// Copyright 2015 Google Inc. All rights reserved.
//
// 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.

#include "benchmark/benchmark.h"
#include "complexity.h"

#include <algorithm>
#include <cmath>
#include <cstdint>
#include <iomanip>  // for setprecision
#include <iostream>
#include <limits>
#include <string>
#include <tuple>
#include <vector>

#include "string_util.h"
#include "timers.h"

namespace benchmark {

namespace {

std::string StrEscape(const std::string & s) {
  std::string tmp;
  tmp.reserve(s.size());
  for (char c : s) {
    switch (c) {
    case '\b': tmp += "\\b"; break;
    case '\f': tmp += "\\f"; break;
    case '\n': tmp += "\\n"; break;
    case '\r': tmp += "\\r"; break;
    case '\t': tmp += "\\t"; break;
    case '\\': tmp += "\\\\"; break;
    case '"' : tmp += "\\\""; break;
    default  : tmp += c; break;
    }
  }
  return tmp;
}

std::string FormatKV(std::string const& key, std::string const& value) {
  return StrFormat("\"%s\": \"%s\"", StrEscape(key).c_str(), StrEscape(value).c_str());
}

std::string FormatKV(std::string const& key, const char* value) {
  return StrFormat("\"%s\": \"%s\"", StrEscape(key).c_str(), StrEscape(value).c_str());
}

std::string FormatKV(std::string const& key, bool value) {
  return StrFormat("\"%s\": %s", StrEscape(key).c_str(), value ? "true" : "false");
}

std::string FormatKV(std::string const& key, int64_t value) {
  std::stringstream ss;
  ss << '"' << StrEscape(key) << "\": " << value;
  return ss.str();
}

std::string FormatKV(std::string const& key, IterationCount value) {
  std::stringstream ss;
  ss << '"' << StrEscape(key) << "\": " << value;
  return ss.str();
}

std::string FormatKV(std::string const& key, double value) {
  std::stringstream ss;
  ss << '"' << StrEscape(key) << "\": ";

  if (std::isnan(value))
    ss << (value < 0 ? "-" : "") << "NaN";
  else if (std::isinf(value))
    ss << (value < 0 ? "-" : "") << "Infinity";
  else {
    const auto max_digits10 =
        std::numeric_limits<decltype(value)>::max_digits10;
    const auto max_fractional_digits10 = max_digits10 - 1;
    ss << std::scientific << std::setprecision(max_fractional_digits10)
       << value;
  }
  return ss.str();
}

int64_t RoundDouble(double v) { return std::lround(v); }

}  // end namespace

bool JSONReporter::ReportContext(const Context& context) {
  std::ostream& out = GetOutputStream();

  out << "{\n";
  std::string inner_indent(2, ' ');

  // Open context block and print context information.
  out << inner_indent << "\"context\": {\n";
  std::string indent(4, ' ');

  std::string walltime_value = LocalDateTimeString();
  out << indent << FormatKV("date", walltime_value) << ",\n";

  out << indent << FormatKV("host_name", context.sys_info.name) << ",\n";

  if (Context::executable_name) {
    // windows uses backslash for its path separator,
    // which must be escaped in JSON otherwise it blows up conforming JSON
    // decoders
    std::string executable_name = Context::executable_name;
    auto ReplaceAll = [](std::string* str, const std::string& from, const std::string& to) {
        std::size_t start = 0;
        while ((start = str->find(from, start)) != std::string::npos) {
            str->replace(start, from.length(), to);
            start += to.length();
        }
    };
    ReplaceAll(&executable_name, "\\", "\\\\");
    out << indent << FormatKV("executable", executable_name) << ",\n";
  }

  CPUInfo const& info = context.cpu_info;
  out << indent << FormatKV("num_cpus", static_cast<int64_t>(info.num_cpus))
      << ",\n";
  out << indent
      << FormatKV("mhz_per_cpu",
                  RoundDouble(info.cycles_per_second / 1000000.0))
      << ",\n";
  if (CPUInfo::Scaling::UNKNOWN != info.scaling) {
    out << indent << FormatKV("cpu_scaling_enabled", info.scaling == CPUInfo::Scaling::ENABLED ? true : false)
        << ",\n";
  }

