/*
 * Copyright 2020 Suhel Mehta, mehtasuhel@gmail.com
 * All rights reserved. Distributed under the terms of the MIT License.
 */

#include <string.h>

#ifdef FS_SHELL
#include "fssh_api_wrapper.h"
#endif
#include <file_systems/fs_ops_support.h>

#include "DirectoryIterator.h"
#include "Inode.h"
#include "system_dependencies.h"
#include "ufs2.h"
#include "Volume.h"

#define TRACE_UFS2
#ifdef TRACE_UFS2
#define TRACE(x...) dprintf("\33[34mufs2:\33[0m " x)
#else
#define TRACE(x...) ;
#endif
#define ERROR(x...) dprintf("\33[34mufs2:\33[0m " x)


struct identify_cookie
{
        ufs2_super_block super_block;
        int cookie;
};


//      #pragma mark - Scanning
static float
ufs2_identify_partition(int fd, partition_data *partition, void **_cookie)
{
        ufs2_super_block superBlock;
        status_t status = Volume::Identify(fd, &superBlock);
        if (status != B_OK)
                return -1;

        identify_cookie* cookie = new identify_cookie;
        memcpy(&cookie->super_block, &superBlock, sizeof(ufs2_super_block));
        *_cookie = cookie;

        return 0.8f;
}


static status_t
ufs2_scan_partition(int fd, partition_data *partition, void *_cookie)
{
        identify_cookie* cookie = (identify_cookie*)_cookie;

        partition->status = B_PARTITION_VALID;
        partition->flags |= B_PARTITION_FILE_SYSTEM | B_PARTITION_READ_ONLY;
        partition->block_size = cookie->super_block.fs_bsize;
        partition->content_size = cookie->super_block.fs_fsize
                * cookie->super_block.fs_size;
        partition->content_name = strdup(cookie->super_block.fs_volname);
        if (partition->content_name == NULL)
                return B_NO_MEMORY;

        return B_OK;
}


static void
ufs2_free_identify_partition_cookie(partition_data *partition, void *_cookie)
{
        identify_cookie* cookie = (identify_cookie*)_cookie;
        delete cookie;
        return;
}


//      #pragma mark -
static status_t
ufs2_mount(fs_volume *_volume, const char *device, uint32 flags,
                  const char *args, ino_t *_rootID)
{
        TRACE("Tracing mount()\n");
        Volume* volume = new(std::nothrow) Volume(_volume);
        if (volume == NULL)
                return B_NO_MEMORY;

        _volume->private_volume = volume;
        _volume->ops = &gUfs2VolumeOps;
        *_rootID = UFS2_ROOT;
        status_t status = volume->Mount(device, flags);
        if (status != B_OK){
                ERROR("Failed mounting the volume. Error: %s\n", strerror(status));
                delete volume;
                return status;
        }
        return B_OK;
}


static status_t
ufs2_unmount(fs_volume *_volume)
{
        Volume* volume = (Volume *)_volume->private_volume;

        status_t status = volume->Unmount();
        delete volume;

        return status;
}


static status_t
ufs2_read_fs_info(fs_volume *_volume, struct fs_info *info)
{
        Volume* volume = (Volume*)_volume->private_volume;

        // File system flags
        info->flags = B_FS_IS_PERSISTENT
                | (volume->IsReadOnly() ? B_FS_IS_READONLY : 0);
        info->io_size = 65536;
        info->block_size = volume->SuperBlock().fs_fsize;
        info->total_blocks = volume->SuperBlock().fs_size;
        info->free_blocks = volume->SuperBlock().fs_cstotal.cs_nbfree;

        strlcpy(info->volume_name, volume->Name(), sizeof(info->volume_name));
        strlcpy(info->fsh_name, "UFS2", sizeof(info->fsh_name));

        return B_OK;
}


//      #pragma mark -

static status_t
ufs2_get_vnode(fs_volume *_volume, ino_t id, fs_vnode *_node, int *_type,
                          uint32 *_flags, bool reenter)
{
        Volume* volume = (Volume*)_volume->private_volume;

        Inode* inode = new(std::nothrow) Inode(volume, id);
        if (inode == NULL)
                return B_NO_MEMORY;

        status_t status = inode->InitCheck();
        if (status != B_OK) {
                delete inode;
                ERROR("get_vnode: InitCheck() failed. Error: %s\n", strerror(status));
                return status;
        }
        _node->private_node = inode;
        _node->ops = &gufs2VnodeOps;
        *_type = inode->Mode();
        *_flags = 0;

        return B_OK;

