from fnmatch import fnmatch

from .paths import is_excluded_path, iter_source_files

CS_SUFFIXES = frozenset({".cs"})


def is_test_file(path, config):
    return any(path.is_relative_to(root) for root in config.test_roots)


def evaluate_paths(paths, root, config):
    root = root.resolve()
    candidates = None
    for raw in paths:
        path = raw.resolve()
        if not path.is_relative_to(root):
            return f"TDD GUARD: '{path}' is outside the repository"
        if path.suffix.lower() not in CS_SUFFIXES:
            continue
        if is_excluded_path(path, root, config.exclude) or is_test_file(path, config):
            continue
        if candidates is None:
            candidates = tuple(p for p in iter_source_files(root) if p.suffix.lower() == ".cs")
        roots = (*config.test_roots, path.parent / "tests", path.parent / "test")
        names = tuple(pattern.format(stem=path.stem) for pattern in config.test_patterns)
        found = any(
            candidate.is_relative_to(test_root)
            and any(fnmatch(candidate.name if "/" not in pattern else candidate.relative_to(test_root).as_posix(), pattern)
                    for pattern in names)
            for test_root in roots for candidate in candidates
        )
        if not found:
            return (f"TDD GUARD: '{path.name}' requires an existing test such as '{names[0]}'. "
                    "Add the test in a configured test root first.")
    return None