/**
 *  Secure Build Script - Fort-Knox Level Security
 * 
 * สคริปต์สร้างแอปแบบปลอดภัยสูงสุด รวม:
 * 1. Code Obfuscation - ทำให้โค้ดอ่านยาก
 * 2. Integrity Verification - ตรวจสอบความครบถ้วน
 * 3. Digital Signature - ลงลายเซ็นดิจิทัล
 * 4. Anti-Tampering Protection - ป้องกันการแก้ไข
 */

const fs = require('fs');
const path = require('path');
const { exec, spawn } = require('child_process');
const crypto = require('crypto');
const JavaScriptObfuscator = require('javascript-obfuscator');

// โหลด configuration
const obfuscatorConfig = require('../config/obfuscator.config.js');

class SecureBuildSystem {
    constructor() {
        this.projectRoot = path.resolve(__dirname, '..');
        this.buildDir = path.join(this.projectRoot, 'dist');
        this.tempDir = path.join(this.projectRoot, 'temp_secure_build');
        this.backupDir = path.join(this.projectRoot, 'backup_original');
        
        // ไฟล์ที่ต้อง obfuscate
        this.filesToObfuscate = [
            'main.js',
            'validation_gateway.js',
            'debug-manager.js',
            'preload.js',
            'debugger.js',
            'modules*.js',
            'backend*.js'
        ];
        
        // ไฟล์ที่ไม่ควร obfuscate
        this.excludeFromObfuscation = [
            'node_modules/**',
            'test/**',
            'tests/**',
            'spec/**',
            '**/*.test.js',
            '**/*.spec.js',
            'vendor/**',
            'build_assets/**',
            'plugins/**', // ปลั๊กอินอาจมีปัญหาถ้าโดน obfuscate
            'generate-*.js'
        ];

        console.log(' Secure Build System initialized');
    }

    /**
     * เริ่มขั้นตอนการ build แบบปลอดภัย
     */
    async startSecureBuild() {
        try {
            console.log(' Starting Fort-Knox Level Secure Build Process...');
            console.log('='.repeat(60));
            
            // 1. เตรียมการ
            await this.prepareBuildEnvironment();
            
            // 2. สำรองไฟล์ต้นฉบับ
            await this.backupOriginalFiles();
            
            // 3. Obfuscate code
            await this.obfuscateCode();
            
            // 4. Generate checksums และ signature
            await this.generateSecurityFiles();
            
            // 5. Copy user guides and documentation
            await this.copyUserDocumentation();
            
            // 6. Build Electron app
            await this.buildElectronApp();
            
            // 7. Post-build security verification
            await this.verifyBuildSecurity();
            
            // 7. Restore original files
            await this.restoreOriginalFiles();
            
            console.log(' Fort-Knox Level Secure Build completed successfully!');
            this.printBuildSummary();
            
        } catch (error) {
            console.error(' Secure Build failed:', error.message);
            
            // Restore files ในกรณีที่ build ล้มเหลว
            try {
                await this.restoreOriginalFiles();
            } catch (restoreError) {
                console.error(' Failed to restore original files:', restoreError.message);
            }
            
            process.exit(1);
        }
    }

    /**
     * เตรียมสภาพแวดล้อมสำหรับ build
     */
    async prepareBuildEnvironment() {
        console.log(' Preparing build environment...');
        
        // สร้างโฟลเดอร์ temp และ backup
        if (fs.existsSync(this.tempDir)) {
            fs.rmSync(this.tempDir, { recursive: true, force: true });
        }
        fs.mkdirSync(this.tempDir, { recursive: true });
        
        if (fs.existsSync(this.backupDir)) {
            fs.rmSync(this.backupDir, { recursive: true, force: true });
        }
        fs.mkdirSync(this.backupDir, { recursive: true });
        
