ladybird/Libraries/LibGUI/GTextEditor.h

#pragma once

#include <AK/Function.h>
#include <AK/HashMap.h>
#include <AK/NonnullOwnPtrVector.h>
#include <AK/NonnullRefPtrVector.h>
#include <LibDraw/TextAlignment.h>
#include <LibGUI/GScrollableWidget.h>

class GAction;
class GMenu;
class GScrollBar;
class Painter;

enum class ShouldWrapAtEndOfDocument { No = 0, Yes };
enum class ShouldWrapAtStartOfDocument { No = 0, Yes };

class GTextPosition {
public:
    GTextPosition() {}
    GTextPosition(int line, int column)
        : m_line(line)
        , m_column(column)
    {
    }

    bool is_valid() const { return m_line >= 0 && m_column >= 0; }

    int line() const { return m_line; }
    int column() const { return m_column; }

    void set_line(int line) { m_line = line; }
    void set_column(int column) { m_column = column; }

    bool operator==(const GTextPosition& other) const { return m_line == other.m_line && m_column == other.m_column; }
    bool operator!=(const GTextPosition& other) const { return m_line != other.m_line || m_column != other.m_column; }
    bool operator<(const GTextPosition& other) const { return m_line < other.m_line || (m_line == other.m_line && m_column < other.m_column); }

private:
    int m_line { -1 };
    int m_column { -1 };
};

class GTextRange {
public:
    GTextRange() {}
    GTextRange(const GTextPosition& start, const GTextPosition& end)
        : m_start(start)
        , m_end(end)
    {
    }

    bool is_valid() const { return m_start.is_valid() && m_end.is_valid(); }
    void clear()
    {
        m_start = {};
        m_end = {};
    }

    GTextPosition& start() { return m_start; }
    GTextPosition& end() { return m_end; }
    const GTextPosition& start() const { return m_start; }
    const GTextPosition& end() const { return m_end; }

    GTextRange normalized() const { return GTextRange(normalized_start(), normalized_end()); }

    void set_start(const GTextPosition& position) { m_start = position; }
    void set_end(const GTextPosition& position) { m_end = position; }

    void set(const GTextPosition& start, const GTextPosition& end)
    {
        m_start = start;
        m_end = end;
    }

    bool operator==(const GTextRange& other) const
    {
        return m_start == other.m_start && m_end == other.m_end;
    }

private:
    GTextPosition normalized_start() const { return m_start < m_end ? m_start : m_end; }
    GTextPosition normalized_end() const { return m_start < m_end ? m_end : m_start; }

    GTextPosition m_start;
    GTextPosition m_end;
};

class GTextEditor : public GScrollableWidget {
    C_OBJECT(GTextEditor)
public:
    enum Type {
        MultiLine,
        SingleLine
    };
    virtual ~GTextEditor() override;

    bool is_readonly() const { return m_readonly; }
    void set_readonly(bool);

    bool is_automatic_indentation_enabled() const { return m_automatic_indentation_enabled; }
    void set_automatic_indentation_enabled(bool enabled) { m_automatic_indentation_enabled = enabled; }

    bool is_line_wrapping_enabled() const { return m_line_wrapping_enabled; }
    void set_line_wrapping_enabled(bool);

    TextAlignment text_alignment() const { return m_text_alignment; }
    void set_text_alignment(TextAlignment);

    Type type() const { return m_type; }
    bool is_single_line() const { return m_type == SingleLine; }
    bool is_multi_line() const { return m_type == MultiLine; }

    bool is_ruler_visible() const { return m_ruler_visible; }
    void set_ruler_visible(bool b) { m_ruler_visible = b; }

    Function<void()> on_cursor_change;
    Function<void()> on_selection_change;

    void set_text(const StringView&);
    void scroll_cursor_into_view();
    void scroll_position_into_view(const GTextPosition&);
    int line_count() const { return m_lines.size(); }
    int line_spacing() const { return m_line_spacing; }
    int line_height() const { return font().glyph_height() + m_line_spacing; }
    GTextPosition cursor() const { return m_cursor; }
    GTextRange normalized_selection() const { return m_selection.normalized(); }
    // FIXME: This should take glyph spacing into account, no?
    int glyph_width() const { return font().glyph_width('x'); }

    bool write_to_file(const StringView& path);

    GTextRange find_next(const StringView&, const GTextPosition& start = {});
    GTextRange find_prev(const StringView&, const GTextPosition& start = {});

    GTextPosition next_position_after(const GTextPosition&, ShouldWrapAtEndOfDocument = ShouldWrapAtEndOfDocument::Yes);
    GTextPosition prev_position_before(const GTextPosition&, ShouldWrapAtStartOfDocument = ShouldWrapAtStartOfDocument::Yes);

    bool has_selection() const { return m_selection.is_valid(); }
    String selected_text() const;
    void set_selection(const GTextRange&);

    String text() const;

    void clear();

    void cut();
    void copy();
    void paste();
    void do_delete();
    void delete_current_line();
    void select_all();

    Function<void()> on_change;
    Function<void()> on_return_pressed;
    Function<void()> on_escape_pressed;

