#!/usr/bin/env python3
"""Select the dedicated issue-triage check for an isolated triage tree change.

These inputs run only in the issue-event workflow, not the Pulse application.
Their locked parser and silent-mutation tests still run on the proposed source,
as do the independent secret scan and governance. Mixed, empty or unavailable
diffs retain the ordinary application checks. Changes to this selector or its
workflow/tests cannot opt themselves out of those checks.
"""

import argparse
import re
import subprocess
import sys


COMMIT = re.compile(r"[0-9a-f]{40}")
TRIAGE_INPUTS = frozenset({
    b".github/scripts/issue-version-triage.cjs",
    b".github/scripts/issue-version-triage.test.cjs",
    b".github/scripts/triage-comment-policy.test.cjs",
    b".github/scripts/package.json",
    b".github/scripts/package-lock.json",
    b"docs/ISSUE_TRIAGE.md",
})


def triage_only_paths(paths):
    return bool(paths) and all(path in TRIAGE_INPUTS for path in paths)


def triage_only_diff(base, head):
    if not COMMIT.fullmatch(base) or not COMMIT.fullmatch(head):
        return False
    try:
        # Inspect the entire range, including deleted names. Neither a rename
        # into this allowlist nor Git's quoted display of a filename may hide
        # a product change. A missing/truncated diff always keeps runtime CI.
        result = subprocess.run(
            ["git", "diff", "--no-ext-diff", "--no-renames", "--name-only", "-z",
             base, head, "--"],
            capture_output=True, timeout=30, check=False,
        )
    except (OSError, subprocess.TimeoutExpired):
        print("Triage tree diff unavailable; retaining application CI.", file=sys.stderr)
        return False
    if result.returncode != 0 or not result.stdout.endswith(b"\0"):
        return False
    return triage_only_paths(result.stdout[:-1].split(b"\0"))


def main():
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--base", required=True)
    parser.add_argument("--head", required=True)
    args = parser.parse_args()
    print("true" if triage_only_diff(args.base, args.head) else "false")


if __name__ == "__main__":
    main()