/**
 * WinPR: Windows Portable Runtime
 * Unicode Conversion (CRT)
 *
 * Copyright 2012 Marc-Andre Moreau <marcandre.moreau@gmail.com>
 * Copyright 2022 Armin Novak <anovak@thincast.com>
 * Copyright 2022 Thincast Technologies GmbH
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <winpr/config.h>
#include <winpr/assert.h>

#include <errno.h>
#include <wctype.h>

#include <winpr/crt.h>
#include <winpr/error.h>
#include <winpr/print.h>

#ifndef MIN
#define MIN(a, b) (a) < (b) ? (a) : (b)
#endif

#ifndef _WIN32

#include "unicode.h"

#include "../log.h"
#define TAG WINPR_TAG("unicode")

/**
 * Notes on cross-platform Unicode portability:
 *
 * Unicode has many possible Unicode Transformation Format (UTF) encodings,
 * where some of the most commonly used are UTF-8, UTF-16 and sometimes UTF-32.
 *
 * The number in the UTF encoding name (8, 16, 32) refers to the number of bits
 * per code unit. A code unit is the minimal bit combination that can represent
 * a unit of encoded text in the given encoding. For instance, UTF-8 encodes
 * the English alphabet using 8 bits (or one byte) each, just like in ASCII.
 *
 * However, the total number of code points (values in the Unicode codespace)
 * only fits completely within 32 bits. This means that for UTF-8 and UTF-16,
 * more than one code unit may be required to fully encode a specific value.
 * UTF-8 and UTF-16 are variable-width encodings, while UTF-32 is fixed-width.
 *
 * UTF-8 has the advantage of being backwards compatible with ASCII, and is
 * one of the most commonly used Unicode encoding.
 *
 * UTF-16 is used everywhere in the Windows API. The strategy employed by
 * Microsoft to provide backwards compatibility in their API was to create
 * an ANSI and a Unicode version of the same function, ending with A (ANSI)
 * and W (Wide character, or UTF-16 Unicode). In headers, the original
 * function name is replaced by a macro that defines to either the ANSI
 * or Unicode version based on the definition of the _UNICODE macro.
 *
 * UTF-32 has the advantage of being fixed width, but wastes a lot of space
 * for English text (4x more than UTF-8, 2x more than UTF-16).
 *
 * In C, wide character strings are often defined with the wchar_t type.
 * Many functions are provided to deal with those wide character strings,
 * such as wcslen (strlen equivalent) or wprintf (printf equivalent).
 *
 * This may lead to some confusion, since many of these functions exist
 * on both Windows and Linux, but they are *not* the same!
 *
 * This sample hello world is a good example:
 *
 * #include <wchar.h>
 *
 * wchar_t hello[] = L"Hello, World!\n";
 *
 * int main(int argc, char** argv)
 * {
 * 	wprintf(hello);
 * 	wprintf(L"sizeof(wchar_t): %d\n", sizeof(wchar_t));
 * 	return 0;
 * }
 *
 * There is a reason why the sample prints the size of the wchar_t type:
 * On Windows, wchar_t is two bytes (UTF-16), while on most other systems
 * it is 4 bytes (UTF-32). This means that if you write code on Windows,
 * use L"" to define a string which is meant to be UTF-16 and not UTF-32,
 * you will have a little surprise when trying to port your code to Linux.
 *
 * Since the Windows API uses UTF-16, not UTF-32, WinPR defines the WCHAR
 * type to always be 2-bytes long and uses it instead of wchar_t. Do not
 * ever use wchar_t with WinPR unless you know what you are doing.
 *
 * As for L"", it is unfortunately unusable in a portable way, unless a
 * special option is passed to GCC to define wchar_t as being two bytes.
 * For string constants that must be UTF-16, it is a pain, but they can
 * be defined in a portable way like this:
 *
 * WCHAR hello[] = { 'H','e','l','l','o','\0' };
 *
 * Such strings cannot be passed to native functions like wcslen(), which
 * may expect a different wchar_t size. For this reason, WinPR provides
 * _wcslen, which expects UTF-16 WCHAR strings on all platforms.
 *
 */

