/**
/**
 * OmniCard AI (CRMmp) - 商务日程预约与日历服务 (UTS 强类型版本)
 * 严格对齐 backend/src/modules/card/service/calendar.ts 规范
 */

import { MeetingInviteOptions, CalendarInviteBundle } from './types.uts';
import { getBaseUrl } from './request.uts';

/**
 * 格式化 UTC 时间为 RFC 5545 日期时间戳 (YYYYMMDDTHHmmssZ)
 */
export function formatIcsDate(date: Date | string | number): string {
  const d = date instanceof Date ? date : new Date(date);
  if (isNaN(d.getTime())) {
    return '';
  }
  const pad = (n: number): string => (n < 10 ? '0' + n : String(n));
  const year = d.getUTCFullYear();
  const month = pad(d.getUTCMonth() + 1);
  const day = pad(d.getUTCDate());
  const hours = pad(d.getUTCHours());
  const minutes = pad(d.getUTCMinutes());
  const seconds = pad(d.getUTCSeconds());
  return `${year}${month}${day}T${hours}${minutes}${seconds}Z`;
}

/**
 * 格式化为 ISO 8601 字符串 (用于 Outlook)
 */
export function toIsoDate(date: Date | string | number): string {
  const d = date instanceof Date ? date : new Date(date);
  if (isNaN(d.getTime())) {
    return '';
  }
  return d.toISOString();
}

/**
 * 生成 Google Calendar Web 一键预约 URL
 */
export function generateGoogleCalendarUrl(meeting: MeetingInviteOptions): string {
  const summary = meeting.summary || meeting.title || '商务洽谈';
  const dtStart = formatIcsDate(meeting.startTime);
  const dtEnd = formatIcsDate(meeting.endTime);

  let details = meeting.description || '';
  if (meeting.organizerEmail) {
    details += `\nOrganizer: ${meeting.organizerEmail}`;
  }

  const queryParts: string[] = [
    'action=TEMPLATE',
    `text=${encodeURIComponent(summary)}`,
    `dates=${encodeURIComponent(`${dtStart}/${dtEnd}`)}`,
    `details=${encodeURIComponent(details.trim())}`,
    `location=${encodeURIComponent(meeting.location || '')}`,
  ];

  return `https://calendar.google.com/calendar/render?${queryParts.join('&')}`;
}

/**
 * 生成 Outlook Live 一键预约 URL
 */
export function generateOutlookCalendarUrl(meeting: MeetingInviteOptions): string {
  const summary = meeting.summary || meeting.title || '商务洽谈';
  const startDt = toIsoDate(meeting.startTime);
  const endDt = toIsoDate(meeting.endTime);

  const queryParts: string[] = [
    'path=%2Fcalendar%2Faction%2Fcompose',
    'rru=addevent',
    `subject=${encodeURIComponent(summary)}`,
    `startdt=${encodeURIComponent(startDt)}`,
    `enddt=${encodeURIComponent(endDt)}`,
    `body=${encodeURIComponent(meeting.description || '')}`,
    `location=${encodeURIComponent(meeting.location || '')}`,
  ];

  return `https://outlook.live.com/calendar/0/deeplink/compose?${queryParts.join('&')}`;
}

/**
 * 获取后端 RFC 5545 ICS 订阅文件下载 URL
 */
export function getMeetingIcsDownloadUrl(meeting: MeetingInviteOptions): string {
  const baseUrl = getBaseUrl();
  const summary = meeting.summary || meeting.title || '商务洽谈';
  const dtStart = formatIcsDate(meeting.startTime);
  const dtEnd = formatIcsDate(meeting.endTime);

  const queryParts: string[] = [
    `summary=${encodeURIComponent(summary)}`,
    `startTime=${encodeURIComponent(dtStart)}`,
    `endTime=${encodeURIComponent(dtEnd)}`,
    `description=${encodeURIComponent(meeting.description || '')}`,
    `location=${encodeURIComponent(meeting.location || '')}`,
  ];

  if (meeting.organizerName) {
    queryParts.push(`organizerName=${encodeURIComponent(meeting.organizerName)}`);
  }
  if (meeting.organizerEmail) {
    queryParts.push(`organizerEmail=${encodeURIComponent(meeting.organizerEmail)}`);
  }

  return `${baseUrl}/open/card/portal/meeting-ics?${queryParts.join('&')}`;
}

/**
 * 综合生成全平台日历预约包
 */
export function buildCalendarInviteBundle(meeting: MeetingInviteOptions): CalendarInviteBundle {
  return {
    googleUrl: generateGoogleCalendarUrl(meeting),
    outlookUrl: generateOutlookCalendarUrl(meeting),
    icsUrl: getMeetingIcsDownloadUrl(meeting),
  };
}