/*
 * Media device discovery library
 *
 * Copyright (C) 2012 Ideas on board SPRL
 *
 * Contact: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
 *
 * This program 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 program 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 program. If not, see <http://www.gnu.org/licenses/>.
 */

#define HAVE_LIBUDEV

#include <ctype.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <linux/videodev2.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>

#ifdef HAVE_LIBUDEV
#include <libudev.h>
#endif

#include <mediactl/mediactl.h>

#include "media-enumerate.h"

struct media_enumerate {
	unsigned int refcount;

	char **syspaths;
	struct media_device **devices;
	unsigned int devices_count;
	unsigned int devices_max;

#ifdef HAVE_LIBUDEV
	struct udev *udev;
#endif
};

static int media_enumerate_add_device(struct media_enumerate *media_enum,
				      const char *syspath,
				      struct media_device *media)
{
	if (media_enum->devices_count == media_enum->devices_max) {
		struct media_device **devices;
		char **syspaths;
		unsigned int count;

		count = media_enum->devices_max * 2;
		count = count < 16 ? 16 : count;

		devices = realloc(media_enum->devices, count * sizeof *devices);
		if (devices == NULL)
			return -ENOMEM;
		media_enum->devices = devices;

		syspaths = realloc(media_enum->syspaths, count * sizeof *syspaths);
		if (syspaths == NULL)
			return -ENOMEM;
		media_enum->syspaths = syspaths;

		media_enum->devices_max = count;
	}

	media_enum->devices[media_enum->devices_count] = media;
	media_enum->syspaths[media_enum->devices_count] = strdup(syspath);
	media_enum->devices_count++;

	return 0;
}

typedef int(*media_enumerate_callback)(struct media_enumerate *, const char *,
				       const char *, dev_t);

enum media_enumerate_bus_type {
	BUS_TYPE_UNKNOWN,
	BUS_TYPE_PCI,
	BUS_TYPE_USB,
};

static enum media_enumerate_bus_type
media_enumerate_get_physical_bus(const char *syspath)
{
	char *modalias;
	char type[4];
	int ret;
	int fd;

	modalias = malloc(strlen(syspath) + 10);
	if (modalias == NULL)
		return BUS_TYPE_UNKNOWN;

	sprintf(modalias, "%s/modalias", syspath);
	fd = open(modalias, O_RDONLY);
	free(modalias);

	if (fd == -1)
		return BUS_TYPE_UNKNOWN;

	ret = read(fd, type, 3);
	close(fd);

	if (ret != 3)
		return BUS_TYPE_UNKNOWN;

	type[3] = '\0';

	if (!strcmp(type, "pci"))
		return BUS_TYPE_PCI;
	else if (!strcmp(type, "usb"))
		return BUS_TYPE_USB;
	else
		return BUS_TYPE_UNKNOWN;
}

static char *media_enumerate_get_physical_parent(const char *syspath)
{
	enum media_enumerate_bus_type bus_type;
	char *phys;
	char *p;

	phys = realpath(syspath, NULL);
	if (phys == NULL)
		return NULL;

	p = strstr(phys, "media");
	if (p)
		*(p - 1) = '\0';
	p = strstr(phys, "sound");
	if (p)
		*(p - 1) = '\0';
	p = strstr(phys, "video4linux");
	if (p)
		*(p - 1) = '\0';

	bus_type = media_enumerate_get_physical_bus(phys);

	switch (bus_type) {
	case BUS_TYPE_PCI:
		/* Remove the PCI function from the path if present. */
		p = strrchr(phys, '.');
		if (p)
			*p = '\0';
		break;
	case BUS_TYPE_USB:
		/* Remove the USB interface from the path if present. */
		p = strrchr(phys, '/');
		if (p && strchr(p, ':'))
			*p = '\0';
		break;
	default:
		break;
	}

	return phys;
}

#ifdef HAVE_LIBUDEV

/* -----------------------------------------------------------------------------
 * udev helpers
 */

static int media_enumerate_udev_scan_one(struct media_enumerate *media_enum,
					 const char *syspath,
					 media_enumerate_callback callback)
{
	struct udev_device *dev;
	const char *devnode;
	char *devpath = NULL;
	dev_t devnum;
	int ret = -ENODEV;

