const express = require('express');
const https = require('https');
const fs = require('fs');
const path = require('path');
const os = require('os');
const { createReport } = require('docx-templates');
const cors = require('cors');

const app = express();
const PORT = process.env.PORT || 3000;
const HTTPS_PORT = process.env.HTTPS_PORT || 3443;
const USE_HTTPS = process.env.USE_HTTPS === 'true' || false;

// SSL-Zertifikate laden (falls vorhanden)
let sslOptions = null;
try {
    const sslKeyPath = path.join(__dirname, 'ssl', 'key.pem');
    const sslCertPath = path.join(__dirname, 'ssl', 'cert.pem');
    
    if (fs.existsSync(sslKeyPath) && fs.existsSync(sslCertPath)) {
        sslOptions = {
            key: fs.readFileSync(sslKeyPath),
            cert: fs.readFileSync(sslCertPath)
        };
        console.log('🔒 SSL-Zertifikate gefunden und geladen');
    }
} catch (error) {
    console.log('⚠️ SSL-Zertifikate nicht gefunden - läuft nur über HTTP');
}

// Helper-Funktion für Base URL
function getBaseUrl(req) {
    const protocol = req.secure || req.headers['x-forwarded-proto'] === 'https' ? 'https' : 'http';
    const host = req.get('host');
    
    // Falls kein Host-Header, versuche lokale IP zu ermitteln
    if (!host) {
        const port = req.secure ? HTTPS_PORT : PORT;
        return `${protocol}://localhost:${port}`;
    }
    
    return `${protocol}://${host}`;
}

// Funktion um verfügbare Netzwerk-Interfaces zu ermitteln
function getNetworkInterfaces() {
    const os = require('os');
    const interfaces = os.networkInterfaces();
    const addresses = [];
    
    for (const name in interfaces) {
        for (const iface of interfaces[name]) {
            if (iface.family === 'IPv4' && !iface.internal) {
                addresses.push(iface.address);
            }
        }
    }
    
    return addresses;
}
app.use(cors());
app.use(express.json());
app.use(express.static('public'));

// Template-Ordner erstellen falls nicht vorhanden
const templatesDir = path.join(__dirname, 'templates');
const outputDir = path.join(__dirname, 'output');

if (!fs.existsSync(templatesDir)) {
    fs.mkdirSync(templatesDir, { recursive: true });
}

if (!fs.existsSync(outputDir)) {
    fs.mkdirSync(outputDir, { recursive: true });
}

// Einfache WebDAV-ähnliche Datei-Routen (ohne Authentifizierung)
app.use('/webdav/output', express.static(outputDir, {
    setHeaders: (res, path) => {
        res.set('DAV', '1');
        res.set('Allow', 'GET, PUT, DELETE, PROPFIND, MKCOL');
        res.set('MS-Author-Via', 'DAV');
    }
}));

app.use('/webdav/templates', express.static(templatesDir, {
    setHeaders: (res, path) => {
        res.set('DAV', '1');
        res.set('Allow', 'GET, PUT, DELETE, PROPFIND, MKCOL');
        res.set('MS-Author-Via', 'DAV');
    }
}));

// WebDAV PUT Support für Template-Upload
app.put('/webdav/templates/:filename', express.raw({limit: '50mb', type: '*/*'}), (req, res) => {
    try {
        const filename = req.params.filename;
        const filePath = path.join(templatesDir, filename);
        
        // Nur DOCX-Dateien erlauben
        if (!filename.endsWith('.docx')) {
            return res.status(400).send('Nur DOCX-Dateien sind erlaubt');
        }
        
        fs.writeFileSync(filePath, req.body);
        console.log(`📄 Template hochgeladen: ${filename}`);
        
        res.status(201).send('Template erfolgreich hochgeladen');
    } catch (error) {
        console.error('Template-Upload Fehler:', error);
        res.status(500).send('Fehler beim Hochladen des Templates');
    }
});

// WebDAV PUT Support für Output-Dateien (falls bearbeitet)
app.put('/webdav/output/:filename', express.raw({limit: '50mb', type: '*/*'}), (req, res) => {
    try {
        const filename = req.params.filename;
        const filePath = path.join(outputDir, filename);
        
        fs.writeFileSync(filePath, req.body);
        console.log(`📄 Output-Datei aktualisiert: ${filename}`);
        
        res.status(200).send('Datei erfolgreich aktualisiert');
    } catch (error) {
        console.error('Datei-Update Fehler:', error);
        res.status(500).send('Fehler beim Aktualisieren der Datei');
    }
});

