/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*!
 * \file      exynos_mc.c
 * \brief     source file for libexynosv4l2
 * \author    Jinsung Yang (jsgood.yang@samsung.com)
 * \author    Sangwoo Park (sw5771.park@samsung.com)
 * \date      2012/01/17
 *
 * <b>Revision History: </b>
 * - 2012/01/17: Jinsung Yang (jsgood.yang@samsung.com) \n
 *   Initial version
 *
 */

#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <fcntl.h>
#include <errno.h>
#include <ctype.h>
#include <string.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <media.h>
#include <linux/kdev_t.h>
#include <linux/types.h>
#include <unistd.h>

#include "exynos_v4l2.h"

//#define LOG_NDEBUG 0
#define LOG_TAG "libexynosv4l2-mc"
#include <log/log.h>

static inline unsigned int __media_entity_type(struct media_entity *entity)
{
    return entity->info.type & MEDIA_ENT_TYPE_MASK;
}

static void __media_debug_default(void *ptr, ...)
{
    va_list argptr;
    va_start(argptr, ptr);
    vprintf((const char*)ptr, argptr);
    va_end(argptr);
}

static void __media_debug_set_handler(
                struct media_device *media,
                void (*debug_handler)(void *, ...),
                void *debug_priv)
{
    if (debug_handler) {
        media->debug_handler = debug_handler;
        media->debug_priv = debug_priv;
    } else {
        media->debug_handler = __media_debug_default;
        media->debug_priv = NULL;
    }
}

static struct media_link *__media_entity_add_link(struct media_entity *entity)
{
    return NULL;
}


static int __media_enum_links(struct media_device *media)
{
    return 0;
}

static int __media_get_devname_sysfs(struct media_entity *entity)
{
    //struct stat devstat;
    char devname[32];
    char sysname[32];
    char target[1024];
    char *p;
    int ret;

    snprintf(sysname, sizeof(sysname), "/sys/dev/char/%u:%u", entity->info.v4l.major,
        entity->info.v4l.minor);

    ret = readlink(sysname, target, sizeof(target));
    if (ret < 0 || ret >= (int)sizeof(target))
        return -errno;

    target[ret] = '\0';
    p = strrchr(target, '/');
    if (p == NULL)
        return -EINVAL;

    snprintf(devname, sizeof(devname), "/tmp/%s", p + 1);

    ret = mknod(devname, 0666 | S_IFCHR, MKDEV(81, entity->info.v4l.minor));
    strncpy(entity->devname, devname, sizeof(devname) - 1);

    return 0;
}

static int __media_get_media_fd(const char *filename, struct media_device *media)
{
    ssize_t num;
    int media_node;
    char *ptr;

    ALOGD("%s: %s", __func__, filename);

    media->fd = open(filename, O_RDWR, 0);
    if (media->fd < 0) {
        ALOGE("Open sysfs media device failed, media->fd: %d", media->fd);
        return -1;
    }

    ALOGD("%s: media->fd: %d", __func__, media->fd);

    return media->fd;

}

static int __media_enum_entities(struct media_device *media)
{
    return 0;
}

static struct media_device *__media_open_debug(
        const char *filename,
        void (*debug_handler)(void *, ...),
        void *debug_priv)
{
    struct media_device *media;
    int ret;

    media = (struct media_device *)calloc(1, sizeof(struct media_device));
    if (media == NULL) {
        ALOGE("media: %p", media);
        return NULL;
    }

    __media_debug_set_handler(media, debug_handler, debug_priv);

    ALOGD("%s: Opening media device %s", __func__, filename);
    ALOGD("%s: media: %p", __func__, media);

    media->fd = __media_get_media_fd(filename, media);
    if (media->fd < 0) {
        exynos_media_close(media);
        ALOGE("failed __media_get_media_fd %s", filename);
        return NULL;
    }

    ALOGD("%s: media->fd: %d", __func__, media->fd);
    ret = __media_enum_entities(media);

    if (ret < 0) {
        ALOGE("Unable to enumerate entities for device %s (%s)", filename, strerror(-ret));
        exynos_media_close(media);
        return NULL;
    }

