/* 人机验证（自研「一键验证」）—— 服务端见 blog-admin/src/lib/human.ts
 *
 * 交互仿 Cloudflare Turnstile：编辑器底部、`.atk-send-btn`（评论一下）左侧一个
 * 方形勾选框。读者大多数时候无感 —— 浏览器在后台静默算一个 PoW，够了就直接打勾；
 * 信号不足时方框保持可点，用户点一下就通过。
 *
 * 为什么不再用「图形验证码」：用户明确不要「输字符」那种交互。前端已移除图形
 * 验证码入口；服务端 humanGate 的 captcha 兜底仍然保留（不影响），遇到
 * need_captcha 时前端展示可重试的失败态。
 *
 * 通行证按 IP 记在服务端 KV（30 分钟），前端不传任何 token，
 * 所以不需要改 Artalk 客户端。文章页 / 留言页共用本模块。
 *
 * 历史：本逻辑原先内联在 layouts/page/comment.html 里 —— 只有留言页有，
 * 而文章页评论同样走服务端 humanGate → 新访客在文章页会 403。抽成模块
 * 进 page-only bundle 后两处一致。
 */
(function () {
  var BASE = window.rssApiBase ||
    (window.artalkConfig && window.artalkConfig.server) ||
    'https://api.200181.xyz';
  BASE = String(BASE).replace(/\/+$/, '');
  var API = BASE + '/api/v2';

  var DIFFICULTY = 4;
  var PREFIX = new Array(DIFFICULTY + 1).join('0');
  var CHECK_SVG = '<svg viewBox="0 0 24 24"><path d="M5 13l4 4L19 7"/></svg>';

  var started = Date.now();
  var events = 0, honey = '', busy = false;
  var state = 'idle';        // idle | busy | pass | fail
  var failMsg = '';
  var proof = null, autoTried = false;

  // ── 行为信号：人类随手动一下就会有，脚本环境常常一个都没有
  ['mousemove', 'pointerdown', 'keydown', 'keyup', 'input', 'focusin', 'scroll', 'wheel',
    'touchstart', 'click'].forEach(function (ev) {
      document.addEventListener(ev, function () { events++; }, { passive: true });
    });

  function injectCss() {
    if (document.getElementById('atk-human-css')) return;
    var st = document.createElement('style');
    st.id = 'atk-human-css';
    st.textContent =
      /* 容器：与 .atk-send-btn 同高 30px，紧贴其左侧 */
      '.atk-human-tf{display:inline-flex;align-items:center;gap:7px;height:30px;box-sizing:border-box;' +
        'margin-right:8px;padding:0 10px;border:1px solid var(--border-main,#e5e7eb);border-radius:4px;' +
        'background:var(--bg-card,#fafafa);font-size:12px;line-height:1;color:var(--text-main,#4b5563);' +
        'cursor:pointer;user-select:none;white-space:nowrap;flex:none;' +
        'transition:border-color .2s ease,background .2s ease,box-shadow .2s ease}' +
      '.atk-human-tf.is-idle:hover{border-color:var(--theme-main,#07c160);' +
        'box-shadow:0 0 0 3px var(--theme-main-20,rgba(7,193,96,.15))}' +
      '.atk-human-tf.is-busy{cursor:default;opacity:.85}' +
      '.atk-human-tf.is-pass{cursor:default;border-color:var(--theme-main,#07c160);' +
        'background:var(--theme-main-10,rgba(7,193,96,.08))}' +
      '.atk-human-tf.is-fail{cursor:pointer;border-color:#e05a5a;background:rgba(224,90,90,.08);color:#c0392b}' +
      /* 左侧方形勾选框 */
      '.atk-human-tf-box{flex:none;width:18px;height:18px;border-radius:3px;box-sizing:border-box;' +
        'border:1.5px solid #c8ccd4;background:#fff;display:flex;align-items:center;justify-content:center;' +
        'transition:background .2s ease,border-color .2s ease}' +
      '.atk-human-tf.is-pass .atk-human-tf-box{background:var(--theme-main,#07c160);' +
        'border-color:var(--theme-main,#07c160)}' +
      '.atk-human-tf.is-fail .atk-human-tf-box{background:#e05a5a;border-color:#e05a5a;color:#fff;' +
        'font-weight:700;font-size:12px;line-height:1}' +
      '.atk-human-tf-box svg{width:12px;height:12px;display:block}' +
      '.atk-human-tf-box svg path{stroke:#fff;stroke-width:2.6;fill:none;stroke-linecap:round;stroke-linejoin:round}' +
      '.atk-human-tf-spin{width:12px;height:12px;border-radius:50%;box-sizing:border-box;' +
        'border:2px solid var(--theme-main-30,rgba(7,193,96,.3));border-top-color:var(--theme-main,#07c160);' +
        'animation:atkHumanSpin .7s linear infinite}' +
      '@keyframes atkHumanSpin{to{transform:rotate(360deg)}}' +
      '.atk-human-tf-tx{white-space:nowrap}' +
      '[data-theme="dark"] .atk-human-tf{border-color:rgba(255,255,255,.14);background:rgba(255,255,255,.04)}' +
      '[data-theme="dark"] .atk-human-tf-box{border-color:rgba(255,255,255,.28);background:rgba(255,255,255,.08)}' +
      '@media (max-width:640px){.atk-human-tf{padding:0 8px;margin-right:6px}.atk-human-tf-tx{font-size:11px}}' +
      '@media (prefers-reduced-motion:reduce){.atk-human-tf-spin{animation-duration:2s}}';
    document.head.appendChild(st);
  }

