"""Service for managing list positioning and reordering"""

from app import db
from app.models import List


class ListPositionService:
    """Service for handling list position management"""

    @staticmethod
    def reorder_lists(board_id: int, moved_list_id: int, new_position: float) -> None:
        """
        Reorder all lists in a board when one list is moved to a new position.

        Args:
            board_id: The ID of board containing lists
            moved_list_id: The ID of list being moved
            new_position: The new position for moved list
        """
        # Get all lists in board, ordered by their current position
        all_lists = List.query.filter_by(board_id=board_id).order_by(List.pos).all()

        # Find moved list in board
        moved_list = None
        other_lists = []

        for lst in all_lists:
            if lst.id == moved_list_id:
                moved_list = lst
            else:
                other_lists.append(lst)

        if not moved_list:
            return  # List not found in this board

        # Insert moved list at the new position
        other_lists.insert(int(new_position), moved_list)

        # Update positions for all lists to ensure unique, sequential positions
        for index, lst in enumerate(other_lists):
            lst.pos = float(index)

        db.session.commit()

    @staticmethod
    def get_next_position(board_id: int) -> float:
        """
        Get next available position in a board.

        Args:
            board_id: The ID of board

        Returns:
            The next available position (float)
        """
        last_list = (
            List.query.filter_by(board_id=board_id).order_by(List.pos.desc()).first()
        )

        return float(last_list.pos + 1) if last_list else 0.0

    @staticmethod
    def ensure_unique_positions(board_id: int) -> None:
        """
        Ensure all lists in a board have unique, sequential positions.
        Useful for data cleanup.

        Args:
            board_id: The ID of board to fix
        """
        lists = List.query.filter_by(board_id=board_id).order_by(List.pos).all()

        for index, lst in enumerate(lists):
            lst.pos = float(index)

        db.session.commit()