if (!dbus_message_append_args(msg,
			DBUS_TYPE_STRING, &interface,
			DBUS_TYPE_STRING, &property,
			DBUS_TYPE_INVALID))
		goto fail;

	rep = dbus_connection_send_with_reply_and_block(conn, msg,
			DBUS_TIMEOUT_USE_DEFAULT, error);

fail:
	dbus_message_unref(msg);
	return rep;
}

/**
 * Get BT device ID number.
 *
 * @param ctl The BlueALSA controller context.
 * @param pcm BlueALSA PCM structure.
 * @return The device ID number, or -1 upon error. */
static int bluealsa_dev_get_id(struct bluealsa_ctl *ctl, const struct ba_pcm *pcm) {

	size_t i;
	for (i = 0; i < ctl->dev_list_size; i++)
		if (strcmp(ctl->dev_list[i]->device_path, pcm->device_path) == 0)
			return i + 1;

	return -1;
}

static int bluealsa_dev_fetch_name(struct bluealsa_ctl *ctl, struct bt_dev *dev) {

	DBusMessage *rep;
	DBusError err = DBUS_ERROR_INIT;
	if ((rep = bluealsa_dbus_get_property(ctl->dbus_ctx.conn, "org.bluez",
					dev->device_path, "org.bluez.Device1", "Alias", &err)) == NULL) {
		SNDERR("Couldn't get device name: %s", err.message);
		dbus_error_free(&err);
		return -1;
	}

	DBusMessageIter iter;
	DBusMessageIter iter_val;

	dbus_message_iter_init(rep, &iter);
	dbus_message_iter_recurse(&iter, &iter_val);

	const char *name;
	dbus_message_iter_get_basic(&iter_val, &name);
	*stpncpy(dev->name, name, sizeof(dev->name) - 1) = '\0';

	dbus_message_unref(rep);
	return 0;
}

static int bluealsa_dev_fetch_battery(struct bluealsa_ctl *ctl, struct bt_dev *dev) {

	DBusMessage *rep;
	if ((rep = bluealsa_dbus_get_property(ctl->dbus_ctx.conn, ctl->dbus_ctx.ba_service,
					dev->rfcomm_path, BLUEALSA_INTERFACE_RFCOMM, "Battery", NULL)) == NULL)
		return -1;

	DBusMessageIter iter;
	DBusMessageIter iter_val;

	dbus_message_iter_init(rep, &iter);
	dbus_message_iter_recurse(&iter, &iter_val);

	char battery;
	dbus_message_iter_get_basic(&iter_val, &battery);
	dev->battery_level = battery;

	dbus_message_unref(rep);
	return battery;
}

/**
 * Get BT device structure.
 *
 * @param ctl The BlueALSA controller context.
 * @param pcm BlueALSA PCM structure.
 * @return The BT device, or NULL upon error. */
static struct bt_dev *bluealsa_dev_get(struct bluealsa_ctl *ctl, const struct ba_pcm *pcm) {

	size_t i;
	for (i = 0; i < ctl->dev_list_size; i++)
		if (strcmp(ctl->dev_list[i]->device_path, pcm->device_path) == 0)
			return ctl->dev_list[i];

	/* If device is not cached yet, fetch data from
	 * the BlueZ via the B-Bus interface. */

	struct bt_dev **dev_list = ctl->dev_list;
	size_t size = ctl->dev_list_size;
	if ((dev_list = realloc(dev_list, (size + 1) * sizeof(*dev_list))) == NULL)
		return NULL;
	ctl->dev_list = dev_list;

	struct bt_dev *dev;
	if ((dev_list[size] = dev = malloc(sizeof(*dev))) == NULL)
		return NULL;
	ctl->dev_list_size++;

	strcpy(dev->device_path, pcm->device_path);
	sprintf(dev->rfcomm_path, "/org/bluealsa%.64s/rfcomm", &dev->device_path[10]);
	sprintf(dev->name, "%.2X:%.2X:%.2X:%.2X:%.2X:%.2X",
			pcm->addr.b[5], pcm->addr.b[4], pcm->addr.b[3],
			pcm->addr.b[2], pcm->addr.b[1], pcm->addr.b[0]);
	dev->battery_level = -1;

