"""Contains solver for solitaire"""
from typing import List, Iterator, Optional
from .board import Board
from . import board_actions
from .board_possibilities import possible_actions
from .board_actions import MoveAction


class ActionStack:
    iterator_stack: List[Iterator[board_actions.Action]]
    action_stack: List[Optional[board_actions.Action]]
    index_stack: List[int]
    state_stack: List[int]

    def __init__(self) -> None:
        self.iterator_stack = []
        self.index_stack = []
        self.action_stack = []
        self.state_stack = []

    def push(self, board: Board) -> None:
        self.iterator_stack.append(possible_actions(board))
        self.action_stack.append(None)
        self.index_stack.append(0)
        self.state_stack.append(board.state_identifier)

    def get(self) -> Optional[board_actions.Action]:
        try:
            self.action_stack[-1] = next(self.iterator_stack[-1])
        except StopIteration:
            return None
        self.index_stack[-1] += 1
        return self.action_stack[-1]

    def pop(self) -> None:
        self.action_stack.pop()
        self.iterator_stack.pop()
        self.index_stack.pop()
        self.state_stack.pop()

    def __len__(self) -> int:
        return len(self.index_stack)


def solve(board: Board) -> Iterator[List[board_actions.Action]]:
    """Solve a solitaire puzzle"""
    state_set = {board.state_identifier}
    stack = ActionStack()
    stack.push(board)

    while stack:
        if len(stack) == -1:
            stack.pop()
            stack.action_stack[-1].undo(board)
            assert (board.state_identifier
                    in state_set)

        assert (board.state_identifier ==
                stack.state_stack[-1])
        action = stack.get()

        if not action:
            stack.pop()
            stack.action_stack[-1].undo(board)
            assert (board.state_identifier
                    in state_set)
            continue

        if isinstance(action, MoveAction):
            drop = False
            for prev_action in stack.action_stack[-2:-21:-1]:
                if isinstance(prev_action, MoveAction):
                    if prev_action.cards == action.cards:
                        print("Dropping")
                        print(action)
                        print(prev_action)
                        drop = True
            if drop:
                continue

        action.apply(board)

        if board.solved():
            yield stack.action_stack

        if board.state_identifier in state_set:
            action.undo(board)
            assert board.state_identifier in state_set
            continue

        state_set.add(board.state_identifier)
        stack.push(board)