michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: package org.mozilla.gecko.fxa.login;
michael@0: 
michael@0: import java.security.NoSuchAlgorithmException;
michael@0: import java.util.HashSet;
michael@0: import java.util.Set;
michael@0: 
michael@0: import org.mozilla.gecko.background.fxa.FxAccountClient;
michael@0: import org.mozilla.gecko.browserid.BrowserIDKeyPair;
michael@0: import org.mozilla.gecko.fxa.login.FxAccountLoginTransition.Transition;
michael@0: import org.mozilla.gecko.fxa.login.State.StateLabel;
michael@0: 
michael@0: public class FxAccountLoginStateMachine {
michael@0:   public static final String LOG_TAG = FxAccountLoginStateMachine.class.getSimpleName();
michael@0: 
michael@0:   public interface LoginStateMachineDelegate {
michael@0:     public FxAccountClient getClient();
michael@0:     public long getCertificateDurationInMilliseconds();
michael@0:     public long getAssertionDurationInMilliseconds();
michael@0:     public void handleTransition(Transition transition, State state);
michael@0:     public void handleFinal(State state);
michael@0:     public BrowserIDKeyPair generateKeyPair() throws NoSuchAlgorithmException;
michael@0:   }
michael@0: 
michael@0:   public static class ExecuteDelegate {
michael@0:     protected final LoginStateMachineDelegate delegate;
michael@0:     protected final StateLabel desiredStateLabel;
michael@0:     // It's as difficult to detect arbitrary cycles as repeated states.
michael@0:     protected final Set<StateLabel> stateLabelsSeen = new HashSet<StateLabel>();
michael@0: 
michael@0:     protected ExecuteDelegate(StateLabel initialStateLabel, StateLabel desiredStateLabel, LoginStateMachineDelegate delegate) {
michael@0:       this.delegate = delegate;
michael@0:       this.desiredStateLabel = desiredStateLabel;
michael@0:       this.stateLabelsSeen.add(initialStateLabel);
michael@0:     }
michael@0: 
michael@0:     public FxAccountClient getClient() {
michael@0:       return delegate.getClient();
michael@0:     }
michael@0: 
michael@0:     public long getCertificateDurationInMilliseconds() {
michael@0:       return delegate.getCertificateDurationInMilliseconds();
michael@0:     }
michael@0: 
michael@0:     public long getAssertionDurationInMilliseconds() {
michael@0:       return delegate.getAssertionDurationInMilliseconds();
michael@0:     }
michael@0: 
michael@0:     public BrowserIDKeyPair generateKeyPair() throws NoSuchAlgorithmException {
michael@0:       return delegate.generateKeyPair();
michael@0:     }
michael@0: 
michael@0:     public void handleTransition(Transition transition, State state) {
michael@0:       // Always trigger the transition callback.
michael@0:       delegate.handleTransition(transition, state);
michael@0: 
michael@0:       // Possibly trigger the final callback. We trigger if we're at our desired
michael@0:       // state, or if we've seen this state before.
michael@0:       StateLabel stateLabel = state.getStateLabel();
michael@0:       if (stateLabel == desiredStateLabel || stateLabelsSeen.contains(stateLabel)) {
michael@0:         delegate.handleFinal(state);
michael@0:         return;
michael@0:       }
michael@0: 
michael@0:       // If this wasn't the last state, leave a bread crumb and move on to the
michael@0:       // next state.
michael@0:       stateLabelsSeen.add(stateLabel);
michael@0:       state.execute(this);
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   public void advance(State initialState, final StateLabel desiredStateLabel, final LoginStateMachineDelegate delegate) {
michael@0:     if (initialState.getStateLabel() == desiredStateLabel) {
michael@0:       // We're already where we want to be!
michael@0:       delegate.handleFinal(initialState);
michael@0:       return;
michael@0:     }
michael@0:     ExecuteDelegate executeDelegate = new ExecuteDelegate(initialState.getStateLabel(), desiredStateLabel, delegate);
michael@0:     initialState.execute(executeDelegate);
michael@0:   }
michael@0: }