// ==UserScript==
// @name         小红书无水印下载器 by星月云
// @namespace    https://github.com/JoeanAmier/XHS-Downloader
// @version      2.0.0
// @description  纯浏览器端小红书作品下载：从 window.__INITIAL_STATE__ 解析图片/视频直链，直接 fetch+blob 落盘。
// @author       WorkBuddy
// @match        *://www.xiaohongshu.com/*
// @match        *://www.rednote.com/*
// @grant        GM_setValue
// @grant        GM_getValue
// @grant        GM_setClipboard
// @grant        unsafeWindow
// @run-at       document-idle
// @license GPL-2.0
// ==/UserScript==

(function () {
  "use strict";

  const GM = typeof unsafeWindow !== "undefined" ? unsafeWindow : window;
  const DOC = document;

  const SITE = location.hostname.includes("rednote")
    ? "rednote"
    : "xiaohongshu";

  const STORE = {
    imageFmt: GM_getValue("xhs_image_fmt", "jpeg"), // jpeg / webp / png / heic / avif
    videoPref: GM_getValue("xhs_video_pref", "resolution"), // resolution / bitrate / size
    autoScroll: GM_getValue("xhs_auto_scroll", false),
    scrollTimes: GM_getValue("xhs_scroll_times", 30),
    delay: GM_getValue("xhs_delay", 400), // 作品之间的间隔(ms)，防限流
  };

  const IMG_REGEX = {
    xiaohongshu: /https?:\/\/sns-webpic-qc\.xhscdn\.com\/\d+\/[0-9a-z]+\/(\S+)!/,
    rednote: /https?:\/\/sns-web-i10\.rednotecdn\.com\/\d+\/[0-9a-z]+\/(\S+)!/,
  };
  const PREF_KEY = { resolution: "height", bitrate: "videoBitrate", size: "size" };

  /* ---------------- 工具 ---------------- */
  const $ = (s, r = DOC) => r.querySelector(s);
  const $$ = (s, r = DOC) => Array.from(r.querySelectorAll(s));
  const sleep = (ms) => new Promise((r) => setTimeout(r, ms));

  function getState() {
    try {
      return GM.__INITIAL_STATE__ || null;
    } catch (e) {
      return null;
    }
  }
  function safeGet(o, p) {
    return p.split(".").reduce((a, k) => (a == null ? undefined : a[k]), o);
  }
  function safeArr(o, p) {
    const v = safeGet(o, p);
    return Array.isArray(v) ? v : [];
  }

  // 收集本页所有笔记对象（noteCard 形态）
  function collectNotes() {
    const s = getState();
    const notes = [];
    if (!s) return notes;
    const push = (it) => it && it.noteCard && notes.push(it.noteCard);
    safeArr(s.feed, "feeds._rawValue").forEach(push);
    safeArr(s.search, "feeds._rawValue").forEach(push);
    safeArr(s.user, "notes._rawValue").forEach((it) => push({ noteCard: it }));
    const board = safeGet(s, "board.boardFeedsMap._rawValue");
    if (board)
      Object.values(board).forEach((b) =>
        safeArr(b, "notes").forEach((it) =>
          it && it.noteCard ? notes.push(it.noteCard) : it && it.noteId && notes.push(it)
        )
      );
    const nd = safeGet(s, "noteData.data.noteData");
    if (nd) notes.push(nd);
    const ndm = safeGet(s, "note.noteDetailMap");
    if (ndm) Object.values(ndm).forEach((v) => v && v.note && notes.push(v.note));
    // 去重
    const seen = new Set();
    return notes.filter((n) => {
      const id = n.noteId || n.id;
      if (!id || seen.has(id)) return false;
      seen.add(id);
      return true;
    });
  }

  function extractCurrentNoteId() {
    const m = location.pathname.match(/\/(?:explore|discovery\/item)\/([0-9a-zA-Z]+)/);
    return m ? m[1] : null;
  }

  // 优先精确匹配详情页作品，避免误取信息流卡片（卡片往往只有 1 张封面图）
  function getDetailNote() {
    const s = getState();
    if (!s) return null;
    const id = extractCurrentNoteId();
    if (id) {
      const n = safeGet(s, `note.noteDetailMap.${id}.note`);
      if (n) return n;
    }
    const nd = safeGet(s, "noteData.data.noteData");
    if (nd) return nd;
    const ndm = safeGet(s, "note.noteDetailMap");
    if (ndm) {
      const vals = Object.values(ndm)
        .map((v) => (v && v.note ? v.note : null))
        .filter(Boolean);
      if (vals.length) return vals[vals.length - 1];
    }
    return null;
  }