/*
 * Conversion to Unicode (UTF-16)
 * MultiByteToWideChar: http://msdn.microsoft.com/en-us/library/windows/desktop/dd319072/
 *
 * cbMultiByte is an input size in bytes (BYTE)
 * cchWideChar is an output size in wide characters (WCHAR)
 *
 * Null-terminated UTF-8 strings:
 *
 * cchWideChar *cannot* be assumed to be cbMultiByte since UTF-8 is variable-width!
 *
 * Instead, obtain the required cchWideChar output size like this:
 * cchWideChar = MultiByteToWideChar(CP_UTF8, 0, (LPCSTR) lpMultiByteStr, -1, NULL, 0);
 *
 * A value of -1 for cbMultiByte indicates that the input string is null-terminated,
 * and the null terminator *will* be processed. The size returned by MultiByteToWideChar
 * will therefore include the null terminator. Equivalent behavior can be obtained by
 * computing the length in bytes of the input buffer, including the null terminator:
 *
 * cbMultiByte = strlen((char*) lpMultiByteStr) + 1;
 *
 * An output buffer of the proper size can then be allocated:
 *
 * lpWideCharStr = (LPWSTR) malloc(cchWideChar * sizeof(WCHAR));
 *
 * Since cchWideChar is an output size in wide characters, the actual buffer size is:
 * (cchWideChar * sizeof(WCHAR)) or (cchWideChar * 2)
 *
 * Finally, perform the conversion:
 *
 * cchWideChar = MultiByteToWideChar(CP_UTF8, 0, (LPCSTR) lpMultiByteStr, -1, lpWideCharStr,
 * cchWideChar);
 *
 * The value returned by MultiByteToWideChar corresponds to the number of wide characters written
 * to the output buffer, and should match the value obtained on the first call to
 * MultiByteToWideChar.
 *
 */

int MultiByteToWideChar(UINT CodePage, DWORD dwFlags, LPCSTR lpMultiByteStr, int cbMultiByte,
                        LPWSTR lpWideCharStr, int cchWideChar)
{
	return int_MultiByteToWideChar(CodePage, dwFlags, lpMultiByteStr, cbMultiByte, lpWideCharStr,
	                               cchWideChar);
}

/*
 * Conversion from Unicode (UTF-16)
 * WideCharToMultiByte: http://msdn.microsoft.com/en-us/library/windows/desktop/dd374130/
 *
 * cchWideChar is an input size in wide characters (WCHAR)
 * cbMultiByte is an output size in bytes (BYTE)
 *
 * Null-terminated UTF-16 strings:
 *
 * cbMultiByte *cannot* be assumed to be cchWideChar since UTF-8 is variable-width!
 *
 * Instead, obtain the required cbMultiByte output size like this:
 * cbMultiByte = WideCharToMultiByte(CP_UTF8, 0, (LPCWSTR) lpWideCharStr, -1, NULL, 0, NULL, NULL);
 *
 * A value of -1 for cbMultiByte indicates that the input string is null-terminated,
 * and the null terminator *will* be processed. The size returned by WideCharToMultiByte
 * will therefore include the null terminator. Equivalent behavior can be obtained by
 * computing the length in bytes of the input buffer, including the null terminator:
 *
 * cchWideChar = _wcslen((WCHAR*) lpWideCharStr) + 1;
 *
 * An output buffer of the proper size can then be allocated:
 * lpMultiByteStr = (LPSTR) malloc(cbMultiByte);
 *
 * Since cbMultiByte is an output size in bytes, it is the same as the buffer size
 *
 * Finally, perform the conversion:
 *
 * cbMultiByte = WideCharToMultiByte(CP_UTF8, 0, (LPCWSTR) lpWideCharStr, -1, lpMultiByteStr,
 * cbMultiByte, NULL, NULL);
 *
 * The value returned by WideCharToMultiByte corresponds to the number of bytes written
 * to the output buffer, and should match the value obtained on the first call to
 * WideCharToMultiByte.
 *
 */

int WideCharToMultiByte(UINT CodePage, DWORD dwFlags, LPCWSTR lpWideCharStr, int cchWideChar,
                        LPSTR lpMultiByteStr, int cbMultiByte, LPCSTR lpDefaultChar,
                        LPBOOL lpUsedDefaultChar)
{
	return int_WideCharToMultiByte(CodePage, dwFlags, lpWideCharStr, cchWideChar, lpMultiByteStr,
	                               cbMultiByte, lpDefaultChar, lpUsedDefaultChar);
}

