/* SAB Events Calendar — week view with Add to Google Calendar + .ics download.
 * Events data lives in a separate JSON file (data-json attribute on the container)
 * so it can be refreshed weekly without touching this script. */
(function () {
  'use strict';

  var CTZ = 'America/Chicago';

  function $(sel, el) { return (el || document).querySelector(sel); }
  function $all(sel, el) { return Array.prototype.slice.call((el || document).querySelectorAll(sel)); }

  function pad(n) { return (n < 10 ? '0' : '') + n; }

  function fmtYMD(d) {
    return d.getFullYear() + '-' + pad(d.getMonth() + 1) + '-' + pad(d.getDate());
  }

  function parseYMD(s) {
    var p = s.split('-');
    return new Date(parseInt(p[0], 10), parseInt(p[1], 10) - 1, parseInt(p[2], 10));
  }

  function startOfWeek(d) {
    var c = new Date(d.getFullYear(), d.getMonth(), d.getDate());
    c.setDate(c.getDate() - c.getDay()); // Sunday
    return c;
  }

  function addDays(d, n) {
    var c = new Date(d.getFullYear(), d.getMonth(), d.getDate());
    c.setDate(c.getDate() + n);
    return c;
  }

  function fmtDay(d) {
    return d.toLocaleDateString('en-US', { weekday: 'long', month: 'long', day: 'numeric' });
  }

  function fmtTime(hhmm) {
    var p = hhmm.split(':'), h = parseInt(p[0], 10), m = p[1];
    var ap = h >= 12 ? 'PM' : 'AM';
    h = h % 12; if (h === 0) h = 12;
    return h + ':' + m + ' ' + ap;
  }

  function gcalDate(ymd, hhmm) {
    return ymd.replace(/-/g, '') + 'T' + hhmm.replace(':', '') + '00';
  }

  function escHtml(s) {
    return String(s).replace(/&/g, '&amp;').replace(/</g, '&lt;')
      .replace(/>/g, '&gt;').replace(/"/g, '&quot;');
  }

  function escIcs(s) {
    return String(s).replace(/\\/g, '\\\\').replace(/;/g, '\\;')
      .replace(/,/g, '\\,').replace(/\n/g, '\\n');
  }

  // Events active on a given day (supports multi-day ranges via endDate).
  function eventsOn(events, ymd) {
    return events.filter(function (e) {
      var end = e.endDate || e.date;
      return e.date <= ymd && ymd <= end;
    });
  }

  function googleCalUrl(e, ymd) {
    var params = [
      'action=TEMPLATE',
      'text=' + encodeURIComponent(e.title),
      'dates=' + gcalDate(ymd, e.start) + '/' + gcalDate(ymd, e.end),
      'details=' + encodeURIComponent(e.desc + (e.source ? '\n\nMore info: ' + e.source : '')),
      'location=' + encodeURIComponent(e.venue + ', ' + e.address),
      'ctz=' + encodeURIComponent(CTZ)
    ];
    return 'https://calendar.google.com/calendar/render?' + params.join('&');
  }

  function icsFor(e, ymd) {
    var uid = e.id + '-' + ymd + '@sanantoniobenefits.com';
    var stamp = new Date().toISOString().replace(/[-:]/g, '').split('.')[0] + 'Z';
    var lines = [
      'BEGIN:VCALENDAR', 'VERSION:2.0',
      'PRODID:-//SanAntonioBenefits//Free Events Calendar//EN',
      'BEGIN:VEVENT',
      'UID:' + uid,
      'DTSTAMP:' + stamp,
      'DTSTART;TZID=' + CTZ + ':' + gcalDate(ymd, e.start),
      'DTEND;TZID=' + CTZ + ':' + gcalDate(ymd, e.end),
      'SUMMARY:' + escIcs(e.title),
      'DESCRIPTION:' + escIcs(e.desc + (e.source ? '\\n\\nMore info: ' + e.source : '')),
      'LOCATION:' + escIcs(e.venue + ', ' + e.address),
      'BEGIN:VALARM', 'TRIGGER:-PT1H', 'ACTION:DISPLAY',
      'DESCRIPTION:' + escIcs('Reminder: ' + e.title),
      'END:VALARM', 'END:VEVENT', 'END:VCALENDAR'
    ];
    return lines.join('\r\n');
  }

  function downloadIcs(e, ymd) {
    var blob = new Blob([icsFor(e, ymd)], { type: 'text/calendar;charset=utf-8' });
    var a = document.createElement('a');
    a.href = URL.createObjectURL(blob);
    a.download = e.id + '-' + ymd + '.ics';
    document.body.appendChild(a);
    a.click();
    setTimeout(function () {
      URL.revokeObjectURL(a.href);
      a.remove();
    }, 1000);
  }

  function eventCard(e, ymd) {
    var card = document.createElement('article');
    card.className = 'sab-ev-card';
    var range = (e.endDate && e.endDate !== e.date)
      ? '<span class="sab-ev-range">' + escHtml(fmtDay(parseYMD(e.date))) + ' – ' + escHtml(fmtDay(parseYMD(e.endDate))) + '</span>'
      : '';
    card.innerHTML =
      '<div class="sab-ev-top"><span class="sab-ev-time">' + escHtml(fmtTime(e.start)) + ' – ' + escHtml(fmtTime(e.end)) + '</span>' +
      '<span class="sab-ev-free">' + escHtml(e.cost || 'Free') + '</span></div>' +
      '<h4 class="sab-ev-title">' + escHtml(e.title) + '</h4>' + range +
      '<div class="sab-ev-venue">' + escHtml(e.venue) + '</div>' +
      '<p class="sab-ev-desc">' + escHtml(e.desc) + '</p>' +
      '<div class="sab-ev-actions"></div>';
    var actions = $('.sab-ev-actions', card);