}


static status_t
ufs2_put_vnode(fs_volume *_volume, fs_vnode *_node, bool reenter)
{
        return B_NOT_SUPPORTED;
}


static bool
ufs2_can_page(fs_volume *_volume, fs_vnode *_node, void *_cookie)
{
        return false;
}


static status_t
ufs2_read_pages(fs_volume *_volume, fs_vnode *_node, void *_cookie,
                           off_t pos, const iovec *vecs, size_t count, size_t *_numBytes)
{
        return B_NOT_SUPPORTED;
}


static status_t
ufs2_io(fs_volume *_volume, fs_vnode *_node, void *_cookie,
           io_request *request)
{
        return B_NOT_SUPPORTED;
}


static status_t
ufs2_get_file_map(fs_volume *_volume, fs_vnode *_node, off_t offset,
                                 size_t size, struct file_io_vec *vecs, size_t *_count)
{
        return B_NOT_SUPPORTED;
}


//      #pragma mark -

static status_t
ufs2_lookup(fs_volume *_volume, fs_vnode *_directory, const char *name,
                   ino_t *_vnodeID)
{
        Volume* volume = (Volume*)_volume->private_volume;
        Inode* directory = (Inode*)_directory->private_node;

        // check access permissions
        status_t status = directory->CheckPermissions(X_OK);
        if (status < B_OK)
                return status;

        status = DirectoryIterator(directory).Lookup(name, _vnodeID);
        if (status != B_OK)
                return status;

        status = get_vnode(volume->FSVolume(), *_vnodeID, NULL);
        return status;
}


static status_t
ufs2_ioctl(fs_volume *_volume, fs_vnode *_node, void *_cookie, uint32 cmd,
                  void *buffer, size_t bufferLength)
{
        return B_NOT_SUPPORTED;
}


static status_t
ufs2_read_stat(fs_volume *_volume, fs_vnode *_node, struct stat *stat)
{
        Inode* inode = (Inode*)_node->private_node;
        stat->st_dev = inode->GetVolume()->ID();
        stat->st_ino = inode->ID();
        stat->st_nlink = inode->LinkCount();
        stat->st_blksize = 65536;

        stat->st_uid = inode->UserID();
        stat->st_gid = inode->GroupID();
        stat->st_mode = inode->Mode();
        stat->st_type = 0;

        inode->GetAccessTime(stat->st_atim);
        inode->GetModificationTime(stat->st_mtim);
        inode->GetChangeTime(stat->st_ctim);
        inode->GetCreationTime(stat->st_crtim);

        stat->st_size = inode->Size();
        stat->st_blocks = inode->NumBlocks();

        return B_OK;
}


static status_t
ufs2_open(fs_volume * _volume, fs_vnode *_node, int openMode,
                 void **_cookie)
{
        //Volume* volume = (Volume*)_volume->private_volume;
        Inode* inode = (Inode*)_node->private_node;

        // opening a directory read-only is allowed, although you can't read
        // any data from it.
        if (inode->IsDirectory() && (openMode & O_RWMASK) != O_RDONLY)
                return B_IS_A_DIRECTORY;

        status_t status =  inode->CheckPermissions(open_mode_to_access(openMode)
                | (openMode & O_TRUNC ? W_OK : 0));
        if (status != B_OK)
                return status;

        file_cookie* cookie = new(std::nothrow) file_cookie;
        if (cookie == NULL)
                return B_NO_MEMORY;
        ObjectDeleter<file_cookie> cookieDeleter(cookie);

        cookie->last_size = inode->Size();
        cookie->last_notification = system_time();

//      fileCacheEnabler.Detach();
        cookieDeleter.Detach();
        *_cookie = cookie;
        return B_OK;
}


static status_t
ufs2_read(fs_volume *_volume, fs_vnode *_node, void *_cookie, off_t pos,
                 void *buffer, size_t *_length)
{
        Inode* inode = (Inode*)_node->private_node;

        if (!inode->IsFile()) {
                *_length = 0;
                return inode->IsDirectory() ? B_IS_A_DIRECTORY : B_BAD_VALUE;
        }

        return inode->ReadAt(pos, (uint8*)buffer, _length);
}


static status_t
ufs2_close(fs_volume *_volume, fs_vnode *_node, void *_cookie)
{
        return B_OK;
}


static status_t
ufs2_free_cookie(fs_volume *_volume, fs_vnode *_node, void *_cookie)
{
        file_cookie* cookie = (file_cookie*)_cookie;

        delete cookie;
        return B_OK;
}

static status_t
ufs2_access(fs_volume *_volume, fs_vnode *_node, int accessMode)
{
        Inode* inode = (Inode*)_node->private_node;
        return inode->CheckPermissions(accessMode);
}


static status_t
ufs2_read_link(fs_volume *_volume, fs_vnode *_node, char *buffer,
                          size_t *_bufferSize)
{
        Inode* inode = (Inode*)_node->private_node;

        return inode->ReadLink(buffer, _bufferSize);
}


status_t
ufs2_unlink(fs_volume *_volume, fs_vnode *_directory, const char *name)
{
        return B_NOT_SUPPORTED;
}