// WebDAV DELETE Support für Templates
app.delete('/webdav/templates/:filename', (req, res) => {
    try {
        const filename = req.params.filename;
        const filePath = path.join(templatesDir, filename);
        
        if (!fs.existsSync(filePath)) {
            return res.status(404).send('Template nicht gefunden');
        }
        
        fs.unlinkSync(filePath);
        console.log(`🗑️ Template gelöscht: ${filename}`);
        
        res.status(204).send();
    } catch (error) {
        console.error('Template-Lösch Fehler:', error);
        res.status(500).send('Fehler beim Löschen des Templates');
    }
});

// WebDAV DELETE Support für Output-Dateien
app.delete('/webdav/output/:filename', (req, res) => {
    try {
        const filename = req.params.filename;
        const filePath = path.join(outputDir, filename);
        
        if (!fs.existsSync(filePath)) {
            return res.status(404).send('Datei nicht gefunden');
        }
        
        fs.unlinkSync(filePath);
        console.log(`🗑️ Output-Datei gelöscht: ${filename}`);
        
        res.status(204).send();
    } catch (error) {
        console.error('Datei-Lösch Fehler:', error);
        res.status(500).send('Fehler beim Löschen der Datei');
    }
});

// WebDAV PROPFIND für Templates-Listing
app.use('/webdav/templates', (req, res, next) => {
    if (req.method === 'PROPFIND') {
        try {
            const files = fs.readdirSync(templatesDir);
            const xmlResponse = `<?xml version="1.0" encoding="utf-8"?>
<D:multistatus xmlns:D="DAV:">
${files.map(file => {
    const filePath = path.join(templatesDir, file);
    const stats = fs.statSync(filePath);
    return `
    <D:response>
        <D:href>/webdav/templates/${file}</D:href>
        <D:propstat>
            <D:prop>
                <D:displayname>${file}</D:displayname>
                <D:getcontentlength>${stats.size}</D:getcontentlength>
                <D:getlastmodified>${stats.mtime.toUTCString()}</D:getlastmodified>
                <D:resourcetype/>
                <D:getcontenttype>application/vnd.openxmlformats-officedocument.wordprocessingml.document</D:getcontenttype>
            </D:prop>
            <D:status>HTTP/1.1 200 OK</D:status>
        </D:propstat>
    </D:response>`;
}).join('')}
</D:multistatus>`;
            
            res.set('Content-Type', 'application/xml; charset=utf-8');
            res.status(207).send(xmlResponse);
        } catch (error) {
            res.status(500).send('Server Error');
        }
    } else {
        next();
    }
});
app.use('/webdav/output', (req, res, next) => {
    if (req.method === 'PROPFIND') {
        try {
            const files = fs.readdirSync(outputDir);
            const xmlResponse = `<?xml version="1.0" encoding="utf-8"?>
<D:multistatus xmlns:D="DAV:">
${files.map(file => {
    const filePath = path.join(outputDir, file);
    const stats = fs.statSync(filePath);
    return `
    <D:response>
        <D:href>/webdav/output/${file}</D:href>
        <D:propstat>
            <D:prop>
                <D:displayname>${file}</D:displayname>
                <D:getcontentlength>${stats.size}</D:getcontentlength>
                <D:getlastmodified>${stats.mtime.toUTCString()}</D:getlastmodified>
                <D:resourcetype/>
            </D:prop>
            <D:status>HTTP/1.1 200 OK</D:status>
        </D:propstat>
    </D:response>`;
}).join('')}
</D:multistatus>`;
            
            res.set('Content-Type', 'application/xml; charset=utf-8');
            res.status(207).send(xmlResponse);
        } catch (error) {
            res.status(500).send('Server Error');
        }
    } else {
        next();
    }
});

// Route: DOCX mit Daten befüllen
app.post('/generate-document', async (req, res) => {
    try {
        const { templateName, data } = req.body;
        
        if (!templateName || !data) {
            return res.status(400).json({ 
                error: 'Template-Name und Daten sind erforderlich' 
            });
        }

        const templatePath = path.join(templatesDir, templateName);
        
        if (!fs.existsSync(templatePath)) {
            return res.status(404).json({ 
                error: 'Template nicht gefunden' 
            });
        }

        // Template laden
        const template = fs.readFileSync(templatePath);

