import { getDb } from '../db/client.js'
import { publish } from '../plugins/valkey.js'
import { sendToSessionParticipant } from '../plugins/websocket.js'

const sql = getDb()

// Active session timers: sessionId → { warningTimeout, expiryTimeout }
const sessionTimers = new Map()

export const startSessionTimer = (sessionId, expiresAt) => {
  const now = Date.now()
  const expiresMs = new Date(expiresAt).getTime()
  const warningMs = expiresMs - 60_000 // 1 minute before expiry

  // Clear any existing timers
  clearSessionTimer(sessionId)

  const timers = {}

  // Warning timer (1 min before expiry)
  if (warningMs > now) {
    timers.warningTimeout = setTimeout(() => {
      onSessionWarning(sessionId)
    }, warningMs - now)
  }

  // Expiry timer
  if (expiresMs > now) {
    timers.expiryTimeout = setTimeout(() => {
      onSessionExpired(sessionId)
    }, expiresMs - now)
  } else {
    // Already expired
    onSessionExpired(sessionId)
    return
  }

  sessionTimers.set(sessionId, timers)
}

export const clearSessionTimer = (sessionId) => {
  const timers = sessionTimers.get(sessionId)
  if (timers) {
    if (timers.warningTimeout) clearTimeout(timers.warningTimeout)
    if (timers.expiryTimeout) clearTimeout(timers.expiryTimeout)
    sessionTimers.delete(sessionId)
  }
}

export const extendSessionTimer = async (sessionId, additionalMinutes) => {
  const [session] = await sql`
    UPDATE chat_sessions
    SET expires_at = expires_at + ${additionalMinutes + ' minutes'}::interval,
        extended_minutes = extended_minutes + ${additionalMinutes}
    WHERE id = ${sessionId}
    RETURNING id, expires_at
  `
  if (session) {
    startSessionTimer(sessionId, session.expires_at)
  }
  return session
}

const onSessionWarning = (sessionId) => {
  const data = { type: 'session_timer', remaining_seconds: 60, session_id: sessionId }
  sendToSessionParticipant(sessionId, 'customer', data)
  sendToSessionParticipant(sessionId, 'mitra', data)
}

const onSessionExpired = async (sessionId) => {
  clearSessionTimer(sessionId)

  // Check session is still active
  const [session] = await sql`
    SELECT id, status FROM chat_sessions WHERE id = ${sessionId} AND status = 'active'
  `
  if (!session) return

  // Notify both parties
  const data = { type: 'session_expired', session_id: sessionId }
  sendToSessionParticipant(sessionId, 'customer', data)
  sendToSessionParticipant(sessionId, 'mitra', data)

  // Also publish via Valkey for any listeners
  await publish(`session:${sessionId}:status`, data)
}

// Restore timers for active sessions on server restart
export const restoreActiveTimers = async () => {
  const activeSessions = await sql`
    SELECT id, expires_at FROM chat_sessions
    WHERE status = 'active' AND expires_at IS NOT NULL AND expires_at > NOW()
  `
  for (const session of activeSessions) {
    startSessionTimer(session.id, session.expires_at)
  }
  if (activeSessions.length > 0) {
    console.log(`Restored ${activeSessions.length} session timer(s)`)
  }
}