file_dialog.hpp

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#pragma once


#include <planet/sdl/sdl.hpp>

#include <felspar/io/warden.hpp>

#include <filesystem>


namespace planet::sdl {

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    enum class file_dialog_kind {
        open, // Choose an existing file (`SDL_ShowOpenFileDialog`)
        save, // Name a file to write, which need not yet exist
              // (`SDL_ShowSaveFileDialog`)
        folder, // Choose a folder (`SDL_ShowOpenFolderDialog`)
    };

pattern is a semicolon separated list of extensions without the leading dot, or a single * meaning all files. Not every platform honours filters, and those that do may let the user ignore them.

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    struct file_dialog_filter final {
        std::string name; // e.g. `"Blue Weave project"`
        std::string pattern; // e.g. `"bw-project"`, or `"*"` for all files
    };

Wraps SDL's asynchronous file dialogs as a coroutine: it shows the dialog and resumes once the user has accepted a path, cancelled, or the dialog has errored. folder ignores filters.

parent is the window the dialog is modal for; nullptr leaves it parented to nothing, and not every platform honours it either way. The warden is the one driving the application's event loop; the coroutine yields to it while the dialog is open so SDL keeps pumping the platform (the Linux portal needs this).

Returns the chosen path, or nullopt when the user cancelled or the dialog failed (a failure is logged at error).

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    felspar::io::warden::task<std::optional<std::filesystem::path>> file_dialog(
            felspar::io::warden &,
            file_dialog_kind,
            SDL_Window *parent = nullptr,
            std::optional<std::filesystem::path> default_location = {},
            std::span<file_dialog_filter const> filters = {});

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    std::optional<std::filesystem::path>
            first_selected_path(char const *const *filelist) noexcept;

SDL hands the callback a filelist that is nullptr on error, a pointer to nullptr when the user chose nothing, or a null-terminated array of UTF-8 paths otherwise. This returns the first path if one was chosen, and nullopt for both the error and the nothing-chosen cases (the caller separates those by testing filelist against nullptr itself).

Exposed so the decode can be exercised without opening a dialog.

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}