#!/usr/bin/env python3
"""
umbrella-bot: Matrix bot client for the umbrella server manager.

Connects to the umbrella Unix socket and bridges commands from a Matrix
room to umbrella units. Requires matrix-nio with encryption support.

Dependencies:
    pip install matrix-nio[e2e] aiofiles

Setup:
    1. Create /etc/umbrella/bot.conf (see bot.conf.example)
    2. Run once with --setup to perform initial login and key verification
    3. Run normally or via systemd
"""

import asyncio
import json
import os
import re
import signal
import socket
import struct
import sys
import logging
import argparse
from pathlib import Path
from typing import Optional

from nio import (
    AsyncClient,
    AsyncClientConfig,
    LoginResponse,
    MatrixRoom,
    RoomMessageText,
    SyncResponse,
    crypto,
)
from nio.store import SqliteStore

# ── Logging ───────────────────────────────────────────────────────────────────

logging.basicConfig(
    level=logging.INFO,
    format="[%(asctime)s] [%(levelname)s] %(message)s",
    datefmt="%Y-%m-%d %H:%M:%S",
)
log = logging.getLogger("umbrella-bot")

# ── Config ────────────────────────────────────────────────────────────────────

DEFAULT_CONF = "/etc/umbrella/bot.conf"
DEFAULT_STORE = "/etc/umbrella/bot-store"
SOCK_PATH = "/run/umbrella/umbrella.sock"
PROTO_MAX = 65536

HELP_TEXT = """\
Umbrella bot commands:

  !status <unit>           — Show unit status
  !cmd <unit> <command>    — Send a console command
  !restart <unit>          — Restart the unit's systemd service
  !update <unit>           — Run the update action
  !action <unit> <action>  — Run a named action
  !attach <unit>           — Stream live log output to this room
  !detach <unit>           — Stop streaming log output
  !units                   — List all units
  !help                    — Show this message
"""

# ── Umbrella socket client ────────────────────────────────────────────────────

class UmbrellaClient:
    """
    Synchronous umbrella socket client.
    We use a plain blocking socket here since commands are short-lived
    and we don't need async for the request/response pattern.
    For attach (streaming), we use a separate async wrapper.
    """

    def __init__(self, sock_path: str = SOCK_PATH):
        self.sock_path = sock_path

    def _connect(self) -> socket.socket:
        s = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
        s.settimeout(10)
        try:
            s.connect(self.sock_path)
        except FileNotFoundError:
            raise RuntimeError(f"Umbrella socket not found: {self.sock_path} "
                               f"(is umbrelld running?)")
        except ConnectionRefusedError:
            raise RuntimeError("Umbrella daemon is not running")
        return s

    def _send(self, s: socket.socket, msg: dict) -> None:
        data = json.dumps(msg).encode()
        header = struct.pack(">I", len(data))
        s.sendall(header + data)

    def _recv(self, s: socket.socket) -> dict:
        header = b""
        while len(header) < 4:
            chunk = s.recv(4 - len(header))
            if not chunk:
                raise RuntimeError("Connection closed by umbrella daemon")
            header += chunk
        length = struct.unpack(">I", header)[0]
        if length > PROTO_MAX:
            raise RuntimeError(f"Message too large: {length}")
        data = b""
        while len(data) < length:
            chunk = s.recv(length - len(data))
            if not chunk:
                raise RuntimeError("Connection closed mid-message")
            data += chunk
        return json.loads(data.decode())

    def command(self, msg: dict) -> dict:
        """Send a command and return the response."""
        s = self._connect()
        try:
            self._send(s, msg)
            return self._recv(s)
        finally:
            s.close()

    def list_units(self) -> list:
        resp = self.command({"cmd": "list"})
        return resp.get("units", [])

    def status(self, unit: str) -> dict:
        return self.command({"cmd": "status", "unit": unit})

    def send_input(self, unit: str, data: str) -> dict:
        return self.command({"cmd": "input", "unit": unit,
                             "data": data + "\n"})

    def run_action(self, unit: str, action: str) -> dict:
        return self.command({"cmd": "action", "unit": unit, "action": action})


