/*
  Copyright (C) 2005-2019 Marius L. Jøhndal

  This library 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.

  This library 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 library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

*/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif /* HAVE_CONFIG_H */

#define _GNU_SOURCE
#include <getopt.h>
#include <glib.h>
#include <glib/gprintf.h>
#include <glib/gstdio.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <libxml/parser.h>
#ifdef ENABLE_ID3LIB
#include <id3.h>
#endif /* ENABLE_ID3LIB */
#include "configuration.h"
#include "channel.h"

enum op {
  OP_UPDATE,
  OP_CATCHUP,
  OP_LIST
};

static int _process_channel(const gchar *channel_directory, GKeyFile *kf, const char *identifier,
                            enum op op, struct channel_configuration *defaults,
                            enclosure_filter *filter);
static void version(void);
static GKeyFile *_configuration_file_open(const gchar *rcfile);
static void _configuration_file_close(GKeyFile *kf);
#ifdef ENABLE_ID3LIB
static int _id3_set(const gchar *filename, int clear, const gchar *lead_artist,
                    const gchar *content_group, const gchar *title,
                    const gchar *album, const gchar *content_type, const gchar *year,
                    const gchar *comment);
static int _id3_check_and_set(const gchar *filename,
                              const struct channel_configuration *cfg);
#endif /* ENABLE_ID3LIB */
static int playlist_add(const gchar *playlist_file,
                        const gchar *media_file);

static gboolean verbose = FALSE;
static gboolean quiet = FALSE;
static gboolean first_only = FALSE;
static gboolean resume = FALSE;
static gboolean debug = FALSE;
static gboolean show_progress_bar = FALSE;
static gboolean show_version = FALSE;
static gboolean show_debug_info = FALSE;
static gboolean new_only = FALSE;
static gboolean list = FALSE;
static gboolean catchup = FALSE;
static gchar *rcfile = NULL;
static gchar *filter_regex = NULL;

int main(int argc, char **argv)
{
  enum op op = OP_UPDATE;
  int i;
  int ret = 0;
  gchar **groups;
  gchar *channeldir;
  GKeyFile *kf;
  struct channel_configuration *defaults;
  enclosure_filter *filter = NULL;
  GError *error = NULL;
  GOptionContext *context;

  static GOptionEntry options[] =
  {
    {"catchup",      'c', 0, G_OPTION_ARG_NONE,     &catchup,           "catch up with channels and exit"},
    {"list",         'l', 0, G_OPTION_ARG_NONE,     &list,              "list available enclosures that have not yet been downloaded and exit"},
    {"version",      'V', 0, G_OPTION_ARG_NONE,     &show_version,      "print version and exit"},

    {"resume",       'r', 0, G_OPTION_ARG_NONE,     &resume,            "resume aborted downloads"},
    {"rcfile",       'C', 0, G_OPTION_ARG_FILENAME, &rcfile,            "override the default configuration file name"},

    {"debug",        'd', 0, G_OPTION_ARG_NONE,     &show_debug_info,   "print connection debug information"},
    {"verbose",      'v', 0, G_OPTION_ARG_NONE,     &verbose,           "print detailed progress information"},
    {"progress-bar", 'p', 0, G_OPTION_ARG_NONE,     &show_progress_bar, "print progress bar"},

    {"new-only",     'n', 0, G_OPTION_ARG_NONE,     &new_only,          "only process new channels"},
    {"quiet",        'q', 0, G_OPTION_ARG_NONE,     &quiet,             "only print error messages"},
    {"first-only",   '1', 0, G_OPTION_ARG_NONE,     &first_only,        "only process the most recent item from each channel"},
    {"filter",       'f', 0, G_OPTION_ARG_STRING,   &filter_regex,      "only process items whose enclosure names match a regular expression"},

    { NULL }
  };

  context = g_option_context_new("CHANNELS");
  g_option_context_add_main_entries(context, options, NULL);

  if (!g_option_context_parse(context, &argc, &argv, &error)) {
    g_print("option parsing failed: %s\n", error->message);
    exit(1);
  }

  /* Do some additional sanity checking of options. */
  if ((verbose && quiet) || (show_progress_bar && quiet)) {
    g_print("option parsing failed: options are incompatible.\n");
    exit(1);
  }

  if ((catchup && list) || (catchup && show_version) || (list && show_version)) {
    g_print("option parsing failed: --catchup, --list and --version options are incompatible.\n");
    exit(1);
  }

