/*
---------------------------------------------------------------------------
Open Asset Import Library (assimp)
---------------------------------------------------------------------------

Copyright (c) 2006-2017, assimp team


All rights reserved.

Redistribution and use of this software in source and binary forms,
with or without modification, are permitted provided that the following
conditions are met:

* Redistributions of source code must retain the above
  copyright notice, this list of conditions and the
  following disclaimer.

* Redistributions in binary form must reproduce the above
  copyright notice, this list of conditions and the
  following disclaimer in the documentation and/or other
  materials provided with the distribution.

* Neither the name of the assimp team, nor the names of its
  contributors may be used to endorse or promote products
  derived from this software without specific prior
  written permission of the assimp team.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
---------------------------------------------------------------------------
*/

/** @file IOSystem.hpp
 *  @brief File system wrapper for C++. Inherit this class to supply
 *  custom file handling logic to the Import library.
*/

#pragma once
#ifndef AI_IOSYSTEM_H_INC
#define AI_IOSYSTEM_H_INC

#ifndef __cplusplus
#   error This header requires C++ to be used. aiFileIO.h is the \
    corresponding C interface.
#endif

#include "types.h"

#include <vector>

namespace Assimp    {
class IOStream;

// ---------------------------------------------------------------------------
/** @brief CPP-API: Interface to the file system.
 *
 *  Derive an own implementation from this interface to supply custom file handling
 *  to the importer library. If you implement this interface, you also want to
 *  supply a custom implementation for IOStream.
 *
 *  @see Importer::SetIOHandler() 
 */
class ASSIMP_API IOSystem
#ifndef SWIG
    : public Intern::AllocateFromAssimpHeap
#endif
{
public:

    // -------------------------------------------------------------------
    /** @brief Default constructor.
     *
     *  Create an instance of your derived class and assign it to an
     *  #Assimp::Importer instance by calling Importer::SetIOHandler().
     */
    IOSystem();

    // -------------------------------------------------------------------
    /** @brief Virtual destructor.
     *
     *  It is safe to be called from within DLL Assimp, we're constructed
     *  on Assimp's heap.
     */
    virtual ~IOSystem();


public:

    // -------------------------------------------------------------------
    /** @brief For backward compatibility
     *  @see Exists(const char*)
     */
    AI_FORCE_INLINE bool Exists( const std::string& pFile) const;

    // -------------------------------------------------------------------
    /** @brief Tests for the existence of a file at the given path.
     *
     * @param pFile Path to the file
     * @return true if there is a file with this path, else false.
     */
    virtual bool Exists( const char* pFile) const = 0;

    // -------------------------------------------------------------------
    /** @brief Returns the system specific directory separator
     *  @return System specific directory separator
     */
    virtual char getOsSeparator() const = 0;

    // -------------------------------------------------------------------
    /** @brief Open a new file with a given path.
     *
     *  When the access to the file is finished, call Close() to release
     *  all associated resources (or the virtual dtor of the IOStream).
     *
     *  @param pFile Path to the file
     *  @param pMode Desired file I/O mode. Required are: "wb", "w", "wt",
     *         "rb", "r", "rt".
     *
     *  @return New IOStream interface allowing the lib to access
     *         the underlying file.
     *  @note When implementing this class to provide custom IO handling,
     *  you probably have to supply an own implementation of IOStream as well.
     */
    virtual IOStream* Open(const char* pFile,
        const char* pMode = "rb") = 0;

    // -------------------------------------------------------------------
    /** @brief For backward compatibility
     *  @see Open(const char*, const char*)
     */
    inline IOStream* Open(const std::string& pFile,
        const std::string& pMode = std::string("rb"));

    // -------------------------------------------------------------------
    /** @brief Closes the given file and releases all resources
     *    associated with it.
     *  @param pFile The file instance previously created by Open().
     */
    virtual void Close( IOStream* pFile) = 0;

