# Copyright (c) 2026 Krzysztof Rudnicki. MIT licence.
"""Folding a typed command down to a comparable skeleton.

Every non-ASCII literal here is an escape. These tests exist because two
characters looked identical, so a reader must be able to see which codepoint
each case actually means.
"""

from __future__ import annotations

import pytest

from signal_bot.folding import TABLE, fold

# The regression itself: `!gecko` as it arrives from a Russian keyboard, with
# U+0435 for the `e` and U+043E for the `o`.
RUSSIAN_GECKO = "!g\u0435ck\u043e"


def test_the_cyrillic_gecko_that_started_this() -> None:
    assert fold(RUSSIAN_GECKO) == "!gecko"
    assert RUSSIAN_GECKO != "!gecko"


@pytest.mark.parametrize(
    ("typed", "expected"),
    [
        # Cyrillic
        ("!\u043a\u043e\u0442", "!kot"),
        ("!\u0441\u0430\u0442", "!cat"),
        ("!d\u043eg", "!dog"),
        # Greek
        ("!d\u03bfg", "!dog"),
        ("!\u03bau\u03bf\u03c4", "!kuot"),
        # Latin small capitals
        ("!\u1d0b\u1d0f\u1d1b", "!kot"),
        # Latin letters that are not ASCII
        ("!d\u00f8g", "!dog"),
        ("!p\u0131es", "!pies"),
        # Leetspeak
        ("!g3ck0", "!gecko"),
        ("!d0g", "!dog"),
        ("!c4t", "!cat"),
        ("!p13s", "!pies"),
        ("!5zczek", "!szczek"),
        ("!ca7", "!cat"),
        # Compatibility forms NFKC already handles
        ("!\uff44\uff4f\uff47", "!dog"),
        ("!\U0001d5f8\U0001d5fc\U0001d601", "!kot"),
        # Diacritics decompose away
        ("!papie\u017c", "!papiez"),
        ("!k\u00f3t", "!kot"),
        # Invisible characters are dropped
        ("!d\u200bog", "!dog"),
        ("!d\u200dog", "!dog"),
        ("!dog\u00ad", "!dog"),
        ("!\ufeffdog", "!dog"),
        # Case and surrounding whitespace
        ("  !DOG  ", "!dog"),
        ("!Dog", "!dog"),
        (" !dog ", "!dog"),
    ],
)
def test_fold_maps_lookalikes_onto_ascii(typed: str, expected: str) -> None:
    assert fold(typed) == expected


def test_fold_keeps_internal_whitespace() -> None:
    """Argument support (0.0.6) splits on it, so folding must not eat it."""
    assert fold("!suggest !gecko co ma robic") == "!suggest !gecko co ma robic"


def test_fold_leaves_ordinary_text_alone() -> None:
    assert fold("!dog") == "!dog"
    assert fold("hello there") == "hello there"
    assert fold("") == ""


def test_fold_is_idempotent() -> None:
    """Folding twice must equal folding once, or triggers drift from input."""
    for typed in (RUSSIAN_GECKO, "!g3ck0", "!\u1d0b\u1d0f\u1d1b", "!papie\u017c"):
        assert fold(fold(typed)) == fold(typed)


def test_fold_does_not_collapse_genuinely_different_commands() -> None:
    """The table must not be so eager that distinct commands become one."""
    assert fold("!cat") != fold("!dog")
    assert fold("!kot") != fold("!kots")
    assert fold("!gekon") != fold("!geko")


def test_every_mapping_target_is_ascii() -> None:
    """A mapping onto another non-ASCII character would need folding again."""
    for replacement in TABLE.values():
        assert replacement.isascii()


def test_table_covers_both_alphabets_that_bit_us() -> None:
    assert TABLE[0x043E] == "o"
    assert TABLE[0x0435] == "e"
    assert TABLE[0x03BF] == "o"