package main

import (
	"crypto/rand"
	"crypto/rsa"
	"crypto/x509"
	"crypto/x509/pkix"
	"encoding/pem"
	"log"
	"math/big"
	"net"
	"os"
	"path/filepath"
	"time"
)

func main() {
	certDir := "testdata/certificate"

	if err := os.MkdirAll(certDir, 0755); err != nil {
		log.Fatalf("Failed to create directory %s: %v", certDir, err)
	}

	template := &x509.Certificate{
		SerialNumber: big.NewInt(1),
		Subject: pkix.Name{
			Organization: []string{"Gin Test"},
			CommonName:   "localhost",
		},
		NotBefore: time.Now(),
		NotAfter:  time.Now().Add(365 * 24 * time.Hour), // 1 year validity

		KeyUsage:              x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
		ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
		BasicConstraintsValid: true,
		DNSNames:              []string{"localhost"},
		IPAddresses:           []net.IP{net.IPv4(127, 0, 0, 1), net.IPv6loopback},
	}

	privateKey, err := rsa.GenerateKey(rand.Reader, 2048)
	if err != nil {
		log.Fatalf("Failed to generate private key: %v", err)
	}

	derBytes, err := x509.CreateCertificate(rand.Reader, template, template, &privateKey.PublicKey, privateKey)
	if err != nil {
		log.Fatalf("Failed to create certificate: %v", err)
	}

	certPath := filepath.Join(certDir, "cert.pem")
	certOut, err := os.Create(certPath)
	if err != nil {
		log.Fatalf("Failed to open %s for writing: %v", certPath, err)
	}
	if err := pem.Encode(certOut, &pem.Block{Type: "CERTIFICATE", Bytes: derBytes}); err != nil {
		log.Fatalf("Failed to write data to %s: %v", certPath, err)
	}
	if err := certOut.Close(); err != nil {
		log.Fatalf("Error closing %s: %v", certPath, err)
	}
	log.Printf("Wrote %s\n", certPath)

	keyPath := filepath.Join(certDir, "key.pem")
	keyOut, err := os.OpenFile(keyPath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
	if err != nil {
		log.Fatalf("Failed to open %s for writing: %v", keyPath, err)
	}
	privBytes := x509.MarshalPKCS1PrivateKey(privateKey)
	if err := pem.Encode(keyOut, &pem.Block{Type: "RSA PRIVATE KEY", Bytes: privBytes}); err != nil {
		log.Fatalf("Failed to write data to %s: %v", keyPath, err)
	}
	if err := keyOut.Close(); err != nil {
		log.Fatalf("Error closing %s: %v", keyPath, err)
	}
	log.Printf("Wrote %s\n", keyPath)
}