	/* Sort device list by an object path, so the bluealsa_dev_get_id() will
	 * return consistent IDs ordering in case of name duplications. */
	qsort(dev_list, ctl->dev_list_size, sizeof(*dev_list), bluealsa_bt_dev_cmp);

	bluealsa_dev_fetch_name(ctl, dev);
	return dev;
}

static int bluealsa_pcm_add(struct bluealsa_ctl *ctl, struct ba_pcm *pcm) {
	struct ba_pcm *tmp = ctl->pcm_list;
	if ((tmp = realloc(tmp, (ctl->pcm_list_size + 1) * sizeof(*tmp))) == NULL)
		return -1;
	memcpy(&tmp[ctl->pcm_list_size++], pcm, sizeof(*tmp));
	ctl->pcm_list = tmp;
	return 0;
}

static int bluealsa_pcm_remove(struct bluealsa_ctl *ctl, const char *path) {
	size_t i;
	for (i = 0; i < ctl->pcm_list_size; i++)
		if (strcmp(ctl->pcm_list[i].pcm_path, path) == 0)
			memcpy(&ctl->pcm_list[i], &ctl->pcm_list[--ctl->pcm_list_size], sizeof(*ctl->pcm_list));
	return 0;
}

/**
 * Update element name based on given string and PCM type.
 *
 * @param elem An address to the element structure.
 * @param name A string which should be used as a base for the element name.
 * @param id An unique ID number. If the ID is other than -1, it will be
 *   attached to the element name in order to prevent duplications. */
static void bluealsa_elem_set_name(struct ctl_elem *elem, const char *name, int id) {

	const int name_len = strlen(name);
	int len = sizeof(elem->name) - 16 - 1;
	char no[8] = "";

	if (id != -1) {
		sprintf(no, " #%u", id);
		len -= strlen(no);
	}

	if (elem->type == CTL_ELEM_TYPE_BATTERY) {
		len = MIN(len - 10, name_len);
		while (isspace(name[len - 1]))
			len--;
		sprintf(elem->name, "%.*s%s | Battery", len, name, no);
	}
	else {
		/* avoid name duplication by adding profile suffixes */
		if (elem->pcm->flags & BA_PCM_FLAG_PROFILE_A2DP) {
			len = MIN(len - 7, name_len);
			while (isspace(name[len - 1]))
				len--;
			sprintf(elem->name, "%.*s%s - A2DP", len, name, no);
		}
		if (elem->pcm->flags & BA_PCM_FLAG_PROFILE_SCO) {
			len = MIN(len - 6, name_len);
			while (isspace(name[len - 1]))
				len--;
			sprintf(elem->name, "%.*s%s - SCO", len, name, no);
		}
	}

	/* ALSA library determines the element type by checking it's
	 * name suffix. This feature is not well documented, though. */

	strcat(elem->name, elem->playback ? " Playback" : " Capture");

	switch (elem->type) {
	case CTL_ELEM_TYPE_SWITCH:
		strcat(elem->name, " Switch");
		break;
	case CTL_ELEM_TYPE_BATTERY:
	case CTL_ELEM_TYPE_VOLUME:
		strcat(elem->name, " Volume");
		break;
	}

}

static int bluealsa_create_elem_list(struct bluealsa_ctl *ctl) {

	if (ctl->pcm_list_size == 0)
		return 0;

	size_t count = 0;
	size_t i;

	for (i = 0; i < ctl->pcm_list_size; i++) {
		/* Every stream has two controls associated to
		 * itself - volume adjustment and mute switch. */
		count += 2;
		/* It is possible, that BT device battery level will be exposed via
		 * RFCOMM interface, so in order to account for a special "battery"
		 * element we have to increment our element counter by one. */
		count += 1;
	}

	struct ctl_elem *elem_list = ctl->elem_list;
	if ((elem_list = realloc(elem_list, count * sizeof(*elem_list))) == NULL)
		return -1;

	/* Clear device mask, so we can distinguish currently used and unused (old)
	 * device entries - we are not invalidating device list after PCM remove. */
	for (i = 0; i < ctl->dev_list_size; i++)
		ctl->dev_list[i]->mask = 0;

	count = 0;

