// vendingmachine.cc written by Andreas Bauer <baueran@in.tum.de>

#include <cstdlib>
#include <iostream>
#include "vendingmachine.hh"

using namespace std;

void (Vendingmachine :: *cur_state)  (void);   // Current state of the state machine.
void (Vendingmachine :: *transition) (void);   // Pointer to a transition function.

Vendingmachine :: Vendingmachine (void)
{  manual = true;  }

void Vendingmachine :: automatic (void)
{  manual = false;  }

// This function returns a pointer to a transition function depending
// on the user's input/action.

fn_ptr Vendingmachine :: action (void)
{
  int money;

  if (manual)
    {
      cout << "Insert either 5 or 10 cents: " << endl;
      cin >> money;
    }
  else
    {
      // Generate random money insertions.
      money = (1 + (int)(2.0 * rand () / (RAND_MAX + 1.0))) * 5;
      PRINTLN(money);
    }
  
  switch (money)
    {
    case 5:
      return &Vendingmachine :: t_5_cents;
      break;
    case 10:
      return &Vendingmachine :: t_10_cents;
      break;
    default:
      PRINTLN("Only 5 or 10 cents allowed.");
      exit (-1);
      break;
    }
}

// These functions tail call into the new state of the state machine,
// depending on the current state the machine's in.

void Vendingmachine :: t_5_cents (void)
{
  if (cur_state == &Vendingmachine :: s_zero)
    s_nickel ();
  else if (cur_state == &Vendingmachine :: s_nickel)
    s_dime ();
  else if (cur_state == &Vendingmachine :: s_dime)
    s_15_cents ();
  else if (cur_state == &Vendingmachine :: s_15_cents)
    s_20_cents ();
  else
    {
      PRINTLN("Insert only the correct amount of 5 and 10 cent coins.");
      exit (-1);
    }
}

void Vendingmachine :: t_10_cents (void)
{
  if (cur_state == &Vendingmachine :: s_zero)
    s_dime ();
  else if (cur_state == &Vendingmachine :: s_dime)
    s_20_cents ();
  else if (cur_state == &Vendingmachine :: s_nickel)
    s_15_cents ();
  else if (cur_state == &Vendingmachine :: s_15_cents)
    {
      PRINTLN("I don't give change.  Here's your entire money back.");
      s_zero ();
    }
  else
    {
      PRINTLN("Insert only the correct amount of 5 and 10 cent coins.");
      exit (-1);
    }
}

// The state functions of the state machine ask for user input and
// then call a transition function which does the mapping of state x
// input symbol x state.

void Vendingmachine :: s_zero (void)
{
  cur_state = &Vendingmachine :: s_zero;
  PRINTLN("You have not yet inserted any money.");
  transition = action ();
  (this->*transition) ();
}

void Vendingmachine :: s_nickel (void)
{
  cur_state = &Vendingmachine :: s_nickel;
  PRINTLN("You have inserted 5 cents.");
  transition = action ();
  (this->*transition) ();
}

void Vendingmachine :: s_dime (void)
{
  cur_state = &Vendingmachine :: s_dime;
  PRINTLN("You have inserted 10 cents.");
  transition = action ();
  (this->*transition) ();
}

void Vendingmachine :: s_15_cents (void)
{
  cur_state = &Vendingmachine :: s_15_cents;
  PRINTLN("You have inserted 15 cents.");
  transition = action ();
  (this->*transition) ();
}

void Vendingmachine :: s_20_cents (void)
{
  cur_state = &Vendingmachine :: s_20_cents;
  PRINTLN("You have inserted 20 cents. Here's your candy.");
  s_zero ();
}

// This is a simple, public start function.

void Vendingmachine :: start (void)
{
  PRINTLN("Hello! I'm your friendly candy machine.");
  s_zero ();
}