package main

import (
	"bytes"
	"context"
	"crypto/rand"
	"crypto/rsa"
	"crypto/tls"
	"crypto/x509"
	"crypto/x509/pkix"
	"encoding/pem"
	"flag"
	"fmt"
	"io"
	"log"
	"math/big"
	"net"
	"net/http"
	"net/url"
	"os"
	"os/exec"
	"os/signal"
	"path/filepath"
	"runtime"
	"strings"
	"syscall"
	"time"

	"golang.org/x/sys/windows/registry"
)

type Config struct {
	DomainsOfInterest []string
	Proxy             struct {
		Port int
	}
	Dump struct {
		OutputDir string
	}
}

type ProxyServer struct {
	config        *Config
	tlsConfig     *tls.Config
	server        *http.Server
	originalProxy string
}

// testMode can be set via build flags for UTF-8 testing
var testMode string

func main() {
	// Parse command line flags
	var testConnectivity = flag.Bool("test", false, "Test proxy connectivity")
	flag.Parse()

	// Set console to UTF-8 on Windows to prevent garbled text
	if runtime.GOOS == "windows" {
		setConsoleUTF8()
	}

	fmt.Println("Starting MITM proxy server...")

	// If in test mode, output UTF-8 test characters and exit
	if testMode == "true" {
		fmt.Println("========================================")
		fmt.Println("UTF-8 Encoding Test")
		fmt.Println("========================================")
		fmt.Println("Testing Unicode characters:")
		fmt.Println("English: Hello World")
		fmt.Println("Chinese: 你好世界")
		fmt.Println("Japanese: こんにちは世界")
		fmt.Println("Korean: 안녕하세요 세계")
		fmt.Println("Symbols: ✓ ✗ ★ ♥ ◆ ▲")
		fmt.Println("")
		fmt.Println("If you can see the above characters correctly,")
		fmt.Println("UTF-8 encoding is working properly in the MITM proxy.")
		fmt.Println("========================================")
		return
	}

	// Load configuration
	config, err := loadConfig("config.toml")
	if err != nil {
		log.Fatalf("Failed to load configuration: %v", err)
	}

	// Create output directory
	if err := os.MkdirAll(config.Dump.OutputDir, 0755); err != nil {
		log.Fatalf("Failed to create output directory: %v", err)
	}

	// Create proxy server
	proxy, err := NewProxyServer(config)
	if err != nil {
		log.Fatalf("Failed to create proxy server: %v", err)
	}

	// Install CA certificate
	if err := proxy.installCACert(); err != nil {
		log.Printf("Failed to install CA certificate: %v", err)
	} else {
		fmt.Println("✓ CA certificate installed successfully")
	}

	// Set system proxy
	if err := proxy.setSystemProxy(); err != nil {
		log.Fatalf("Failed to set system proxy: %v", err)
	}
	fmt.Printf("✓ System proxy set to 127.0.0.1:%d\n", config.Proxy.Port)

	// Verify proxy settings were applied
	if err := proxy.verifyProxySettings(); err != nil {
		fmt.Printf("⚠️  Warning: Could not verify proxy settings: %v\n", err)
	} else {
		fmt.Printf("✓ Proxy settings verified in Windows registry\n")
	}

	// Show current proxy configuration for debugging
	proxy.showProxyConfiguration()

	// Start proxy server
	serverStarted := make(chan error, 1)
	go func() {
		fmt.Printf("🚀 Starting proxy server on port %d...\n", config.Proxy.Port)
		if err := proxy.Start(); err != nil && err != http.ErrServerClosed {
			serverStarted <- err
			return
		}
		serverStarted <- nil
	}()

	// Wait for server to start or fail
	fmt.Printf("⏳ Waiting for server to start...\n")
	select {
	case err := <-serverStarted:
		if err != nil {
			log.Fatalf("❌ Failed to start proxy server: %v", err)
		}
		fmt.Printf("✅ Proxy server successfully started on port %d\n", config.Proxy.Port)
	case <-time.After(5 * time.Second):
		fmt.Printf("✅ Proxy server appears to be starting (no immediate errors)\n")
	}

	// Test basic connectivity first
	fmt.Printf("🔍 Testing basic proxy connectivity...\n")
	if err := testBasicConnectivity(config.Proxy.Port); err != nil {
		fmt.Printf("⚠️  Basic connectivity test failed: %v\n", err)
		fmt.Printf("💡 Try running diagnose_proxy.bat for detailed diagnostics\n")
	} else {
		fmt.Printf("✅ Basic proxy connectivity test passed\n")
	}

	// Run full connectivity test if requested
	if *testConnectivity {
		proxyAddr := fmt.Sprintf("127.0.0.1:%d", config.Proxy.Port)
		testProxyConnectivity(proxyAddr)
	}