	/* Construct control elements based on available PCMs. */
	for (i = 0; i < ctl->pcm_list_size; i++) {

		struct ba_pcm *pcm = &ctl->pcm_list[i];
		struct bt_dev *dev = bluealsa_dev_get(ctl, pcm);

		elem_list[count].type = CTL_ELEM_TYPE_VOLUME;
		elem_list[count].dev = dev;
		elem_list[count].pcm = pcm;
		elem_list[count].playback = pcm->flags & BA_PCM_FLAG_SINK;
		bluealsa_elem_set_name(&elem_list[count], dev->name, -1);
		count++;

		elem_list[count].type = CTL_ELEM_TYPE_SWITCH;
		elem_list[count].dev = dev;
		elem_list[count].pcm = pcm;
		elem_list[count].playback = pcm->flags & BA_PCM_FLAG_SINK;
		bluealsa_elem_set_name(&elem_list[count], dev->name, -1);
		count++;

		/* Try to add special "battery" element. */
		if (ctl->battery && dev->battery_level == -1 &&
				bluealsa_dev_fetch_battery(ctl, dev) != -1) {
			elem_list[count].type = CTL_ELEM_TYPE_BATTERY;
			elem_list[count].dev = dev;
			elem_list[count].pcm = pcm;
			elem_list[count].playback = true;
			bluealsa_elem_set_name(&elem_list[count], dev->name, -1);
			count++;
		}

	}

	/* Sort control elements alphabetically. */
	qsort(elem_list, count, sizeof(*elem_list), bluealsa_elem_cmp);

	/* Detect element name duplicates and annotate them with the
	 * consecutive device ID number - make ALSA library happy. */
	for (i = 0; i < count; i++) {

		char tmp[sizeof(elem_list[0].name)];
		bool duplicated = false;
		size_t ii;

		for (ii = i + 1; ii < count; ii++)
			if (strcmp(elem_list[i].name, elem_list[ii].name) == 0) {
				bluealsa_elem_set_name(&elem_list[ii], strcpy(tmp, elem_list[ii].dev->name),
						bluealsa_dev_get_id(ctl, elem_list[ii].pcm));
				duplicated = true;
			}

		if (duplicated)
			bluealsa_elem_set_name(&elem_list[i], strcpy(tmp, elem_list[i].dev->name),
					bluealsa_dev_get_id(ctl, elem_list[i].pcm));

	}

	ctl->elem_list = elem_list;
	ctl->elem_list_size = count;

	return count;
}

static void bluealsa_close(snd_ctl_ext_t *ext) {

	struct bluealsa_ctl *ctl = (struct bluealsa_ctl *)ext->private_data;
	size_t i;

	bluealsa_dbus_connection_ctx_free(&ctl->dbus_ctx);
	for (i = 0; i < ctl->dev_list_size; i++)
		free(ctl->dev_list[i]);
	free(ctl->dev_list);
	free(ctl->pcm_list);
	free(ctl->elem_list);
	free(ctl->elem_update_list);
	free(ctl);
}

static int bluealsa_elem_count(snd_ctl_ext_t *ext) {
	struct bluealsa_ctl *ctl = (struct bluealsa_ctl *)ext->private_data;
	return ctl->elem_list_size;
}

static int bluealsa_elem_list(snd_ctl_ext_t *ext, unsigned int offset, snd_ctl_elem_id_t *id) {
	struct bluealsa_ctl *ctl = (struct bluealsa_ctl *)ext->private_data;

	if (offset > ctl->elem_list_size)
		return -EINVAL;

	snd_ctl_elem_id_set_interface(id, SND_CTL_ELEM_IFACE_MIXER);
	snd_ctl_elem_id_set_name(id, ctl->elem_list[offset].name);

	return 0;
}

static snd_ctl_ext_key_t bluealsa_find_elem(snd_ctl_ext_t *ext, const snd_ctl_elem_id_t *id) {
	struct bluealsa_ctl *ctl = (struct bluealsa_ctl *)ext->private_data;

	unsigned int numid = snd_ctl_elem_id_get_numid(id);

