#!/usr/bin/env python3
"""Require PLAN/PROGRESS handoff discipline for multi-agent work."""

from __future__ import annotations

import json
import subprocess
import sys
from pathlib import Path


TRACKED_PREFIXES = (
    ".agents/",
    ".codex/",
    "AGENTS.md",
    "PLAN.md",
    "docs/",
    "phases/",
    "plugins/",
    "requirements.txt",
    "scripts/",
    "src/",
    "tests/",
)


def git_status_names(root: Path) -> list[str]:
    result = subprocess.run(
        ["git", "status", "--porcelain"],
        cwd=root,
        capture_output=True,
        text=True,
        timeout=20,
    )
    if result.returncode != 0:
        return []

    names: list[str] = []
    for line in result.stdout.splitlines():
        if not line.strip():
            continue
        path = line[3:].replace("\\", "/")
        if " -> " in path:
            path = path.split(" -> ", 1)[1]
        names.append(path)
    return names


def is_coordination_relevant(path: str) -> bool:
    return any(path == prefix or path.startswith(prefix) for prefix in TRACKED_PREFIXES)


def block(reason: str) -> int:
    json.dump({"decision": "block", "reason": reason}, sys.stdout)
    return 0


def main() -> int:
    try:
        payload = json.load(sys.stdin)
    except json.JSONDecodeError:
        return 0

    if payload.get("stop_hook_active"):
        return 0

    root = Path(payload.get("cwd") or ".").resolve()
    plan = root / "PLAN.md"
    progress = root / "PROGRESS.md"

    if not plan.exists() or not progress.exists():
        return block(
            "Multi-agent coordination requires PLAN.md and PROGRESS.md. "
            "Create or restore both files before ending the turn."
        )

    changed = git_status_names(root)
    if not changed:
        return 0

    relevant = [path for path in changed if is_coordination_relevant(path)]
    progress_changed = "PROGRESS.md" in changed

    if relevant and not progress_changed:
        return block(
            "Repository planning, docs, code, tests, requirements, or .codex files changed, "
            "but PROGRESS.md was not updated. Add a concise handoff note so the next agent "
            "can see what changed, what was verified, and what remains next."
        )

    return 0


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