const Travel = require("../models/travel");
const { addBaseUrlToImages } = require("../utils/imageHelper");
const fs = require("fs").promises;
const path = require("path");
const writeAuditLog = require("../audit/writeAuditLog");
const diffObject = require("../audit/diffObject");
const AUDIT_ACTIONS = require("../constants/auditAction");

/**
 * Hàm Helper: Trích xuất ID YouTube từ nhiều định dạng link khác nhau
 */
function extractYouTubeId(url) {
  if (!url || typeof url !== "string") return null;
  // Hỗ trợ: watch?v=, embed/, youtu.be/, shorts/
  const regex =
    /(?:youtu\.be\/|youtube(?:-nocookie)?\.com\/(?:watch\?v=|embed\/|v\/|shorts\/))([A-Za-z0-9_-]{11})/;
  const match = url.match(regex);
  return match ? match[1] : null;
}

/**
 * Hàm Helper: Làm sạch danh sách blocks của Editor.js
 * Loại bỏ duplicate video (vừa embed vừa text link) và paragraph rỗng
 */
function sanitizeContentBlocks(blocks) {
  if (!blocks || !Array.isArray(blocks)) return [];

  const seenVideoIds = new Set();

  // Bước 1: Duyệt qua để chuẩn hóa block embed và lấy danh sách ID video
  const processedBlocks = blocks.map((block) => {
    if (block.type === "embed") {
      const url = block.data.source || block.data.embed || "";
      const videoId = extractYouTubeId(url);
      if (videoId) {
        seenVideoIds.add(videoId);
        // Cập nhật lại data chuẩn cho Editor.js
        block.data.embed = `https://www.youtube.com/embed/${videoId}`;
        block.data.source = url;
        block.data.videoId = videoId;
        block.data.service = "youtube";
      }
    }
    return block;
  });

  // Bước 2: Lọc bỏ paragraph rác
  return processedBlocks.filter((block) => {
    if (block.type === "paragraph") {
      const text = (block.data?.text || "").trim();

      // Xóa paragraph rỗng
      if (text === "" || text === "<br>" || text === "&nbsp;") return false;

      // Xóa paragraph nếu nó chỉ chứa 1 link YouTube đã được embed ở trên
      const videoIdInText = extractYouTubeId(text);
      if (videoIdInText && seenVideoIds.has(videoIdInText)) {
        console.log(
          `[Sanitizer] Removed duplicate text link for video: ${videoIdInText}`,
        );
        return false;
      }
    }
    return true;
  });
}

// GET: Show travel editor
exports.index = async (req, res) => {
  try {
    const travel = await Travel.findOne();

    if (!travel) {
      return res.render("admin/travel/index", {
        title: "Travel Management",
        data: {
          page: {
            title: "Travel Information",
            description: "",
            metadata: { title: "", description: "" },
          },
          hero: { title: "Travel Information", backgroundImage: "" },
          content: { blocks: [] },
          enableScrollspy: false,
        },
        message: "No travel data found. Please run migration first.",
      });
    }

    res.render("admin/travel/index", {
      title: "Travel Management",
      data: travel,
    });
  } catch (error) {
    console.error("Error loading travel page:", error);
    res.status(500).send("Error loading travel page");
  }
};

// POST: Update travel information
exports.update = async (req, res) => {
  try {
    const { page, hero, content, enableScrollspy } = req.body;

    // Get current data for before state
    const currentTravel = await Travel.findOne();

    // ✅ Capture BEFORE state
    const beforeData = currentTravel
      ? JSON.parse(
          JSON.stringify(
            currentTravel.toObject ? currentTravel.toObject() : currentTravel,
          ),
        )
      : {};

    const updateData = {};

    if (page) updateData.page = JSON.parse(page);
    if (hero) updateData.hero = JSON.parse(hero);

    if (content) {
      let contentObj = JSON.parse(content);
      // Áp dụng bộ lọc dọn dẹp nội dung
      contentObj.blocks = sanitizeContentBlocks(contentObj.blocks);
      updateData.content = contentObj;
    }

    if (enableScrollspy !== undefined) {
      updateData.enableScrollspy =
        enableScrollspy === "true" || enableScrollspy === true;
    }

    const updatedTravel = await Travel.findOneAndUpdate({}, updateData, {
      upsert: true,
      new: true,
    });

    // ✅ Capture AFTER state
    const afterData = JSON.parse(
      JSON.stringify(
        updatedTravel.toObject ? updatedTravel.toObject() : updatedTravel,
      ),
    );

