(function () {
  'use strict';

  const ENDPOINT = '/visitor_log.php';
  const VISITOR_KEY = 'kvhs_visitor_id_v1';
  const SESSION_KEY = 'kvhs_visitor_session_v1';
  const SESSION_TTL_MS = 30 * 60 * 1000;

  let pageStartMs = Date.now();
  let maxScrollPercent = 0;
  let lastScrollReportPercent = 0;
  let visibleSectionsSeen = {};
  let audioHooked = false;

  function now() {
    return Date.now();
  }

  function makeId(prefix) {
    if (window.crypto && typeof window.crypto.randomUUID === 'function') {
      return prefix + '_' + window.crypto.randomUUID();
    }

    return prefix + '_' + now().toString(36) + '_' + Math.random().toString(36).slice(2);
  }

  function safeGet(key) {
    try {
      return localStorage.getItem(key) || '';
    } catch (err) {
      return '';
    }
  }

  function safeSet(key, value) {
    try {
      localStorage.setItem(key, value);
    } catch (err) {}
  }

  function visitorId() {
    let id = safeGet(VISITOR_KEY);

    if (!id) {
      id = makeId('kvhs_visitor');
      safeSet(VISITOR_KEY, id);
    }

    return id;
  }

  function sessionId() {
    let row = null;

    try {
      row = JSON.parse(safeGet(SESSION_KEY) || 'null');
    } catch (err) {
      row = null;
    }

    if (!row || !row.id || !row.updated_at || (now() - Number(row.updated_at)) > SESSION_TTL_MS) {
      row = {
        id: makeId('kvhs_session'),
        created_at: now(),
        updated_at: now()
      };
    } else {
      row.updated_at = now();
    }

    safeSet(SESSION_KEY, JSON.stringify(row));

    return row.id;
  }

  function connectionLabel() {
    const c = navigator.connection || navigator.mozConnection || navigator.webkitConnection;

    if (!c) return '';

    return [
      c.effectiveType || '',
      c.downlink ? String(c.downlink) + 'mbps' : '',
      c.saveData ? 'save-data' : ''
    ].filter(Boolean).join(' / ');
  }

  function pagePath() {
    return location.pathname + location.search;
  }

  function pageAgeSeconds() {
    return Math.max(0, Math.round((Date.now() - pageStartMs) / 1000));
  }

  function scrollPercent() {
    const doc = document.documentElement || document.body;
    const body = document.body;

    const scrollTop = window.scrollY || doc.scrollTop || body.scrollTop || 0;
    const scrollHeight = Math.max(
      doc.scrollHeight || 0,
      body.scrollHeight || 0,
      doc.offsetHeight || 0,
      body.offsetHeight || 0
    );

    const viewportHeight = window.innerHeight || doc.clientHeight || 0;
    const possible = Math.max(1, scrollHeight - viewportHeight);

    return Math.max(0, Math.min(100, Math.round((scrollTop / possible) * 100)));
  }

  function updateMaxScroll() {
    maxScrollPercent = Math.max(maxScrollPercent, scrollPercent());
    return maxScrollPercent;
  }

  function screenText() {
    return window.screen
      ? String(screen.width || '') + 'x' + String(screen.height || '')
      : '';
  }

  function viewportText() {
    return String(window.innerWidth || '') + 'x' + String(window.innerHeight || '');
  }

  function loadTiming() {
    let out = {
      load_ms: null,
      dom_ready_ms: null,
      first_byte_ms: null,
      transfer_ms: null
    };

    try {
      const nav = performance.getEntriesByType && performance.getEntriesByType('navigation')[0];

      if (nav) {
        out.load_ms = nav.loadEventEnd ? Math.round(nav.loadEventEnd) : null;
        out.dom_ready_ms = nav.domContentLoadedEventEnd ? Math.round(nav.domContentLoadedEventEnd) : null;
        out.first_byte_ms = nav.responseStart ? Math.round(nav.responseStart) : null;
        out.transfer_ms = nav.responseEnd && nav.responseStart ? Math.round(nav.responseEnd - nav.responseStart) : null;
      }
    } catch (err) {}

    return out;
  }

  function basePayload(eventName, extra) {
    const timing = loadTiming();

    return Object.assign({
      event: eventName,
      visitor_id: visitorId(),
      session_id: sessionId(),
      page: location.href,
      page_path: pagePath(),
      page_title: document.title || '',
      referrer: document.referrer || '',
      user_agent: navigator.userAgent || '',
      language: navigator.language || '',
      languages: Array.isArray(navigator.languages) ? navigator.languages.join(', ') : '',
      timezone: (Intl.DateTimeFormat && Intl.DateTimeFormat().resolvedOptions().timeZone) || '',
      screen: screenText(),
      viewport: viewportText(),
      pixel_ratio: String(window.devicePixelRatio || ''),
      color_scheme: window.matchMedia && window.matchMedia('(prefers-color-scheme: dark)').matches ? 'dark' : 'light',
      touch: ('ontouchstart' in window) || (navigator.maxTouchPoints > 0),
      connection: connectionLabel(),

