/*
    polyfill: mingw32 polyfills for missing C/POSIX functions
    Written by Giovanni Bajo <giovannibajo@gmail.com>

    This tool is part of the Libdragon SDK.

    This is free and unencumbered software released into the public domain.

    For more information, please refer to <http://unlicense.org/>
*/
#ifndef LIBDRAGON_TOOLS_POLYFILL_H
#define LIBDRAGON_TOOLS_POLYFILL_H

#ifdef __MINGW32__

// NOTE: we include both stdio.h and cstdio because both of them will undef
// tmpfile and redefine it to something else. Since we want to provide our
// own implementation, we need to make sure both are included first, so that
// we don't run the risk either of them is included after this file.
#include <stdio.h>
#ifdef __cplusplus
#include <cstdio>
#endif
// NOTE: include both assert.h and cassert because we need to make sure
// _assert and _wassert are declared properly before we mess with them later.
#include <assert.h>
#ifdef __cplusplus
#include <cassert>
#endif
#include <stdlib.h>
#include <errno.h>
#include <stdint.h>
#include <stdbool.h>
#include <string.h>
#include <process.h>
#include <share.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <time.h>

#ifdef __cplusplus
extern "C" {
#endif
 
 // if typedef doesn't exist (msvc, blah)
 typedef intptr_t ssize_t;
 
 /* Implementation of 'getline' fetched from: https://stackoverflow.com/a/47229318 */
 /* The original code is public domain -- Will Hartung 4/9/09 */
 /* Modifications, public domain as well, by Antti Haapala, 11/10/17
    - Switched to getc on 5/23/19 */
 __attribute__((used))
  static ssize_t getline(char **lineptr, size_t *n, FILE *stream) {
  size_t pos;
  int c;
  
  if (lineptr == NULL || stream == NULL || n == NULL) {
   errno = EINVAL;
   return -1;
  }
  
  c = getc(stream);
  if (c == EOF) {
   return -1;
  }
  
  if (*lineptr == NULL) {
   *lineptr = (char*)malloc(128);
   if (*lineptr == NULL) {
    return -1;
   }
   *n = 128;
  }
  
  pos = 0;
  while(c != EOF) {
   if (pos + 1 >= *n) {
    size_t new_size = *n + (*n >> 2);
    if (new_size < 128) {
     new_size = 128;
    }
    char *new_ptr = (char*)realloc(*lineptr, new_size);
    if (new_ptr == NULL) {
     return -1;
    }
    *n = new_size;
    *lineptr = new_ptr;
   }
   
   ((unsigned char *)(*lineptr))[pos ++] = c;
   if (c == '\n') {
    break;
   }
   c = getc(stream);
  }
  
  (*lineptr)[pos] = '\0';
  return pos;
 }
 
 // Provide implementation of strndup for MSYS2 environments that are missing it (before April 13 2026).
#if defined(MSYS2_RUNTIME_PACMAN_AGE) && MSYS2_RUNTIME_PACMAN_AGE <= 20260413
 __attribute__((used))
  static char *msys2_fallback_strndup(const char *s, size_t n)
 {
  size_t len = strnlen(s, n);
  char *ret = (char*)malloc(len + 1);
  if (!ret) return NULL;
  memcpy(ret, s, len);
  ret[len] = '\0';
  return ret;
 }
 
#ifdef strndup
#undef strndup
#endif
#define strndup   msys2_fallback_strndup
#endif
 
 // Replace 'assert' so that it has 'noreturn' behaviour on Windows.
 // (soft reverts this MSYS2 commit: https://sourceforge.net/p/mingw-w64/mingw-w64/ci/ecf2328a328d11dec7044b40b2b5e93b5b2b9d9e/)
#if defined(MSYS2_RUNTIME_PACMAN_AGE) && MSYS2_RUNTIME_PACMAN_AGE >= 20260611 && !defined(NDEBUG)
 
#if defined(_UNICODE) || defined(UNICODE)
 
 __attribute__((used)) __attribute__((noreturn))
  static void msys2_wassert_fix(const wchar_t* _Message, const wchar_t* _File, unsigned _Line)
 {
  _wassert(_Message, _File, _Line);
  abort();
  __builtin_unreachable();
 }
 
#define _wassert(a,b,c) msys2_wassert_fix(a,b,c)
 
#else
 
 __attribute__((used)) __attribute__((noreturn))
  static void msys2_assert_fix(const char* _Message, const char* _File, unsigned _Line)
 {
  _assert(_Message, _File, _Line);
  abort();
  __builtin_unreachable();
 }
 
#define _assert(a,b,c) msys2_assert_fix(a,b,c)
 
#endif // defined(_UNICODE) || defined(UNICODE)
 
