#include <windows.h>

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

#include <utils.h>

void utils_map_file(const wchar_t *path, struct file_mapping *map) {
    map->file = CreateFileW(path, FILE_READ_ACCESS, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
    if (map->file == INVALID_HANDLE_VALUE) {
        msg_err_w(L"Could not open file: %ls", path);
    }

    map->mapping = CreateFileMappingA(map->file, NULL, PAGE_READONLY, 0, 0, NULL);
    map->data = MapViewOfFile(map->mapping, FILE_MAP_READ, 0, 0, 0);
    if (!map->data) {
        msg_err_w(L"Could not map view of file %ls", path);
    }
}

void utils_unmap_file(struct file_mapping *map)  {
    UnmapViewOfFile(map->data);
    CloseHandle(map->mapping);
    CloseHandle(map->file);
}

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

uint32_t utils_file_crc32c(const wchar_t *filePath) {
    struct file_mapping map;
    utils_map_file(filePath, &map);

    LARGE_INTEGER fileSize;
    GetFileSizeEx(map.file, &fileSize);

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

    utils_unmap_file(&map);
    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 == INVALID_HANDLE_VALUE) {
        msg_err_w(L"Could not create 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, const void *buf, size_t size) {
    DWORD oldProtect;
    VirtualProtect(addr, size, PAGE_READWRITE, &oldProtect);

    memcpy(addr, buf, size);

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