	// Wait for interrupt signal
	sigChan := make(chan os.Signal, 1)
	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
	<-sigChan

	fmt.Println("\n🛑 Shutting down proxy server...")
	proxy.Shutdown()
	fmt.Println("✓ Proxy server closed")
}

func loadConfig(filename string) (*Config, error) {
	return parseConfig(filename)
}

func NewProxyServer(config *Config) (*ProxyServer, error) {
	// Load hardcoded P12 certificate
	tlsConfig, err := loadHardcodedCertificate()
	if err != nil {
		return nil, fmt.Errorf("failed to load certificate: %v", err)
	}

	proxy := &ProxyServer{
		config:    config,
		tlsConfig: tlsConfig,
	}

	// Create HTTP server with enhanced logging
	// IMPORTANT: Use a custom handler that properly handles CONNECT requests
	proxy.server = &http.Server{
		Addr:    fmt.Sprintf(":%d", config.Proxy.Port),
		Handler: proxy, // Use the proxy itself as the handler
		// Add some server configuration for better debugging
		ErrorLog: log.New(os.Stdout, "HTTP-SERVER: ", log.LstdFlags),
	}

	return proxy, nil
}

func (p *ProxyServer) Start() error {
	fmt.Printf("🔧 Starting HTTP server on %s\n", p.server.Addr)

	// Test if port is available
	listener, err := net.Listen("tcp", p.server.Addr)
	if err != nil {
		return fmt.Errorf("failed to bind to port %s: %v", p.server.Addr, err)
	}

	fmt.Printf("✅ Successfully bound to port %s\n", p.server.Addr)

	// Start serving with our listener
	return p.server.Serve(listener)
}

func (p *ProxyServer) Shutdown() {
	// Restore system proxy settings
	if err := p.restoreSystemProxy(); err != nil {
		log.Printf("Failed to restore system proxy: %v", err)
	} else {
		fmt.Println("✓ System proxy restored")
	}

	// Close HTTP server
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()
	p.server.Shutdown(ctx)
}

func (p *ProxyServer) createTLSConfigForHost(host string) *tls.Config {
	// Create a TLS config that generates certificates on-demand
	config := &tls.Config{
		InsecureSkipVerify: true,
		GetCertificate: func(info *tls.ClientHelloInfo) (*tls.Certificate, error) {
			// Generate a certificate specifically for this host
			return p.generateCertificateForHost(info.ServerName)
		},
	}
	return config
}

// generateCertificateForHost creates a certificate for a specific hostname
func (p *ProxyServer) generateCertificateForHost(hostname string) (*tls.Certificate, error) {
	// Use the CA certificate and key from our base config
	if len(p.tlsConfig.Certificates) == 0 {
		return nil, fmt.Errorf("no CA certificate available")
	}

	caCert := p.tlsConfig.Certificates[0]

	// Parse the CA certificate
	caCertParsed, err := x509.ParseCertificate(caCert.Certificate[0])
	if err != nil {
		return nil, fmt.Errorf("failed to parse CA certificate: %v", err)
	}

	// Generate a new private key for the host certificate
	hostPrivateKey, err := rsa.GenerateKey(rand.Reader, 2048)
	if err != nil {
		return nil, fmt.Errorf("failed to generate host private key: %v", err)
	}

	// Create certificate template for the specific host
	template := x509.Certificate{
		SerialNumber: big.NewInt(time.Now().UnixNano()),
		Subject: pkix.Name{
			Organization: []string{"MITM Proxy"},
			Country:      []string{"US"},
			CommonName:   hostname,
		},
		NotBefore: time.Now(),
		NotAfter:  time.Now().Add(365 * 24 * time.Hour),
		// Proper key usage for server certificate
		KeyUsage: x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
		ExtKeyUsage: []x509.ExtKeyUsage{
			x509.ExtKeyUsageServerAuth,
		},
		BasicConstraintsValid: true,
		IsCA:                  false,
	}

	// Add the hostname to DNS names
	template.DNSNames = []string{hostname}

	// If hostname is an IP address, add it to IP addresses
	if ip := net.ParseIP(hostname); ip != nil {
		template.IPAddresses = []net.IP{ip}
	}

	// Generate the certificate signed by our CA
	certDER, err := x509.CreateCertificate(rand.Reader, &template, caCertParsed, &hostPrivateKey.PublicKey, caCert.PrivateKey)
	if err != nil {
		return nil, fmt.Errorf("failed to create certificate for %s: %v", hostname, err)
	}

	// Create the TLS certificate
	cert := &tls.Certificate{
		Certificate: [][]byte{certDER},
		PrivateKey:  hostPrivateKey,
	}

	return cert, nil
}

// ServeHTTP implements http.Handler interface to properly handle all requests including CONNECT
func (p *ProxyServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	// Handle health check endpoint
	if r.URL.Path == "/proxy-health" {
		fmt.Printf("🏥 Health check request from %s\n", r.RemoteAddr)
		w.Header().Set("Content-Type", "text/plain")
		w.WriteHeader(http.StatusOK)
		w.Write([]byte("MITM Proxy is running"))
		return
	}

