// CVE Management Backend API
// Install: npm install express sqlite3 multer cors dotenv bcryptjs cookie-parser

require('dotenv').config();

const express = require('express');
const sqlite3 = require('sqlite3').verbose();
const multer = require('multer');
const cors = require('cors');
const cookieParser = require('cookie-parser');
const path = require('path');
const fs = require('fs');

// Auth imports
const { requireAuth, requireRole } = require('./middleware/auth');
const createAuthRouter = require('./routes/auth');
const createUsersRouter = require('./routes/users');
const createAuditLogRouter = require('./routes/auditLog');
const logAudit = require('./helpers/auditLog');
const createNvdLookupRouter = require('./routes/nvdLookup');

const app = express();
const PORT = process.env.PORT || 3001;
const API_HOST = process.env.API_HOST || 'localhost';
const SESSION_SECRET = process.env.SESSION_SECRET || 'default-secret-change-me';
const CORS_ORIGINS = process.env.CORS_ORIGINS
    ? process.env.CORS_ORIGINS.split(',')
    : ['http://localhost:3000'];

// Log all incoming requests
app.use((req, res, next) => {
    console.log(`${new Date().toISOString()} - ${req.method} ${req.url}`);
    next();
});

// Middleware
app.use(cors({
  origin: CORS_ORIGINS,
  credentials: true
}));
app.use(express.json());
app.use(cookieParser());
app.use('/uploads', express.static('uploads'));

// Database connection
const db = new sqlite3.Database('./cve_database.db', (err) => {
    if (err) console.error('Database connection error:', err);
    else console.log('Connected to CVE database');
});

// Auth routes (public)
app.use('/api/auth', createAuthRouter(db, logAudit));

// User management routes (admin only)
app.use('/api/users', createUsersRouter(db, requireAuth, requireRole, logAudit));

// Audit log routes (admin only)
app.use('/api/audit-logs', createAuditLogRouter(db, requireAuth, requireRole));

// NVD lookup routes (authenticated users)
app.use('/api/nvd', createNvdLookupRouter(db, requireAuth));

// Simple storage - upload to temp directory first
const storage = multer.diskStorage({
    destination: (req, file, cb) => {
        const tempDir = 'uploads/temp';
        if (!fs.existsSync(tempDir)) {
            fs.mkdirSync(tempDir, { recursive: true });
        }
        cb(null, tempDir);
    },
    filename: (req, file, cb) => {
        const timestamp = Date.now();
        cb(null, `${timestamp}-${file.originalname}`);
    }
});

const upload = multer({ 
    storage: storage,
    limits: { fileSize: 10 * 1024 * 1024 } // 10MB limit
});

// ========== CVE ENDPOINTS ==========

// Get all CVEs with optional filters (authenticated users)
app.get('/api/cves', requireAuth(db), (req, res) => {
    const { search, vendor, severity, status } = req.query;
    
    let query = `
        SELECT c.*, 
               COUNT(d.id) as document_count,
               CASE 
                   WHEN COUNT(CASE WHEN d.type = 'advisory' THEN 1 END) > 0 
                   THEN 'Complete'
                   ELSE 'Incomplete'
               END as doc_status
        FROM cves c
        LEFT JOIN documents d ON c.cve_id = d.cve_id
        WHERE 1=1
    `;
    
    const params = [];
    
    if (search) {
        query += ` AND (c.cve_id LIKE ? OR c.description LIKE ?)`;
        params.push(`%${search}%`, `%${search}%`);
    }
    if (vendor && vendor !== 'All Vendors') {
        query += ` AND c.vendor = ?`;
        params.push(vendor);
    }
    if (severity && severity !== 'All Severities') {
        query += ` AND c.severity = ?`;
        params.push(severity);
    }
    if (status) {
        query += ` AND c.status = ?`;
        params.push(status);
    }
    
    query += ` GROUP BY c.id ORDER BY c.published_date DESC`;
    
    db.all(query, params, (err, rows) => {
        if (err) {
            console.error('Error fetching CVEs:', err);
            return res.status(500).json({ error: err.message });
        }
        res.json(rows);
    });
});

