const DEFAULT_APP_URL = "http://127.0.0.1:3000";
const DEFAULT_WARNING_INTERVAL_MINUTES = 5;
const DEFAULT_MORNING_BRIEF_TIME = "07:00";
const LOOP_INTERVAL_MS = 30_000;

const appUrl = normalizeAppUrl(process.env.WTR_APP_URL ?? process.env.NEXT_PUBLIC_APP_URL ?? DEFAULT_APP_URL);
const cronSecret = process.env.NOTIFICATIONS_CRON_SECRET ?? "";
const warningIntervalMinutes = readPositiveNumber(process.env.NOTIFICATIONS_WARNING_INTERVAL_MINUTES, DEFAULT_WARNING_INTERVAL_MINUTES);
const morningBriefTime = normalizeTime(process.env.NOTIFICATIONS_MORNING_BRIEF_TIME ?? DEFAULT_MORNING_BRIEF_TIME);

let lastWarningCheckAt = 0;
let lastMorningBriefDate = "";
let isRunningTick = false;

function normalizeAppUrl(value) {
  return value.replace(/\/+$/, "");
}

function readPositiveNumber(value, fallback) {
  const number = Number(value);
  return Number.isFinite(number) && number > 0 ? number : fallback;
}

function normalizeTime(value) {
  return /^\d{2}:\d{2}$/.test(value) ? value : DEFAULT_MORNING_BRIEF_TIME;
}

function getWarsawDateParts(date = new Date()) {
  const parts = new Intl.DateTimeFormat("en-CA", {
    timeZone: "Europe/Warsaw",
    year: "numeric",
    month: "2-digit",
    day: "2-digit",
    hour: "2-digit",
    minute: "2-digit",
    hourCycle: "h23",
  }).formatToParts(date);
  const part = (type) => parts.find((entry) => entry.type === type)?.value ?? "";
  return {
    dateKey: `${part("year")}-${part("month")}-${part("day")}`,
    time: `${part("hour")}:${part("minute")}`,
  };
}

function isAtOrAfterTime(currentTime, targetTime) {
  return currentTime >= targetTime;
}

async function callNotificationEndpoint(path) {
  const response = await fetch(`${appUrl}${path}`, {
    headers: cronSecret ? { authorization: `Bearer ${cronSecret}` } : {},
  });
  const body = await response.text();
  if (!response.ok) throw new Error(`${path} returned ${response.status}: ${body}`);
  return body;
}

async function tick() {
  if (isRunningTick) return;
  isRunningTick = true;
  try {
    const now = Date.now();
    const warningIntervalMs = warningIntervalMinutes * 60_000;
    if (now - lastWarningCheckAt >= warningIntervalMs) {
      lastWarningCheckAt = now;
      await callNotificationEndpoint("/api/notifications/check");
    }

    const warsawTime = getWarsawDateParts();
    if (isAtOrAfterTime(warsawTime.time, morningBriefTime) && lastMorningBriefDate !== warsawTime.dateKey) {
      await callNotificationEndpoint("/api/notifications/daily-brief");
      lastMorningBriefDate = warsawTime.dateKey;
    }
  } catch (error) {
    console.error(error);
  } finally {
    isRunningTick = false;
  }
}

console.log(`wtr. notification worker: ${appUrl}`);
console.log(`Warnings every ${warningIntervalMinutes} min, morning brief at ${morningBriefTime} Europe/Warsaw.`);
void tick();
setInterval(tick, LOOP_INTERVAL_MS);