#include <ctype.h>
#include <limits.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <wchar.h>
#include <wctype.h>

#include "floatscan.h"
#include "intscan.h"
#include "libc.h"
#include "shgetc.h"
#include "stdio_impl.h"

#define SIZE_hh -2
#define SIZE_h -1
#define SIZE_def 0
#define SIZE_l 1
#define SIZE_L 2
#define SIZE_ll 3

static void store_int(void* dest, int size, unsigned long long i) {
  if (!dest)
    return;
  switch (size) {
    case SIZE_hh:
      *(char*)dest = i;
      break;
    case SIZE_h:
      *(short*)dest = i;
      break;
    case SIZE_def:
      *(int*)dest = i;
      break;
    case SIZE_l:
      *(long*)dest = i;
      break;
    case SIZE_ll:
      *(long long*)dest = i;
      break;
  }
}

static void* arg_n(va_list ap, unsigned int n) {
  void* p;
  unsigned int i;
  va_list ap2;
  va_copy(ap2, ap);
  for (i = n; i > 1; i--)
    va_arg(ap2, void*);
  p = va_arg(ap2, void*);
  va_end(ap2);
  return p;
}

static int in_set(const wchar_t* set, int c) {
  int j;
  const wchar_t* p = set;
  if (*p == '-') {
    if (c == '-')
      return 1;
    p++;
  } else if (*p == ']') {
    if (c == ']')
      return 1;
    p++;
  }
  for (; *p && *p != ']'; p++) {
    if (*p == '-' && p[1] && p[1] != ']')
      for (j = p++ [-1]; j < *p; j++)
        if (c == j)
          return 1;
    if (c == *p)
      return 1;
  }
  return 0;
}

#if 1
#undef getwc
#define getwc(f) ((f)->rpos < (f)->rend && *(f)->rpos < 128 ? *(f)->rpos++ : (getwc)(f))

#undef ungetwc
#define ungetwc(c, f) ((f)->rend && (c) < 128U ? *--(f)->rpos : ungetwc((c), (f)))
#endif

int vfwscanf(FILE* restrict f, const wchar_t* restrict fmt, va_list ap) {
  int width;
  int size;
  int alloc;
  const wchar_t* p;
  int c = 0, t;
  char* s = NULL;
  wchar_t* wcs = NULL;
  void* dest = NULL;
  int invert;
  int matches = 0;
  off_t pos = 0, cnt;
  static const char size_pfx[][3] = {"hh", "h", "", "l", "L", "ll"};
  char tmp[3 * sizeof(int) + 10];
  const wchar_t* set;
  size_t i, k = 0u;

  FLOCK(f);

  fwide(f, 1);

  for (p = fmt; *p; p++) {
    alloc = 0;

    if (iswspace(*p)) {
      while (iswspace(p[1]))
        p++;
      while (iswspace((c = getwc(f))))
        pos++;
      ungetwc(c, f);
      continue;
    }
    if (*p != '%' || p[1] == '%') {
      p += *p == '%';
      c = getwc(f);
      if (c != *p) {
        ungetwc(c, f);
        if (c < 0)
          goto input_fail;
        goto match_fail;
      }
      pos++;
      continue;
    }

    p++;
    if (*p == '*') {
      dest = 0;
      p++;
    } else if (iswdigit(*p) && p[1] == '$') {
      dest = arg_n(ap, *p - '0');
      p += 2;
    } else {
      dest = va_arg(ap, void*);
    }

    for (width = 0; iswdigit(*p); p++) {
      width = 10 * width + *p - '0';
    }

    if (*p == 'm') {
      alloc = !!dest;
      p++;
    } else {
      alloc = 0;
    }

    size = SIZE_def;
    switch (*p++) {
      case 'h':
        if (*p == 'h')
          p++, size = SIZE_hh;
        else
          size = SIZE_h;
        break;
      case 'l':
        if (*p == 'l')
          p++, size = SIZE_ll;
        else
          size = SIZE_l;
        break;
      case 'j':
        size = SIZE_ll;
        break;
      case 'z':
      case 't':
        size = SIZE_l;
        break;
      case 'L':
        size = SIZE_L;
        break;
      case 'd':
      case 'i':
      case 'o':
      case 'u':
      case 'x':
      case 'a':
      case 'e':
      case 'f':
      case 'g':
      case 'A':
      case 'E':
      case 'F':
      case 'G':
      case 'X':
      case 's':
      case 'c':
      case '[':
      case 'S':
      case 'C':
      case 'p':
      case 'n':
        p--;
        break;
      default:
        goto fmt_fail;
    }

    t = *p;

