import pytest

from ...tokens.doc import Doc
from ...vocab import Vocab
from ...syntax.stateclass import StateClass


def get_doc(words, vocab=None):
    if vocab is None:
        vocab = Vocab()
    return Doc(vocab, words=list(words))

def test_push():
    '''state.push_stack() should take the first word in the queue (aka buffer)
    and put it on the stack, popping that word from the queue.'''
    doc = get_doc('abcd')
    state = StateClass(doc)
    assert state.get_B(0) == 0
    state.push_stack()
    assert state.get_B(0) == 1

def test_pop():
    '''state.pop_stack() should remove the top word from the stack.'''
    doc = get_doc('abcd')
    state = StateClass(doc)
    assert state.get_B(0) == 0
    state.push_stack()
    state.push_stack()
    assert state.get_S(0) == 1
    assert state.get_S(1) == 0
    state.pop_stack()
    assert state.get_S(0) == 0


def test_split():
    '''state.split_token should take the ith word of the buffer, and split it
    into n+1 pieces. n is 0-indexed, i.e. split(i, 0) is a noop, and split(i, 1)
    creates 1 new token.'''
    doc = get_doc('abcd')
    state = StateClass(doc, max_split=3)
    assert state.queue == [0, 1, 2, 3]
    state.split_token(1, 2)
    assert state.queue == [0, 1, 1*4+1, 2*4+1, 2, 3]