require('dotenv').config(); // Load environment variables
const express = require('express');
const path = require('path');
const fs = require('fs');
const { marked } = require('marked');
const nodemailer = require('nodemailer');
const hljs = require('highlight.js');
const { format } = require('date-fns'); // To format dates in a proper XML format

const app = express();

// Set options for marked to use highlight.js for syntax highlighting
marked.setOptions({
    highlight: function (code, language) {
        // Check if the language is valid
        const validLanguage = hljs.getLanguage(language) ? language : 'plaintext';
        return hljs.highlight(validLanguage, code).value;
    }
});

// Set EJS as templating engine
app.set('view engine', 'ejs');
app.set('views', path.join(__dirname, 'views'));

// Middleware to parse URL-encoded bodies (form submissions)
app.use(express.urlencoded({ extended: false }));

// Serve static files (CSS, Images)
app.use(express.static(path.join(__dirname, 'public')));

// Function to load and parse markdown files and extract lead
function loadMarkdownWithLead(file) {
    const markdownContent = fs.readFileSync(path.join(__dirname, 'markdown', file), 'utf-8');

    let lead = '';
    let contentMarkdown = markdownContent;

    // Detect and extract the lead section
    const leadKeyword = '<!-- lead -->';
    if (contentMarkdown.includes(leadKeyword)) {
        const [beforeLead, afterLead] = contentMarkdown.split(leadKeyword);

        // Extract the first paragraph after the lead keyword
        lead = afterLead.split('\n').find(line => line.trim() !== '').trim();

        // Remove the lead from the main content
        contentMarkdown = beforeLead + afterLead.replace(lead, '').trim();
    }

    // Convert markdown to HTML
    const contentHtml = marked.parse(contentMarkdown);

    return { contentHtml, lead };
}

// Function to convert a title (with spaces and special characters) into a URL-friendly slug (with dashes)
function titleToSlug(title) {
    return title
        .toLowerCase()            // Convert to lowercase
        .replace(/[^a-z0-9\s-]/g, '') // Remove all non-alphanumeric characters except spaces and dashes
        .replace(/\s+/g, '-');    // Replace spaces with dashes
}

// Function to convert a slug (with dashes) back into a readable title (with spaces)
function slugToTitle(slug) {
    return slug.replace(/-/g, ' ');
}

// Function to load all blog posts with pagination support
function getAllBlogPosts(page = 1, postsPerPage = 5) {
    const blogFiles = fs.readdirSync(path.join(__dirname, 'markdown')).filter(file => file.endsWith('.md'));

    // Paginate the results
    const totalPosts = blogFiles.length;
    const totalPages = Math.ceil(totalPosts / postsPerPage);
    const start = (page - 1) * postsPerPage;
    const end = start + postsPerPage;

    const paginatedFiles = blogFiles.slice(start, end);

    const blogPosts = paginatedFiles.map(file => {
        const title = file.replace('.md', '').replace(/-/g, ' '); // Keep original casing for title
        const slug = titleToSlug(title); // Convert title to slug (lowercase)

        // Get the last modified date of the markdown file
        const stats = fs.statSync(path.join(__dirname, 'markdown', file));
        const dateCreated = new Date(stats.birthtime); // Use birthtime for last modification time

        // Format the date
        const formattedDate = dateCreated.toLocaleDateString('en-US', {
            year: 'numeric',
            month: 'long',
            day: 'numeric'
        });

        return {
            title, // Original casing title
            slug,
            date: formattedDate // Include the formatted date
        };
    });

    return { blogPosts, totalPages };
}

// Home Route (Blog Home with Pagination)
app.get('/', (req, res) => {
    const page = parseInt(req.query.page) || 1;

    if (page < 1) {
        return res.redirect(req.hostname);
    }

    const postsPerPage = 5; // Set how many posts to display per page

    const { blogPosts, totalPages } = getAllBlogPosts(page, postsPerPage);

    res.render('index', {
        title: 'Raven Scott Blog',
        blogPosts,
        currentPage: page,
        totalPages
    });
});

