#!/usr/bin/env python3
"""
Matrix Helper Utilities

Shared utilities for Matrix client operations, reducing code duplication
across matrix_mcp.py and matrix_integration.py.
"""

import json
import logging
from contextlib import asynccontextmanager
from pathlib import Path
from typing import AsyncIterator

try:
    from nio import AsyncClient
except ImportError:
    raise ImportError(
        "matrix-nio not installed. Install with: pip3 install matrix-nio\n"
        "Note: Without [e2e] extra, only unencrypted rooms are supported"
    )

# Configuration
CREDENTIALS_FILE = Path.home() / ".matrix-credentials.json"
MATRIX_DATA_DIR = Path.home() / ".matrix-data"

logger = logging.getLogger(__name__)


def load_credentials() -> dict:
    """Load Matrix credentials from JSON file"""
    if not CREDENTIALS_FILE.exists():
        raise FileNotFoundError(
            f"Credentials file not found: {CREDENTIALS_FILE}\n"
            f"Run setup_matrix.sh to create credentials"
        )

    try:
        with open(CREDENTIALS_FILE, 'r') as f:
            return json.load(f)
    except Exception as e:
        logger.error(f"Failed to load credentials: {e}")
        raise


@asynccontextmanager
async def matrix_client() -> AsyncIterator[AsyncClient]:
    """
    Async context manager for Matrix client operations.

    Handles client setup, session restoration, and cleanup automatically.
    Ensures client.close() is always called, preventing resource leaks.

    Usage:
        async with matrix_client() as client:
            response = await client.room_send(...)

    Yields:
        AsyncClient: Configured and authenticated Matrix client
    """
    creds = load_credentials()

    # Create data directory for E2EE store
    MATRIX_DATA_DIR.mkdir(exist_ok=True)

    client = AsyncClient(
        homeserver=creds['homeserver'],
        user=creds['user_id'],
        store_path=str(MATRIX_DATA_DIR),
    )

    # Restore session from credentials
    client.access_token = creds['access_token']
    client.device_id = creds['device_id']

    try:
        yield client
    finally:
        await client.close()