const axios = require('axios');
const adminConfig = require('./adminConfig');
const { readNotificationSettings } = require('./userSettingsStore');

function formatDateLabel(dateInput) {
  try {
    const date = new Date(dateInput);
    if (Number.isNaN(date.getTime())) {
      return 'unbekanntes Datum';
    }
    return date.toLocaleString('de-DE', {
      weekday: 'short',
      year: 'numeric',
      month: '2-digit',
      day: '2-digit',
      hour: '2-digit',
      minute: '2-digit'
    });
  } catch (_error) {
    return 'unbekanntes Datum';
  }
}

async function sendNtfyNotification(adminNtfy, userNtfy, payload) {
  if (!adminNtfy?.enabled || !userNtfy?.enabled || !userNtfy.topic) {
    return;
  }
  const server = (userNtfy.serverUrl || adminNtfy.serverUrl || 'https://ntfy.sh').replace(/\/+$/, '');
  const sanitizedPrefix = (adminNtfy.topicPrefix || '').replace(/^-+|-+$/g, '');
  const sanitizedTopic = (userNtfy.topic || '').replace(/^-+|-+$/g, '');
  const topic = `${sanitizedPrefix}${sanitizedTopic}` || sanitizedPrefix || sanitizedTopic;
  let url = `${server}/${topic}`;
  if (payload.title) {
    const delimiter = url.includes('?') ? '&' : '?';
    url = `${url}${delimiter}title=${encodeURIComponent(payload.title)}`;
  }
  const headers = {
    Priority: payload.priority || 'default',
    'Content-Type': 'text/plain; charset=utf-8'
  };
  if (adminNtfy.username && adminNtfy.password) {
    const credentials = Buffer.from(`${adminNtfy.username}:${adminNtfy.password}`).toString('base64');
    headers.Authorization = `Basic ${credentials}`;
  }
  await axios.post(url, payload.message, { headers, timeout: 15000 });
}

async function sendTelegramNotification(adminTelegram, userTelegram, payload) {
  if (!adminTelegram?.enabled || !adminTelegram.botToken || !userTelegram?.enabled || !userTelegram.chatId) {
    return;
  }
  const endpoint = `https://api.telegram.org/bot${adminTelegram.botToken}/sendMessage`;
  await axios.post(
    endpoint,
    {
      chat_id: userTelegram.chatId,
      text: payload.title ? `*${payload.title}*\n${payload.message}` : payload.message,
      parse_mode: payload.title ? 'Markdown' : undefined,
      disable_web_page_preview: true
    },
    { timeout: 15000 }
  );
}

async function notifyChannels(profileId, template) {
  const adminSettings = adminConfig.readSettings();
  const userSettings = readNotificationSettings(profileId);
  try {
    await Promise.allSettled([
      sendNtfyNotification(adminSettings.notifications?.ntfy, userSettings.notifications?.ntfy, template),
      sendTelegramNotification(adminSettings.notifications?.telegram, userSettings.notifications?.telegram, template)
    ]);
  } catch (error) {
    console.error('[NOTIFICATIONS] Versand fehlgeschlagen:', error.message);
  }
}

async function sendSlotNotification({ profileId, storeName, pickupDate, onlyNotify, booked, storeId }) {
  const dateLabel = formatDateLabel(pickupDate);
  const title = onlyNotify
    ? `Slot verfügbar bei ${storeName}`
    : booked
    ? `Slot gebucht bei ${storeName}`
    : `Slot gefunden bei ${storeName}`;
  const baseMessage = onlyNotify
    ? `Es wurde ein freier Slot am ${dateLabel} entdeckt.`
    : booked
    ? `Der Slot am ${dateLabel} wurde erfolgreich gebucht.`
    : `Es wurde ein Slot am ${dateLabel} gefunden.`;
  const storeLink = storeId ? `https://foodsharing.de/store/${storeId}` : null;
  const fullMessage = storeLink ? `${baseMessage}\n${storeLink}` : baseMessage;

  await notifyChannels(profileId, {
    title,
    message: fullMessage,
    link: storeLink,
    priority: booked ? 'high' : 'default'
  });
}

async function sendStoreWatchNotification({ profileId, storeName, storeId, regionName }) {
  const storeLink = storeId ? `https://foodsharing.de/store/${storeId}` : null;
  const title = `Team sucht Verstärkung: ${storeName}`;
  const regionText = regionName ? ` (${regionName})` : '';
  const messageBase = `Der Betrieb${regionText} sucht wieder aktiv neue Teammitglieder.`;
  const message = storeLink ? `${messageBase}\n${storeLink}` : messageBase;
  await notifyChannels(profileId, {
    title,
    message,
    link: storeLink,
    priority: 'high'
  });
}

async function sendDesiredWindowMissedNotification({ profileId, storeName, desiredWindowLabel }) {
  if (!profileId) {
    return;
  }
  const title = `Keine Slots gefunden: ${storeName}`;
  const messageBase = desiredWindowLabel
    ? `Für den gewünschten Zeitraum ${desiredWindowLabel} konnte kein Slot gefunden werden.`
    : 'Für den gewünschten Zeitraum konnte kein Slot gefunden werden.';
  const message = `${messageBase} Der Eintrag wurde deaktiviert.`;
  await notifyChannels(profileId, {
    title,
    message,
    link: null,
    priority: 'default'
  });
}

async function sendTestNotification(profileId, channel) {
  const title = 'Pickup Benachrichtigung (Test)';
  const message = 'Das ist eine Testnachricht. Bei Fragen wende dich bitte an den Admin.';
  const adminSettings = adminConfig.readSettings();
  const userSettings = readNotificationSettings(profileId);
  const tasks = [];

  if (!channel || channel === 'ntfy') {
    tasks.push(
      sendNtfyNotification(adminSettings.notifications?.ntfy, userSettings.notifications?.ntfy, {
        title,
        message,
        priority: 'default'
      })
    );
  }
  if (!channel || channel === 'telegram') {
    tasks.push(
      sendTelegramNotification(adminSettings.notifications?.telegram, userSettings.notifications?.telegram, {
        title,
        message,
        priority: 'default'
      })
    );
  }

  if (tasks.length === 0) {
    throw new Error('Kein unterstützter Kanal oder Kanal deaktiviert.');
  }

  await Promise.all(tasks);
}

module.exports = {
  sendSlotNotification,
  sendStoreWatchNotification,
  sendTestNotification,
  sendDesiredWindowMissedNotification
};