#!/usr/bin/env python3
"""SessionStart hook: inject PLAN.md P0/P1 and PROGRESS.md snapshot as additionalContext."""
import json
import os
import re
import sys


def read_file(path: str) -> str:
    try:
        with open(path, encoding="utf-8") as f:
            return f.read()
    except Exception:
        return ""


def main() -> None:
    proj = os.environ.get("CLAUDE_PROJECT_DIR", ".")
    plan = read_file(os.path.join(proj, "PLAN.md"))
    progress = read_file(os.path.join(proj, "PROGRESS.md"))

    parts: list[str] = []

    # PLAN: "### P0" through (not including) "## 백로그"
    m = re.search(r"^### P0.*?(?=^## 백로그)", plan, re.M | re.S)
    if m:
        parts.append("## PLAN.md — 현재 스프린트\n\n" + m.group(0).strip())

    # PROGRESS: "## 현재 스냅샷" to EOF
    m = re.search(r"^## 현재 스냅샷.*$", progress, re.M | re.S)
    if m:
        parts.append(m.group(0).strip())

    if not parts:
        sys.exit(0)

    ctx = "\n\n".join(parts) + (
        "\n\n**에이전트 작업 시작 시 PLAN.md · PROGRESS.md를 읽는 것이 필수입니다.**"
    )

    print(
        json.dumps(
            {
                "hookSpecificOutput": {
                    "hookEventName": "SessionStart",
                    "additionalContext": ctx,
                }
            },
            ensure_ascii=False,
        )
    )

    sys.exit(0)


if __name__ == "__main__":
    try:
        main()
    except Exception as exc:
        sys.stderr.write(f"session-start-context: {exc}\n")
        sys.exit(0)