/*
 * Copyright 2018 The Android Open Source Project
 *
 * Licensed 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.
 */

#pragma once

#include "tuningfork_internal.h"

#include <inttypes.h>
#include <vector>
#include <string>

namespace tuningfork {

class Histogram {
    typedef double Sample;
    static constexpr int kAutoSizeNumStdDev = 3;
    static constexpr double kAutoSizeMinBucketSizeMs = 0.1;
    Sample start_ms_, end_ms_, bucket_dt_ms_;
    uint32_t num_buckets_;
    std::vector<uint32_t> buckets_;
    std::vector<Sample> samples_;
    bool auto_range_;
    size_t count_;
public:
    static constexpr int kDefaultNumBuckets = 30;

    explicit Histogram(float start_ms = 0, float end_ms = 0, int num_buckets_between = kDefaultNumBuckets);
    explicit Histogram(const Settings::Histogram&);

    // Add a sample delta time
    void Add(Sample dt_ms);

    // Reset the histogram
    void Clear(bool autorange = false);

    // Get the total number of samples added so far
    size_t Count() const { return count_; }

    // Get the histogram as a JSON object, for testing
    std::string ToJSON() const;

    // Use the data we have to construct the bucket ranges. This is called automatically after
    //  sizeAtWhichToRange samples have been collected, if we are auto-ranging.
    void CalcBucketsFromSamples();

    friend class ClearcutSerializer;
};

} // namespace tuningfork {