  /* Decide on the action to take */
  if (show_version) {
    version();
    exit(0);
  }

  if (catchup)
    op = OP_CATCHUP;

  if (list)
    op = OP_LIST;

  if (filter_regex) {
    filter = enclosure_filter_new(filter_regex, FALSE);
    g_free(filter_regex);
  }

  if (verbose && new_only)
    g_print("Fetching new channels only...\n");

  LIBXML_TEST_VERSION;

  /* Build the channel directory path and ensure that it exists. */
  channeldir = g_build_filename(g_get_home_dir(), ".castget", NULL);

  if (!g_file_test(channeldir, G_FILE_TEST_IS_DIR)) {
    if (g_mkdir(channeldir, 0755) < 0) {
      perror("Error creating channel directory");
      return 1;
    }
  }

  /* Try opening configuration file. */
  if (!rcfile)
    /* Supply default path name. */
    rcfile = g_build_filename(g_get_home_dir(), ".castgetrc", NULL);

  kf = _configuration_file_open(rcfile);

  if (kf) {
    /* Read defaults. */
    if (g_key_file_has_group(kf, "*")) {
      /* Verify the keys in the global configuration. */
      if (channel_configuration_verify_keys(kf, "*") < 0)
        return -1;

      defaults = channel_configuration_new(kf, "*", NULL);
    } else
      defaults = NULL;

    /* Perform actions. */
    if (optind < argc) {
      while (optind < argc)
        _process_channel(channeldir, kf, argv[optind++], op, defaults,
                         filter);
    } else {
      groups = g_key_file_get_groups(kf, NULL);

      for (i = 0; groups[i]; i++)
        if (strcmp(groups[i], "*"))
          _process_channel(channeldir, kf, groups[i], op, defaults,
                           filter);

      g_strfreev(groups);
    }

    /* Clean up defaults. */
    if (defaults)
      channel_configuration_free(defaults);
  } else
    ret = 1;

  /* Clean-up. */
  g_free(channeldir);

  if (filter)
    enclosure_filter_free(filter);

  g_free(rcfile);

  if (kf)
    _configuration_file_close(kf);

  xmlCleanupParser();

  return ret;
}

static void version(void)
{
  g_printf("%s %s", PACKAGE, VERSION);
#ifdef ENABLE_ID3LIB
  g_printf(" with ID3 tag support\n");
#else
  g_printf("\n");
#endif

  g_printf("Copyright (C) 2005-2019 Marius L. Jøhndal <mariuslj at ifi.uio.no>\n");
}

static void _print_item_update(const enclosure *enclosure, const gchar *filename)
{
  if (enclosure->length > 0) {
    gchar *size = g_format_size(enclosure->length);
    g_printf(" * %s (%s)\n", enclosure->url, size);
    g_free(size);
  } else
    g_printf(" * %s (unknown size)\n", filename);
}

static void update_callback(void *user_data, channel_action action,
                            channel_info *channel_info, enclosure *enclosure,
                            const gchar *filename)
{
  struct channel_configuration *c = (struct channel_configuration *)user_data;

  switch (action) {
  case CCA_RSS_DOWNLOAD_START:
    if (!quiet)
      g_printf("Updating channel %s...\n", c->identifier);
    break;

  case CCA_RSS_DOWNLOAD_END:
    break;

  case CCA_ENCLOSURE_DOWNLOAD_START:
    g_assert(channel_info);
    g_assert(enclosure);

    if (verbose)
      _print_item_update(enclosure, filename);

    break;

  case CCA_ENCLOSURE_DOWNLOAD_END:
    g_assert(channel_info);
    g_assert(enclosure);
    g_assert(filename);

    /* Set media tags. */
    if (enclosure->type && (!strcmp(enclosure->type, "audio/mpeg") || !strcmp(enclosure->type, "audio/mp3"))) {
#ifdef ENABLE_ID3LIB
      if (_id3_check_and_set(filename, c))
        fprintf(stderr, "Error setting ID3 tag for file %s.\n", filename);
#endif /* ENABLE_ID3LIB */
    }