        // Dokument mit Daten befüllen
        const buffer = await createReport({
            template,
            data: data,
            cmdDelimiter: ['++', '++'], // Andere Syntax verwenden
        });

        // Eindeutigen Dateinamen erstellen
        const timestamp = Date.now();
        const outputFileName = `document_${timestamp}.docx`;
        const outputPath = path.join(outputDir, outputFileName);

        // Befülltes Dokument speichern
        fs.writeFileSync(outputPath, buffer);

        // Download-Link zurückgeben
        res.json({
            success: true,
            downloadUrl: `/download/${outputFileName}`,
            webdavUrl: `/webdav/output/${outputFileName}`,
            msWordUrl: `ms-word:ofe|u|${getBaseUrl(req)}/webdav/output/${outputFileName}`,
            message: 'Dokument erfolgreich erstellt'
        });

    } catch (error) {
        console.error('Fehler beim Erstellen des Dokuments:', error);
        res.status(500).json({ 
            error: 'Fehler beim Erstellen des Dokuments',
            details: error.message 
        });
    }
});

// Route: Dokument herunterladen
app.get('/download/:filename', (req, res) => {
    const filename = req.params.filename;
    const filePath = path.join(outputDir, filename);

    if (!fs.existsSync(filePath)) {
        return res.status(404).json({ error: 'Datei nicht gefunden' });
    }

    res.download(filePath, filename, (err) => {
        if (err) {
            console.error('Download-Fehler:', err);
            res.status(500).json({ error: 'Download-Fehler' });
        }
    });
});

// Route: Verfügbare Templates auflisten (erweitert)
app.get('/templates', (req, res) => {
    try {
        const templates = fs.readdirSync(templatesDir)
            .filter(file => file.endsWith('.docx'))
            .map(file => {
                const filePath = path.join(templatesDir, file);
                const stats = fs.statSync(filePath);
                return {
                    name: file,
                    size: stats.size,
                    created: stats.birthtime,
                    modified: stats.mtime,
                    path: `/templates/${file}`,
                    webdavUrl: `/webdav/templates/${file}`,
                    msWordUrl: `ms-word:ofe|u|${req.secure ? 'https' : 'http'}://localhost:${req.secure ? HTTPS_PORT : PORT}/webdav/templates/${file}`
                };
            });

        res.json({
            templates,
            count: templates.length,
            webdavAccess: `/webdav/templates/`,
            uploadInfo: {
                method: 'PUT',
                url: `/webdav/templates/dateiname.docx`,
                contentType: 'application/vnd.openxmlformats-officedocument.wordprocessingml.document'
            }
        });
    } catch (error) {
        res.status(500).json({ 
            error: 'Fehler beim Auflisten der Templates' 
        });
    }
});

// Template-Management Endpoints
app.delete('/templates/:filename', (req, res) => {
    try {
        const filename = req.params.filename;
        const filePath = path.join(templatesDir, filename);
        
        if (!fs.existsSync(filePath)) {
            return res.status(404).json({ error: 'Template nicht gefunden' });
        }
        
        fs.unlinkSync(filePath);
        res.json({ 
            success: true, 
            message: `Template ${filename} gelöscht` 
        });
    } catch (error) {
        res.status(500).json({ 
            error: 'Fehler beim Löschen des Templates' 
        });
    }
});

// Template-Info Endpoint
app.get('/templates/:filename/info', (req, res) => {
    try {
        const filename = req.params.filename;
        const filePath = path.join(templatesDir, filename);
        
        if (!fs.existsSync(filePath)) {
            return res.status(404).json({ error: 'Template nicht gefunden' });
        }
        
        const stats = fs.statSync(filePath);
        res.json({
            name: filename,
            size: stats.size,
            created: stats.birthtime,
            modified: stats.mtime,
            webdavUrl: `/webdav/templates/${filename}`,
            msWordUrl: `ms-word:ofe|u|http://localhost:${PORT}/webdav/templates/${filename}`,
            downloadUrl: `/webdav/templates/${filename}`
        });
    } catch (error) {
        res.status(500).json({ 
            error: 'Fehler beim Abrufen der Template-Informationen' 
        });
    }
});

// Beispiel-Route: Daten von externem Service abrufen
app.get('/external-data/:id', async (req, res) => {
    try {
        const id = req.params.id;
        
