# Copyright 2026 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import asyncio
from collections.abc import Callable
from typing import Any

try:
    from admin_console.core.config import PAUSE_FILE
except ImportError:
    from apps.admin_console.core.config import PAUSE_FILE


class ServerState:
    """Encapsulates all runtime states of the debug server."""

    def __init__(self):
        self.ipc_subscribers: list[Callable[[str, Any], None]] = []
        self.ipc_server: asyncio.Server | None = None
        self.ipc_serve_task: asyncio.Task | None = None
        self.ipc_port: int | None = None
        self.is_shutting_down: bool = False

        self.current_process: asyncio.subprocess.Process | None = None
        self.current_goal: str | None = None
        self.current_profile: str | None = None
        self.active_connections: dict[str, dict[str, Any]] = {}
        self.active_session_id: str | None = None
        self.was_stopped_manually: bool = False
        self.cancelled_session_ids: set[str] = set()

        # Unified single source of truth for task queue
        self.queue_items: list[dict[str, Any]] = []
        self._wake_event: asyncio.Event | None = None
        self._shutdown_event: asyncio.Event | None = None
        self.worker_task: asyncio.Task | None = None

    @property
    def wake_event(self) -> asyncio.Event:
        try:
            loop = asyncio.get_running_loop()
        except RuntimeError:
            loop = None

        if self._wake_event is None or (
            loop
            and getattr(self._wake_event, "_loop", None) is not None
            and self._wake_event._loop != loop
        ):
            self._wake_event = asyncio.Event()
        return self._wake_event

    @property
    def shutdown_event(self) -> asyncio.Event:
        """Event set as soon as the HTTP server receives a shutdown signal."""
        try:
            loop = asyncio.get_running_loop()
        except RuntimeError:
            loop = None

        if self._shutdown_event is None or (
            loop
            and getattr(self._shutdown_event, "_loop", None) is not None
            and self._shutdown_event._loop != loop
        ):
            self._shutdown_event = asyncio.Event()
        return self._shutdown_event

    @property
    def task_queue(self) -> list[dict[str, Any]]:
        """Backward compatibility alias for queue_items."""
        return self.queue_items

    @property
    def queue_tasks(self) -> list[dict[str, Any]]:
        """Returns all currently pending tasks in the queue."""
        return [t for t in self.queue_items if isinstance(t, dict) and t.get("status") == "pending"]

    @queue_tasks.setter
    def queue_tasks(self, val: list[dict[str, Any]]):
        # Compatibility setter
        self.queue_items = list(val)

    @property
    def queue_goals(self) -> list[str]:
        """Backward compatibility helper for queue goals."""
        return [t.get("goal", "") for t in self.queue_tasks]

    @queue_goals.setter
    def queue_goals(self, val: list[Any]):
        pass

    @property
    def is_running(self) -> bool:
        has_proc = False
        if self.current_process is not None:
            if self.current_process.returncode is not None:
                has_proc = False
                self.current_process = None
            else:
                pid = getattr(self.current_process, "pid", None)
                if pid:
                    try:
                        import os

                        os.kill(pid, 0)
                        has_proc = True
                    except (ProcessLookupError, PermissionError, OSError):
                        has_proc = False
                        self.current_process = None
                else:
                    has_proc = False
                    self.current_process = None

        has_running_item = any(
            isinstance(t, dict) and t.get("status") == "running" for t in self.queue_items
        )

        has_live_connection = False
        for sid, conn in list(self.active_connections.items()):
            c_pid = conn.get("pid")
            if c_pid:
                try:
                    import os

                    os.kill(c_pid, 0)
                    has_live_connection = True
                except (ProcessLookupError, PermissionError, OSError):
                    self.active_connections.pop(sid, None)

        if not has_proc and not has_running_item and not has_live_connection:
            self.active_session_id = None
            self.current_process = None
            return False

        return True

    @property
    def is_paused(self) -> bool:
        return PAUSE_FILE.exists()

    @property
    def paused_error(self) -> str | None:
        """Return the persisted pause reason for clients that missed the SSE event."""
        if not PAUSE_FILE.exists():
            return None
        try:
            message = PAUSE_FILE.read_text(encoding="utf-8", errors="replace").strip()
        except OSError:
            return "AI model request failed. The task is paused."
        if message.startswith("LLM Error: "):
            message = message[len("LLM Error: ") :]
        return message or "AI model request failed. The task is paused."

    def add_subscriber(self, callback: Callable[[str, Any], None]):
        if callback not in self.ipc_subscribers:
            self.ipc_subscribers.append(callback)

    def remove_subscriber(self, callback: Callable[[str, Any], None]):
        if callback in self.ipc_subscribers:
            self.ipc_subscribers.remove(callback)

    def clear_queue(self):
        """Clears all pending items from the task queue."""
        self.queue_items = [t for t in self.queue_items if t.get("status") == "running"]
        if self._wake_event:
            self._wake_event.set()


# Global shared instance
state = ServerState()