#endif

/**
 * ConvertToUnicode is a convenience wrapper for MultiByteToWideChar:
 *
 * If the lpWideCharStr parameter for the converted string points to NULL
 * or if the cchWideChar parameter is set to 0 this function will automatically
 * allocate the required memory which is guaranteed to be null-terminated
 * after the conversion, even if the source c string isn't.
 *
 * If the cbMultiByte parameter is set to -1 the passed lpMultiByteStr must
 * be null-terminated and the required length for the converted string will be
 * calculated accordingly.
 */
#if defined(WITH_WINPR_DEPRECATED)
int ConvertToUnicode(UINT CodePage, DWORD dwFlags, LPCSTR lpMultiByteStr, int cbMultiByte,
                     LPWSTR* lpWideCharStr, int cchWideChar)
{
	int status;
	BOOL allocate = FALSE;

	if (!lpMultiByteStr)
		return 0;

	if (!lpWideCharStr)
		return 0;

	if (cbMultiByte == -1)
	{
		size_t len = strnlen(lpMultiByteStr, INT_MAX);
		if (len >= INT_MAX)
			return 0;
		cbMultiByte = (int)(len + 1);
	}

	if (cchWideChar == 0)
	{
		cchWideChar = MultiByteToWideChar(CodePage, dwFlags, lpMultiByteStr, cbMultiByte, NULL, 0);
		allocate = TRUE;
	}
	else if (!(*lpWideCharStr))
		allocate = TRUE;

	if (cchWideChar < 1)
		return 0;

	if (allocate)
	{
		*lpWideCharStr = (LPWSTR)calloc(cchWideChar + 1, sizeof(WCHAR));

		if (!(*lpWideCharStr))
		{
			// SetLastError(ERROR_INSUFFICIENT_BUFFER);
			return 0;
		}
	}

	status = MultiByteToWideChar(CodePage, dwFlags, lpMultiByteStr, cbMultiByte, *lpWideCharStr,
	                             cchWideChar);

	if (status != cchWideChar)
	{
		if (allocate)
		{
			free(*lpWideCharStr);
			*lpWideCharStr = NULL;
			status = 0;
		}
	}

	return status;
}
#endif

/**
 * ConvertFromUnicode is a convenience wrapper for WideCharToMultiByte:
 *
 * If the lpMultiByteStr parameter for the converted string points to NULL
 * or if the cbMultiByte parameter is set to 0 this function will automatically
 * allocate the required memory which is guaranteed to be null-terminated
 * after the conversion, even if the source unicode string isn't.
 *
 * If the cchWideChar parameter is set to -1 the passed lpWideCharStr must
 * be null-terminated and the required length for the converted string will be
 * calculated accordingly.
 */
#if defined(WITH_WINPR_DEPRECATED)
int ConvertFromUnicode(UINT CodePage, DWORD dwFlags, LPCWSTR lpWideCharStr, int cchWideChar,
                       LPSTR* lpMultiByteStr, int cbMultiByte, LPCSTR lpDefaultChar,
                       LPBOOL lpUsedDefaultChar)
{
	int status;
	BOOL allocate = FALSE;

	if (!lpWideCharStr)
		return 0;

	if (!lpMultiByteStr)
		return 0;

	if (cchWideChar == -1)
		cchWideChar = (int)(_wcslen(lpWideCharStr) + 1);

	if (cbMultiByte == 0)
	{
		cbMultiByte =
		    WideCharToMultiByte(CodePage, dwFlags, lpWideCharStr, cchWideChar, NULL, 0, NULL, NULL);
		allocate = TRUE;
	}
	else if (!(*lpMultiByteStr))
		allocate = TRUE;

	if (cbMultiByte < 1)
		return 0;

	if (allocate)
	{
		*lpMultiByteStr = (LPSTR)calloc(1, cbMultiByte + 1);

		if (!(*lpMultiByteStr))
		{
			// SetLastError(ERROR_INSUFFICIENT_BUFFER);
			return 0;
		}
	}

	status = WideCharToMultiByte(CodePage, dwFlags, lpWideCharStr, cchWideChar, *lpMultiByteStr,
	                             cbMultiByte, lpDefaultChar, lpUsedDefaultChar);

	if ((status != cbMultiByte) && allocate)
	{
		status = 0;
	}

	if ((status <= 0) && allocate)
	{
		free(*lpMultiByteStr);
		*lpMultiByteStr = NULL;
	}

	return status;
}
#endif

/**
 * Swap Unicode byte order (UTF16LE <-> UTF16BE)
 */

void ByteSwapUnicode(WCHAR* wstr, size_t length)
{
	WINPR_ASSERT(wstr || (length == 0));

	for (size_t x = 0; x < length; x++)
		wstr[x] = _byteswap_ushort(wstr[x]);
}

SSIZE_T ConvertWCharToUtf8(const WCHAR* wstr, char* str, size_t len)
{
	if (!wstr)
		return 0;

	const int rc =
	    WideCharToMultiByte(CP_UTF8, 0, wstr, -1, str, (int)MIN(INT32_MAX, len), NULL, NULL);
	if (rc <= 0)
		return rc;
	else if (rc == len)
	{
		if (str && (str[rc - 1] != '\0'))
			return rc;
	}
	return rc - 1;
}