        // ตรวจสอบ dependencies
        await this.checkDependencies();
        
        console.log(' Build environment prepared');
    }

    /**
     * ตรวจสอบ dependencies ที่จำเป็น
     */
    async checkDependencies() {
        const requiredPackages = [
            'javascript-obfuscator',
            'electron-builder'
        ];
        
        for (const pkg of requiredPackages) {
            try {
                require.resolve(pkg);
                console.log(` ${pkg} found`);
            } catch (error) {
                throw new Error(`Missing required package: ${pkg}. Run: npm install ${pkg}`);
            }
        }
    }

    /**
     * สำรองไฟล์ต้นฉบับ
     */
    async backupOriginalFiles() {
        console.log(' Backing up original files...');
        
        for (const filePattern of this.filesToObfuscate) {
            const files = await this.globFiles(filePattern);
            
            for (const file of files) {
                if (fs.existsSync(file)) {
                    const relativePath = path.relative(this.projectRoot, file);
                    const backupPath = path.join(this.backupDir, relativePath);
                    
                    // สร้างโฟลเดอร์ถ้าไม่มี
                    fs.mkdirSync(path.dirname(backupPath), { recursive: true });
                    
                    // Copy file
                    fs.copyFileSync(file, backupPath);
                    console.log(` Backed up: ${relativePath}`);
                }
            }
        }
        
        console.log(' Original files backed up');
    }

    /**
     * Obfuscate โค้ด JavaScript
     */
    async obfuscateCode() {
        console.log(' Starting code obfuscation...');
        
        let obfuscatedCount = 0;
        
        for (const filePattern of this.filesToObfuscate) {
            const files = await this.globFiles(filePattern);
            
            for (const file of files) {
                if (fs.existsSync(file) && !this.shouldExcludeFromObfuscation(file)) {
                    try {
                        await this.obfuscateFile(file);
                        obfuscatedCount++;
                    } catch (error) {
                        console.warn(` Failed to obfuscate ${file}: ${error.message}`);
                    }
                }
            }
        }
        
        console.log(` Code obfuscation completed (${obfuscatedCount} files processed)`);
    }

    /**
     * Obfuscate ไฟล์เดียว
     */
    async obfuscateFile(filePath) {
        const relativePath = path.relative(this.projectRoot, filePath);
        console.log(` Obfuscating: ${relativePath}`);
        
        // อ่านไฟล์ต้นฉบับ
        const originalCode = fs.readFileSync(filePath, 'utf8');
        
        // Obfuscate ด้วย configuration ที่กำหนด
        const obfuscationResult = JavaScriptObfuscator.obfuscate(originalCode, {
            ...obfuscatorConfig,
            sourceMap: false, // ไม่ต้องการ source map ใน production
            inputFileName: path.basename(filePath)
            // ลบ sourceMapFileName ออกเพราะทำให้เกิด error
        });
        
        // เขียนไฟล์ที่ obfuscate แล้วทับของเดิม
        fs.writeFileSync(filePath, obfuscationResult.getObfuscatedCode());
        
        // แสดงสถิติ
        const originalSize = Buffer.byteLength(originalCode, 'utf8');
        const obfuscatedSize = Buffer.byteLength(obfuscationResult.getObfuscatedCode(), 'utf8');
        const sizeIncrease = ((obfuscatedSize - originalSize) / originalSize * 100).toFixed(1);
        
        console.log(`   Size: ${originalSize}  ${obfuscatedSize} bytes (+${sizeIncrease}%)`);
    }

    /**
     * ตรวจสอบว่าไฟล์ควรถูกยกเว้นจาก obfuscation หรือไม่
     */
    shouldExcludeFromObfuscation(filePath) {
        const relativePath = path.relative(this.projectRoot, filePath).replace(/\\/g, '/');
        
        for (const excludePattern of this.excludeFromObfuscation) {
            if (this.matchPattern(relativePath, excludePattern)) {
                return true;
            }
        }
        
        return false;
    }

    /**
     * สร้างไฟล์ความปลอดภัย (checksums และ signature)
     */
    async generateSecurityFiles() {
        console.log(' Generating security files...');
        
