class States:
  UNDEFINED = "UNDEFINED"
  STOP = "STOP"
  ACCEPT = "ACCEPT"
  
  S = "S"
  SC1 = "SC1"
  SC2 = "SC2"
  
  

# TM akceptująca ciąg gdy po raz trzeci odczyta symbol c (zbiór dopuszczalnych symboli to {a, b, c}).
tansitionTable = [
  {"in": {"currentState": States.S, "currentSymbol": "c"},
    "out": {"newState": States.SC1, "newSymbol": "C", "headMove": "R"}},
  {"in": {"currentState": States.SC1, "currentSymbol": "c"},
    "out": {"newState": States.SC2, "newSymbol": "C", "headMove": "R"}},
  {"in": {"currentState": States.SC2, "currentSymbol": "c"},
    "out": {"newState": States.ACCEPT, "newSymbol": "C", "headMove": "-"}},
    
  {"in": {"currentState": States.S, "currentSymbol": None},
    "out": {"newState": States.S, "newSymbol": "-", "headMove": "R"}},
  {"in": {"currentState": States.SC1, "currentSymbol": None},
    "out": {"newState": States.SC1, "newSymbol": "-", "headMove": "R"}},
  {"in": {"currentState": States.SC2, "currentSymbol": None},
    "out": {"newState": States.SC2, "newSymbol": "-", "headMove": "R"}}
]


class TM:
  tansitionTable = None
  currentState = None
  stopState = None
  tape = None
  headPosition = None

  def __init__(self, *, initState, stopState, tansitionTable, tape, headPosition):
    self.currentState = initState
    self.stopState = stopState
    self.tansitionTable = tansitionTable
    self.headPosition = headPosition
    self.tape = {}
    
    for idx, character in enumerate(tape):
      self.tape[idx] = character
      
  def printTape(self):
    for key, value in sorted(self.tape.items()):
      if key == self.headPosition:
        print("[{0}]".format(value), end="")
      else:
        print(value, end="")

  def run(self):
    while (self.currentState not in self.stopState):
      self.printTape()
      noTransition = True
      
      symbol = self.tape[self.headPosition]

      for action in self.tansitionTable:
        if ((self.currentState == action["in"]["currentState"]
             and symbol == action["in"]["currentSymbol"])
            or
            (self.currentState == action["in"]["currentState"]
             and action["in"]["currentSymbol"] == None)):
          print("({0}, {1}) => ({2}, {3}, {4})".format(self.currentState,
                                                       symbol,
                                                       action["out"]["newState"],
                                                       action["out"]["newSymbol"],
                                                       action["out"]["headMove"]))
          self.currentState = action["out"]["newState"]
          symbol = action["out"]["newSymbol"]
          move = action["out"]["headMove"]
          
          if symbol != "-":
            self.tape[self.headPosition] = symbol
          if move == "R":
            self.headPosition += 1
          elif move == "L":
            self.headPosition -= 1
          
          noTransition = False
          break
          
      if noTransition:
        print("No transition for (state,action) = ({0}, {1})".format(self.currentState, symbol))
        break
        
      input("Press ENTER")
      
    self.printTape()
    print()


def main():
  initState = States.S
  stopState = [States.STOP, States.ACCEPT]
  tape = "abcabcabcabcabc"
  headPosition = 3 
  tm = TM(initState = initState,
          stopState = stopState,
          tansitionTable = tansitionTable,
          tape = tape,
          headPosition = headPosition)
  tm.run()

if (__name__ == '__main__'):
  main()