      /* MAX MODE fields */
      page_age_seconds: pageAgeSeconds(),
      max_scroll_percent: updateMaxScroll(),
      visible_sections: Object.keys(visibleSectionsSeen).join(', '),

      /* old timing field kept for compatibility */
      load_ms: timing.load_ms,

      /* expanded timing fields */
      dom_ready_ms: timing.dom_ready_ms,
      first_byte_ms: timing.first_byte_ms,
      transfer_ms: timing.transfer_ms
    }, extra || {});
  }

  function send(eventName, extra) {
    const payload = JSON.stringify(basePayload(eventName, extra));

    if (navigator.sendBeacon) {
      const blob = new Blob([payload], { type: 'application/json' });

      if (navigator.sendBeacon(ENDPOINT, blob)) {
        return;
      }
    }

    fetch(ENDPOINT, {
      method: 'POST',
      cache: 'no-store',
      keepalive: true,
      headers: {
        'Content-Type': 'application/json'
      },
      body: payload
    }).catch(function () {});
  }

  function trimmedText(el) {
    if (!el) return '';

    return String(el.innerText || el.textContent || el.getAttribute('aria-label') || el.title || '')
      .replace(/\s+/g, ' ')
      .trim()
      .slice(0, 180);
  }

  function classifyClick(target, href) {
    const hay = [
      href || '',
      target && target.id || '',
      target && target.className || '',
      trimmedText(target)
    ].join(' ').toLowerCase();

    if (
      hay.includes('cast1.sql2.smrn.com') ||
      hay.includes('listen live') ||
      hay.includes('listen now') ||
      hay.includes('stream')
    ) {
      return 'listen_click';
    }

    if (hay.includes('notes')) return 'notes_click';
    if (hay.includes('listening-room') || hay.includes('listening room')) return 'listening_room_click';
    if (hay.includes('calendar')) return 'calendar_click';
    if (hay.includes('music_history')) return 'music_history_click';
    if (hay.includes('heart') || hay.includes('♥') || hay.includes('♡')) return 'heart_click';
    if (hay.includes('about this song') || hay.includes('current transmission')) return 'about_song_click';

    return 'click';
  }

  function isOutboundHref(href) {
    if (!href) return false;

    try {
      const url = new URL(href, location.href);
      return url.hostname && url.hostname !== location.hostname;
    } catch (err) {
      return false;
    }
  }

  function sectionNameFromElement(el) {
    if (!el) return '';

    const id = String(el.id || '').toLowerCase();
    const cls = String(el.className || '').toLowerCase();
    const txt = trimmedText(el).toLowerCase();

    const hay = [id, cls, txt].join(' ');

    if (hay.includes('now playing') || hay.includes('now-playing') || hay.includes('album')) return 'now_playing';
    if (hay.includes('about this song') || hay.includes('current transmission')) return 'about_song';
    if (hay.includes('calendar')) return 'calendar';
    if (hay.includes('listener notes') || hay.includes('notes')) return 'listener_notes';
    if (hay.includes('listening room')) return 'listening_room';
    if (hay.includes('recent transmissions') || hay.includes('earlier transmissions')) return 'transmission_log';
    if (hay.includes('listen live') || hay.includes('kvhs-player')) return 'listen_bar';

    return '';
  }

  function scanVisibleSections() {
    const selectors = [
      '#song-info-box',
      '#home-calendar-mini',
      '#home-notes',
      '#kvhs-player',
      '.now-playing-card',
      '.left-card',
      '.side-card',
      '.log-housing',
      '.listening-room-card',
      '.bottom-bar',
      '.live-player-nav'
    ];

    const seenNow = [];

    selectors.forEach(function (selector) {
      let nodes = [];

      try {
        nodes = Array.prototype.slice.call(document.querySelectorAll(selector));
      } catch (err) {
        nodes = [];
      }