// Get distinct CVE IDs for NVD sync (authenticated users)
app.get('/api/cves/distinct-ids', requireAuth(db), (req, res) => {
    db.all('SELECT DISTINCT cve_id FROM cves ORDER BY cve_id', [], (err, rows) => {
        if (err) return res.status(500).json({ error: err.message });
        res.json(rows.map(r => r.cve_id));
    });
});

// Check if CVE exists and get its status - UPDATED FOR MULTI-VENDOR (authenticated users)
app.get('/api/cves/check/:cveId', requireAuth(db), (req, res) => {
    const { cveId } = req.params;
    
    const query = `
        SELECT c.*, 
               COUNT(d.id) as total_documents,
               COUNT(CASE WHEN d.type = 'advisory' THEN 1 END) as has_advisory,
               COUNT(CASE WHEN d.type = 'email' THEN 1 END) as has_email,
               COUNT(CASE WHEN d.type = 'screenshot' THEN 1 END) as has_screenshot
        FROM cves c
        LEFT JOIN documents d ON c.cve_id = d.cve_id AND c.vendor = d.vendor
        WHERE c.cve_id = ?
        GROUP BY c.id
    `;
    
    db.all(query, [cveId], (err, rows) => {
        if (err) {
            return res.status(500).json({ error: err.message });
        }
        if (!rows || rows.length === 0) {
            return res.json({ 
                exists: false, 
                message: 'CVE not found - not yet addressed' 
            });
        }
        
        // Return all vendor entries for this CVE
        res.json({
            exists: true,
            vendors: rows.map(row => ({
                vendor: row.vendor,
                severity: row.severity,
                status: row.status,
                total_documents: row.total_documents,
                compliance: {
                    advisory: row.has_advisory > 0,
                    email: row.has_email > 0,
                    screenshot: row.has_screenshot > 0
                }
            })),
            addressed: true,
            has_required_docs: rows.some(row => row.has_advisory > 0)
        });
    });
});

// NEW ENDPOINT: Get all vendors for a specific CVE (authenticated users)
app.get('/api/cves/:cveId/vendors', requireAuth(db), (req, res) => {
    const { cveId } = req.params;
    
    const query = `
        SELECT vendor, severity, status, description, published_date
        FROM cves
        WHERE cve_id = ?
        ORDER BY vendor
    `;
    
    db.all(query, [cveId], (err, rows) => {
        if (err) {
            return res.status(500).json({ error: err.message });
        }
        res.json(rows);
    });
});


// Create new CVE entry - ALLOW MULTIPLE VENDORS (editor or admin)
app.post('/api/cves', requireAuth(db), requireRole('editor', 'admin'), (req, res) => {
    console.log('=== ADD CVE REQUEST ===');
    console.log('Body:', req.body);
    console.log('=======================');
    
    const { cve_id, vendor, severity, description, published_date } = req.body;

    const query = `
        INSERT INTO cves (cve_id, vendor, severity, description, published_date)
        VALUES (?, ?, ?, ?, ?)
    `;

    console.log('Query:', query);
    console.log('Values:', [cve_id, vendor, severity, description, published_date]);

    db.run(query, [cve_id, vendor, severity, description, published_date], function(err) {
        if (err) {
            console.error('DATABASE ERROR:', err);  // Make sure this is here
            // ... rest of error handling
            // Check if it's a duplicate CVE_ID + Vendor combination
            if (err.message.includes('UNIQUE constraint failed')) {
                return res.status(409).json({ 
                    error: 'This CVE already exists for this vendor. Choose a different vendor or update the existing entry.' 
                });
            }
            return res.status(500).json({ error: err.message });
        }
        logAudit(db, {
            userId: req.user.id,
            username: req.user.username,
            action: 'cve_create',
            entityType: 'cve',
            entityId: cve_id,
            details: { vendor, severity },
            ipAddress: req.ip
        });
        res.json({
            id: this.lastID,
            cve_id,
            message: `CVE created successfully for vendor: ${vendor}`
        });
    });
});


