/******************************************************************************
 *
 * Project:  Hierarchical Data Format Release 5 (HDF5)
 * Authors:  Denis Nadeau <denis.nadeau@gmail.com>
 *           Sam Gillingham <gillingham.sam@gmail.com>
 *
 ******************************************************************************
 * Copyright (c) 2008-2018, Even Rouault <even.rouault at spatialys.com>
 *
 * SPDX-License-Identifier: MIT
 ****************************************************************************/

// This file contains the Virtual File Layer implementation that calls through
// to the VSI functions and should be included by HDF5 based drivers that wish
// to use the VFL for /vsi file system support.

#ifndef HDF5VFL_H_INCLUDED_
#define HDF5VFL_H_INCLUDED_

#include "cpl_port.h"

#include <algorithm>
#include <mutex>

#ifdef H5FD_FEAT_MEMMANAGE
#define HDF5_1_13_OR_LATER
#endif

// HDF5 >= 1.13.2
#ifdef H5FD_CLASS_VERSION
#if H5FD_CLASS_VERSION != 1
#error                                                                         \
    "HDF5_vsil_g needs to be adapted to the new layout of H5FD_class_t. Look at ${hdf5_prefix}/include/H5FDdevelop.h"
#endif
#endif

static std::mutex gMutex;
static hid_t hFileDriver = -1;

static H5FD_t *HDF5_vsil_open(const char *name, unsigned flags, hid_t fapl_id,
                              haddr_t maxaddr);
static herr_t HDF5_vsil_close(H5FD_t *_file);
static herr_t HDF5_vsil_query(const H5FD_t *_f1, unsigned long *flags);
static haddr_t HDF5_vsil_get_eoa(const H5FD_t *_file, H5FD_mem_t type);
static herr_t HDF5_vsil_set_eoa(H5FD_t *_file, H5FD_mem_t type, haddr_t addr);
static haddr_t HDF5_vsil_get_eof(const H5FD_t *_file, H5FD_mem_t type);
static herr_t HDF5_vsil_read(H5FD_t *_file, H5FD_mem_t type, hid_t fapl_id,
                             haddr_t addr, size_t size, void *buf);
static herr_t HDF5_vsil_write(H5FD_t *_file, H5FD_mem_t type, hid_t fapl_id,
                              haddr_t addr, size_t size, const void *buf);
static herr_t HDF5_vsil_truncate(H5FD_t *_file, hid_t dxpl_id, hbool_t closing);

static hid_t HDF5VFLGetFileDriver();
static void HDF5VFLUnloadFileDriver();

#define MAXADDR (((haddr_t)1 << (8 * sizeof(haddr_t) - 1)) - 1)

/* See https://support.hdfgroup.org/HDF5/doc/TechNotes/VFL.html */
static const H5FD_class_t HDF5_vsil_g = {
#ifdef H5FD_CLASS_VERSION
    H5FD_CLASS_VERSION,
#endif
#ifdef HDF5_1_13_OR_LATER
    /* value: 513 has been reserved with hdfgroup and is registered at:
     * https://portal.hdfgroup.org/pages/viewpage.action?pageId=74188097 */
    (H5FD_class_value_t)(513),
#endif
    "vsil",            /* name */
    MAXADDR,           /* maxaddr  */
    H5F_CLOSE_WEAK,    /* fc_degree  */
    nullptr,           /* terminate */
    nullptr,           /* sb_size  */
    nullptr,           /* sb_encode */
    nullptr,           /* sb_decode */
    0,                 /* fapl_size */
    nullptr,           /* fapl_get  */
    nullptr,           /* fapl_copy */
    nullptr,           /* fapl_free */
    0,                 /* dxpl_size */
    nullptr,           /* dxpl_copy */
    nullptr,           /* dxpl_free */
    HDF5_vsil_open,    /* open */
    HDF5_vsil_close,   /* close */
    nullptr,           /* cmp  */
    HDF5_vsil_query,   /* query */
    nullptr,           /* get_type_map */
    nullptr,           /* alloc */
    nullptr,           /* free */
    HDF5_vsil_get_eoa, /* get_eoa */
    HDF5_vsil_set_eoa, /* set_eoa */
    HDF5_vsil_get_eof, /* get_eof */
    nullptr,           /* get_handle */
    HDF5_vsil_read,    /* read */
    HDF5_vsil_write,   /* write */
#if H5FD_CLASS_VERSION == 1
    nullptr, /* read_vector */
    nullptr, /* write_vector */
    nullptr, /* read_selection */
    nullptr, /* write_selection */
#endif
    nullptr,            /* flush */
    HDF5_vsil_truncate, /* truncate */
    nullptr,            /* lock */
    nullptr,            /* unlock */
#ifdef HDF5_1_13_OR_LATER
    nullptr, /* del */
    nullptr, /* ctl */
#endif
    H5FD_FLMAP_DICHOTOMY /* fl_map */
};

typedef struct HDF5_vsil_t
{
    H5FD_t pub; /* must be first */
    VSILFILE *fp = nullptr;
    haddr_t eoa = 0;
    haddr_t eof = 0;
} HDF5_vsil_t;

static H5FD_t *HDF5_vsil_open(const char *name, unsigned flags,
                              hid_t /*fapl_id*/, haddr_t /*maxaddr*/)
{
    const char *openFlags = "rb";
    if ((H5F_ACC_RDWR & flags))
        openFlags = "rb+";
    if ((H5F_ACC_TRUNC & flags) || (H5F_ACC_CREAT & flags))
        openFlags = "wb+";

