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#include <iomanip>
#include <iostream>

#include "src/tint/cmd/bench/bench.h"
#include "src/tint/utils/text/string.h"

/// ChromePerfReporter is a custom benchmark reporter used to output benchmark results in the format
/// required for the Chrome Perf waterfall, as described here:
/// [chromium]//src/tools/perf/generate_legacy_perf_dashboard_json.py
class ChromePerfReporter final : public benchmark::BenchmarkReporter {
  public:
    bool ReportContext([[maybe_unused]] const Context& context) override { return true; }

    void ReportRunsConfig([[maybe_unused]] double min_time,
                          [[maybe_unused]] bool has_explicit_iters,
                          [[maybe_unused]] benchmark::IterationCount iters) override {}

    void ReportRuns(const std::vector<Run>& report) override {
        for (auto& run : report) {
            auto fullname = run.benchmark_name();

            if (run.skipped) {
                std::cout << "FAILED " << fullname << ": " << run.skip_message << "\n";
                continue;
            }

            auto graph_and_trace = tint::Split(fullname, "/");
            TINT_ASSERT(graph_and_trace.Length() <= 2u);
            if (graph_and_trace.Length() == 1u) {
                graph_and_trace.Push(graph_and_trace[0]);
                graph_and_trace[0] = "TintInternals";
            }

            std::cout << "*RESULT " << graph_and_trace[0] << ": " << graph_and_trace[1] << "= "
                      << std::fixed << run.GetAdjustedRealTime() << " ";
            switch (run.time_unit) {
                case benchmark::kNanosecond:
                    std::cout << "ns";
                    break;
                case benchmark::kMicrosecond:
                    std::cout << "us";
                    break;
                case benchmark::kMillisecond:
                    std::cout << "ms";
                    break;
                case benchmark::kSecond:
                    std::cout << "s";
                    break;
            }
            std::cout << "\n";
        }
    }

    void Finalize() override {}
};

int main(int argc, char** argv) {
    benchmark::Initialize(&argc, argv);
    if (benchmark::ReportUnrecognizedArguments(argc, argv)) {
        return 1;
    }
    benchmark::RunSpecifiedBenchmarks(new ChromePerfReporter);
}