/* encrypt.c - Encrypt function.
   Copyright (C) 2000 Werner Koch (dd9jn)
   Copyright (C) 2001, 2002, 2003, 2004 g10 Code GmbH

   This file is part of GPGME.
 
   GPGME is free software; you can redistribute it and/or modify it
   under the terms of the GNU Lesser General Public License as
   published by the Free Software Foundation; either version 2.1 of
   the License, or (at your option) any later version.
   
   GPGME is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.
   
   You should have received a copy of the GNU Lesser General Public
   License along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
   02111-1307, USA.  */

#if HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdlib.h>
#include <string.h>
#include <errno.h>

#include "gpgme.h"
#include "context.h"
#include "ops.h"


typedef struct
{
  struct _gpgme_op_encrypt_result result;

  /* A pointer to the next pointer of the last invalid recipient in
     the list.  This makes appending new invalid recipients painless
     while preserving the order.  */
  gpgme_invalid_key_t *lastp;
} *op_data_t;


static void
release_op_data (void *hook)
{
  op_data_t opd = (op_data_t) hook;
  gpgme_invalid_key_t invalid_recipient = opd->result.invalid_recipients;

  while (invalid_recipient)
    {
      gpgme_invalid_key_t next = invalid_recipient->next;
      if (invalid_recipient->fpr)
	free (invalid_recipient->fpr);
      invalid_recipient = next;
    }
}


gpgme_encrypt_result_t
gpgme_op_encrypt_result (gpgme_ctx_t ctx)
{
  void *hook;
  op_data_t opd;
  gpgme_error_t err;

  err = _gpgme_op_data_lookup (ctx, OPDATA_ENCRYPT, &hook, -1, NULL);
  opd = hook;

  if (err || !opd)
    return NULL;

  return &opd->result;
}


gpgme_error_t
_gpgme_encrypt_status_handler (void *priv, gpgme_status_code_t code,
			       char *args)
{
  gpgme_ctx_t ctx = (gpgme_ctx_t) priv;
  gpgme_error_t err;
  void *hook;
  op_data_t opd;

  err = _gpgme_op_data_lookup (ctx, OPDATA_ENCRYPT, &hook, -1, NULL);
  opd = hook;
  if (err)
    return err;

  switch (code)
    {
    case GPGME_STATUS_EOF:
      if (opd->result.invalid_recipients)
	return gpg_error (GPG_ERR_UNUSABLE_PUBKEY);
      break;

    case GPGME_STATUS_INV_RECP:
      err = _gpgme_parse_inv_recp (args, opd->lastp);
      if (err)
	return err;

      opd->lastp = &(*opd->lastp)->next;
      break;

    case GPGME_STATUS_NO_RECP:
      /* Should not happen, because we require at least one recipient.  */
      return gpg_error (GPG_ERR_GENERAL);

    default:
      break;
    }
  return 0;
}


static gpgme_error_t
encrypt_sym_status_handler (void *priv, gpgme_status_code_t code, char *args)
{
  gpgme_error_t err;

  err = _gpgme_progress_status_handler (priv, code, args);
  if (!err)
    err = _gpgme_passphrase_status_handler (priv, code, args);
  return err;
}


static gpgme_error_t
encrypt_status_handler (void *priv, gpgme_status_code_t code, char *args)
{
  return _gpgme_progress_status_handler (priv, code, args)
    || _gpgme_encrypt_status_handler (priv, code, args);
}


gpgme_error_t
_gpgme_op_encrypt_init_result (gpgme_ctx_t ctx)
{
  gpgme_error_t err;
  void *hook;
  op_data_t opd;

  err = _gpgme_op_data_lookup (ctx, OPDATA_ENCRYPT, &hook, sizeof (*opd),
			       release_op_data);
  opd = hook;
  if (err)
    return err;

  opd->lastp = &opd->result.invalid_recipients;
  return 0;
}


static gpgme_error_t
encrypt_start (gpgme_ctx_t ctx, int synchronous, gpgme_key_t recp[],
	       gpgme_encrypt_flags_t flags,
	       gpgme_data_t plain, gpgme_data_t cipher)
{
  gpgme_error_t err;
  int symmetric = 0;

  err = _gpgme_op_reset (ctx, synchronous);
  if (err)
    return err;

  err = _gpgme_op_encrypt_init_result (ctx);
  if (err)
    return err;

  if (!recp)
    symmetric = 1;

  if (!plain)
    return gpg_error (GPG_ERR_NO_DATA);
  if (!cipher)
    return gpg_error (GPG_ERR_INV_VALUE);
  if (recp && ! *recp)
    return gpg_error (GPG_ERR_INV_VALUE);

  if (symmetric && ctx->passphrase_cb)
    {
      /* Symmetric encryption requires a passphrase.  */
      err = _gpgme_engine_set_command_handler
	(ctx->engine, _gpgme_passphrase_command_handler, ctx, NULL);
      if (err)
	return err;
    }

  _gpgme_engine_set_status_handler (ctx->engine,
				    symmetric
				    ? encrypt_sym_status_handler
				    : encrypt_status_handler,
				    ctx);

  return _gpgme_engine_op_encrypt (ctx->engine, recp, flags, plain, cipher,
				   ctx->use_armor);
}


gpgme_error_t
gpgme_op_encrypt_start (gpgme_ctx_t ctx, gpgme_key_t recp[],
			gpgme_encrypt_flags_t flags,
			gpgme_data_t plain, gpgme_data_t cipher)
{
  return encrypt_start (ctx, 0, recp, flags, plain, cipher);
}


/* Encrypt plaintext PLAIN within CTX for the recipients RECP and
   store the resulting ciphertext in CIPHER.  */
gpgme_error_t
gpgme_op_encrypt (gpgme_ctx_t ctx, gpgme_key_t recp[],
		  gpgme_encrypt_flags_t flags,
		  gpgme_data_t plain, gpgme_data_t cipher)
{
  gpgme_error_t err = encrypt_start (ctx, 1, recp, flags, plain, cipher);
  if (!err)
    err = _gpgme_wait_one (ctx);
  return err;
}