	dev = udev_device_new_from_syspath(media_enum->udev, syspath);
	if (dev == NULL)
		return -ENODEV;

	devnode = udev_device_get_devnode(dev);
	if (devnode == NULL)
		goto done;

	devpath = media_enumerate_get_physical_parent(syspath);
	if (devpath == NULL)
		goto done;

	devnum = udev_device_get_devnum(dev);
	ret = callback(media_enum, devpath, devnode, devnum);

done:
	udev_device_unref(dev);
	free(devpath);
	return ret;
}

static int media_enumerate_udev_scan(struct media_enumerate *media_enum,
				     const char *subsystem, const char *type,
				     media_enumerate_callback callback)
{
	struct udev_enumerate *udev_enum = NULL;
	struct udev_list_entry *devs;
	struct udev_list_entry *dev;
	unsigned int len;
	int ret;

	udev_enum = udev_enumerate_new(media_enum->udev);
	if (udev_enum == NULL) {
		ret = -ENOMEM;
		goto done;
	}

	ret = udev_enumerate_add_match_subsystem(udev_enum, subsystem);
	if (ret < 0)
		goto done;

	ret = udev_enumerate_scan_devices(udev_enum);
	if (ret < 0)
		goto done;

	devs = udev_enumerate_get_list_entry(udev_enum);
	if (devs == NULL)
		goto done;

	len = strlen(type);

	udev_list_entry_foreach(dev, devs) {
		const char *syspath;
		const char *p;

		syspath = udev_list_entry_get_name(dev);

		p = strrchr(syspath, '/');
		if (p == NULL || strncmp(p + 1, type, len))
			continue;

		media_enumerate_udev_scan_one(media_enum, syspath, callback);
	}

	ret = 0;

done:
	udev_enumerate_unref(udev_enum);
	return ret;
}

#else

/* -----------------------------------------------------------------------------
 * sysfs helpers
 */

static int
media_enumerate_sysfs_scan_one(struct media_enumerate *media_enum,
			       const char *sysbase, const char *prefix, int idx,
			       media_enumerate_callback callback)
{
	unsigned int major;
	unsigned int minor;
	struct stat devstat;
	unsigned int len;
	char *devname;
	char *devpath;
	char dev[20];
	char *end;
	int ret;
	int fd;

	/* Read the device major and minor from sysfs. */
	len = strlen(sysbase) + strlen(prefix) + 17;
	devname = malloc(len);
	if (devname == NULL)
		return -ENOMEM;

	sprintf(devname, "%s/%s%u", sysbase, prefix, idx);
	devpath = media_enumerate_get_physical_parent(devname);
	if (devpath == NULL)
		goto done;

	sprintf(devname, "%s/%s%u/dev", sysbase, prefix, idx);
	fd = open(devname, O_RDONLY);
	if (fd == -1) {
		ret = -ENODEV;
		goto done;
	}

	ret = read(fd, dev, sizeof dev - 1);
	close(fd);
	if (ret < 0) {
		ret = -ENODEV;
		goto done;
	}

	dev[ret] = '\0';
	major = strtoul(dev, &end, 10);
	if (*end != ':') {
		ret = -ENODEV;
		goto done;
	}

	minor = strtoul(end + 1, &end, 10);
	if (!isspace(*end) && end != '\0') {
		ret = -ENODEV;
		goto done;
	}

	/* Verify that the device node exists. udev might have reordered the
	 * device nodes, make sure the major/minor match as a sanity check.
	 */
	if (!strcmp(prefix, "controlC"))
		sprintf(devname, "/dev/snd/%s%u", prefix, idx);
	else
		sprintf(devname, "/dev/%s%u", prefix, idx);

	ret = stat(devname, &devstat);
	if (ret < 0) {
		ret = -ENODEV;
		goto done;
	}

	if (major(devstat.st_rdev) != major || minor(devstat.st_rdev) != minor) {
		ret = -ENODEV;
		goto done;
	}

	ret = callback(media_enum, devpath, devname, makedev(major, minor));

