/*
 * Copyright (C) 2017  Red Hat, Inc.
 *
 * 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, see <http://www.gnu.org/licenses/>.
 *
 * Author: Vratislav Podzimek <vpodzime@redhat.com>
 */

#include <blockdev/utils.h>
#include <blockdev/part_err.h>
#include <check_deps.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include "vfat.h"
#include "fs.h"
#include "common.h"

static volatile guint avail_deps = 0;
static GMutex deps_check_lock;

#define DEPS_MKFSVFAT 0
#define DEPS_MKFSVFAT_MASK (1 << DEPS_MKFSVFAT)
#define DEPS_FATLABEL 1
#define DEPS_FATLABEL_MASK (1 << DEPS_FATLABEL)
#define DEPS_FSCKVFAT 2
#define DEPS_FSCKVFAT_MASK (1 << DEPS_FSCKVFAT)

#define DEPS_LAST 3

static const UtilDep deps[DEPS_LAST] = {
    {"mkfs.vfat", NULL, NULL, NULL},
    {"fatlabel", NULL, NULL, NULL},
    {"fsck.vfat", NULL, NULL, NULL},
};

static guint32 fs_mode_util[BD_FS_MODE_LAST+1] = {
    /*   mkfs          wipe     check               repair                set-label            query          resize */
    DEPS_MKFSVFAT_MASK, 0, DEPS_FSCKVFAT_MASK, DEPS_FSCKVFAT_MASK,   DEPS_FATLABEL_MASK,  DEPS_FSCKVFAT_MASK,  0
};

#define UNUSED __attribute__((unused))

#ifdef __clang__
#define ZERO_INIT {}
#else
#define ZERO_INIT {0}
#endif

/**
 * bd_fs_vfat_is_tech_avail:
 * @tech: the queried tech
 * @mode: a bit mask of queried modes of operation (#BDFSTechMode) for @tech
 * @error: (out): place to store error (details about why the @tech-@mode combination is not available)
 *
 * Returns: whether the @tech-@mode combination is available -- supported by the
 *          plugin implementation and having all the runtime dependencies available
 */
gboolean __attribute__ ((visibility ("hidden")))
bd_fs_vfat_is_tech_avail (BDFSTech tech UNUSED, guint64 mode, GError **error) {
    guint32 required = 0;
    guint i = 0;
    for (i = 0; i <= BD_FS_MODE_LAST; i++)
        if (mode & (1 << i))
            required |= fs_mode_util[i];

    return check_deps (&avail_deps, required, deps, DEPS_LAST, &deps_check_lock, error);
}

/**
 * bd_fs_vfat_info_copy: (skip)
 *
 * Creates a new copy of @data.
 */
BDFSVfatInfo* bd_fs_vfat_info_copy (BDFSVfatInfo *data) {
    if (data == NULL)
        return NULL;

    BDFSVfatInfo *ret = g_new0 (BDFSVfatInfo, 1);

    ret->label = g_strdup (data->label);
    ret->uuid = g_strdup (data->uuid);
    ret->cluster_size = data->cluster_size;
    ret->cluster_count = data->cluster_count;
    ret->free_cluster_count = data->free_cluster_count;

    return ret;
}

/**
 * bd_fs_vfat_info_free: (skip)
 *
 * Frees @data.
 */
void bd_fs_vfat_info_free (BDFSVfatInfo *data) {
    if (data == NULL)
        return;

    g_free (data->label);
    g_free (data->uuid);
    g_free (data);
}

/**
 * set_parted_error: (skip)
 *
 * Set error from the parted error stored in 'error_msg'. In case there is none,
 * the error is set up with an empty string. Otherwise it is set up with the
 * parted's error message and is a subject to later g_prefix_error() call.
 *
 * Returns: whether there was some message from parted or not
 */
static gboolean set_parted_error (GError **error, BDFsError type) {
    gchar *error_msg = NULL;
    error_msg = bd_get_error_msg ();
    if (error_msg) {
        g_set_error (error, BD_FS_ERROR, type,
                     " (%s)", error_msg);
        g_free (error_msg);
        error_msg = NULL;
        return TRUE;
    } else {
        g_set_error_literal (error, BD_FS_ERROR, type, "");
        return FALSE;
    }
}

/**
 * bd_fs_vfat_mkfs:
 * @device: the device to create a new vfat fs on
 * @extra: (allow-none) (array zero-terminated=1): extra options for the creation (right now
 *                                                 passed to the 'mkfs.vfat' utility)
 * @error: (out): place to store error (if any)
 *
 * Returns: whether a new vfat fs was successfully created on @device or not
 *
 * Tech category: %BD_FS_TECH_VFAT-%BD_FS_TECH_MODE_MKFS
 */
gboolean bd_fs_vfat_mkfs (const gchar *device, const BDExtraArg **extra, GError **error) {
    const gchar *args[4] = {"mkfs.vfat", "-I", device, NULL};

    if (!check_deps (&avail_deps, DEPS_MKFSVFAT_MASK, deps, DEPS_LAST, &deps_check_lock, error))
        return FALSE;

    return bd_utils_exec_and_report_error (args, extra, error);
}

/**
 * bd_fs_vfat_wipe:
 * @device: the device to wipe an vfat signature from
 * @error: (out): place to store error (if any)
 *
 * Returns: whether an vfat signature was successfully wiped from the @device or
 *          not
 *
 * Tech category: %BD_FS_TECH_VFAT-%BD_FS_TECH_MODE_WIPE
 */
gboolean bd_fs_vfat_wipe (const gchar *device, GError **error) {
    return wipe_fs (device, "vfat", TRUE, error);
}

