import { nextDailyRunAt } from '../schedule-time.mjs';
import {
  formatPushSubscriptionTimeLabel,
  getPushSubscriptionByKey,
  LEGACY_MORNING_SOURCE,
  pushSubscriptionMetadataSource,
  resolvePushSubscriptionFromMetadataSource,
} from './push-subscription-catalog.mjs';

function metadataSourcesForItem(item) {
  const sources = [pushSubscriptionMetadataSource(item.key)];
  if (item.key === 'morning') {
    sources.push(LEGACY_MORNING_SOURCE);
  }
  return sources;
}

function mapScheduleItemToSubscription(item) {
  const catalogItem = resolvePushSubscriptionFromMetadataSource(item.metadata?.source);
  if (!catalogItem) return null;
  return {
    item,
    catalogItem,
    hour: Number(item.metadata?.dailyHour ?? catalogItem.defaultHour),
    minute: Number(item.metadata?.dailyMinute ?? catalogItem.defaultMinute),
    options: item.metadata?.options ?? null,
  };
}

export async function listActivePushSubscriptions({ userId, scheduleService }) {
  if (!userId || !scheduleService) return [];
  const items = await scheduleService.listItems({ userId, status: 'active', limit: 200 });
  const seen = new Set();
  const subscriptions = [];
  for (const item of items) {
    const mapped = mapScheduleItemToSubscription(item);
    if (!mapped || seen.has(mapped.catalogItem.key)) continue;
    seen.add(mapped.catalogItem.key);
    subscriptions.push(mapped);
  }
  return subscriptions.sort((a, b) => a.catalogItem.id - b.catalogItem.id);
}

export async function findActivePushSubscription({
  userId,
  scheduleService,
  catalogItem,
}) {
  if (!userId || !scheduleService || !catalogItem) return null;
  if (typeof scheduleService.findActiveItemByMetadataSource !== 'function') return null;
  for (const source of metadataSourcesForItem(catalogItem)) {
    const item = await scheduleService.findActiveItemByMetadataSource({ userId, source });
    if (item) return mapScheduleItemToSubscription(item);
  }
  return null;
}

export async function commitPushSubscription({
  userId,
  scheduleService,
  catalogItem,
  hour,
  minute,
  timezone = 'Asia/Shanghai',
  sourceChannel = 'wechat',
  sourceMessageId = null,
  sourceText = '',
  options = null,
}) {
  if (!userId) throw new Error('缺少用户');
  if (!scheduleService) throw new Error('scheduleService 不可用');
  if (!catalogItem?.key) throw new Error('订阅项无效');

  const source = pushSubscriptionMetadataSource(catalogItem.key);
  const existing = await findActivePushSubscription({ userId, scheduleService, catalogItem });

  if (existing?.item?.id) {
    const updated = await scheduleService.updateDailyScheduleItem({
      userId,
      itemId: existing.item.id,
      hour,
      minute,
      timezone,
    });
    if (options && typeof scheduleService.updateScheduleItemMetadata === 'function') {
      await scheduleService.updateScheduleItemMetadata({
        userId,
        itemId: existing.item.id,
        metadata: {
          ...(existing.item.metadata ?? {}),
          source,
          recurrence: 'daily',
          dailyHour: hour,
          dailyMinute: minute,
          subscriptionKey: catalogItem.key,
          options: {
            ...(existing.item.metadata?.options ?? {}),
            ...options,
          },
        },
      });
    }
    return updated;
  }

  const remindAt = nextDailyRunAt({ hour, minute, timezone });
  const item = await scheduleService.createItem({
    userId,
    kind: 'event',
    title: catalogItem.label,
    startAt: remindAt,
    timezone,
    sourceChannel,
    sourceMessageId,
    sourceText,
    metadata: {
      source,
      recurrence: 'daily',
      dailyHour: hour,
      dailyMinute: minute,
      subscriptionKey: catalogItem.key,
      ...(options ? { options } : {}),
    },
  });
  const reminder = await scheduleService.createReminder({
    userId,
    itemId: item.id,
    remindAt,
    channel: 'wechat',
  });
  return { item, reminder };
}

export async function updatePushSubscriptionOptions({
  userId,
  scheduleService,
  catalogItem,
  options,
  timezone = 'Asia/Shanghai',
}) {
  const active = await findActivePushSubscription({ userId, scheduleService, catalogItem });
  if (!active?.item?.id) throw new Error('订阅不存在');
  if (typeof scheduleService.updateScheduleItemMetadata !== 'function') {
    throw new Error('当前不支持更新订阅选项');
  }
  return scheduleService.updateScheduleItemMetadata({
    userId,
    itemId: active.item.id,
    metadata: {
      ...(active.item.metadata ?? {}),
      options: {
        ...(active.item.metadata?.options ?? {}),
        ...(options ?? {}),
      },
    },
  });
}

export async function updatePushSubscriptionTime({
  userId,
  scheduleService,
  catalogItem,
  hour,
  minute,
  timezone = 'Asia/Shanghai',
}) {
  const active = await findActivePushSubscription({ userId, scheduleService, catalogItem });
  if (!active?.item?.id) throw new Error('订阅不存在');
  return scheduleService.updateDailyScheduleItem({
    userId,
    itemId: active.item.id,
    hour,
    minute,
    timezone,
  });
}

