// Most of the MiniFFI class was taken from Ruby 1.8's Win32API.c,
// it's just as basic but should work fine for the moment

#include "system/fake-api.h"
#include <SDL.h>
#include <cstdint>

#include "miniffi.h"
#include "binding-util.h"

#if defined(__linux__) || defined(__APPLE__)
  #define MVAL2RB(v) ULONG2NUM(v)
  #define RB2MVAL(v) (mffi_value)NUM2ULONG(v)
#else
  #ifdef __MINGW64__
    #define MVAL2RB(v) ULL2NUM(v)
    #define RB2MVAL(v) (mffi_value)NUM2ULL(v)
  #else
    #define MVAL2RB(v) UINT2NUM(v)
    #define RB2MVAL(v) (mffi_value)NUM2UINT(v)
  #endif
#endif

#define _T_VOID 0
#define _T_NUMBER 1
#define _T_POINTER 2
#define _T_INTEGER 3
#define _T_BOOL 4

#if RAPI_FULL > 187
DEF_TYPE_CUSTOMFREE(MiniFFI, SDL_UnloadObject);
#else
DEF_ALLOCFUNC_CUSTOMFREE(MiniFFI, SDL_UnloadObject);
#endif

static void *MiniFFI_GetFunctionHandle(void *libhandle, const char *func) {
#ifdef MKXPZ_ESSENTIALS_DEBUG
#define CAPTURE(n)                                                             \
  if (!strcmp(#n, func))                                                       \
  return (void *)&MKXP_##n
  CAPTURE(GetCurrentThreadId);
  CAPTURE(GetWindowThreadProcessId);
  CAPTURE(FindWindowEx);
  CAPTURE(GetForegroundWindow);
  CAPTURE(GetClientRect);
  CAPTURE(GetCursorPos);
  CAPTURE(ScreenToClient);
  CAPTURE(SetWindowPos);
  CAPTURE(SetWindowTextA);
  CAPTURE(GetWindowRect);
  CAPTURE(GetKeyboardState);
#ifndef __WIN32__
  // Functions only needed on Linux and macOS go here
  CAPTURE(RtlMoveMemory);
  CAPTURE(LoadLibrary);
  CAPTURE(FreeLibrary);
  CAPTURE(GetAsyncKeyState);
  CAPTURE(GetSystemPowerStatus);
  CAPTURE(ShowWindow);
  CAPTURE(GetSystemMetrics);
  CAPTURE(SetCapture);
  CAPTURE(ReleaseCapture);
  CAPTURE(ShowCursor);
  CAPTURE(GetPrivateProfileString);
  CAPTURE(GetUserDefaultLangID);
  CAPTURE(GetUserName);
  CAPTURE(RegisterHotKey);
  CAPTURE(SetWindowLong);
#endif
#endif
  if (!libhandle)
    return 0;
  return SDL_LoadFunction(libhandle, func);
}

// MiniFFI.new(library, function[, imports[, exports]])
// Yields itself in blocks

RB_METHOD(MiniFFI_initialize) {
  VALUE libname, func, imports, exports;
  rb_scan_args(argc, argv, "22", &libname, &func, &imports, &exports);
  SafeStringValue(libname);
  SafeStringValue(func);
  void *hlib = SDL_LoadObject(RSTRING_PTR(libname));
  setPrivateData(self, hlib);
  void *hfunc = MiniFFI_GetFunctionHandle(hlib, RSTRING_PTR(func));
#ifdef __WIN32__
  if (hlib && !hfunc) {
    VALUE func_a = rb_str_new3(func);
    func_a = rb_str_cat(func_a, "A", 1);
    hfunc = SDL_LoadFunction(hlib, RSTRING_PTR(func_a));
  }
#endif
  if (!hfunc)
    rb_raise(rb_eRuntimeError, "%s", SDL_GetError());

  rb_iv_set(self, "_func", MVAL2RB((mffi_value)hfunc));
  rb_iv_set(self, "_funcname", func);
  rb_iv_set(self, "_libname", libname);

  VALUE ary_imports = rb_ary_new();
  VALUE *entry;
  switch (TYPE(imports)) {
  case T_NIL:
    break;
  case T_ARRAY:
    entry = RARRAY_PTR(imports);
    for (int i = 0; i < RARRAY_LEN(imports); i++) {
      SafeStringValue(entry[i]);
      switch (*(char *)RSTRING_PTR(entry[i])) {
      case 'N':
      case 'n':
      case 'L':
      case 'l':
        rb_ary_push(ary_imports, INT2FIX(_T_NUMBER));
        break;

      case 'P':
      case 'p':
        rb_ary_push(ary_imports, INT2FIX(_T_POINTER));
        break;

      case 'I':
      case 'i':
        rb_ary_push(ary_imports, INT2FIX(_T_INTEGER));
        break;