    /* Update playlist. */
    if (c->playlist) {
      playlist_add(c->playlist, filename);

      if (verbose)
        printf(" * Added downloaded enclosure %s to playlist %s.\n",
               filename, c->playlist);
    }
    break;
  }
}

static void catchup_callback(void *user_data, channel_action action, channel_info *channel_info,
                             enclosure *enclosure, const gchar *filename)
{
  struct channel_configuration *c = (struct channel_configuration *)user_data;

  switch (action) {
  case CCA_RSS_DOWNLOAD_START:
    if (!quiet)
      g_printf("Catching up with channel %s...\n", c->identifier);
    break;

  case CCA_RSS_DOWNLOAD_END:
    break;

  case CCA_ENCLOSURE_DOWNLOAD_START:
    g_assert(channel_info);
    g_assert(enclosure);

    if (verbose)
      _print_item_update(enclosure, filename);

    break;

  case CCA_ENCLOSURE_DOWNLOAD_END:
    break;
  }
}

static void list_callback(void *user_data, channel_action action, channel_info *channel_info,
                          enclosure *enclosure, const gchar *filename)
{
  struct channel_configuration *c = (struct channel_configuration *)user_data;

  switch (action) {
  case CCA_RSS_DOWNLOAD_START:
    g_printf("Listing channel %s...\n", c->identifier);
    break;

  case CCA_RSS_DOWNLOAD_END:
    break;

  case CCA_ENCLOSURE_DOWNLOAD_START:
    g_assert(channel_info);
    g_assert(enclosure);

    if (verbose)
      _print_item_update(enclosure, filename);

    break;

  case CCA_ENCLOSURE_DOWNLOAD_END:
    break;
  }
}

static int _process_channel(const gchar *channel_directory, GKeyFile *kf, const char *identifier,
                            enum op op, struct channel_configuration *defaults,
                            enclosure_filter *filter)
{
  channel *c;
  gchar *channel_filename, *channel_file;
  struct channel_configuration *channel_configuration;
  enclosure_filter *per_channel_filter = NULL;

  /* Check channel identifier and read channel configuration. */
  if (!g_key_file_has_group(kf, identifier)) {
    fprintf(stderr, "Unknown channel identifier %s.\n", identifier);

    return -1;
  }

  /* Verify the keys in the channel configuration. */
  if (channel_configuration_verify_keys(kf, identifier) < 0)
    return -1;

  channel_configuration = channel_configuration_new(kf, identifier, defaults);

  /* Check that mandatory keys were set. */
  if (!channel_configuration->url) {
    fprintf(stderr, "No feed URL set for channel %s.\n", identifier);

    channel_configuration_free(channel_configuration);
    return -1;
  }

  if (!channel_configuration->spool_directory) {
    fprintf(stderr, "No spool directory set for channel %s.\n", identifier);

    channel_configuration_free(channel_configuration);
    return -1;
  }

  /* Construct channel file name. */
  channel_filename = g_strjoin(".", identifier, "xml", NULL);
  channel_file = g_build_filename(channel_directory, channel_filename, NULL);
  g_free(channel_filename);

  if (new_only && access(channel_file, F_OK) == 0) {
    /* If we are only fetching new channels, skip the channel if there is
       already a channel file present. */

    channel_configuration_free(channel_configuration);
    return 0;
  }

  c = channel_new(channel_configuration->url, channel_file,
                  channel_configuration->spool_directory,
                  channel_configuration->filename_pattern,
                  resume);
  g_free(channel_file);

  if (!c) {
    fprintf(stderr, "Error parsing channel file for channel %s.\n", identifier);

    channel_configuration_free(channel_configuration);
    return -1;
  }

  /* Set up per-channel filter unless overridden on the command
     line. */
  if (!filter && channel_configuration->regex_filter) {
    per_channel_filter =
      enclosure_filter_new(channel_configuration->regex_filter, FALSE);

    filter = per_channel_filter;
  }

  switch (op) {
  case OP_UPDATE:
    channel_update(c, channel_configuration, update_callback, 0, 0,
                   first_only, resume, filter, debug, show_progress_bar);
    break;

  case OP_CATCHUP:
    channel_update(c, channel_configuration, catchup_callback, 1, 0,
                   first_only, 0, filter, debug, show_progress_bar);
    break;

  case OP_LIST:
    channel_update(c, channel_configuration, list_callback, 1, 1, first_only,
                   0, filter, debug, show_progress_bar);
    break;
  }