  // 当前详情页作品：带重试，等待页面 __INITIAL_STATE__ 水合完成（避免只拿到 1 张封面的卡片）
  async function currentNote() {
    for (let i = 0; i < 15; i++) {
      const n = getDetailNote();
      if (n && (Array.isArray(n.imageList) ? n.imageList.length : 0) >= 1) return n;
      if (n && n.video) return n;
      await sleep(300);
    }
    return getDetailNote();
  }

  function getMeta(note) {
    if (!note) return { title: "", author: "", id: "" };
    return {
      title: note.title || note.displayTitle || "",
      author:
        (note.user && (note.user.nickname || note.user.nickName)) ||
        note.nickName ||
        "",
      id: note.noteId || note.id || "",
    };
  }

  function sanitize(name) {
    return (
      (name || "")
        .replace(/[\\/:*?"<>|\r\n\t]+/g, "_")
        .replace(/\s+/g, " ")
        .trim()
        .slice(0, 60) || "xhs"
    );
  }
  function baseName(note) {
    const m = getMeta(note);
    return `${sanitize(m.title)}_${sanitize(m.author)}_${m.id}`.replace(
      /_+/g,
      "_"
    );
  }

  /* ---------------- 直链生成 ---------------- */
  // 为每张图生成多个候选直链，按优先级依次尝试，最大化成功率
  function imageCandidates(note, fmt) {
    const imgs = note.imageList || [];
    const re = IMG_REGEX[SITE] || IMG_REGEX.xiaohongshu;
    const out = [];
    imgs.forEach((item, i) => {
      const url = item.urlDefault || item.url || item.urlPre;
      if (!url) return;
      let token = null;
      const m = url.match(re);
      if (m && m[1]) token = m[1];
      else token = url.split("/").slice(5).join("/").split("!")[0];
      const candidates = [];
      if (token) {
        candidates.push(`https://ci.xiaohongshu.com/${token}?imageView2/format/${fmt}`);
        candidates.push(`https://sns-img-bd.xhscdn.com/${token}`);
      }
      // 原始 CDN 直链（去掉 ! 变换后缀，取未处理的原图；同域最稳，作为兜底）
      const raw = url.split("!")[0];
      if (raw && raw.startsWith("http")) candidates.push(raw);
      if (candidates.length) out.push({ index: i + 1, candidates });
    });
    return out;
  }

  function videoUrl(note, pref) {
    try {
      const key = safeGet(note, "video.consumer.originVideoKey");
      if (key) return `https://sns-video-bd.xhscdn.com/${key}`;
      const streams = Object.values(
        safeGet(note, "video.media.stream") || {}
      ).flat();
      if (!streams.length) return null;
      const k = PREF_KEY[pref] || "height";
      streams.sort((a, b) => (b[k] || 0) - (a[k] || 0));
      return streams[0].backupUrls?.[0] || streams[0].masterUrl || null;
    } catch (e) {
      return null;
    }
  }

  /* ---------------- 下载核心 ---------------- */
  let busy = false;

  // link 可为字符串或候选数组，按顺序尝试每个地址
  async function downloadFile(link, name, retries = 3) {
    const urls = Array.isArray(link) ? link : [link];
    for (const u of urls) {
      for (let i = 1; i <= retries; i++) {
        try {
          const res = await fetch(u, {
            method: "GET",
            headers: {
              accept: "image/avif,image/webp,image/apng,image/*,*/*;q=0.8",
              "accept-language": "zh-CN,zh;q=0.9",
            },
            referrerPolicy: "no-referrer",
          });
          if (!res.ok) {
            console.warn(`下载失败 ${res.status} ${u} (第${i}次)`);
            continue;
          }
          const blob = await res.blob();
          if (!blob || blob.size === 0) {
            console.warn(`空文件 ${u}`);
            continue;
          }
          triggerDownload(name, blob);
          return true;
        } catch (e) {
          console.warn(`下载异常 ${u}`, e);
        }
        await sleep(300);
      }
    }
    return false;
  }

  function triggerDownload(name, blob) {
    const url = URL.createObjectURL(blob);
    const a = DOC.createElement("a");
    a.href = url;
    a.download = name;
    DOC.body.appendChild(a);
    a.click();
    a.remove();
    setTimeout(() => URL.revokeObjectURL(url), 2000);
  }

