AntiPlatka/src/main/java/ru/emotilt/antiplatka/poll/BotPoll.java

package ru.emotilt.antiplatka.poll;

import java.time.Duration;
import java.util.Date;
import java.util.Objects;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import org.jetbrains.annotations.Nullable;

import net.dv8tion.jda.api.entities.Member;
import net.dv8tion.jda.api.entities.Message;
import net.dv8tion.jda.api.entities.channel.middleman.MessageChannel;
import net.dv8tion.jda.api.entities.emoji.Emoji;
import net.dv8tion.jda.api.utils.messages.MessageCreateBuilder;
import net.dv8tion.jda.api.utils.messages.MessagePollBuilder;
import net.dv8tion.jda.api.utils.messages.MessagePollData;
import ru.emotilt.antiplatka.Bot;

public abstract class BotPoll {
    public final @Nullable Message message;
    // TODO: Create an abstraction for targets. This means that it can have any
    // targets except the user.
    public final Member targetUser;
    public final @Nullable MessageChannel channel;
    public final Date start;
    public final Duration voteDuration;

    public abstract void endVote();

    public abstract String getEndAnnouncementText(boolean success);

    @SuppressWarnings("method.invocation")
    public BotPoll(@Nullable Message message, Member targetUser, @Nullable MessageChannel channel, Date start, Duration voteDuration) {
        this.message = message;
        this.targetUser = targetUser;
        this.channel = channel;
        this.start = start;
        this.voteDuration = voteDuration;

        schedule(message);
    }

    /**
     * Queue to complete the poll.
     * This is required if the poll lasts less than 1 hour.
     * 
     * @param message A message containing a poll.
     */
    public void schedule(@Nullable Message message) {
        if (isShort()) {
            ExecutorService executorService = Executors.newSingleThreadExecutor();
            executorService.submit(() -> {
                try {
                    Thread.sleep(voteDuration.toMillis());
                } catch (InterruptedException e) {
                    throw new RuntimeException(e);
                }

                Objects.requireNonNull(message).endPoll().queue();
            });
            executorService.shutdown();
        }
    }

    protected boolean isShort() {
        // The Discord API does not allow polls that are less than 1 hour in length.
        return voteDuration.toMillis() < TimeUnit.HOURS.toMillis(1);
    }

    @SuppressWarnings("unused")
    public static abstract class Builder<T extends Builder<T>> {
        protected @Nullable Message message = null;
        protected Member targetUser;
        protected @Nullable MessageChannel channel = null;
        protected Date start = new Date();
        protected Duration voteDuration;

        protected abstract T self();

        public Builder(Member targetUser, Duration voteDuration) {
            this.targetUser = targetUser;
            this.voteDuration = voteDuration;
        }

        public T message(Message message) {
            this.message = message;
            return self();
        }

        public T targetUser(Member targetUser) {
            this.targetUser = targetUser;
            return self();
        }

        public T channel(MessageChannel channel) {
            this.channel = channel;
            return self();
        }

        public T start(Date start) {
            this.start = start;
            return self();
        }

        public T voteDuration(Duration voteDuration) {
            this.voteDuration = voteDuration;
            return self();
        }

        public MessageCreateBuilder buildMessage(String announcementText) {
            String title = announcementText + ". Порог голосования **%d%%**.";
            title = String.format(title, Bot.config.threshold);

            MessagePollData poll = new MessagePollBuilder("Голосование")
                    .addAnswer("Да", Emoji.fromUnicode("✅"))
                    .addAnswer("Нет", Emoji.fromUnicode("❌"))
                    .setDuration(
                            isShort() ? TimeUnit.HOURS.toMinutes(1)
                                    : voteDuration.toMinutes(),
                            TimeUnit.MINUTES)
                    .build();

            if (isShort()) {
                title += String.format(" Голосование закончится <t:%d:R>",
                        start.getTime() / 1000 + voteDuration.toSeconds());
            }

            return new MessageCreateBuilder().addContent(title).setPoll(poll);
        }

        protected boolean isShort() {
            // The Discord API does not allow polls that are less than 1 hour in length.
            return voteDuration.toMillis() < TimeUnit.HOURS.toMillis(1);
        }

        // Abstract build method to be implemented by subclasses
        public abstract BotPoll build();
    }
}