# ── Attach session: streams output from umbrella to a Matrix room ─────────────

class AttachSession:
    """
    Maintains a persistent connection to umbrella for a specific unit,
    forwarding live output to a Matrix room.
    """

    def __init__(self, unit: str, room_id: str,
                 matrix_client: "AsyncClient",
                 sock_path: str = SOCK_PATH):
        self.unit = unit
        self.room_id = room_id
        self.matrix_client = matrix_client
        self.sock_path = sock_path
        self._task: Optional[asyncio.Task] = None
        self._sock: Optional[socket.socket] = None

    async def start(self):
        if self._task and not self._task.done():
            return  # already running
        self._task = asyncio.create_task(self._stream())

    async def stop(self):
        if self._task:
            self._task.cancel()
            try:
                await self._task
            except asyncio.CancelledError:
                pass
        if self._sock:
            try:
                self._sock.close()
            except Exception:
                pass
            self._sock = None

    async def _stream(self):
        loop = asyncio.get_event_loop()

        def connect_and_attach():
            s = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
            s.settimeout(10)
            s.connect(self.sock_path)
            # Send attach command
            msg = json.dumps({"cmd": "attach", "unit": self.unit}).encode()
            s.sendall(struct.pack(">I", len(msg)) + msg)
            # Read ok response
            hdr = b""
            while len(hdr) < 4:
                hdr += s.recv(4 - len(hdr))
            length = struct.unpack(">I", hdr)[0]
            resp_data = b""
            while len(resp_data) < length:
                resp_data += s.recv(length - len(resp_data))
            s.settimeout(None)  # non-blocking from here
            s.setblocking(False)
            return s

        try:
            self._sock = await loop.run_in_executor(None, connect_and_attach)
        except Exception as e:
            log.error(f"attach: failed to connect for {self.unit}: {e}")
            return

        buf = b""
        log.info(f"attach: streaming {self.unit} to room {self.room_id}")

        try:
            while True:
                # Read available data from socket
                try:
                    chunk = await loop.run_in_executor(
                        None, lambda: self._recv_one_nonblock()
                    )
                    if chunk is None:
                        await asyncio.sleep(0.05)
                        continue
                    if chunk == {}:
                        break  # disconnected
                except asyncio.CancelledError:
                    raise
                except Exception as e:
                    log.error(f"attach: read error for {self.unit}: {e}")
                    break

                if chunk.get("type") == "output":
                    data = chunk.get("data", "")
                    history = chunk.get("history", False)
                    if data and not history:
                        # Send to Matrix room, wrapped in code block
                        await self.matrix_client.room_send(
                            self.room_id,
                            "m.room.message",
                            {
                                "msgtype": "m.text",
                                "body": f"```\n{data.rstrip()}\n```",
                                "format": "org.matrix.custom.html",
                                "formatted_body": f"<pre><code>{data.rstrip()}</code></pre>",
                            },
                            ignore_unverified_devices=True,
                        )
        except asyncio.CancelledError:
            pass
        finally:
            if self._sock:
                # Send detach
                try:
                    msg = json.dumps({"cmd": "detach"}).encode()
                    self._sock.setblocking(True)
                    self._sock.sendall(struct.pack(">I", len(msg)) + msg)
                except Exception:
                    pass
                self._sock.close()
                self._sock = None

    def _recv_one_nonblock(self) -> Optional[dict]:
        """Try to read one message from the non-blocking socket. Returns None if no data yet."""
        try:
            hdr = self._sock.recv(4)
            if not hdr:
                return {}  # disconnected
            if len(hdr) < 4:
                return None
            length = struct.unpack(">I", hdr)[0]
            data = b""
            self._sock.setblocking(True)
            while len(data) < length:
                chunk = self._sock.recv(length - len(data))
                if not chunk:
                    return {}
                data += chunk
            self._sock.setblocking(False)
            return json.loads(data.decode())
        except BlockingIOError:
            return None


# ── Power level check ─────────────────────────────────────────────────────────

async def get_user_power_level(client: AsyncClient,
                                room_id: str, user_id: str) -> int:
    """
    Fetch the power level for a user in a room.
    Returns 0 if the user is not found or on error.
    """
    try:
        resp = await client.room_get_state_event(
            room_id, "m.room.power_levels", ""
        )
        if hasattr(resp, "content"):
            users = resp.content.get("users", {})
            default = resp.content.get("users_default", 0)
            return users.get(user_id, default)
    except Exception as e:
        log.warning(f"Could not get power level for {user_id}: {e}")
    return 0


# ── Command dispatch ──────────────────────────────────────────────────────────

async def handle_command(
    client: AsyncClient,
    umbrella: UmbrellaClient,
    attach_sessions: dict,
    room: MatrixRoom,
    sender: str,
    text: str,
    config: dict,
) -> Optional[str]:
    """
    Parse and dispatch a bot command. Returns a reply string or None.
    """
    parts = text.strip().split(None, 3)
    if not parts:
        return None

    cmd = parts[0].lower()

