package api

import (
	"crypto/rand"
	"crypto/rsa"
	"crypto/x509"
	"crypto/x509/pkix"
	"encoding/json"
	"encoding/pem"
	"errors"
	"fmt"
	"math/big"
	"net/http"
	"os"
	"scm/model"
	"time"

	"github.com/youmark/pkcs8"
)

func CreateCert(w http.ResponseWriter, r *http.Request) {
	var requestData model.CreateCertificateRequest
	if err := json.NewDecoder(r.Body).Decode(&requestData); err != nil {
		http.Error(w, "invalid JSON format", http.StatusBadRequest)
		return
	}
	caCert, caKey, err := loadCertAndKey(
		fmt.Sprintf(
			"%s/%s/%s.crt",
			os.Getenv("CERTS_PATH"),
			"root",
			"TolaMironcenkoCA",
		),
		fmt.Sprintf(
			"%s/%s/%s.key",
			os.Getenv("CERTS_PATH"),
			"root",
			"TolaMironcenkoCA",
		),
		requestData.CAKeyPassword,
	)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		fmt.Println("error loading certificate and key:", err)
		return
	}
	// TODO: Implement create certificate endpoint
	serverKey, err := rsa.GenerateKey(rand.Reader, 2048)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		fmt.Println("error generating server key:", err)
		return
	}
	serverCert, err := createServerCert(caCert, caKey, serverKey, requestData)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		fmt.Println("error creating server certificate:", err)
		return
	}
	_, err = os.Stat(fmt.Sprintf("%s/%s", os.Getenv("CERTS_PATH"), requestData.DNSNames[0]))
	if err == nil {
		http.Error(w, "certificate already exists", http.StatusConflict)
		fmt.Println("certificate already exists")
		return
	} else if os.IsNotExist(err) {
		err := os.Mkdir(fmt.Sprintf("%s/%s", os.Getenv("CERTS_PATH"), requestData.DNSNames[0]), 0755)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			fmt.Println("error creating directory:", err)
			return
		}
	} else {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		fmt.Println("error checking certificate directory:", err)
		return
	}
	err = savePEM(fmt.Sprintf("%s/%s/%s.crt", os.Getenv("CERTS_PATH"), requestData.DNSNames[0], requestData.DNSNames[0]), "CERTIFICATE", serverCert)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		fmt.Println("error saving certificate:", err)
		return
	}
	err = savePEM(fmt.Sprintf("%s/%s/%s.key", os.Getenv("CERTS_PATH"), requestData.DNSNames[0], requestData.DNSNames[0]), "RSA PRIVATE KEY", x509.MarshalPKCS1PrivateKey(serverKey))
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		fmt.Println("error saving private key:", err)
		return
	}
	fmt.Fprintf(w, "%s", `{"status": "success", "message": "Certificate created successfully"}`)
}

func createServerCert(
	caCert *x509.Certificate,
	caKey *rsa.PrivateKey,
	serverKey *rsa.PrivateKey,
	certdata model.CreateCertificateRequest,
) ([]byte, error) {
	// Шаблон серверного сертификата
	template := x509.Certificate{
		SerialNumber: big.NewInt(time.Now().Unix()),
		Subject: pkix.Name{
			Organization:       certdata.OrganizationName,
			CommonName:         certdata.CommonName,
			OrganizationalUnit: certdata.OrganizationUnit,
		},
		NotBefore:   time.Now(),
		NotAfter:    time.Now().AddDate(1, 0, 0), // 1 год
		KeyUsage:    x509.KeyUsageDigitalSignature | x509.KeyUsageKeyEncipherment,
		ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
		DNSNames:    certdata.DNSNames,
	}

	// Создаем сертификат, подписанный CA
	return x509.CreateCertificate(
		rand.Reader,
		&template,
		caCert,
		&serverKey.PublicKey,
		caKey,
	)
}

func loadCertAndKey(certFile, keyFile, password string) (*x509.Certificate, *rsa.PrivateKey, error) {
	fmt.Println(certFile, keyFile)
	// Загрузка корневого сертификата
	caCertPEM, err := os.ReadFile(certFile)
	if err != nil {
		return nil, nil, err
	}

	block, _ := pem.Decode(caCertPEM)
	if block == nil {
		return nil, nil, errors.New("failed to parse CA certificate PEM")
	}

	caCert, err := x509.ParseCertificate(block.Bytes)
	if err != nil {
		return nil, nil, err
	}

	// Загрузка зашифрованного приватного ключа
	keyPEM, err := os.ReadFile(keyFile)
	if err != nil {
		return nil, nil, err
	}

	block, _ = pem.Decode(keyPEM)
	if block == nil {
		return nil, nil, errors.New("failed to parse CA key PEM")
	}
	fmt.Print(block.Type)
	// Декодирование ключа с паролем
	decryptedKey, err := pkcs8.ParsePKCS8PrivateKey(block.Bytes, []byte(password))
	if err != nil {
		return nil, nil, fmt.Errorf("failed to decrypt CA key: %v", err)
	}

	caKey, ok := decryptedKey.(*rsa.PrivateKey)
	if !ok {
		return nil, nil, err
	}

	return caCert, caKey, nil
}

func savePEM(filename, blockType string, data []byte) error {
	file, err := os.Create(filename)
	if err != nil {
		return err
	}
	defer file.Close()

	err = pem.Encode(file, &pem.Block{
		Type:  blockType,
		Bytes: data,
	})
	if err != nil {
		return err
	}
	return nil
}