	// Handle all other requests through our main handler
	p.handleHTTP(w, r)
}

func (p *ProxyServer) handleHTTP(w http.ResponseWriter, r *http.Request) {
	// Log all incoming requests for debugging with timestamp
	timestamp := time.Now().Format("15:04:05")
	fmt.Printf("[%s] 📥 INCOMING: %s %s %s from %s\n", timestamp, r.Method, r.Host, r.URL.Path, r.RemoteAddr)
	fmt.Printf("[%s] 📋 Headers: %d headers received\n", timestamp, len(r.Header))

	// Log ALL headers for debugging proxy issues
	for name, values := range r.Header {
		for _, value := range values {
			fmt.Printf("[%s] 📋 Header: %s: %s\n", timestamp, name, value)
		}
	}

	// Log the complete URL being requested
	fmt.Printf("[%s] 🌐 Full URL: %s\n", timestamp, r.URL.String())

	// Check if this is actually an HTTPS request being sent as HTTP
	if r.URL.Scheme == "https" {
		fmt.Printf("[%s] ⚠️  HTTPS URL received as HTTP request - browser may not be using CONNECT\n", timestamp)
	}

	if r.Method == http.MethodConnect {
		fmt.Printf("[%s] 🔐 Processing HTTPS CONNECT for %s\n", timestamp, r.Host)
		p.handleHTTPS(w, r)
		return
	}

	// Handle HTTP request
	fmt.Printf("[%s] 🌐 Processing HTTP request for %s\n", timestamp, r.Host)
	p.handleHTTPRequest(w, r)
}

func (p *ProxyServer) handleHTTPS(w http.ResponseWriter, r *http.Request) {
	timestamp := time.Now().Format("15:04:05")
	fmt.Printf("[%s] 🔐 HTTPS CONNECT: Starting for %s from %s\n", timestamp, r.Host, r.RemoteAddr)

	// Get the hijacker before sending any response
	hijacker, ok := w.(http.Hijacker)
	if !ok {
		fmt.Printf("[%s] ❌ HTTPS CONNECT: Hijacking not supported for %s\n", timestamp, r.Host)
		http.Error(w, "Hijacking not supported", http.StatusInternalServerError)
		return
	}
	fmt.Printf("[%s] ✅ HTTPS CONNECT: Hijacker obtained for %s\n", timestamp, r.Host)

	// Hijack the connection first
	clientConn, _, err := hijacker.Hijack()
	if err != nil {
		fmt.Printf("[%s] ❌ HTTPS CONNECT: Hijack failed for %s: %v\n", timestamp, r.Host, err)
		http.Error(w, err.Error(), http.StatusServiceUnavailable)
		return
	}
	defer func() {
		fmt.Printf("[%s] 🔌 HTTPS CONNECT: Closing client connection for %s\n", timestamp, r.Host)
		clientConn.Close()
	}()
	fmt.Printf("[%s] ✅ HTTPS CONNECT: Connection hijacked for %s\n", timestamp, r.Host)

	// Send 200 Connection established response manually
	connectResponse := "HTTP/1.1 200 Connection established\r\n\r\n"
	written, err := clientConn.Write([]byte(connectResponse))
	if err != nil {
		fmt.Printf("[%s] ❌ HTTPS CONNECT: Failed to send response to %s: %v\n", timestamp, r.Host, err)
		return
	}
	fmt.Printf("[%s] ✅ HTTPS CONNECT: Sent %d bytes response to %s\n", timestamp, written, r.Host)

	// Give the client a moment to process the CONNECT response
	time.Sleep(100 * time.Millisecond)

	// Try MITM first - if it fails, fall back to transparent proxy
	fmt.Printf("[%s] 🔍 HTTPS CONNECT: Attempting MITM for %s\n", timestamp, r.Host)
	if !p.attemptMITM(clientConn, r.Host) {
		fmt.Printf("[%s] ⚠️  HTTPS CONNECT: MITM failed for %s, falling back to transparent proxy\n", timestamp, r.Host)
		p.handleHTTPSTransparent(clientConn, r.Host)
	}
}

// attemptMITM tries to perform MITM decryption, returns true if successful
func (p *ProxyServer) attemptMITM(clientConn net.Conn, host string) bool {
	timestamp := time.Now().Format("15:04:05")
	fmt.Printf("[%s] 🔍 MITM: Attempting MITM for %s\n", timestamp, host)

	// First establish connection to target server
	fmt.Printf("[%s] 🌐 MITM: Connecting to target %s\n", timestamp, host)
	destConn, err := tls.Dial("tcp", host, &tls.Config{
		InsecureSkipVerify: true,
	})
	if err != nil {
		fmt.Printf("[%s] ❌ MITM: Cannot connect to target %s with TLS: %v\n", timestamp, host, err)
		return false
	}
	defer destConn.Close()
	fmt.Printf("[%s] ✅ MITM: Connected to target %s\n", timestamp, host)