  async function downloadNote(note) {
    const name = baseName(note);
    if (note.type === "video") {
      const u = videoUrl(note, STORE.videoPref);
      if (u) {
        if (await downloadFile([u], `${name}.mp4`))
          toast(`视频已下载：${name}`);
        else toast(`视频下载失败：${name}`, true);
      } else toast(`视频地址解析失败：${name}`, true);
    } else {
      const imgs = imageCandidates(note, STORE.imageFmt);
      if (!imgs.length) {
        toast(`未找到图片：${name}`, true);
        return;
      }
      let ok = 0;
      for (const im of imgs) {
        setCnt(`下载图片 ${im.index}/${imgs.length}`);
        if (await downloadFile(im.candidates, `${name}_${im.index}.${STORE.imageFmt}`))
          ok++;
        await sleep(200);
      }
      toast(`图片下载完成：${ok}/${imgs.length} 张 — ${name}`);
    }
    await sleep(STORE.delay);
  }

  /* ---------------- 自动滚动加载更多 ---------------- */
  async function autoScroll(times) {
    toast(`滚动加载中（${times} 次）…`);
    for (let i = 0; i < times; i++) {
      window.scrollTo(0, DOC.body.scrollHeight);
      await sleep(350 + Math.random() * 250);
    }
    window.scrollTo(0, 0);
    await sleep(300);
  }

  /* ---------------- UI ---------------- */
  let panel, toastEl;

  function buildUI() {
    const css = `
      #xhs-dl2{position:fixed;top:12px;right:12px;z-index:999999;width:280px;background:#fff;
        border:1px solid #ff2e4d33;border-radius:12px;box-shadow:0 6px 24px #0002;
        font:13px/1.5 -apple-system,"PingFang SC","Microsoft YaHei",sans-serif;color:#222;}
      #xhs-dl2 .hd{display:flex;align-items:center;gap:8px;padding:10px 12px;cursor:move;
        background:linear-gradient(90deg,#ff2e4d,#ff7a45);color:#fff;border-radius:12px 12px 0 0;font-weight:600;}
      #xhs-dl2 .bd{padding:10px 12px;display:flex;flex-direction:column;gap:8px;}
      #xhs-dl2 .row{display:flex;gap:6px;}
      #xhs-dl2 button{flex:1;border:none;border-radius:8px;padding:8px 6px;cursor:pointer;
        background:#ff2e4d;color:#fff;font-size:12px;font-weight:600;}
      #xhs-dl2 button.alt{background:#f2f2f2;color:#333;}
      #xhs-dl2 button:disabled{opacity:.5;cursor:not-allowed;}
      #xhs-dl2 select,#xhs-dl2 input[type=number]{border:1px solid #ddd;border-radius:6px;padding:4px;font-size:12px;}
      #xhs-dl2 label{font-size:12px;color:#555;display:flex;align-items:center;gap:6px;}
      #xhs-dl2 .cnt{font-size:12px;color:#ff2e4d;font-weight:600;min-height:16px;}
      #xhs-dl2 textarea{width:100%;height:70px;resize:vertical;border:1px solid #ddd;border-radius:8px;
        padding:6px;font:11px/1.4 monospace;box-sizing:border-box;}
      #xhs-toast2{position:fixed;top:20px;left:50%;transform:translateX(-50%);z-index:1000000;
        background:#222d;color:#fff;padding:8px 16px;border-radius:20px;font:13px sans-serif;opacity:0;
        transition:opacity .25s;pointer-events:none;max-width:80vw;text-align:center;}
      #xhs-toast2.show{opacity:1;} #xhs-toast2.err{background:#c0392bdd;}`;
    const style = DOC.createElement("style");
    style.textContent = css;
    DOC.head.appendChild(style);

    panel = DOC.createElement("div");
    panel.id = "xhs-dl2";
    panel.innerHTML = `
      <div class="hd">小红书无水印下载器 by星月云</div>
      <div class="bd">
        <div class="cnt" id="xhs-cnt">就绪</div>
        <div class="row">
          <button id="xhs-one">下载本篇</button>
          <button id="xhs-all" class="alt">下载本页全部</button>
        </div>
        <label>图片格式
          <select id="xhs-fmt">
            <option value="jpeg">JPEG</option><option value="webp">WEBP</option>
            <option value="png">PNG</option><option value="heic">HEIC</option>
            <option value="avif">AVIF</option>
          </select>
        </label>
        <label>视频偏好
          <select id="xhs-vpref">
            <option value="resolution">分辨率</option>
            <option value="bitrate">码率</option>
            <option value="size">体积</option>
          </select>
        </label>
        <label><input type="checkbox" id="xhs-auto"> 自动滚动加载</label>
        <label>滚动次数 <input type="number" id="xhs-st" min="1" max="200" value="${STORE.scrollTimes}"></label>
        <div class="row">
          <button id="xhs-copy" class="alt">复制本页链接</button>
        </div>
      </div>`;
    DOC.body.appendChild(panel);

    toastEl = DOC.createElement("div");
    toastEl.id = "xhs-toast2";
    DOC.body.appendChild(toastEl);

