/*
     This file is part of GNUnet.
     Copyright (C) 2001, 2002, 2004, 2005, 2006, 2007, 2009 GNUnet e.V.

     GNUnet is free software: you can redistribute it and/or modify it
     under the terms of the GNU Affero General Public License as published
     by the Free Software Foundation, either version 3 of the License,
     or (at your option) any later version.

     GNUnet 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
     Affero General Public License for more details.

     You should have received a copy of the GNU Affero General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.

     SPDX-License-Identifier: AGPL3.0-or-later
 */
/**
 * @file fs/gnunet-download.c
 * @brief downloading for files on GNUnet
 * @author Christian Grothoff
 * @author Krista Bennett
 * @author James Blackwell
 * @author Igor Wronsky
 */
#include "platform.h"
#include "gnunet_fs_service.h"

static int ret;

static unsigned int verbose;

static int delete_incomplete;

static const struct GNUNET_CONFIGURATION_Handle *cfg;

static struct GNUNET_FS_Handle *ctx;

static struct GNUNET_FS_DownloadContext *dc;

static unsigned int anonymity = 1;

static unsigned int parallelism = 16;

static unsigned int request_parallelism = 4092;

static int do_recursive;

static char *filename;

static int local_only;


static void
cleanup_task (void *cls)
{
  GNUNET_FS_stop (ctx);
  ctx = NULL;
}


static void
shutdown_task (void *cls)
{
  if (NULL != dc)
  {
    GNUNET_FS_download_stop (dc, delete_incomplete);
    dc = NULL;
  }
}


/**
 * Display progress bar (if tty).
 *
 * @param x current position in the download
 * @param n total size of the download
 * @param w desired number of steps in the progress bar
 */
static void
display_bar (unsigned long long x, unsigned long long n, unsigned int w)
{
  char buf[w + 20];
  unsigned int p;
  unsigned int endeq;
  float ratio_complete;

  if (0 == isatty (1))
    return;
  ratio_complete = x / (float) n;
  endeq = ratio_complete * w;
  GNUNET_snprintf (buf, sizeof(buf), "%3d%% [", (int) (ratio_complete * 100));
  for (p = 0; p < endeq; p++)
    strcat (buf, "=");
  for (p = endeq; p < w; p++)
    strcat (buf, " ");
  strcat (buf, "]\r");
  printf ("%s", buf);
  fflush (stdout);
}


/**
 * Called by FS client to give information about the progress of an
 * operation.
 *
 * @param cls closure
 * @param info details about the event, specifying the event type
 *        and various bits about the event
 * @return client-context (for the next progress call
 *         for this operation; should be set to NULL for
 *         SUSPEND and STOPPED events).  The value returned
 *         will be passed to future callbacks in the respective
 *         field in the `struct GNUNET_FS_ProgressInfo`
 */
static void *
progress_cb (void *cls, const struct GNUNET_FS_ProgressInfo *info)
{
  char *s;
  const char *s2;
  char *t;

  switch (info->status)
  {
  case GNUNET_FS_STATUS_DOWNLOAD_START:
    if (verbose > 1)
      fprintf (stderr,
               _ ("Starting download `%s'.\n"),
               info->value.download.filename);
    break;

  case GNUNET_FS_STATUS_DOWNLOAD_PROGRESS:
    if (verbose)
    {
      s = GNUNET_strdup (
        GNUNET_STRINGS_relative_time_to_string (info->value.download.eta,
                                                GNUNET_YES));
      if (info->value.download.specifics.progress.block_download_duration
          .rel_value_us == GNUNET_TIME_UNIT_FOREVER_REL.rel_value_us)
        s2 = _ ("<unknown time>");
      else
        s2 = GNUNET_STRINGS_relative_time_to_string (info->value.download
                                                     .specifics.progress
                                                     .block_download_duration,
                                                     GNUNET_YES);
      t = GNUNET_STRINGS_byte_size_fancy (
        info->value.download.completed * 1000LL
        / (info->value.download.duration.rel_value_us + 1));
      fprintf (
        stdout,
        _ (
          "Downloading `%s' at %llu/%llu (%s remaining, %s/s). Block took %s to download\n"),
        info->value.download.filename,
        (unsigned long long) info->value.download.completed,
        (unsigned long long) info->value.download.size,
        s,
        t,
        s2);
      GNUNET_free (s);
      GNUNET_free (t);
    }
    else
    {
      display_bar (info->value.download.completed,
                   info->value.download.size,
                   60);
    }
    break;

  case GNUNET_FS_STATUS_DOWNLOAD_ERROR:
    if (0 != isatty (1))
      fprintf (stdout, "\n");
    fprintf (stderr,
             _ ("Error downloading: %s.\n"),
             info->value.download.specifics.error.message);
    GNUNET_SCHEDULER_shutdown ();
    break;

  case GNUNET_FS_STATUS_DOWNLOAD_COMPLETED:
    s = GNUNET_STRINGS_byte_size_fancy (
      info->value.download.completed * 1000
      / (info->value.download.duration.rel_value_us + 1));
    if (0 != isatty (1))
      fprintf (stdout, "\n");
    fprintf (stdout,
             _ ("Downloading `%s' done (%s/s).\n"),
             info->value.download.filename,
             s);
    GNUNET_free (s);
    if (info->value.download.dc == dc)
      GNUNET_SCHEDULER_shutdown ();
    break;

  case GNUNET_FS_STATUS_DOWNLOAD_STOPPED:
    if (info->value.download.dc == dc)
      GNUNET_SCHEDULER_add_now (&cleanup_task, NULL);
    break;

  case GNUNET_FS_STATUS_DOWNLOAD_ACTIVE:
  case GNUNET_FS_STATUS_DOWNLOAD_INACTIVE:
    break;

  default:
    fprintf (stderr, _ ("Unexpected status: %d\n"), info->status);
    break;
  }
  return NULL;
}