      case 'B':
      case 'b':
        rb_ary_push(ary_imports, INT2FIX(_T_BOOL));
        break;
      }
    }
    break;
  default:
    SafeStringValue(imports);
    const char *s = RSTRING_PTR(imports);
    for (int i = 0; i < RSTRING_LEN(imports); i++) {
      switch (*s++) {
      case 'N':
      case 'n':
      case 'L':
      case 'l':
        rb_ary_push(ary_imports, INT2FIX(_T_NUMBER));
        break;

      case 'P':
      case 'p':
        rb_ary_push(ary_imports, INT2FIX(_T_POINTER));
        break;

      case 'I':
      case 'i':
        rb_ary_push(ary_imports, INT2FIX(_T_INTEGER));
        break;

      case 'B':
      case 'b':
        rb_ary_push(ary_imports, INT2FIX(_T_BOOL));
        break;
      }
    }
    break;
  }

  if (MINIFFI_MAX_ARGS < RARRAY_LEN(ary_imports))
    rb_raise(rb_eRuntimeError, "too many parameters: %ld/%ld\n",
             RARRAY_LEN(ary_imports), MINIFFI_MAX_ARGS);

  rb_iv_set(self, "_imports", ary_imports);
  int ex;
  if (NIL_P(exports)) {
    ex = _T_VOID;
  } else {
    SafeStringValue(exports);
    switch (*RSTRING_PTR(exports)) {
    case 'V':
    case 'v':
      ex = _T_VOID;
      break;

    case 'N':
    case 'n':
    case 'L':
    case 'l':
      ex = _T_NUMBER;
      break;

    case 'P':
    case 'p':
      ex = _T_POINTER;
      break;

    case 'I':
    case 'i':
      ex = _T_INTEGER;
      break;

    case 'B':
    case 'b':
      ex = _T_BOOL;
      break;
    }
  }
  rb_iv_set(self, "_exports", INT2FIX(ex));
  if (rb_block_given_p())
    rb_yield(self);
  return Qnil;
}

RB_METHOD(MiniFFI_call) {
  MiniFFIFuncArgs param;
#define params param.params
  VALUE func = rb_iv_get(self, "_func");
  VALUE own_imports = rb_iv_get(self, "_imports");
  VALUE own_exports = rb_iv_get(self, "_exports");
  MINIFFI_FUNC ApiFunction = (MINIFFI_FUNC)RB2MVAL(func);
  VALUE args;
  int items = rb_scan_args(argc, argv, "0*", &args);
  int nimport = RARRAY_LEN(own_imports);
  if (items != nimport)
    rb_raise(rb_eRuntimeError,
             "wrong number of parameters: expected %d, got %d", nimport, items);

  for (int i = 0; i < nimport; i++) {
    VALUE str = rb_ary_entry(args, i);
    unsigned long lParam = 0;
    switch (FIX2INT(rb_ary_entry(own_imports, i))) {
    case _T_POINTER:
      if (NIL_P(str)) {
        lParam = 0;
      } else if (FIXNUM_P(str)) {
        lParam = RB2MVAL(str);
      } else {
        StringValue(str);
        rb_str_modify(str);
        lParam = (mffi_value)RSTRING_PTR(str);
      }
      break;

    case _T_BOOL:
      lParam = RTEST(rb_ary_entry(args, i));
      break;

    case _T_INTEGER:
#if INTPTR_MAX == INT64_MAX
      lParam = RB2MVAL(rb_ary_entry(args, i)) & UINT32_MAX;
      break;
#endif
    case _T_NUMBER:
    default:
      lParam = RB2MVAL(rb_ary_entry(args, i));
      break;
    }
    params[i] = lParam;
  }
  mffi_value ret = miniffi_call_intern(ApiFunction, &param, nimport);

  switch (FIX2INT(own_exports)) {
  case _T_NUMBER:
  case _T_INTEGER:
    return MVAL2RB(ret);

  case _T_POINTER:
    return rb_str_new_cstr((char *)ret);

  case _T_BOOL:
    return rb_bool_new(ret);

  case _T_VOID:
  default:
    return MVAL2RB(0);
  }
}

void MiniFFIBindingInit() {
  VALUE cMiniFFI = rb_define_class("MiniFFI", rb_cObject);
#if RAPI_FULL > 187
  rb_define_alloc_func(cMiniFFI, classAllocate<&MiniFFIType>);
#else
  rb_define_alloc_func(cMiniFFI, MiniFFIAllocate);
#endif
  _rb_define_method(cMiniFFI, "initialize", MiniFFI_initialize);
  _rb_define_method(cMiniFFI, "call", MiniFFI_call);
  rb_define_alias(cMiniFFI, "Call", "call");

  rb_define_const(rb_cObject, "Win32API", cMiniFFI);
}