	// Create TLS config for client connection
	fmt.Printf("[%s] 🔧 MITM: Creating TLS config for client connection to %s\n", timestamp, host)
	tlsConfig := p.createTLSConfigForHost(host)

	// Wrap client connection with our certificate
	fmt.Printf("[%s] 🔐 MITM: Wrapping client connection with our certificate for %s\n", timestamp, host)
	tlsClientConn := tls.Server(clientConn, tlsConfig)
	defer tlsClientConn.Close()

	// Set handshake timeout
	fmt.Printf("[%s] ⏰ MITM: Setting TLS handshake timeout for %s\n", timestamp, host)
	tlsClientConn.SetDeadline(time.Now().Add(10 * time.Second))

	// Try TLS handshake with client
	fmt.Printf("[%s] 🤝 MITM: Starting TLS handshake with client for %s\n", timestamp, host)
	if err := tlsClientConn.Handshake(); err != nil {
		fmt.Printf("[%s] ❌ MITM: TLS handshake failed for %s: %v\n", timestamp, host, err)
		return false
	}

	// Clear deadline after successful handshake
	tlsClientConn.SetDeadline(time.Time{})
	fmt.Printf("[%s] ✅ MITM: TLS handshake successful for %s - decrypting traffic\n", timestamp, host)

	// Create channels for bidirectional copying
	done := make(chan struct{}, 2)

	// Copy data bidirectionally with decryption
	go func() {
		defer func() {
			fmt.Printf("[%s] 📤 MITM: Response copying finished for %s\n", timestamp, host)
			done <- struct{}{}
		}()
		p.copyAndDumpDecrypted(destConn, tlsClientConn, host, "response")
	}()

	go func() {
		defer func() {
			fmt.Printf("[%s] 📥 MITM: Request copying finished for %s\n", timestamp, host)
			done <- struct{}{}
		}()
		p.copyAndDumpDecrypted(tlsClientConn, destConn, host, "request")
	}()

	// Wait for one direction to close
	<-done
	fmt.Printf("[%s] 🔚 MITM: Connection to %s closed\n", timestamp, host)
	return true
}

// handleHTTPSTransparent handles transparent HTTPS proxy (when TLS decryption fails)
func (p *ProxyServer) handleHTTPSTransparent(clientConn net.Conn, host string) {
	timestamp := time.Now().Format("15:04:05")
	fmt.Printf("[%s] 🔄 TRANSPARENT: Starting transparent proxy for %s\n", timestamp, host)

	// Set connection timeout
	clientConn.SetDeadline(time.Now().Add(30 * time.Second))
	defer clientConn.SetDeadline(time.Time{})

	// Establish connection to target server
	fmt.Printf("[%s] 🌐 TRANSPARENT: Connecting to target %s\n", timestamp, host)
	destConn, err := net.DialTimeout("tcp", host, 10*time.Second)
	if err != nil {
		fmt.Printf("[%s] ❌ TRANSPARENT: Failed to connect to target server %s: %v\n", timestamp, host, err)
		return
	}
	defer destConn.Close()
	fmt.Printf("[%s] ✅ TRANSPARENT: Connected to target %s\n", timestamp, host)

	// Set timeout for destination connection
	destConn.SetDeadline(time.Now().Add(30 * time.Second))
	defer destConn.SetDeadline(time.Time{})

	fmt.Printf("[%s] 🔗 TRANSPARENT: Established transparent proxy connection to %s\n", timestamp, host)

	// Create channels to handle connection closing
	done := make(chan struct{}, 2)

	// Transparently proxy encrypted data
	go func() {
		defer func() {
			fmt.Printf("[%s] 📤 TRANSPARENT: Response copying finished for %s\n", timestamp, host)
			done <- struct{}{}
		}()
		p.copyAndDump(destConn, clientConn, host, "response")
	}()

	go func() {
		defer func() {
			fmt.Printf("[%s] 📥 TRANSPARENT: Request copying finished for %s\n", timestamp, host)
			done <- struct{}{}
		}()
		p.copyAndDump(clientConn, destConn, host, "request")
	}()

	// Wait for one direction to close, then close both connections
	<-done
	fmt.Printf("[%s] 🔚 TRANSPARENT: Proxy connection to %s closed\n", timestamp, host)
}

func (p *ProxyServer) handleHTTPRequest(w http.ResponseWriter, r *http.Request) {
	// Build the complete target URL
	targetURL := r.URL
	if targetURL.Scheme == "" {
		targetURL.Scheme = "http"
	}
	if targetURL.Host == "" {
		targetURL.Host = r.Host
	}

	// Read request body for dumping
	var reqBody []byte
	if r.Body != nil {
		var err error
		reqBody, err = io.ReadAll(r.Body)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
		r.Body = io.NopCloser(bytes.NewReader(reqBody))
	}

	// Create new request with exact same properties
	proxyReq, err := http.NewRequest(r.Method, targetURL.String(), bytes.NewReader(reqBody))
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Copy ALL headers exactly as-is (completely transparent)
	proxyReq.Header = make(http.Header)
	for name, values := range r.Header {
		proxyReq.Header[name] = values
	}