        // Beispiel-Daten für Demonstration
        const exampleData = {
            id: id,
            name: 'Max Mustermann',
            email: 'max@beispiel.de',
            date: new Date().toLocaleDateString('de-DE'),
            items: [
                { product: 'Produkt A', quantity: 2, price: 29.99 },
                { product: 'Produkt B', quantity: 1, price: 49.99 },
                { product: 'Produkt C', quantity: 3, price: 19.99 }
            ],
            total: 129.95
        };

        res.json(exampleData);
    } catch (error) {
        res.status(500).json({ 
            error: 'Fehler beim Abrufen der externen Daten' 
        });
    }
});

// Kombinierte Route: Externe Daten abrufen und Dokument erstellen
app.post('/generate-from-external/:id', async (req, res) => {
    try {
        const id = req.params.id;
        const { templateName } = req.body;

        // Externe Daten abrufen (simulation)
        const externalData = {
            id: id,
            name: 'Max Mustermann',
            email: 'max@beispiel.de',
            date: new Date().toLocaleDateString('de-DE'),
            items: [
                { product: 'Produkt A', quantity: 2, price: 29.99 },
                { product: 'Produkt B', quantity: 1, price: 49.99 },
                { product: 'Produkt C', quantity: 3, price: 19.99 }
            ],
            total: 129.95
        };

        // Template-Pfad
        const templatePath = path.join(templatesDir, templateName);
        
        if (!fs.existsSync(templatePath)) {
            return res.status(404).json({ 
                error: 'Template nicht gefunden' 
            });
        }

        // Template laden und befüllen
        const template = fs.readFileSync(templatePath);
        const buffer = await createReport({
            template,
            data: externalData,
            cmdDelimiter: ['++', '++'],
        });

        // Datei speichern
        const timestamp = Date.now();
        const outputFileName = `document_${id}_${timestamp}.docx`;
        const outputPath = path.join(outputDir, outputFileName);
        fs.writeFileSync(outputPath, buffer);

        res.json({
            success: true,
            downloadUrl: `/download/${outputFileName}`,
            webdavUrl: `/webdav/output/${outputFileName}`,
            msWordUrl: `ms-word:ofe|u|${getBaseUrl(req)}/webdav/output/${outputFileName}`,
            data: externalData,
            message: 'Dokument mit externen Daten erstellt'
        });

    } catch (error) {
        console.error('Fehler:', error);
        res.status(500).json({ 
            error: 'Fehler beim Erstellen des Dokuments mit externen Daten' 
        });
    }
});

// Health Check
app.get('/health', (req, res) => {
    const networkIPs = getNetworkInterfaces();
    res.json({ 
        status: 'OK', 
        message: 'DOCX Template Server läuft',
        webdav: 'WebDAV-ähnliche Datei-Routen verfügbar',
        ssl: req.secure ? 'HTTPS aktiv' : 'HTTP (unverschlüsselt)',
        access: {
            local: req.secure ? `https://localhost:${HTTPS_PORT}` : `http://localhost:${PORT}`,
            network: networkIPs.map(ip => req.secure ? `https://${ip}:${HTTPS_PORT}` : `http://${ip}:${PORT}`)
        },
        timestamp: new Date().toISOString()
    });
});

// WebDAV Info Endpoint
app.get('/webdav-info', (req, res) => {
    const baseUrl = req.query.baseUrl || getBaseUrl(req);
    const networkIPs = getNetworkInterfaces();
    const protocol = req.secure ? 'https' : 'http';
    const port = req.secure ? HTTPS_PORT : PORT;
    
    res.json({
        webdav: {
            status: 'Verfügbar (ohne Authentifizierung)',
            baseUrl: baseUrl,
            ssl: req.secure ? 'HTTPS aktiv' : 'HTTP (unverschlüsselt)',
            endpoints: {
                templates: `${baseUrl}/webdav/templates/`,
                output: `${baseUrl}/webdav/output/`
            },
            alternativeURLs: {
                localhost: {
                    templates: `${protocol}://localhost:${port}/webdav/templates/`,
                    output: `${protocol}://localhost:${port}/webdav/output/`
                },
                network: networkIPs.reduce((acc, ip) => {
                    acc[ip] = {
                        templates: `${protocol}://${ip}:${port}/webdav/templates/`,
                        output: `${protocol}://${ip}:${port}/webdav/output/`
                    };
                    return acc;
                }, {})
            },
            msWordFormat: {
                templates: `ms-word:ofe|u|${baseUrl}/webdav/templates/dateiname.docx`,
                output: `ms-word:ofe|u|${baseUrl}/webdav/output/dateiname.docx`
            },
            credentials: 'Keine Authentifizierung erforderlich',
            instructions: {
                access: 'Direkte HTTP/HTTPS-Zugriffe oder MS Word Links',
                msWord: 'Verwenden Sie ms-word:ofe|u|URL Format für direktes Öffnen in Word',
                ssl: req.secure ? 'Sichere HTTPS-Verbindung aktiv' : 'Für Netzwerkzugriff HTTPS empfohlen',
                example: `ms-word:ofe|u|${baseUrl}/webdav/output/beispiel.docx`,
                networkAccess: `Server erreichbar über: localhost, ${networkIPs.join(', ')}`
            }
        }
    });
});

