import dotenv from "dotenv";
import express from "express";
import cors from "cors";
import session from "express-session";
import fs from "fs-extra";
import path from "path";
import { fileURLToPath } from "url";
import { v4 as uuidv4 } from "uuid";
import multer from "multer";

// Load environment variables
dotenv.config();
import {
    authenticateUser,
    getUserByUsername,
    changeUserPassword,
} from "./auth.js";
import {
    getAllThemes,
    getActiveTheme,
    setActiveTheme,
    createCustomTheme,
    updateCustomTheme,
    deleteCustomTheme,
    exportTheme,
} from "./themes.js";

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

const app = express();
app.set("trust proxy", 1); // Trust the first proxy (Caddy) so secure cookies work behind HTTPS termination
const PORT = process.env.PORT || 3001;

// Paths
const POSTS_DIR = path.resolve(
    __dirname,
    process.env.POSTS_DIR || "../public/posts",
);
const INDEX_FILE = path.join(POSTS_DIR, "index.json");

// Multer Storage Configuration
const storage = multer.diskStorage({
    destination: async function (req, file, cb) {
        // Determine folder based on slug
        let folder = "uploads"; // Default
        if (req.query.slug) {
            // Clean the slug just in case, though it should be safe if generated by us
            const cleanSlug = req.query.slug.replace(/[^a-z0-9-]/gi, "");
            folder = path.join(cleanSlug, "images");
        }

        const uploadPath = path.join(POSTS_DIR, folder);
        try {
            await fs.ensureDir(uploadPath);
            cb(null, uploadPath);
        } catch (err) {
            cb(err);
        }
    },
    filename: function (req, file, cb) {
        // Keep original filename but ensure uniqueness if needed? 
        // For now, simple filename is better for markdown readability.
        // We'll replace spaces with dashes.
        const cleanName = file.originalname.replace(/[^a-z0-9.]/gi, "-").toLowerCase();
        cb(null, cleanName); // Overwrites if exists, which might be desired behavior for updating images
    },
});

const upload = multer({ storage: storage });


// Middleware
app.use(
    cors({
        origin: [
            "http://localhost:5173",
            "https://goonblog.thevakhovske.eu.org",
        ],
        credentials: true, // Enable cookies
    }),
);
app.use(express.json());
app.use(express.urlencoded({ extended: true }));

// Serve static files from POSTS_DIR so images are accessible
// Access images via /api/media-files/SLUG/images/FILENAME.jpg
// We use /api/media-files to avoid conflict with /api/posts routes and to align with API_BASE
app.use("/api/media-files", express.static(POSTS_DIR));

// Session configuration
app.use(
    session({
        secret:
            process.env.SESSION_SECRET ||
            "gooneral-wheelchair-secret-key-change-in-production",
        resave: false,
        saveUninitialized: false,
        name: "gooneral-session",
        cookie: {
            secure: true, // HTTPS required
            httpOnly: true,
            maxAge: 24 * 60 * 60 * 1000, // 24 hours
            sameSite: "lax", // Changed from 'strict' to 'lax'
        },
    }),
);

// Ensure posts directory exists
await fs.ensureDir(POSTS_DIR);

// Authentication middleware
function requireAuth(req, res, next) {
    if (req.session && req.session.user && req.session.user.role === "admin") {
        return next();
    }
    return res.status(401).json({ error: "Authentication required" });
}

// Check if user is authenticated
function isAuthenticated(req, res, next) {
    req.isAuthenticated = !!(req.session && req.session.user);
    req.user = req.session?.user || null;
    next();
}

// Helper function to generate index.json
async function generateIndex() {
    try {
        const files = await fs.readdir(POSTS_DIR);
        // We only care about root level .md files for the index
        const mdFiles = files.filter((f) => f.endsWith(".md"));
        await fs.writeJSON(INDEX_FILE, mdFiles, { spaces: 2 });
        console.log(`Index updated: ${mdFiles.length} posts`);
        return mdFiles;
    } catch (error) {
        console.error("Error generating index:", error);
        throw error;
    }
}

// Helper function to parse post metadata
function parsePostMetadata(content) {
    const titleMatch = content.match(/title:\s*(.*)/);
    const descMatch = content.match(/desc:\s*(.*)/);
    const tagsMatch = content.match(/tags:\s*(.*)/);
    const hiddenMatch = content.match(/hidden:\s*(true|false)/);

    return {
        title: titleMatch ? titleMatch[1].trim() : "Untitled",
        description: descMatch ? descMatch[1].trim() : "",
        tags: tagsMatch ? tagsMatch[1].split(",").map((tag) => tag.trim()) : [],
        hidden: hiddenMatch ? hiddenMatch[1] === "true" : false,
    };
}

