#!/usr/bin/env python3
"""Claude SessionStart additionalContext producer for P6 observation."""

from __future__ import annotations

import hashlib
import json
import os
import sys
from pathlib import Path

BLOCK = "\n".join(
    [
        "GATE0_CLAUDE_ATOMIC_BEGIN",
        "segment-01=alpha-2d11",
        "segment-02=middle-8e22",
        "segment-03=omega-4f33",
        "GATE0_CLAUDE_ATOMIC_END",
    ]
)


def starttime(pid: int) -> int:
    text = Path(f"/proc/{pid}/stat").read_text()
    return int(text[text.rfind(")") + 2 :].split()[19])


def main() -> None:
    hook_input = json.load(sys.stdin)
    log = Path(os.environ["GATE0_CLAUDE_HOOK_LOG"])
    record = {
        "hook_event_name": hook_input.get("hook_event_name"),
        "pid": os.getpid(),
        "ppid": os.getppid(),
        "starttime_ticks": starttime(os.getpid()),
        "block_length": len(BLOCK.encode()),
        "block_sha256": hashlib.sha256(BLOCK.encode()).hexdigest(),
        "emission": "one hookSpecificOutput.additionalContext string field",
    }
    log.write_text(json.dumps(record, sort_keys=True) + "\n")
    print(
        json.dumps(
            {
                "hookSpecificOutput": {
                    "hookEventName": "SessionStart",
                    "additionalContext": BLOCK,
                }
            }
        )
    )


if __name__ == "__main__":
    main()