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

"""Audit crate-root Rust re-export block visibility and spacing."""

from __future__ import annotations

import argparse
import pathlib
import re
import sys

from _rust_audit_common import line_depths, mask_source, selected_files

_EXPORT = re.compile(r"^(pub(?:\(crate\))?)\s+use\s+")


def audit_file(path: pathlib.Path) -> list[str]:
    """Require public re-exports before crate-public re-exports and compact blocks."""

    text = path.read_text(encoding="utf-8")
    lines = text.splitlines()
    masked, _ = mask_source(text)
    depths = line_depths(masked)
    exports: list[tuple[int, str]] = []
    for number, line in enumerate(lines, 1):
        if depths[number - 1] != 0:
            continue
        match = _EXPORT.match(line.strip())
        if match is None:
            continue
        visibility = "pub(crate)" if match.group(1) == "pub(crate)" else "pub"
        exports.append((number, visibility))

    errors: list[str] = []
    crate_seen = False
    previous_by_visibility: dict[str, int] = {}
    for number, visibility in exports:
        if visibility == "pub(crate)":
            crate_seen = True
        elif crate_seen:
            errors.append(f"{path}:{number}: pub use block must precede pub(crate) use block")
        previous = previous_by_visibility.get(visibility)
        if previous is not None:
            between = lines[previous:number - 1]
            if any(not candidate.strip() for candidate in between):
                errors.append(f"{path}:{number}: {visibility} use block contains an empty line")
        previous_by_visibility[visibility] = number

    public = [number for number, visibility in exports if visibility == "pub"]
    crate_public = [number for number, visibility in exports if visibility == "pub(crate)"]
    if public and crate_public:
        transition = lines[public[-1]:crate_public[0] - 1]
        blank_count = sum(1 for candidate in transition if not candidate.strip())
        if blank_count != 1:
            errors.append(f"{path}:{crate_public[0]}: pub use and pub(crate) use blocks require exactly one blank line; found {blank_count}")
    return errors


def main() -> int:
    """Run the read-only re-export-block audit on explicitly selected Rust files."""

    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("paths", nargs="+", help="Rust crate-root files or directories to inspect")
    args = parser.parse_args()
    files, errors = selected_files(args.paths)
    if errors or not files:
        for error in errors or ["no Rust files selected"]:
            print(f"Rust re-export-block 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 re-export-block audit: cannot read {path}: {error}", file=sys.stderr)
            return 2
    for error in errors:
        print(error, file=sys.stderr)
    if errors:
        print(f"Rust re-export-block audit: {len(errors)} error(s) across {len(files)} file(s)", file=sys.stderr)
        return 1
    print(f"Rust re-export-block audit: clean ({len(files)} file(s))")
    return 0


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