// Helper function to generate filename from title
function generateFilename(title) {
    // Create date-based filename similar to existing pattern
    const date = new Date();
    const dateStr = date.toISOString().slice(0, 10).replace(/-/g, "");
    const slug = title
        .toLowerCase()
        .replace(/[^a-z0-9]+/g, "-")
        .replace(/^-|-$/g, "")
        .slice(0, 30);

    return slug ? `${dateStr}-${slug}.md` : `${dateStr}.md`;
}

// Helper to generate just the SLUG part (without date/extension if possible, or matches filename structure)
// For internal consistency, we should try to match how valid posts are named.
// But if user creates a "temporary" slug from title, we use that.
function getSlugFromTitle(title) {
    const date = new Date();
    const dateStr = date.toISOString().slice(0, 10).replace(/-/g, "");
    const slugText = title
        .toLowerCase()
        .replace(/[^a-z0-9]+/g, "-")
        .replace(/^-|-$/g, "")
        .slice(0, 30);
    return `${dateStr}-${slugText}`;
}


// Authentication Routes

// POST /api/auth/login - Login
app.post("/api/auth/login", async (req, res) => {
    try {
        const { username, password } = req.body;

        if (!username || !password) {
            return res
                .status(400)
                .json({ error: "Username and password are required" });
        }

        const user = await authenticateUser(username, password);
        if (!user) {
            return res
                .status(401)
                .json({ error: "Invalid username or password" });
        }

        // Store user in session
        req.session.user = user;
        console.log("Login successful - Session ID:", req.sessionID);
        console.log("Login successful - Stored user:", req.session.user);

        // Manually save the session to ensure it's persisted
        req.session.save((err) => {
            if (err) {
                console.error("Session save error:", err);
                return res
                    .status(500)
                    .json({ error: "Failed to save session" });
            }

            console.log("Session saved successfully");
            res.json({
                success: true,
                user: {
                    username: user.username,
                    role: user.role,
                },
            });
        });
    } catch (error) {
        console.error("Login error:", error);
        res.status(500).json({ error: "Login failed" });
    }
});

// POST /api/auth/logout - Logout
app.post("/api/auth/logout", (req, res) => {
    req.session.destroy((err) => {
        if (err) {
            return res.status(500).json({ error: "Logout failed" });
        }
        res.clearCookie("gooneral-session"); // Use the same name as configured
        res.json({ success: true, message: "Logged out successfully" });
    });
});

// GET /api/auth/me - Get current user
app.get("/api/auth/me", isAuthenticated, (req, res) => {
    console.log("Auth check - Session ID:", req.sessionID);
    console.log("Auth check - Session user:", req.session?.user);
    console.log("Auth check - Is authenticated:", req.isAuthenticated);

    if (req.isAuthenticated) {
        res.json({
            user: {
                username: req.user.username,
                role: req.user.role,
            },
        });
    } else {
        res.json({ user: null });
    }
});

// POST /api/auth/change-password - Change password
app.post("/api/auth/change-password", requireAuth, async (req, res) => {
    try {
        const { currentPassword, newPassword } = req.body;

        if (!currentPassword || !newPassword) {
            return res.status(400).json({
                error: "Current password and new password are required",
            });
        }

        if (newPassword.length < 6) {
            return res.status(400).json({
                error: "New password must be at least 6 characters long",
            });
        }

        const result = await changeUserPassword(
            req.user.username,
            currentPassword,
            newPassword,
        );

        if (result.success) {
            res.json({ success: true, message: result.message });
        } else {
            res.status(400).json({ error: result.message });
        }
    } catch (error) {
        console.error("Change password error:", error);
        res.status(500).json({ error: "Failed to change password" });
    }
});

// MEDIA ROUTES

// POST /api/upload - Upload file
// Query param: slug (optional, for organization)
app.post("/api/upload", requireAuth, upload.single("file"), (req, res) => {
    if (!req.file) {
        return res.status(400).json({ error: "No file uploaded" });
    }

    const { slug } = req.query;
    let urlPath = "";

    if (slug) {
        // Should match the folder structure logic in storage config
        const cleanSlug = slug.replace(/[^a-z0-9-]/gi, "");
        urlPath = `/media-files/${cleanSlug}/images/${req.file.filename}`;
    } else {
        urlPath = `/media-files/uploads/${req.file.filename}`;
    }

    res.json({
        success: true,
        url: urlPath,
        filename: req.file.filename,
        originalName: req.file.originalname,
    });
});

