#include "state_machine.h"

namespace vdi {

const char* stateToString(State s) {
    switch (s) {
        case State::kBoot:          return "BOOT";
        case State::kConfig:        return "CONFIG";
        case State::kAuthenticating: return "AUTHENTICATING";
        case State::kDesktopList:   return "DESKTOP_LIST";
        case State::kConnecting:    return "CONNECTING";
        case State::kSession:       return "SESSION";
        case State::kReconnect:     return "RECONNECT";
        case State::kError:         return "ERROR";
    }
    return "UNKNOWN";
}

StateMachine::StateMachine(StateListener listener) : listener_(std::move(listener)) {}

bool StateMachine::isLegalTransition(State from, State to) {
    switch (from) {
        case State::kBoot:
            return to == State::kConfig || to == State::kError;
        case State::kConfig:
            return to == State::kAuthenticating || to == State::kConnecting ||
                   to == State::kError;
        case State::kAuthenticating:
            return to == State::kDesktopList || to == State::kConfig || to == State::kError;
        case State::kDesktopList:
            return to == State::kConnecting || to == State::kConfig || to == State::kError;
        case State::kConnecting:
            return to == State::kSession || to == State::kReconnect ||
                   to == State::kDesktopList || to == State::kError;
        case State::kSession:
            return to == State::kReconnect || to == State::kDesktopList ||
                   to == State::kConfig || to == State::kError;
        case State::kReconnect:
            return to == State::kConnecting || to == State::kDesktopList ||
                   to == State::kConfig || to == State::kError;
        case State::kError:
            return to == State::kConfig || to == State::kDesktopList ||
                   to == State::kConnecting;
    }
    return false;
}

bool StateMachine::transitionTo(State next, const QString& detail) {
    if (!isLegalTransition(current_, next)) {
        return false;
    }
    State from = current_;
    current_ = next;
    if (listener_) {
        listener_(from, next, detail);
    }
    return true;
}

bool StateMachine::canConnect() const {
    return current_ == State::kDesktopList || current_ == State::kConfig ||
           current_ == State::kReconnect || current_ == State::kError;
}

bool StateMachine::canDisconnect() const {
    return current_ == State::kSession || current_ == State::kConnecting;
}

bool StateMachine::canRetry() const {
    return current_ == State::kReconnect || current_ == State::kError;
}

}  // namespace vdi