/**
 * Main function that will be run by the scheduler.
 *
 * @param cls closure
 * @param args remaining command-line arguments
 * @param cfgfile name of the configuration file used (for saving, can be NULL!)
 * @param c configuration
 */
static void
run (void *cls,
     char *const *args,
     const char *cfgfile,
     const struct GNUNET_CONFIGURATION_Handle *c)
{
  struct GNUNET_FS_Uri *uri;
  char *emsg;
  enum GNUNET_FS_DownloadOptions options;

  if (NULL == args[0])
  {
    fprintf (stderr, "%s", _ ("You need to specify a URI argument.\n"));
    return;
  }
  uri = GNUNET_FS_uri_parse (args[0], &emsg);
  if (NULL == uri)
  {
    fprintf (stderr, _ ("Failed to parse URI: %s\n"), emsg);
    GNUNET_free (emsg);
    ret = 1;
    return;
  }
  if ((! GNUNET_FS_uri_test_chk (uri)) && (! GNUNET_FS_uri_test_loc (uri)))
  {
    fprintf (stderr, "%s", _ ("Only CHK or LOC URIs supported.\n"));
    ret = 1;
    GNUNET_FS_uri_destroy (uri);
    return;
  }
  if (NULL == filename)
  {
    fprintf (stderr, "%s", _ ("Target filename must be specified.\n"));
    ret = 1;
    GNUNET_FS_uri_destroy (uri);
    return;
  }
  cfg = c;
  ctx = GNUNET_FS_start (cfg,
                         "gnunet-download",
                         &progress_cb,
                         NULL,
                         GNUNET_FS_FLAGS_NONE,
                         GNUNET_FS_OPTIONS_DOWNLOAD_PARALLELISM,
                         parallelism,
                         GNUNET_FS_OPTIONS_REQUEST_PARALLELISM,
                         request_parallelism,
                         GNUNET_FS_OPTIONS_END);
  if (NULL == ctx)
  {
    fprintf (stderr, _ ("Could not initialize `%s' subsystem.\n"), "FS");
    GNUNET_FS_uri_destroy (uri);
    ret = 1;
    return;
  }
  options = GNUNET_FS_DOWNLOAD_OPTION_NONE;
  if (do_recursive)
    options |= GNUNET_FS_DOWNLOAD_OPTION_RECURSIVE;
  if (local_only)
    options |= GNUNET_FS_DOWNLOAD_OPTION_LOOPBACK_ONLY;
  dc = GNUNET_FS_download_start (ctx,
                                 uri,
                                 NULL,
                                 filename,
                                 NULL,
                                 0,
                                 GNUNET_FS_uri_chk_get_file_size (uri),
                                 anonymity,
                                 options,
                                 NULL,
                                 NULL);
  GNUNET_FS_uri_destroy (uri);
  if (dc == NULL)
  {
    GNUNET_FS_stop (ctx);
    ctx = NULL;
    return;
  }
  GNUNET_SCHEDULER_add_shutdown (&shutdown_task, NULL);
}


/**
 * The main function to download GNUnet.
 *
 * @param argc number of arguments from the command line
 * @param argv command line arguments
 * @return 0 ok, 1 on error
 */
int
main (int argc, char *const *argv)
{
  struct GNUNET_GETOPT_CommandLineOption options[] =
  { GNUNET_GETOPT_option_uint ('a',
                               "anonymity",
                               "LEVEL",
                               gettext_noop (
                                 "set the desired LEVEL of receiver-anonymity"),
                               &anonymity),

    GNUNET_GETOPT_option_flag (
      'D',
      "delete-incomplete",
      gettext_noop ("delete incomplete downloads (when aborted with CTRL-C)"),
      &delete_incomplete),

    GNUNET_GETOPT_option_flag (
      'n',
      "no-network",
      gettext_noop ("only search the local peer (no P2P network search)"),
      &local_only),
    GNUNET_GETOPT_option_string ('o',
                                 "output",
                                 "FILENAME",
                                 gettext_noop ("write the file to FILENAME"),
                                 &filename),
    GNUNET_GETOPT_option_uint (
      'p',
      "parallelism",
      "DOWNLOADS",
      gettext_noop (
        "set the maximum number of parallel downloads that is allowed"),
      &parallelism),
    GNUNET_GETOPT_option_uint (
      'r',
      "request-parallelism",
      "REQUESTS",
      gettext_noop (
        "set the maximum number of parallel requests for blocks that is allowed"),
      &request_parallelism),
    GNUNET_GETOPT_option_flag ('R',
                               "recursive",
                               gettext_noop (
                                 "download a GNUnet directory recursively"),
                               &do_recursive),
    GNUNET_GETOPT_option_increment_uint (
      'V',
      "verbose",
      gettext_noop ("be verbose (print progress information)"),
      &verbose),
    GNUNET_GETOPT_OPTION_END };

  if (GNUNET_OK != GNUNET_STRINGS_get_utf8_args (argc, argv, &argc, &argv))
    return 2;

  ret =
    (GNUNET_OK ==
     GNUNET_PROGRAM_run (
       argc,
       argv,
       "gnunet-download [OPTIONS] URI",
       gettext_noop (
         "Download files from GNUnet using a GNUnet CHK or LOC URI (gnunet://fs/chk/...)"),
       options,
       &run,
       NULL))
    ? ret
    : 1;
  GNUNET_free ((void *) argv);
  return ret;
}


/* end of gnunet-download.c */