import re
import warnings
from pathlib import Path

import pytest

from logwatcher.classifier import N2_PATTERNS
from logwatcher.config import FIXTURE_PATH

ORIGINAL_LOGS_DIR = FIXTURE_PATH / "original_logs"


def _pattern_name_to_filename(name: str) -> str:
    """
        Returns the fixture corresponding to the error code name
    """
    return f"CR_{name.lower()}.txt"

def _read_fixture(path: Path) -> str:
    """
        Read a file with fallback Windows-1252.
    """
    try:
        contenu = path.read_text(encoding="utf-8")
    except UnicodeDecodeError:
        return path.read_text(encoding="windows-1252")
    if "\ufffd" not in contenu:
        return contenu
    return path.read_text(encoding="windows-1252")

@pytest.mark.parametrize("name, pattern", N2_PATTERNS.items())
def test_pattern_matches_fixture(name, pattern):
    """
        Assert each N2 pattern must match at least one line in its fixture.
    """

    fixture = ORIGINAL_LOGS_DIR / _pattern_name_to_filename(name)
    if not fixture.exists():
        msg = f"No fixture named '{fixture}'"
        warnings.warn(msg)
        pytest.skip(msg)

    lignes = [
        l for l in _read_fixture(fixture).splitlines()
        if l.strip()
    ]

    assert lignes, f"empty fixture file : {fixture}"

    match_count = 0

    for ligne in lignes:
        match = re.search(pattern, ligne)
        if match:
            match_count += 1

    assert match_count > 0, (
        f"{name} : no match in file {fixture.name}\n"
        f"pattern: {pattern}"
    )
  

def test_patterns_do_not_overlap():
    """
        Assert that a log line can match only one N2 pattern.
    """
    fixtures_dir = FIXTURE_PATH
    for fixture in fixtures_dir.glob("CR_*.txt"):
        line_list = [line for line in _read_fixture(fixture).splitlines() if line.strip()]
        for line in line_list:
            matching = [
                name for name, raw in N2_PATTERNS.items()
                if re.compile(raw).search(line)
            ]
            assert len(matching) <= 1, (
                f"Chevauchement détecté sur {fixture.name} : "
                f"{matching} match line : {line[:80]}"
            )

def test_no_orphan_fixtures():
    """
        Assert that a fixture exist only if its associated pattern exists.
        Aucun fichier de fixture ne doit exister sans pattern associé.
    """
    expected = {f"CR_{name.lower()}.txt" for name in N2_PATTERNS}
    actual = {f.name for f in FIXTURE_PATH.glob("CR_*.txt")}
    orphan = actual - expected
    assert not orphan, f"Fixtures orphelines (sans pattern) : {sorted(orphan)}"