/*! @file

    @id $Id$
*/
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#ifndef __OPENSSL_HXX__
#define __OPENSSL_HXX__

#include <openssl/pkcs12.h>
#include <openssl/x509.h>

#include "openssl/bio.h"
#include "openssl/ssl.h"
#include <openssl/err.h>
#include <cstdio>

/*! @defgroup gopenssl C++ Wrapper around OpenSSL API */
//@{
//! @defgroup openssllib OpenSSL C++ Library
//! @defgroup opensslexceptions OpenSSL Exceptions

//! @see gopenssl
namespace openssl {


  //============================================================================
  //! @addtogroup opensslexceptions
  //@{

  //----------------------------------------------------------------------------
  class exception: public std::exception {
    public:
      exception(const std::string& reason) throw():
          _what("openssl: "+reason) {
      }
      ~exception() throw() {}
      const char* what() const throw() {
        return _what.c_str();
      }
    private:
      std::string _what;
  };
  //----------------------------------------------------------------------------
  class openssl_error: public exception {
    public:
      openssl_error(const std::string& reason) throw():
          exception(reason+'\n'+ERR_error_string(ERR_get_error(), 0)) {
      }
  };
  //----------------------------------------------------------------------------
  class pkcs12_error: public openssl_error {
    public:
      pkcs12_error(const std::string& reason) throw():
          openssl_error("pkcs12: "+reason) {
      }
  };
  //----------------------------------------------------------------------------
  class x509_error: public openssl_error {
    public:
      x509_error(const std::string& reason) throw():
          openssl_error("x509: "+reason) {
      }
  };
  //----------------------------------------------------------------------------
  class bio_error: public openssl_error {
    public:
      bio_error(const std::string& reason) throw():
          openssl_error("bio: "+reason) {
      }
  };
  //----------------------------------------------------------------------------
  class ssl_error: public openssl_error {
    public:
      ssl_error(const std::string& reason) throw():
          openssl_error("ssl: "+reason) {
      }
  };
  //----------------------------------------------------------------------------
  class allocation_failed: public x509_error {
    public:
      allocation_failed() throw():
          x509_error("memory allocation failed") {
      }
  };
  //----------------------------------------------------------------------------
  class undefined_certificate: public x509_error {
    public:
      undefined_certificate() throw():
          x509_error("certificate must not be 0") {
      }
  };
  //----------------------------------------------------------------------------
  class x509_parsing_failed: public x509_error {
    public:
      x509_parsing_failed() throw():
          x509_error("parsing DER encoded certificate failed") {
      }
  };
  //----------------------------------------------------------------------------
  class x509_copy_failed: public x509_error {
    public:
      x509_copy_failed() throw():
          x509_error("certificate object copy failed") {
      }
  };
  //----------------------------------------------------------------------------
  class pkcs12_reading_failed: public pkcs12_error {
    public:
      pkcs12_reading_failed(const std::string& file) throw():
          pkcs12_error("reading DER encoded p12 file failed: "+file) {
      }
  };
  //----------------------------------------------------------------------------
  class pkcs12_parsing_failed: public pkcs12_error {
    public:
      pkcs12_parsing_failed(const std::string& file) throw():
          pkcs12_error("parsing DER encoded p12 file failed: "+file) {
      }
  };
  //----------------------------------------------------------------------------
  class pkcs12_no_private_key: public pkcs12_error {
    public:
      pkcs12_no_private_key() throw(): pkcs12_error("no private key") {}
  };
  //----------------------------------------------------------------------------
  class pkcs12_no_x509: public pkcs12_error {
    public:
      pkcs12_no_x509() throw(): pkcs12_error("no x509 certificate") {}
  };
  //----------------------------------------------------------------------------
  class cannot_open_file: public exception {
    public:
      cannot_open_file(const std::string& file) throw():
          exception("cannot open file: "+file) {
      }
  };
  //----------------------------------------------------------------------------
  class bio_connection_failed: public bio_error {
    public:
      bio_connection_failed(const std::string& hostPort) throw():
          bio_error("connection failed to: "+hostPort) {
      }
  };
  //----------------------------------------------------------------------------
  class bio_closed_connection: public bio_error {
    public:
      bio_closed_connection() throw(): bio_error("closed connection") {}
  };
  //----------------------------------------------------------------------------
  class bio_read_error: public bio_error {
    public:
      bio_read_error() throw(): bio_error("read error") {}
  };
  //----------------------------------------------------------------------------
  class bio_write_error: public bio_error {
    public:
      bio_write_error() throw(): bio_error("write error") {}
  };
  //----------------------------------------------------------------------------
  class ssl_cannot_create_context: public ssl_error {
    public:
      ssl_cannot_create_context() throw(): ssl_error("cannot create context") {}
  };
  //----------------------------------------------------------------------------
  class ssl_certificate_file_not_loaded: public ssl_error {
    public:
      ssl_certificate_file_not_loaded(const std::string& file) throw():
          ssl_error("certificate file not loaded: "+file) {
      }
  };
  //----------------------------------------------------------------------------
  class ssl_certificate_folder_not_loaded: public ssl_error {
    public:
      ssl_certificate_folder_not_loaded(const std::string& path) throw():
          ssl_error("certificate folder not loaded: "+path) {
      }
  };
  //@}