    # Check power level
    power = await get_user_power_level(client, room.room_id, sender)
    if power < 50:
        return f"❌ Permission denied. Requires power level ≥ 50 (you have {power})."

    try:
        if cmd == "!help":
            return HELP_TEXT

        elif cmd == "!units":
            units = umbrella.list_units()
            if not units:
                return "No units loaded."
            lines = ["**Units:**"]
            for u in units:
                lines.append(f"  `{u['name']}` — {u['display']} [{u['state']}]")
            return "\n".join(lines)

        elif cmd == "!status":
            if len(parts) < 2:
                return "Usage: `!status <unit>`"
            unit = parts[1]
            resp = umbrella.status(unit)
            if resp.get("type") == "error":
                return f"❌ {resp['message']}"
            return (
                f"**{resp.get('display', unit)}**\n"
                f"State: `{resp.get('state', 'unknown')}`"
            )

        elif cmd == "!cmd":
            if len(parts) < 3:
                return "Usage: `!cmd <unit> <command>`"
            unit = parts[1]
            command = " ".join(parts[2:])
            resp = umbrella.send_input(unit, command)
            if resp.get("type") == "error":
                return f"❌ {resp['message']}"
            return f"✓ Sent: `{command}`"

        elif cmd == "!restart":
            if len(parts) < 2:
                return "Usage: `!restart <unit>`"
            unit = parts[1]
            resp = umbrella.run_action(unit, "restart")
            if resp.get("type") == "error":
                return f"❌ {resp['message']}"
            return f"✓ Restart dispatched for `{unit}`"

        elif cmd == "!update":
            if len(parts) < 2:
                return "Usage: `!update <unit>`"
            unit = parts[1]
            resp = umbrella.run_action(unit, "update")
            if resp.get("type") == "error":
                return f"❌ {resp['message']}"
            return f"✓ Update dispatched for `{unit}`"

        elif cmd == "!action":
            if len(parts) < 3:
                return "Usage: `!action <unit> <action>`"
            unit = parts[1]
            action = parts[2]
            resp = umbrella.run_action(unit, action)
            if resp.get("type") == "error":
                return f"❌ {resp['message']}"
            return f"✓ Action `{action}` dispatched for `{unit}`"

        elif cmd == "!attach":
            if len(parts) < 2:
                return "Usage: `!attach <unit>`"
            unit = parts[1]
            key = (room.room_id, unit)
            if key in attach_sessions:
                return f"Already streaming `{unit}` to this room."
            session = AttachSession(unit, room.room_id, client)
            attach_sessions[key] = session
            await session.start()
            return f"📡 Streaming `{unit}` output to this room. Use `!detach {unit}` to stop."

        elif cmd == "!detach":
            if len(parts) < 2:
                return "Usage: `!detach <unit>`"
            unit = parts[1]
            key = (room.room_id, unit)
            if key not in attach_sessions:
                return f"`{unit}` is not being streamed to this room."
            await attach_sessions[key].stop()
            del attach_sessions[key]
            return f"⏹ Stopped streaming `{unit}`."

    except RuntimeError as e:
        return f"❌ Umbrella error: {e}"
    except Exception as e:
        log.exception(f"Command error: {e}")
        return f"❌ Internal error: {e}"

    return None


# ── Bot core ──────────────────────────────────────────────────────────────────

async def run_bot(config: dict):
    store_path = config.get("store_path", DEFAULT_STORE)
    os.makedirs(store_path, exist_ok=True)

    client_config = AsyncClientConfig(
        max_limit_exceeded=0,
        max_timeouts=0,
        store_sync_tokens=True,
        encryption_enabled=True,
    )

    client = AsyncClient(
        homeserver=config["homeserver"],
        user=config["user_id"],
        device_id=config.get("device_id", "UMBRELLA_BOT"),
        store_path=store_path,
        config=client_config,
    )

    umbrella = UmbrellaClient(config.get("socket_path", SOCK_PATH))
    attach_sessions = {}
    room_id = config["room_id"]

    # Login
    log.info(f"Logging in as {config['user_id']}...")
    resp = await client.login(
        password=config["password"],
        device_name="umbrella-bot",
    )
    if not isinstance(resp, LoginResponse):
        log.error(f"Login failed: {resp}")
        return

    log.info(f"Logged in. Device ID: {client.device_id}")

    # Load encryption keys
    if client.should_upload_keys:
        await client.keys_upload()
    if client.should_query_keys:
        await client.keys_query()

