"""Installation code (install_code) for the Windows installer EXE flow.

Covers central/app/enrollment.py install-code functions: Crockford Base32
generation, normalization (case + hyphen), hashing, and the grouped display
format. Never stores the plaintext code.
"""
import re

import pytest

from central.app import enrollment


def test_generated_code_is_16_crockford_chars_in_4_groups():
    for _ in range(50):
        code = enrollment.generate_install_code()
        assert re.fullmatch(r"[0-9A-HJKMNP-TV-Z]{4}-[0-9A-HJKMNP-TV-Z]{4}-[0-9A-HJKMNP-TV-Z]{4}-[0-9A-HJKMNP-TV-Z]{4}", code)


def test_generated_code_has_good_entropy():
    seen = {enrollment.generate_install_code() for _ in range(2000)}
    assert len(seen) > 1900  # 80 bits of entropy: collisions essentially impossible


def test_crockford_alphabet_excludes_ambiguous_chars():
    alphabet = set(enrollment.INSTALL_CODE_ALPHABET)
    for ambiguous in "ILOU":
        assert ambiguous not in alphabet


def test_normalization_uppercases_and_strips_separators():
    assert enrollment.normalize_install_code("abcd-efgh-jkmn-pqrz") == "ABCDEFGHJKMNPQRZ"
    assert enrollment.normalize_install_code(" abcd efgh jkmn pqrz ") == "ABCDEFGHJKMNPQRZ"
    assert enrollment.normalize_install_code("ABCD-EFGH-JKMN-PQRZ") == "ABCDEFGHJKMNPQRZ"


def test_normalization_maps_crockford_lookalikes():
    # Crockford Base32 treats 0/O and 1/I/L as transliterations; a human
    # retyping "O" and "I/L" means "0" and "1".
    assert enrollment.normalize_install_code("OOOI-LLLL-0000-0001") == "0001111100000001"
    assert enrollment.normalize_install_code("0O0O-1L1I-0000-0001") == enrollment.normalize_install_code("0000-1111-0000-0001")


def test_digest_is_sha256_hex_and_deterministic():
    code = enrollment.generate_install_code()
    normalized = enrollment.normalize_install_code(code)
    assert enrollment.install_code_digest(code) == enrollment.install_code_digest(normalized)
    assert enrollment.install_code_digest(code) == enrollment.install_code_digest(code.lower().replace("-", ""))
    assert len(enrollment.install_code_digest(code)) == 64


def test_hashes_cannot_be_reversed_into_plaintext():
    code = enrollment.generate_install_code()
    digest = enrollment.install_code_digest(code)
    assert digest != code
    assert code not in digest


def test_valid_install_code():
    code = enrollment.generate_install_code()
    assert enrollment.valid_install_code(code)
    assert enrollment.valid_install_code(code.lower().replace("-", ""))
    assert not enrollment.valid_install_code("")
    assert not enrollment.valid_install_code("ABCD-EFGH-JKMN-PQRU")  # U excluded from Crockford
    assert not enrollment.valid_install_code("ABCD")
    assert not enrollment.valid_install_code("!BCD-EFGH-JKMN-PQRZ")