// content.js - Extracts page content and converts to Markdown
// Guard against double-injection (MV3 scripting.executeScript can fire multiple times)
if (window.__memosClipperLoaded) { /* skip */ } else {
window.__memosClipperLoaded = true;

(function () {
  // ── Turndown-lite: a minimal but solid HTML→Markdown converter ──────────────
  function htmlToMarkdown(element) {
    const clone = element.cloneNode(true);

    // Remove unwanted elements — comprehensive list covering real-world sites
    const removeSelectors = [
      // Semantic structural chrome
      'script', 'style', 'noscript', 'template',
      'nav', 'header', 'footer', 'aside',
      // ARIA roles for chrome
      '[role="navigation"]', '[role="banner"]', '[role="complementary"]',
      '[role="contentinfo"]', '[role="search"]', '[role="toolbar"]',
      '[role="menubar"]', '[role="menu"]', '[role="dialog"]',
      // Common class/id patterns for site chrome
      '[class*="navbar"]', '[class*="nav-bar"]', '[class*="site-nav"]',
      '[class*="site-header"]', '[class*="site-footer"]',
      '[class*="page-header"]', '[class*="page-footer"]',
      '[id*="navbar"]', '[id*="site-nav"]', '[id*="site-header"]', '[id*="site-footer"]',
      // Ads and tracking
      '[class*="advertisement"]', '[class*="advert"]', '[class*=" ad-"]',
      '[class*="google-ad"]', '[class*="sponsored"]',
      '[id*="advertisement"]', '[id*="google_ad"]',
      // Cookie banners, popups, overlays
      '[class*="cookie"]', '[id*="cookie"]',
      '[class*="consent"]', '[id*="consent"]',
      '[class*="gdpr"]', '[id*="gdpr"]',
      '[class*="popup"]', '[class*="modal"]', '[class*="overlay"]',
      '[class*="banner"]', '[id*="banner"]',
      // Social / share widgets
      '[class*="share-bar"]', '[class*="social-bar"]', '[class*="share-buttons"]',
      '[class*="sharing"]',
      // Subscription / newsletter prompts
      '[class*="newsletter"]', '[class*="subscribe"]',
      // Comments sections
      '[id="comments"]', '[class*="comments-section"]', '[id*="disqus"]',
      // Related / recommended articles
      '[class*="related-posts"]', '[class*="recommended"]', '[class*="more-articles"]',
      // Sidebar
      '[class*="sidebar"]', '[id*="sidebar"]',
      // Print/hidden
      '[hidden]', '[aria-hidden="true"]',
    ].join(', ');

    clone.querySelectorAll(removeSelectors).forEach((el) => el.remove());

    // Also remove elements that are visually hidden via inline style
    clone.querySelectorAll('[style*="display:none"],[style*="display: none"],[style*="visibility:hidden"]')
      .forEach((el) => el.remove());

    return nodeToMd(clone).replace(/\n{3,}/g, "\n\n").trim();
  }

  function nodeToMd(node, ctx = { listDepth: 0, ordered: false, index: 0 }) {
    if (node.nodeType === Node.TEXT_NODE) {
      return node.textContent.replace(/\s+/g, " ");
    }
    if (node.nodeType !== Node.ELEMENT_NODE) return "";

    const tag = node.tagName.toLowerCase();
    const children = () =>
      Array.from(node.childNodes)
        .map((c) => nodeToMd(c, ctx))
        .join("");

    switch (tag) {
      case "h1": return `\n\n# ${children().trim()}\n\n`;
      case "h2": return `\n\n## ${children().trim()}\n\n`;
      case "h3": return `\n\n### ${children().trim()}\n\n`;
      case "h4": return `\n\n#### ${children().trim()}\n\n`;
      case "h5": return `\n\n##### ${children().trim()}\n\n`;
      case "h6": return `\n\n###### ${children().trim()}\n\n`;
      case "p":  return `\n\n${children().trim()}\n\n`;
      case "br": return "  \n";
      case "hr": return "\n\n---\n\n";

      case "strong":
      case "b": return `**${children()}**`;
      case "em":
      case "i": return `_${children()}_`;
      case "s":
      case "del": return `~~${children()}~~`;
      case "code": {
        const text = node.textContent;
        return text.includes("`") ? `\`\`${text}\`\`` : `\`${text}\``;
      }
      case "pre": {
        const codeEl = node.querySelector("code");
        const lang = codeEl
          ? (codeEl.className.match(/language-(\S+)/) || [])[1] || ""
          : "";
        const text = (codeEl || node).textContent;
        return `\n\n\`\`\`${lang}\n${text}\n\`\`\`\n\n`;
      }
      case "blockquote": return `\n\n${children()
        .trim()
        .split("\n")
        .map((l) => `> ${l}`)
        .join("\n")}\n\n`;

