/**
 * Staff notification service – reply alerts and unclaimed ticket reminders.
 *
 * notifyStaffOfReply: posts in the claimer's notification channel when a
 * non-staff user replies, respecting a per-staff cooldown.
 *
 * notifyAllStaffUnclaimed: background job that checks unclaimed tickets
 * against configurable hour thresholds and posts one alert per threshold
 * per ticket (highest newly-crossed threshold only).
 */
const { mongoose } = require('../db-connection');
const { CONFIG, parseThresholdString } = require('../config');
const { increment } = require('./patternStore');
const { enqueueSend } = require('./channelQueue');

const Ticket = mongoose.model('Ticket');
const StaffNotification = mongoose.model('StaffNotification');

// In-memory cooldown map: `${userId}:${ticketId}` -> last notified timestamp
const replyCooldowns = new Map();

/**
 * Notify the claiming staff member when a non-staff user replies.
 * Respects the staff member's cooldownHours setting (default 1h).
 * Posts in their notification channel if one exists.
 */
async function notifyStaffOfReply(guild, ticket, message) {
  if (!ticket.claimerId) return;

  const staffRecord = await StaffNotification.findOne({ userId: ticket.claimerId }).lean();
  if (!staffRecord?.channelId) return;

  const cooldownMs = (staffRecord.cooldownHours || 1) * 60 * 60 * 1000;
  const cooldownKey = `${ticket.claimerId}:${ticket.gmailThreadId}`;
  const lastNotified = replyCooldowns.get(cooldownKey) || 0;
  if (Date.now() - lastNotified < cooldownMs) return;

  const notifChannel = await guild.channels.fetch(staffRecord.channelId).catch(() => null);
  if (!notifChannel) return;

  const jumpLink = `https://discord.com/channels/${guild.id}/${message.channel.id}/${message.id}`;
  const snippet = message.content?.slice(0, 300) || '(no text)';
  await enqueueSend(
    notifChannel,
    `New reply in **${message.channel.name}** from ${message.author.tag}:\n> ${snippet}\n[Jump to message](${jumpLink})`
  );

  replyCooldowns.set(cooldownKey, Date.now());
}

/**
 * Background job: check all open unclaimed tickets against hour thresholds.
 * For each ticket, find the highest threshold that has been crossed but not
 * yet recorded. Post one notification per ticket per run (the highest new
 * threshold) into every staff notification channel.
 */
async function notifyAllStaffUnclaimed(client) {
  const rawThresholds = (CONFIG.NOTIFICATION_THRESHOLDS && CONFIG.NOTIFICATION_THRESHOLDS.unclaimed_reminder) || [];
  const thresholds = rawThresholds
    .map(parseThresholdString)
    .filter(n => Number.isFinite(n) && n >= 0)
    .map(ms => ms / (60 * 60 * 1000));
  if (thresholds.length === 0) return;

  const sorted = [...thresholds].sort((a, b) => a - b);
  const now = Date.now();

  const unclaimedTickets = await Ticket.find({
    status: 'open',
    claimedBy: null,
    createdAt: { $ne: null }
  }).lean();

  if (unclaimedTickets.length === 0) return;

  const staffRecords = await StaffNotification.find({ channelId: { $ne: null } }).lean();
  if (staffRecords.length === 0) return;

  const guild = CONFIG.DISCORD_GUILD_ID
    ? client.guilds.cache.get(CONFIG.DISCORD_GUILD_ID)
    : client.guilds.cache.first();
  if (!guild) return;

  for (const ticket of unclaimedTickets) {
    const ageMs = now - new Date(ticket.createdAt).getTime();
    const ageHours = ageMs / (60 * 60 * 1000);
    const alreadySent = ticket.unclaimedRemindersSent || [];

    // Find thresholds crossed but not yet sent
    const crossedNew = sorted.filter(t => ageHours >= t && !alreadySent.includes(t));
    if (crossedNew.length === 0) continue;

    // Only send the highest newly-crossed threshold
    const highest = crossedNew[crossedNew.length - 1];

    const channelName = ticket.discordThreadId
      ? `<#${ticket.discordThreadId}>`
      : `ticket #${ticket.ticketNumber}`;
    const hoursAgo = Math.floor(ageHours);
    const alertMsg = `Unclaimed ticket alert: ${channelName} has been unclaimed for ${hoursAgo}+ hour(s) (${highest}h threshold).`;

    for (const rec of staffRecords) {
      const chan = await guild.channels.fetch(rec.channelId).catch(() => null);
      if (chan) {
        await enqueueSend(chan, alertMsg).catch(e => console.error('Unclaimed notify send:', e));
        increment('staff_stale_pings', rec.userId, 'today');
        increment('staff_stale_pings', rec.userId, 'week');
      }
    }

    await Ticket.updateOne(
      { gmailThreadId: ticket.gmailThreadId },
      { $addToSet: { unclaimedRemindersSent: highest } }
    );
  }
}

module.exports = { notifyStaffOfReply, notifyAllStaffUnclaimed };