#endif
 
#if defined(__MSVCRT_VERSION__) && __MSVCRT_VERSION__ >= 0xE00
 // UCRT is being used so we can use runtime-provided tmpfile() implementation
#else
 // tmpfile() in MINGW64 is broken for use (it uses MSVCRT that tries to
 // create a file in C:\, which is non-writable nowadays)
#ifdef tmpfile
#undef tmpfile
#endif
#define tmpfile()   mingw_tmpfile()
#endif
 
 typedef void* HANDLE;
 typedef const char* LPCSTR;
 typedef int BOOL;
#define INVALID_HANDLE_VALUE ((HANDLE)(long)-1)
 struct _SECURITY_ATTRIBUTES;
 
 // Access rights
#define GENERIC_READ        0x80000000
#define GENERIC_WRITE       0x40000000
 
 // Share modes
#define FILE_SHARE_READ     0x00000001
#define FILE_SHARE_WRITE    0x00000002
#define FILE_SHARE_DELETE   0x00000004
 
 // Creation disposition
#define CREATE_NEW          1
 
 // Flags and attributes
#define FILE_ATTRIBUTE_TEMPORARY     0x00000100
#define FILE_FLAG_DELETE_ON_CLOSE    0x04000000
 
 __declspec(dllimport) HANDLE __stdcall CreateFileA(
                                                    LPCSTR lpFileName,
                                                    unsigned long dwDesiredAccess,
                                                    unsigned long dwShareMode,
                                                    struct _SECURITY_ATTRIBUTES* lpSecurityAttributes,
                                                    unsigned long dwCreationDisposition,
                                                    unsigned long dwFlagsAndAttributes,
                                                    HANDLE hTemplateFile
                                                    );
 __declspec(dllimport) int __stdcall CloseHandle(HANDLE);
 __declspec(dllimport) unsigned long __stdcall GetLastError(void);
 __declspec(dllimport) unsigned long __stdcall GetTickCount(void);
 
 __attribute__((used))
  static FILE *mingw_tmpfile(void) {
  static int counter = 0;
  char path[260];
  
  for (int i = 0; i < 4096; i++) {
   // Generate a random filename. Notice we *purposedly* not make this
   // very random with PID, timestamp, etc. because this is the third
   // iteration of mingw_tmpfile(): the previous ones were misbehaving
   // in various ways on various CRTs, Windows versions, etc. 
   // We want this code to be exercised often so that it is robust.
   snprintf(path, sizeof(path), "mksprite-%04x.tmp", counter++);
   
   HANDLE h = CreateFileA(
                          path,
                          GENERIC_READ | GENERIC_WRITE,
                          FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
                          NULL,
                          CREATE_NEW,
                          FILE_ATTRIBUTE_TEMPORARY | FILE_FLAG_DELETE_ON_CLOSE,
                          NULL
                          );
   
   if (h != INVALID_HANDLE_VALUE) {
    int fd = _open_osfhandle((intptr_t)h, _O_RDWR | _O_BINARY);
    if (fd == -1) {
     CloseHandle(h);
     return NULL;
    }
    return fdopen(fd, "w+b");
   }
   
   // 80 = ERROR_FILE_EXISTS
   if (GetLastError() != 80)
    break;
  }
  
  return NULL;
 }
 
 __attribute__((used))
  static char* strcasestr(const char* haystack, const char* needle)
 {
  size_t needle_len = strlen(needle);
  size_t haystack_len = strlen(haystack);
  size_t i;
  
  if (needle_len > haystack_len)
   return NULL;
  
  for (i = 0; i <= haystack_len - needle_len; i++)
  {
   if (strncasecmp(haystack + i, needle, needle_len) == 0)
    return (char*)(haystack + i);
  }
  
  return NULL;
 }
 
 // Implementation from FreeBSD
 __attribute__((used))
  static void *memmem(const void *l, size_t l_len, const void *s, size_t s_len)
 {
  char *cur, *last;
  const char *cl = (const char *)l;
  const char *cs = (const char *)s;
  
  /* we need something to compare */
  if (l_len == 0 || s_len == 0)
   return NULL;
  
  /* "s" must be smaller or equal to "l" */
  if (l_len < s_len)
   return NULL;
  
  /* special case where s_len == 1 */
  if (s_len == 1)
   return memchr(l, (int)*cs, l_len);
  
  /* the last position where its possible to find "s" in "l" */
  last = (char *)cl + l_len - s_len;
  
  for (cur = (char *)cl; cur <= last; cur++)
   if (cur[0] == cs[0] && memcmp(cur, cs, s_len) == 0)
			return cur;
  
  return NULL;
 }
 
 // rename() that ovewrites the destination file
#define rename(a,b)  mingw_rename(a,b)
 
#define MOVEFILE_REPLACE_EXISTING 0x00000001
#define MOVEFILE_WRITE_THROUGH    0x00000008
 