    GAction& undo_action() { return *m_undo_action; }
    GAction& redo_action() { return *m_redo_action; }
    GAction& cut_action() { return *m_cut_action; }
    GAction& copy_action() { return *m_copy_action; }
    GAction& paste_action() { return *m_paste_action; }
    GAction& delete_action() { return *m_delete_action; }

    void add_custom_context_menu_action(GAction&);

    void set_cursor(int line, int column);
    void set_cursor(const GTextPosition&);

    struct Span {
        bool contains(const GTextPosition& position) const
        {
            if (!(position.line() > start.line() || (position.line() == start.line() && position.column() >= start.column())))
                return false;
            if (!(position.line() < end.line() || (position.line() == end.line() && position.column() <= end.column())))
                return false;
            return true;
        }

        GTextPosition start;
        GTextPosition end;
        Color color;
        const Font* font { nullptr };
    };

    void set_spans(const Vector<Span>& spans)
    {
        m_spans = spans;
    }

protected:
    GTextEditor(Type, GWidget* parent);

    virtual void did_change_font() override;
    virtual void paint_event(GPaintEvent&) override;
    virtual void mousedown_event(GMouseEvent&) override;
    virtual void mouseup_event(GMouseEvent&) override;
    virtual void mousemove_event(GMouseEvent&) override;
    virtual void doubleclick_event(GMouseEvent&) override;
    virtual void keydown_event(GKeyEvent&) override;
    virtual void focusin_event(CEvent&) override;
    virtual void focusout_event(CEvent&) override;
    virtual void timer_event(CTimerEvent&) override;
    virtual bool accepts_focus() const override { return true; }
    virtual void enter_event(CEvent&) override;
    virtual void leave_event(CEvent&) override;
    virtual void context_menu_event(GContextMenuEvent&) override;
    virtual void resize_event(GResizeEvent&) override;

private:
    void create_actions();
    void paint_ruler(Painter&);
    void update_content_size();
    void did_change();

    class Line {
        friend class GTextEditor;

    public:
        explicit Line(GTextEditor&);
        Line(GTextEditor&, const StringView&);

        StringView view() const { return { characters(), length() }; }
        const char* characters() const { return m_text.data(); }
        int length() const { return m_text.size() - 1; }
        void set_text(const StringView&);
        void append(char);
        void prepend(char);
        void insert(int index, char);
        void remove(int index);
        void append(const char*, int);
        void truncate(int length);
        void clear();
        void recompute_visual_lines();
        int visual_line_containing(int column) const;
        int first_non_whitespace_column() const;

        template<typename Callback>
        void for_each_visual_line(Callback) const;

    private:
        GTextEditor& m_editor;

        // NOTE: This vector is null terminated.
        Vector<char> m_text;

        Vector<int, 1> m_visual_line_breaks;
        Rect m_visual_rect;
    };

    Rect line_content_rect(int item_index) const;
    Rect line_widget_rect(int line_index) const;
    Rect cursor_content_rect() const;
    Rect content_rect_for_position(const GTextPosition&) const;
    void update_cursor();
    Line& current_line() { return m_lines[m_cursor.line()]; }
    const Line& current_line() const { return m_lines[m_cursor.line()]; }
    GTextPosition text_position_at(const Point&) const;
    void insert_at_cursor(char);
    void insert_at_cursor(const StringView&);
    int ruler_width() const;
    Rect ruler_content_rect(int line) const;
    void toggle_selection_if_needed_for_event(const GKeyEvent&);
    void insert_at_cursor_or_replace_selection(const StringView&);
    void delete_selection();
    void did_update_selection();
    int content_x_for_position(const GTextPosition&) const;
    char character_at(const GTextPosition&) const;
    Rect ruler_rect_in_inner_coordinates() const;
    Rect visible_text_rect_in_inner_coordinates() const;
    void recompute_all_visual_lines();

    Type m_type { MultiLine };

    NonnullOwnPtrVector<Line> m_lines;
    GTextPosition m_cursor;
    TextAlignment m_text_alignment { TextAlignment::CenterLeft };
    bool m_cursor_state { true };
    bool m_in_drag_select { false };
    bool m_ruler_visible { false };
    bool m_have_pending_change_notification { false };
    bool m_automatic_indentation_enabled { false };
    bool m_line_wrapping_enabled { false };
    bool m_readonly { false };
    int m_line_spacing { 4 };
    int m_soft_tab_width { 4 };
    int m_horizontal_content_padding { 2 };
    GTextRange m_selection;
    OwnPtr<GMenu> m_context_menu;
    RefPtr<GAction> m_undo_action;
    RefPtr<GAction> m_redo_action;
    RefPtr<GAction> m_cut_action;
    RefPtr<GAction> m_copy_action;
    RefPtr<GAction> m_paste_action;
    RefPtr<GAction> m_delete_action;
    CElapsedTimer m_triple_click_timer;
    NonnullRefPtrVector<GAction> m_custom_context_menu_actions;

    Vector<Span> m_spans;
};

inline const LogStream& operator<<(const LogStream& stream, const GTextPosition& value)
{
    if (!value.is_valid())
        return stream << "GTextPosition(Invalid)";
    return stream << String::format("(%d,%d)", value.line(), value.column());
}

inline const LogStream& operator<<(const LogStream& stream, const GTextRange& value)
{
    if (!value.is_valid())
        return stream << "GTextRange(Invalid)";
    return stream << value.start() << '-' << value.end();
}