#include <windows.h>

#include <crc32.h>
#include <msg.h>

#include <utils.h>

int utils_path_exists(const wchar_t *filePath) {
    return GetFileAttributesW(filePath) != INVALID_FILE_ATTRIBUTES;
}

uint32_t utils_file_crc32c(const wchar_t *filePath) {
    HANDLE file = CreateFileW(filePath, FILE_READ_ACCESS, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
    if (!file) {
        msg_err_w(L"Could not open file: %ls", filePath);
    }

    LARGE_INTEGER fileSize;
    GetFileSizeEx(file, &fileSize);

    HANDLE hMap = CreateFileMappingA(file, NULL, PAGE_READONLY, 0, 0, NULL);
    char *map = MapViewOfFile(hMap, FILE_MAP_READ, 0, 0, 0);
    if (!map) {
        msg_err_w(L"Could not create file mapping for %ls", filePath);
    }

    uint32_t crc = crc32c(0, map, fileSize.QuadPart);

    UnmapViewOfFile(map);
    CloseHandle(hMap);
    CloseHandle(file);

    return crc;
}

// https://stackoverflow.com/a/16719260
void utils_create_parent_dirs(const wchar_t *path) {
    wchar_t dir[MAX_PATH];
    ZeroMemory(dir, sizeof(dir));

    const wchar_t *end = path - 1;

    while((end = wcschr(++end, L'\\')) != NULL) {
        wcsncpy(dir, path, end - path + 1);

        if (!utils_path_exists(dir) && !CreateDirectoryW(dir, NULL)) {
            msg_err_w(L"Failed to create directory: %ls", dir);
        }
    }
}

void utils_save_to_file(const wchar_t *filePath, const void *buf, size_t length) {
    HANDLE file = CreateFileW(filePath, FILE_WRITE_ACCESS, FILE_SHARE_READ, NULL, CREATE_NEW, FILE_ATTRIBUTE_NORMAL, NULL);
    if (!file) {
        msg_err_w(L"Could not open file: %ls", filePath);
    }

    WriteFile(file, buf, length, NULL, FALSE);

    CloseHandle(file);
}

char utils_env_enabled(const char *env) {
    char *envText = getenv(env);
    return envText && *envText;
}

void utils_write_protected_memory(void *addr, void *buf, size_t size) {
    DWORD oldProtect;
    VirtualProtect(addr, size, PAGE_READWRITE, &oldProtect);

    memcpy(addr, buf, size);
    
    VirtualProtect(addr, size, oldProtect, &oldProtect);
}