#include "HalideRuntime.h"

extern "C" {

#ifdef BITS_64
#define WIN32API
#else
#define WIN32API __stdcall
#endif

typedef unsigned short WCHAR;

int WIN32API MultiByteToWideChar(
    unsigned int CodePage,
    unsigned long dwFlags,
    const char *lpMultiByteStr,
    int cbMultiByte,
    WCHAR *lpWideCharStr,
    int cchWideChar);
WIN32API void *LoadLibraryW(const WCHAR *);
WIN32API void *GetProcAddress(void *, const char *);
WIN32API unsigned SetErrorMode(unsigned);
#define SEM_FAILCRITICALERRORS 0x0001
#define SEM_NOOPENFILEERRORBOX 0x8000
#define CP_UTF8 65001

WEAK void *halide_default_get_symbol(const char *name) {
    return GetProcAddress(nullptr, name);
}

WEAK void *halide_default_load_library(const char *name) {
    // Suppress dialog windows during library open.
    unsigned old_mode = SetErrorMode(SEM_FAILCRITICALERRORS | SEM_NOOPENFILEERRORBOX);
    void *lib = nullptr;
    int wide_len = MultiByteToWideChar(CP_UTF8, 0, name, -1, nullptr, 0);
    if (wide_len > 0) {
        WCHAR *wide_lib = (WCHAR *)malloc(wide_len * sizeof(*wide_lib));
        wide_len = MultiByteToWideChar(CP_UTF8, 0, name, -1, wide_lib, wide_len);
        if (wide_len > 0) {
            lib = LoadLibraryW(wide_lib);
        }
        free(wide_lib);
    }
    SetErrorMode(old_mode);
    return lib;
}

WEAK void *halide_default_get_library_symbol(void *lib, const char *name) {
    return GetProcAddress(lib, name);
}

}  // extern "C"

namespace Halide {
namespace Runtime {
namespace Internal {

WEAK halide_get_symbol_t custom_get_symbol = halide_default_get_symbol;
WEAK halide_load_library_t custom_load_library = halide_default_load_library;
WEAK halide_get_library_symbol_t custom_get_library_symbol = halide_default_get_library_symbol;

}  // namespace Internal
}  // namespace Runtime
}  // namespace Halide

extern "C" {

WEAK halide_get_symbol_t halide_set_custom_get_symbol(halide_get_symbol_t f) {
    halide_get_symbol_t result = custom_get_symbol;
    custom_get_symbol = f;
    return result;
}

WEAK halide_load_library_t halide_set_custom_load_library(halide_load_library_t f) {
    halide_load_library_t result = custom_load_library;
    custom_load_library = f;
    return result;
}

WEAK halide_get_library_symbol_t halide_set_custom_get_library_symbol(halide_get_library_symbol_t f) {
    halide_get_library_symbol_t result = custom_get_library_symbol;
    custom_get_library_symbol = f;
    return result;
}

WEAK void *halide_get_symbol(const char *name) {
    return custom_get_symbol(name);
}

WEAK void *halide_load_library(const char *name) {
    return custom_load_library(name);
}

WEAK void *halide_get_library_symbol(void *lib, const char *name) {
    return custom_get_library_symbol(lib, name);
}

}  // extern "C"