	if (numid > 0 && numid <= ctl->elem_list_size)
		return numid - 1;

	const char *name = snd_ctl_elem_id_get_name(id);
	size_t i;

	for (i = 0; i < ctl->elem_list_size; i++)
		if (strcmp(ctl->elem_list[i].name, name) == 0)
			return i;

	return SND_CTL_EXT_KEY_NOT_FOUND;
}

static int bluealsa_get_attribute(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key,
		int *type, unsigned int *acc, unsigned int *count) {
	struct bluealsa_ctl *ctl = (struct bluealsa_ctl *)ext->private_data;

	if (key > ctl->elem_list_size)
		return -EINVAL;

	const struct ctl_elem *elem = &ctl->elem_list[key];
	const struct ba_pcm *pcm = elem->pcm;

	switch (elem->type) {
	case CTL_ELEM_TYPE_BATTERY:
		*acc = SND_CTL_EXT_ACCESS_READ;
		*type = SND_CTL_ELEM_TYPE_INTEGER;
		*count = 1;
		break;
	case CTL_ELEM_TYPE_SWITCH:
		*acc = SND_CTL_EXT_ACCESS_READWRITE;
		*type = SND_CTL_ELEM_TYPE_BOOLEAN;
		*count = pcm->channels;
		break;
	case CTL_ELEM_TYPE_VOLUME:
		*acc = SND_CTL_EXT_ACCESS_READWRITE;
		*type = SND_CTL_ELEM_TYPE_INTEGER;
		*count = pcm->channels;
		break;
	}

	return 0;
}

static int bluealsa_get_integer_info(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key,
		long *imin, long *imax, long *istep) {
	struct bluealsa_ctl *ctl = (struct bluealsa_ctl *)ext->private_data;

	if (key > ctl->elem_list_size)
		return -EINVAL;

	const struct ctl_elem *elem = &ctl->elem_list[key];
	const struct ba_pcm *pcm = elem->pcm;

	switch (elem->type) {
	case CTL_ELEM_TYPE_BATTERY:
		*imin = 0;
		*imax = 100;
		*istep = 1;
		break;
	case CTL_ELEM_TYPE_SWITCH:
		return -EINVAL;
	case CTL_ELEM_TYPE_VOLUME:
		if (pcm->flags & BA_PCM_FLAG_PROFILE_A2DP)
			*imax = 127;
		else if (pcm->flags & BA_PCM_FLAG_PROFILE_SCO)
			*imax = 15;
		else
			return -EINVAL;
		*imin = 0;
		*istep = 1;
		break;
	}

	return 0;
}

static int bluealsa_read_integer(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, long *value) {
	struct bluealsa_ctl *ctl = (struct bluealsa_ctl *)ext->private_data;

	if (key > ctl->elem_list_size)
		return -EINVAL;

	const struct ctl_elem *elem = &ctl->elem_list[key];
	const struct ba_pcm *pcm = elem->pcm;

	switch (elem->type) {
	case CTL_ELEM_TYPE_BATTERY:
		value[0] = elem->dev->battery_level;
		break;
	case CTL_ELEM_TYPE_SWITCH:
		value[0] = !pcm->volume.ch1_muted;
		if (pcm->channels == 2)
			value[1] = !pcm->volume.ch2_muted;
		break;
	case CTL_ELEM_TYPE_VOLUME:
		value[0] = pcm->volume.ch1_volume;
		if (pcm->channels == 2)
			value[1] = pcm->volume.ch2_volume;
		break;
	}

	return 0;
}

static int bluealsa_write_integer(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, long *value) {
	struct bluealsa_ctl *ctl = (struct bluealsa_ctl *)ext->private_data;

	if (key > ctl->elem_list_size)
		return -EINVAL;

	struct ctl_elem *elem = &ctl->elem_list[key];
	struct ba_pcm *pcm = elem->pcm;
	uint16_t old = pcm->volume.raw;

	switch (elem->type) {
	case CTL_ELEM_TYPE_BATTERY:
		/* this element should be read-only */
		return -EINVAL;
	case CTL_ELEM_TYPE_SWITCH:
		pcm->volume.ch1_muted = !value[0];
		if (pcm->channels == 2)
			pcm->volume.ch2_muted = !value[1];
		break;
	case CTL_ELEM_TYPE_VOLUME:
		pcm->volume.ch1_volume = value[0];
		if (pcm->channels == 2)
			pcm->volume.ch2_volume = value[1];
		break;
	}

