#include <kcpolydb.h>

#include <cstdio>
#include <cstdlib>

#include "util/histogram.h"
#include "util/random.h"
#include "util/testutil.h"

// Comma-separated list of operations to run in the specified order
//   Actual benchmarks:
//
//   fillseq       -- write N values in sequential key order in async mode
//   fillrandom    -- write N values in random key order in async mode
//   overwrite     -- overwrite N values in random key order in async mode
//   fillseqsync   -- write N/100 values in sequential key order in sync mode
//   fillrandsync  -- write N/100 values in random key order in sync mode
//   fillrand100K  -- write N/1000 100K values in random order in async mode
//   fillseq100K   -- write N/1000 100K values in seq order in async mode
//   readseq       -- read N times sequentially
//   readseq100K   -- read N/1000 100K values in sequential order in async mode
//   readrand100K  -- read N/1000 100K values in sequential order in async mode
//   readrandom    -- read N times in random order
static const char* FLAGS_benchmarks =
    "fillseq,"
    "fillseqsync,"
    "fillrandsync,"
    "fillrandom,"
    "overwrite,"
    "readrandom,"
    "readseq,"
    "fillrand100K,"
    "fillseq100K,"
    "readseq100K,"
    "readrand100K,";

// Number of key/values to place in database
static int FLAGS_num = 1000000;

// Number of read operations to do.  If negative, do FLAGS_num reads.
static int FLAGS_reads = -1;

// Size of each value
static int FLAGS_value_size = 100;

// Arrange to generate values that shrink to this fraction of
// their original size after compression
static double FLAGS_compression_ratio = 0.5;

// Print histogram of operation timings
static bool FLAGS_histogram = false;

// Cache size. Default 4 MB
static int FLAGS_cache_size = 4194304;

// Page size. Default 1 KB
static int FLAGS_page_size = 1024;

// If true, do not destroy the existing database.  If you set this
// flag and also specify a benchmark that wants a fresh database, that
// benchmark will fail.
static bool FLAGS_use_existing_db = false;

// Compression flag. If true, compression is on. If false, compression
// is off.
static bool FLAGS_compression = true;

// Use the db with the following name.
static const char* FLAGS_db = nullptr;

inline static void DBSynchronize(kyotocabinet::TreeDB* db_) {
  // Synchronize will flush writes to disk
  if (!db_->synchronize()) {
    std::fprintf(stderr, "synchronize error: %s\n", db_->error().name());
  }
}

namespace leveldb {

// Helper for quickly generating random data.
namespace {
class RandomGenerator {
 private:
  std::string data_;
  int pos_;

 public:
  RandomGenerator() {
    // We use a limited amount of data over and over again and ensure
    // that it is larger than the compression window (32KB), and also
    // large enough to serve all typical value sizes we want to write.
    Random rnd(301);
    std::string piece;
    while (data_.size() < 1048576) {
      // Add a short fragment that is as compressible as specified
      // by FLAGS_compression_ratio.
      test::CompressibleString(&rnd, FLAGS_compression_ratio, 100, &piece);
      data_.append(piece);
    }
    pos_ = 0;
  }

  Slice Generate(int len) {
    if (pos_ + len > data_.size()) {
      pos_ = 0;
      assert(len < data_.size());
    }
    pos_ += len;
    return Slice(data_.data() + pos_ - len, len);
  }
};

static Slice TrimSpace(Slice s) {
  int start = 0;
  while (start < s.size() && isspace(s[start])) {
    start++;
  }
  int limit = s.size();
  while (limit > start && isspace(s[limit - 1])) {
    limit--;
  }
  return Slice(s.data() + start, limit - start);
}

}  // namespace

class Benchmark {
 private:
  kyotocabinet::TreeDB* db_;
  int db_num_;
  int num_;
  int reads_;
  double start_;
  double last_op_finish_;
  int64_t bytes_;
  std::string message_;
  Histogram hist_;
  RandomGenerator gen_;
  Random rand_;
  kyotocabinet::LZOCompressor<kyotocabinet::LZO::RAW> comp_;

