/**
 * AKSRT Yiyan — 一言轮播组件
 *
 * Fetches random quotes from hitokoto.cn API and auto-rotates.
 * Public v1 returns one sentence per request; multi-quote carousels
 * issue parallel fetches. Category `c` must be a letter a–l (or omitted).
 *
 * @package AKSRT
 */

(function () {
  'use strict';

  var API_BASE = 'https://v1.hitokoto.cn/';
  var TYPE_RE = /^[a-l]$/i;
  var MIN_COUNT = 1;
  var MAX_COUNT = 10;
  var DEFAULT_COUNT = 5;
  var DEFAULT_INTERVAL_SEC = 5;

  function normalizeType(raw) {
    if (raw == null || raw === '') {
      return '';
    }
    var t = String(raw).trim().toLowerCase();
    return TYPE_RE.test(t) ? t : '';
  }

  function normalizeCount(raw) {
    var n = parseInt(raw, 10);
    if (isNaN(n) || n < MIN_COUNT) {
      return DEFAULT_COUNT;
    }
    return Math.min(MAX_COUNT, n);
  }

  function normalizeIntervalMs(raw) {
    var sec = parseInt(raw, 10);
    if (isNaN(sec) || sec < 3) {
      sec = DEFAULT_INTERVAL_SEC;
    }
    return Math.min(60, sec) * 1000;
  }

  function buildApiUrl(type) {
    var params = new URLSearchParams();
    params.set('encode', 'json');
    if (type) {
      params.set('c', type);
    }
    return API_BASE + '?' + params.toString();
  }

  function mapQuote(data) {
    if (!data || typeof data !== 'object') {
      return null;
    }
    var text = data.hitokoto || data.text || '';
    if (!text) {
      return null;
    }
    return {
      text: String(text),
      from: data.from ? String(data.from) : '',
    };
  }

  function ensureStructure(el) {
    var textEl = el.querySelector('.aksrt-yiyan__text');
    if (textEl) {
      return {
        textEl: textEl,
        fromEl: el.querySelector('.aksrt-yiyan__from'),
        dotsEl: el.querySelector('.aksrt-yiyan__dots'),
      };
    }

    var content = document.createElement('div');
    content.className = 'aksrt-yiyan__content';

    textEl = document.createElement('p');
    textEl.className = 'aksrt-yiyan__text';
    textEl.textContent = '加载中…';
    content.appendChild(textEl);

    var fromEl = document.createElement('p');
    fromEl.className = 'aksrt-yiyan__from';
    content.appendChild(fromEl);

    el.appendChild(content);

    var dotsEl = document.createElement('div');
    dotsEl.className = 'aksrt-yiyan__dots';
    dotsEl.setAttribute('aria-hidden', 'true');
    el.appendChild(dotsEl);

    return { textEl: textEl, fromEl: fromEl, dotsEl: dotsEl };
  }

  function fetchOneQuote(type) {
    return fetch(buildApiUrl(type), {
      credentials: 'omit',
      mode: 'cors',
    }).then(function (r) {
      return r
        .json()
        .catch(function () {
          return null;
        })
        .then(function (data) {
          if (!r.ok) {
            var msg =
              data && data.message
                ? String(data.message)
                : 'HTTP ' + r.status;
            throw new Error(msg);
          }
          var quote = mapQuote(data);
          if (!quote) {
            throw new Error('empty');
          }
          return quote;
        });
    });
  }

  function fetchQuotes(type, count) {
    var jobs = [];
    var i;
    for (i = 0; i < count; i += 1) {
      jobs.push(
        fetchOneQuote(type).catch(function () {
          return null;
        })
      );
    }
    return Promise.all(jobs).then(function (results) {
      var quotes = [];
      var seen = Object.create(null);
      results.forEach(function (q) {
        if (!q || !q.text) {
          return;
        }
        // Dedupe identical text from parallel random draws.
        if (seen[q.text]) {
          return;
        }
        seen[q.text] = 1;
        quotes.push(q);
      });
      return quotes;
    });
  }

  function initYiyan(el) {
    if (el.dataset.yiyanBound) {
      return;
    }
    el.dataset.yiyanBound = '1';

    var count = normalizeCount(el.dataset.count);
    var interval = normalizeIntervalMs(el.dataset.interval);
    var type = normalizeType(el.dataset.type);
    var parts = ensureStructure(el);
    var textEl = parts.textEl;
    var fromEl = parts.fromEl;
    var dotsEl = parts.dotsEl;
    var quotes = [];
    var currentIndex = 0;
    var timer = null;

    function showQuote(index) {
      if (!quotes.length || !textEl) {
        return;
      }
      var q = quotes[index % quotes.length];
      textEl.style.opacity = '0';
      setTimeout(function () {
        textEl.textContent = '"' + q.text + '"';
        textEl.style.opacity = '1';
        if (fromEl) {
          fromEl.textContent = q.from ? '—— ' + q.from : '';
        }
      }, 200);

      if (dotsEl) {
        dotsEl.querySelectorAll('.aksrt-yiyan__dot').forEach(function (dot, i) {
          dot.classList.toggle('is-active', i === index % quotes.length);
        });
      }
    }

    function nextQuote() {
      if (quotes.length < 2) {
        return;
      }
      currentIndex = (currentIndex + 1) % quotes.length;
      showQuote(currentIndex);
    }

    function startTimer() {
      if (timer) {
        clearInterval(timer);
        timer = null;
      }
      if (quotes.length > 1) {
        timer = setInterval(nextQuote, interval);
      }
    }

    function buildDots() {
      if (!dotsEl || quotes.length < 2) {
        if (dotsEl) {
          dotsEl.innerHTML = '';
        }
        return;
      }
      dotsEl.innerHTML = '';
      quotes.forEach(function (_, i) {
        var dot = document.createElement('span');
        dot.className = 'aksrt-yiyan__dot' + (i === 0 ? ' is-active' : '');
        dotsEl.appendChild(dot);
      });
    }

    el.addEventListener('mouseenter', function () {
      if (timer) {
        clearInterval(timer);
        timer = null;
      }
    });
    el.addEventListener('mouseleave', function () {
      startTimer();
    });

    fetchQuotes(type, count)
      .then(function (list) {
        quotes = list;
        if (!quotes.length) {
          textEl.textContent = '暂无内容';
          return;
        }
        buildDots();
        showQuote(0);
        startTimer();
      })
      .catch(function () {
        textEl.textContent = '加载失败，请稍后再试';
      });
  }

  document.addEventListener('DOMContentLoaded', function () {
    document.querySelectorAll('[data-aksrt-yiyan]').forEach(initYiyan);
  });
})();