// Copyright (C) 2012-2015 ChaosForge Ltd
// http://chaosforge.org/
//
// This file is part of Nova libraries. 
// For conditions of distribution and use, see copying.txt file in root folder.

#include "nv/core/library.hh"

#if NV_PLATFORM == NV_WINDOWS
#   define WIN32_LEAN_AND_MEAN
#   include <windows.h>
#   define NV_LIB_EXT ".dll"
#   define NV_LIB_OPEN( name ) static_cast<void*>( LoadLibraryEx( name, NULL, LOAD_WITH_ALTERED_SEARCH_PATH ) )
#   define NV_LIB_GET( handle, name ) reinterpret_cast<void*>( GetProcAddress( static_cast<HMODULE>( handle ), name ) )
#   define NV_LIB_CLOSE( handle ) ( FreeLibrary( static_cast<HMODULE>( handle ) ) != 0 )
#elif NV_PLATFORM == NV_LINUX || NV_PLATFORM == NV_APPLE
#   include <dlfcn.h>
#   define NV_LIB_EXT ".so"
#   define NV_LIB_OPEN( name ) dlopen( name, RTLD_LAZY | RTLD_GLOBAL)
#   define NV_LIB_GET( handle, name ) dlsym( static_cast<void*>( handle ), name )
#   define NV_LIB_CLOSE( handle ) ( dlclose( static_cast<void*>( handle ) ) == 0 )
#elif NV_PLATFORM == NV_APPLE
#   include "macUtils.h"
#   include <dlfcn.h>
#   define NV_LIB_EXT ".dylib"
#   define NV_LIB_OPEN( name ) mac_loadExeBundle( name )
#   define NV_LIB_GET( handle, name ) mac_getBundleSym( handle, name )
#   define NV_LIB_CLOSE( handle ) ( mac_unloadExeBundle( handle ) == 0 )
#endif

#include "nv/core/logging.hh"

using namespace nv;

library::library() 
    : m_handle( nullptr ), m_name()
{
}

void library::open( string_view name )
{
	m_name.assign( name.data(), name.size() );
	if ( !open() )
	{
		m_handle = nullptr;
		NV_LOG_CRITICAL( "library \"", name, "\" : failed to load!" );
		NV_ABORT( "Can't load library!" );
	}
}

bool nv::library::try_open( string_view name )
{
	m_name.assign( name.data(), name.size() );
	if ( !open() )
	{
		m_handle = nullptr;
		return false;
	}
	return true;
}

string_view library::get_name() const
{
    return string_view( m_name );
}

bool library::open( )
{
    if ( m_handle != NULL )
    {
        return true;
    }
    NV_LOG_NOTICE( "library \"", string_view( m_name ), "\" : loading..." );

	std::string name = m_name;
	string_view ext( NV_LIB_EXT );

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

    m_handle = NV_LIB_OPEN( name.c_str() );

    if ( m_handle == NULL )
    {
		NV_LOG_NOTICE( "library \"", string_view( name ), "\" : failed to open!" );
		return false;
    }
    NV_LOG_NOTICE( "library \"", string_view( name ), "\" : loaded." );
	return true;
}

void* library::get( string_view symbol )
{
	void* result = NV_LIB_GET( m_handle, symbol.data() );
    if ( !result )
    {
		NV_LOG_CRITICAL( "library \"", string_view( m_name ), "\" : can't find symbol \"", symbol, "\"" );
		NV_ABORT( "Library symbol load failed!" );
    }
	return result;
}

void* nv::library::try_get( string_view symbol )
{
	return NV_LIB_GET( m_handle, symbol.data() );
}

bool library::is_open() const
{
	return m_handle != nullptr;
}

void library::close()
{
    if ( ! NV_LIB_CLOSE( m_handle ) )
    {
        NV_LOG_ERROR( "library \"", string_view( m_name ), "\" : can't close library!" );
    }
    m_handle = nullptr;
}

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

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