	/* check whether update is required */
	if (pcm->volume.raw == old)
		return 0;

	if (!bluealsa_dbus_pcm_update(&ctl->dbus_ctx, pcm, BLUEALSA_PCM_VOLUME, NULL))
		return -ENOMEM;

	return 1;
}

static void bluealsa_subscribe_events(snd_ctl_ext_t *ext, int subscribe) {
	struct bluealsa_ctl *ctl = (struct bluealsa_ctl *)ext->private_data;

	if (subscribe) {
		bluealsa_dbus_connection_signal_match_add(&ctl->dbus_ctx, ctl->dbus_ctx.ba_service, NULL,
				BLUEALSA_INTERFACE_MANAGER, "PCMAdded", NULL);
		bluealsa_dbus_connection_signal_match_add(&ctl->dbus_ctx, ctl->dbus_ctx.ba_service, NULL,
				BLUEALSA_INTERFACE_MANAGER, "PCMRemoved", NULL);
		bluealsa_dbus_connection_signal_match_add(&ctl->dbus_ctx, ctl->dbus_ctx.ba_service, NULL,
				DBUS_INTERFACE_PROPERTIES, "PropertiesChanged", "arg0='"BLUEALSA_INTERFACE_PCM"'");
		bluealsa_dbus_connection_signal_match_add(&ctl->dbus_ctx, ctl->dbus_ctx.ba_service, NULL,
				DBUS_INTERFACE_PROPERTIES, "PropertiesChanged", "arg0='"BLUEALSA_INTERFACE_RFCOMM"'");
		bluealsa_dbus_connection_signal_match_add(&ctl->dbus_ctx, "org.bluez", NULL,
				DBUS_INTERFACE_PROPERTIES, "PropertiesChanged", "arg0='org.bluez.Device1'");
	}
	else
		bluealsa_dbus_connection_signal_match_clean(&ctl->dbus_ctx);

	dbus_connection_flush(ctl->dbus_ctx.conn);
}

static int bluealsa_elem_update_list_add(struct bluealsa_ctl *ctl,
		const char *elem_name, unsigned int mask) {

	struct ctl_elem_update *tmp = ctl->elem_update_list;
	if ((tmp = realloc(tmp, (ctl->elem_update_list_size + 1) * sizeof(*tmp))) == NULL)
		return -1;

	tmp[ctl->elem_update_list_size].event_mask = mask;
	*stpncpy(tmp[ctl->elem_update_list_size].name, elem_name,
			sizeof(tmp[ctl->elem_update_list_size].name) - 1) = '\0';

	ctl->elem_update_list = tmp;
	ctl->elem_update_list_size++;
	return 0;
}

#define bluealsa_event_elem_added(ctl, elem) \
	bluealsa_elem_update_list_add(ctl, elem, SND_CTL_EVENT_MASK_ADD)
#define bluealsa_event_elem_removed(ctl, elem) \
	bluealsa_elem_update_list_add(ctl, elem, SND_CTL_EVENT_MASK_REMOVE)
#define bluealsa_event_elem_updated(ctl, elem) \
	bluealsa_elem_update_list_add(ctl, elem, SND_CTL_EVENT_MASK_VALUE)

static dbus_bool_t bluealsa_dbus_msg_update_dev(const char *key,
		DBusMessageIter *variant, void *userdata, DBusError *error) {
	(void)error;

	struct bt_dev *dev = (struct bt_dev *)userdata;
	dev->mask = 0;

	if (strcmp(key, "Alias") == 0) {
		const char *alias;
		dbus_message_iter_get_basic(variant, &alias);
		*stpncpy(dev->name, alias, sizeof(dev->name) - 1) = '\0';
		dev->mask = SND_CTL_EVENT_MASK_ADD;
	}
	if (strcmp(key, "Battery") == 0) {
		char battery_level;
		dbus_message_iter_get_basic(variant, &battery_level);
		dev->mask = dev->battery_level == -1 ? SND_CTL_EVENT_MASK_ADD : SND_CTL_EVENT_MASK_VALUE;
		dev->battery_level = battery_level;
	}