// About Route
app.get('/about', (req, res) => {
    res.render('about', { title: 'About Raven Scott' });
});

// Display the Request a Quote form
app.get('/contact', (req, res) => {
    res.render('contact', { title: 'Contact Raven Scott', msg: undefined });
});

// Handle contact form submission
app.post('/contact', (req, res) => {
    const { name, email, subject, message } = req.body;

    // Validate form inputs (basic example)
    if (!name || !email || !subject || !message) {
        return res.render('contact', { title: 'Contact Raven Scott', msg: 'All fields are required.' });
    }

    // Create email content
    const output = `
        <p>You have a new contact request from <strong>${name}</strong>.</p>
        <h3>Contact Details</h3>
        <ul>
            <li><strong>Name:</strong> ${name}</li>
            <li><strong>Email:</strong> ${email}</li>
            <li><strong>Subject:</strong> ${subject}</li>
        </ul>
        <h3>Message</h3>
        <p>${message}</p>
    `;

    // Set up Nodemailer transporter
    let transporter = nodemailer.createTransport({
        host: process.env.SMTP_HOST,
        port: process.env.SMTP_PORT,
        secure: false, // true for 465, false for other ports
        auth: {
            user: process.env.EMAIL_USER, // Email user from environment variables
            pass: process.env.EMAIL_PASS, // Email password from environment variables
        },
        tls: {
            rejectUnauthorized: false,
        },
    });

    // Set up email options
    let mailOptions = {
        from: `"${name}" <quote@node-geeks.com>`,
        to: process.env.RECEIVER_EMAIL, // Your email address to receive contact form submissions
        subject: subject,
        html: output,
    };

    // Send email
    transporter.sendMail(mailOptions, (error, info) => {
        if (error) {
            console.error(error);
            return res.render('contact', { title: 'Contact Raven Scott', msg: 'An error occurred. Please try again.' });
        } else {
            console.log('Email sent: ' + info.response);
            return res.render('contact', { title: 'Contact Raven Scott', msg: 'Your message has been sent successfully!' });
        }
    });
});

// Blog Post Route
app.get('/blog/:slug', (req, res) => {
    const slug = req.params.slug;
    const markdownFile = fs.readdirSync(path.join(__dirname, 'markdown'))
        .find(file => titleToSlug(file.replace('.md', '')) === slug);

    if (markdownFile) {
        const originalTitle = markdownFile.replace('.md', ''); // Original title with casing
        const blogPosts = getAllBlogPosts();
        const { contentHtml, lead } = loadMarkdownWithLead(markdownFile);

        res.render('blog-post', {
            title: originalTitle, // Use the original title with casing
            content: contentHtml,
            lead: lead,
            blogPosts
        });
    } else {
        res.redirect('/'); // Redirect to the home page if the blog post is not found
    }
});

// Sitemap Route
// Sitemap Route
app.get('/sitemap.xml', (req, res) => {
    const hostname = req.headers.host || 'http://localhost'; // Ensure this is your site URL in production
    const blogFiles = fs.readdirSync(path.join(__dirname, 'markdown'))
        .filter(file => file.endsWith('.md'))
        .sort((a, b) => {
            const statA = fs.statSync(path.join(__dirname, 'markdown', a)).birthtime;
            const statB = fs.statSync(path.join(__dirname, 'markdown', b)).birthtime;
            return statB - statA; // Sort in descending order (latest first)
        });

    // Static URLs (e.g., homepage, about, contact)
    const staticUrls = [
        { url: '/', changefreq: 'weekly', priority: 1.0 },
        { url: '/about', changefreq: 'monthly', priority: 0.8 },
        { url: '/contact', changefreq: 'monthly', priority: 0.8 }
    ];

