Lumacs/include/lumacs/ui_interface.hpp

#pragma once

#include <functional> // Required for EventCallback

namespace lumacs {

// Forward declarations
class EditorCore; 

/// @brief Editor state change events triggered by core actions.
/// Used by the UI layer to react to model updates.
enum class EditorEvent {
    BufferModified,       ///< The content of the active buffer has changed.
    CursorMoved,          ///< The cursor position has changed.
    ViewportChanged,      ///< The visible area (scroll/size) has changed.
    WindowLayoutChanged,  ///< The window tree structure (splits) has changed.
    WindowFocused,        ///< A different window has gained focus.
    Message,              ///< A transient message should be displayed (e.g., in minibuffer).
    
    // Modal Interaction Events
    CommandMode,          ///< Enter command input mode (M-x).
    BufferSwitchMode,     ///< Enter buffer switching mode (C-x b).
    KillBufferMode,       ///< Enter kill buffer mode (C-x k).
    FindFileMode,         ///< Enter file finding mode (C-x C-f).
    ThemeSelectionMode,   ///< Enter theme selection mode.
    ISearchMode,          ///< Enter incremental search mode (C-s).
    ISearchBackwardMode,  ///< Enter backward incremental search mode (C-r).
    
    TransientMessageCleared, ///< A transient message has been cleared.
    Quit,                 ///< The application should exit.
    ThemeChanged          ///< The active theme has changed.
};

/// @brief Abstract interface for a Lumacs editor UI frontend.
/// 
/// All editor UIs (ncurses, GTK, etc.) must implement this interface.
/// This decouples the core logic from the specific display technology.
class IEditorView {
public:
    virtual ~IEditorView() = default;

    /// @brief Initialize the UI system (e.g., ncurses init, GTK window setup).
    /// This should be called before run().
    virtual void init() = 0;

    /// @brief Run the main UI loop. 
    /// This method should block until the UI exits (e.g., gtk_main()).
    virtual void run() = 0;

    /// @brief Handle events emitted by the EditorCore.
    /// The EditorCore will notify the view of model changes (buffer modified, cursor moved).
    /// @param event The event type.
    virtual void handle_editor_event(EditorEvent event) = 0;

    /// @brief Set the EditorCore instance for the view to interact with.
    /// This is typically called once during setup.
    /// @param core Pointer to the core logic instance.
    virtual void set_core(EditorCore* core) = 0;
};

} // namespace lumacs