javajeu/Jeu.java

import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
import java.util.regex.Pattern;
import java.util.stream.Stream;

public class Jeu {

    static interface ThenThat {
        public void run(Player player);
    }

    static class ChainAction implements Action {
        final Action ifthis;
        ThenThat thenthat;
  
        public ChainAction(Action ifthis) {
            this.ifthis = ifthis;
        }

        public ChainAction then(ThenThat thenthat) {
            this.thenthat = thenthat;
            return new ChainAction(this);
        }

        @Override
        public boolean match(String input, Player player) {
            if (ifthis.match(input, player)) {
                if (thenthat != null) {
                    thenthat.run(player);
                }
                return true;
            }
            return false;
        }
    }

    static ThenThat say(String reaction) {
        return p -> System.out.println(reaction);
    }

    static ChainAction getRegexpMatcher(String regexp) {
        Pattern p = Pattern.compile(regexp);
        return new ChainAction((input, player) -> {
            return p.matcher(input).matches();
        });
    }

    static ChainAction getVOMatcher(String verb, String object) {
        return getRegexpMatcher(verb + "( the)? " + object);
    }

    static ChainAction getVOReaction(String verb, String object, String reaction) {
        return getVOMatcher(verb, object).then(say(reaction));
    }

    static class StateMachineAction implements Action {
        final Action matcher;
        final Map<Integer, ThenThat> reactions = new HashMap<>();
        public int state = 0;

        public StateMachineAction(Action matcher) {
            this.matcher = matcher;
        }

        public StateMachineAction when(int state, ThenThat thenthat) {
            this.reactions.put(state, thenthat);
            return this;
        }

        @Override
        public boolean match(String input, Player player) {
            if (!this.matcher.match(input, player)) {
                return false;
            }
            if (this.reactions.containsKey(this.state)) {
                this.reactions.get(this.state).run(player);
            }
            return true;
        }
    }

    static class OnceAction extends StateMachineAction {
        public OnceAction(Action matcher) {
            super(matcher);
        }

        public OnceAction atFirst(ThenThat thenThat) {
            this.when(0, player -> {
                thenThat.run(player);
                this.state = 1;
            });
            return this;
        }

        public OnceAction thenLater(ThenThat thenThat) {
            this.when(1, thenThat);
            return this;
        }
    }

    static Place makeWorld() {
        Place startingPoint = new Place("Some sort of place");
        startingPoint.description = "You find yourself in MadVillain's lair.\n" +
                "It's reaaally dark here. You can feel a light switch on the wall on your right.";

        Place hallWay = new Place("Hallway");
        hallWay.description = "This is the hallway that you came from. You don't spend much time looking at it\n" +
                "so I won't spend much time describing it. It leads *outside*. Fresh air.";

        Place outside = new Place("outside");
        outside.description = "The great outdoors. I mean, it's still the city. Dull gray and mornful city.\n" +
                "But it's also outdoors. And great, in a way. You can go anywhere. If you can.";
        outside.actions.add(getVOReaction("go to", "hallway", "There's nothing to do there anymore."));

        hallWay.actions.add(getRegexpMatcher("(go|get) (out|outside)").then(player -> {
            System.out.println("The bright light of an overcast mid-morning in the city blinds you for a few seconds.\n" +
            "It's not actually very bright. The smog absorbs a sizeable portion of the meager apricity.");
            player.place = outside;
        }));

        final Action takeNotebook = new OnceAction(getVOMatcher("take", "notebook"))
                .atFirst(player -> {
                    System.out.println("You reach out and take the notebook. It's not very clean.");
                    final Item notebook = new Item("notebook");
                    final Action read = new OnceAction(getVOMatcher("read", "notebook"))
                            .atFirst(say("It's full of gibberish and satanic doodles. You feel sullied."))
                            .thenLater(say("No way you open this book again."));
                    notebook.action = read;
                    player.items.add(notebook);
                    startingPoint.description = "An extremely banal room. There's nothing here.\n" +
                            "I mean there is NOTHING here.\n" +
                            "Except the door behind you. You know, the DOOR.";
                }).thenLater(say("It's already in your pocket!"));

        final Action openDoor = getVOMatcher("open", "door").then(player -> {
            if (player.items.stream().anyMatch(i -> i.name.equals("notebook"))) {
                System.out.println("Having spent enough time in this sordid place, you turn on your heels and head out.");
                player.place = hallWay;
            } else {
                System.out.println("Ahem. I said there is a NOTEBOOK here.");
            }
        });

        final Action flipSwitch = new OnceAction(
                getRegexpMatcher("(turn ((the )?lights? on|on( the)? lights?)|flip( the)?( light)? switch)"))
                .atFirst(player -> {
                    System.out.println("*clic*");
                    startingPoint.description = "An extremely banal room. There's nothing here.\n" +
                            "I mean, there's nothing here, aside from a weathered notebook.\n" +
                            "There's also a door, just behind you.";
                    startingPoint.actions.add(takeNotebook);
                    startingPoint.actions.add(openDoor);
                })
                .thenLater(say("It's an LED bulb, so it's ok to leave the light on."));

        startingPoint.actions.add(flipSwitch);

        return startingPoint;
    }

    static boolean match(Action[] actions, String input, Player player) {
        for (final Action action : actions) {
            if (action.match(input, player)) {
                return true;
            }
        }
        return false;
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("What is your name?");

        String name = scanner.nextLine();

        Player player = new Player(name);
        player.place = makeWorld();

        System.out.println("Howdy there, Detective " + name+ ".");

        System.out.println(player.place.description);

        while (true) {
            System.out.print("> ");
            String line = scanner.nextLine();

            if (line.startsWith("bye")) {
                break;
            }

            final Action look = getRegexpMatcher("look( (here|around))?")
                    .then(p -> System.out.println(p.place.description));
            Action[] actions = Stream.concat(
                    Stream.concat(
                            player.place.actions.stream(),
                            player.items.stream().map(i -> i.action)),
                    Arrays.stream(new Action[] { look })).toArray(Action[]::new);
            if (!match(actions, line, player)) {
                System.out.println("Wot?");
            }
        }

        scanner.close();
    }
}