        // รัน generate-checksums.js
        await this.runCommand('node generate-checksums.js');
        
        console.log(' Security files generated');
    }

    /**
     * Build Electron app
     */
    async buildElectronApp() {
        console.log(' Building Electron application...');
        
        // รันคำสั่ง electron-builder
        await this.runCommand('npm run build-msi');
        
        console.log(' Electron app built successfully');
    }

    /**
     * ตรวจสอบความปลอดภัยหลัง build
     */
    async verifyBuildSecurity() {
        console.log(' Verifying build security...');
        
        // ตรวจสอบว่าไฟล์ที่สำคัญถูก obfuscate แล้ว
        const mainJsPath = path.join(this.projectRoot, 'main.js');
        if (fs.existsSync(mainJsPath)) {
            const content = fs.readFileSync(mainJsPath, 'utf8');
            
            // ตรวจสอบว่าโค้ดถูก obfuscate แล้ว (มี pattern ของ obfuscated code)
            const hasObfuscatedPattern = (
                content.includes('_0x') || // Hexadecimal identifiers
                content.includes('var _') || // Obfuscated variables
                content.length < 1000 || // Code เป็น one-liner
                !/function\s+\w+/.test(content) // ไม่มี readable function names
            );
            
            if (hasObfuscatedPattern) {
                console.log(' Code obfuscation verified');
            } else {
                console.warn(' Code may not be properly obfuscated');
            }
        }
        
        // ตรวจสอบว่ามีไฟล์ checksums
        const checksumsPath = path.join(this.projectRoot, 'checksums.json');
        const signaturePath = path.join(this.projectRoot, 'checksums.sig');
        
        if (fs.existsSync(checksumsPath) && fs.existsSync(signaturePath)) {
            console.log(' Integrity verification files present');
        } else {
            throw new Error('Missing integrity verification files');
        }
        
        console.log(' Build security verification completed');
    }

    /**
     * กู้คืนไฟล์ต้นฉบับ
     */
    async restoreOriginalFiles() {
        console.log(' Restoring original files...');
        
        if (!fs.existsSync(this.backupDir)) {
            console.log('ℹ No backup directory found, skipping restore');
            return;
        }
        
        // Copy ไฟล์จาก backup กลับมา
        await this.copyDirectory(this.backupDir, this.projectRoot);
        
        // ลบโฟลเดอร์ backup และ temp
        fs.rmSync(this.backupDir, { recursive: true, force: true });
        fs.rmSync(this.tempDir, { recursive: true, force: true });
        
        console.log(' Original files restored');
    }

    /**
     * แสดงสรุปผลการ build
     */
    printBuildSummary() {
        console.log('\n' + '='.repeat(60));
        console.log(' FORT-KNOX LEVEL SECURE BUILD COMPLETED');
        console.log('='.repeat(60));
        console.log(' Security Features Applied:');
        console.log('   Code Obfuscation (Maximum Level)');
        console.log('   Anti-Debugging Protection');
        console.log('   IPC Command Sanitization');
        console.log('   Digital Signature Verification');
        console.log('   File Integrity Checking');
        console.log('');
        console.log(' Build Output:');
        console.log(`   ${this.buildDir}`);
        console.log('');
        console.log('  IMPORTANT:');
        console.log('  - Keep private_key.pem safe and secure');
        console.log('  - Test the built app thoroughly');
        console.log('  - The obfuscated version may run 5-15% slower');
        console.log('  - Anti-debugging will trigger in production mode');
        console.log('='.repeat(60));
    }