  function hex(buf) {
    var b = new Uint8Array(buf), out = '';
    for (var i = 0; i < b.length; i++) out += ('0' + b[i].toString(16)).slice(-2);
    return out;
  }
  function sha256(str) {
    return crypto.subtle.digest('SHA-256', new TextEncoder().encode(str)).then(hex);
  }

  /* 找 nonce 让 sha256(challenge+nonce) 以 N 个 0 开头。
     crypto.subtle 是异步的，逐次 await 的 promise 开销远大于哈希本身：
     所以按 CHUNK 串一条链、每 CHUNK*YIELD_EVERY 次让出一次主线程，
     页面保持流畅，总耗时压到 1 秒上下（全程后台，读者无感）。 */
  var CHUNK = 512, YIELD_EVERY = 8;
  function solve(challenge) {
    var i = 0;
    function step() {
      var chain = Promise.resolve(null);
      var found0 = null;
      var limit = i + CHUNK * YIELD_EVERY;
      while (i < limit && i < 3000000) {
        (function (n) {
          chain = chain.then(function () {
            if (found0 !== null) return found0;      // 已找到 → 后面的直接短路
            return sha256(challenge + n).then(function (h) {
              if (h.slice(0, DIFFICULTY) === PREFIX) { found0 = n; return n; }
              return null;
            });
          });
        })(i++);
      }
      return chain.then(function (found) {
        if (found !== null) return found;
        if (i >= 4000000) return null;
        return new Promise(function (r) { setTimeout(r, 0); }).then(step);
      });
    }
    return step();
  }

  function api(path, body) {
    return fetch(API + path, {
      method: body ? 'POST' : 'GET',
      headers: body ? { 'Content-Type': 'application/json' } : undefined,
      body: body ? JSON.stringify(body) : undefined,
    }).then(function (r) { return r.json().catch(function () { return {}; }); });
  }

  // ── 控件
  function sendBtn() {
    return document.querySelector('.atk-bottom .atk-send-btn') ||
      document.querySelector('.atk-send-btn');
  }
  function editorEl() {
    return document.querySelector('.atk-main-editor');
  }

  /** 把控件插到「评论一下」按钮左侧（同一个 .atk-item 内，天然左邻） */
  function ensureWidget() {
    var btn = sendBtn();
    if (!btn || !btn.parentElement) return null;
    var host = btn.parentElement;
    var w = null;
    for (var i = 0; i < host.children.length; i++) {
      if (host.children[i].classList && host.children[i].classList.contains('atk-human-tf')) {
        w = host.children[i]; break;
      }
    }
    if (!w) {
      w = document.createElement('div');
      w.className = 'atk-human-tf is-idle';
      w.setAttribute('role', 'button');
      w.setAttribute('tabindex', '0');
      w.setAttribute('title', '人机验证');
      w.addEventListener('click', onWidgetClick);
      w.addEventListener('keydown', function (e) {
        if (e.key === 'Enter' || e.key === ' ') { e.preventDefault(); onWidgetClick(); }
      });
      host.insertBefore(w, btn);
      injectCss();
    }
    render(w);
    if (!autoTried) { autoTried = true; setTimeout(function () { run(false); }, 60); }
    return w;
  }

  function onWidgetClick() {
    if (busy || state === 'busy' || state === 'pass') return;
    run(true);          // 点击本身就是强人类信号（服务端 clicked 直接放行）
  }

  function render(w) {
    w = w || ensureWidget();
    if (!w) return;
    var key = state + '|' + failMsg;
    if (w.dataset.hk === key) return;     // 状态没变就别重建 DOM（避免转圈动画被重置）
    w.dataset.hk = key;
    w.className = 'atk-human-tf is-' + state;
    if (state === 'pass') {
      w.innerHTML = '<span class="atk-human-tf-box">' + CHECK_SVG + '</span>' +
        '<span class="atk-human-tf-tx">已通过验证</span>';
    } else if (state === 'busy') {
      w.innerHTML = '<span class="atk-human-tf-box"><span class="atk-human-tf-spin"></span></span>' +
        '<span class="atk-human-tf-tx">验证中…</span>';
    } else if (state === 'fail') {
      w.innerHTML = '<span class="atk-human-tf-box">!</span>' +
        '<span class="atk-human-tf-tx">' + (failMsg || '验证失败，点击重试') + '</span>';
    } else {
      w.innerHTML = '<span class="atk-human-tf-box"></span>' +
        '<span class="atk-human-tf-tx">点击验证</span>';
    }
  }

