const WINDOW_MS = 150_000; // 2.5 minutes
const recentPosts = new Map();

function normalizeKey(text) {
  return text.toLowerCase().replace(/\s+/g, " ").trim().slice(0, 200);
}

export function trackCrossChannelMessage(guildId, userId, channelId, messageId, text) {
  const normalized = normalizeKey(text);
  if (!normalized) {
    return { duplicateAcrossChannels: false, priorMessages: [] };
  }

  const key = `${guildId}:${userId}:${normalized}`;
  const now = Date.now();
  const existing = recentPosts.get(key);

  if (existing && now - existing.firstSeen < WINDOW_MS) {
    const priorMessages = [...existing.messages.entries()].map(([chId, msgId]) => ({
      channelId: chId,
      messageId: msgId,
    }));

    existing.channels.add(channelId);
    existing.messages.set(channelId, messageId);

    const duplicateAcrossChannels = existing.channels.size >= 2;
    return { duplicateAcrossChannels, priorMessages: duplicateAcrossChannels ? priorMessages : [] };
  }

  recentPosts.set(key, {
    channels: new Set([channelId]),
    messages: new Map([[channelId, messageId]]),
    firstSeen: now,
  });

  if (recentPosts.size > 5000) {
    for (const [entryKey, entry] of recentPosts) {
      if (now - entry.firstSeen > WINDOW_MS) {
        recentPosts.delete(entryKey);
      }
    }
  }

  return { duplicateAcrossChannels: false, priorMessages: [] };
}