  // State kept for progress messages
  int done_;
  int next_report_;  // When to report next

  void PrintHeader() {
    const int kKeySize = 16;
    PrintEnvironment();
    std::fprintf(stdout, "Keys:       %d bytes each\n", kKeySize);
    std::fprintf(
        stdout, "Values:     %d bytes each (%d bytes after compression)\n",
        FLAGS_value_size,
        static_cast<int>(FLAGS_value_size * FLAGS_compression_ratio + 0.5));
    std::fprintf(stdout, "Entries:    %d\n", num_);
    std::fprintf(stdout, "RawSize:    %.1f MB (estimated)\n",
                 ((static_cast<int64_t>(kKeySize + FLAGS_value_size) * num_) /
                  1048576.0));
    std::fprintf(
        stdout, "FileSize:   %.1f MB (estimated)\n",
        (((kKeySize + FLAGS_value_size * FLAGS_compression_ratio) * num_) /
         1048576.0));
    PrintWarnings();
    std::fprintf(stdout, "------------------------------------------------\n");
  }

  void PrintWarnings() {
#if defined(__GNUC__) && !defined(__OPTIMIZE__)
    std::fprintf(
        stdout,
        "WARNING: Optimization is disabled: benchmarks unnecessarily slow\n");
#endif
#ifndef NDEBUG
    std::fprintf(
        stdout,
        "WARNING: Assertions are enabled; benchmarks unnecessarily slow\n");
#endif
  }

  void PrintEnvironment() {
    std::fprintf(
        stderr, "Kyoto Cabinet:    version %s, lib ver %d, lib rev %d\n",
        kyotocabinet::VERSION, kyotocabinet::LIBVER, kyotocabinet::LIBREV);

#if defined(__linux)
    time_t now = time(nullptr);
    std::fprintf(stderr, "Date:           %s",
                 ctime(&now));  // ctime() adds newline

    FILE* cpuinfo = std::fopen("/proc/cpuinfo", "r");
    if (cpuinfo != nullptr) {
      char line[1000];
      int num_cpus = 0;
      std::string cpu_type;
      std::string cache_size;
      while (fgets(line, sizeof(line), cpuinfo) != nullptr) {
        const char* sep = strchr(line, ':');
        if (sep == nullptr) {
          continue;
        }
        Slice key = TrimSpace(Slice(line, sep - 1 - line));
        Slice val = TrimSpace(Slice(sep + 1));
        if (key == "model name") {
          ++num_cpus;
          cpu_type = val.ToString();
        } else if (key == "cache size") {
          cache_size = val.ToString();
        }
      }
      std::fclose(cpuinfo);
      std::fprintf(stderr, "CPU:            %d * %s\n", num_cpus,
                   cpu_type.c_str());
      std::fprintf(stderr, "CPUCache:       %s\n", cache_size.c_str());
    }
#endif
  }

  void Start() {
    start_ = Env::Default()->NowMicros() * 1e-6;
    bytes_ = 0;
    message_.clear();
    last_op_finish_ = start_;
    hist_.Clear();
    done_ = 0;
    next_report_ = 100;
  }

  void FinishedSingleOp() {
    if (FLAGS_histogram) {
      double now = Env::Default()->NowMicros() * 1e-6;
      double micros = (now - last_op_finish_) * 1e6;
      hist_.Add(micros);
      if (micros > 20000) {
        std::fprintf(stderr, "long op: %.1f micros%30s\r", micros, "");
        std::fflush(stderr);
      }
      last_op_finish_ = now;
    }

    done_++;
    if (done_ >= next_report_) {
      if (next_report_ < 1000)
        next_report_ += 100;
      else if (next_report_ < 5000)
        next_report_ += 500;
      else if (next_report_ < 10000)
        next_report_ += 1000;
      else if (next_report_ < 50000)
        next_report_ += 5000;
      else if (next_report_ < 100000)
        next_report_ += 10000;
      else if (next_report_ < 500000)
        next_report_ += 50000;
      else
        next_report_ += 100000;
      std::fprintf(stderr, "... finished %d ops%30s\r", done_, "");
      std::fflush(stderr);
    }
  }

  void Stop(const Slice& name) {
    double finish = Env::Default()->NowMicros() * 1e-6;

    // Pretend at least one op was done in case we are running a benchmark
    // that does not call FinishedSingleOp().
    if (done_ < 1) done_ = 1;

    if (bytes_ > 0) {
      char rate[100];
      std::snprintf(rate, sizeof(rate), "%6.1f MB/s",
                    (bytes_ / 1048576.0) / (finish - start_));
      if (!message_.empty()) {
        message_ = std::string(rate) + " " + message_;
      } else {
        message_ = rate;
      }
    }

    std::fprintf(stdout, "%-12s : %11.3f micros/op;%s%s\n",
                 name.ToString().c_str(), (finish - start_) * 1e6 / done_,
                 (message_.empty() ? "" : " "), message_.c_str());
    if (FLAGS_histogram) {
      std::fprintf(stdout, "Microseconds per op:\n%s\n",
                   hist_.ToString().c_str());
    }
    std::fflush(stdout);
  }

 public:
  enum Order { SEQUENTIAL, RANDOM };
  enum DBState { FRESH, EXISTING };

