/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */

#include <assert.h>
#include <string.h>
#include <nffs/nffs.h>
#include <nffs/os.h>

static struct nffs_dir *
nffs_dir_alloc(void)
{
    struct nffs_dir *dir;

    dir = nffs_os_mempool_get(&nffs_dir_pool);
    if (dir != NULL) {
        memset(dir, 0, sizeof *dir);
    }

    return dir;
}

static int
nffs_dir_free(struct nffs_dir *dir)
{
    int rc;

    if (dir != NULL) {
        rc = nffs_os_mempool_free(&nffs_dir_pool, dir);
        if (rc != 0) {
            return FS_EOS;
        }
    }

    return 0;
}

int
nffs_dir_open(const char *path, struct nffs_dir **out_dir)
{
    struct nffs_inode_entry *parent_inode_entry;
    struct nffs_dir *dir;
    int rc;

    rc = nffs_path_find_inode_entry(path, &parent_inode_entry);
    if (rc != 0) {
        return rc;
    }

    if (!nffs_hash_id_is_dir(parent_inode_entry->nie_hash_entry.nhe_id)) {
        return FS_EINVAL;
    }

    dir = nffs_dir_alloc();
    if (dir == NULL) {
        return FS_ENOMEM;
    }

    dir->nd_parent_inode_entry = parent_inode_entry;
    nffs_inode_inc_refcnt(dir->nd_parent_inode_entry);
    memset(&dir->nd_dirent, 0, sizeof dir->nd_dirent);

    *out_dir = dir;

    return 0;
}

int
nffs_dir_read(struct nffs_dir *dir, struct nffs_dirent **out_dirent)
{
    struct nffs_inode_entry *child;
    int rc;

    if (dir->nd_dirent.nde_inode_entry == NULL) {
        child = SLIST_FIRST(&dir->nd_parent_inode_entry->nie_child_list);
    } else {
        child = SLIST_NEXT(dir->nd_dirent.nde_inode_entry, nie_sibling_next);
        rc = nffs_inode_dec_refcnt(dir->nd_dirent.nde_inode_entry);
        if (rc != 0) {
            /* XXX: Need to clean up anything? */
            return rc;
        }
    }
    dir->nd_dirent.nde_inode_entry = child;

    if (child == NULL) {
        *out_dirent = NULL;
        return FS_ENOENT;
    }

    nffs_inode_inc_refcnt(child);
    *out_dirent = &dir->nd_dirent;

    return 0;
}

int
nffs_dir_close(struct nffs_dir *dir)
{
    int rc;

    if (dir == NULL) {
        return 0;
    }

    if (dir->nd_dirent.nde_inode_entry != NULL) {
        rc = nffs_inode_dec_refcnt(dir->nd_dirent.nde_inode_entry);
        if (rc != 0) {
            return rc;
        }
    }

    rc = nffs_inode_dec_refcnt(dir->nd_parent_inode_entry);
    if (rc != 0) {
        return rc;
    }

    rc = nffs_dir_free(dir);
    if (rc != 0) {
        return rc;
    }

    return 0;
}