// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

#include "util/progress-updater.h"

#include "common/logging.h"
#include <sstream>

#include "common/names.h"

using namespace impala;

ProgressUpdater::ProgressUpdater() :
  logging_level_(2), total_(-1), update_period_(0),
  num_complete_(0), last_output_percentage_(0) {
}

void ProgressUpdater::Init(const string& label, int64_t total, int update_period) {
  DCHECK_GE(total, 0);
  label_ = label;
  total_ = total;
  update_period_ = update_period;
  DCHECK_EQ(num_complete_.Load(), 0) << "Update() should not have been called yet";
  DCHECK_EQ(last_output_percentage_.Load(), 0);
}

void ProgressUpdater::Update(int64_t delta) {
  DCHECK_GE(total_, 0) << "Init() should have been called already";
  DCHECK_GE(delta, 0);
  if (delta == 0) return;

  num_complete_.Add(delta);

  // Cache some shared variables to avoid locking.  It's possible the progress
  // update is out of order (e.g. prints 1 out of 10 after 2 out of 10)
  double old_percentage = last_output_percentage_.Load();
  int64_t num_complete = num_complete_.Load();

  if (num_complete >= total_) {
    // Always print the final 100% complete
    VLOG(logging_level_) << label_ << " 100% Complete ("
                         << num_complete << " out of " << total_ << ")";
    return;
  }

  // Convert to percentage as int
  int new_percentage = (static_cast<double>(num_complete) / total_) * 100;
  if (new_percentage - old_percentage > update_period_) {
    // Only update shared variable if this guy was the latest.
    last_output_percentage_.CompareAndSwap(old_percentage, new_percentage);
    VLOG(logging_level_) << label_ << ": " << new_percentage << "% Complete ("
                         << num_complete << " out of " << total_ << ")";
  }
}

string ProgressUpdater::ToString() const {
  stringstream ss;
  int64_t num_complete = num_complete_.Load();
  if (num_complete >= total_) {
    // Always print the final 100% complete
    ss << label_ << " 100% Complete (" << num_complete << " out of " << total_ << ")";
    return ss.str();
  }
  int percentage = (static_cast<double>(num_complete) / total_) * 100;
  ss << label_ << ": " << percentage << "% Complete ("
     << num_complete << " out of " << total_ << ")";
  return ss.str();
}