  //! @addtogroup openssllib
  //@{
  
  //============================================================================
  class Init {
    public:
      Init() {
        SSL_load_error_strings();
        ERR_load_BIO_strings();
        OpenSSL_add_all_algorithms();
      }
  };

  //============================================================================
  class X509 {
    public:
      //! Construct empty certificate.
      X509(): _x509(X509_new()) {
        if (!_x509) throw allocation_failed();
      }
      X509(const X509& o): _x509(0) {
        unsigned char* d(0);
        int len(i2d_X509(o._x509, &d));
        if (!len) throw x509_copy_failed();
        const unsigned char* d2(d);
        _x509 = d2i_X509(0, &d2, len);
        free(d);
        if (!_x509) throw x509_copy_failed();
      }
      //! Take over OpenSSL allocated certificate.
      X509(::X509 *x509): _x509(x509) {
        if (!_x509) throw undefined_certificate();
      }
      ~X509() {
        X509_free(_x509);
      }
      X509& operator=(const X509& o) {
        X509_free(_x509);
        _x509 = 0;
        unsigned char* d(0);
        int len(i2d_X509(o._x509, &d));
        if (!len) throw x509_copy_failed();
        const unsigned char* d2(d);
        free(d);
        _x509 = d2i_X509(0, &d2, len);
        if (!_x509) throw x509_copy_failed();
      }
    private:
      ::X509* _x509;
  };

  //============================================================================
  class PrivateKey {
    public:
      PrivateKey(EVP_PKEY *) {
      }
  };

  //============================================================================
  class PKCS12 {
      
      //...............................................................typedefs
    public:
      typedef std::vector<X509*> X509List;
      
      //................................................................methods
    public:

      //! Read from a PKCS#12 (.p12) file.
      PKCS12(std::string filename, std::string password):
          _key(0), _cert(0) {
        FILE* file(fopen(filename.c_str(), "rb"));
        if (!file) throw cannot_open_file(filename);
        ::PKCS12 *p12(d2i_PKCS12_fp(file, 0));
        fclose(file);
        if (!p12) throw pkcs12_reading_failed(filename);
        try {
          EVP_PKEY *pkey(0);
          ::X509 *cert(0);
          STACK_OF(X509) *ca(0);
          if (!PKCS12_parse(p12, password.c_str(), &pkey, &cert, &ca))
            throw pkcs12_parsing_failed(filename);
          if (pkey) _key = new PrivateKey(pkey);
          if (cert) _cert = new X509(cert);
          for (int i(sk_num(ca)); i>0; --i)
            _ca.push_back(new X509((::X509*)sk_pop(ca)));
          PKCS12_free(p12);
        } catch (...) {
          PKCS12_free(p12);
          throw;
        }
      }
      
      ~PKCS12() {
        delete _key;
        delete _cert;
        for (X509List::iterator it(_ca.begin()); it!=_ca.end(); ++it)
          delete *it;
      }

      bool hasPrivateKey() {
        return _key;
      }

      bool hasCert() {
        return _cert;
      }

      const PrivateKey& privateKey() {
        if (!_key) throw pkcs12_no_private_key();
        return *_key;
      };

      const X509& x509() {
        if (!_cert) throw pkcs12_no_x509();
        return *_cert;
      };

      const X509List& ca() const {
        return _ca;
      }
      
    private:
      PrivateKey *_key;
      X509 *_cert;
      X509List _ca;
  };