// Datei-Management Endpoints
app.get('/files/output', (req, res) => {
    try {
        const files = fs.readdirSync(outputDir)
            .filter(file => file.endsWith('.docx'))
            .map(file => {
                const filePath = path.join(outputDir, file);
                const stats = fs.statSync(filePath);
                return {
                    name: file,
                    size: stats.size,
                    created: stats.birthtime,
                    modified: stats.mtime,
                    webdavUrl: `/webdav/output/${file}`,
                    msWordUrl: `ms-word:ofe|u|${req.secure ? 'https' : 'http'}://localhost:${req.secure ? HTTPS_PORT : PORT}/webdav/output/${file}`,
                    downloadUrl: `/download/${file}`
                };
            })
            .sort((a, b) => b.modified - a.modified);

        res.json({
            files,
            count: files.length,
            webdavAccess: `/webdav/output/`
        });
    } catch (error) {
        res.status(500).json({ 
            error: 'Fehler beim Auflisten der Dateien' 
        });
    }
});

app.delete('/files/output/:filename', (req, res) => {
    try {
        const filename = req.params.filename;
        const filePath = path.join(outputDir, filename);
        
        if (!fs.existsSync(filePath)) {
            return res.status(404).json({ error: 'Datei nicht gefunden' });
        }
        
        fs.unlinkSync(filePath);
        res.json({ 
            success: true, 
            message: `Datei ${filename} gelöscht` 
        });
    } catch (error) {
        res.status(500).json({ 
            error: 'Fehler beim Löschen der Datei' 
        });
    }
});

// Server starten
function startServer() {
    const networkIPs = getNetworkInterfaces();
    
    // HTTP Server starten
    const httpServer = app.listen(PORT, '0.0.0.0', () => {
        console.log(`🚀 DOCX Template Server (HTTP) läuft auf Port ${PORT}`);
        console.log(`📁 Templates-Ordner: ${templatesDir}`);
        console.log(`📄 Output-Ordner: ${outputDir}`);
        console.log(`🌐 Zugriff über:`);
        console.log(`   http://localhost:${PORT}`);
        networkIPs.forEach(ip => {
            console.log(`   http://${ip}:${PORT}`);
        });
        console.log(`📂 WebDAV URLs (HTTP):`);
        console.log(`   Templates: http://localhost:${PORT}/webdav/templates/`);
        console.log(`   Output:    http://localhost:${PORT}/webdav/output/`);
    });

    // HTTPS Server starten (falls SSL-Zertifikate vorhanden)
    if (sslOptions) {
        const httpsServer = https.createServer(sslOptions, app);
        httpsServer.listen(HTTPS_PORT, '0.0.0.0', () => {
            console.log(`🔒 DOCX Template Server (HTTPS) läuft auf Port ${HTTPS_PORT}`);
            console.log(`🌐 Sichere Zugriff über:`);
            console.log(`   https://localhost:${HTTPS_PORT}`);
            networkIPs.forEach(ip => {
                console.log(`   https://${ip}:${HTTPS_PORT}`);
            });
            console.log(`📂 WebDAV URLs (HTTPS):`);
            console.log(`   Templates: https://localhost:${HTTPS_PORT}/webdav/templates/`);
            console.log(`   Output:    https://localhost:${HTTPS_PORT}/webdav/output/`);
            console.log(`🔐 SSL-verschlüsselte Verbindung aktiv`);
        });
        
        return { http: httpServer, https: httpsServer };
    } else {
        console.log(`⚠️  Nur HTTP verfügbar - für SSL Zertifikate in ssl/ Ordner bereitstellen`);
        console.log(`💡 Verwende './start.sh ssl-gen' um SSL-Zertifikate zu erstellen`);
        return { http: httpServer };
    }
}

const servers = startServer();

module.exports = app;