//      #pragma mark - Directory functions

static status_t
ufs2_create_dir(fs_volume *_volume, fs_vnode *_directory, const char *name,
                           int mode)
{
        return B_NOT_SUPPORTED;
}


static status_t
ufs2_remove_dir(fs_volume *_volume, fs_vnode *_directory, const char *name)
{
        return B_NOT_SUPPORTED;
}


static status_t
ufs2_open_dir(fs_volume * /*_volume*/, fs_vnode *_node, void **_cookie)
{
        Inode* inode = (Inode*)_node->private_node;

        status_t status = inode->CheckPermissions(R_OK);
        if (status < B_OK)
                return status;

        if (!inode->IsDirectory())
                return B_NOT_A_DIRECTORY;

        DirectoryIterator* iterator = new(std::nothrow) DirectoryIterator(inode);
        if (iterator == NULL)
                return B_NO_MEMORY;

        *_cookie = iterator;
        return B_OK;
}


static status_t
ufs2_read_dir(fs_volume *_volume, fs_vnode *_node, void *_cookie,
                         struct dirent *dirent, size_t bufferSize, uint32 *_num)
{
        DirectoryIterator* iterator = (DirectoryIterator*)_cookie;
        Volume* volume = (Volume*)_volume->private_volume;

        uint32 maxCount = *_num;
        uint32 count = 0;

        while (count < maxCount
                        && (bufferSize >= sizeof(struct dirent) + B_FILE_NAME_LENGTH)) {
                size_t length = bufferSize - offsetof(struct dirent, d_name);
                ino_t iNodeNo;

                status_t status = iterator->GetNext(dirent->d_name, &length, &iNodeNo);
                if (status == B_ENTRY_NOT_FOUND)
                        break;
                if (status == B_BUFFER_OVERFLOW) {
                        if (count == 0)
                                return status;
                        break;
                }
                if (status != B_OK)
                        return status;

                dirent->d_dev = volume->ID();
                dirent->d_ino = iNodeNo;
                dirent->d_reclen = offsetof(struct dirent, d_name) + length + 1;
                bufferSize -= dirent->d_reclen;
                dirent = (struct dirent*)((uint8*)dirent + dirent->d_reclen);
                count++;
        }

        *_num = count;
        return B_OK;

}


static status_t
ufs2_rewind_dir(fs_volume * /*_volume*/, fs_vnode * /*node*/, void *_cookie)
{
        DirectoryIterator *iterator = (DirectoryIterator *)_cookie;
        return iterator->Rewind();
}


static status_t
ufs2_close_dir(fs_volume * /*_volume*/, fs_vnode * /*node*/,
                          void * /*_cookie*/)
{
        return B_OK;
}


static status_t
ufs2_free_dir_cookie(fs_volume *_volume, fs_vnode *_node, void *_cookie)
{
        delete (DirectoryIterator*)_cookie;
        return B_OK;
}


static status_t
ufs2_open_attr_dir(fs_volume *_volume, fs_vnode *_node, void **_cookie)
{
        return B_NOT_SUPPORTED;
}


static status_t
ufs2_close_attr_dir(fs_volume *_volume, fs_vnode *_node, void *cookie)
{
        return B_NOT_SUPPORTED;
}


static status_t
ufs2_free_attr_dir_cookie(fs_volume *_volume, fs_vnode *_node, void *_cookie)
{
        return B_NOT_SUPPORTED;
}


static status_t
ufs2_read_attr_dir(fs_volume *_volume, fs_vnode *_node,
                                  void *_cookie, struct dirent *dirent, size_t bufferSize, uint32 *_num)
{
        return B_NOT_SUPPORTED;
}


static status_t
ufs2_rewind_attr_dir(fs_volume *_volume, fs_vnode *_node, void *_cookie)
{
        return B_NOT_SUPPORTED;
}


/* attribute operations */
static status_t
ufs2_create_attr(fs_volume *_volume, fs_vnode *_node,
                                const char *name, uint32 type, int openMode, void **_cookie)
{
        return B_NOT_SUPPORTED;
}


static status_t
ufs2_open_attr(fs_volume *_volume, fs_vnode *_node, const char *name,
                          int openMode, void **_cookie)
{
        return B_NOT_SUPPORTED;
}


static status_t
ufs2_close_attr(fs_volume *_volume, fs_vnode *_node,
                           void *cookie)
{
        return B_NOT_SUPPORTED;
}


static status_t
ufs2_free_attr_cookie(fs_volume *_volume, fs_vnode *_node,
                                         void *cookie)
{
        return B_NOT_SUPPORTED;
}


