// Copyright 2010 Christophe Henry
// henry UNDERSCORE christophe AT hotmail DOT com
// This is an extended version of the state machine available in the boost::mpl
// library
// Distributed under the same license as the original.
// Copyright for the original version:
// Copyright 2005 David Abrahams and Aleksey Gurtovoy. Distributed
// under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)

#include <chrono>
#include <iostream>
#include <thread>
// back-end
#include <boost/msm/back/state_machine.hpp>
// front-end
#include <boost/msm/front/state_machine_def.hpp>
// functors
#include <boost/msm/front/euml/common.hpp>
#include <boost/msm/front/functor_row.hpp>

namespace msm = boost::msm;
namespace mpl = boost::mpl;
using namespace boost::msm::front;

namespace {
// events
struct event1 {};

// front-end: define the FSM structure
struct my_machine_ : public msm::front::state_machine_def<my_machine_> {
  // The list of FSM states
  struct State1 : public msm::front::state<> {
    // every (optional) entry/exit methods get the event passed.
    template <class Event, class FSM> void on_entry(Event const &, FSM &) {
      std::cout << "entering: State1" << std::endl;
    }
    template <class Event, class FSM> void on_exit(Event const &, FSM &) {
      std::cout << "leaving: State1" << std::endl;
    }
  };
  struct State2 : public msm::front::state<> {
    template <class Event, class FSM> void on_entry(Event const &, FSM &) {
      std::cout << "entering: State2" << std::endl;
    }
    template <class Event, class FSM> void on_exit(Event const &, FSM &) {
      std::cout << "leaving: State2" << std::endl;
    }
  };

  struct State3 : public msm::front::state<> {
    // when stopped, the CD is loaded
    template <class Event, class FSM> void on_entry(Event const &, FSM &) {
      std::cout << "entering: State3" << std::endl;
    }
    template <class Event, class FSM> void on_exit(Event const &, FSM &) {
      std::cout << "leaving: State3" << std::endl;
    }
  };

  struct State4 : public msm::front::state<> {
    template <class Event, class FSM> void on_entry(Event const &, FSM &) {
      std::cout << "entering: State4" << std::endl;
    }
    template <class Event, class FSM> void on_exit(Event const &, FSM &) {
      std::cout << "leaving: State4" << std::endl;
    }
  };

  // the initial state of the player SM. Must be defined
  typedef State1 initial_state;

  // transition actions
  struct State2ToState3 {
    template <class EVT, class FSM, class SourceState, class TargetState>
    void operator()(EVT const &, FSM &, SourceState &, TargetState &) {
      std::cout << "my_machine::State2ToState3" << std::endl;
    }
  };
  struct State3ToState4 {
    template <class EVT, class FSM, class SourceState, class TargetState>
    void operator()(EVT const &, FSM &, SourceState &, TargetState &) {
      std::cout << "my_machine::State3ToState4" << std::endl;
    }
  };

  struct BlockingCall {
    template <class EVT, class FSM, class SourceState, class TargetState>
    void operator()(EVT const &, FSM &, SourceState &, TargetState &) {
      std::cout << "my_machine::Waiting for a thing to happen..." << std::endl;
      // Pretend I'm actually waiting for something
      std::this_thread::sleep_for(std::chrono::milliseconds(100));
      std::cout << "my_machine::OMG the the thing happened!" << std::endl;
    }
  };

  // guard conditions
  struct always_true {
    template <class EVT, class FSM, class SourceState, class TargetState>
    bool operator()(EVT const &evt, FSM &fsm, SourceState &src,
                    TargetState &tgt) {
      std::cout << "always_true" << std::endl;
      return true;
    }
  };
  struct always_false {
    template <class EVT, class FSM, class SourceState, class TargetState>
    bool operator()(EVT const &evt, FSM &fsm, SourceState &src,
                    TargetState &tgt) {
      std::cout << "always_false" << std::endl;
      return true;
    }
  };

  typedef my_machine_ p; // makes transition table cleaner

  // Transition table for player
  // clang-format off
        struct transition_table : mpl::vector<
            //    Start     Event         Next      Action               Guard
            //  +---------+-------------+---------+---------------------+----------------------+
            Row < State1  , none        , State2                                               >,
            Row < State2  , none        , State3  , State2ToState3                             >,
            Row < State3  , none        , State4  , none                , always_false         >,
            //  +---------+-------------+---------+---------------------+----------------------+
            Row < State3  , none        , State4  , State3ToState4      , always_true          >,
            Row < State4  , none        , State1                                               >
            //  +---------+-------------+---------+---------------------+----------------------+
        > {};
  // clang-format on
  // Replaces the default no-transition response.
  template <class FSM, class Event>
  void no_transition(Event const &e, FSM &, int state) {
    std::cout << "no transition from state " << state << " on event "
              << typeid(e).name() << std::endl;
  }
};
// Pick a back-end
typedef msm::back::state_machine<my_machine_> my_machine;

//
// Testing utilities.
//
static char const *const state_names[] = {"State1", "State2", "State3",
                                          "State4"};
void pstate(my_machine const &p) {
  std::cout << " -> " << state_names[p.current_state()[0]] << std::endl;
}

void test() {
  my_machine p;

  // needed to start the highest-level SM. This will call on_entry and mark the
  // start of the SM
  // in this case it will also immediately trigger all anonymous transitions
  p.start();
  // this event will bring us back to the initial state and thus, a new "loop"
  // will be started
  p.process_event(event1());
}
}

int main() {
  test();
  return 0;
}