from __future__ import annotations

import re

import pytest

from mdpolish import Modifier, ModifierContractError, Pipeline, RunStatus, regex_replace


def test_factory_returns_modifier_and_expands_capture_groups() -> None:
    modifier = regex_replace(
        modifier_id="example.swap-date",
        version="1.0.0",
        pattern=r"(\d{4})-(\d{2})-(\d{2})",
        replacement=r"\3/\2/\1",
        applicability="处理 ISO 形状的虚构日期；不验证真实日历日期。",
    )

    result = Pipeline([modifier]).transform("A 2026-08-26, B 2027-01-02")

    assert isinstance(modifier, Modifier)
    assert result.status is RunStatus.SUCCESS
    assert result.output_markdown == "A 26/08/2026, B 02/01/2027"
    assert len(result.changes) == 2
    assert result.changes[0].before == "2026-08-26"
    assert result.changes[0].after == "26/08/2026"


def test_flags_and_factory_parameters_are_recorded() -> None:
    modifier = regex_replace(
        modifier_id="example.case",
        version="2.0.0",
        pattern="token",
        replacement="value",
        flags=re.IGNORECASE | re.MULTILINE,
    )

    result = Pipeline([modifier]).transform("TOKEN")

    assert result.status is RunStatus.SUCCESS
    assert result.modifiers[0].modifier_id == modifier.modifier_id
    assert result.modifiers[0].parameters == modifier.parameters
    assert dict(modifier.parameters) == {
        "flags": int(re.IGNORECASE | re.MULTILINE),
        "pattern": "token",
        "replacement": "value",
    }


def test_zero_match_and_no_op_replacement_are_stable() -> None:
    missing = Pipeline(
        [regex_replace(modifier_id="example.missing", version="1.0.0", pattern="missing", replacement="new")]
    ).transform("text")
    no_op = Pipeline(
        [regex_replace(modifier_id="example.no-op", version="1.0.0", pattern="text", replacement="text")]
    ).transform("text")

    assert missing.output_markdown == "text"
    assert missing.changes == ()
    assert no_op.status is RunStatus.SUCCESS
    assert no_op.changes == ()


@pytest.mark.parametrize("pattern", [r"", r"^", r"a*", r"(?=a)"])
def test_zero_length_matches_are_rejected(pattern: str) -> None:
    if pattern == r"(?=a)":
        modifier = regex_replace(
            modifier_id="example.zero",
            version="1.0.0",
            pattern=pattern,
            replacement="x",
        )
        result = Pipeline([modifier]).transform("a")
        assert result.status is RunStatus.FAILED
        assert result.partial_markdown == "a"
        assert result.changes == ()
        return

    with pytest.raises(ModifierContractError, match="zero-length"):
        regex_replace(
            modifier_id="example.zero",
            version="1.0.0",
            pattern=pattern,
            replacement="x",
        )


def test_invalid_pattern_flags_and_input_types_are_rejected() -> None:
    with pytest.raises(ModifierContractError, match="compile"):
        regex_replace(modifier_id="example.invalid", version="1.0.0", pattern="(", replacement="x")
    with pytest.raises(ModifierContractError, match="flags"):
        regex_replace(
            modifier_id="example.flags",
            version="1.0.0",
            pattern="x",
            replacement="y",
            flags=True,
        )


def test_successful_output_is_idempotent() -> None:
    pipeline = Pipeline(
        [regex_replace(modifier_id="example.space", version="1.0.0", pattern=r" {2,}", replacement=" ")]
    )
    first = pipeline.transform("a   b")
    assert first.output_markdown == "a b"
    assert first.output_markdown is not None
    assert pipeline.transform(first.output_markdown).changes == ()