  function setState(s, msg) {
    state = s;
    if (s === 'fail') failMsg = msg || '';
    render();
  }

  function ensureHoneypot() {
    if (document.getElementById('atk-human-hp')) return;
    var ed = editorEl();
    if (!ed) return;
    var i = document.createElement('input');
    i.id = 'atk-human-hp'; i.type = 'text'; i.tabIndex = -1; i.autocomplete = 'off';
    i.setAttribute('aria-hidden', 'true');
    i.style.cssText = 'position:absolute;left:-9999px;top:0;width:1px;height:1px;opacity:0';
    i.addEventListener('input', function () { honey = i.value; });
    ed.appendChild(i);
  }

  // ── 主流程
  // 证明只算一次并缓存：点「点击验证」复用同一个 nonce 重发（补上 clicked 信号），
  // 所以点击是**瞬间完成**的，不会让访客再等一次算力。
  function ensureProof() {
    if (proof && proof.exp > Date.now() + 5000) return Promise.resolve(proof);
    return api('/human/challenge').then(function (ch) {
      if (!ch || ch.enabled === false || ch.pass) return null;
      return solve(ch.challenge).then(function (nonce) {
        if (nonce === null) return null;
        proof = { challenge: ch.challenge, nonce: nonce, exp: ch.exp, sig: ch.sig };
        return proof;
      });
    });
  }

  function run(clicked) {
    if (busy || state === 'pass') return Promise.resolve();
    busy = true;
    setState('busy');
    return api('/human/status').then(function (st) {
      if (!st || st.enabled === false || st.pass) { setState('pass'); return null; }
      if (!window.crypto || !crypto.subtle) {
        setState('fail', '浏览器不支持验证');
        return null;
      }
      return ensureProof().then(function (pr) {
        if (!pr) { setState('fail', '验证服务不可用'); return null; }
        return api('/human/verify', {
          challenge: pr.challenge, nonce: pr.nonce, exp: pr.exp, sig: pr.sig,
          elapsedMs: Date.now() - started, events: events,
          webdriver: navigator.webdriver === true, honeypot: honey, clicked: !!clicked,
        }).then(function (res) {
          if (res && res.pass) { setState('pass'); return; }
          // need_captcha（高风险：蜜罐被填 / webdriver）不再弹图形验证码，给可重试的失败态
          if (res && res.need_captcha) { setState('fail', '未通过验证，点击重试'); return; }
          // need_click：只是还缺人类信号 —— 这不是错误，回到可点的未验证态即可
          setState('idle');
        });
      });
    }).catch(function () {
      /* 网络异常不打扰读者：回到可点状态，服务端提交时仍有门禁兜底 */
      setState('idle');
    }).then(function () { busy = false; });
  }

  // ── 编辑器会被 Artalk 反复重建（pjax / 回复模式 / 提交后），用 observer 补挂
  var mo = null, moTimer = null;
  function watch() {
    if (mo || typeof MutationObserver === 'undefined' || !document.body) return;
    mo = new MutationObserver(function () {
      if (moTimer) return;
      moTimer = setTimeout(function () {
        moTimer = null;
        var btn = sendBtn();
        if (!btn || !btn.parentElement) return;
        var w = null;
        for (var i = 0; i < btn.parentElement.children.length; i++) {
          if (btn.parentElement.children[i].classList &&
            btn.parentElement.children[i].classList.contains('atk-human-tf')) { w = btn.parentElement.children[i]; break; }
        }
        // 控件丢了 / 挂错位置 / 不在按钮左侧 → 重新挂
        if (!w || w.nextElementSibling !== btn) ensureWidget();
      }, 200);
    });
    mo.observe(document.body, { childList: true, subtree: true });
  }

  function init() {
    // 评论页才有意义；文章页/留言页都有 .comments-area
    if (!document.querySelector('.comments-area')) return;
    started = Date.now(); events = 0; busy = false; proof = null; failMsg = '';
    autoTried = false;
    if (state !== 'pass') state = 'idle';
    ensureHoneypot();
    ensureWidget();     // 挂上即触发一次静默验证（见 ensureWidget 里的 autoTried）
    watch();
  }

  /* 调试/自测钩子（线上留着也无害） */
  window.__humanCheck = {
    state: function () {
      return { state: state, busy: busy, events: events, honey: honey, hasPass: state === 'pass' };
    },
    run: run,
    widget: function () { return document.querySelector('.atk-human-tf'); },
  };

  document.addEventListener('pjax:complete', function () { setTimeout(init, 300); });
  if (document.readyState === 'loading') document.addEventListener('DOMContentLoaded', init);
  else init();
})();