	return TRUE;
}

static DBusHandlerResult bluealsa_dbus_msg_filter(DBusConnection *conn,
		DBusMessage *message, void *data) {
	struct bluealsa_ctl *ctl = (struct bluealsa_ctl *)data;
	(void)conn;

	if (dbus_message_get_type(message) != DBUS_MESSAGE_TYPE_SIGNAL)
		return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;

	DBusMessageIter iter;
	if (!dbus_message_iter_init(message, &iter))
		return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;

	const char *path = dbus_message_get_path(message);
	const char *interface = dbus_message_get_interface(message);
	const char *signal = dbus_message_get_member(message);
	size_t i;

	if (strcmp(interface, DBUS_INTERFACE_PROPERTIES) == 0 &&
			strcmp(signal, "PropertiesChanged") == 0) {

		const char *updated_interface;
		dbus_message_iter_get_basic(&iter, &updated_interface);
		dbus_message_iter_next(&iter);

		/* handle BlueZ device properties update */
		if (strcmp(updated_interface, "org.bluez.Device1") == 0)
			for (i = 0; i < ctl->elem_list_size; i++) {
				struct bt_dev *dev = ctl->elem_list[i].dev;
				if (strcmp(dev->device_path, path) == 0)
					bluealsa_dbus_message_iter_dict(&iter, NULL,
							bluealsa_dbus_msg_update_dev, dev);
				if (dev->mask & SND_CTL_EVENT_MASK_ADD)
					goto remove_add;
			}

		/* handle BlueALSA RFCOMM properties update */
		if (strcmp(updated_interface, BLUEALSA_INTERFACE_RFCOMM) == 0)
			for (i = 0; i < ctl->elem_list_size; i++) {
				struct bt_dev *dev = ctl->elem_list[i].dev;
				if (strcmp(dev->rfcomm_path, path) == 0) {
					bluealsa_dbus_message_iter_dict(&iter, NULL,
							bluealsa_dbus_msg_update_dev, dev);
					if (dev->mask & SND_CTL_EVENT_MASK_ADD)
						goto remove_add;
					if (dev->mask & SND_CTL_EVENT_MASK_VALUE)
						bluealsa_event_elem_updated(ctl, ctl->elem_list[i].name);
				}
			}

		/* handle BlueALSA PCM properties update */
		if (strcmp(updated_interface, BLUEALSA_INTERFACE_PCM) == 0)
			for (i = 0; i < ctl->elem_list_size; i++) {
				struct ctl_elem *elem = &ctl->elem_list[i];
				if (strcmp(elem->pcm->pcm_path, path) == 0) {
					if (elem->type == CTL_ELEM_TYPE_BATTERY) {
						bluealsa_dbus_message_iter_dict(&iter, NULL,
								bluealsa_dbus_msg_update_dev, elem->dev);
						if (elem->dev->mask & SND_CTL_EVENT_MASK_ADD)
							goto remove_add;
						if (elem->dev->mask & SND_CTL_EVENT_MASK_VALUE)
							bluealsa_event_elem_updated(ctl, ctl->elem_list[i].name);
					}
					else {
						bluealsa_dbus_message_iter_get_pcm_props(&iter, NULL, elem->pcm);
						bluealsa_event_elem_updated(ctl, elem->name);
					}
				}
			}

	}

	if (strcmp(interface, BLUEALSA_INTERFACE_MANAGER) == 0) {

		if (strcmp(signal, "PCMAdded") == 0) {
			struct ba_pcm pcm;
			bluealsa_dbus_message_iter_get_pcm(&iter, NULL, &pcm);
			bluealsa_pcm_add(ctl, &pcm);
			goto remove_add;
		}

		if (strcmp(signal, "PCMRemoved") == 0) {
			const char *path;
			dbus_message_iter_get_basic(&iter, &path);
			bluealsa_pcm_remove(ctl, path);
			goto remove_add;
		}