      nodes.forEach(function (el) {
        const rect = el.getBoundingClientRect();

        if (
          rect.width > 0 &&
          rect.height > 0 &&
          rect.bottom > 0 &&
          rect.top < (window.innerHeight || document.documentElement.clientHeight || 0)
        ) {
          const name = sectionNameFromElement(el);

          if (name && !visibleSectionsSeen[name]) {
            visibleSectionsSeen[name] = true;
            seenNow.push(name);
          }
        }
      });
    });

    if (seenNow.length) {
      send('section_view', {
        section_names: seenNow.join(', '),
        section_count: seenNow.length
      });
    }
  }

  function hookAudioPlayer() {
    if (audioHooked) return;

    const audio = document.querySelector('audio, #kvhs-player');

    if (!audio) return;

    audioHooked = true;

    ['play', 'pause', 'ended', 'waiting', 'playing', 'error', 'stalled'].forEach(function (name) {
      audio.addEventListener(name, function () {
        let currentTime = null;
        let duration = null;
        let paused = null;
        let src = '';

        try {
          currentTime = Math.round(audio.currentTime || 0);
          duration = isFinite(audio.duration) ? Math.round(audio.duration || 0) : null;
          paused = !!audio.paused;
          src = audio.currentSrc || audio.src || '';
        } catch (err) {}

        send('audio_' + name, {
          audio_current_time: currentTime,
          audio_duration: duration,
          audio_paused: paused,
          audio_src: src
        });
      });
    });
  }

  function setupScrollReporting() {
    let timer = null;

    window.addEventListener('scroll', function () {
      updateMaxScroll();

      if (timer) return;

      timer = setTimeout(function () {
        timer = null;

        const current = updateMaxScroll();

        if (current >= lastScrollReportPercent + 25 || current >= 95) {
          lastScrollReportPercent = current;

          send('scroll_depth', {
            scroll_percent: current
          });
        }

        scanVisibleSections();
      }, 700);
    }, { passive: true });
  }

  document.addEventListener('click', function (event) {
    const target = event.target && event.target.closest
      ? event.target.closest('a, button, summary, input, select, textarea, [role="button"]')
      : null;

    if (!target) return;

    const href = target.href || target.getAttribute('href') || '';
    const eventName = isOutboundHref(href) ? 'outbound_click' : classifyClick(target, href);

    send(eventName, {
      event_target: String(target.tagName || '').toLowerCase() + (target.id ? '#' + target.id : ''),
      event_text: trimmedText(target),
      event_href: href,
      outbound_host: isOutboundHref(href) ? (new URL(href, location.href)).hostname : ''
    });
  }, true);

  window.addEventListener('error', function (event) {
    send('js_error', {
      error_message: String(event.message || '').slice(0, 300),
      error_source: String(event.filename || '').slice(0, 240),
      error_line: event.lineno || null,
      error_column: event.colno || null
    });
  });

  window.addEventListener('unhandledrejection', function (event) {
    let reason = '';

    try {
      reason = event.reason && event.reason.message
        ? event.reason.message
        : String(event.reason || '');
    } catch (err) {
      reason = 'Unhandled promise rejection';
    }

    send('js_error', {
      error_message: reason.slice(0, 300),
      error_source: 'unhandledrejection',
      error_line: null,
      error_column: null
    });
  });

  window.addEventListener('load', function () {
    hookAudioPlayer();
    setupScrollReporting();
    scanVisibleSections();

    send('page_view');

    setTimeout(function () {
      hookAudioPlayer();
      scanVisibleSections();
      send('page_ready');
    }, 1200);

    setTimeout(function () {
      scanVisibleSections();
    }, 3500);
  });

  document.addEventListener('visibilitychange', function () {
    const eventName = document.visibilityState === 'hidden' ? 'page_hidden' : 'page_visible';

    send(eventName, {
      page_age_seconds: pageAgeSeconds(),
      max_scroll_percent: updateMaxScroll()
    });
  });

  window.addEventListener('beforeunload', function () {
    send('page_exit', {
      page_age_seconds: pageAgeSeconds(),
      max_scroll_percent: updateMaxScroll()
    });
  });

  setInterval(function () {
    if (document.visibilityState !== 'hidden') {
      hookAudioPlayer();
      scanVisibleSections();

      send('heartbeat', {
        page_age_seconds: pageAgeSeconds(),
        max_scroll_percent: updateMaxScroll()
      });
    }
  }, 60000);

  window.KVHSVisitorPing = {
    send: send
  };
})();