#include <glob.h>
#include <iostream>

#include "../FieldLists.h"
#include "HistoryFileWriter.h"


/* This program creates history/Index.xml.  This is what gets loaded by
 * ServerList so we know which instances of the server are responsible for
 * which data files.
 *
 * Currently this is very simple and it helps me set up my test environment.
 * Ideally this will evolve into the final version which automatically updates
 * whenever we get a new data file or a server goes out of commission.
 */

static int64_t getIndex(bool first, HistoryFileReader &reader)
{
  int64_t position;
  if (first)
    position = reader.findFirst(0);
  else
    position = reader.findLast(0x7fffffffffffffff);
  if (position == HistoryFileReader::INVALID)
    return 0;
  Record::Ref record;
  reader.readForward(position, record);
  if (!record)
    return 0;
  bool success;
  int64_t id;
  record->lookUpValue(MainFields::id).getInt(success, id);
  if (success)
    return id;
  else
    return 0;
}

struct ServerInfo
{
  std::string hostName;
  std::string port;
};

static ServerInfo getNextServer()
{
  return { "joey-mousepad", "7797" };
}

static std::string removeDir(std::string const &path)
{
  return *explode("/", path).rbegin();
}

XmlNode makeIndex(std::string const &filePattern)
{
  XmlNode result;
  result.name = "INDEX";
  XmlNode &serverList = result["CURRENT"];
  serverList.properties["version_number"] = ntoa(time(NULL));
  std::vector< std::string > fileList;
  glob_t results;
  int error = glob(filePattern.c_str(),
		   GLOB_NOSORT | GLOB_TILDE | GLOB_NOMAGIC, NULL, &results);
  if (!error)
    for (char **current = results.gl_pathv; *current; current++)
      fileList.push_back(*current);
  globfree(&results);
  for (std::string const &fileName : fileList)
  {
    HistoryFileReader reader(fileName);
    if (!reader.isGood())
    {
      std::cerr<<"Warning:  "<<reader.getErrorMessage()<<std::endl;
      continue;
    }
    int64_t start = getIndex(true, reader);
    if (start <= 0)
      continue;
    int64_t end = getIndex(false, reader);
    if (end <= 0)
      continue;
    ServerInfo serverInfo = getNextServer();
    XmlNode &serverXml = serverList[-1];
    serverXml.name = "SERVER";
    serverXml.properties["start"] = ntoa(start);
    serverXml.properties["end"] = ntoa(end + 1);
    serverXml.properties["host_name"] = serverInfo.hostName;
    serverXml.properties["port"] = serverInfo.port;
    serverXml.properties["file_name"] = removeDir(fileName);
  }
  return result;
}

void saveIndex(XmlNode const &xml, std::string const &fileName)
{
  std::string const body = xml.asString();
  std::ofstream file(fileName.c_str(),
		     std::ios_base::out | std::ios_base::trunc);
  file<<body<<std::endl;
  if (!file)
  {
    perror("saveIndex()");
    exit(1);
  }
}

int main(int, char **)
{
  saveIndex(makeIndex("history/*.history"), "history/Index.xml");
}
/* Here is a sample file created by this program just now:
 * <INDEX><CURRENT version_number="1548886972"><SERVER end="22743602605" file_name="1548416647.history" host_name="joey-mousepad" port="7797" start="22735630088" /><SERVER end="22751837172" file_name="1548675842.history" host_name="joey-mousepad" port="7797" start="22743602605" /><SERVER end="22759983167" file_name="1548762242.history" host_name="joey-mousepad" port="7797" start="22751837172" /></CURRENT></INDEX>
 *
 * Here are the corresponding outputs found in the log file when I ran
 * ./history_server -f ../../../live_server/config_common.txt
 * {Wed Jan 30 14:23:49 2019} 0 HistoryDirectory.C 108 HistoryDirectory {loading history file} fileId 1525762307537872549 fileName history/1548416647.history xml {{end 22743602605} {file_name 1548416647.history} {host_name joey-mousepad} {port 7797} {start 22735630088}}
 * {Wed Jan 30 14:23:49 2019} 0 HistoryDirectory.C 108 HistoryDirectory {loading history file} fileId 1526297334097225287 fileName history/1548675842.history xml {{end 22751837172} {file_name 1548675842.history} {host_name joey-mousepad} {port 7797} {start 22743602605}}
 * {Wed Jan 30 14:23:49 2019} 0 HistoryDirectory.C 108 HistoryDirectory {loading history file} fileId 1526849946534038603 fileName history/1548762242.history xml {{end 22759983167} {file_name 1548762242.history} {host_name joey-mousepad} {port 7797} {start 22751837172}}
 */