#include <luna/String.h>
#include <os/ArgumentParser.h>
#include <os/File.h>

using os::File;

static Result<void> do_cat(StringView path)
{
    SharedPtr<File> f = TRY(File::open_input_file(path));

    auto out = File::standard_output();

    auto buf = TRY(Buffer::create_sized(4096));
    while (1)
    {
        TRY(f->read(buf, 4096));
        if (buf.is_empty()) break;
        out->write(buf);
    }

    return {};
}

Result<int> luna_main(int argc, char** argv)
{
    StringView filename;
    Vector<StringView> files;

    os::ArgumentParser parser;
    parser.add_description("Concatenate files to standard output."_sv);
    parser.add_system_program_info("cat"_sv);
    parser.add_positional_argument(filename, "file"_sv, "-"_sv);
    parser.set_vector_argument(files);
    parser.parse(argc, argv);

    TRY(do_cat(filename));

    for (auto file : files) TRY(do_cat(file));

    return 0;
}