"""
ThreadRegistry — manages the lifecycle of all per-server background threads.

One instance is created at app startup and stored in app.state.thread_registry.
Also provides class-level methods for convenience (called from ServerService).

Thread set per server:
  - LogTailThread          (started if adapter has "log_parser" capability and log_path is known)
  - MetricsCollectorThread (always started)
  - ProcessMonitorThread   (always started)
  - RemoteAdminPollerThread (started only if adapter has "remote_admin" capability)

Key methods:
  start_server_threads(server_id, db)    — start all threads for a server
  stop_server_threads(server_id)         — stop all threads for a server
  reattach_server_threads(server_id, db) — re-attach threads without restarting process
  stop_all()                             — called at app shutdown
"""
from __future__ import annotations

import logging
import queue

from adapters.registry import GameAdapterRegistry
from core.dal.config_repository import ConfigRepository
from core.dal.server_repository import ServerRepository
from core.threads.log_tail import LogTailThread
from core.threads.metrics_collector import MetricsCollectorThread
from core.threads.process_monitor import ProcessMonitorThread
from core.threads.remote_admin_poller import RemoteAdminPollerThread

logger = logging.getLogger(__name__)

# Module-level singleton for convenience (used by ServerService)
_instance: ThreadRegistry | None = None


class ThreadRegistry:
    """
    Manages all background threads for all running servers.
    """

    def __init__(
        self,
        process_manager,
        adapter_registry: GameAdapterRegistry | None = None,
        global_broadcast_queue: queue.Queue | None = None,
    ) -> None:
        self._process_manager = process_manager
        self._adapter_registry = adapter_registry or GameAdapterRegistry
        self._broadcast_queue = global_broadcast_queue or queue.Queue(maxsize=1000)
        self._bundles: dict[int, dict] = {}  # server_id -> thread bundle

    # ── Class-level convenience API ──

    @classmethod
    def _get_instance(cls) -> "ThreadRegistry | None":
        return _instance

    @classmethod
    def set_instance(cls, registry: "ThreadRegistry") -> None:
        global _instance
        _instance = registry

    @classmethod
    def start_server_threads(cls, server_id: int, db) -> None:
        """Class-level convenience — starts threads for a server using the singleton."""
        registry = cls._get_instance()
        if registry is not None:
            registry._start_server_threads(server_id, db)

    @classmethod
    def stop_server_threads(cls, server_id: int) -> None:
        """Class-level convenience — stops threads for a server using the singleton."""
        registry = cls._get_instance()
        if registry is not None:
            registry._stop_server_threads(server_id)

    @classmethod
    def reattach_server_threads(cls, server_id: int, db) -> None:
        """Class-level convenience — re-attaches threads for a recovered server."""
        registry = cls._get_instance()
        if registry is not None:
            registry._reattach_server_threads(server_id, db)

    @classmethod
    def stop_all(cls) -> None:
        """Class-level convenience — stops all threads."""
        registry = cls._get_instance()
        if registry is not None:
            registry._stop_all()

    @classmethod
    def get_rcon_client(cls, server_id: int):
        """Return the live Arma3RemoteAdmin client for a running server, or None."""
        registry = cls._get_instance()
        if registry is None:
            return None
        bundle = registry._bundles.get(server_id)
        if bundle is None:
            return None
        poller = bundle.get("rcon_poller")
        if poller is None or not poller.is_alive():
            return None
        return getattr(poller, "_client", None)

    # ── Instance methods ──

    def _start_server_threads(self, server_id: int, db) -> None:
        if server_id in self._bundles:
            logger.warning(
                "ThreadRegistry: threads already exist for server %d — stopping first",
                server_id,
            )
            self._stop_server_threads(server_id)

        bundle = self._build_bundle(server_id, db)
        self._bundles[server_id] = bundle
        self._start_bundle(server_id, bundle)

    def _stop_server_threads(self, server_id: int) -> None:
        bundle = self._bundles.pop(server_id, None)
        if bundle is None:
            return
        self._stop_bundle(server_id, bundle)

    def _reattach_server_threads(self, server_id: int, db) -> None:
        logger.info("ThreadRegistry: reattaching threads for server %d", server_id)
        self._start_server_threads(server_id, db)

    def _stop_all(self) -> None:
        server_ids = list(self._bundles.keys())
        for server_id in server_ids:
            self._stop_server_threads(server_id)
        logger.info("ThreadRegistry: all threads stopped")

    def get_thread_count(self, server_id: int) -> int:
        """Returns the number of running threads for a server."""
        bundle = self._bundles.get(server_id)
        if bundle is None:
            return 0
        return sum(
            1
            for key in ("log_tail", "metrics", "monitor", "rcon_poller")
            if bundle.get(key) is not None and bundle[key].is_alive()
        )