  out << indent << "\"caches\": [\n";
  indent = std::string(6, ' ');
  std::string cache_indent(8, ' ');
  for (size_t i = 0; i < info.caches.size(); ++i) {
    auto& CI = info.caches[i];
    out << indent << "{\n";
    out << cache_indent << FormatKV("type", CI.type) << ",\n";
    out << cache_indent << FormatKV("level", static_cast<int64_t>(CI.level))
        << ",\n";
    out << cache_indent
        << FormatKV("size", static_cast<int64_t>(CI.size)) << ",\n";
    out << cache_indent
        << FormatKV("num_sharing", static_cast<int64_t>(CI.num_sharing))
        << "\n";
    out << indent << "}";
    if (i != info.caches.size() - 1) out << ",";
    out << "\n";
  }
  indent = std::string(4, ' ');
  out << indent << "],\n";
  out << indent << "\"load_avg\": [";
  for (auto it = info.load_avg.begin(); it != info.load_avg.end();) {
    out << *it++;
    if (it != info.load_avg.end()) out << ",";
  }
  out << "],\n";

#if defined(NDEBUG)
  const char build_type[] = "release";
#else
  const char build_type[] = "debug";
#endif
  out << indent << FormatKV("library_build_type", build_type) << "\n";
  // Close context block and open the list of benchmarks.
  out << inner_indent << "},\n";
  out << inner_indent << "\"benchmarks\": [\n";
  return true;
}

void JSONReporter::ReportRuns(std::vector<Run> const& reports) {
  if (reports.empty()) {
    return;
  }
  std::string indent(4, ' ');
  std::ostream& out = GetOutputStream();
  if (!first_report_) {
    out << ",\n";
  }
  first_report_ = false;

  for (auto it = reports.begin(); it != reports.end(); ++it) {
    out << indent << "{\n";
    PrintRunData(*it);
    out << indent << '}';
    auto it_cp = it;
    if (++it_cp != reports.end()) {
      out << ",\n";
    }
  }
}

void JSONReporter::Finalize() {
  // Close the list of benchmarks and the top level object.
  GetOutputStream() << "\n  ]\n}\n";
}

void JSONReporter::PrintRunData(Run const& run) {
  std::string indent(6, ' ');
  std::ostream& out = GetOutputStream();
  out << indent << FormatKV("name", run.benchmark_name()) << ",\n";
  out << indent << FormatKV("run_name", run.run_name.str()) << ",\n";
  out << indent << FormatKV("run_type", [&run]() -> const char* {
    switch (run.run_type) {
      case BenchmarkReporter::Run::RT_Iteration:
        return "iteration";
      case BenchmarkReporter::Run::RT_Aggregate:
        return "aggregate";
    }
    BENCHMARK_UNREACHABLE();
  }()) << ",\n";
  out << indent << FormatKV("repetitions", run.repetitions) << ",\n";
  if (run.run_type != BenchmarkReporter::Run::RT_Aggregate) {
    out << indent << FormatKV("repetition_index", run.repetition_index)
        << ",\n";
  }
  out << indent << FormatKV("threads", run.threads) << ",\n";
  if (run.run_type == BenchmarkReporter::Run::RT_Aggregate) {
    out << indent << FormatKV("aggregate_name", run.aggregate_name) << ",\n";
  }
  if (run.error_occurred) {
    out << indent << FormatKV("error_occurred", run.error_occurred) << ",\n";
    out << indent << FormatKV("error_message", run.error_message) << ",\n";
  }
  if (!run.report_big_o && !run.report_rms) {
    out << indent << FormatKV("iterations", run.iterations) << ",\n";
    out << indent << FormatKV("real_time", run.GetAdjustedRealTime()) << ",\n";
    out << indent << FormatKV("cpu_time", run.GetAdjustedCPUTime());
    out << ",\n"
        << indent << FormatKV("time_unit", GetTimeUnitString(run.time_unit));
  } else if (run.report_big_o) {
    out << indent << FormatKV("cpu_coefficient", run.GetAdjustedCPUTime())
        << ",\n";
    out << indent << FormatKV("real_coefficient", run.GetAdjustedRealTime())
        << ",\n";
    out << indent << FormatKV("big_o", GetBigOString(run.complexity)) << ",\n";
    out << indent << FormatKV("time_unit", GetTimeUnitString(run.time_unit));
  } else if (run.report_rms) {
    out << indent << FormatKV("rms", run.GetAdjustedCPUTime());
  }

  for (auto& c : run.counters) {
    out << ",\n" << indent << FormatKV(c.first, c.second);
  }

  if (run.has_memory_result) {
    out << ",\n" << indent << FormatKV("allocs_per_iter", run.allocs_per_iter);
    out << ",\n" << indent << FormatKV("max_bytes_used", run.max_bytes_used);
  }

  if (!run.report_label.empty()) {
    out << ",\n" << indent << FormatKV("label", run.report_label);
  }
  out << '\n';
}

}  // end namespace benchmark
