from _winapi import *
import winfileio
import io
import os

CREATE_NEW = 1
CREATE_ALWAYS = 2
OPEN_EXISTING = 3
OPEN_ALWAYS = 4
TRUNCATE_EXISTING = 5

h = CreateFile("hello.txt", GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, 0, NULL)
with winfileio.WinFileIO(h, "w") as f:
    f.write(b"hello")
    f.write(b"world")
    x = f.tell()
    f.truncate(100);
    assert os.path.getsize("hello.txt") == 100
    y = f.tell()
    assert x == y
    f.truncate(50)
    y = f.tell()
    assert x == y
    f.seek(0, io.SEEK_END)
    f.write(b"goodbye")

h = CreateFile("hello.txt", GENERIC_READ, 0, NULL, OPEN_EXISTING, 0, NULL)
with winfileio.WinFileIO(h, "r") as f:
    assert f.tell() == 0
    print(f.read(20))
    assert f.tell() == 20
    f.seek(-15, io.SEEK_CUR)
    assert f.tell() == 5
    print(f.read(5))
    f.seek(0)
    print(f.read())
    assert f.tell() == 50 + len(b"goodbye")