StateMachine.h

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// SPDX-License-Identifier: Apache-2.0
// Copyright 2022 Stéphane Caron
 
#pragma once
 
#include "vulp/spine/AgentInterface.h"
 
namespace vulp::spine {
 
constexpr unsigned kNbStopCycles = 5;
 
enum class State : uint32_t {
  kSendStops = 0,
  kReset = 1,
  kIdle = 2,
  kObserve = 3,
  kAct = 4,
  kShutdown = 5,
  kOver = 6
};
 
enum class Event : uint32_t {
  kCycleBeginning = 0,
  kCycleEnd = 1,
  kInterrupt = 2,
};
 
constexpr const char* state_name(const State& state) noexcept {
  switch (state) {
    case State::kSendStops:
      return "State::kSendStops";
    case State::kReset:
      return "State::kReset";
    case State::kIdle:
      return "State::kIdle";
    case State::kObserve:
      return "State::kObserve";
    case State::kAct:
      return "State::kAct";
    case State::kShutdown:
      return "State::kShutdown";
    case State::kOver:
      return "State::kOver";
    default:
      break;
  }
  return "?";
}
 
class StateMachine {
 public:
  explicit StateMachine(AgentInterface& interface) noexcept;
 
  void process_event(const Event& event) noexcept;
 
  const State& state() const noexcept { return state_; }
 
  bool is_over_after_this_cycle() const noexcept {
    return (state_ == State::kShutdown && stop_cycles_ + 1u == kNbStopCycles);
  }
 
 private:
  void enter_state(const State& next_state) noexcept;
 
  void process_cycle_beginning();
 
  void process_cycle_end();
 
 private:
  AgentInterface& interface_;
 
  State state_;
 
  unsigned stop_cycles_;
};
 
}  // namespace vulp::spine