/// \file controller_updater.cpp
/// Contains all code for the controller updater.

#include "controller_updater.h"
#include "controller_connectors.h"
#include "controller_storage.h"
#include <fstream>  //for files
#include <iostream> //for stdio
#include <mist/auth.h>
#include <mist/config.h>
#include <mist/defines.h>
#include <mist/downloader.h>
#include <mist/http_parser.h>
#include <mist/timing.h>
#include <signal.h>   //for raise
#include <sys/stat.h> //for chmod
#include <time.h>     //for time
#include <unistd.h>   //for unlink

#define UPDATE_INTERVAL 3600
#ifndef SHARED_SECRET
#define SHARED_SECRET "empty"
#endif

static std::string readFile(std::string filename){
  std::ifstream file(filename.c_str());
  if (!file.good()){return "";}
  file.seekg(0, std::ios::end);
  unsigned int len = file.tellg();
  file.seekg(0, std::ios::beg);
  std::string out;
  out.reserve(len);
  unsigned int i = 0;
  while (file.good() && i++ < len){out += file.get();}
  file.close();
  return out;
}

static bool writeFile(std::string filename, std::string &contents){
  unlink(filename.c_str());
  std::ofstream file(filename.c_str(), std::ios_base::trunc | std::ios_base::out);
  if (!file.is_open()){return false;}
  file << contents;
  file.close();
  chmod(filename.c_str(), S_IRWXU | S_IRWXG);
  return true;
}

tthread::mutex updaterMutex;
uint8_t updatePerc = 0;
JSON::Value updates;
HTTP::Downloader DL;

namespace Controller{

  void updateThread(void *np){
    uint64_t updateChecker = Util::epoch() - UPDATE_INTERVAL;
    while (Controller::conf.is_active){
      if (Util::epoch() - updateChecker > UPDATE_INTERVAL || updatePerc){
        JSON::Value result = Controller::checkUpdateInfo();
        if (result.isMember("error")){
          FAIL_MSG("Error retrieving update information: %s",
                   result["error"].asStringRef().c_str());
        }
        {// Lock the mutex, update the updates object
          tthread::lock_guard<tthread::mutex> guard(updaterMutex);
          updates = result;
        }
        if (!result["uptodate"] && updatePerc){
          // loop through the available components, update them
          unsigned int needCount = result["needs_update"].size();
          if (needCount){
            jsonForEach(result["needs_update"], it){
              if (!Controller::conf.is_active){break;}
              updatePerc = ((it.num() * 99) / needCount) + 1;
              updateComponent(it->asStringRef(), result[it->asStringRef()].asStringRef());
            }
          }
          updatePerc = 0;
        }
        updateChecker = Util::epoch();
      }
      Util::sleep(3000);
    }
  }

  void insertUpdateInfo(JSON::Value &ret){
    tthread::lock_guard<tthread::mutex> guard(updaterMutex);
    ret = updates;
    if (updatePerc){ret["progress"] = (uint16_t)updatePerc;}
  }

  /// Downloads the latest details on updates
  JSON::Value checkUpdateInfo(){
    JSON::Value ret;
    if (strlen(SHARED_SECRET) < 8){
      Log("UPDR", "Self-compiled build. Updater disabled.");
      ret["uptodate"] = 1;
      ret["needs_update"].null();
      ret["release"] = "Self-compiled";
      ret["version"] = "Unknown";
      ret["date"] = "Now";
      return ret;
    }
    HTTP::Parser http;
    JSON::Value updrInfo;
    if (DL.get("http://releases.mistserver.org/getsums.php?verinfo=1&rel=" RELEASE "&pass=" SHARED_SECRET "&iid=" + instanceId) && DL.isOk()){
      updrInfo = JSON::fromString(DL.data());
    }else{
      Log("UPDR", "Error getting update info: "+DL.getStatusText());
      ret["error"] = "Error getting update info: "+DL.getStatusText();
      ret["uptodate"] = 1;
      return ret;
    }
    if (updrInfo){
      if (updrInfo.isMember("error")){
        Log("UPDR", updrInfo["error"].asStringRef());
        ret["error"] = updrInfo["error"];
        ret["uptodate"] = 1;
        return ret;
      }
      ret["release"] = RELEASE;
      if (updrInfo.isMember("version")){ret["version"] = updrInfo["version"];}
      if (updrInfo.isMember("date")){ret["date"] = updrInfo["date"];}
      ret["uptodate"] = 1;
      ret["needs_update"].null();

      // check if everything is up to date or not
      jsonForEach(updrInfo, it){
        if (it.key().substr(0, 4) != "Mist"){continue;}
        ret[it.key()] = *it;
        if (it->asString() != Secure::md5(readFile(Util::getMyPath() + it.key()))){
          ret["uptodate"] = 0;
          if (it.key().substr(0, 14) == "MistController"){
            ret["needs_update"].append(it.key());
          }else{
            ret["needs_update"].prepend(it.key());
          }
        }
      }
    }else{
      Log("UPDR", "Could not retrieve update information from releases server.");
      ret["error"] = "Could not retrieve update information from releases server.";
    }
    return ret;
  }

  /// Causes the updater thread to download an update, if available
  void checkUpdates(){updatePerc = 1;}// CheckUpdates

  /// Attempts to download an update for the listed component.
  /// \param component Filename of the component being checked.
  /// \param md5sum The MD5 sum of the latest version of this file.
  /// \param updrConn An connection to releases.mistserver.org to (re)use. Will be (re)opened if
  /// closed.
  void updateComponent(const std::string &component, const std::string &md5sum){
    Log("UPDR", "Updating " + component);
    if (!DL.get("http://releases.mistserver.org/getfile.php?rel=" RELEASE "&pass=" SHARED_SECRET "&file=" + component) || !DL.isOk() || !DL.data().size()){
      FAIL_MSG("Could not retrieve new version of %s, continuing without", component.c_str());
      return;
    }
    if (Secure::md5(DL.data()) != md5sum){
      FAIL_MSG("Checksum of %s incorrect, continuing without", component.c_str());
      return;
    }
    if (!writeFile(Util::getMyPath() + component, DL.data())){
      FAIL_MSG("Could not write updated version of %s, continuing without", component.c_str());
      return;
    }
    Controller::UpdateProtocol(component);
    if (component == "MistController"){
      restarting = true;
      raise(SIGINT); // trigger restart
    }
    Log("UPDR", "New version of " + component + " installed.");
  }
}