# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the BSD-style license found in the
# LICENSE file in the root directory of this source tree.

"""Code Fixer Environment Client."""

import asyncio
import inspect
import logging
from typing import Dict

from openenv.core import EnvClient
from openenv.core.client_types import StepResult
from openenv.core.env_server.types import State

from rl_code_fix_env.models import CodeFixerAction, CodeFixerObservation

log = logging.getLogger(__name__)

class CodeFixerEnv(
    EnvClient[CodeFixerAction, CodeFixerObservation, State]
):
    """
    Client for the Code Fixer Environment.

    This client maintains a persistent WebSocket connection to the environment server,
    enabling efficient multi-step interactions with lower latency.
    Each client instance has its own dedicated environment session on the server.

    Example:
        >>> # Connect to a running server
        >>> with CodeFixerEnv(base_url="http://localhost:8000") as client:
        ...     result = client.reset()
        ...     print(result.observation.code)
        ...
        ...     result = client.step(CodeFixerAction(type="run_tests"))
        ...     print(result.observation.test_passed)

    Example with Docker:
        >>> # Automatically start container and connect
        >>> client = CodeFixerEnv.from_docker_image("code_fixer-env:latest")
        >>> try:
        ...     result = client.reset()
        ...     result = client.step(CodeFixerAction(type="run_tests"))
        ... finally:
        ...     client.close()
    """

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self._loop = asyncio.new_event_loop()
        # Store init args for reconnection
        self._init_args = args
        self._init_kwargs = kwargs

    def _run_sync(self, result):
        """Run coroutine results on this client's dedicated event loop."""
        if inspect.iscoroutine(result):
            return self._loop.run_until_complete(result)
        return result

    def _reconnect(self) -> None:
        """
        Tear down the dead event loop and WebSocket connection, then
        re-initialise so the next call works cleanly.

        Called automatically by reset() and step() when a 1011 / timeout
        error is detected after an idle period.
        """
        log.warning("[CodeFixerEnv] WebSocket timed out  reconnecting...")
        # Close the old loop gracefully
        try:
            self._run_sync(super().close())
        except Exception:
            pass
        if not self._loop.is_closed():
            self._loop.close()

        # Re-initialise: fresh loop + fresh base-class state
        self._loop = asyncio.new_event_loop()
        super().__init__(*self._init_args, **self._init_kwargs)
        log.warning("[CodeFixerEnv] Reconnected successfully.")

    @staticmethod
    def _is_reconnectable_ws_error(exc: Exception) -> bool:
        err = str(exc).lower()
        reconnect_markers = (
            "1011",
            "1006",
            "keepalive",
            "timed out",
            "closed",
            "close frame",
            "connection closed",
            "connectionclosed",
            "websocket",
        )
        return any(marker in err for marker in reconnect_markers)

    def reset(self):
        """Reset the environment  auto-reconnects if the WebSocket died."""
        try:
            return self._run_sync(super().reset())
        except Exception as exc:
            if self._is_reconnectable_ws_error(exc):
                self._reconnect()
                return self._run_sync(super().reset())  # one retry
            raise

    def step(self, action: CodeFixerAction):
        """Execute a step  auto-reconnects if the WebSocket died."""
        try:
            return self._run_sync(super().step(action))
        except Exception as exc:
            if self._is_reconnectable_ws_error(exc):
                self._reconnect()
                return self._run_sync(super().step(action))  # one retry
            raise

    def close(self):
        """Close client resources and the dedicated event loop safely."""
        try:
            self._run_sync(super().close())
        finally:
            if not self._loop.is_closed():
                self._loop.close()

    def _step_payload(self, action: CodeFixerAction) -> Dict:
        """
        Convert CodeFixerAction to JSON payload for step message.

        Args:
            action: CodeFixerAction instance

        Returns:
            Dictionary representation suitable for JSON encoding
        """
        return {
            "type": action.type,
            "payload": action.payload,
        }

    def _parse_result(self, payload: Dict) -> StepResult[CodeFixerObservation]:
        """
        Parse server response into StepResult[CodeFixerObservation].

        Args:
            payload: JSON response data from server

        Returns:
            StepResult with CodeFixerObservation
        """
        obs_data = payload.get("observation", {})
        observation = CodeFixerObservation(
            code=obs_data.get("code", ""),
            logs=obs_data.get("logs"),
            test_score=float(obs_data.get("test_score", 0.0)),
            total_tests=obs_data.get("total_tests", 1),
            steps=obs_data.get("steps", 0),
            done=obs_data.get("done", payload.get("done", False)),
            reward=obs_data.get("reward", payload.get("reward")),
        )

        return StepResult(
            observation=observation,
            reward=payload.get("reward"),
            done=payload.get("done", False),
        )

    def _parse_state(self, payload: Dict) -> State:
        """
        Parse server response into State object.

        Args:
            payload: JSON response from state request

        Returns:
            State object with episode_id and step_count
        """
        return State(
            episode_id=payload.get("episode_id"),
            step_count=payload.get("step_count", 0),
        )