	// Create a completely transparent HTTP client
	client := &http.Client{
		Transport: &http.Transport{
			TLSClientConfig: &tls.Config{
				InsecureSkipVerify: true, // For MITM purposes
			},
			DisableKeepAlives:     false,
			DisableCompression:    true, // Keep original compression
			MaxIdleConns:          100,
			IdleConnTimeout:       90 * time.Second,
			TLSHandshakeTimeout:   10 * time.Second,
			ExpectContinueTimeout: 1 * time.Second,
		},
		// IMPORTANT: Don't interfere with redirects - let client handle them
		CheckRedirect: func(req *http.Request, via []*http.Request) error {
			return http.ErrUseLastResponse
		},
		Timeout: 30 * time.Second,
	}

	// Make the request
	resp, err := client.Do(proxyReq)
	if err != nil {
		http.Error(w, err.Error(), http.StatusServiceUnavailable)
		return
	}
	defer resp.Body.Close()

	// Read response body for dumping
	respBody, err := io.ReadAll(resp.Body)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Dump traffic for inspection
	p.dumpTraffic(r, reqBody, respBody, r.Host)

	// Print traffic if domain is of interest
	if p.isDomainOfInterest(r.Host) {
		p.printTraffic(r, reqBody, respBody)
	}

	// Copy ALL response headers exactly as-is (completely transparent)
	for name, values := range resp.Header {
		w.Header()[name] = values
	}

	// Write the exact response status and body
	w.WriteHeader(resp.StatusCode)
	w.Write(respBody)
}

func (p *ProxyServer) copyAndDump(dst io.Writer, src io.Reader, host, direction string) {
	buffer := make([]byte, 32768) // Increased buffer size
	var allData []byte
	totalBytes := 0

	for {
		n, err := src.Read(buffer)
		if n > 0 {
			data := buffer[:n]
			written, writeErr := dst.Write(data)
			if writeErr != nil {
				fmt.Printf("Write error in %s direction for %s: %v\n", direction, host, writeErr)
				break
			}
			if written != n {
				fmt.Printf("Incomplete write in %s direction for %s: wrote %d of %d bytes\n", direction, host, written, n)
			}
			allData = append(allData, data...)
			totalBytes += n
		}
		if err != nil {
			if err != io.EOF {
				fmt.Printf("Read error in %s direction for %s: %v\n", direction, host, err)
			}
			break
		}
	}

	// Dump encrypted HTTPS traffic
	if len(allData) > 0 {
		p.dumpHTTPSTraffic(host, direction+"_encrypted", allData)

		// If domain is of interest, print to stdout
		if p.isDomainOfInterest(host) {
			fmt.Printf("\n=== HTTPS %s Encrypted Traffic: %s ===\n", direction, host)
			fmt.Printf("Data length: %d bytes\n", totalBytes)
			// Display first 256 bytes of encrypted data (hexadecimal format)
			displayLength := len(allData)
			if displayLength > 256 {
				displayLength = 256
			}
			fmt.Printf("Encrypted data content (first %d bytes): %x\n", displayLength, allData[:displayLength])
			fmt.Println("==========================================")
		}
	}
}

// copyAndDumpDecrypted copies and dumps decrypted data
func (p *ProxyServer) copyAndDumpDecrypted(dst io.Writer, src io.Reader, host, direction string) {
	buffer := make([]byte, 32768) // Increased buffer size
	var allData []byte
	totalBytes := 0

	for {
		n, err := src.Read(buffer)
		if n > 0 {
			data := buffer[:n]
			written, writeErr := dst.Write(data)
			if writeErr != nil {
				fmt.Printf("Write error in decrypted %s direction for %s: %v\n", direction, host, writeErr)
				break
			}
			if written != n {
				fmt.Printf("Incomplete write in decrypted %s direction for %s: wrote %d of %d bytes\n", direction, host, written, n)
			}
			allData = append(allData, data...)
			totalBytes += n
		}
		if err != nil {
			if err != io.EOF {
				fmt.Printf("Read error in decrypted %s direction for %s: %v\n", direction, host, err)
			}
			break
		}
	}

	// Dump decrypted HTTPS traffic
	if len(allData) > 0 {
		p.dumpHTTPSTraffic(host, direction+"_decrypted", allData)