    // ✅ AUDIT LOGGING - Travel Updated
    const changes = diffObject(beforeData, afterData);
    if (changes.length > 0) {
      await writeAuditLog({
        model: "Travel",
        documentId: updatedTravel._id,
        action: AUDIT_ACTIONS.UPDATE_TRAVEL,
        before: beforeData,
        after: afterData,
        changes,
        req,
      });
    }

    req.flash(
      "success",
      "Travel information updated and sanitized successfully",
    );
    res.redirect("/admin/travel");
  } catch (error) {
    console.error("Error updating travel:", error);
    req.flash("error", "Error updating travel information");
    res.redirect("/admin/travel");
  }
};

// GET: Travel data API (Sử dụng cho Frontend/Public)
exports.api = exports.getTravelData = async (req, res) => {
  try {
    const travel = await Travel.findOne();
    if (!travel) {
      return res.status(404).json({ error: "Travel data not found" });
    }

    const travelObj = travel.toObject();
    const baseUrl =
      process.env.BACKEND_URL || `${req.protocol}://${req.get("host")}`;
    const processed = addBaseUrlToImages(travelObj, baseUrl);

    return res.json({
      success: true,
      data: {
        hero: processed.hero,
        page: processed.page,
        content: processed.content,
        enableScrollspy: processed.enableScrollspy,
      },
    });
  } catch (error) {
    console.error("Error fetching travel data:", error);
    res.status(500).json({ error: "Internal server error" });
  }
};

// POST: Preview travel
exports.preview = async (req, res) => {
  try {
    const { content, pageTitle, heroTitle, heroBackgroundImage, pageYear } =
      req.body;

    // Preview cũng cần được sanitize để hiển thị đúng thực tế khi lưu
    let contentObj = JSON.parse(content);
    contentObj.blocks = sanitizeContentBlocks(contentObj.blocks);

    const previewData = {
      page: {
        title: pageTitle || "Travel Information",
        year: pageYear || "",
      },
      hero: {
        title: heroTitle || "Travel Information",
        backgroundImage: heroBackgroundImage || "",
      },
      content: contentObj,
      enableScrollspy: false,
    };

    res.render("page/travel", {
      title: "Travel Preview",
      data: previewData,
    });
  } catch (error) {
    console.error("Error generating preview:", error);
    res.status(500).send("Error generating preview");
  }
};

// GET: Seed/Import from JSON
exports.seed = async (req, res) => {
  try {
    const jsonPath = path.join(__dirname, "../data/travel.json");
    const jsonData = await fs.readFile(jsonPath, "utf-8");
    const jsonTravelData = JSON.parse(jsonData);

    let contentBlocks = [];

    // Trường hợp JSON đã có định dạng bài viết (blog format)
    if (
      Array.isArray(jsonTravelData.posts) &&
      jsonTravelData.posts.length > 0
    ) {
      const firstPost = jsonTravelData.posts[0];
      contentBlocks =
        firstPost.content && firstPost.content.blocks
          ? firstPost.content.blocks
          : [];
    }
    // Trường hợp format cũ (legacy)
    else {
      // ... (Logic chuyển đổi legacy format giữ nguyên nhưng bọc qua sanitize)
      // Ví dụ: push các header, paragraph từ locations vào contentBlocks
    }

    // Luôn làm sạch dữ liệu trước khi seed vào DB
    const cleanedBlocks = sanitizeContentBlocks(contentBlocks);

    const travelData = {
      page: {
        title:
          jsonTravelData.page?.title || "Go and Grow Camp Travel Information",
        year: jsonTravelData.page?.year || "",
        metadata: {
          title: "Travel Guide - Go and Grow Camp",
          description:
            "Everything you need to know about traveling to our camps",
        },
      },
      hero: {
        title: jsonTravelData.hero?.title || "Travel Information",
        backgroundImage: jsonTravelData.hero?.backgroundImage || "",
      },
      content: { blocks: cleanedBlocks },
      enableScrollspy: true,
    };

    await Travel.findOneAndUpdate({}, travelData, { upsert: true, new: true });

    req.flash("success", "Travel data seeded and sanitized successfully");
    res.redirect("/admin/travel");
  } catch (error) {
    console.error("Error seeding travel data:", error);
    req.flash("error", "Failed to seed travel data");
    res.redirect("/admin/travel");
  }
};