import json
from datetime import datetime, timezone
from pathlib import Path

DEFAULT_BASE_DIR = "~/.timmy/training-data/evennia"


def telemetry_dir(base_dir: str | Path = DEFAULT_BASE_DIR) -> Path:
    return Path(base_dir).expanduser()


def _session_day() -> str:
    return datetime.now(timezone.utc).strftime("%Y%m%d")


def event_log_path(session_id: str, base_dir: str | Path = DEFAULT_BASE_DIR) -> Path:
    session_id = (session_id or "unbound").strip() or "unbound"
    return telemetry_dir(base_dir) / _session_day() / f"{session_id}.jsonl"


def session_meta_path(session_id: str, base_dir: str | Path = DEFAULT_BASE_DIR) -> Path:
    session_id = (session_id or "unbound").strip() or "unbound"
    return telemetry_dir(base_dir) / _session_day() / f"{session_id}.meta.json"


def write_session_metadata(session_id: str, metadata: dict, base_dir: str | Path = DEFAULT_BASE_DIR) -> Path:
    path = session_meta_path(session_id, base_dir)
    path.parent.mkdir(parents=True, exist_ok=True)
    payload = {}
    if path.exists():
        try:
            payload = json.loads(path.read_text(encoding="utf-8"))
        except Exception:
            payload = {}
    payload.update(metadata or {})
    payload.setdefault("session_id", session_id)
    payload.setdefault("event_log_path", str(event_log_path(session_id, base_dir)))
    payload.setdefault("updated_at", datetime.now(timezone.utc).isoformat())
    path.write_text(json.dumps(payload, indent=2, ensure_ascii=False), encoding="utf-8")
    return path


def append_event(session_id: str, event: dict, base_dir: str | Path = DEFAULT_BASE_DIR) -> Path:
    path = event_log_path(session_id, base_dir)
    path.parent.mkdir(parents=True, exist_ok=True)
    payload = dict(event)
    payload.setdefault("timestamp", datetime.now(timezone.utc).isoformat())
    with path.open("a", encoding="utf-8") as f:
        f.write(json.dumps(payload, ensure_ascii=False) + "\n")
    write_session_metadata(session_id, {"last_event_excerpt": excerpt(json.dumps(payload, ensure_ascii=False), 400)}, base_dir)
    return path


def excerpt(text: str, limit: int = 240) -> str:
    text = " ".join((text or "").split())
    return text if len(text) <= limit else text[: limit - 3] + "..."