// Copyright: © 2026 TWWIM UG. All rights reserved. (www.twwim.com)
/**
 * Wait-time + SLA helpers for the Communication Center.
 *
 * "Reply time" = gap between the visitor's most recent message and the next
 * outbound message (assistant or operator). When the gap exceeds the
 * threshold the row gets a visual urgency cue.
 *
 * Thresholds: 60 s warn (amber), 180 s breach (red + pulse).
 */

import type { ConversationListItem, ConversationDetail } from './types';

export type WaitUrgency = 'none' | 'warn' | 'breach';

const WARN_THRESHOLD_MS = 60_000;
const BREACH_THRESHOLD_MS = 180_000;

export function visitorWaitMsItem(conv: ConversationListItem, now: Date = new Date()): number {
  if (conv.status === 'closed') return 0;
  if (!conv.lastMessage) return 0;
  if (conv.lastMessage.role !== 'user') return 0;
  return now.getTime() - new Date(conv.lastMessage.createdAt).getTime();
}

export function visitorWaitMsDetail(conv: ConversationDetail, now: Date = new Date()): number {
  if (conv.status === 'closed') return 0;
  const last = conv.messages[conv.messages.length - 1];
  if (!last || last.role !== 'user') return 0;
  return now.getTime() - new Date(last.createdAt).getTime();
}

export function urgencyFor(waitMs: number): WaitUrgency {
  if (waitMs >= BREACH_THRESHOLD_MS) return 'breach';
  if (waitMs >= WARN_THRESHOLD_MS) return 'warn';
  return 'none';
}

export function urgencyOfConversationItem(conv: ConversationListItem, now: Date = new Date()): WaitUrgency {
  return urgencyFor(visitorWaitMsItem(conv, now));
}

export function formatWait(waitMs: number): string {
  const seconds = Math.floor(waitMs / 1000);
  if (seconds < 60) return `${seconds}s`;
  const minutes = Math.floor(seconds / 60);
  if (minutes < 60) return `${minutes}m`;
  const hours = Math.floor(minutes / 60);
  return `${hours}h`;
}