		// If domain is of interest, print to stdout
		if p.isDomainOfInterest(host) {
			fmt.Printf("\n=== HTTPS %s Decrypted Traffic: %s ===\n", direction, host)
			fmt.Printf("Data length: %d bytes\n", totalBytes)
			// Display complete decrypted data (limit to first 2KB for readability)
			displayLength := len(allData)
			if displayLength > 2048 {
				displayLength = 2048
			}
			fmt.Printf("Decrypted data content (first %d bytes): %s\n", displayLength, string(allData[:displayLength]))
			fmt.Println("==========================================")
		}
	}
}

func (p *ProxyServer) dumpTraffic(req *http.Request, reqBody, respBody []byte, host string) {
	timestamp := time.Now().Format("20060102_150405")
	filename := fmt.Sprintf("%s_%s.txt", timestamp, sanitizeFilename(host))
	filepath := filepath.Join(p.config.Dump.OutputDir, filename)

	file, err := os.Create(filepath)
	if err != nil {
		log.Printf("Failed to create dump file: %v", err)
		return
	}
	defer file.Close()

	// Write request information
	fmt.Fprintf(file, "=== REQUEST ===\n")
	fmt.Fprintf(file, "%s %s %s\n", req.Method, req.URL.String(), req.Proto)
	fmt.Fprintf(file, "Host: %s\n", req.Host)
	for name, values := range req.Header {
		for _, value := range values {
			fmt.Fprintf(file, "%s: %s\n", name, value)
		}
	}
	fmt.Fprintf(file, "\n")

	// Write request body
	if len(reqBody) > 0 {
		fmt.Fprintf(file, "%s\n", string(reqBody))
	}

	// Write response information
	fmt.Fprintf(file, "\n=== RESPONSE ===\n")
	fmt.Fprintf(file, "%s\n", string(respBody))
}

func (p *ProxyServer) dumpHTTPSTraffic(host, direction string, data []byte) {
	timestamp := time.Now().Format("20060102_150405")
	filename := fmt.Sprintf("%s_%s_%s.bin", timestamp, sanitizeFilename(host), direction)
	filepath := filepath.Join(p.config.Dump.OutputDir, filename)

	file, err := os.Create(filepath)
	if err != nil {
		log.Printf("Failed to create HTTPS dump file: %v", err)
		return
	}
	defer file.Close()

	file.Write(data)
}

func (p *ProxyServer) isDomainOfInterest(host string) bool {
	// Remove port number
	if colonIndex := strings.Index(host, ":"); colonIndex != -1 {
		host = host[:colonIndex]
	}

	for _, domain := range p.config.DomainsOfInterest {
		if strings.Contains(host, domain) {
			return true
		}
	}
	return false
}

func (p *ProxyServer) printTraffic(req *http.Request, reqBody, respBody []byte) {
	fmt.Printf("\n=== Traffic from Domain of Interest: %s ===\n", req.Host)
	fmt.Printf("Request: %s %s\n", req.Method, req.URL.String())

	// Print request headers
	fmt.Println("Request Headers:")
	for name, values := range req.Header {
		for _, value := range values {
			fmt.Printf("  %s: %s\n", name, value)
		}
	}

	// Print complete request body
	if len(reqBody) > 0 {
		fmt.Printf("Request Body (%d bytes): %s\n", len(reqBody), string(reqBody))
	}

	// Print complete response body
	if len(respBody) > 0 {
		fmt.Printf("Response Body (%d bytes): %s\n", len(respBody), string(respBody))
	}
	fmt.Println("==========================================")
}

func sanitizeFilename(filename string) string {
	// Replace unsafe characters
	replacer := strings.NewReplacer(
		":", "_",
		"/", "_",
		"\\", "_",
		"*", "_",
		"?", "_",
		"\"", "_",
		"<", "_",
		">", "_",
		"|", "_",
	)
	return replacer.Replace(filename)
}

func (p *ProxyServer) setSystemProxy() error {
	// Get current proxy settings
	k, err := registry.OpenKey(registry.CURRENT_USER, `Software\Microsoft\Windows\CurrentVersion\Internet Settings`, registry.QUERY_VALUE)
	if err != nil {
		return err
	}
	defer k.Close()

	// Read current ProxyServer settings
	currentProxy, _, err := k.GetStringValue("ProxyServer")
	if err == nil {
		p.originalProxy = currentProxy
	}

	// Set new proxy
	k, err = registry.OpenKey(registry.CURRENT_USER, `Software\Microsoft\Windows\CurrentVersion\Internet Settings`, registry.SET_VALUE)
	if err != nil {
		return err
	}
	defer k.Close()

	proxyAddr := fmt.Sprintf("127.0.0.1:%d", p.config.Proxy.Port)

	// Enable proxy
	if err := k.SetDWordValue("ProxyEnable", 1); err != nil {
		return err
	}

	// Set proxy server address for BOTH HTTP and HTTPS
	// Format: "http=proxy:port;https=proxy:port" or just "proxy:port" for both
	if err := k.SetStringValue("ProxyServer", proxyAddr); err != nil {
		return err
	}

	// Ensure no proxy bypass for local addresses
	if err := k.SetStringValue("ProxyOverride", "<local>"); err != nil {
		// This is not critical, continue anyway
		fmt.Printf("Warning: Could not set ProxyOverride: %v\n", err)
	}