done:
	free(devname);
	free(devpath);
	return ret;
}

static int
media_enumerate_sysfs_scan(struct media_enumerate *media_enum,
			   const char *sysbase, const char *prefix,
			   media_enumerate_callback callback)
{
	struct dirent *ent;
	unsigned int len;
	char *end;
	DIR *dir;

	len = strlen(prefix);

	dir = opendir(sysbase);
	if (dir == NULL)
		return -ENODEV;

	while ((ent = readdir(dir)) != NULL) {
		unsigned int idx;

		if (strncmp(ent->d_name, prefix, len))
			continue;

		idx = strtoul(ent->d_name + len, &end, 10);
		if (*end != '\0')
			continue;

		media_enumerate_sysfs_scan_one(media_enum, sysbase, prefix, idx,
					       callback);
	}

	closedir(dir);

	return 0;
}

#endif

/* -----------------------------------------------------------------------------
 * Media devices enumeration
 */

static int media_enumerate_match_one_media(struct media_enumerate *media_enum,
					   const char *syspath, const char *devname,
					   dev_t devnum __attribute__((__unused__)))
{
	struct media_device *media;
	int ret;

	media = media_device_new(devname);
	if (media == NULL)
		return -ENODEV;

	ret = media_device_enumerate(media);
	if (ret < 0) {
		media_device_unref(media);
		return -ENODEV;
	}

	return media_enumerate_add_device(media_enum, syspath, media);
}

static int media_enumerate_scan_media(struct media_enumerate *media_enum)
{
#ifdef HAVE_LIBUDEV
	return media_enumerate_udev_scan(media_enum, "media", "media",
					 media_enumerate_match_one_media);
#else
	return media_enumerate_sysfs_scan(media_enum, "/sys/bus/media/devices",
					  "media", media_enumerate_match_one_media);
#endif	/* HAVE_LIBUDEV */
}

/* -----------------------------------------------------------------------------
 * Video devices enumeration
 */

static int media_enumerate_match_one_video(struct media_enumerate *media_enum,
					   const char *syspath,
					   const char *devname, dev_t devnum)
{
	struct media_entity_desc entity;
	struct media_device_info info;
	struct v4l2_capability cap;
	struct media_device *media;
	unsigned int i, j;
	int ret;
	int fd;

	/* Verify whether the video device node is part of an already enumerated
	 * media device.
	 */
	for (i = 0; i < media_enum->devices_count; ++i) {
		unsigned int nents;

		media = media_enum->devices[i];
		nents = media_get_entities_count(media);

		for (j = 0; j < nents; ++j) {
			struct media_entity *entity = media_get_entity(media, j);
			const struct media_entity_desc *info = media_entity_get_info(entity);
			dev_t dev;

			if (info->type != MEDIA_ENT_T_DEVNODE_V4L)
				continue;

			dev = makedev(info->v4l.major, info->v4l.minor);
			if (dev == devnum)
				return 0;
		}
	}

	fd = open(devname, O_RDWR);
	if (fd < 0)
		return -ENODEV;

	memset(&cap, 0, sizeof cap);
	ret = ioctl(fd, VIDIOC_QUERYCAP, &cap);
	close(fd);

	if (ret < 0)
		return -ENODEV;

	memset(&info, 0, sizeof info);
	memcpy(info.driver, cap.driver, sizeof info.driver);
	memcpy(info.model, cap.card, sizeof info.model);
	memcpy(info.bus_info, cap.bus_info, sizeof info.bus_info);
	info.driver_version = cap.version;

	media = media_device_new_emulated(&info);
	if (media == NULL)
		return -ENOMEM;

	memset(&entity, 0, sizeof entity);
	memcpy(entity.name, cap.card, sizeof entity.name);
	entity.type = MEDIA_ENT_T_DEVNODE_V4L;
	entity.flags = MEDIA_ENT_FL_DEFAULT;
	entity.v4l.major = major(devnum);
	entity.v4l.minor = minor(devnum);

	ret = media_device_add_entity(media, &entity, devname);
	if (ret < 0) {
		media_device_unref(media);
		return ret;
	}

	return media_enumerate_add_device(media_enum, syspath, media);
}

static int media_enumerate_scan_video(struct media_enumerate *media_enum)
{
#ifdef HAVE_LIBUDEV
	return media_enumerate_udev_scan(media_enum, "video4linux", "video",
					 media_enumerate_match_one_video);
#else
	return media_enumerate_sysfs_scan(media_enum, "/sys/class/video4linux",
					  "video", media_enumerate_match_one_video);
#endif	/* HAVE_LIBUDEV */
}