    // -------------------------------------------------------------------
    /** @brief Compares two paths and check whether the point to
     *         identical files.
     *
     * The dummy implementation of this virtual member performs a
     * case-insensitive comparison of the given strings. The default IO
     * system implementation uses OS mechanisms to convert relative into
     * absolute paths, so the result can be trusted.
     * @param one First file
     * @param second Second file
     * @return true if the paths point to the same file. The file needn't
     *   be existing, however.
     */
    virtual bool ComparePaths (const char* one,
        const char* second) const;

    // -------------------------------------------------------------------
    /** @brief For backward compatibility
     *  @see ComparePaths(const char*, const char*)
     */
    inline bool ComparePaths (const std::string& one,
        const std::string& second) const;

    // -------------------------------------------------------------------
    /** @brief Pushes a new directory onto the directory stack.
     *  @param path Path to push onto the stack.
     *  @return True, when push was successful, false if path is empty.
     */
    virtual bool PushDirectory( const std::string &path );

    // -------------------------------------------------------------------
    /** @brief Returns the top directory from the stack.
     *  @return The directory on the top of the stack.
     *          Returns empty when no directory was pushed to the stack.
     */
    virtual const std::string &CurrentDirectory() const;

    // -------------------------------------------------------------------
    /** @brief Returns the number of directories stored on the stack.
     *  @return The number of directories of the stack.
     */
    virtual size_t StackSize() const;

    // -------------------------------------------------------------------
    /** @brief Pops the top directory from the stack.
     *  @return True, when a directory was on the stack. False if no
     *          directory was on the stack.
     */
    virtual bool PopDirectory();

private:
    std::vector<std::string> m_pathStack;
};

// ----------------------------------------------------------------------------
AI_FORCE_INLINE IOSystem::IOSystem() :
    m_pathStack()
{
    // empty
}

// ----------------------------------------------------------------------------
AI_FORCE_INLINE IOSystem::~IOSystem()
{
    // empty
}

// ----------------------------------------------------------------------------
// For compatibility, the interface of some functions taking a std::string was
// changed to const char* to avoid crashes between binary incompatible STL
// versions. This code her is inlined,  so it shouldn't cause any problems.
// ----------------------------------------------------------------------------

// ----------------------------------------------------------------------------
AI_FORCE_INLINE IOStream* IOSystem::Open(const std::string& pFile,
    const std::string& pMode)
{
    // NOTE:
    // For compatibility, interface was changed to const char* to
    // avoid crashes between binary incompatible STL versions
    return Open(pFile.c_str(),pMode.c_str());
}

// ----------------------------------------------------------------------------
AI_FORCE_INLINE bool IOSystem::Exists( const std::string& pFile) const
{
    // NOTE:
    // For compatibility, interface was changed to const char* to
    // avoid crashes between binary incompatible STL versions
    return Exists(pFile.c_str());
}

// ----------------------------------------------------------------------------
inline bool IOSystem::ComparePaths (const std::string& one,
    const std::string& second) const
{
    // NOTE:
    // For compatibility, interface was changed to const char* to
    // avoid crashes between binary incompatible STL versions
    return ComparePaths(one.c_str(),second.c_str());
}

// ----------------------------------------------------------------------------
inline bool IOSystem::PushDirectory( const std::string &path ) {
    if ( path.empty() ) {
        return false;
    }

    m_pathStack.push_back( path );

    return true;
}

// ----------------------------------------------------------------------------
inline const std::string &IOSystem::CurrentDirectory() const {
    if ( m_pathStack.empty() ) {
        static const std::string Dummy("");
        return Dummy;
    }
    return m_pathStack[ m_pathStack.size()-1 ];
}

// ----------------------------------------------------------------------------
inline size_t IOSystem::StackSize() const {
    return m_pathStack.size();
}

// ----------------------------------------------------------------------------
inline bool IOSystem::PopDirectory() {
    if ( m_pathStack.empty() ) {
        return false;
    }

    m_pathStack.pop_back();

    return true;
}

// ----------------------------------------------------------------------------

} //!ns Assimp

#endif //AI_IOSYSTEM_H_INC