SSIZE_T ConvertWCharNToUtf8(const WCHAR* wstr, size_t wlen, char* str, size_t len)
{
	BOOL isNullTerminated = FALSE;
	if (wlen == 0)
		return 0;

	WINPR_ASSERT(wstr);
	size_t iwlen = _wcsnlen(wstr, wlen);

	if (wlen > INT32_MAX)
		return -1;

	if (iwlen < wlen)
	{
		isNullTerminated = TRUE;
		iwlen++;
	}
	const int rc = WideCharToMultiByte(CP_UTF8, 0, wstr, (int)iwlen, str, (int)MIN(INT32_MAX, len),
	                                   NULL, NULL);
	if ((rc <= 0) || ((len > 0) && (rc > len)))
		return -1;
	else if (!isNullTerminated)
	{
		if (str && (rc < len))
			str[rc] = '\0';
		return rc;
	}
	else if (rc == len)
	{
		if (str && (str[rc - 1] != '\0'))
			return rc;
	}
	return rc - 1;
}

SSIZE_T ConvertMszWCharNToUtf8(const WCHAR* wstr, size_t wlen, char* str, size_t len)
{
	if (len == 0)
		return 0;

	WINPR_ASSERT(str);

	if (wlen > INT32_MAX)
		return -1;

	const int iwlen = MIN(INT32_MAX, len);
	const int rc = WideCharToMultiByte(CP_UTF8, 0, wstr, (int)wlen, str, (int)iwlen, NULL, NULL);
	if ((rc <= 0) || ((len > 0) && (rc > iwlen)))
		return -1;

	return rc;
}

SSIZE_T ConvertUtf8ToWChar(const char* str, WCHAR* wstr, size_t wlen)
{
	if (!str)
		return 0;

	const int iwlen = MIN(INT32_MAX, wlen);
	const int rc = MultiByteToWideChar(CP_UTF8, 0, str, -1, wstr, iwlen);
	if (rc <= 0)
		return rc;
	else if (iwlen == rc)
	{
		if (wstr && (wstr[rc - 1] != '\0'))
			return rc;
	}
	return rc - 1;
}

SSIZE_T ConvertUtf8NToWChar(const char* str, size_t len, WCHAR* wstr, size_t wlen)
{
	size_t ilen = strnlen(str, len);
	BOOL isNullTerminated = FALSE;
	if (len == 0)
		return 0;

	WINPR_ASSERT(str);

	if (len > INT32_MAX)
		return -1;
	if (ilen < len)
	{
		isNullTerminated = TRUE;
		ilen++;
	}

	const int iwlen = MIN(INT32_MAX, wlen);
	const int rc = MultiByteToWideChar(CP_UTF8, 0, str, (int)ilen, wstr, (int)iwlen);
	if ((rc <= 0) || ((wlen > 0) && (rc > iwlen)))
		return -1;
	if (!isNullTerminated)
	{
		if (wstr && (rc < iwlen))
			wstr[rc] = '\0';
		return rc;
	}
	else if (rc == iwlen)
	{
		if (wstr && (wstr[rc - 1] != '\0'))
			return rc;
	}
	return rc - 1;
}

SSIZE_T ConvertMszUtf8NToWChar(const char* str, size_t len, WCHAR* wstr, size_t wlen)
{
	if (len == 0)
		return 0;

	WINPR_ASSERT(str);

	if (len > INT32_MAX)
		return -1;

	const int iwlen = MIN(INT32_MAX, wlen);
	const int rc = MultiByteToWideChar(CP_UTF8, 0, str, (int)len, wstr, (int)iwlen);
	if ((rc <= 0) || ((wlen > 0) && (rc > iwlen)))
		return -1;

	return rc;
}

char* ConvertWCharToUtf8Alloc(const WCHAR* wstr, size_t* pUtfCharLength)
{
	char* tmp = NULL;
	const SSIZE_T rc = ConvertWCharToUtf8(wstr, NULL, 0);
	if (pUtfCharLength)
		*pUtfCharLength = 0;
	if (rc <= 0)
		return NULL;
	tmp = calloc((size_t)rc + 3ull, sizeof(char));
	if (!tmp)
		return NULL;
	const SSIZE_T rc2 = ConvertWCharToUtf8(wstr, tmp, (size_t)rc + 2ull);
	if (rc2 <= 0)
	{
		free(tmp);
		return NULL;
	}
	WINPR_ASSERT(rc == rc2);
	if (pUtfCharLength)
		*pUtfCharLength = (size_t)rc2;
	return tmp;
}