    # ── Bundle construction ──

    def _build_bundle(self, server_id: int, db) -> dict:
        """Reads server + config data from DB and constructs (but does not start) the thread bundle."""
        server_repo = ServerRepository(db)
        config_repo = ConfigRepository(db)

        server = server_repo.get_by_id(server_id)
        if server is None:
            raise ValueError(f"Server {server_id} not found in database")

        game_type = server["game_type"]
        adapter = self._adapter_registry.get(game_type)

        # Log path: RPT files live next to the server exe, not in the languard data dir
        log_path = None
        if adapter.has_capability("log_parser"):
            log_parser = adapter.get_log_parser()
            from pathlib import Path
            exe_dir = Path(server["exe_path"]).parent
            resolver = log_parser.get_log_file_resolver(server_id)
            resolved = resolver(exe_dir)
            if resolved is not None:
                log_path = str(resolved)

        bundle: dict = {
            "log_tail": None,
            "metrics": None,
            "monitor": None,
            "rcon_poller": None,
        }

        # Always: ProcessMonitorThread
        bundle["monitor"] = ProcessMonitorThread(
            server_id=server_id,
            process_manager=self._process_manager,
            broadcast_queue=self._broadcast_queue,
        )

        # Always: MetricsCollectorThread
        bundle["metrics"] = MetricsCollectorThread(
            server_id=server_id,
            process_manager=self._process_manager,
            broadcast_queue=self._broadcast_queue,
        )

        # Conditional: LogTailThread
        if log_path and adapter.has_capability("log_parser"):
            log_parser = adapter.get_log_parser()
            bundle["log_tail"] = LogTailThread(
                server_id=server_id,
                log_path=log_path,
                log_parser=log_parser,
                broadcast_queue=self._broadcast_queue,
            )

        # Conditional: RemoteAdminPollerThread
        if adapter.has_capability("remote_admin"):
            remote_admin = adapter.get_remote_admin()
            if remote_admin is not None:
                # Get RCon password from config
                rcon_password = self._get_remote_admin_password(server_id, config_repo)
                if rcon_password:
                    try:
                        rcon_port = server.get("rcon_port") or server.get("game_port", 0) + 1
                        client = remote_admin.create_client(
                            host="127.0.0.1",
                            port=rcon_port,
                            password=rcon_password,
                        )
                        bundle["rcon_poller"] = RemoteAdminPollerThread(
                            server_id=server_id,
                            remote_admin_client=client,
                            broadcast_queue=self._broadcast_queue,
                        )
                    except Exception as exc:
                        logger.warning(
                            "ThreadRegistry: could not create RCon client for server %d: %s",
                            server_id, exc,
                        )

        return bundle

    def _start_bundle(self, server_id: int, bundle: dict) -> None:
        started = []
        for key in ("monitor", "metrics", "log_tail", "rcon_poller"):
            thread = bundle.get(key)
            if thread is not None:
                thread.start()
                started.append(key)
        logger.info("ThreadRegistry: started threads for server %d: %s", server_id, started)

    def _stop_bundle(self, server_id: int, bundle: dict) -> None:
        for key in ("rcon_poller", "log_tail", "metrics", "monitor"):
            thread = bundle.get(key)
            if thread is not None and thread.is_alive():
                thread.stop_and_join(timeout=5.0)
        logger.info("ThreadRegistry: stopped all threads for server %d", server_id)

    # ── Helpers ──

    def _get_remote_admin_password(
        self, server_id: int, config_repo: ConfigRepository
    ) -> str | None:
        """Read the RCon password from the rcon config section."""
        # Need to decrypt sensitive fields
        from adapters.registry import GameAdapterRegistry
        try:
            server = ServerRepository(config_repo._db).get_by_id(server_id)
            if server is None:
                return None
            adapter = self._adapter_registry.get(server["game_type"])
            config_gen = adapter.get_config_generator()
            sensitive = config_gen.get_sensitive_fields("rcon") if "rcon" in config_gen.get_sections() else []
        except Exception as exc:
            logger.debug("Could not determine sensitive fields for RCon config: %s", exc)
            sensitive = []

        rcon_section = config_repo.get_section(server_id, "rcon", sensitive)
        if rcon_section is None:
            return None
        return rcon_section.get("password") or None