/*
Copyright (©) 2003-2020 Teus Benschop.

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

This program 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 General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/


#include <tasks/logic.h>
#include <database/logs.h>
#include <filter/string.h>
#include <filter/url.h>
#include <filter/date.h>


// Folder where the tasks are stored.
string tasks_logic_folder ()
{
  return filter_url_create_root_path ("processes");
}


// Queue task $command to run later, with $parameters for that task.
void tasks_logic_queue (string command, vector <string> parameters)
{
  // The file on disk will contain the command on the first line,
  // and any parameters on the following lines, one parameters per line.
  vector <string> lines;
  lines.push_back (command);
  lines.insert (lines.end(), parameters.begin(), parameters.end());
  // The filename to write to contains seconds and microseconds.
  string seconds = convert_to_string (filter_date_seconds_since_epoch ());
  string time = seconds + filter_string_fill (convert_to_string (filter_date_numerical_microseconds ()), 8, '0');
  string file = filter_url_create_path (tasks_logic_folder (), time);
  // On Windows the microtime is not fine enough.
  // This leads to one task overwriting a previous one in case it is queued immediately after.
  // Deal with that problem here: Ensure the filename is unique.
  file = filter_url_unique_path (file);
  // Save it.
  command = filter_string_implode (lines, "\n");
  filter_url_file_put_contents (file, command);
}


// If $command and $parameters are queued as a task, the function returns true.
// Else it returns false.
// It looks for an exact match.
// Parameters left out are not checked.
bool tasks_logic_queued (string command, vector <string> parameters)
{
  // The lines to look for consist of the command followed by the parameters.
  vector <string> search (parameters);
  search.insert (search.begin (), command);
  // Go through all queued tasks.
  vector <string> files = filter_url_scandir (tasks_logic_folder ());
  for (auto & file : files) {
    // Read the task's contents.
    string contents = filter_url_file_get_contents (filter_url_create_path (tasks_logic_folder (), file));
    vector <string> lines = filter_string_explode (contents, '\n');
    if (lines.empty ()) return false;
    // Look for a match.
    bool match = true;
    for (size_t i = 0; i < search.size (); i++) {
      if (i < lines.size ()) {
        if (search [i] != lines[i]) match = false;
      } else {
        match = false;
      }
    }
    if (match) return true;
  }
  // No match found.
  return false;
}