char* ConvertWCharNToUtf8Alloc(const WCHAR* wstr, size_t wlen, size_t* pUtfCharLength)
{
	char* tmp = NULL;
	const SSIZE_T rc = ConvertWCharNToUtf8(wstr, wlen, NULL, 0);

	if (pUtfCharLength)
		*pUtfCharLength = 0;
	if (rc <= 0)
		return NULL;
	tmp = calloc((size_t)rc + 3ull, sizeof(char));
	if (!tmp)
		return NULL;
	const SSIZE_T rc2 = ConvertWCharNToUtf8(wstr, wlen, tmp, (size_t)rc + 2ull);
	if (rc2 <= 0)
	{
		free(tmp);
		return NULL;
	}
	WINPR_ASSERT(rc == rc2);
	if (pUtfCharLength)
		*pUtfCharLength = (size_t)rc2;
	return tmp;
}

char* ConvertMszWCharNToUtf8Alloc(const WCHAR* wstr, size_t wlen, size_t* pUtfCharLength)
{
	char* tmp = NULL;
	const SSIZE_T rc = ConvertMszWCharNToUtf8(wstr, wlen, NULL, 0);

	if (pUtfCharLength)
		*pUtfCharLength = 0;
	if (rc <= 0)
		return NULL;
	tmp = calloc((size_t)rc + 3ull, sizeof(char));
	if (!tmp)
		return NULL;
	const SSIZE_T rc2 = ConvertMszWCharNToUtf8(wstr, wlen, tmp, (size_t)rc + 2ull);
	if (rc2 <= 0)
	{
		free(tmp);
		return NULL;
	}
	WINPR_ASSERT(rc == rc2);
	if (pUtfCharLength)
		*pUtfCharLength = (size_t)rc2;
	return tmp;
}

WCHAR* ConvertUtf8ToWCharAlloc(const char* str, size_t* pSize)
{
	WCHAR* tmp = NULL;
	const SSIZE_T rc = ConvertUtf8ToWChar(str, NULL, 0);
	if (pSize)
		*pSize = 0;
	if (rc <= 0)
		return NULL;
	tmp = calloc((size_t)rc + 3ull, sizeof(WCHAR));
	if (!tmp)
		return NULL;
	const SSIZE_T rc2 = ConvertUtf8ToWChar(str, tmp, (size_t)rc + 2ull);
	if (rc2 <= 0)
	{
		free(tmp);
		return NULL;
	}
	WINPR_ASSERT(rc == rc2);
	if (pSize)
		*pSize = (size_t)rc2;
	return tmp;
}

WCHAR* ConvertUtf8NToWCharAlloc(const char* str, size_t len, size_t* pSize)
{
	WCHAR* tmp = NULL;
	const SSIZE_T rc = ConvertUtf8NToWChar(str, len, NULL, 0);
	if (pSize)
		*pSize = 0;
	if (rc <= 0)
		return NULL;
	tmp = calloc((size_t)rc + 3ull, sizeof(WCHAR));
	if (!tmp)
		return NULL;
	const SSIZE_T rc2 = ConvertUtf8NToWChar(str, len, tmp, (size_t)rc + 2ull);
	if (rc2 <= 0)
	{
		free(tmp);
		return NULL;
	}
	WINPR_ASSERT(rc == rc2);
	if (pSize)
		*pSize = (size_t)rc2;
	return tmp;
}

WCHAR* ConvertMszUtf8NToWCharAlloc(const char* str, size_t len, size_t* pSize)
{
	WCHAR* tmp = NULL;
	const SSIZE_T rc = ConvertMszUtf8NToWChar(str, len, NULL, 0);
	if (pSize)
		*pSize = 0;
	if (rc <= 0)
		return NULL;
	tmp = calloc((size_t)rc + 3ull, sizeof(WCHAR));
	if (!tmp)
		return NULL;
	const SSIZE_T rc2 = ConvertMszUtf8NToWChar(str, len, tmp, (size_t)rc + 2ull);
	if (rc2 <= 0)
	{
		free(tmp);
		return NULL;
	}
	WINPR_ASSERT(rc == rc2);
	if (pSize)
		*pSize = (size_t)rc2;
	return tmp;
}