import copy
from canibal_state_model import State

class Transition(object):
    def __init__(self,initialState,misionarNumber,canibalNumber):
        self.initialState = None
        self.misionarNumber = misionarNumber
        self.canibalNumber = canibalNumber
        self.initialState = copy.copy(initialState)
        if self.initialState.boatPosition == 0:
            self.resultState = State(self.initialState.boatCapacity,1-self.initialState.boatPosition,
            self.initialState.misionarsLeft - misionarNumber, self.initialState.canibalsLeft - canibalNumber,
            self.initialState.misionarsRight + misionarNumber, self.initialState.canibalsRight + canibalNumber)
        else:
            self.resultState = State(self.initialState.boatCapacity,1-self.initialState.boatPosition,
            self.initialState.misionarsLeft + misionarNumber, self.initialState.canibalsLeft + canibalNumber,
            self.initialState.misionarsRight - misionarNumber, self.initialState.canibalsRight - canibalNumber)


    def isValidTransition(self):
        if self.misionarNumber + self.canibalNumber > self.resultState.boatCapacity:
            return False

        if self.resultState.misionarsLeft < 0 or self.resultState.misionarsRight < 0:
            return False

        if self.resultState.canibalsLeft < 0 or self.resultState.canibalsRight < 0:
            return False

        if self.resultState.misionarsLeft < self.resultState.canibalsLeft:
            return False

        if self.resultState.misionarsRight < self.resultState.canibalsRight:
            return False

        return True

    def getResultState(self):
        return self.resultState