#!/usr/bin/env python3
"""Validate only the active task's context metadata and focused pointer.

The normal path compares stat metadata first. The task-context checker is
invoked only when an input is missing, changed, or lacks the required hash.
"""

from __future__ import annotations

import argparse
import json
import subprocess
from pathlib import Path

from wbv2_runtime import ROOT, queue_pointer


def stat_metadata(path: Path) -> tuple[int, str] | None:
    try:
        value = path.stat()
    except OSError:
        return None
    return value.st_size, str(value.st_mtime_ns)


def main() -> int:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--task", help="task id; defaults to the authoritative queue pointer")
    args = parser.parse_args()
    task = args.task or queue_pointer().get("task")
    if not task:
        parser.error("queue has no current task")
    context_path = ROOT / "tests/golden" / task / "task-context.json"
    try:
        context = json.loads(context_path.read_text(encoding="utf-8"))
    except (OSError, json.JSONDecodeError):
        context = {}
    metadata = context.get("inputMetadata") if isinstance(context, dict) else None
    unchanged = isinstance(metadata, dict) and bool(metadata)
    if unchanged:
        for relative, expected in metadata.items():
            current = stat_metadata(ROOT / relative)
            if (
                not isinstance(expected, dict)
                or current is None
                or current[0] != expected.get("bytes")
                or current[1] != expected.get("mtime_ns")
                or not isinstance(expected.get("sha256"), str)
            ):
                unchanged = False
                break
    if unchanged:
        print(f"incremental-context-ok task={task} context=REUSED metadata={len(metadata)}")
        return 0
    command = ["node", "tools/web/check-task-context.mjs", "--task", task, "--write"]
    result = subprocess.run(command, cwd=ROOT, text=True, capture_output=True, check=False)
    output = result.stdout or result.stderr
    if output:
        print(output, end="" if output.endswith("\n") else "\n")
    if result.returncode:
        return result.returncode
    print(f"incremental-context-ok task={task} context=REFRESHED")
    return 0


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