initial bot and in-memory storage

src/main/java/me/youhavetrouble/inviter/DiscordInvite.java

@@ -0,0 +1,28 @@
+package me.youhavetrouble.inviter;
+
+public record DiscordInvite(
+        String code,
+        Long guildId,
+        Long expiresAt
+) {
+
+    public DiscordInvite {
+        if (code == null) {
+            throw new IllegalArgumentException("Code cannot be null");
+        }
+        if (guildId == null || guildId <= 0) {
+            throw new IllegalArgumentException("Guild ID must not be null nor be a negative number");
+        }
+    }
+
+    /**
+     * Checks if the invite is expired.
+     * The invite is considered expired if the current time is more than 5 seconds before the expiration time.
+     *
+     * @return true if the invite is expired, false otherwise
+     */
+    public boolean isExpired() {
+        return System.currentTimeMillis() + 5000 > expiresAt;
+    }
+
+}

src/main/java/me/youhavetrouble/inviter/Main.java

@@ -0,0 +1,49 @@
+package me.youhavetrouble.inviter;
+
+import me.youhavetrouble.inviter.storage.MemoryStorage;
+import me.youhavetrouble.inviter.storage.Storage;
+import net.dv8tion.jda.api.JDA;
+import net.dv8tion.jda.api.JDABuilder;
+import net.dv8tion.jda.api.requests.GatewayIntent;
+import net.dv8tion.jda.api.utils.cache.CacheFlag;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Set;
+
+public class Main {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger("Inviter");
+
+    private static JDA jda;
+
+    private static Storage storage;
+
+    public static void main(String[] args) throws InterruptedException {
+
+        String token = System.getenv("DISCORD_TOKEN");
+
+        jda = JDABuilder.create(
+                        token,
+                        Set.of(GatewayIntent.GUILD_INVITES)
+                )
+                .disableCache(
+                        CacheFlag.ACTIVITY,
+                        CacheFlag.VOICE_STATE,
+                        CacheFlag.EMOJI,
+                        CacheFlag.STICKER,
+                        CacheFlag.CLIENT_STATUS,
+                        CacheFlag.ONLINE_STATUS,
+                        CacheFlag.SCHEDULED_EVENTS
+                )
+                .build();
+
+        jda.awaitReady();
+
+        storage = new MemoryStorage(jda);
+
+        LOGGER.info("Welcome to the Inviter Application!");
+
+    }
+
+}

src/main/java/me/youhavetrouble/inviter/storage/MemoryStorage.java

@@ -0,0 +1,75 @@
+package me.youhavetrouble.inviter.storage;
+
+import com.github.benmanes.caffeine.cache.Cache;
+import com.github.benmanes.caffeine.cache.Caffeine;
+import me.youhavetrouble.inviter.DiscordInvite;
+import net.dv8tion.jda.api.JDA;
+import net.dv8tion.jda.api.entities.Guild;
+import net.dv8tion.jda.api.entities.Invite;
+import net.dv8tion.jda.api.entities.channel.unions.DefaultGuildChannelUnion;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.time.Duration;
+import java.time.temporal.ChronoUnit;
+
+public class MemoryStorage implements Storage {
+
+    private final Cache<String, DiscordInvite> cache = Caffeine.newBuilder()
+            .expireAfterWrite(Duration.of(60, ChronoUnit.SECONDS))
+            .build();
+
+    private final JDA jda;
+
+    public MemoryStorage(JDA jda) {
+        this.jda = jda;
+    }
+
+
+    @Nullable
+    @Override
+    public DiscordInvite getInvite(long guildId) {
+        DiscordInvite discordInvite = cache.getIfPresent(String.valueOf(guildId));
+        if (discordInvite == null || discordInvite.isExpired()) {
+            Guild guild = jda.getGuildById(guildId);
+            if (guild == null) {
+                return null; // Guild not found
+            }
+            DefaultGuildChannelUnion defaultChannel = guild.getDefaultChannel();
+            if (defaultChannel == null) {
+                return null; // No default channel found
+            }
+            Invite invite = defaultChannel.createInvite()
+                    .setMaxAge(60) // Set the invite to expire after 60 seconds
+                    .complete();
+            if (invite == null) return null; // Failed to create invite
+            discordInvite = new DiscordInvite(
+                    invite.getCode(),
+                    guild.getIdLong(),
+                    invite.getTimeCreated().toEpochSecond()
+            );
+        }
+        return discordInvite;
+    }
+
+    @NotNull
+    @Override
+    public DiscordInvite saveInvite(Invite invite) {
+
+        if (invite == null) {
+            throw new IllegalArgumentException("Invite cannot be null");
+        }
+        if (invite.getGuild() == null) {
+            throw new IllegalArgumentException("Invite must be associated with a guild");
+        }
+
+        DiscordInvite discordInvite = new DiscordInvite(
+                invite.getCode(),
+                invite.getGuild().getIdLong(),
+                invite.getTimeCreated().toEpochSecond()
+        );
+
+        cache.put(invite.getGuild().getId(), discordInvite);
+        return discordInvite;
+    }
+}

src/main/java/me/youhavetrouble/inviter/storage/Storage.java

@@ -0,0 +1,19 @@
+package me.youhavetrouble.inviter.storage;
+
+import me.youhavetrouble.inviter.DiscordInvite;
+import net.dv8tion.jda.api.entities.Invite;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+public interface Storage {
+
+    @Nullable DiscordInvite getInvite(long guildId);
+
+    /**
+     * Saves the invite to the storage and returns the saved invite.
+     * @param invite JDA invite object to save
+     * @return the saved DiscordInvite object
+     */
+    @NotNull DiscordInvite saveInvite(Invite invite);
+
+}

src/main/resources/log4j2.xml

@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<Configuration name="Console">
+
+    <Properties>
+        <Property name="LOG_PATTERN">[%d{yyyy-MM-dd HH:mm:ss}] [%t/%p]: %msg%n</Property>
+    </Properties>
+
+    <Appenders>
+
+        <Console name="ConsoleTerminal" target="SYSTEM_OUT" follow="true">
+            <PatternLayout pattern="[%d{HH:mm:ss}] [%t/%p]: %msg%n"/>
+        </Console>
+
+        <RollingRandomAccessFile name="File" fileName="logs/latest.log" filePattern="logs/%d{yyyy-MM-dd}-%i.log.gz" immediateFlush="false">
+            <PatternLayout pattern="[%d{yyyy-MM-dd HH:mm:ss}] [%t/%p]: %msg%n"/>
+            <Policies>
+                <TimeBasedTriggeringPolicy/>
+                <OnStartupTriggeringPolicy/>
+            </Policies>
+        </RollingRandomAccessFile>
+    </Appenders>
+
+    <Loggers>
+        <Root level="INFO">
+            <AppenderRef ref="ConsoleTerminal"/>
+            <AppenderRef ref="File"/>
+        </Root>
+    </Loggers>
+</Configuration>