	}

	return DBUS_HANDLER_RESULT_HANDLED;

remove_add: {

	/* During a PCM name change, new PCM insertion and/or deletion, the name
	 * of all control elements might have change, because of optional unique
	 * device ID suffix - for more information see the bluealsa_elem_set_name()
	 * function. So, in such a case we will simply remove all old controllers
	 * and add new ones in order to update potential name changes. */

	for (i = 0; i < ctl->elem_list_size; i++)
		bluealsa_event_elem_removed(ctl, ctl->elem_list[i].name);

	bluealsa_create_elem_list(ctl);

	for (i = 0; i < ctl->elem_list_size; i++)
		bluealsa_event_elem_added(ctl, ctl->elem_list[i].name);

	return DBUS_HANDLER_RESULT_HANDLED;
}}

static int bluealsa_read_event(snd_ctl_ext_t *ext, snd_ctl_elem_id_t *id, unsigned int *event_mask) {
	struct bluealsa_ctl *ctl = ext->private_data;

	if (ctl->elem_update_list_size) {

		snd_ctl_elem_id_set_interface(id, SND_CTL_ELEM_IFACE_MIXER);
		snd_ctl_elem_id_set_name(id, ctl->elem_update_list[ctl->elem_update_event_i].name);
		*event_mask = ctl->elem_update_list[ctl->elem_update_event_i].event_mask;

		if (++ctl->elem_update_event_i == ctl->elem_update_list_size) {
			ctl->elem_update_list_size = 0;
			ctl->elem_update_event_i = 0;
		}

		return 1;
	}

	struct pollfd fds[8];
	nfds_t nfds = ARRAYSIZE(fds);

	/* It seems that ALSA does not call .poll_revents() callback, but we need
	 * to feed poll() events back to our dispatching function. Since ALSA is
	 * not cooperating, we will call poll() once more by ourself and receive
	 * required event flags. If someday ALSA will be so kind to actually call
	 * .poll_revents(), this code should remain as a backward compatibility. */
	bluealsa_dbus_connection_poll_fds(&ctl->dbus_ctx, fds, &nfds);
	poll(fds, nfds, 0);
	bluealsa_dbus_connection_poll_dispatch(&ctl->dbus_ctx, fds, nfds);

	/* Dispatch incoming D-Bus messages/signals. The actual dispatching
	 * will be done in the bluealsa_dbus_msg_filter() callback function. */
	while (dbus_connection_dispatch(ctl->dbus_ctx.conn) == DBUS_DISPATCH_DATA_REMAINS)
		continue;

	if (ctl->elem_update_list_size)
		return bluealsa_read_event(ext, id, event_mask);
	return -EAGAIN;
}

static int bluealsa_poll_descriptors_count(snd_ctl_ext_t *ext) {
	struct bluealsa_ctl *ctl = ext->private_data;

	nfds_t dbus_nfds = 0;
	bluealsa_dbus_connection_poll_fds(&ctl->dbus_ctx, NULL, &dbus_nfds);

	return dbus_nfds;
}

static int bluealsa_poll_descriptors(snd_ctl_ext_t *ext, struct pollfd *pfd,
		unsigned int nfds) {
	struct bluealsa_ctl *ctl = ext->private_data;

	nfds_t dbus_nfds = nfds;
	if (!bluealsa_dbus_connection_poll_fds(&ctl->dbus_ctx, pfd, &dbus_nfds))
		return -EINVAL;

	return dbus_nfds;
}

static int bluealsa_poll_revents(snd_ctl_ext_t *ext, struct pollfd *pfd,
		unsigned int nfds, unsigned short *revents) {
	struct bluealsa_ctl *ctl = ext->private_data;

	if (bluealsa_dbus_connection_poll_dispatch(&ctl->dbus_ctx, pfd, nfds))
		*revents = POLLIN;
	else
		*revents = 0;

	return 0;
}

static const snd_ctl_ext_callback_t bluealsa_snd_ctl_ext_callback = {
	.close = bluealsa_close,
	.elem_count = bluealsa_elem_count,
	.elem_list = bluealsa_elem_list,
	.find_elem = bluealsa_find_elem,
	.get_attribute = bluealsa_get_attribute,
	.get_integer_info = bluealsa_get_integer_info,
	.read_integer = bluealsa_read_integer,
	.write_integer = bluealsa_write_integer,
	.subscribe_events = bluealsa_subscribe_events,
	.read_event = bluealsa_read_event,
	.poll_descriptors_count = bluealsa_poll_descriptors_count,
	.poll_descriptors = bluealsa_poll_descriptors,
	.poll_revents = bluealsa_poll_revents,
};

