import { getDb } from '../db/client.js'
import * as valkey from '../plugins/valkey.js'
import { VK_MITRAS_ONLINE } from './mitra-status.service.js'
import { SessionStatus, TopicSensitivity } from '../constants.js'

const sql = getDb()

// Valkey-fast SCARD with Postgres fallback. The CC dashboard polls every few
// seconds; SCARD is sub-ms so this keeps the dashboard responsive at any scale.
const getOnlineMitrasCount = async () => {
  try {
    return await valkey.scard(VK_MITRAS_ONLINE)
  } catch (err) {
    console.warn('[dashboard] valkey unavailable, falling back to DB:', err.message)
    const [{ c }] = await sql`SELECT COUNT(*)::int AS c FROM mitra_online_status WHERE is_online = true`
    return c
  }
}

export const getDashboardStats = async () => {
  const [
    [{ active_chats }],
    online_mitras,
    [{ pending_requests }],
    [{ sensitive_total }],
    [{ sensitive_last_30d_total }],
    [{ sensitive_last_30d_sensitive }],
  ] = await Promise.all([
    sql`SELECT COUNT(*) AS active_chats FROM chat_sessions WHERE status IN (${SessionStatus.ACTIVE}, ${SessionStatus.PENDING_PAYMENT})`,
    getOnlineMitrasCount(),
    sql`SELECT COUNT(*) AS pending_requests FROM chat_sessions WHERE status IN (${SessionStatus.SEARCHING}, ${SessionStatus.PENDING_ACCEPTANCE})`,
    sql`SELECT COUNT(*) AS sensitive_total FROM chat_sessions WHERE topic_sensitivity = ${TopicSensitivity.SENSITIVE}`,
    sql`SELECT COUNT(*) AS sensitive_last_30d_total FROM chat_sessions WHERE created_at >= NOW() - INTERVAL '30 days'`,
    sql`SELECT COUNT(*) AS sensitive_last_30d_sensitive FROM chat_sessions WHERE created_at >= NOW() - INTERVAL '30 days' AND topic_sensitivity = ${TopicSensitivity.SENSITIVE}`,
  ])

  const customersPerMitra = await sql`
    SELECT m.id, m.display_name,
      (SELECT COUNT(*) FROM chat_sessions cs
       WHERE cs.mitra_id = m.id AND cs.status IN (${SessionStatus.ACTIVE}, ${SessionStatus.PENDING_PAYMENT})) AS active_session_count
    FROM mitras m
    INNER JOIN mitra_online_status s ON s.mitra_id = m.id
    WHERE s.is_online = true
    ORDER BY active_session_count DESC
  `

  const last30dTotal = Number(sensitive_last_30d_total)
  const last30dSensitive = Number(sensitive_last_30d_sensitive)

  return {
    active_chats: Number(active_chats),
    online_mitras: Number(online_mitras),
    pending_requests: Number(pending_requests),
    customers_per_mitra: customersPerMitra,
    sensitive: {
      total: Number(sensitive_total),
      last_30d_total: last30dTotal,
      last_30d_sensitive: last30dSensitive,
      last_30d_percent: last30dTotal > 0 ? Math.round((last30dSensitive / last30dTotal) * 1000) / 10 : 0,
    },
  }
}