      case "a": {
        const href = node.getAttribute("href") || "";
        const text = children().trim();
        if (!text) return href;
        try {
          const abs = new URL(href, location.href).href;
          return `[${text}](${abs})`;
        } catch {
          return `[${text}](${href})`;
        }
      }

      case "img": {
        const src = node.getAttribute("src") || "";
        const alt = node.getAttribute("alt") || "";
        try {
          const abs = new URL(src, location.href).href;
          return `![${alt}](${abs})`;
        } catch {
          return src ? `![${alt}](${src})` : "";
        }
      }

      case "ul": {
        const lines = Array.from(node.children)
          .map((li) => `${"  ".repeat(ctx.listDepth)}- ${nodeToMd(li, { ...ctx, listDepth: ctx.listDepth + 1 }).trim()}`)
          .join("\n");
        return `\n\n${lines}\n\n`;
      }
      case "ol": {
        const lines = Array.from(node.children)
          .map((li, i) => `${"  ".repeat(ctx.listDepth)}${i + 1}. ${nodeToMd(li, { ...ctx, listDepth: ctx.listDepth + 1 }).trim()}`)
          .join("\n");
        return `\n\n${lines}\n\n`;
      }
      case "li": return children();

      case "table": return convertTable(node);

      case "figure": {
        const img = node.querySelector("img");
        const caption = node.querySelector("figcaption");
        let md = img ? nodeToMd(img, ctx) : children();
        if (caption) md += `\n*${caption.textContent.trim()}*`;
        return `\n\n${md}\n\n`;
      }

      // skip presentational / hidden
      case "svg":
      case "canvas":
      case "video":
      case "audio":
      case "iframe":
      case "button":
      case "input":
      case "select":
      case "textarea":
      case "form":
      case "nav":
      case "header":
      case "footer":
      case "aside":
        return "";

      default:
        return children();
    }
  }

  function convertTable(table) {
    const rows = Array.from(table.querySelectorAll("tr"));
    if (!rows.length) return "";
    const toRow = (tr) =>
      "| " +
      Array.from(tr.querySelectorAll("th,td"))
        .map((c) => c.textContent.trim().replace(/\|/g, "\\|"))
        .join(" | ") +
      " |";
    const header = toRow(rows[0]);
    const sep =
      "| " +
      Array.from(rows[0].querySelectorAll("th,td"))
        .map(() => "---")
        .join(" | ") +
      " |";
    const body = rows.slice(1).map(toRow).join("\n");
    return `\n\n${header}\n${sep}\n${body}\n\n`;
  }

  // ── Extract images from HTML ────────────────────────────────────────────────
  function extractImages(element) {
    const seen = new Set();
    const imgs = Array.from(element.querySelectorAll("img"));
    return imgs
      .filter((img) => {
        const src = img.getAttribute("src") || "";
        if (!src) return false;
        // skip tiny icons / tracking pixels by rendered size
        const w = img.naturalWidth || img.width || 0;
        const h = img.naturalHeight || img.height || 0;
        if (w > 0 && w < 32 && h > 0 && h < 32) return false;
        // skip 1x1 gif trackers
        if (src.startsWith("data:image/gif")) return false;
        return true;
      })
      .map((img) => {
        const src = img.getAttribute("src") || "";
        let abs = src;
        try { abs = new URL(src, location.href).href; } catch {}
        return { src: abs, alt: img.getAttribute("alt") || "" };
      })
      .filter((img) => {
        if (seen.has(img.src)) return false;
        seen.add(img.src);
        return true;
      });
  }

  // ── Message handler ─────────────────────────────────────────────────────────
  chrome.runtime.onMessage.addListener((msg, _sender, sendResponse) => {
    if (msg.action === "getContent") {
      try {
        let markdown = "";
        let images = [];
        let title = document.title || location.href;

        if (msg.mode === "selection") {
          const sel = window.getSelection();
          if (sel && sel.rangeCount > 0) {
            const frag = sel.getRangeAt(0).cloneContents();
            const div = document.createElement("div");
            div.appendChild(frag);
            markdown = htmlToMarkdown(div);
            images = extractImages(div);
          } else {
            markdown = "";
          }
        } else {
          // full page — prefer article/main, fall back to body
          const root =
            document.querySelector("article") ||
            document.querySelector("main") ||
            document.querySelector('[role="main"]') ||
            document.body;
          markdown = htmlToMarkdown(root);
          images = extractImages(root);
        }

        // Prepend source line
        const sourceNote = `> Source: [${title}](${location.href})\n\n`;
        markdown = sourceNote + markdown;

        sendResponse({ ok: true, markdown, images, title, url: location.href });
      } catch (e) {
        sendResponse({ ok: false, error: e.message });
      }
      return true; // async
    }
  });
})();
} // end guard