#!/usr/bin/env python3
"""Создаёт и проверяет group F5 с несколькими directory roots."""

from __future__ import annotations

import pathlib
import sys


def payload(size: int, seed: int) -> bytes:
    return bytes(((index * 41 + seed) & 0xFF) for index in range(size))


def create(root: pathlib.Path) -> None:
    source = root / "GSRC"
    target = root / "GDST"
    target.mkdir(parents=True)
    adir = source / "ADIR"
    bdir = source / "BDIR"
    (adir / "EMPTY").mkdir(parents=True)
    bdir.mkdir(parents=True)
    (adir / "A1.BIN").write_bytes(payload(10, 3))
    (bdir / "B1.TXT").write_bytes(b"second root\r\n")
    (source / "ROOT.BIN").write_bytes(payload(4097, 9))
    (source / "KEEP.TXT").write_bytes(b"not selected\r\n")


def snapshot(root: pathlib.Path) -> dict[str, bytes | None]:
    result: dict[str, bytes | None] = {}
    for path in sorted(root.rglob("*")):
        name = path.relative_to(root).as_posix().upper()
        result[name] = None if path.is_dir() else path.read_bytes()
    return result


def verify(root: pathlib.Path) -> None:
    source = root / "GSRC"
    target = root / "GDST"
    failures: list[str] = []
    expected = {
        "ADIR": None,
        "ADIR/A1.BIN": payload(10, 3),
        "ADIR/EMPTY": None,
        "BDIR": None,
        "BDIR/B1.TXT": b"second root\r\n",
        "ROOT.BIN": payload(4097, 9),
    }
    if snapshot(target) != expected:
        failures.append("target не равен двум выбранным деревьям и ROOT.BIN")
    if not (source / "KEEP.TXT").is_file():
        failures.append("source KEEP.TXT отсутствует")
    if (target / "KEEP.TXT").exists():
        failures.append("невыбранный KEEP.TXT ошибочно скопирован")
    temporary = [path.as_posix() for path in target.rglob("*")
                 if path.name.upper().endswith(".TMP")]
    if temporary:
        failures.append(f"остались temp: {temporary}")
    if failures:
        for failure in failures:
            print(f"FAIL: {failure}")
        raise SystemExit(1)
    print("PASS: selected file and two directory roots copied exactly.")


def main() -> None:
    if len(sys.argv) != 3 or sys.argv[1] not in {"create", "verify"}:
        raise SystemExit(f"usage: {sys.argv[0]} create|verify DIR")
    root = pathlib.Path(sys.argv[2])
    if sys.argv[1] == "create":
        create(root)
    else:
        verify(root)


if __name__ == "__main__":
    main()