// GET /api/media - List files
// Query param: slug (optional)
app.get("/api/media", requireAuth, async (req, res) => {
    try {
        const { slug } = req.query;
        let targetDir = "";

        if (slug) {
            const cleanSlug = slug.replace(/[^a-z0-9-]/gi, "");
            targetDir = path.join(POSTS_DIR, cleanSlug, "images");
        } else {
            // If no slug, maybe list all? Or list 'uploads'?
            // Providing a 'root' param or just listing everything might be expensive.
            // Let's list 'uploads' by default or require a slug properly.
            // For a "Media Manager", we might want to scan ALL folders.

            // For now, let's implement listing a specific slug's images.
            // If we want a global manager, we can return a tree.

            // Simple approach: list all directories in POSTS_DIR that are directories, and then their images.
            // That's complex. Let's just return empty if no slug, or implement logic later for global view.

            // Let's default to "uploads" if no slug, OR if a special flag "all" is present, we scan?
            targetDir = path.join(POSTS_DIR, "uploads");
        }

        if (!(await fs.pathExists(targetDir))) {
            return res.json([]);
        }

        const files = await fs.readdir(targetDir);
        const mediaFiles = [];

        for (const file of files) {
            const stats = await fs.stat(path.join(targetDir, file));
            if (stats.isFile() && /\.(jpg|jpeg|png|gif|webp|svg)$/i.test(file)) {
                const slugPart = slug ? slug.replace(/[^a-z0-9-]/gi, "") : "uploads";
                // If slug was passed, url is /media-files/SLUG/images/FILE
                // If no slug (using uploads), url is /media-files/uploads/FILE

                const url = slug
                    ? `/media-files/${slugPart}/images/${file}`
                    : `/media-files/uploads/${file}`;

                mediaFiles.push({
                    name: file,
                    url: url,
                    size: stats.size,
                    date: stats.mtime,
                });
            }
        }

        // Sort by newest
        mediaFiles.sort((a, b) => b.date - a.date);

        res.json(mediaFiles);
    } catch (err) {
        console.error("Error listing media:", err);
        res.status(500).json({ error: "Failed to list media" });
    }
});

// DELETE /api/media - Delete file
app.delete("/api/media", requireAuth, async (req, res) => {
    try {
        const { path: relativePath } = req.body; // e.g. "/media-files/slug/images/file.jpg"
        if (!relativePath) return res.status(400).json({ error: "Path is required" });

        // Security check: ensure path is within POSTS_DIR
        // relativePath typically starts with /media-files/
        const cleanPath = relativePath.replace(/^\/media-files\//, "");
        const fullPath = path.join(POSTS_DIR, cleanPath);

        // Prevent directory traversal
        if (!fullPath.startsWith(POSTS_DIR)) {
            return res.status(403).json({ error: "Invalid path" });
        }

        if (await fs.pathExists(fullPath)) {
            await fs.remove(fullPath);
            res.json({ success: true });
        } else {
            res.status(404).json({ error: "File not found" });
        }

    } catch (err) {
        console.error("Delete media error:", err);
        res.status(500).json({ error: "Failed to delete media" });
    }
});

// API Routes continue...

// GET /api/posts - Get all posts with metadata
app.get("/api/posts", async (req, res) => {
    try {
        const files = await generateIndex();
        const posts = [];

        for (const filename of files) {
            const filePath = path.join(POSTS_DIR, filename);
            const content = await fs.readFile(filePath, "utf8");
            const metadata = parsePostMetadata(content);
            const slug = filename.replace(".md", "");

            posts.push({
                slug,
                filename,
                ...metadata,
                createdAt: (await fs.stat(filePath)).birthtime,
                updatedAt: (await fs.stat(filePath)).mtime,
            });
        }

        // Sort by creation date, newest first
        posts.sort((a, b) => new Date(b.createdAt) - new Date(a.createdAt));

        // Filter out hidden posts for non-admins
        const isAdmin = req.session && req.session.user && req.session.user.role === "admin";
        const visiblePosts = posts.filter(post => isAdmin || !post.hidden);

        res.json(visiblePosts);
    } catch (error) {
        console.error("Error fetching posts:", error);
        res.status(500).json({ error: "Failed to fetch posts" });
    }
});