    /* Transform S,C -> ls,lc */
    if ((t & 0x2f) == 3) {
      size = SIZE_l;
      t |= 32;
    }

    if (t != 'n') {
      if (t != '[' && (t | 32) != 'c')
        while (iswspace((c = getwc(f))))
          pos++;
      else
        c = getwc(f);
      if (c < 0)
        goto input_fail;
      ungetwc(c, f);
    }

    switch (t) {
      case 'n':
        store_int(dest, size, pos);
        /* do not increment match count, etc! */
        continue;

      case 's':
      case 'c':
      case '[':
        if (t == 'c') {
          if (width < 1)
            width = 1;
          invert = 1;
          set = L"";
        } else if (t == 's') {
          invert = 1;
          set = (const wchar_t[]){' ',    '\t',   '\n',   '\r',   11,     12,     0x0085, 0x2000,
                                  0x2001, 0x2002, 0x2003, 0x2004, 0x2005, 0x2006, 0x2008, 0x2009,
                                  0x200a, 0x2028, 0x2029, 0x205f, 0x3000, 0};
        } else {
          if (*++p == '^')
            p++, invert = 1;
          else
            invert = 0;
          set = p;
          if (*p == ']')
            p++;
          while (*p != ']') {
            if (!*p)
              goto fmt_fail;
            p++;
          }
        }

        s = (size == SIZE_def) ? dest : 0;
        wcs = (size == SIZE_l) ? dest : 0;

        int gotmatch = 0;

        if (width < 1)
          width = -1;

        i = 0;
        if (alloc) {
          k = t == 'c' ? width + 1U : 31;
          if (size == SIZE_l) {
            wcs = malloc(k * sizeof(wchar_t));
            if (!wcs)
              goto alloc_fail;
          } else {
            s = malloc(k);
            if (!s)
              goto alloc_fail;
          }
        }
        while (width) {
          if ((c = getwc(f)) < 0)
            break;
          if (in_set(set, c) == invert)
            break;
          if (wcs) {
            wcs[i++] = c;
            if (alloc && i == k) {
              k += k + 1;
              wchar_t* tmp = realloc(wcs, k * sizeof(wchar_t));
              if (!tmp)
                goto alloc_fail;
              wcs = tmp;
            }
          } else if (size != SIZE_l) {
            int l = wctomb(s ? s + i : tmp, c);
            if (l < 0)
              goto input_fail;
            i += l;
            if (alloc && i > k - 4) {
              k += k + 1;
              char* tmp = realloc(s, k);
              if (!tmp)
                goto alloc_fail;
              s = tmp;
            }
          }
          pos++;
          width -= (width > 0);
          gotmatch = 1;
        }
        if (width) {
          ungetwc(c, f);
          if (t == 'c' || !gotmatch)
            goto match_fail;
        }

        if (alloc) {
          if (size == SIZE_l)
            *(wchar_t**)dest = wcs;
          else
            *(char**)dest = s;
        }
        if (t != 'c') {
          if (wcs)
            wcs[i] = 0;
          if (s)
            s[i] = 0;
        }
        break;

      case 'd':
      case 'i':
      case 'o':
      case 'u':
      case 'x':
      case 'a':
      case 'e':
      case 'f':
      case 'g':
      case 'A':
      case 'E':
      case 'F':
      case 'G':
      case 'X':
      case 'p':
        if (width < 1)
          width = 0;
        snprintf(tmp, sizeof tmp, "%.*s%.0d%s%c%%lln", 1 + !dest, "%*", width, size_pfx[size + 2],
                 t);
        cnt = 0;
        if (fscanf(f, tmp, dest ? dest : &cnt, &cnt) == -1)
          goto input_fail;
        else if (!cnt)
          goto match_fail;
        pos += cnt;
        break;
      default:
        goto fmt_fail;
    }

    if (dest)
      matches++;
  }
  if (0) {
  fmt_fail:
  alloc_fail:
  input_fail:
    if (!matches)
      matches--;
  match_fail:
    if (alloc) {
      free(s);
      free(wcs);
    }
  }
  FUNLOCK(f);
  return matches;
}