 __declspec(dllimport) int __stdcall MoveFileExA(const char *lpExistingFileName,
                                                 const char *lpNewFileName,
                                                 unsigned long dwFlags);
 __declspec(dllimport) unsigned long __stdcall GetLastError(void);
 
 static void map_windows_error_to_errno(unsigned long err) {
  switch (err) {
   case 2:    errno = ENOENT; break;        // ERROR_FILE_NOT_FOUND
   case 3:    errno = ENOENT; break;        // ERROR_PATH_NOT_FOUND
   case 5:    errno = EACCES; break;        // ERROR_ACCESS_DENIED
   case 32:   errno = EBUSY; break;         // ERROR_SHARING_VIOLATION
   case 80:   errno = EEXIST; break;        // ERROR_FILE_EXISTS
   case 183:  errno = EEXIST; break;        // ERROR_ALREADY_EXISTS
   default:   errno = EIO; break;           // Generic error
  }
 }
 
 __attribute__((used))
  static int mingw_rename(const char *oldpath, const char *newpath) {
  if (MoveFileExA(oldpath, newpath, MOVEFILE_REPLACE_EXISTING | MOVEFILE_WRITE_THROUGH)) {
   return 0;
  } else {
   map_windows_error_to_errno(GetLastError());
   return -1;
  }
 }
 
 // POISX mkdir has a mode argument, but mingw's mkdir doesn't
#define mkdir(path, mode) mkdir(path)
 
 typedef struct _PROCESS_BASIC_INFORMATION_MIN {
  void* Reserved1;
  void* PebBaseAddress;
  void* Reserved2[2];
  void* UniqueProcessId;
  void* InheritedFromUniqueProcessId;
 } PROCESS_BASIC_INFORMATION_MIN;
 
#define CURRENT_PROCESS ((HANDLE)(intptr_t)-1)
 
 __declspec(dllimport) long __stdcall NtQueryInformationProcess(
                                                                HANDLE ProcessHandle, unsigned long ProcessInformationClass,
                                                                void* ProcessInformation, unsigned long ProcessInformationLength,
                                                                unsigned long *ReturnLength);
 
 // Enable long path support in the current process.
 // This is a hacky workaround for a limitation in Windows where
 // file paths longer than 260 characters are not supported.
 // The documented ways involve also setting a registry key, and thus
 // is not suitable for a tool like this.
 // This same approach is used by the Go runtime on Windows, so it is
 // reasonably safe to use it here as well.
 __attribute__((used))
  static void enable_peb_long_path_unsafe(void)
 {
  PROCESS_BASIC_INFORMATION_MIN pbi; unsigned long retlen;
  if (NtQueryInformationProcess(CURRENT_PROCESS, 0, &pbi, sizeof(pbi), &retlen) < 0)
   return;
  volatile uint8_t *peb = (volatile uint8_t*)pbi.PebBaseAddress;
  enum { PEB_BITFIELD_OFFSET = 3, IS_LONG_PATH_AWARE_MASK = 0x80 };
  peb[PEB_BITFIELD_OFFSET] |= (uint8_t)IS_LONG_PATH_AWARE_MASK;
 }
 
 // If it was defined, undefine it as there's no limit on path length after the hack above
#undef MAX_PATH
 
 __declspec(dllimport) int __stdcall SetConsoleOutputCP(unsigned int);
 __declspec(dllimport) int __stdcall SetConsoleCP(unsigned int);
 __declspec(dllimport) unsigned int __stdcall GetConsoleOutputCP(void);
 __declspec(dllimport) unsigned int __stdcall GetConsoleCP(void);
#define CP_UTF8 65001
 
 static int old_out_cp = 0;
 static int old_in_cp = 0;
 
 __attribute__((used))
  static void winconsole_restore(void) {
  if (old_out_cp)
   SetConsoleOutputCP(old_out_cp);
  if (old_in_cp)
   SetConsoleCP(old_in_cp);
 }
 
 __attribute__((used))
  static void winconsole_utf8(void) {
  // Enable long path support in the current process
  enable_peb_long_path_unsafe();
  
  // Save the current code page
  old_out_cp = GetConsoleOutputCP();
  old_in_cp = GetConsoleCP();
  
  // Enable UTF-8 in the console
  SetConsoleOutputCP(CP_UTF8);
  SetConsoleCP(CP_UTF8);
  
  atexit(winconsole_restore);
 }
 
#ifdef __cplusplus
}
#endif


#else /* __MINGW32__ */

#ifdef __cplusplus
extern "C" {
#endif
 
 __attribute__((used))
  static void winconsole_utf8(void) {}
 
#ifdef __cplusplus
}
#endif

#endif /* __MINGW32__ */

#endif