    ALOGD("%s: Found %u entities", __func__, media->entities_count);
    ALOGD("%s: Enumerating pads and links", __func__);

    ret = __media_enum_links(media);
    if (ret < 0) {
        ALOGE("Unable to enumerate pads and links for device %s", filename);
        exynos_media_close(media);
        return NULL;
    }

    return media;
}

/**
 * @brief Open a media device.
 * @param filename - name (including path) of the device node.
 *
 * Open the media device referenced by @a filename and enumerate entities, pads and
 * links.
 *
 * @return A pointer to a newly allocated media_device structure instance on
 * success and NULL on failure. The returned pointer must be freed with
 * exynos_media_close when the device isn't needed anymore.
 */
struct media_device *exynos_media_open(const char *filename)
{
    return __media_open_debug(filename, (void (*)(void *, ...))fprintf, stdout);
}

/**
 * @brief Close a media device.
 * @param media - device instance.
 *
 * Close the @a media device instance and free allocated resources. Access to the
 * device instance is forbidden after this function returns.
 */
void exynos_media_close(struct media_device *media)
{
    unsigned int i;

    if (media->fd != -1)
        close(media->fd);

    for (i = 0; i < media->entities_count; ++i) {
        struct media_entity *entity = &media->entities[i];

        free(entity->pads);
        free(entity->links);
        if (entity->fd != -1)
            close(entity->fd);
    }

    free(media->entities);
    free(media);
}

/**
 * @brief Locate the pad at the other end of a link.
 * @param pad - sink pad at one end of the link.
 *
 * Locate the source pad connected to @a pad through an enabled link. As only one
 * link connected to a sink pad can be enabled at a time, the connected source
 * pad is guaranteed to be unique.
 *
 * @return A pointer to the connected source pad, or NULL if all links connected
 * to @a pad are disabled. Return NULL also if @a pad is not a sink pad.
 */
struct media_pad *exynos_media_entity_remote_source(struct media_pad *pad)
{
    return NULL;
}

/**
 * @brief Find an entity by its name.
 * @param media - media device.
 * @param name - entity name.
 * @param length - size of @a name.
 *
 * Search for an entity with a name equal to @a name.
 *
 * @return A pointer to the entity if found, or NULL otherwise.
 */
struct media_entity *exynos_media_get_entity_by_name(struct media_device *media,
                          const char *name, size_t length)
{
    unsigned int i;
    struct media_entity *entity;

    for (i = 0; i < media->entities_count; ++i) {
        entity = &media->entities[i];

        if (strncmp(entity->info.name, name, length) == 0)
            return entity;
    }

    return NULL;
}

/**
 * @brief Find an entity by its ID.
 * @param media - media device.
 * @param id - entity ID.
 *
 * Search for an entity with an ID equal to @a id.
 *
 * @return A pointer to the entity if found, or NULL otherwise.
 */
struct media_entity *exynos_media_get_entity_by_id(struct media_device *media,
                        __u32 id)
{
    unsigned int i;

    for (i = 0; i < media->entities_count; ++i) {
        struct media_entity *entity = &media->entities[i];

        if (entity->info.id == id)
            return entity;
    }

    return NULL;
}

/**
 * @brief Configure a link.
 * @param media - media device.
 * @param source - source pad at the link origin.
 * @param sink - sink pad at the link target.
 * @param flags - configuration flags.
 *
 * Locate the link between @a source and @a sink, and configure it by applying
 * the new @a flags.
 *
 * Only the MEDIA_LINK_FLAG_ENABLED flag is writable.
 *
 * @return 0 on success, -1 on failure:
 *       -ENOENT: link not found
 *       - other error codes returned by MEDIA_IOC_SETUP_LINK
 */
int exynos_media_setup_link(struct media_device *media,
             struct media_pad *source,
             struct media_pad *sink,
             __u32 flags)
{
    return 0;
}

