from zerolife import *

class Species ():
    def __init__(self, name):
        self.name = name
        self.color = None
        self.rules = []        

    def addRule(self, rule, index=None):
        '''Places a rule in the list in a user selected place. This is 
        given as an index.'''
        if index:
            self.rules.insert(rule, index)
        else:
           self.rules.append(rule)

    def removeRule(self, rule):
        '''Removes a rule from the list.'''
        try:
            self.rules.remove(rule)
        except Exception as e:
            pass
                   
    def next(self, board, coordinates):
        '''Examines each rule in sequence and returns the instruction for the
       first one that evaluates to true.
       If no rule evaluates to true, a stay instruction is returned.'''
        for r in rules:
            if r.holds(board, coordinates):
               return r.getInstructions(coordinates)
            '''Calls Instruction constructor to make a new instruction object
               with the parameters that result in stay.'''
        return [Instruction.Instruction(direction.C, self, coordinates)]