#include "core.h"
#include "filesystem.h"
#include "module.h"

#if defined(_WINDOWS)
#include <windows.h>

static bool throw_win32(void)
{
	return false;
}

bool MCModuleLoad(const char *p_filename, MCModuleRef& r_module)
{
	bool t_success;
	t_success = true;

	void *t_native_filename;
	t_native_filename = nil;
	if (t_success)
		t_success = MCFileSystemPathToNative(p_filename, t_native_filename);

	HMODULE t_module;
	t_module = nil;
	if (t_success)
	{
		t_module = LoadLibraryW((LPCWSTR)t_native_filename);
		if (t_module == nil)
			t_success = throw_win32();
	}

	if (t_success)
		r_module = (MCModuleRef)t_module;

	MCMemoryDeallocate(t_native_filename);

	return t_success;
}

void MCModuleUnload(MCModuleRef self)
{
	if (self == nil)
		return;

	FreeLibrary((HMODULE)self);
}

bool MCModuleLookupSymbol(MCModuleRef self, const char *p_symbol, void **r_address)
{
	void *t_address;
	t_address = GetProcAddress((HMODULE)self, p_symbol);
	*r_address = t_address;
	return true;
}

bool MCModuleGetFilename(MCModuleRef p_module, char*& r_path)
{
	bool t_success;
	t_success = true;

	// For some unfathomable reason, it is not possible find out how big a
	// buffer you might need for a module file name. Instead we loop until
	// we are sure we have the whole thing.
	unichar_t *t_wpath;
	uint32_t t_wpath_length;
	t_wpath_length = 0;
	t_wpath = nil;
	while(t_success)
	{
		t_wpath_length += 256;
		MCMemoryDeleteArray(t_wpath);

		if (t_success)
			t_success = MCMemoryNewArray(t_wpath_length, t_wpath);

		DWORD t_result;
		t_result = 0;
		if (t_success)
		{
			// If the buffer is too small, the result will equal the input
			// buffer size.
			t_result = GetModuleFileNameW((HMODULE)p_module, t_wpath, t_wpath_length);
			if (t_result == 0)
				t_success = false;
			else if (t_result == t_wpath_length)
				continue;
		}

		if (t_success)
			break;
	}

	// Convert the unicode string to UTF-8.
	if (t_success)
		t_success = MCFileSystemPathFromNative(t_wpath, r_path);

	MCMemoryDeleteArray(t_wpath);

	return t_success;
}

#elif defined(_LINUX)
#include <dlfcn.h>

bool MCModuleLoad(const char *p_filename, MCModuleRef& r_module)
{
	MCModuleRef t_module;
	t_module = (void *)dlopen(p_filename, (RTLD_NOW | RTLD_LOCAL));
	if (t_module == nil)
		return false;

	r_module = t_module;

	return true;
}

void MCModuleUnload(MCModuleRef self)
{
	if (self != nil)
		dlclose(self);
}

bool MCModuleLookupSymbol(MCModuleRef self, const char *p_symbol, void **r_address)
{
	void *t_address;
	t_address = dlsym(self, p_symbol);
	if (t_address == nil)
		return false;

	*r_address = t_address;

	return true;
}

bool MCModuleGetFilename(MCModuleRef p_module, char*& r_path)
{
	Dl_info t_info;
	if (p_module == nil && dladdr((void *)MCModuleGetFilename, &t_info) != 0)
		return MCCStringClone(t_info . dli_fname, r_path);

	return false;
}
#elif defined(_MACOSX)
#include <dlfcn.h>
#include <CoreFoundation/CoreFoundation.h>

bool MCModuleLoad(const char *p_filename, MCModuleRef& r_module)
{
	MCModuleRef t_module;
	if (MCCStringEndsWith(p_filename, ".dylib"))
	{
		t_module = (void *)dlopen(p_filename, (RTLD_NOW | RTLD_LOCAL));
		if (t_module == nil)
			return false;
	}
	else
	{
		CFURLRef t_url;
		t_url = CFURLCreateFromFileSystemRepresentation(kCFAllocatorDefault, (const UInt8 *)p_filename, MCCStringLength(p_filename), TRUE);
		if (t_url != nil)
		{
			t_module = (void *)CFBundleCreate(kCFAllocatorDefault, t_url);
			if (t_module != nil)
				t_module = (void *)((uintptr_t)t_module | 1);
			CFRelease(t_url);
		}
		
		if (t_module == nil)
			return false;
	}
	
	r_module = t_module;
	
	return true;
}

void MCModuleUnload(MCModuleRef self)
{
	if (self == nil)
		return;
	
	if (((uintptr_t)self & 1) == 0)
		dlclose(self);
	else
		CFRelease((CFBundleRef)((uintptr_t)self & ~1));
}

bool MCModuleLookupSymbol(MCModuleRef self, const char *p_symbol, void **r_address)
{
	if (self == nil)
		return false;
	
	void *t_address;
	if (((uintptr_t)self & 1) == 0)
	{
		t_address = dlsym(self, p_symbol);
		if (t_address == nil)
			return false;
	}
	else
	{
		CFStringRef t_symbol;
		if (!MCCStringToCFString(p_symbol, t_symbol))
			return false;
		t_address = CFBundleGetFunctionPointerForName((CFBundleRef)((uintptr_t)self & ~1), t_symbol);
		CFRelease(t_symbol);
		
		if (t_address == nil)
			return false;
	}
	
	*r_address = t_address;
	
	return true;
}

bool MCModuleGetFilename(MCModuleRef p_module, char*& r_path)
{
	Dl_info t_info;
	if (p_module == nil && dladdr((void *)MCModuleGetFilename, &t_info) != 0)
		return MCCStringClone(t_info . dli_fname, r_path);
	
	return false;
}
#endif