"""
The "travel from home to the park" example from my lectures.
Author: Dana Nau <nau@cs.umd.edu>, May 31, 2013
This file should work correctly in both Python 2.7 and Python 3.2.
"""
from pyhop import hop


def taxi_rate(dist):
    return (1.5 + 0.5 * dist)

def walk(state,a,x,y):
    if state.loc[a] == x:
        state.loc[a] = y
        return state
    else: return False

def call_taxi(state,a,x):
    state.loc['taxi'] = x
    return state

def ride_taxi(state,a,x,y):
    if state.loc['taxi']==x and state.loc[a]==x:
        state.loc['taxi'] = y
        state.loc[a] = y
        state.owe[a] = taxi_rate(state.dist[x][y])
        return state
    else: return False

def pay_driver(state,a):
    if state.cash[a] >= state.owe[a]:
        state.cash[a] = state.cash[a] - state.owe[a]
        state.owe[a] = 0
        return state
    else: return False

hop.declare_operators(walk, call_taxi, ride_taxi, pay_driver)
print('')
hop.print_operators(hop.get_operators())

def travel_by_foot(state,a,x,y):
    if state.dist[x][y] <= 2:
        return [('walk',a,x,y)]
    return False

def travel_by_taxi(state,a,x,y):
    if state.cash[a] >= taxi_rate(state.dist[x][y]):
        return [('call_taxi',a,x), ('ride_taxi',a,x,y), ('pay_driver',a)]
    return False

hop.declare_methods('travel',travel_by_foot,travel_by_taxi)
print('')
hop.print_methods(hop.get_methods())

state1 = hop.State('state1')
state1.loc = {'me':'home'}
state1.cash = {'me':20}
state1.owe = {'me':0}
state1.dist = {'home':{'park':8}, 'park':{'home':8}}

print("""
********************************************************************************
Call hop.plan(state1,[('travel','me','home','park')]) with different verbosity levels
********************************************************************************
""")

print("- If verbose=0 (the default), Pyhop returns the solution but prints nothing.\n")
hop.plan(state1,
         [('travel','me','home','park')],
         hop.get_operators(),
         hop.get_methods())

print('- If verbose=1, Pyhop prints the problem and solution, and returns the solution:')
hop.plan(state1,
         [('travel','me','home','park')],
         hop.get_operators(),
         hop.get_methods(),
         verbose=1)

print('- If verbose=2, Pyhop also prints a note at each recursive call:')
hop.plan(state1,
         [('travel','me','home','park')],
         hop.get_operators(),
         hop.get_methods(),
         verbose=2)

print('- If verbose=3, Pyhop also prints the intermediate states:')
hop.plan(state1,
         [('travel','me','home','park')],
         hop.get_operators(),
         hop.get_methods(),
         verbose=3)