Add Discord bot support for sending appeals to specified channels and integrate with appeal flow

discord/src/main/java/com/alttd/webinterface/bot/DiscordBotInstance.java

@@ -1,22 +1,34 @@
 package com.alttd.webinterface.bot;
 
 import lombok.Getter;
+import lombok.extern.slf4j.Slf4j;
 import net.dv8tion.jda.api.JDA;
 import net.dv8tion.jda.api.JDABuilder;
 import net.dv8tion.jda.api.requests.GatewayIntent;
 
+@Slf4j
 public class DiscordBotInstance {
 
     @Getter
     private JDA jda;
+    private volatile boolean ready = false;
 
-    public void start(String token) {
+    public synchronized void start(String token) {
+        if (jda != null) {
+            return;
+        }
         jda = JDABuilder.createDefault(token,
                 GatewayIntent.GUILD_MEMBERS,
                 GatewayIntent.GUILD_PRESENCES,
                 GatewayIntent.GUILD_MESSAGES,
                 GatewayIntent.MESSAGE_CONTENT)
-                        .build();
+                .addEventListeners(new ReadyListener(() -> {
+                    ready = true;
+                }))
+                .build();
     }
 
+    public boolean isReady() {
+        return ready && jda != null && jda.getStatus() == JDA.Status.CONNECTED;
+    }
 }

discord/src/main/java/com/alttd/webinterface/bot/DiscordSender.java

@@ -0,0 +1,64 @@
+package com.alttd.webinterface.bot;
+
+import lombok.extern.slf4j.Slf4j;
+import net.dv8tion.jda.api.entities.channel.concrete.TextChannel;
+
+import java.util.List;
+import java.util.Objects;
+import java.util.Optional;
+
+@Slf4j
+public class DiscordSender {
+
+    private static final DiscordSender INSTANCE = new DiscordSender();
+
+    private final DiscordBotInstance botInstance = new DiscordBotInstance();
+
+    private DiscordSender() {}
+
+    public static DiscordSender getInstance() {
+        return INSTANCE;
+    }
+
+    private void ensureStarted() {
+        if (botInstance.getJda() != null) return;
+        String token = Optional.ofNullable(System.getenv("DISCORD_TOKEN"))
+                .orElse(System.getProperty("DISCORD_TOKEN"));
+        if (token == null || token.isBlank()) {
+            log.error("Discord token not found. Set DISCORD_TOKEN as an environment variable or system property.");
+            return;
+        }
+        botInstance.start(token);
+    }
+
+    public void sendMessageToChannels(List<Long> channelIds, String message) {
+        ensureStarted();
+        if (botInstance.getJda() == null) {
+            log.error("JDA not initialized; cannot send Discord message.");
+            return;
+        }
+        try {
+            if (!botInstance.isReady()) {
+                botInstance.getJda().awaitReady();
+            }
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+        } catch (Exception e) {
+            log.warn("Error while waiting for JDA ready state", e);
+        }
+
+        channelIds.stream()
+                .filter(Objects::nonNull)
+                .forEach(id -> {
+                    TextChannel channel = botInstance.getJda().getChannelById(TextChannel.class, id);
+                    if (channel == null) {
+                        log.warn("TextChannel with id {} not found", id);
+                        return;
+                    }
+                    channel.sendMessage(message).queue(
+                            success -> log.debug("Sent message to channel {}", id),
+                            error -> log.error("Failed sending message to channel {}", id, error)
+                    );
+                });
+    }
+}

discord/src/main/java/com/alttd/webinterface/bot/ReadyListener.java

@@ -0,0 +1,26 @@
+package com.alttd.webinterface.bot;
+
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import net.dv8tion.jda.api.events.session.ReadyEvent;
+import net.dv8tion.jda.api.hooks.ListenerAdapter;
+import org.jetbrains.annotations.NotNull;
+
+@Slf4j
+@RequiredArgsConstructor
+public class ReadyListener extends ListenerAdapter {
+
+    private final Runnable onReadyCallback;
+
+    @Override
+    public void onReady(@NotNull ReadyEvent event) {
+        log.info("JDA is ready. Guilds loaded: {}", event.getJDA().getGuilds().size());
+        if (onReadyCallback != null) {
+            try {
+                onReadyCallback.run();
+            } catch (Exception e) {
+                log.error("Error running onReady callback", e);
+            }
+        }
+    }
+}