"""
MODULE:       r.agent.*
AUTHOR(S):    michael lustenberger inofix.ch
PURPOSE:      library file for the r.agent.* suite
COPYRIGHT:    (C) 2015 by Michael Lustenberger and the GRASS Development Team

              This program is free software under the GNU General Public
              License (>=v2). Read the file COPYING that comes with GRASS
              for details.
"""
#from random import choice, randint
from random import randint

class Agent(object):
    """
    Generic Agent class with limited capabilities, as a basis for
    child classes.
    """

    def __init__(self, timetolive, world, position=[]):
        """
        Create an Agent, an actor on playgrounds, living in a world
        @param int time to live
        @param World the agent knows the worlds he lives in
        @param list coordinate of the current position
        """
        self.ttl = timetolive
        self.world = world
        self.position = position
        self.knowscompass = False

    def setposition(self, position):
        """
        Tell the agent to stand still at a certain position
        @param list coordinate of the current position
        """
        if position and position != []:
            self.position[0] = position[0]
            self.position[1] = position[1]

    def getposition(self):
        """
        Ask the agent for its current position
        @return list coordinate of the current position
        """
#TODO not very meaningful yet..
        return self.position

    def randomposition(self, positions):
        """
        Pick a random position out of a list of positions
        @param positions list of possible positions
        @return position the decision for a position
        """
        return positions[randint(0, len(positions)-1)]

    def step(self):
        """
        Move to a neighbour position, as in making a single step
        @param list coordinates of a certain cell
        @param list coordinates of a certain cell
        """
        position = self.getposition()
        positions = self.world.getneighbourpositions(position)
        # positions are already shuffled
        self.setposition(positions[0])

    def age(self):
        """
        Let the agent grow older
        @return boolean whether agent is still alive
        """
        if self.ttl > 0:
            self.ttl -= 1
            return True
        else:
            self.snuffit()
            return False

    def snuffit(self):
        """to die peacefully and without pain"""
        self.world.kill(self)