"""
Session mirroring for cross-platform message delivery.

When a message is sent to a platform (via send_message or cron delivery),
this module appends a "delivery-mirror" record to the target session's
transcript so the receiving-side agent has context about what was sent.

Standalone -- works from CLI, cron, and gateway contexts without needing
the full SessionStore machinery.
"""

import json
import logging
from datetime import datetime
from pathlib import Path
from typing import Optional

logger = logging.getLogger(__name__)

_SESSIONS_DIR = Path.home() / ".hermes" / "sessions"
_SESSIONS_INDEX = _SESSIONS_DIR / "sessions.json"


def mirror_to_session(
    platform: str,
    chat_id: str,
    message_text: str,
    source_label: str = "cli",
) -> bool:
    """
    Append a delivery-mirror message to the target session's transcript.

    Finds the gateway session that matches the given platform + chat_id,
    then writes a mirror entry to both the JSONL transcript and SQLite DB.

    Returns True if mirrored successfully, False if no matching session or error.
    All errors are caught -- this is never fatal.
    """
    try:
        session_id = _find_session_id(platform, str(chat_id))
        if not session_id:
            logger.debug("Mirror: no session found for %s:%s", platform, chat_id)
            return False

        mirror_msg = {
            "role": "assistant",
            "content": message_text,
            "timestamp": datetime.now().isoformat(),
            "mirror": True,
            "mirror_source": source_label,
        }

        _append_to_jsonl(session_id, mirror_msg)
        _append_to_sqlite(session_id, mirror_msg)

        logger.debug("Mirror: wrote to session %s (from %s)", session_id, source_label)
        return True

    except Exception as e:
        logger.debug("Mirror failed for %s:%s: %s", platform, chat_id, e)
        return False


def _find_session_id(platform: str, chat_id: str) -> Optional[str]:
    """
    Find the active session_id for a platform + chat_id pair.

    Scans sessions.json entries and matches where origin.chat_id == chat_id
    on the right platform.  DM session keys don't embed the chat_id
    (e.g. "agent:main:telegram:dm"), so we check the origin dict.
    """
    if not _SESSIONS_INDEX.exists():
        return None

    try:
        with open(_SESSIONS_INDEX, encoding="utf-8") as f:
            data = json.load(f)
    except Exception:
        return None

    platform_lower = platform.lower()
    best_match = None
    best_updated = ""

    for _key, entry in data.items():
        origin = entry.get("origin") or {}
        entry_platform = (origin.get("platform") or entry.get("platform", "")).lower()

        if entry_platform != platform_lower:
            continue

        origin_chat_id = str(origin.get("chat_id", ""))
        if origin_chat_id == str(chat_id):
            updated = entry.get("updated_at", "")
            if updated > best_updated:
                best_updated = updated
                best_match = entry.get("session_id")

    return best_match


def _append_to_jsonl(session_id: str, message: dict) -> None:
    """Append a message to the JSONL transcript file."""
    transcript_path = _SESSIONS_DIR / f"{session_id}.jsonl"
    try:
        with open(transcript_path, "a", encoding="utf-8") as f:
            f.write(json.dumps(message, ensure_ascii=False) + "\n")
    except Exception as e:
        logger.debug("Mirror JSONL write failed: %s", e)


def _append_to_sqlite(session_id: str, message: dict) -> None:
    """Append a message to the SQLite session database."""
    db = None
    try:
        from hermes_state import SessionDB
        db = SessionDB()
        db.append_message(
            session_id=session_id,
            role=message.get("role", "assistant"),
            content=message.get("content"),
        )
    except Exception as e:
        logger.debug("Mirror SQLite write failed: %s", e)
    finally:
        if db is not None:
            db.close()