"""Bound debug reports and reuse identical XML without breaking historical paths."""
from __future__ import annotations

import hashlib
import os
import re
import tempfile
import time
from pathlib import Path


def save_xml_snapshot(directory: Path, content: bytes, *, resource: str, tournament: str = "") -> Path:
    directory.mkdir(parents=True, exist_ok=True)
    safe_resource = re.sub(r"[^A-Za-z0-9_-]", "_", str(resource))[:64] or "resource"
    safe_tournament = re.sub(r"[^A-Za-z0-9_-]", "_", str(tournament))[:48]
    digest = hashlib.sha256(content).hexdigest()
    path = directory / f"{digest}_{safe_tournament}_{safe_resource}.xml"
    if path.is_file() and not path.is_symlink() and path.read_bytes() == content:
        return path
    temporary = None
    try:
        with tempfile.NamedTemporaryFile(dir=directory, prefix="snapshot_", suffix=".tmp", delete=False) as stream:
            temporary = Path(stream.name)
            stream.write(content)
            stream.flush()
            os.fsync(stream.fileno())
        os.replace(temporary, path)
    finally:
        if temporary is not None:
            temporary.unlink(missing_ok=True)
    return path


def trim_discovery_reports(directory: Path, *, keep: int = 40, days: int = 30) -> int:
    """Only standalone debug JSON is disposable; XML paths may be stored in PostgreSQL."""
    pattern = re.compile(r"^\d{8}_\d{6}_\d{6}_[A-Za-z0-9_-]+_games_discovery\.json$")
    reports = sorted((path for path in directory.glob("*_games_discovery.json")
                      if pattern.fullmatch(path.name) and path.is_file() and not path.is_symlink()),
                     key=lambda path: path.name, reverse=True)
    cutoff = time.time() - max(1, days) * 86400
    removed = 0
    for path in reports[max(1, keep):]:
        try:
            if path.stat().st_mtime < cutoff:
                path.unlink(missing_ok=True)
                removed += 1
        except OSError:
            # Concurrent maintenance or a read-only diagnostic directory must
            # not turn a successful data import into a failed synchronization.
            continue
    return removed