// Update CVE status (editor or admin)
app.patch('/api/cves/:cveId/status', requireAuth(db), requireRole('editor', 'admin'), (req, res) => {
    const { cveId } = req.params;
    const { status } = req.body;
    
    const query = `UPDATE cves SET status = ?, updated_at = CURRENT_TIMESTAMP WHERE cve_id = ?`;

    db.run(query, [status, cveId], function(err) {
        if (err) {
            return res.status(500).json({ error: err.message });
        }
        logAudit(db, {
            userId: req.user.id,
            username: req.user.username,
            action: 'cve_update_status',
            entityType: 'cve',
            entityId: cveId,
            details: { status },
            ipAddress: req.ip
        });
        res.json({ message: 'Status updated successfully', changes: this.changes });
    });
});

// Bulk sync CVE data from NVD (editor or admin)
app.post('/api/cves/nvd-sync', requireAuth(db), requireRole('editor', 'admin'), (req, res) => {
    const { updates } = req.body;
    if (!Array.isArray(updates) || updates.length === 0) {
        return res.status(400).json({ error: 'No updates provided' });
    }

    let updated = 0;
    const errors = [];
    let completed = 0;

    db.serialize(() => {
        updates.forEach((entry) => {
            const fields = [];
            const values = [];
            if (entry.description !== null && entry.description !== undefined) {
                fields.push('description = ?');
                values.push(entry.description);
            }
            if (entry.severity !== null && entry.severity !== undefined) {
                fields.push('severity = ?');
                values.push(entry.severity);
            }
            if (entry.published_date !== null && entry.published_date !== undefined) {
                fields.push('published_date = ?');
                values.push(entry.published_date);
            }
            if (fields.length === 0) {
                completed++;
                if (completed === updates.length) sendResponse();
                return;
            }
            fields.push('updated_at = CURRENT_TIMESTAMP');
            values.push(entry.cve_id);

            db.run(
                `UPDATE cves SET ${fields.join(', ')} WHERE cve_id = ?`,
                values,
                function(err) {
                    if (err) {
                        errors.push({ cve_id: entry.cve_id, error: err.message });
                    } else {
                        updated += this.changes;
                    }
                    completed++;
                    if (completed === updates.length) sendResponse();
                }
            );
        });
    });

    function sendResponse() {
        logAudit(db, {
            userId: req.user.id,
            username: req.user.username,
            action: 'cve_nvd_sync',
            entityType: 'cve',
            entityId: null,
            details: { count: updated, cve_ids: updates.map(u => u.cve_id) },
            ipAddress: req.ip
        });
        const result = { message: 'NVD sync completed', updated };
        if (errors.length > 0) result.errors = errors;
        res.json(result);
    }
});

// ========== DOCUMENT ENDPOINTS ==========

// Get documents for a CVE - FILTER BY VENDOR (authenticated users)
app.get('/api/cves/:cveId/documents', requireAuth(db), (req, res) => {
    const { cveId } = req.params;
    const { vendor } = req.query;  // NEW: Optional vendor filter
    
    let query = `SELECT * FROM documents WHERE cve_id = ?`;
    let params = [cveId];
    
    if (vendor) {
        query += ` AND vendor = ?`;
        params.push(vendor);
    }
    
    query += ` ORDER BY uploaded_at DESC`;
    
    db.all(query, params, (err, rows) => {
        if (err) {
            return res.status(500).json({ error: err.message });
        }
        res.json(rows);
    });
});

// Upload document - ADD ERROR HANDLING FOR MULTER (editor or admin)
app.post('/api/cves/:cveId/documents', requireAuth(db), requireRole('editor', 'admin'), (req, res, next) => {
    upload.single('file')(req, res, (err) => {
        if (err) {
            console.error('MULTER ERROR:', err);
            return res.status(500).json({ error: 'File upload failed: ' + err.message });
        }
        
        console.log('=== UPLOAD REQUEST RECEIVED ===');
        console.log('CVE ID:', req.params.cveId);
        console.log('Body:', req.body);
        console.log('File:', req.file);
        console.log('================================');
        
        const { cveId } = req.params;
        const { type, notes, vendor } = req.body;
        const file = req.file;

        if (!file) {
            console.error('ERROR: No file uploaded');
            return res.status(400).json({ error: 'No file uploaded' });
        }

        if (!vendor) {
            console.error('ERROR: Vendor is required');
            return res.status(400).json({ error: 'Vendor is required' });
        }

