import asyncio
import json
import logging
import signal
import sys
from pathlib import Path

from nio import (
    AsyncClient,
    AsyncClientConfig,
    InviteMemberEvent,
    LoginResponse,
    RoomMemberEvent,
    RoomMessageText,
    UnknownEvent,
)

from config import (
    MATRIX_HOMESERVER,
    MATRIX_USER_ID,
    MATRIX_ACCESS_TOKEN,
    MATRIX_DEVICE_ID,
    MATRIX_PASSWORD,
    LOG_LEVEL,
    ConfigValidator,
)
from callbacks import Callbacks
from utils import setup_logging
from welcome import post_welcome_message

logger = setup_logging(LOG_LEVEL)

CREDENTIALS_FILE = Path("credentials.json")
STORE_PATH = Path("nio_store")


def save_credentials(resp, homeserver):
    data = {
        "homeserver": homeserver,
        "user_id": resp.user_id,
        "device_id": resp.device_id,
        "access_token": resp.access_token,
    }
    CREDENTIALS_FILE.write_text(json.dumps(data, indent=2))
    logger.info("Credentials saved to %s", CREDENTIALS_FILE)


async def trust_devices(client: AsyncClient):
    """Query keys and trust all devices for all users we share rooms with."""
    if not client.olm:
        logger.warning("Olm not loaded, skipping device trust")
        return

    # Collect all users across all joined rooms
    users = set()
    for room in client.rooms.values():
        for user_id in room.users:
            users.add(user_id)

    # Fetch device keys so the store is complete
    if users:
        await client.keys_query()

    # Trust every device
    for user_id, devices in client.device_store.items():
        for device_id, olm_device in devices.items():
            if not client.olm.is_device_verified(olm_device):
                client.verify_device(olm_device)
    logger.info("Trusted all known devices (%d users)", len(users))


async def main():
    errors = ConfigValidator.validate()
    if errors:
        for e in errors:
            logger.error(e)
        sys.exit(1)

    STORE_PATH.mkdir(exist_ok=True)

    client_config = AsyncClientConfig(
        store_sync_tokens=True,
        encryption_enabled=True,
        store_name="matrixbot",
    )

    client = AsyncClient(
        MATRIX_HOMESERVER,
        MATRIX_USER_ID,
        device_id=MATRIX_DEVICE_ID or None,
        config=client_config,
        store_path=str(STORE_PATH),
    )

    # Try saved credentials first, then .env token, then password login
    logged_in = False
    has_creds = False

    if CREDENTIALS_FILE.exists():
        creds = json.loads(CREDENTIALS_FILE.read_text())
        client.access_token = creds["access_token"]
        client.user_id = creds["user_id"]
        client.device_id = creds["device_id"]
        has_creds = True
        logger.info("Loaded credentials from %s", CREDENTIALS_FILE)
    elif MATRIX_ACCESS_TOKEN and MATRIX_DEVICE_ID:
        client.access_token = MATRIX_ACCESS_TOKEN
        client.user_id = MATRIX_USER_ID
        client.device_id = MATRIX_DEVICE_ID
        has_creds = True
        logger.info("Using access token from .env")

    # Load the olm/e2ee store only if we have a device_id
    if has_creds:
        client.load_store()

    # Test the token with a sync; if it fails, fall back to password login
    if has_creds and client.access_token:
        logger.info("Testing existing access token...")
        sync_resp = await client.sync(timeout=30000, full_state=True)
        if hasattr(sync_resp, "next_batch"):
            logged_in = True
            logger.info("Existing token is valid")
        else:
            logger.warning("Existing token is invalid, will try password login")
            client.access_token = ""

    if not logged_in:
        if not MATRIX_PASSWORD:
            logger.error("No valid token and no MATRIX_PASSWORD set — cannot authenticate")
            await client.close()
            sys.exit(1)
        logger.info("Logging in with password...")
        login_resp = await client.login(MATRIX_PASSWORD, device_name="LotusBot")
        if isinstance(login_resp, LoginResponse):
            logger.info("Password login successful, device_id=%s", login_resp.device_id)
            save_credentials(login_resp, MATRIX_HOMESERVER)
            client.load_store()
            sync_resp = await client.sync(timeout=30000, full_state=True)
        else:
            logger.error("Password login failed: %s", login_resp)
            await client.close()
            sys.exit(1)

    callbacks = Callbacks(client)
    client.add_event_callback(callbacks.message, RoomMessageText)
    client.add_event_callback(callbacks.reaction, UnknownEvent)
    client.add_event_callback(callbacks.member, RoomMemberEvent)

    # Auto-accept room invites
    async def _auto_accept_invite(room, event):
        if event.membership == "invite" and event.state_key == MATRIX_USER_ID:
            logger.info("Auto-accepting invite to %s", room.room_id)
            await client.join(room.room_id)

    client.add_event_callback(_auto_accept_invite, InviteMemberEvent)

    # Graceful shutdown
    loop = asyncio.get_running_loop()
    shutdown_event = asyncio.Event()

    def _signal_handler():
        logger.info("Shutdown signal received")
        shutdown_event.set()

    for sig in (signal.SIGTERM, signal.SIGINT):
        loop.add_signal_handler(sig, _signal_handler)

    # Mark startup complete from the initial sync
    if hasattr(sync_resp, "next_batch"):
        callbacks.startup_sync_token = sync_resp.next_batch
        logger.info("Initial sync complete, token: %s", sync_resp.next_batch[:20])
    else:
        logger.error("Initial sync failed: %s", sync_resp)
        await client.close()
        sys.exit(1)

    # Trust devices after initial sync loads the device store
    await trust_devices(client)

    # Post welcome message (idempotent — only posts if not already stored)
    await post_welcome_message(client)

    logger.info("Bot ready as %s — listening for commands", MATRIX_USER_ID)

    # Run sync_forever in a task so we can cancel on shutdown
    async def _sync_loop():
        await client.sync_forever(timeout=30000, full_state=False)

    sync_task = asyncio.create_task(_sync_loop())

    await shutdown_event.wait()
    sync_task.cancel()
    try:
        await sync_task
    except asyncio.CancelledError:
        pass

    await client.close()
    logger.info("Bot shut down cleanly")


if __name__ == "__main__":
    asyncio.run(main())