  /* Clean-up. */
  if (per_channel_filter)
    enclosure_filter_free(per_channel_filter);

  channel_free(c);
  channel_configuration_free(channel_configuration);

  return 0;
}

static GKeyFile *_configuration_file_open(const gchar *rcfile)
{
  GKeyFile *kf;
  GError *error = NULL;

  kf = g_key_file_new();

  if (!g_key_file_load_from_file(kf, rcfile, G_KEY_FILE_NONE, &error)) {
    fprintf(stderr, "Error reading configuration file %s: %s.\n", rcfile, error->message);
    g_error_free(error);
    g_key_file_free(kf);
    kf = NULL;
  }

  return kf;
}

static void _configuration_file_close(GKeyFile *kf)
{
  g_key_file_free(kf);
}

#ifdef ENABLE_ID3LIB
static int _id3_find_and_set_frame(ID3Tag *tag, ID3_FrameID id, const char *value)
{
  ID3Frame *frame;
  ID3Field *field;

  /* Remove existing tag to avoid issues with trashed frames. */
  while ((frame = ID3Tag_FindFrameWithID(tag, id)))
    ID3Tag_RemoveFrame(tag, frame);

  if (value && strlen(value) > 0) {
    frame = ID3Frame_NewID(id);
    g_assert(frame);

    ID3Tag_AttachFrame(tag, frame);

    field = ID3Frame_GetField(frame, ID3FN_TEXT);

    if (field)
      ID3Field_SetASCII(field, value); //TODO: UTF8
    else
      return 1;
  }

  return 0;
}

static int _id3_set(const gchar *filename, int clear, const gchar *lead_artist,
                    const gchar *content_group, const gchar *title, const gchar *album,
                    const gchar *content_type, const gchar *year, const gchar *comment)
{
  int errors = 0;
  ID3Tag *tag;

  tag = ID3Tag_New();

  if (!tag)
    return 1;

  ID3Tag_Link(tag, filename);

  if (clear)
    ID3Tag_Clear(tag); // TODO

  if (lead_artist) {
    errors += _id3_find_and_set_frame(tag, ID3FID_LEADARTIST, lead_artist);

    if (verbose)
      printf(" * Set ID3 tag lead artist to %s.\n", lead_artist);
  }

  if (content_group) {
    errors += _id3_find_and_set_frame(tag, ID3FID_CONTENTGROUP, content_group);

    if (verbose)
      printf(" * Set ID3 tag content group to %s.\n", content_group);
  }

  if (title) {
    errors += _id3_find_and_set_frame(tag, ID3FID_TITLE, title);

    if (verbose)
      printf(" * Set ID3 tag title to %s.\n", title);
  }

  if (album) {
    errors += _id3_find_and_set_frame(tag, ID3FID_ALBUM, album);

    if (verbose)
      printf(" * Set ID3 tag album to %s.\n", album);
  }

  if (content_type) {
    errors += _id3_find_and_set_frame(tag, ID3FID_CONTENTTYPE, content_type);

    if (verbose)
      printf(" * Set ID3 tag content type to %s.\n", content_type);
  }

  if (year) {
    errors += _id3_find_and_set_frame(tag, ID3FID_YEAR, year);

    if (verbose)
      printf(" * Set ID3 title year to %s.\n", year);
  }

  if (comment) {
    errors += _id3_find_and_set_frame(tag, ID3FID_COMMENT, comment);

    if (verbose)
      printf(" * Set ID3 tag comment to %s.\n", comment);
  }

  if (!errors)
    ID3Tag_Update(tag);

  ID3Tag_Delete(tag);

  return errors;
}

static int _id3_check_and_set(const gchar *filename,
                              const struct channel_configuration *cfg)
{
  if (cfg->id3_lead_artist || cfg->id3_content_group || cfg->id3_title ||
      cfg->id3_album || cfg->id3_content_type || cfg->id3_year || cfg->id3_comment)
    return _id3_set(filename, 0, cfg->id3_lead_artist, cfg->id3_content_group,
                    cfg->id3_title, cfg->id3_album, cfg->id3_content_type,
                    cfg->id3_year, cfg->id3_comment);
  else
    return 0;
}

#endif /* ENABLE_ID3LIB */

static int playlist_add(const gchar *playlist_file,
                        const gchar *media_file)
{
  FILE *f;

  f = fopen(playlist_file, "a");

  if (!f) {
    fprintf(stderr, "Error opening playlist file %s: %s.\n",
            playlist_file, strerror(errno));
    return -1;
  }

  fprintf(f, "%s\n", media_file);
  fclose(f);
  return 0;
}