// Copyright (c) 2012 Facebook.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <algorithm>
#include <string>
#include <stdint.h>
#include "db/db_impl.h"
#include "db/filename.h"
#include "db/version_set.h"
#include "leveldb/db.h"
#include "leveldb/env.h"
#include "port/port.h"
#include "util/mutexlock.h"

namespace leveldb {

Status DBImpl::DisableFileDeletions() {
  MutexLock l(&mutex_);
  disable_delete_obsolete_files_ = true;
  Log(options_.info_log, "File Deletions Disabled");
  return Status::OK();
}

Status DBImpl::EnableFileDeletions() {
  MutexLock l(&mutex_);
  disable_delete_obsolete_files_ = false;
  Log(options_.info_log, "File Deletions Enabled");
  return Status::OK();
}

Status DBImpl::GetLiveFiles(std::vector<std::string>& ret,
                            uint64_t* manifest_file_size) {

  *manifest_file_size = 0;

  // flush all dirty data to disk.
  Status status =  Flush(FlushOptions());
  if (!status.ok()) {
    Log(options_.info_log, "Cannot Flush data %s\n",
        status.ToString().c_str());
    return status;
  }

  MutexLock l(&mutex_);

  // Make a set of all of the live *.sst files
  std::set<uint64_t> live;
  versions_->AddLiveFilesCurrentVersion(&live);

  ret.resize(live.size() + 2); //*.sst + CURRENT + MANIFEST

  // create names of the live files. The names are not absolute
  // paths, instead they are relative to dbname_;
  std::set<uint64_t>::iterator it = live.begin();
  for (unsigned int i = 0; i < live.size(); i++, it++) {
    ret[i] = TableFileName("", *it);
  }

  ret[live.size()] = CurrentFileName("");
  ret[live.size()+1] = DescriptorFileName("",
                                          versions_->ManifestFileNumber());

  // find length of manifest file while holding the mutex lock
  *manifest_file_size = versions_->ManifestFileSize();

  return Status::OK();
}

Status DBImpl::GetSortedWalFiles(VectorLogPtr& files) {
  // First get sorted files in archive dir, then append sorted files from main
  // dir to maintain sorted order

  //  list wal files in archive dir.
  Status s;
  std::string archivedir = ArchivalDirectory(dbname_);
  if (env_->FileExists(archivedir)) {
    s = AppendSortedWalsOfType(archivedir, files, kArchivedLogFile);
    if (!s.ok()) {
      return s;
    }
  }
  // list wal files in main db dir.
  s = AppendSortedWalsOfType(dbname_, files, kAliveLogFile);
  if (!s.ok()) {
    return s;
  }
  return s;
}

Status DBImpl::DeleteWalFiles(const VectorLogPtr& files) {
  Status s;
  std::string archivedir = ArchivalDirectory(dbname_);
  std::string files_not_deleted;
  for (const auto& wal : files) {
    /* Try deleting in archive dir. If fails, try deleting in main db dir.
     * This is efficient because all except for very few wal files will be in
     * archive. Checking for WalType is not much helpful because alive wal could
       be archived now.
     */
    if (!env_->DeleteFile(archivedir + "/" + wal->Filename()).ok() &&
        !env_->DeleteFile(dbname_ + "/" + wal->Filename()).ok()) {
      files_not_deleted.append(wal->Filename());
    }
  }
  if (!files_not_deleted.empty()) {
    return Status::IOError("Deleted all requested files except: " +
                           files_not_deleted);
  }
  return Status::OK();
}

}