// Copyright (C) 2012 Kornel Kisielewicz
// This file is part of NV Libraries.
// For conditions of distribution and use, see copyright notice in nv.hh
#include "nv/common.hh"
#include "nv/library.hh"

#include <string.h>

#if NV_PLATFORM == NV_WINDOWS
#   define WIN32_LEAN_AND_MEAN
#   include <windows.h>
#   define NV_LIB_EXT ".dll"
#   define NV_LIB_HANDLE HMODULE
#   define NV_LIB_OPEN( name ) LoadLibraryEx( name, NULL, LOAD_WITH_ALTERED_SEARCH_PATH )
#   define NV_LIB_GET( handle, name ) GetProcAddress( handle, name )
#   define NV_LIB_CLOSE( name ) !FreeLibrary( name )
#elif NV_PLATFORM == NV_LINUX
#   include <dlfcn.h>
#   define NV_LIB_EXT ".so"
#   define NV_LIB_HANDLE void*
#   define NV_LIB_OPEN( name ) dlopen( name, RTLD_LAZY | RTLD_GLOBAL)
#   define NV_LIB_GET( handle, name ) dlsym( handle, name )
#   define NV_LIB_CLOSE( name ) dlclose( name )
#elif NV_PLATFORM == NV_APPLE
#   include "macUtils.h"
#   include <dlfcn.h>
#   define NV_LIB_EXT ".dylib"
#   define NV_LIB_HANDLE CFBundleRef
#   define NV_LIB_OPEN( name ) mac_loadExeBundle( name )
#   define NV_LIB_GET( handle, name ) mac_getBundleSym( handle, name )
#   define NV_LIB_CLOSE( name ) mac_unloadExeBundle( name )
#endif

#include "nv/logging.hh"

using namespace nv;

library::library( const std::string& name ) 
    : m_name( name )
{
    m_handle = NULL;
    open();
}

void library::open( const std::string& name )
{
	m_name = name;
	open();
}

const std::string& library::get_name() const
{
    return m_name;
}

void library::open()
{
    if ( m_handle != NULL )
    {
        return;
    }
    NV_LOG( LOG_NOTICE, "library : loading '" + m_name + "'..." );

    std::string name = m_name;
    std::string ext  = NV_LIB_EXT;
    size_t ext_len   = ext.length();

    if ( name.length() < ext_len || name.substr( name.length() - ext_len, ext_len ) != ext ) 
    {
        name += ext;
    }

    m_handle = (void*)NV_LIB_OPEN( name.c_str() );

    if ( m_handle == NULL )
    {
        NV_THROW( library_error, "Can't load library!", name );
    }
    NV_LOG( LOG_NOTICE, "library : '" + name + "' loaded." );
}

void* library::get( const std::string& symbol )
{
	void* result = (void*) NV_LIB_GET( (NV_LIB_HANDLE) m_handle, symbol.c_str() );
    if ( !result )
    {
        NV_THROW( library_error, "Can't find symbol " + symbol + "!", m_name );
    }
	return result;
}



void library::close()
{
    if ( NV_LIB_CLOSE( (NV_LIB_HANDLE)m_handle ) )
    {
        NV_LOG( LOG_ERROR, "library : can't close library '" + m_name + "'!" );
    }
    m_handle = NULL;
    NV_LOG( LOG_NOTICE, "library : '" + m_name + "' closed." );
}

library::~library()
{
    if ( m_handle != NULL )
    {
        close();
    }
}

std::string library::get_error()
{
#if NV_PLATFORM == NV_WINDOWS
    // We do hate WinAPI for code like this, don't we?
    LPVOID buffer;
    FormatMessage( FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
        NULL, GetLastError(), MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPTSTR) &buffer, 0, NULL );
    std::string msg( (char*)buffer );
    LocalFree( buffer );
    return msg;
#elif NV_PLATFORM == NV_LINUX || NV_PLATFORM == NV_APPLE
    return std::string(dlerror());
#else
    return std::string("");
#endif
}