var express = require("express");
var router = express.Router();
const moment = require("moment-timezone");

// Helper: Group timezones by region for the timezone selection screen
function getTimezoneGroups() {
  const regions = {
    "USA/CANADA": [
      "America/Los_Angeles",
      "America/Denver",
      "America/New_York",
      "America/Halifax",
    ],
    EUROPE: [
      "Europe/Berlin",
      "Europe/Helsinki",
      "Europe/Dublin",
      "Europe/Samara",
    ],
    ASIA: ["Asia/Hong_Kong", "Asia/Jakarta", "Asia/Kabul", "Asia/Kathmandu"],
    "SOUTH AMERICA": [
      "America/Bogota",
      "America/Campo_Grande",
      "America/Caracas",
      "America/Lima",
    ],
  };
  const groups = {};
  for (const region in regions) {
    groups[region] = regions[region].map((tz) => ({
      name: tz,
      label: tz.replace(/_/g, " ").replace("America/", ""),
      time_am: moment().tz(tz).format("h:mma"),
      time_24: moment().tz(tz).format("HH:mm"),
    }));
  }
  return groups;
}

// Helper: All timezones for dropdown
function getAllTimezones() {
  return moment.tz.names().map((tz) => ({
    value: tz,
    label: tz,
  }));
}

// Helper: Generate week days and slots
function getWeekDaysAndSlots(selectedTz, weekOffset = 0) {
  const weekDays = [];
  const today = moment()
    .tz(selectedTz)
    .add(weekOffset * 7, "days");
  for (let i = 0; i < 7; i++) {
    const day = today.clone().add(i, "days");
    weekDays.push({
      label: day.format("dddd"),
      date: day.format("MMMM D"),
      dateISO: day.format("YYYY-MM-DD"),
      slots: [
        "9:00am",
        "9:15am",
        "9:30am",
        "9:45am",
        "10:00am",
        "10:15am",
        "10:30am",
        "10:45am",
        "11:00am",
        "11:15am",
        "11:30am",
        "11:45am",
        "12:00pm",
        "12:15pm",
        "12:30pm",
        "12:45pm",
        "1:00pm",
        "1:15pm",
      ],
    });
  }
  return { weekDays, maxSlots: 17 };
}

// Timezone selection screen
router.get("/timezone", function (req, res) {
  res.render("timezone", {
    timezones: getAllTimezones(),
    timezoneGroups: getTimezoneGroups(),
  });
});

// Calendar slot selection screen
router.get("/calendar", function (req, res) {
  const selectedTimezone = req.query.tz || "America/New_York";
  const weekOffset = parseInt(req.query.week) || 0;
  const { weekDays, maxSlots } = getWeekDaysAndSlots(
    selectedTimezone,
    weekOffset
  );
  res.render("calendar", {
    selectedTimezone,
    weekDays,
    maxSlots,
    showPrevWeek: weekOffset > 0,
    prevWeek: weekOffset - 1,
    nextWeek: weekOffset + 1,
  });
});

// Booking form screen
router.get("/book", function (req, res) {
  const selectedTimezone = req.query.tz || "America/New_York";
  const selectedDate = req.query.date || "";
  const selectedTime = req.query.time || "";
  res.render("booking-form", {
    selectedTimezone,
    selectedDate,
    selectedTime,
  });
});

// Booking POST (simulate success)
router.post("/book", function (req, res) {
  // Here you would save booking info to DB
  res.redirect("/success");
});

// Success screen
router.get("/success", function (req, res) {
  res.render("success");
});

// Home page redirect to timezone selection
router.get("/", function (req, res) {
  res.redirect("/timezone");
});

module.exports = router;