// GET /api/posts/:slug - Get specific post
app.get("/api/posts/:slug", async (req, res) => {
    try {
        const { slug } = req.params;
        const filename = `${slug}.md`;
        const filePath = path.join(POSTS_DIR, filename);

        if (!(await fs.pathExists(filePath))) {
            return res.status(404).json({ error: "Post not found" });
        }

        const content = await fs.readFile(filePath, "utf8");
        const metadata = parsePostMetadata(content);
        const stats = await fs.stat(filePath);

        // Access control for hidden posts
        const isAdmin = req.session && req.session.user && req.session.user.role === "admin";
        if (metadata.hidden && !isAdmin) {
            // Return 404 to hide existence, or 403 if we want to be explicit.
            // 404 is safer for "hidden" content.
            return res.status(404).json({ error: "Post not found" });
        }

        res.json({
            slug,
            filename,
            ...metadata,
            content,
            createdAt: stats.birthtime,
            updatedAt: stats.mtime,
        });
    } catch (error) {
        console.error("Error fetching post:", error);
        res.status(500).json({ error: "Failed to fetch post" });
    }
});

// POST /api/posts - Create new post
app.post("/api/posts", requireAuth, async (req, res) => {
    try {
        const { title, description, content, tags, hidden } = req.body;

        if (!title || !content) {
            return res
                .status(400)
                .json({ error: "Title and content are required" });
        }

        // Generate filename
        const filename = generateFilename(title);
        const filePath = path.join(POSTS_DIR, filename);

        // Check if file already exists
        if (await fs.pathExists(filePath)) {
            return res
                .status(409)
                .json({ error: "Post with similar title already exists" });
        }

        // Format the post content
        let postContent = "";
        postContent += `title: ${title}\n`;
        if (description) postContent += `desc: ${description}\n`;
        if (tags && tags.length > 0)
            postContent += `tags: ${tags.join(", ")}\n`;
        if (hidden) postContent += `hidden: true\n`;
        postContent += "\n" + content;

        // Write the file
        await fs.writeFile(filePath, postContent, "utf8");

        // Update index
        await generateIndex();

        const slug = filename.replace(".md", "");
        const stats = await fs.stat(filePath);

        res.status(201).json({
            slug,
            filename,
            title,
            description: description || "",
            tags: tags || [],
            content: postContent,
            createdAt: stats.birthtime,
            updatedAt: stats.mtime,
        });
    } catch (error) {
        console.error("Error creating post:", error);
        res.status(500).json({ error: "Failed to create post" });
    }
});

// PUT /api/posts/:slug - Update existing post
app.put("/api/posts/:slug", requireAuth, async (req, res) => {
    try {
        const { slug } = req.params;
        const { title, description, content, tags, hidden } = req.body;

        const oldFilename = `${slug}.md`;
        const oldFilePath = path.join(POSTS_DIR, oldFilename);

        if (!(await fs.pathExists(oldFilePath))) {
            return res.status(404).json({ error: "Post not found" });
        }

        if (!title || !content) {
            return res
                .status(400)
                .json({ error: "Title and content are required" });
        }

        // Generate new filename if title changed
        const newFilename = generateFilename(title);
        const newFilePath = path.join(POSTS_DIR, newFilename);

        // Format the post content
        let postContent = "";
        postContent += `title: ${title}\n`;
        if (description) postContent += `desc: ${description}\n`;
        if (tags && tags.length > 0)
            postContent += `tags: ${tags.join(", ")}\n`;
        if (hidden) postContent += `hidden: true\n`;
        postContent += "\n" + content;

        // Write to new file
        await fs.writeFile(newFilePath, postContent, "utf8");

        // If filename changed, remove old file
        if (oldFilename !== newFilename) {
            await fs.remove(oldFilePath);
            // IMPORTANT: If we rename the post, should we verify if images folder usage needs update?
            // Currently images are stored in /slug/images/. 
            // If the slug (filename) depends on the title, changing title changes slug.
            // We should rename the image folder too!

            const oldSlug = slug;
            const newSlug = newFilename.replace(".md", "");

            const oldImgDir = path.join(POSTS_DIR, oldSlug, "images");
            const newImgDir = path.join(POSTS_DIR, newSlug, "images");

            if (await fs.pathExists(oldImgDir)) {
                await fs.move(oldImgDir, newImgDir, { overwrite: true });
            }
        }