static status_t
ufs2_read_attr(fs_volume *_volume, fs_vnode *_node, void *_cookie,
                          off_t pos, void *buffer, size_t *_length)
{
        return B_NOT_SUPPORTED;
}


static status_t
ufs2_write_attr(fs_volume *_volume, fs_vnode *_node, void *cookie,
                           off_t pos, const void *buffer, size_t *length)
{
        return B_NOT_SUPPORTED;
}


static status_t
ufs2_read_attr_stat(fs_volume *_volume, fs_vnode *_node,
                                   void *_cookie, struct stat *stat)
{
        return B_NOT_SUPPORTED;
}


static status_t
ufs2_write_attr_stat(fs_volume *_volume, fs_vnode *_node,
                                        void *cookie, const struct stat *stat, int statMask)
{
        return B_NOT_SUPPORTED;
}


static status_t
ufs2_rename_attr(fs_volume *_volume, fs_vnode *fromVnode,
                                const char *fromName, fs_vnode *toVnode, const char *toName)
{
        return B_NOT_SUPPORTED;
}


static status_t
ufs2_remove_attr(fs_volume *_volume, fs_vnode *vnode,
                                const char *name)
{
        return B_NOT_SUPPORTED;
}


//      #pragma mark -

static status_t
ufs2_std_ops(int32 op, ...)
{
        switch (op)
        {
        case B_MODULE_INIT:
#ifdef ufs2_DEBUGGER_COMMANDS
                // Perform nothing at the moment
                // add_debugger_commands();
#endif
                return B_OK;
        case B_MODULE_UNINIT:
#ifdef ufs2_DEBUGGER_COMMANDS
                // Perform nothing at the moment
                // remove_debugger_commands();
#endif
                return B_OK;

        default:
                return B_ERROR;
        }
}

fs_volume_ops gUfs2VolumeOps = {
        &ufs2_unmount,
        &ufs2_read_fs_info,
        NULL, //write_fs_info()
        NULL, // fs_sync,
        &ufs2_get_vnode,
};

fs_vnode_ops gufs2VnodeOps = {
        /* vnode operations */
        &ufs2_lookup,
        NULL, // ufs2_get_vnode_name - optional, and we can't do better than the
                  // fallback implementation, so leave as NULL.
        &ufs2_put_vnode,
        NULL, // ufs2_remove_vnode,

        /* VM file access */
        &ufs2_can_page,
        &ufs2_read_pages,
        NULL, // ufs2_write_pages,

        &ufs2_io, // io()
        NULL,   // cancel_io()

        &ufs2_get_file_map,

        &ufs2_ioctl,
        NULL,
        NULL, // fs_select
        NULL, // fs_deselect
        NULL, // fs_fsync,

        &ufs2_read_link,
        NULL, // fs_create_symlink,

        NULL, // fs_link,
        &ufs2_unlink,
        NULL, // fs_rename,

        &ufs2_access,
        &ufs2_read_stat,
        NULL, // fs_write_stat,
        NULL, // fs_preallocate

        /* file operations */
        NULL, // fs_create,
        &ufs2_open,
        &ufs2_close,
        &ufs2_free_cookie,
        &ufs2_read,
        NULL, //        fs_write,

        /* directory operations */
        &ufs2_create_dir,
        &ufs2_remove_dir,
        &ufs2_open_dir,
        &ufs2_close_dir,
        &ufs2_free_dir_cookie,
        &ufs2_read_dir,
        &ufs2_rewind_dir,

        /* attribute directory operations */
        &ufs2_open_attr_dir,
        &ufs2_close_attr_dir,
        &ufs2_free_attr_dir_cookie,
        &ufs2_read_attr_dir,
        &ufs2_rewind_attr_dir,

        /* attribute operations */
        &ufs2_create_attr,
        &ufs2_open_attr,
        &ufs2_close_attr,
        &ufs2_free_attr_cookie,
        &ufs2_read_attr,
        &ufs2_write_attr,
        &ufs2_read_attr_stat,
        &ufs2_write_attr_stat,
        &ufs2_rename_attr,
        &ufs2_remove_attr,
};


static file_system_module_info sufs2FileSystem = {
        {
                "file_systems/ufs2" B_CURRENT_FS_API_VERSION,
                0,
                ufs2_std_ops,
        },

        "ufs2",                    // short_name
        "Unix Filesystem 2", // pretty_name

        // DDM flags
        B_DISK_SYSTEM_SUPPORTS_CONTENT_NAME
        //      | B_DISK_SYSTEM_SUPPORTS_WRITING
        ,

        // scanning
        ufs2_identify_partition,
        ufs2_scan_partition,
        ufs2_free_identify_partition_cookie,
        NULL, // free_partition_content_cookie()

        &ufs2_mount,
};

module_info *modules[] = {
        (module_info *)&sufs2FileSystem,
        NULL,
};