/**
 * bd_fs_vfat_check:
 * @device: the device containing the file system to check
 * @extra: (allow-none) (array zero-terminated=1): extra options for the repair (right now
 *                                                 passed to the 'fsck.vfat' utility)
 * @error: (out): place to store error (if any)
 *
 * Returns: whether an vfat file system on the @device is clean or not
 *
 * Tech category: %BD_FS_TECH_VFAT-%BD_FS_TECH_MODE_CHECK
 */
gboolean bd_fs_vfat_check (const gchar *device, const BDExtraArg **extra, GError **error) {
    const gchar *args[4] = {"fsck.vfat", "-n", device, NULL};
    gint status = 0;
    gboolean ret = FALSE;

    if (!check_deps (&avail_deps, DEPS_FSCKVFAT_MASK, deps, DEPS_LAST, &deps_check_lock, error))
        return FALSE;

    ret = bd_utils_exec_and_report_status_error (args, extra, &status, error);
    if (!ret && (status == 1)) {
        /* no error should be reported for exit code 1 -- Recoverable errors have been detected */
        g_clear_error (error);
    }
    return ret;
}

/**
 * bd_fs_vfat_repair:
 * @device: the device containing the file system to repair
 * @extra: (allow-none) (array zero-terminated=1): extra options for the repair (right now
 *                                                 passed to the 'fsck.vfat' utility)
 * @error: (out): place to store error (if any)
 *
 * Returns: whether an vfat file system on the @device was successfully repaired
 *          (if needed) or not (error is set in that case)
 *
 * Tech category: %BD_FS_TECH_VFAT-%BD_FS_TECH_MODE_REPAIR
 */
gboolean bd_fs_vfat_repair (const gchar *device, const BDExtraArg **extra, GError **error) {
    const gchar *args[4] = {"fsck.vfat", "-a", device, NULL};

    if (!check_deps (&avail_deps, DEPS_FSCKVFAT_MASK, deps, DEPS_LAST, &deps_check_lock, error))
        return FALSE;

    return bd_utils_exec_and_report_error (args, extra, error);
}

/**
 * bd_fs_vfat_set_label:
 * @device: the device containing the file system to set label for
 * @label: label to set
 * @error: (out): place to store error (if any)
 *
 * Returns: whether the label of vfat file system on the @device was
 *          successfully set or not
 *
 * Tech category: %BD_FS_TECH_VFAT-%BD_FS_TECH_MODE_SET_LABEL
 */
gboolean bd_fs_vfat_set_label (const gchar *device, const gchar *label, GError **error) {
    const gchar *args[4] = {"fatlabel", device, label, NULL};

    if (!check_deps (&avail_deps, DEPS_FATLABEL_MASK, deps, DEPS_LAST, &deps_check_lock, error))
        return FALSE;

    return bd_utils_exec_and_report_error (args, NULL, error);
}

/**
 * bd_fs_vfat_get_info:
 * @device: the device containing the file system to get info for
 * @error: (out): place to store error (if any)
 *
 * Returns: (transfer full): information about the file system on @device or
 *                           %NULL in case of error
 *
 * Tech category: %BD_FS_TECH_VFAT-%BD_FS_TECH_MODE_QUERY
 */
BDFSVfatInfo* bd_fs_vfat_get_info (const gchar *device, GError **error) {
    const gchar *args[4] = {"fsck.vfat", "-nv", device, NULL};
    gboolean success = FALSE;
    BDFSVfatInfo *ret = NULL;
    gchar *output = NULL;
    gchar **lines = NULL;
    gchar **line_p = NULL;
    gboolean have_cluster_size = FALSE;
    gboolean have_cluster_count = FALSE;
    guint64 full_cluster_count = 0;
    guint64 cluster_count = 0;
    gchar **key_val = NULL;
    gint scanned = 0;

    if (!check_deps (&avail_deps, DEPS_FSCKVFAT_MASK, deps, DEPS_LAST, &deps_check_lock, error))
        return NULL;

    ret = g_new0 (BDFSVfatInfo, 1);

    success = get_uuid_label (device, &(ret->uuid), &(ret->label), error);
    if (!success) {
        /* error is already populated */
        bd_fs_vfat_info_free (ret);
        return NULL;
    }