        // Move file from temp to proper location
        const finalDir = path.join('uploads', cveId, vendor);
        if (!fs.existsSync(finalDir)) {
            fs.mkdirSync(finalDir, { recursive: true });
        }

        const finalPath = path.join(finalDir, file.filename);

        // Move file from temp to final location
        fs.renameSync(file.path, finalPath);

        const query = `
            INSERT INTO documents (cve_id, vendor, name, type, file_path, file_size, mime_type, notes)
            VALUES (?, ?, ?, ?, ?, ?, ?, ?)
        `;

        const fileSizeKB = (file.size / 1024).toFixed(2) + ' KB';

        db.run(query, [
            cveId,
            vendor,
            file.originalname,
            type,
            finalPath,
            fileSizeKB,
            file.mimetype,
            notes
        ], function(err) {
            if (err) {
                console.error('DATABASE ERROR:', err);
                // If database insert fails, delete the file
                if (fs.existsSync(finalPath)) {
                    fs.unlinkSync(finalPath);
                }
                return res.status(500).json({ error: err.message });
            }
            logAudit(db, {
                userId: req.user.id,
                username: req.user.username,
                action: 'document_upload',
                entityType: 'document',
                entityId: cveId,
                details: { vendor, type, filename: file.originalname },
                ipAddress: req.ip
            });
            res.json({
                id: this.lastID,
                message: 'Document uploaded successfully',
                file: {
                    name: file.originalname,
                    path: finalPath,
                    size: fileSizeKB
                }
            });
        });
    });
});
// Delete document (admin only)
app.delete('/api/documents/:id', requireAuth(db), requireRole('admin'), (req, res) => {
    const { id } = req.params;
    
    // First get the file path to delete the actual file
    db.get('SELECT file_path FROM documents WHERE id = ?', [id], (err, row) => {
        if (err) {
            return res.status(500).json({ error: err.message });
        }
        
        if (row && fs.existsSync(row.file_path)) {
            fs.unlinkSync(row.file_path);
        }
        
        db.run('DELETE FROM documents WHERE id = ?', [id], function(err) {
            if (err) {
                return res.status(500).json({ error: err.message });
            }
            logAudit(db, {
                userId: req.user.id,
                username: req.user.username,
                action: 'document_delete',
                entityType: 'document',
                entityId: id,
                details: { file_path: row ? row.file_path : null },
                ipAddress: req.ip
            });
            res.json({ message: 'Document deleted successfully' });
        });
    });
});

// ========== UTILITY ENDPOINTS ==========

// Get all vendors (authenticated users)
app.get('/api/vendors', requireAuth(db), (req, res) => {
    const query = `SELECT DISTINCT vendor FROM cves ORDER BY vendor`;
    
    db.all(query, [], (err, rows) => {
        if (err) {
            return res.status(500).json({ error: err.message });
        }
        res.json(rows.map(r => r.vendor));
    });
});

// Get statistics (authenticated users)
app.get('/api/stats', requireAuth(db), (req, res) => {
    const query = `
        SELECT 
            COUNT(DISTINCT c.id) as total_cves,
            COUNT(DISTINCT CASE WHEN c.severity = 'Critical' THEN c.id END) as critical_count,
            COUNT(DISTINCT CASE WHEN c.status = 'Addressed' THEN c.id END) as addressed_count,
            COUNT(DISTINCT d.id) as total_documents,
            COUNT(DISTINCT CASE WHEN cd.compliance_status = 'Complete' THEN c.id END) as compliant_count
        FROM cves c
        LEFT JOIN documents d ON c.cve_id = d.cve_id
        LEFT JOIN cve_document_status cd ON c.cve_id = cd.cve_id
    `;
    
    db.get(query, [], (err, row) => {
        if (err) {
            return res.status(500).json({ error: err.message });
        }
        res.json(row);
    });
});

// Start server
app.listen(PORT, () => {
    console.log(`CVE API server running on http://${API_HOST}:${PORT}`);
    console.log(`CORS origins: ${CORS_ORIGINS.join(', ')}`);
});