package uulm.teamname.marvelous.gamelibrary.gamelogic;

import uulm.teamname.marvelous.gamelibrary.events.Event;
import uulm.teamname.marvelous.gamelibrary.events.EventType;
import uulm.teamname.marvelous.gamelibrary.requests.Request;

import java.util.ArrayList;
import java.util.List;

/** Represents manager for a game state. */
class GameStateManager {
    /** The managed {@link GameState} */
    private final GameState state;

    /** The queue of {@link Event Events} to be applied during {@link Request} processing */
    private final ArrayList<Event> queue = new ArrayList<>();

    /**
     * Constructs a new {@link GameStateManager}.
     * @param state A reference to the state to be managed
     */
    public GameStateManager(GameState state) {
        this.state = state;
    }

    /**
     * Checks a list of {@link Request Requests} for validity and optionally produces resulting {@link Event Events}.
     * @param requests The requests to check
     * @param apply True if resulting events should be stored for later application
     * @return Whether the requests are valid
     */
    public boolean processRequests(ArrayList<Request> requests, boolean apply) {
        GameState snapshot = state.snapshot();

        for(Request request: requests) {
            if (GameLogic.checkRequest(snapshot, request)) {
                ArrayList<Event> result = GameLogic.executeRequest(snapshot, request);
                for(Event event: result) {
                    GameLogic.applyEvent(snapshot, event);
                }
                if(apply) {
                    queue.addAll(result);
                }
            }else {
                queue.clear();
                return false;
            }
        }

        return true;
    }

    /**
     * Applies an array of {@link Event Events} to the game state.
     * @param events The events to apply
     */
    public void applyEvents(Event[] events) {
        for(Event event: events) {
            GameLogic.applyEvent(state, event);
        }
    }

    /**
     * Applies an array of {@link Event Events} to the game state.
     * @param events The events to apply
     */
    public void applyEvents(List<Event> events) {
        for(Event event: events) {
            GameLogic.applyEvent(state, event);
        }
    }

    /**
     * Applies an {@link Event} to the game state.
     * @param event The event to apply
     */
    public void applyEvent(Event event) {
        GameLogic.applyEvent(state, event);
    }

    /**
     * Applies the result of the last processRequests call.
     * @return A list of applied events
     */
    public ArrayList<Event> apply() {
        for(Event event: queue) {
            GameLogic.applyEvent(state, event);
        }

        // i feel so smart for remembering this trick
        try {
            return new ArrayList<>(queue);
        }finally {
            queue.clear();
        }
    }

    /**
     * Handles events that happen after a turn phase.
     * @return The optionally resulting {@link Event Events}
     */
    public ArrayList<Event> checkPostPhase() {
        GameState snapshot = state.snapshot();
        ArrayList<Event> result = GameLogic.checkTurnEnd(snapshot);
        applyEvents(result);
        return result;
    }

    /**
     * Initializes and starts the game.
     * @param selectedCharacters1 The characters selected by player 1
     * @param selectedCharacters2 The characters selected by player 2
     * @return The resulting {@link Event Events}
     */
    public List<Event> startGame(List<Integer> selectedCharacters1, List<Integer> selectedCharacters2) {
        GameState snapshot = state.snapshot();

        ArrayList<Event> result = GameLogic.startGame(snapshot, selectedCharacters1, selectedCharacters2);
        applyEvents(result);

        snapshot = state.snapshot();

        ArrayList<Event> result2 = GameLogic.startRound(snapshot);
        applyEvents(result2);

        result.addAll(result2);

        return result;
    }

    /**
     * Forcefully ends the current turn.
     * @return The resulting {@link Event Events}
     */
    public ArrayList<Event> endTurn() {
        GameState snapshot = state.snapshot();
        ArrayList<Event> result = GameLogic.endTurn(snapshot);
        applyEvents(result);
        return result;
    }

    /**
     * Produces a {@link EventType#GamestateEvent} for the current {@link GameState}.
     * @return The resulting event
     */
    public Event getGameStateEvent() {
        return GameLogic.buildGameStateEvent(state);
    }
}