// Copyright 2023 The Dawn & Tint Authors
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#include <iostream>

#include "src/tint/cmd/fuzz/wgsl/fuzz.h"
#include "src/tint/utils/cli/cli.h"
#include "src/tint/utils/macros/defer.h"
#include "src/tint/utils/text/base64.h"

namespace {

tint::fuzz::wgsl::Options options;

}  // namespace

extern "C" int LLVMFuzzerTestOneInput(const uint8_t* input, size_t size) {
    if (size > 0) {
        std::string_view wgsl(reinterpret_cast<const char*>(input), size);
        auto data = tint::DecodeBase64FromComments(wgsl);
        tint::fuzz::wgsl::Run(wgsl, data.Slice(), options);
    }
    return 0;
}

extern "C" int LLVMFuzzerInitialize(int* argc, char*** argv) {
    tint::cli::OptionSet opts;

    tint::Vector<std::string_view, 8> arguments;
    for (int i = 1; i < *argc; i++) {
        std::string_view arg((*argv)[i]);
        if (!arg.empty()) {
            arguments.Push(arg);
        }
    }

    auto show_help = [&] {
        std::cerr << "Custom fuzzer options:" << std::endl;
        opts.ShowHelp(std::cerr);
        std::cerr << std::endl;
        // Change args to show libfuzzer help
        std::cerr << "Standard libfuzzer ";  // libfuzzer will print 'Usage:'
        static char help[] = "-help=1";
        *argc = 2;
        (*argv)[1] = help;
    };

    auto& opt_help = opts.Add<tint::cli::BoolOption>("help", "shows the usage");
    auto& opt_filter = opts.Add<tint::cli::StringOption>(
        "filter", "runs only the fuzzers with the given substring");
    auto& opt_concurrent =
        opts.Add<tint::cli::BoolOption>("concurrent", "runs the fuzzers concurrently");
    auto& opt_verbose =
        opts.Add<tint::cli::BoolOption>("verbose", "prints the name of each fuzzer before running");

    tint::cli::ParseOptions parse_opts;
    parse_opts.ignore_unknown = true;
    if (auto res = opts.Parse(arguments, parse_opts); res != tint::Success) {
        show_help();
        std::cerr << res.Failure();
        return 0;
    }

    if (opt_help.value.value_or(false)) {
        show_help();
        return 0;
    }

    options.filter = opt_filter.value.value_or("");
    options.run_concurrently = opt_concurrent.value.value_or(false);
    options.verbose = opt_verbose.value.value_or(false);
    return 0;
}