    // Dynamic URLs (e.g., blog posts)
    const blogUrls = blogFiles.map(file => {
        const title = file.replace('.md', '');
        const slug = titleToSlug(title);

        // Get the last modified date of the markdown file
        const stats = fs.statSync(path.join(__dirname, 'markdown', file));
        const lastModifiedDate = format(new Date(stats.birthtime), 'yyyy-MM-dd');

        return {
            url: `/blog/${slug}`,
            lastmod: lastModifiedDate,
            changefreq: 'monthly',
            priority: 0.9
        };
    });

    // Combine static and dynamic URLs
    const urls = [...staticUrls, ...blogUrls];

    // Generate the XML for the sitemap
    let sitemap = `<?xml version="1.0" encoding="UTF-8"?>\n<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">\n`;
    urls.forEach(({ url, lastmod, changefreq, priority }) => {
        sitemap += `  <url>\n`;
        sitemap += `    <loc>https://${hostname}${url}</loc>\n`;
        if (lastmod) {
            sitemap += `    <lastmod>${lastmod}</lastmod>\n`;
        }
        sitemap += `    <changefreq>${changefreq}</changefreq>\n`;
        sitemap += `    <priority>${priority}</priority>\n`;
        sitemap += `  </url>\n`;
    });
    sitemap += `</urlset>`;

    // Set the content type to XML and send the response
    res.header('Content-Type', 'application/xml');
    res.send(sitemap);
});


// RSS Feed Route
app.get('/rss', (req, res) => {
    const hostname = req.headers.host || 'http://localhost'; // Adjust for production if needed
    const blogFiles = fs.readdirSync(path.join(__dirname, 'markdown'))
        .filter(file => file.endsWith('.md'))
        .sort((a, b) => {
            const statA = fs.statSync(path.join(__dirname, 'markdown', a)).birthtime;
            const statB = fs.statSync(path.join(__dirname, 'markdown', b)).birthtime;
            return statB - statA; // Sort in descending order (latest first)
        });

    // Build RSS feed
    let rssFeed = `<?xml version="1.0" encoding="UTF-8" ?>\n<rss version="2.0">\n<channel>\n`;
    rssFeed += `<title>Raven Scott Blog</title>\n`;
    rssFeed += `<link>https://${hostname}</link>\n`;
    rssFeed += `<description>This is the RSS feed for Raven Scott's blog.</description>\n`;

    // Generate RSS items for each blog post
    blogFiles.forEach(file => {
        const title = file.replace('.md', '');
        const slug = titleToSlug(title);

        // Get the last modified date of the markdown file
        const stats = fs.statSync(path.join(__dirname, 'markdown', file));
        const lastModifiedDate = new Date(stats.birthtime).toUTCString(); // Use UTC date for RSS

        // Load and parse markdown content to extract a lead or description
        const { lead } = loadMarkdownWithLead(file);

        // RSS item for each post
        rssFeed += `<item>\n`;
        rssFeed += `<title>${title}</title>\n`;
        rssFeed += `<link>https://${hostname}/blog/${slug}</link>\n`;
        rssFeed += `<description>${lead || 'Read the full post on the blog.'}</description>\n`;
        rssFeed += `<pubDate>${lastModifiedDate}</pubDate>\n`;
        rssFeed += `<guid>https://${hostname}/blog/${slug}</guid>\n`;
        rssFeed += `</item>\n`;
    });

    rssFeed += `</channel>\n</rss>`;

    // Set content type to XML and send the RSS feed
    res.header('Content-Type', 'application/rss+xml');
    res.send(rssFeed);
});


// Global 404 handler for any other unmatched routes
app.use((req, res) => {
    res.redirect('/'); // Redirect to the home page for any 404 error
});

// ================================
// Server Listening
// ================================
const PORT = process.env.PORT || 8899;
app.listen(PORT, () => {
    console.log(`Server running on http://localhost:${PORT}`);
});