/**
 * @brief Reset all links to the disabled state.
 * @param media - media device.
 *
 * Disable all links in the media device. This function is usually used after
 * opening a media device to reset all links to a known state.
 *
 * @return 0 on success, or a negative error code on failure.
 */
int exynos_media_reset_links(struct media_device *media)
{
    return 0;
}

#ifdef HAVE_LIBUDEV

#include <libudev.h>

static inline int __media_udev_open(struct udev **udev)
{
    *udev = udev_new();
    if (*udev == NULL)
        return -ENOMEM;
    return 0;
}

static inline void __media_udev_close(struct udev *udev)
{
    if (udev != NULL)
        udev_unref(udev);
}

static int __media_get_devname_udev(struct udev *udev,
        struct media_entity *entity)
{
    struct udev_device *device;
    dev_t devnum;
    const char *p;
    int ret = -ENODEV;

    if (udev == NULL)
        return -EINVAL;

    devnum = makedev(entity->info.v4l.major, entity->info.v4l.minor);
    ALOGE("looking up device: %u:%u",
          major(devnum), minor(devnum));
    device = udev_device_new_from_devnum(udev, 'c', devnum);
    if (device) {
        p = udev_device_get_devnode(device);
        if (p) {
            strncpy(entity->devname, p, sizeof(entity->devname));
            entity->devname[sizeof(entity->devname) - 1] = '\0';
        }
        ret = 0;
    }

    udev_device_unref(device);

    return ret;
}

#else    /* HAVE_LIBUDEV */

struct udev;

static inline int __media_udev_open(struct udev **udev) { return 0; }

static inline void __media_udev_close(struct udev *udev) { }

static inline int __media_get_devname_udev(struct udev *udev,
        struct media_entity *entity)
{
    return -ENOTSUP;
}

#endif    /* HAVE_LIBUDEV */

/**
 * @brief Parse string to a pad on the media device.
 * @param media - media device.
 * @param p - input string
 * @param endp - pointer to string where parsing ended
 *
 * Parse NULL terminated string describing a pad and return its struct
 * media_pad instance.
 *
 * @return Pointer to struct media_pad on success, NULL on failure.
 */
struct media_pad *exynos_media_parse_pad(struct media_device *media,
                  const char *p, char **endp)
{
    return NULL;
}

/**
 * @brief Parse string to a link on the media device.
 * @param media - media device.
 * @param p - input string
 * @param endp - pointer to p where parsing ended
 *
 * Parse NULL terminated string p describing a link and return its struct
 * media_link instance.
 *
 * @return Pointer to struct media_link on success, NULL on failure.
 */
struct media_link *exynos_media_parse_link(
        struct media_device *media,
        const char *p,
        char **endp)
{
    struct media_link *link;
    struct media_pad *source;
    struct media_pad *sink;
    unsigned int i;
    char *end;

    source = exynos_media_parse_pad(media, p, &end);
    if (source == NULL)
        return NULL;

    if (end[0] != '-' || end[1] != '>')
        return NULL;
    p = end + 2;

    sink = exynos_media_parse_pad(media, p, &end);
    if (sink == NULL)
        return NULL;

    *endp = end;

    for (i = 0; i < source->entity->num_links; i++) {
        link = &source->entity->links[i];

        if (link->source == source && link->sink == sink)
            return link;
    }

    return NULL;
}

/**
 * @brief Parse string to a link on the media device and set it up.
 * @param media - media device.
 * @param p - input string
 *
 * Parse NULL terminated string p describing a link and its configuration
 * and configure the link.
 *
 * @return 0 on success, or a negative error code on failure.
 */
int exynos_media_parse_setup_link(
        struct media_device *media,
        const char *p,
        char **endp)
{
    return 0;
}

/**
 * @brief Parse string to link(s) on the media device and set it up.
 * @param media - media device.
 * @param p - input string
 *
 * Parse NULL terminated string p describing link(s) separated by
 * commas (,) and configure the link(s).
 *
 * @return 0 on success, or a negative error code on failure.
 */
int exynos_media_parse_setup_links(struct media_device *media, const char *p)
{
    return 0;
}