    # Message callback
    async def on_message(room: MatrixRoom, event: RoomMessageText):
        # Only handle messages in our configured room
        if room.room_id != room_id:
            return
        # Ignore our own messages
        if event.sender == config["user_id"]:
            return
        # Only handle messages that start with !
        body = event.body.strip()
        if not body.startswith("!"):
            return

        log.info(f"Command from {event.sender}: {body}")

        reply = await handle_command(
            client, umbrella, attach_sessions,
            room, event.sender, body, config
        )
        if reply:
            await client.room_send(
                room_id,
                "m.room.message",
                {
                    "msgtype": "m.text",
                    "body": reply,
                    "format": "org.matrix.custom.html",
                    "formatted_body": reply.replace("\n", "<br>"),
                },
                ignore_unverified_devices=True,
            )

    client.add_event_callback(on_message, RoomMessageText)

    # Graceful shutdown
    loop = asyncio.get_event_loop()
    stop_event = asyncio.Event()

    def _signal_handler():
        log.info("Shutting down...")
        stop_event.set()

    loop.add_signal_handler(signal.SIGTERM, _signal_handler)
    loop.add_signal_handler(signal.SIGINT, _signal_handler)

    log.info(f"Syncing, watching room {room_id}")

    # Initial sync
    await client.sync(timeout=10000)
    if client.should_query_keys:
        await client.keys_query()

    await client.joined_members(room_id)

    # Main sync loop
    async def sync_loop():
        while not stop_event.is_set():
            resp = await client.sync(timeout=30000, full_state=False)
            if isinstance(resp, SyncResponse):
                if client.should_upload_keys:
                    await client.keys_upload()
                if client.should_query_keys:
                    await client.keys_query()
    
    sync_task = asyncio.create_task(sync_loop())

    await stop_event.wait()

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

    # Stop all attach sessions
    for session in attach_sessions.values():
        await session.stop()

    await client.close()
    log.info("Bot stopped.")


# ── Setup mode ────────────────────────────────────────────────────────────────

async def run_setup(config: dict):
    """
    First-run setup: login, generate device keys, print device ID.
    Run this once before starting the bot normally.
    """
    store_path = config.get("store_path", DEFAULT_STORE)
    os.makedirs(store_path, exist_ok=True)

    client = AsyncClient(
        homeserver=config["homeserver"],
        user=config["user_id"],
        device_id=config.get("device_id", "UMBRELLA_BOT"),
        store_path=store_path,
        config=AsyncClientConfig(encryption_enabled=True),
    )

    print(f"Logging in as {config['user_id']}...")
    resp = await client.login(
        password=config["password"],
        device_name="umbrella-bot",
    )
    if not isinstance(resp, LoginResponse):
        print(f"Login failed: {resp}")
        return

    print(f"Logged in successfully.")
    print(f"Device ID: {client.device_id}")
    print(f"Add this to your bot.conf: device_id = {client.device_id}")

    if client.should_upload_keys:
        await client.keys_upload()
        print("Encryption keys uploaded.")

    print("\nSetup complete. You can now run the bot normally.")
    print("Note: you may need to verify this device from another session")
    print("if your room requires verified devices.")

    await client.close()


# ── Config loading ────────────────────────────────────────────────────────────

def load_config(path: str) -> dict:
    config = {}
    with open(path) as f:
        for line in f:
            line = line.strip()
            if not line or line.startswith("#"):
                continue
            if "=" not in line:
                continue
            key, _, value = line.partition("=")
            config[key.strip()] = value.strip()

    required = ["homeserver", "user_id", "password", "room_id"]
    for key in required:
        if key not in config:
            raise ValueError(f"Missing required config key: {key}")

    return config


# ── Entry point ───────────────────────────────────────────────────────────────

def main():
    parser = argparse.ArgumentParser(description="Umbrella Matrix bot")
    parser.add_argument("-c", "--config", default=DEFAULT_CONF,
                        help=f"Config file (default: {DEFAULT_CONF})")
    parser.add_argument("--setup", action="store_true",
                        help="Run first-time setup and exit")
    args = parser.parse_args()

    try:
        config = load_config(args.config)
    except FileNotFoundError:
        print(f"Config file not found: {args.config}")
        print(f"Create it based on bot.conf.example")
        sys.exit(1)
    except ValueError as e:
        print(f"Config error: {e}")
        sys.exit(1)

    if args.setup:
        asyncio.run(run_setup(config))
    else:
        asyncio.run(run_bot(config))


if __name__ == "__main__":
    main()