    success = bd_utils_exec_and_capture_output (args, NULL, &output, error);
    if (!success) {
        /* error is already populated */
        bd_fs_vfat_info_free (ret);
        return NULL;
    }

    lines = g_strsplit (output, "\n", 0);
    g_free (output);
    for (line_p=lines; *line_p && (!have_cluster_size || !have_cluster_count); line_p++) {
        if (!have_cluster_size && g_str_has_suffix (*line_p, "bytes per cluster")) {
            ret->cluster_size = g_ascii_strtoull (*line_p, NULL, 0);
            have_cluster_size = TRUE;
        } else if (!have_cluster_count && g_str_has_prefix (*line_p, device)) {
            key_val = g_strsplit (*line_p, ",", 2);
            scanned = sscanf (key_val[1], " %" G_GUINT64_FORMAT "/" "%" G_GUINT64_FORMAT " clusters",
                              &full_cluster_count, &cluster_count);
            if (scanned != 2) {
                g_set_error (error, BD_FS_ERROR, BD_FS_ERROR_FAIL,
                             "Failed to get number of FAT clusters for '%s'", device);
                bd_fs_vfat_info_free (ret);
                g_strfreev (key_val);
                g_strfreev (lines);
                return NULL;
            }
            ret->cluster_count = cluster_count;
            ret->free_cluster_count = cluster_count - full_cluster_count;
            have_cluster_count = TRUE;
            g_strfreev (key_val);
        }
    }
    g_strfreev (lines);

    return ret;
}

/**
 * bd_fs_vfat_resize:
 * @device: the device the file system of which to resize
 * @new_size: new requested size for the file system (if 0, the file system is
 *            adapted to the underlying block device)
 * @error: (out): place to store error (if any)
 *
 * Returns: whether the file system on @device was successfully resized or not
 *
 * Tech category: %BD_FS_TECH_VFAT-%BD_FS_TECH_MODE_RESIZE
 */
gboolean bd_fs_vfat_resize (const gchar *device, guint64 new_size, GError **error) {
    PedDevice *ped_dev = NULL;
    PedGeometry geom = ZERO_INIT;
    PedGeometry new_geom = ZERO_INIT;
    PedFileSystem *fs = NULL;
    PedSector start = 0;
    PedSector length = 0;
    gint status = 0;
    guint64 progress_id = 0;
    gchar *msg = NULL;

    msg = g_strdup_printf ("Started resizing vfat filesystem on the device '%s'", device);
    progress_id = bd_utils_report_started (msg);
    g_free (msg);

    ped_dev = ped_device_get (device);
    if (!ped_dev) {
        g_set_error (error, BD_FS_ERROR, BD_FS_ERROR_FAIL,
                     "Failed to get ped device for the device '%s'", device);
        bd_utils_report_finished (progress_id, (*error)->message);
        return FALSE;
    }

    status = ped_device_open (ped_dev);
    if (status == 0) {
        g_set_error (error, BD_FS_ERROR, BD_FS_ERROR_FAIL,
                     "Failed to get open the device '%s'", device);
        bd_utils_report_finished (progress_id, (*error)->message);
        return FALSE;
    }

    status = ped_geometry_init (&geom, ped_dev, start, ped_dev->length);
    if (status == 0) {
        g_set_error (error, BD_FS_ERROR, BD_FS_ERROR_FAIL,
                     "Failed to initialize geometry for the device '%s'", device);
        ped_device_close (ped_dev);
        bd_utils_report_finished (progress_id, (*error)->message);
        return FALSE;
    }

    fs = ped_file_system_open(&geom);
    if (!fs) {
        g_set_error (error, BD_FS_ERROR, BD_FS_ERROR_FAIL,
                     "Failed to read the filesystem on the device '%s'", device);
        ped_device_close (ped_dev);
        bd_utils_report_finished (progress_id, (*error)->message);
        return FALSE;
    }

    if (new_size == 0)
        length = ped_dev->length;
    else
        length = (PedSector) ((PedSector) new_size / ped_dev->sector_size);

    status = ped_geometry_init(&new_geom, ped_dev, start, length);
    if (status == 0) {
        g_set_error (error, BD_FS_ERROR, BD_FS_ERROR_FAIL,
                     "Failed to initialize new geometry for the filesystem on '%s'", device);
        ped_file_system_close (fs);
        ped_device_close (ped_dev);
        bd_utils_report_finished (progress_id, (*error)->message);
        return FALSE;
    }

    status = ped_file_system_resize(fs, &new_geom, NULL);
    if (status == 0) {
        set_parted_error (error, BD_FS_ERROR_FAIL);
        g_prefix_error (error, "Failed to resize the filesystem on '%s'", device);
        ped_file_system_close (fs);
        ped_device_close (ped_dev);
        bd_utils_report_finished (progress_id, (*error)->message);
        return FALSE;
    }

    ped_file_system_close (fs);
    ped_device_close (ped_dev);
    bd_utils_report_finished (progress_id, "Completed");

    return TRUE;

}