  Benchmark()
      : db_(nullptr),
        num_(FLAGS_num),
        reads_(FLAGS_reads < 0 ? FLAGS_num : FLAGS_reads),
        bytes_(0),
        rand_(301) {
    std::vector<std::string> files;
    std::string test_dir;
    Env::Default()->GetTestDirectory(&test_dir);
    Env::Default()->GetChildren(test_dir.c_str(), &files);
    if (!FLAGS_use_existing_db) {
      for (int i = 0; i < files.size(); i++) {
        if (Slice(files[i]).starts_with("dbbench_polyDB")) {
          std::string file_name(test_dir);
          file_name += "/";
          file_name += files[i];
          Env::Default()->RemoveFile(file_name.c_str());
        }
      }
    }
  }

  ~Benchmark() {
    if (!db_->close()) {
      std::fprintf(stderr, "close error: %s\n", db_->error().name());
    }
  }

  void Run() {
    PrintHeader();
    Open(false);

    const char* benchmarks = FLAGS_benchmarks;
    while (benchmarks != nullptr) {
      const char* sep = strchr(benchmarks, ',');
      Slice name;
      if (sep == nullptr) {
        name = benchmarks;
        benchmarks = nullptr;
      } else {
        name = Slice(benchmarks, sep - benchmarks);
        benchmarks = sep + 1;
      }

      Start();

      bool known = true;
      bool write_sync = false;
      if (name == Slice("fillseq")) {
        Write(write_sync, SEQUENTIAL, FRESH, num_, FLAGS_value_size, 1);
        DBSynchronize(db_);
      } else if (name == Slice("fillrandom")) {
        Write(write_sync, RANDOM, FRESH, num_, FLAGS_value_size, 1);
        DBSynchronize(db_);
      } else if (name == Slice("overwrite")) {
        Write(write_sync, RANDOM, EXISTING, num_, FLAGS_value_size, 1);
        DBSynchronize(db_);
      } else if (name == Slice("fillrandsync")) {
        write_sync = true;
        Write(write_sync, RANDOM, FRESH, num_ / 100, FLAGS_value_size, 1);
        DBSynchronize(db_);
      } else if (name == Slice("fillseqsync")) {
        write_sync = true;
        Write(write_sync, SEQUENTIAL, FRESH, num_ / 100, FLAGS_value_size, 1);
        DBSynchronize(db_);
      } else if (name == Slice("fillrand100K")) {
        Write(write_sync, RANDOM, FRESH, num_ / 1000, 100 * 1000, 1);
        DBSynchronize(db_);
      } else if (name == Slice("fillseq100K")) {
        Write(write_sync, SEQUENTIAL, FRESH, num_ / 1000, 100 * 1000, 1);
        DBSynchronize(db_);
      } else if (name == Slice("readseq")) {
        ReadSequential();
      } else if (name == Slice("readrandom")) {
        ReadRandom();
      } else if (name == Slice("readrand100K")) {
        int n = reads_;
        reads_ /= 1000;
        ReadRandom();
        reads_ = n;
      } else if (name == Slice("readseq100K")) {
        int n = reads_;
        reads_ /= 1000;
        ReadSequential();
        reads_ = n;
      } else {
        known = false;
        if (name != Slice()) {  // No error message for empty name
          std::fprintf(stderr, "unknown benchmark '%s'\n",
                       name.ToString().c_str());
        }
      }
      if (known) {
        Stop(name);
      }
    }
  }

 private:
  void Open(bool sync) {
    assert(db_ == nullptr);

    // Initialize db_
    db_ = new kyotocabinet::TreeDB();
    char file_name[100];
    db_num_++;
    std::string test_dir;
    Env::Default()->GetTestDirectory(&test_dir);
    std::snprintf(file_name, sizeof(file_name), "%s/dbbench_polyDB-%d.kct",
                  test_dir.c_str(), db_num_);

