#ifndef input_handler_hh_INCLUDED
#define input_handler_hh_INCLUDED

#include "keys.hh"
#include "completion.hh"
#include "utils.hh"
#include "string.hh"
#include "context.hh"

namespace Kakoune
{

class Editor;

enum class MenuEvent
{
    Select,
    Abort,
    Validate
};
using MenuCallback = std::function<void (int, MenuEvent, Context&)>;

enum class PromptEvent
{
    Change,
    Abort,
    Validate
};
using PromptCallback = std::function<void (const String&, PromptEvent, Context&)>;
using KeyCallback = std::function<void (const Key&, Context&)>;

class InputMode;
enum class InsertMode : unsigned;

class InputHandler : public SafeCountable
{
public:
    InputHandler(UserInterface& ui);
    ~InputHandler();

    // switch to insert mode
    void insert(InsertMode mode);
    // repeat last insert mode key sequence
    void repeat_last_insert();

    // enter prompt mode, callback is called on each change,
    // abort or validation with corresponding PromptEvent value
    // returns to normal mode after validation if callback does
    // not change the mode itself
    void prompt(const String& prompt, Completer completer,
                PromptCallback callback);

    // enter menu mode, callback is called on each selection change,
    // abort or validation with corresponding MenuEvent value
    // returns to normal mode after validation if callback does
    // not change the mode itself
    void menu(const memoryview<String>& choices,
              MenuCallback callback);

    // execute callback on next keypress and returns to normal mode
    // if callback does not change the mode itself
    void on_next_key(KeyCallback callback);

    // read and process all inputs available in context
    // user interface
    void handle_available_inputs();

    Context& context() { return m_context; }
private:
    Context m_context;
    friend class InputMode;
    std::unique_ptr<InputMode> m_mode;
    std::vector<std::unique_ptr<InputMode>> m_mode_trash;

    using Insertion = std::pair<InsertMode, std::vector<Key>>;
    Insertion m_last_insert = {InsertMode::Insert, {}};
};

struct prompt_aborted {};

}

#endif // input_handler_hh_INCLUDED