export async function cancelPushSubscription({
  userId,
  scheduleService,
  catalogItem,
  reason = '用户取消订阅',
}) {
  const active = await findActivePushSubscription({ userId, scheduleService, catalogItem });
  if (!active?.item?.id) throw new Error('订阅不存在');
  return scheduleService.cancelScheduleItem({
    userId,
    itemId: active.item.id,
    reason,
  });
}

export async function cancelAllPushSubscriptions({
  userId,
  scheduleService,
  reason = '用户取消全部订阅',
}) {
  const subscriptions = await listActivePushSubscriptions({ userId, scheduleService });
  const results = [];
  for (const subscription of subscriptions) {
    results.push(await cancelPushSubscription({
      userId,
      scheduleService,
      catalogItem: subscription.catalogItem,
      reason,
    }));
  }
  return results;
}

export function formatPushSubscriptionCommittedReply({ catalogItem, hour, minute, options = null }) {
  const timeLabel = formatPushSubscriptionTimeLabel(hour, minute);
  const lines = [
    `已开启 ${catalogItem.emoji} ${catalogItem.label}，以后每天 ${timeLabel} 我会推送到本服务号。`,
  ];
  if (catalogItem.key === 'weather') {
    const city = options?.city ?? '北京';
    lines.push(`当前城市：${city}。可说「${catalogItem.id}改城市上海」更换。`);
  }
  lines.push(`回复「取消${catalogItem.id}」可关闭。`);
  return lines.join('');
}

export function formatPushSubscriptionCityUpdatedReply({ catalogItem, options }) {
  const city = options?.city ?? '';
  return `好的，${catalogItem.emoji} ${catalogItem.label} 已改为 ${city}。`;
}

export function formatPushSubscriptionUpdatedReply({ catalogItem, hour, minute }) {
  const timeLabel = formatPushSubscriptionTimeLabel(hour, minute);
  return `好的，${catalogItem.emoji} ${catalogItem.label} 已改到 ${timeLabel}。`;
}

export function formatPushSubscriptionCancelledReply({ catalogItem }) {
  return `已取消 ${catalogItem.emoji} ${catalogItem.label}。`;
}

export function formatPushSubscriptionCancelledAllReply({ count }) {
  if (!count) return '你当前没有开通中的每日推送。';
  return `已取消 ${count} 项每日推送。`;
}

export function formatPushSubscriptionNotReadyReply({ catalogItem }) {
  return `${catalogItem.emoji} ${catalogItem.label} 即将上线，敬请期待。上线后回复 ${catalogItem.id} 即可开通。`;
}

export function formatPushSubscriptionBindFirstReply({ bindUrl }) {
  const normalizedBindUrl = String(bindUrl ?? '').trim();
  const lines = ['若要开通每日推送，请先完成绑定，再回复对应数字确认。'];
  if (normalizedBindUrl) lines.push(normalizedBindUrl);
  return lines.join('\n');
}

export function formatPushSubscriptionListReply({ subscriptions }) {
  if (!subscriptions.length) {
    return '你还没有开通任何每日推送。回复「订阅帮助」查看可订阅项目。';
  }
  const lines = ['你已开通：'];
  for (const entry of subscriptions) {
    const timeLabel = formatPushSubscriptionTimeLabel(entry.hour, entry.minute);
    const citySuffix = entry.catalogItem.key === 'weather' && entry.options?.city
      ? `（${entry.options.city}）`
      : '';
    lines.push(`${entry.catalogItem.id} ${entry.catalogItem.emoji} ${entry.catalogItem.label} ${timeLabel}${citySuffix}`);
  }
  lines.push('', '可说「2改到7点」改时间，或「取消2」关闭。');
  return lines.join('\n');
}

export function formatPushSubscriptionModifyHelpReply({ catalogItem, hour, minute }) {
  const timeLabel = formatPushSubscriptionTimeLabel(hour, minute);
  return `当前 ${catalogItem.emoji} ${catalogItem.label} 为 ${timeLabel}。可说「${catalogItem.id}改到7点」或「取消${catalogItem.id}」。`;
}

export function formatPushSubscriptionAlreadyActiveReply({ catalogItem, hour, minute }) {
  const timeLabel = formatPushSubscriptionTimeLabel(hour, minute);
  return `${catalogItem.emoji} ${catalogItem.label} 已在 ${timeLabel} 推送。可说「${catalogItem.id}改到8点」调整时间。`;
}

export function isWechatPushSubscriptionSource(source) {
  const raw = String(source ?? '').trim();
  if (!raw) return false;
  if (raw === LEGACY_MORNING_SOURCE) return true;
  return raw.startsWith('wechat_push:');
}

export function resolveWechatPushSubscriptionKey(source) {
  const item = resolvePushSubscriptionFromMetadataSource(source);
  return item?.key ?? null;
}

export function getMorningCatalogItem() {
  return getPushSubscriptionByKey('morning');
}