sdb2-backend/app/services/task_handlers.py

"""Task execution handlers for different task types."""

from collections.abc import Callable

from sqlmodel.ext.asyncio.session import AsyncSession

from app.core.logging import get_logger
from app.models.scheduled_task import ScheduledTask, TaskType
from app.repositories.playlist import PlaylistRepository
from app.repositories.sound import SoundRepository
from app.services.credit import CreditService
from app.services.player import PlayerService

logger = get_logger(__name__)


class TaskExecutionError(Exception):
    """Exception raised when task execution fails."""



class TaskHandlerRegistry:
    """Registry for task execution handlers."""

    def __init__(
        self,
        db_session: AsyncSession,
        db_session_factory: Callable[[], AsyncSession],
        credit_service: CreditService,
        player_service: PlayerService,
    ) -> None:
        """Initialize the task handler registry."""
        self.db_session = db_session
        self.db_session_factory = db_session_factory
        self.credit_service = credit_service
        self.player_service = player_service
        self.sound_repository = SoundRepository(db_session)
        self.playlist_repository = PlaylistRepository(db_session)

        # Register handlers
        self._handlers = {
            TaskType.CREDIT_RECHARGE: self._handle_credit_recharge,
            TaskType.PLAY_SOUND: self._handle_play_sound,
            TaskType.PLAY_PLAYLIST: self._handle_play_playlist,
        }

    async def execute_task(self, task: ScheduledTask) -> None:
        """Execute a task based on its type."""
        handler = self._handlers.get(task.task_type)
        if not handler:
            raise TaskExecutionError(f"No handler registered for task type: {task.task_type}")

        logger.info(f"Executing task {task.id} ({task.task_type.value}): {task.name}")

        try:
            await handler(task)
            logger.info(f"Task {task.id} executed successfully")
        except Exception as e:
            logger.exception(f"Task {task.id} execution failed: {e!s}")
            raise TaskExecutionError(f"Task execution failed: {e!s}") from e

    async def _handle_credit_recharge(self, task: ScheduledTask) -> None:
        """Handle credit recharge task."""
        parameters = task.parameters
        user_id = parameters.get("user_id")

        if user_id:
            # Recharge specific user
            try:
                user_id_int = int(user_id)
            except (ValueError, TypeError) as e:
                raise TaskExecutionError(f"Invalid user_id format: {user_id}") from e

            stats = await self.credit_service.recharge_user_credits(user_id_int)
            logger.info(f"Recharged credits for user {user_id}: {stats}")
        else:
            # Recharge all users (system task)
            stats = await self.credit_service.recharge_all_users_credits()
            logger.info(f"Recharged credits for all users: {stats}")

    async def _handle_play_sound(self, task: ScheduledTask) -> None:
        """Handle play sound task."""
        parameters = task.parameters
        sound_id = parameters.get("sound_id")

        if not sound_id:
            raise TaskExecutionError("sound_id parameter is required for PLAY_SOUND tasks")

        try:
            # Handle both integer and string sound IDs
            sound_id_int = int(sound_id)
        except (ValueError, TypeError) as e:
            raise TaskExecutionError(f"Invalid sound_id format: {sound_id}") from e

        # Check if this is a user task (has user_id)
        if task.user_id:
            # User task: use credit-aware playback
            from app.services.vlc_player import VLCPlayerService

            vlc_service = VLCPlayerService(self.db_session_factory)
            try:
                result = await vlc_service.play_sound_with_credits(sound_id_int, task.user_id)
                logger.info(f"Played sound {result.get('sound_name', sound_id)} via scheduled task for user {task.user_id} (credits deducted: {result.get('credits_deducted', 0)})")
            except Exception as e:
                # Convert HTTP exceptions or credit errors to task execution errors
                raise TaskExecutionError(f"Failed to play sound with credits: {e!s}") from e
        else:
            # System task: play without credit deduction
            sound = await self.sound_repository.get_by_id(sound_id_int)
            if not sound:
                raise TaskExecutionError(f"Sound not found: {sound_id}")

            from app.services.vlc_player import VLCPlayerService

            vlc_service = VLCPlayerService(self.db_session_factory)
            success = await vlc_service.play_sound(sound)

            if not success:
                raise TaskExecutionError(f"Failed to play sound {sound.filename}")

            logger.info(f"Played sound {sound.filename} via scheduled system task")

    async def _handle_play_playlist(self, task: ScheduledTask) -> None:
        """Handle play playlist task."""
        parameters = task.parameters
        playlist_id = parameters.get("playlist_id")
        play_mode = parameters.get("play_mode", "continuous")
        shuffle = parameters.get("shuffle", False)

        if not playlist_id:
            raise TaskExecutionError("playlist_id parameter is required for PLAY_PLAYLIST tasks")

        try:
            # Handle both integer and string playlist IDs
            playlist_id_int = int(playlist_id)
        except (ValueError, TypeError) as e:
            raise TaskExecutionError(f"Invalid playlist_id format: {playlist_id}") from e

        # Get the playlist from database
        playlist = await self.playlist_repository.get_by_id(playlist_id_int)
        if not playlist:
            raise TaskExecutionError(f"Playlist not found: {playlist_id}")

        # Load playlist in player
        await self.player_service.load_playlist(playlist_id_int)

        # Set play mode if specified
        if play_mode in ["continuous", "loop", "loop_one", "random", "single"]:
            self.player_service.set_mode(play_mode)

        # Enable shuffle if requested
        if shuffle:
            self.player_service.set_shuffle(True)

        # Start playing
        await self.player_service.play()

        logger.info(f"Started playing playlist {playlist.name} via scheduled task")