#!/usr/bin/env python3
# file: scripts/audit_rust_crate_root_facades.py
# version: 1

"""Audit Rust library crate roots so `src/lib.rs` remains a facade."""

from __future__ import annotations

import argparse
import pathlib
import re
import sys

from _rust_audit_common import line_depths, mask_source

_ITEM = re.compile(
    r"^\s*(?:(?:pub(?:\([^)]*\))?)\s+)?"
    r"(?:(?:async|const|unsafe)\s+)*(?:extern\s+\"[^\"]+\"\s+)?"
    r"(?:fn|struct|enum|union|trait|impl|type|const|static|macro_rules!)\b"
)


def _selected_lib_roots(raw_paths: list[str]) -> tuple[list[pathlib.Path], list[str]]:
    roots: set[pathlib.Path] = set()
    errors: list[str] = []
    for raw_path in raw_paths:
        path = pathlib.Path(raw_path)
        if path.is_dir():
            roots.update(candidate for candidate in path.rglob("src/lib.rs") if candidate.is_file())
        elif path.is_file() and path.as_posix().endswith("src/lib.rs"):
            roots.add(path)
        else:
            errors.append(f"unsupported or missing library-root path: {path}")
    return sorted(roots), errors


def _audit_file(path: pathlib.Path) -> list[str]:
    text = path.read_text(encoding="utf-8")
    masked, _ = mask_source(text)
    lines = masked.splitlines()
    depths = line_depths(masked)
    errors: list[str] = []
    for index, line in enumerate(lines):
        if depths[index] != 0:
            continue
        if _ITEM.match(line) is not None:
            errors.append(f"{path}:{index + 1}: crate root must remain a facade; move this item to a responsibility module")
    return errors


def main() -> int:
    """Run the read-only Knowledge library crate-root facade audit."""

    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("paths", nargs="+", help="Crate roots or directories containing Rust library crates")
    arguments = parser.parse_args()
    files, errors = _selected_lib_roots(arguments.paths)
    if errors or not files:
        for error in errors or ["no Rust library crate roots selected"]:
            print(f"Rust crate-root facade audit: {error}", file=sys.stderr)
        return 2
    for path in files:
        try:
            errors.extend(_audit_file(path))
        except (OSError, UnicodeError) as error:
            print(f"Rust crate-root facade audit: cannot read {path}: {error}", file=sys.stderr)
            return 2
    for error in errors:
        print(error, file=sys.stderr)
    if errors:
        print(f"Rust crate-root facade audit: {len(errors)} error(s) across {len(files)} crate root(s)", file=sys.stderr)
        return 1
    print(f"Rust crate-root facade audit: clean ({len(files)} crate root(s))")
    return 0


if __name__ == "__main__":
    raise SystemExit(main())