        // Update index
        await generateIndex();

        const newSlug = newFilename.replace(".md", "");
        const stats = await fs.stat(newFilePath);

        res.json({
            slug: newSlug,
            filename: newFilename,
            title,
            description: description || "",
            tags: tags || [],
            content: postContent,
            createdAt: stats.birthtime,
            updatedAt: stats.mtime,
        });
    } catch (error) {
        console.error("Error updating post:", error);
        res.status(500).json({ error: "Failed to update post" });
    }
});

// DELETE /api/posts/:slug - Delete post
app.delete("/api/posts/:slug", requireAuth, async (req, res) => {
    try {
        const { slug } = req.params;
        const filename = `${slug}.md`;
        const filePath = path.join(POSTS_DIR, filename);

        if (!(await fs.pathExists(filePath))) {
            return res.status(404).json({ error: "Post not found" });
        }

        await fs.remove(filePath);

        // Removing associated images folder
        const imgDir = path.join(POSTS_DIR, slug, "images");
        if (await fs.pathExists(imgDir)) {
            await fs.remove(imgDir);
        }
        // Also remove parent folder if it was created just for this? 
        // Structure is POSTS_DIR/slug/images. 
        // We should remove POSTS_DIR/slug
        const slugDir = path.join(POSTS_DIR, slug);
        if (await fs.pathExists(slugDir)) {
            await fs.remove(slugDir);
        }

        await generateIndex();

        res.json({ message: "Post deleted successfully" });
    } catch (error) {
        console.error("Error deleting post:", error);
        res.status(500).json({ error: "Failed to delete post" });
    }
});

// Theme API Routes
// GET /api/themes - Get all themes
app.get("/api/themes", async (req, res) => {
    try {
        const themesData = await getAllThemes();
        res.json(themesData);
    } catch (error) {
        console.error("Error fetching themes:", error);
        res.status(500).json({ error: "Failed to fetch themes" });
    }
});

// GET /api/themes/active - Get active theme
app.get("/api/themes/active", async (req, res) => {
    try {
        const activeTheme = await getActiveTheme();
        res.json(activeTheme);
    } catch (error) {
        console.error("Error fetching active theme:", error);
        res.status(500).json({ error: "Failed to fetch active theme" });
    }
});

// PUT /api/themes/active - Set active theme
app.put("/api/themes/active", requireAuth, async (req, res) => {
    try {
        const { themeId } = req.body;

        if (!themeId) {
            return res.status(400).json({ error: "Theme ID is required" });
        }

        const activeTheme = await setActiveTheme(themeId);
        res.json({ success: true, theme: activeTheme });
    } catch (error) {
        console.error("Error setting active theme:", error);
        res.status(400).json({ error: error.message });
    }
});

// POST /api/themes - Create custom theme
app.post("/api/themes", requireAuth, async (req, res) => {
    try {
        const themeData = req.body;
        const newTheme = await createCustomTheme(themeData);
        res.status(201).json(newTheme);
    } catch (error) {
        console.error("Error creating theme:", error);
        res.status(400).json({ error: error.message });
    }
});

// PUT /api/themes/:themeId - Update custom theme
app.put("/api/themes/:themeId", requireAuth, async (req, res) => {
    try {
        const { themeId } = req.params;
        const themeData = req.body;

        const updatedTheme = await updateCustomTheme(themeId, themeData);
        res.json(updatedTheme);
    } catch (error) {
        console.error("Error updating theme:", error);
        res.status(400).json({ error: error.message });
    }
});

// DELETE /api/themes/:themeId - Delete custom theme
app.delete("/api/themes/:themeId", requireAuth, async (req, res) => {
    try {
        const { themeId } = req.params;
        await deleteCustomTheme(themeId);
        res.json({ success: true, message: "Theme deleted successfully" });
    } catch (error) {
        console.error("Error deleting theme:", error);
        res.status(400).json({ error: error.message });
    }
});

// GET /api/themes/:themeId/export - Export theme
app.get("/api/themes/:themeId/export", requireAuth, async (req, res) => {
    try {
        const { themeId } = req.params;
        const themeData = await exportTheme(themeId);

        res.setHeader("Content-Type", "application/json");
        res.setHeader(
            "Content-Disposition",
            `attachment; filename="theme-${themeId}.json"`,
        );
        res.json(themeData);
    } catch (error) {
        console.error("Error exporting theme:", error);
        res.status(400).json({ error: error.message });
    }
});

