Luna/apps/edit.cpp

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

using os::File;

Result<int> luna_main(int argc, char** argv)
{
    StringView pathname;

    os::ArgumentParser parser;
    parser.add_description("Edit a file using basic line-based shell editing."_sv);
    parser.add_system_program_info("edit"_sv);
    parser.add_positional_argument(pathname, "path"_sv, true);
    parser.parse(argc, argv);

    if (os::FileSystem::exists(pathname))
    {
        String prompt = TRY(String::format("File %s already exists. Overwrite?"_sv, pathname.chars()));
        bool overwrite = os::conditional_prompt(prompt.chars(), os::DefaultNo);
        if (!overwrite) return 0;
    }

    auto file = TRY(File::open_or_create(pathname, File::WriteOnly));

    auto input = File::standard_input();

    os::println("- Editing %s. Press Enter to start a new line, or Ctrl+D at the start of a line to save and exit. -",
                pathname.chars());

    while (1)
    {
        String line = TRY(input->read_line());
        if (line.is_empty()) break;
        TRY(file->write(line.view()));
    }

    return 0;
}