    // ===== HELPER METHODS =====

    async runCommand(command) {
        return new Promise((resolve, reject) => {
            console.log(` Running: ${command}`);
            exec(command, { cwd: this.projectRoot }, (error, stdout, stderr) => {
                if (error) {
                    console.error(` Command failed: ${error.message}`);
                    reject(error);
                } else {
                    if (stdout) console.log(stdout);
                    if (stderr) console.warn(stderr);
                    resolve({ stdout, stderr });
                }
            });
        });
    }

    async globFiles(pattern) {
        // Simple glob implementation
        const basePath = this.projectRoot;
        
        if (pattern.includes('**')) {
            // Recursive pattern
            const prefix = pattern.split('**')[0];
            const suffix = pattern.split('**')[1].replace('/', '');
            return this.findFilesRecursive(path.join(basePath, prefix), suffix);
        } else {
            // Direct file
            const filePath = path.join(basePath, pattern);
            return fs.existsSync(filePath) ? [filePath] : [];
        }
    }

    findFilesRecursive(dir, suffix) {
        const results = [];
        
        if (!fs.existsSync(dir)) return results;
        
        const items = fs.readdirSync(dir, { withFileTypes: true });
        
        for (const item of items) {
            const fullPath = path.join(dir, item.name);
            
            if (item.isDirectory()) {
                results.push(...this.findFilesRecursive(fullPath, suffix));
            } else if (item.name.endsWith(suffix)) {
                results.push(fullPath);
            }
        }
        
        return results;
    }

    matchPattern(path, pattern) {
        // Simple pattern matching
        const regexPattern = pattern
            .replace(/\*\*/g, '.*')
            .replace(/\*/g, '[^/]*')
            .replace(/\./g, '\\.');
        
        return new RegExp(`^${regexPattern}$`).test(path);
    }

    async copyDirectory(src, dest) {
        const items = fs.readdirSync(src, { withFileTypes: true });
        
        for (const item of items) {
            const srcPath = path.join(src, item.name);
            const destPath = path.join(dest, item.name);
            
            if (item.isDirectory()) {
                fs.mkdirSync(destPath, { recursive: true });
                await this.copyDirectory(srcPath, destPath);
            } else {
                fs.mkdirSync(path.dirname(destPath), { recursive: true });
                fs.copyFileSync(srcPath, destPath);
            }
        }
    }
    
    /**
     *  คัดลอกไฟล์คู่มือและเอกสารผู้ใช้
     */
    async copyUserDocumentation() {
        console.log(' Copying user documentation...');
        
        const documentationFiles = [
            {
                src: path.join(this.projectRoot, 'build_assets', 'plugins', 'USER_GUIDE_EN.md'),
                dest: path.join(this.projectRoot, 'USER_GUIDE_EN.md')
            },
            {
                src: path.join(this.projectRoot, 'build_assets', 'plugins', 'USER_GUIDE_TH.md'),
                dest: path.join(this.projectRoot, 'USER_GUIDE_TH.md')
            }
        ];
        
        let copiedCount = 0;
        
        for (const { src, dest } of documentationFiles) {
            try {
                if (fs.existsSync(src)) {
                    // สร้างโฟลเดอร์ปลายทางถ้ายังไม่มี
                    fs.mkdirSync(path.dirname(dest), { recursive: true });
                    
                    // คัดลอกไฟล์
                    fs.copyFileSync(src, dest);
                    console.log(`   Copied: ${path.basename(src)}  ${path.relative(this.projectRoot, dest)}`);
                    copiedCount++;
                } else {
                    console.log(`    Source not found: ${path.relative(this.projectRoot, src)}`);
                }
            } catch (error) {
                console.error(`   Failed to copy ${path.basename(src)}: ${error.message}`);
            }
        }
        
        if (copiedCount > 0) {
            console.log(` Documentation copied successfully (${copiedCount} files)`);
        } else {
            console.log('  No documentation files were copied');
        }
    }
}

// รันสคริปต์ถ้าถูกเรียกใช้โดยตรง
if (require.main === module) {
    const buildSystem = new SecureBuildSystem();
    buildSystem.startSecureBuild().catch(console.error);
}

module.exports = SecureBuildSystem;