    VSILFILE *fp = VSIFOpenL(name, openFlags);
    if (!fp)
    {
        return nullptr;
    }
    if ((H5F_ACC_TRUNC & flags))
    {
        VSIFTruncateL(fp, 0);
    }

    HDF5_vsil_t *fh = new HDF5_vsil_t;
    memset(&fh->pub, 0, sizeof(fh->pub));
    if (!fh)
    {
        VSIFCloseL(fp);
        return nullptr;
    }
    fh->fp = fp;

    VSIFSeekL(fh->fp, 0, SEEK_END);
    fh->eof = static_cast<haddr_t>(VSIFTellL(fh->fp));

    return reinterpret_cast<H5FD_t *>(fh);
}

static herr_t HDF5_vsil_close(H5FD_t *_file)
{
    HDF5_vsil_t *fh = reinterpret_cast<HDF5_vsil_t *>(_file);
    int ret = VSIFCloseL(fh->fp);
    delete fh;
    return ret;
}

static herr_t HDF5_vsil_query(const H5FD_t *, unsigned long *flags /* out */)
{
    *flags = H5FD_FEAT_AGGREGATE_METADATA | H5FD_FEAT_ACCUMULATE_METADATA |
             H5FD_FEAT_DATA_SIEVE | H5FD_FEAT_AGGREGATE_SMALLDATA;
    return 0;
}

static haddr_t HDF5_vsil_get_eoa(const H5FD_t *_file, H5FD_mem_t /*type*/)
{
    const HDF5_vsil_t *fh = reinterpret_cast<const HDF5_vsil_t *>(_file);
    return fh->eoa;
}

static herr_t HDF5_vsil_set_eoa(H5FD_t *_file, H5FD_mem_t /*type*/,
                                haddr_t addr)
{
    HDF5_vsil_t *fh = reinterpret_cast<HDF5_vsil_t *>(_file);
    fh->eoa = addr;
    return 0;
}

static haddr_t HDF5_vsil_get_eof(const H5FD_t *_file, H5FD_mem_t /* type */
)
{
    const HDF5_vsil_t *fh = reinterpret_cast<const HDF5_vsil_t *>(_file);
    return fh->eof;
}

static herr_t HDF5_vsil_read(H5FD_t *_file, H5FD_mem_t /* type */,
                             hid_t /* dxpl_id */, haddr_t addr, size_t size,
                             void *buf /*out*/)
{
    HDF5_vsil_t *fh = reinterpret_cast<HDF5_vsil_t *>(_file);
    VSIFSeekL(fh->fp, static_cast<vsi_l_offset>(addr), SEEK_SET);
    return VSIFReadL(buf, size, 1, fh->fp) == 1 ? 0 : -1;
}

static herr_t HDF5_vsil_write(H5FD_t *_file, H5FD_mem_t /* type */,
                              hid_t /* dxpl_id */, haddr_t addr, size_t size,
                              const void *buf /*out*/)
{
    HDF5_vsil_t *fh = reinterpret_cast<HDF5_vsil_t *>(_file);
    VSIFSeekL(fh->fp, static_cast<vsi_l_offset>(addr), SEEK_SET);
    int ret = VSIFWriteL(buf, size, 1, fh->fp) == 1 ? 0 : -1;
    fh->eof = std::max(fh->eof, static_cast<haddr_t>(VSIFTellL(fh->fp)));
    return ret;
}

static herr_t HDF5_vsil_truncate(H5FD_t *_file, hid_t /* dxpl_id*/,
                                 hbool_t /*closing*/)
{
    HDF5_vsil_t *fh = reinterpret_cast<HDF5_vsil_t *>(_file);
    if (fh->eoa != fh->eof)
    {
        if (VSIFTruncateL(fh->fp, fh->eoa) < 0)
        {
            return -1;
        }
        fh->eof = fh->eoa;
    }
    return 0;
}

/************************************************************************/
/*                       HDF5VFLGetFileDriver()                         */
/************************************************************************/

static hid_t HDF5VFLGetFileDriver()
{
    std::lock_guard<std::mutex> oLock(gMutex);
    if (hFileDriver < 0)
    {
        hFileDriver = H5FDregister(&HDF5_vsil_g);
#if H5E_auto_t_vers == 2
        // also, don't print error messages from KEA driver.
        // (which uses H5E_auto_t_vers=2 - the default, hdf uses 1 for some
        // reason). These tend to be meaningless - ie no GCP's found etc. They
        // didn't seem to be shown when we didn't use the VFL layer
        // - maybe VFL turns them on?
        H5Eset_auto(H5E_DEFAULT, nullptr, nullptr);
#endif
    }
    return hFileDriver;
}

/************************************************************************/
/*                     HDF5VFLUnloadFileDriver()                        */
/************************************************************************/

static void HDF5VFLUnloadFileDriver()
{
    {
        std::lock_guard<std::mutex> oLock(gMutex);
        if (hFileDriver >= 0)
        {
            H5FDunregister(hFileDriver);
            hFileDriver = -1;
        }
    }
}

#endif /* HDF5VFL_H_INCLUDED_ */