  //============================================================================
  class BIO {

    private:

      BIO(const BIO&);
      BIO& operator=(const BIO&);
      
    public:
      
      BIO(): _bio(0) {}
      
      ~BIO() {
        try {
          close();
        } catch (...) {
          if (!std::uncaught_exception()) throw;
        }
      }
      
      BIO& connect(const std::string& hostPort) {
        close();
        if (!(_bio=BIO_new_connect(const_cast<char*>(hostPort.c_str()))) ||
            BIO_do_connect(_bio)<=0)
          throw bio_connection_failed(hostPort);
        return *this;
      }
      
      BIO& operator>>(std::string& s) {
        s += read();
        return *this;
      }
      
      BIO& operator<<(const std::string& s) {
        return write(s);
      }

      /*! @todo How can I find out, whether there's still data
          available, or whether a response has been finished and
          server is waiting for next request, but connection is still
          open? */
      std::string read() {
        if (!_bio) throw bio_closed_connection();
        const int BUFF_SZ(1024);
        char buff[BUFF_SZ];
        int x(BIO_read(_bio, buff, BUFF_SZ));
        if (x<=0)
          if (BIO_should_retry(_bio)) return read();
          else throw bio_read_error();
        return std::string(buff, x);
      }

      BIO& write(const std::string& s) {
        int x(BIO_write(_bio, s.begin().operator->(), s.size()));
        if (x<=0)
          if (BIO_should_retry(_bio)) return write(s);
          else throw bio_write_error();
        else
          if (x<s.size()) return write(s.substr(x));
        return *this;
      }
      
      void close() {
        BIO_free_all(_bio);
      }
      
    private:
      
      friend class SSL;
      ::BIO* _bio;
      
  };

  //! Read authorized certificate from a single pem file.
  class TrustStore {
    public:
      TrustStore(const std::string& pathToPemFile):
          _file(pathToPemFile) {
      }
      const std::string& file() const {
        return _file;
      }
    private:
      std::string _file;
  };

  class CertificateFolder {
    public:
      CertificateFolder(const std::string& certificateFolder):
          _path(certificateFolder) {
      }
      const std::string& path() const {
        return _path;
      }
    private:
      std::string _path;
  };

  class SSL {
    private:
      SSL();
      SSL(const SSL&);
      SSL& operator=(const SSL&);
    public:
      SSL(const TrustStore& file):
          _ctx(SSL_CTX_new(SSLv23_client_method())),
          _ssl(0) {
        if (!_ctx) throw ssl_cannot_create_context();
        if (!SSL_CTX_load_verify_locations(_ctx, file.file().c_str(), 0))
          throw ssl_certificate_file_not_loaded(file.file());
      }
      SSL(const CertificateFolder& folder):
          _ctx(SSL_CTX_new(SSLv23_client_method())),
          _ssl(0) {
        if (!_ctx) throw ssl_cannot_create_context();
        if (!SSL_CTX_load_verify_locations(_ctx, 0, folder.path().c_str()))
          throw ssl_certificate_folder_not_loaded(folder.path());
      }
      ~SSL() {
        close();
        SSL_CTX_free(_ctx);
      }
      BIO& connect(const std::string& hostPort) {
        close();
        if (!(_bio._bio=BIO_new_ssl_connect(_ctx)))
          throw bio_connection_failed(hostPort);
        BIO_get_ssl(_bio._bio, &_ssl);
        if (!_ssl) 
        SSL_set_mode(_ssl, SSL_MODE_AUTO_RETRY);
        BIO_set_conn_hostname(_bio._bio, const_cast<char*>(hostPort.c_str()));
        if (BIO_do_connect(_bio._bio)<=0) throw bio_connection_failed(hostPort);
        return _bio;
      }
      SSL& close() {
        _bio.close();
        _ssl = 0; //! @todo is this correct? <--
        return *this;
      }
      bool verifyResult() {
        return _ssl && SSL_get_verify_result(_ssl)==X509_V_OK;
      }
    private:
      SSL_CTX *_ctx;
      ::SSL *_ssl;
      BIO _bio;
  };
  
  //@}
  
}
//@}

#endif