    // 初始化控件值
    $("#xhs-fmt").value = STORE.imageFmt;
    $("#xhs-vpref").value = STORE.videoPref;
    $("#xhs-auto").checked = STORE.autoScroll;
    $("#xhs-st").value = STORE.scrollTimes;

    $("#xhs-fmt").onchange = (e) => {
      STORE.imageFmt = e.target.value;
      GM_setValue("xhs_image_fmt", STORE.imageFmt);
    };
    $("#xhs-vpref").onchange = (e) => {
      STORE.videoPref = e.target.value;
      GM_setValue("xhs_video_pref", STORE.videoPref);
    };
    $("#xhs-auto").onchange = (e) => {
      STORE.autoScroll = e.target.checked;
      GM_setValue("xhs_auto_scroll", STORE.autoScroll);
    };
    $("#xhs-st").onchange = (e) => {
      STORE.scrollTimes = +e.target.value || 30;
      GM_setValue("xhs_scroll_times", STORE.scrollTimes);
    };

    $("#xhs-one").onclick = async () => {
      if (busy) return;
      busy = true;
      setCnt("识别作品中…");
      const n = await currentNote();
      if (!n) {
        busy = false;
        return toast("未识别到当前作品，请刷新页面后重试", true);
      }
      setCnt("下载本篇中…");
      await downloadNote(n);
      setCnt("本篇下载完成");
      busy = false;
    };

    $("#xhs-all").onclick = async () => {
      if (busy) return;
      if ($("#xhs-auto").checked) await autoScroll(+$("#xhs-st").value || 30);
      const notes = collectNotes();
      if (!notes.length) return toast("本页未识别到作品", true);
      busy = true;
      let ok = 0;
      for (let i = 0; i < notes.length; i++) {
        setCnt(`下载中 ${i + 1}/${notes.length}`);
        await downloadNote(notes[i]);
        ok++;
      }
      setCnt(`完成：共 ${ok} 个作品`);
      busy = false;
    };

    $("#xhs-copy").onclick = () => {
      const links = collectNotes()
        .map((n) => {
          const id = n.noteId || n.id;
          const tk = n.xsecToken;
          return id
            ? `https://www.xiaohongshu.com/explore/${id}${
                tk ? "?xsec_token=" + encodeURIComponent(tk) : ""
              }`
            : null;
        })
        .filter(Boolean);
      if (!links.length) return toast("无链接可复制", true);
      GM_setClipboard(links.join("\n"), "text");
      toast(`已复制 ${links.length} 条链接`);
    };

    makeDraggable(panel, $(".hd", panel));
  }

  function setCnt(t) {
    const el = $("#xhs-cnt");
    if (el) el.textContent = t;
  }
  let toastTimer;
  function toast(msg, err) {
    if (!toastEl) return;
    toastEl.textContent = msg;
    toastEl.className = "show" + (err ? " err" : "");
    clearTimeout(toastTimer);
    toastTimer = setTimeout(() => (toastEl.className = ""), 2400);
  }
  function makeDraggable(el, handle) {
    let sx, sy, ox, oy, drag = false;
    handle.onmousedown = (e) => {
      drag = true;
      sx = e.clientX;
      sy = e.clientY;
      const r = el.getBoundingClientRect();
      ox = r.left;
      oy = r.top;
      e.preventDefault();
    };
    DOC.onmousemove = (e) => {
      if (!drag) return;
      el.style.left = ox + (e.clientX - sx) + "px";
      el.style.top = oy + (e.clientY - sy) + "px";
      el.style.right = "auto";
    };
    DOC.onmouseup = () => (drag = false);
  }

  /* ---------------- 启动 ---------------- */
  function init() {
    if (!DOC.body) return setTimeout(init, 400);
    buildUI();
    if (/xiaohongshu\.com\/(?:explore|discovery\/item)\//.test(location.href)) {
      setTimeout(() => setCnt("已进入作品页，点“下载本篇”"), 600);
    }
  }
  init();
})();