    if (e.source) {
      var info = document.createElement('a');
      info.href = e.source; info.target = '_blank'; info.rel = 'noopener';
      info.className = 'sab-ev-btn sab-ev-info';
      info.textContent = 'More info';
      actions.appendChild(info);
    }

    var g = document.createElement('a');
    g.href = googleCalUrl(e, ymd); g.target = '_blank'; g.rel = 'noopener';
    g.className = 'sab-ev-btn sab-ev-gcal';
    g.textContent = 'Add to Google Calendar';
    actions.appendChild(g);

    var ics = document.createElement('button');
    ics.type = 'button';
    ics.className = 'sab-ev-btn sab-ev-ics';
    ics.textContent = 'Add to Apple / Outlook (.ics)';
    ics.setAttribute('aria-label', 'Download calendar file with reminder for ' + e.title);
    ics.addEventListener('click', function () { downloadIcs(e, ymd); });
    actions.appendChild(ics);

    return card;
  }

  function render(container, events, weekStart, bounds) {
    container.innerHTML = '';
    var todayYmd = fmtYMD(new Date());

    var head = document.createElement('div');
    head.className = 'sab-ev-head';
    var monthLabel = weekStart.toLocaleDateString('en-US', { month: 'long', year: 'numeric' });
    head.innerHTML =
      '<button type="button" class="sab-ev-nav" data-nav="-1" aria-label="Previous week">‹ Prev</button>' +
      '<div class="sab-ev-weeklabel"><strong>Week of ' + escHtml(weekStart.toLocaleDateString('en-US', { month: 'long', day: 'numeric' })) + '</strong><span>' + escHtml(monthLabel) + '</span></div>' +
      '<button type="button" class="sab-ev-today">Today</button>' +
      '<button type="button" class="sab-ev-nav" data-nav="1" aria-label="Next week">Next ›</button>';
    container.appendChild(head);

    var prev = $('[data-nav="-1"]', head), next = $('[data-nav="1"]', head);
    if (weekStart <= bounds.min) prev.disabled = true;
    if (addDays(weekStart, 7) > bounds.max) next.disabled = true;

    $all('.sab-ev-nav', head).forEach(function (btn) {
      btn.addEventListener('click', function () {
        render(container, events, addDays(weekStart, 7 * parseInt(btn.getAttribute('data-nav'), 10)), bounds);
      });
    });
    $('.sab-ev-today', head).addEventListener('click', function () {
      var now = startOfWeek(new Date());
      if (now < bounds.min) now = bounds.min;
      if (now > bounds.max) now = bounds.max;
      render(container, events, now, bounds);
    });

    var list = document.createElement('div');
    list.className = 'sab-ev-list';
    for (var i = 0; i < 7; i++) {
      var d = addDays(weekStart, i), ymd = fmtYMD(d);
      var day = document.createElement('section');
      day.className = 'sab-ev-day' + (ymd === todayYmd ? ' sab-ev-today-hl' : '') + (ymd < todayYmd ? ' sab-ev-past' : '');
      var dayEvents = eventsOn(events, ymd);
      day.innerHTML = '<h3 class="sab-ev-date">' + escHtml(fmtDay(d)) +
        (ymd === todayYmd ? ' <span class="sab-ev-todaybadge">Today</span>' : '') + '</h3>';
      if (dayEvents.length === 0) {
        var none = document.createElement('p');
        none.className = 'sab-ev-none';
        none.textContent = 'No free events listed for this day yet — check back, we update weekly.';
        day.appendChild(none);
      } else {
        dayEvents.forEach(function (e) { day.appendChild(eventCard(e, ymd)); });
      }
      list.appendChild(day);
    }
    container.appendChild(list);

    var foot = document.createElement('p');
    foot.className = 'sab-ev-foot';
    foot.textContent = 'All events listed here are free. Times are Central. We update this calendar every week — the .ics download includes a 1-hour reminder.';
    container.appendChild(foot);
  }

  function init() {
    $all('.sab-events-cal').forEach(function (container) {
      var url = container.getAttribute('data-json');
      if (!url) return;
      container.innerHTML = '<p class="sab-ev-loading">Loading this week\u2019s free events…</p>';
      fetch(url).then(function (r) {
        if (!r.ok) throw new Error('fetch failed');
        return r.json();
      }).then(function (data) {
        var events = (data.events || []).slice().sort(function (a, b) {
          return a.date < b.date ? -1 : (a.date > b.date ? 1 : (a.start < b.start ? -1 : 1));
        });
        if (!events.length) {
          container.innerHTML = '<p class="sab-ev-none">No events listed right now — check back soon.</p>';
          return;
        }
        var min = startOfWeek(parseYMD(events[0].date));
        var lastEnd = events.reduce(function (m, e) {
          var ed = e.endDate || e.date;
          return ed > m ? ed : m;
        }, events[0].date);
        var max = startOfWeek(parseYMD(lastEnd));
        var now = startOfWeek(new Date());
        if (now < min) now = min;
        if (now > max) now = max;
        render(container, events, now, { min: min, max: max });
      }).catch(function () {
        container.innerHTML = '<p class="sab-ev-none">Could not load the events calendar right now. Please refresh the page.</p>';
      });
    });
  }

  if (document.readyState === 'loading') {
    document.addEventListener('DOMContentLoaded', init);
  } else {
    init();
  }
})();