	// Refresh IE settings and notify system
	return p.refreshIESettings()
}

func (p *ProxyServer) restoreSystemProxy() error {
	k, err := registry.OpenKey(registry.CURRENT_USER, `Software\Microsoft\Windows\CurrentVersion\Internet Settings`, registry.SET_VALUE)
	if err != nil {
		return err
	}
	defer k.Close()

	// Disable proxy
	if err := k.SetDWordValue("ProxyEnable", 0); err != nil {
		return err
	}

	// Restore original proxy settings
	if p.originalProxy != "" {
		if err := k.SetStringValue("ProxyServer", p.originalProxy); err != nil {
			return err
		}
	}

	// Refresh IE settings
	return p.refreshIESettings()
}

func (p *ProxyServer) refreshIESettings() error {
	// Multiple methods to ensure Windows recognizes the proxy change

	// Method 1: Reset WinHTTP proxy
	cmd1 := exec.Command("cmd", "/c", "netsh winhttp reset proxy")
	if err := cmd1.Run(); err != nil {
		fmt.Printf("Warning: netsh winhttp reset failed: %v\n", err)
	}

	// Method 2: Import IE proxy settings to WinHTTP
	cmd2 := exec.Command("cmd", "/c", "netsh winhttp import proxy source=ie")
	if err := cmd2.Run(); err != nil {
		fmt.Printf("Warning: netsh winhttp import failed: %v\n", err)
	}

	// Method 3: Force refresh Internet Options
	cmd3 := exec.Command("cmd", "/c", "rundll32.exe inetcpl.cpl,ClearMyTracksByProcess 8")
	if err := cmd3.Run(); err != nil {
		fmt.Printf("Warning: Internet Options refresh failed: %v\n", err)
	}

	return nil
}

func (p *ProxyServer) verifyProxySettings() error {
	k, err := registry.OpenKey(registry.CURRENT_USER, `Software\Microsoft\Windows\CurrentVersion\Internet Settings`, registry.QUERY_VALUE)
	if err != nil {
		return fmt.Errorf("failed to open registry key: %v", err)
	}
	defer k.Close()

	// Check if proxy is enabled
	proxyEnable, _, err := k.GetIntegerValue("ProxyEnable")
	if err != nil {
		return fmt.Errorf("failed to read ProxyEnable: %v", err)
	}
	if proxyEnable != 1 {
		return fmt.Errorf("proxy is not enabled (ProxyEnable = %d)", proxyEnable)
	}

	// Check proxy server setting
	proxyServer, _, err := k.GetStringValue("ProxyServer")
	if err != nil {
		return fmt.Errorf("failed to read ProxyServer: %v", err)
	}

	expectedProxy := fmt.Sprintf("127.0.0.1:%d", p.config.Proxy.Port)
	if proxyServer != expectedProxy {
		return fmt.Errorf("proxy server mismatch: expected %s, got %s", expectedProxy, proxyServer)
	}

	return nil
}

func (p *ProxyServer) showProxyConfiguration() {
	fmt.Printf("🔍 Current Proxy Configuration:\n")

	// Show Windows proxy settings
	k, err := registry.OpenKey(registry.CURRENT_USER, `Software\Microsoft\Windows\CurrentVersion\Internet Settings`, registry.QUERY_VALUE)
	if err != nil {
		fmt.Printf("   ❌ Could not read proxy settings: %v\n", err)
		return
	}
	defer k.Close()

	if proxyEnable, _, err := k.GetIntegerValue("ProxyEnable"); err == nil {
		fmt.Printf("   ProxyEnable: %d\n", proxyEnable)
	}

	if proxyServer, _, err := k.GetStringValue("ProxyServer"); err == nil {
		fmt.Printf("   ProxyServer: %s\n", proxyServer)
	}

	if proxyOverride, _, err := k.GetStringValue("ProxyOverride"); err == nil {
		fmt.Printf("   ProxyOverride: %s\n", proxyOverride)
	}

	// Show WinHTTP proxy settings
	fmt.Printf("   WinHTTP Proxy Settings:\n")
	cmd := exec.Command("cmd", "/c", "netsh winhttp show proxy")
	if output, err := cmd.CombinedOutput(); err == nil {
		fmt.Printf("   %s\n", string(output))
	} else {
		fmt.Printf("   ❌ Could not get WinHTTP proxy settings: %v\n", err)
	}
}

func (p *ProxyServer) installCACert() error {
	// Use hardcoded CA certificate data
	certData := []byte(getHardcodedCACert())

	// Parse certificate
	var cert *x509.Certificate
	var err error

	// Try parsing DER format directly
	cert, err = x509.ParseCertificate(certData)
	if err != nil {
		// Try parsing PEM format
		block, _ := pem.Decode(certData)
		if block == nil {
			return fmt.Errorf("unable to parse certificate file")
		}
		cert, err = x509.ParseCertificate(block.Bytes)
		if err != nil {
			return err
		}
	}