    // Create tuning options and open the database
    int open_options =
        kyotocabinet::PolyDB::OWRITER | kyotocabinet::PolyDB::OCREATE;
    int tune_options =
        kyotocabinet::TreeDB::TSMALL | kyotocabinet::TreeDB::TLINEAR;
    if (FLAGS_compression) {
      tune_options |= kyotocabinet::TreeDB::TCOMPRESS;
      db_->tune_compressor(&comp_);
    }
    db_->tune_options(tune_options);
    db_->tune_page_cache(FLAGS_cache_size);
    db_->tune_page(FLAGS_page_size);
    db_->tune_map(256LL << 20);
    if (sync) {
      open_options |= kyotocabinet::PolyDB::OAUTOSYNC;
    }
    if (!db_->open(file_name, open_options)) {
      std::fprintf(stderr, "open error: %s\n", db_->error().name());
    }
  }

  void Write(bool sync, Order order, DBState state, int num_entries,
             int value_size, int entries_per_batch) {
    // Create new database if state == FRESH
    if (state == FRESH) {
      if (FLAGS_use_existing_db) {
        message_ = "skipping (--use_existing_db is true)";
        return;
      }
      delete db_;
      db_ = nullptr;
      Open(sync);
      Start();  // Do not count time taken to destroy/open
    }

    if (num_entries != num_) {
      char msg[100];
      std::snprintf(msg, sizeof(msg), "(%d ops)", num_entries);
      message_ = msg;
    }

    // Write to database
    for (int i = 0; i < num_entries; i++) {
      const int k = (order == SEQUENTIAL) ? i : (rand_.Next() % num_entries);
      char key[100];
      std::snprintf(key, sizeof(key), "%016d", k);
      bytes_ += value_size + strlen(key);
      std::string cpp_key = key;
      if (!db_->set(cpp_key, gen_.Generate(value_size).ToString())) {
        std::fprintf(stderr, "set error: %s\n", db_->error().name());
      }
      FinishedSingleOp();
    }
  }

  void ReadSequential() {
    kyotocabinet::DB::Cursor* cur = db_->cursor();
    cur->jump();
    std::string ckey, cvalue;
    while (cur->get(&ckey, &cvalue, true)) {
      bytes_ += ckey.size() + cvalue.size();
      FinishedSingleOp();
    }
    delete cur;
  }

  void ReadRandom() {
    std::string value;
    for (int i = 0; i < reads_; i++) {
      char key[100];
      const int k = rand_.Next() % reads_;
      std::snprintf(key, sizeof(key), "%016d", k);
      db_->get(key, &value);
      FinishedSingleOp();
    }
  }
};

}  // namespace leveldb

int main(int argc, char** argv) {
  std::string default_db_path;
  for (int i = 1; i < argc; i++) {
    double d;
    int n;
    char junk;
    if (leveldb::Slice(argv[i]).starts_with("--benchmarks=")) {
      FLAGS_benchmarks = argv[i] + strlen("--benchmarks=");
    } else if (sscanf(argv[i], "--compression_ratio=%lf%c", &d, &junk) == 1) {
      FLAGS_compression_ratio = d;
    } else if (sscanf(argv[i], "--histogram=%d%c", &n, &junk) == 1 &&
               (n == 0 || n == 1)) {
      FLAGS_histogram = n;
    } else if (sscanf(argv[i], "--num=%d%c", &n, &junk) == 1) {
      FLAGS_num = n;
    } else if (sscanf(argv[i], "--reads=%d%c", &n, &junk) == 1) {
      FLAGS_reads = n;
    } else if (sscanf(argv[i], "--value_size=%d%c", &n, &junk) == 1) {
      FLAGS_value_size = n;
    } else if (sscanf(argv[i], "--cache_size=%d%c", &n, &junk) == 1) {
      FLAGS_cache_size = n;
    } else if (sscanf(argv[i], "--page_size=%d%c", &n, &junk) == 1) {
      FLAGS_page_size = n;
    } else if (sscanf(argv[i], "--compression=%d%c", &n, &junk) == 1 &&
               (n == 0 || n == 1)) {
      FLAGS_compression = (n == 1) ? true : false;
    } else if (strncmp(argv[i], "--db=", 5) == 0) {
      FLAGS_db = argv[i] + 5;
    } else {
      std::fprintf(stderr, "Invalid flag '%s'\n", argv[i]);
      std::exit(1);
    }
  }

  // Choose a location for the test database if none given with --db=<path>
  if (FLAGS_db == nullptr) {
    leveldb::Env::Default()->GetTestDirectory(&default_db_path);
    default_db_path += "/dbbench";
    FLAGS_db = default_db_path.c_str();
  }

  leveldb::Benchmark benchmark;
  benchmark.Run();
  return 0;
}