SND_CTL_PLUGIN_DEFINE_FUNC(bluealsa) {
	(void)root;

	snd_config_iterator_t i, next;
	DBusError err = DBUS_ERROR_INIT;
	const char *service = BLUEALSA_SERVICE;
	const char *battery = "no";
	struct bluealsa_ctl *ctl;
	int ret;

	snd_config_for_each(i, next, conf) {
		snd_config_t *n = snd_config_iterator_entry(i);

		const char *id;
		if (snd_config_get_id(n, &id) < 0)
			continue;

		if (strcmp(id, "comment") == 0 ||
				strcmp(id, "type") == 0 ||
				strcmp(id, "hint") == 0)
			continue;

		if (strcmp(id, "service") == 0) {
			if (snd_config_get_string(n, &service) < 0) {
				SNDERR("Invalid type for %s", id);
				return -EINVAL;
			}
			continue;
		}
		if (strcmp(id, "battery") == 0) {
			if (snd_config_get_string(n, &battery) < 0) {
				SNDERR("Invalid type for %s", id);
				return -EINVAL;
			}
			continue;
		}

		SNDERR("Unknown field %s", id);
		return -EINVAL;
	}

	if ((ctl = calloc(1, sizeof(*ctl))) == NULL)
		return -ENOMEM;

	ctl->battery = strcmp(battery, "yes") == 0;

	dbus_threads_init_default();

	if (!bluealsa_dbus_connection_ctx_init(&ctl->dbus_ctx, service, &err)) {
		SNDERR("Couldn't initialize D-Bus context: %s", err.message);
		ret = -ENOMEM;
		goto fail;
	}

	if (!dbus_connection_add_filter(ctl->dbus_ctx.conn, bluealsa_dbus_msg_filter, ctl, NULL)) {
		SNDERR("Couldn't add D-Bus filter: %s", strerror(ENOMEM));
		ret = -ENOMEM;
		goto fail;
	}

	if (!bluealsa_dbus_get_pcms(&ctl->dbus_ctx, &ctl->pcm_list, &ctl->pcm_list_size, &err)) {
		SNDERR("Couldn't get BlueALSA PCM list: %s", err.message);
		ret = -ENODEV;
		goto fail;
	}

	if (bluealsa_create_elem_list(ctl) == -1) {
		SNDERR("Couldn't create control elements: %s", strerror(errno));
		ret = -errno;
		goto fail;
	}

	ctl->ext.version = SND_CTL_EXT_VERSION;
	ctl->ext.card_idx = 0;
	strncpy(ctl->ext.id, "bluealsa", sizeof(ctl->ext.id) - 1);
	strncpy(ctl->ext.driver, "BlueALSA", sizeof(ctl->ext.driver) - 1);
	strncpy(ctl->ext.name, "BlueALSA", sizeof(ctl->ext.name) - 1);
	strncpy(ctl->ext.longname, "Bluetooth Audio Hub Controller", sizeof(ctl->ext.longname) - 1);
	strncpy(ctl->ext.mixername, "BlueALSA Plugin", sizeof(ctl->ext.mixername) - 1);

	ctl->ext.callback = &bluealsa_snd_ctl_ext_callback;
	ctl->ext.private_data = ctl;
	ctl->ext.poll_fd = -1;

	if ((ret = snd_ctl_ext_create(&ctl->ext, name, mode)) < 0)
		goto fail;

	*handlep = ctl->ext.handle;
	return 0;

fail:
	bluealsa_dbus_connection_ctx_free(&ctl->dbus_ctx);
	dbus_error_free(&err);
	free(ctl);
	return ret;
}

SND_CTL_PLUGIN_SYMBOL(bluealsa)