	// Write certificate to temporary file
	tempFile, err := os.CreateTemp("", "ca_cert_*.crt")
	if err != nil {
		return err
	}
	tempFileName := tempFile.Name()
	defer os.Remove(tempFileName)

	if err := pem.Encode(tempFile, &pem.Block{
		Type:  "CERTIFICATE",
		Bytes: cert.Raw,
	}); err != nil {
		tempFile.Close()
		return err
	}

	// Close the file before certutil accesses it to avoid sharing violation
	tempFile.Close()

	// Use certutil to install certificate to trusted root certificate authorities
	cmd := exec.Command("certutil", "-addstore", "-f", "Root", tempFileName)
	output, err := cmd.CombinedOutput()
	if err != nil {
		return fmt.Errorf("failed to install certificate: %v, output: %s", err, string(output))
	}

	return nil
}

// setConsoleUTF8 sets the Windows console to UTF-8 code page to prevent garbled text
func setConsoleUTF8() {
	// Set console input and output code page to UTF-8 (65001)
	cmd := exec.Command("cmd", "/c", "chcp 65001 >nul")
	cmd.Run()
}

// testBasicConnectivity tests if the proxy server is responding to basic HTTP requests
func testBasicConnectivity(port int) error {
	client := &http.Client{
		Timeout: 5 * time.Second,
	}

	healthURL := fmt.Sprintf("http://127.0.0.1:%d/proxy-health", port)
	resp, err := client.Get(healthURL)
	if err != nil {
		return fmt.Errorf("failed to connect to proxy health endpoint: %v", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return fmt.Errorf("proxy health check returned status %d", resp.StatusCode)
	}

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return fmt.Errorf("failed to read health check response: %v", err)
	}

	if !strings.Contains(string(body), "MITM Proxy is running") {
		return fmt.Errorf("unexpected health check response: %s", string(body))
	}

	return nil
}

// testProxyConnectivity tests the proxy with simple HTTP and HTTPS requests
func testProxyConnectivity(proxyAddr string) {
	fmt.Println("🧪 Testing proxy connectivity...")

	// Create proxy URL
	proxyURL, err := url.Parse(fmt.Sprintf("http://%s", proxyAddr))
	if err != nil {
		fmt.Printf("❌ Failed to parse proxy URL: %v\n", err)
		return
	}

	// Create HTTP client with proxy
	transport := &http.Transport{
		Proxy: http.ProxyURL(proxyURL),
		TLSClientConfig: &tls.Config{
			InsecureSkipVerify: true,
		},
	}
	client := &http.Client{
		Transport: transport,
		Timeout:   30 * time.Second,
	}

	// Test HTTP request
	fmt.Println("🌐 Testing HTTP request...")
	testHTTPRequest(client, "http://httpbin.org/ip")

	// Test HTTPS request
	fmt.Println("🔒 Testing HTTPS request...")
	testHTTPSRequest(client, "https://httpbin.org/ip")

	// Test redirects (should be transparent)
	fmt.Println("🔄 Testing HTTP redirect...")
	testRedirectTransparency(client, "http://httpbin.org/redirect/1")

	// Test domain that might cause issues
	fmt.Println("🌍 Testing Google...")
	testHTTPSRequest(client, "https://www.google.com")
}

func testHTTPRequest(client *http.Client, testURL string) {
	resp, err := client.Get(testURL)
	if err != nil {
		fmt.Printf("❌ HTTP test failed: %v\n", err)
		return
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		fmt.Printf("❌ Failed to read HTTP response: %v\n", err)
		return
	}

	fmt.Printf("✅ HTTP test successful: %s\n", resp.Status)
	fmt.Printf("   Response: %s\n", string(body)[:min(len(body), 200)])
}

func testHTTPSRequest(client *http.Client, testURL string) {
	resp, err := client.Get(testURL)
	if err != nil {
		fmt.Printf("❌ HTTPS test failed: %v\n", err)
		return
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		fmt.Printf("❌ Failed to read HTTPS response: %v\n", err)
		return
	}

	fmt.Printf("✅ HTTPS test successful: %s\n", resp.Status)
	fmt.Printf("   Response: %s\n", string(body)[:min(len(body), 200)])
}

func testRedirectTransparency(client *http.Client, testURL string) {
	// Create a client that doesn't follow redirects to test transparency
	testClient := &http.Client{
		Transport: client.Transport,
		CheckRedirect: func(req *http.Request, via []*http.Request) error {
			return http.ErrUseLastResponse
		},
		Timeout: client.Timeout,
	}

	resp, err := testClient.Get(testURL)
	if err != nil {
		fmt.Printf("❌ Redirect transparency test failed: %v\n", err)
		return
	}
	defer resp.Body.Close()

	if resp.StatusCode >= 300 && resp.StatusCode < 400 {
		location := resp.Header.Get("Location")
		fmt.Printf("✅ Redirect transparency test successful: %s -> %s\n", resp.Status, location)
	} else {
		fmt.Printf("⚠️  Expected redirect, got: %s (this may be normal)\n", resp.Status)
	}
}

func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}