// Health check endpoint
app.get("/api/health", (req, res) => {
    res.json({ status: "OK", timestamp: new Date().toISOString() });
});

// SERVE FRONTEND (SSR-lite for Meta Tags)
const DIST_DIR = path.join(__dirname, "../dist");
const INDEX_HTML = path.join(DIST_DIR, "index.html");

// Serve static assets with aggressive caching
// Vite assets are hashed (e.g., index.h4124j.js), so they are immutable.
app.use(
    "/assets",
    express.static(path.join(DIST_DIR, "assets"), {
        maxAge: "1y", // 1 year
        immutable: true,
        setHeaders: (res, path) => {
            res.setHeader("Cache-Control", "public, max-age=31536000, immutable");
        },
    }),
);

// Serve other static files (favicon, robots, etc.) with default caching
app.use(express.static(DIST_DIR, { index: false }));

// Helper to inject meta tags
const injectMetaTags = async (html, metadata, url) => {
    let injected = html;

    // Default values
    const title = metadata.title || "Gooneral Wheelchair";
    const description = metadata.description || "A blog about stuff.";
    const image = metadata.image || "https://goonblog.thevakhovske.eu.org/og-image.jpg"; // Fallback image

    // Replace Title
    injected = injected.replace(/<title>.*<\/title>/, `<title>${title}</title>`);

    // Meta Tags to Inject
    const metaTags = `
    <meta property="og:title" content="${title}" />
    <meta property="og:description" content="${description}" />
    <meta property="og:image" content="${image}" />
    <meta property="og:url" content="${url}" />
    <meta property="og:type" content="article" />
    <meta name="twitter:card" content="summary_large_image" />
    <meta name="twitter:title" content="${title}" />
    <meta name="twitter:description" content="${description}" />
    <meta name="twitter:image" content="${image}" />
    `;

    // Inject before </head>
    return injected.replace("</head>", `${metaTags}</head>`);
};


// Handle Post Routes for SSR
app.get("/posts/:slug", async (req, res) => {
    try {
        const { slug } = req.params;
        const filename = `${slug}.md`;
        const filePath = path.join(POSTS_DIR, filename);

        // Read index.html template
        let html = await fs.readFile(INDEX_HTML, "utf8");

        if (await fs.pathExists(filePath)) {
            const content = await fs.readFile(filePath, "utf8");
            const metadata = parsePostMetadata(content);

            // Try to find the first image in the content for the OG image
            const imageMatch = content.match(/!\[.*?\]\((.*?)\)/);
            let imageUrl = null;
            if (imageMatch) {
                imageUrl = imageMatch[1];
                // Ensure absolute URL
                if (imageUrl.startsWith("/")) {
                    imageUrl = `${req.protocol}://${req.get("host")}${imageUrl}`;
                }
            }

            // Check access (Hidden posts)
            // If hidden and not admin, serve standard index.html (SPA will handle 404/auth check client-side)
            // OR we can pretend it doesn't exist to bots.
            const isAdmin = req.session && req.session.user && req.session.user.role === "admin";
            if (metadata.hidden && !isAdmin) {
                // Determine behavior: 
                // If we send raw index.html, client app loads and shows "Not Found" or "Login".
                // We'll just send raw index.html without generic meta tags? Or default tags?
                // Let's send default tags to avoid leaking info.
                res.send(html);
                return;
            }

            const pageMetadata = {
                title: metadata.title,
                description: metadata.description,
                image: imageUrl
            };

            const finalHtml = await injectMetaTags(html, pageMetadata, `${req.protocol}://${req.get("host")}${req.originalUrl}`);
            res.send(finalHtml);
        } else {
            // Post not found - serve SPA to handle 404
            res.send(html);
        }
    } catch (err) {
        console.error("SSR Error:", err);
        // Fallback to serving static file if something fails
        res.sendFile(INDEX_HTML);
    }
});

// Catch-all route for SPA
app.get("*", async (req, res) => {
    // For other routes (e.g. /, /admin, /login), serve index.html
    // We can also inject default meta tags here if we want.
    try {
        if (await fs.pathExists(INDEX_HTML)) {
            res.sendFile(INDEX_HTML);
        } else {
            res.status(404).send("Frontend build not found");
        }

    } catch (err) {
        res.status(500).send("Server Error");
    }
});

// Generate initial index on startup
await generateIndex();

app.listen(PORT, () => {
    console.log(`🚀 Backend server running on http://localhost:${PORT}`);
    console.log(`📁 Posts directory: ${POSTS_DIR}`);
});