/* -----------------------------------------------------------------------------
 * Audio devices enumeration
 */

static int media_enumerate_match_one_audio(struct media_enumerate *media_enum,
					   const char *syspath, const char *devname,
					   dev_t devnum __attribute__((__unused__)))
{
	struct media_entity_desc entity;
	struct media_device *parent = NULL;
	struct media_device *media;
	unsigned int card;
	unsigned int i, j;
	char *endp;

	/* Verify whether the sound card is part of an already enumerated media
	 * device.
	 */
	card = strtoul(strrchr(devname, '/') + strlen("/controlC"), &endp, 10);
	if (*endp != '\0')
		return -EINVAL;

	for (i = 0; i < media_enum->devices_count; ++i) {
		unsigned int nents;

		media = media_enum->devices[i];
		nents = media_get_entities_count(media);

		if (!strcmp(media_enum->syspaths[i], syspath))
			parent = media;

		for (j = 0; j < nents; ++j) {
			struct media_entity *entity = media_get_entity(media, j);
			const struct media_entity_desc *info = media_entity_get_info(entity);

			if (info->type != MEDIA_ENT_T_DEVNODE_ALSA)
				continue;

			if (info->alsa.card == card)
				return 0;
		}
	}

	if (!parent)
		return 0;

	memset(&entity, 0, sizeof entity);
	entity.type = MEDIA_ENT_T_DEVNODE_ALSA;
	entity.flags = MEDIA_ENT_FL_DEFAULT;
	snprintf(entity.name, sizeof entity.name, "ALSA %u/%u/%u", card, 0, 0);
	entity.alsa.card = card;
	entity.alsa.device = 0;
	entity.alsa.subdevice = 0;

	return media_device_add_entity(parent, &entity, devname);
}

static int media_enumerate_scan_audio(struct media_enumerate *media_enum)
{
#ifdef HAVE_LIBUDEV
	return media_enumerate_udev_scan(media_enum, "sound", "control",
					 media_enumerate_match_one_audio);
#else
	return media_enumerate_sysfs_scan(media_enum, "/sys/class/sound",
					  "controlC", media_enumerate_match_one_audio);
#endif	/* HAVE_LIBUDEV */
}

/* -------------------------------------------------------------------------- */

struct media_enumerate *media_enumerate_new(void)
{
	struct media_enumerate *media_enum;

	media_enum = calloc(1, sizeof *media_enum);
	if (media_enum == NULL)
		return NULL;

	media_enum->refcount = 1;

#ifdef HAVE_LIBUDEV
	media_enum->udev = udev_new();
	if (media_enum->udev == NULL) {
		printf("Unable to get udev context\n");
		media_enumerate_unref(media_enum);
		return NULL;
	}
#endif

	return media_enum;
}

struct media_enumerate *media_enumerate_ref(struct media_enumerate *media_enum)
{
	media_enum->refcount++;
	return media_enum;
}

void media_enumerate_unref(struct media_enumerate *media_enum)
{
	unsigned int i;

	media_enum->refcount--;
	if (media_enum->refcount > 0)
		return;

	for (i = 0; i < media_enum->devices_count; ++i) {
		media_device_unref(media_enum->devices[i]);
		free(media_enum->syspaths[i]);
	}

#ifdef HAVE_LIBUDEV
	udev_unref(media_enum->udev);
#endif

	free(media_enum->devices);
	free(media_enum->syspaths);
	free(media_enum);
}

int media_enumerate_scan(struct media_enumerate *media_enum)
{
	media_enumerate_scan_media(media_enum);
	media_enumerate_scan_video(media_enum);
	media_enumerate_scan_audio(media_enum);

	return 0;
}

struct media_device **media_enumerate_get_devices(struct media_enumerate *media_enum)
{
	return media_enum->devices;
}

unsigned int media_enumerate_get_devices_count(struct media_enumerate *media_enum)
{
	return media_enum->devices_count;
}