#include <cerrno>
#include <iostream>
#include "globals.hh"
#include "legacy.hh"
#include "profiles.hh"
#include "shared.hh"
#include "store-api.hh"

using namespace nix;

std::string deleteOlderThan;
bool dryRun = false;

/* If `-d' was specified, remove all old generations of all profiles.
 * Of course, this makes rollbacks to before this point in time
 * impossible. */

void removeOldGenerations(std::string dir) {
  if (access(dir.c_str(), R_OK) != 0) return;

  bool canWrite = access(dir.c_str(), W_OK) == 0;

  for (auto& i : readDirectory(dir)) {
    checkInterrupt();

    auto path = dir + "/" + i.name;
    auto type = i.type == DT_UNKNOWN ? getFileType(path) : i.type;

    if (type == DT_LNK && canWrite) {
      std::string link;
      try {
        link = readLink(path);
      } catch (SysError& e) {
        if (e.errNo == ENOENT) continue;
      }
      if (link.find("link") != string::npos) {
        printInfo(format("removing old generations of profile %1%") % path);
        if (deleteOlderThan != "")
          deleteGenerationsOlderThan(path, deleteOlderThan, dryRun);
        else
          deleteOldGenerations(path, dryRun);
      }
    } else if (type == DT_DIR) {
      removeOldGenerations(path);
    }
  }
}

static int _main(int argc, char** argv) {
  {
    bool removeOld = false;

    GCOptions options;

    parseCmdLine(
        argc, argv, [&](Strings::iterator& arg, const Strings::iterator& end) {
          if (*arg == "--help")
            showManPage("nix-collect-garbage");
          else if (*arg == "--version")
            printVersion("nix-collect-garbage");
          else if (*arg == "--delete-old" || *arg == "-d")
            removeOld = true;
          else if (*arg == "--delete-older-than") {
            removeOld = true;
            deleteOlderThan = getArg(*arg, arg, end);
          } else if (*arg == "--dry-run")
            dryRun = true;
          else if (*arg == "--max-freed") {
            long long maxFreed = getIntArg<long long>(*arg, arg, end, true);
            options.maxFreed = maxFreed >= 0 ? maxFreed : 0;
          } else
            return false;
          return true;
        });

    initPlugins();

    auto profilesDir = settings.nixStateDir + "/profiles";
    if (removeOld) removeOldGenerations(profilesDir);

    // Run the actual garbage collector.
    if (!dryRun) {
      auto store = openStore();
      options.action = GCOptions::gcDeleteDead;
      GCResults results;
      PrintFreed freed(true, results);
      store->collectGarbage(options, results);
    }

    return 0;
  }
}

static RegisterLegacyCommand s1("nix-collect-garbage", _main);