/*
4coder_base_commands.cpp - Base commands such as inserting characters, and
moving the cursor, which work even without the default 4coder framework.
*/

// TOP

function void
write_text(Application_Links *app, String_Const_u8 insert){
    ProfileScope(app, "write character");
    if (insert.str != 0 && insert.size > 0){
        View_ID view = get_active_view(app, Access_ReadWriteVisible);
        if_view_has_highlighted_range_delete_range(app, view);
        
        i64 pos = view_get_cursor_pos(app, view);
        pos = view_get_character_legal_pos_from_pos(app, view, pos);
        
        Buffer_ID buffer = view_get_buffer(app, view, Access_ReadWriteVisible);
        
        // NOTE(allen): consecutive inserts merge logic
        History_Record_Index first_index = buffer_history_get_current_state_index(app, buffer);
        b32 do_merge = false;
        if (insert.str[0] != '\n'){
            Record_Info record = get_single_record(app, buffer, first_index);
            if (record.error == RecordError_NoError && record.kind == RecordKind_Single){
                String_Const_u8 string = record.single_string_forward;
                i32 last_end = (i32)(record.single_first + string.size);
                if (last_end == pos && string.size > 0){
                    char c = string.str[string.size - 1];
                    if (c != '\n'){
                        if (character_is_whitespace(insert.str[0]) &&
                            character_is_whitespace(c)){
                            do_merge = true;
                        }
                        else if (character_is_alpha_numeric(insert.str[0]) && character_is_alpha_numeric(c)){
                            do_merge = true;
                        }
                    }
                }
            }
        }
        
        // NOTE(allen): perform the edit
        b32 edit_success = buffer_replace_range(app, buffer, Ii64(pos), insert);
        
        // NOTE(allen): finish merging records if necessary
        if (do_merge){
            History_Record_Index last_index = buffer_history_get_current_state_index(app, buffer);
            buffer_history_merge_record_range(app, buffer, first_index, last_index, RecordMergeFlag_StateInRange_MoveStateForward);
        }
        
        // NOTE(allen): finish updating the cursor
        if (edit_success){
            view_set_cursor_and_preferred_x(app, view, seek_pos(pos + insert.size));
        }
    }
}

CUSTOM_COMMAND_SIG(write_text_input)
CUSTOM_DOC("Inserts whatever text was used to trigger this command.")
{
    User_Input in = get_current_input(app);
    String_Const_u8 insert = to_writable(&in);
    write_text(app, insert);
}

CUSTOM_COMMAND_SIG(write_space)
CUSTOM_DOC("Inserts a space.")
{
    write_text(app, string_u8_litexpr(" "));
}

CUSTOM_COMMAND_SIG(write_underscore)
CUSTOM_DOC("Inserts an underscore.")
{
    write_text(app, string_u8_litexpr("_"));
}

CUSTOM_COMMAND_SIG(delete_char)
CUSTOM_DOC("Deletes the character to the right of the cursor.")
{
    View_ID view = get_active_view(app, Access_ReadWriteVisible);
    if (!if_view_has_highlighted_range_delete_range(app, view)){
        Buffer_ID buffer = view_get_buffer(app, view, Access_ReadWriteVisible);
        i64 start = view_get_cursor_pos(app, view);
        i64 buffer_size = buffer_get_size(app, buffer);
        if (0 <= start && start < buffer_size){
            Buffer_Cursor cursor = view_compute_cursor(app, view, seek_pos(start));
            i64 character = view_relative_character_from_pos(app, view, cursor.line, cursor.pos);
            i64 end = view_pos_from_relative_character(app, view, cursor.line, character + 1);
            buffer_replace_range(app, buffer, Ii64(start, end), string_u8_empty);
        }
    }
}

CUSTOM_COMMAND_SIG(backspace_char)
CUSTOM_DOC("Deletes the character to the left of the cursor.")
{
    View_ID view = get_active_view(app, Access_ReadWriteVisible);
    if (!if_view_has_highlighted_range_delete_range(app, view)){
        Buffer_ID buffer = view_get_buffer(app, view, Access_ReadWriteVisible);
        i64 end = view_get_cursor_pos(app, view);
        i64 buffer_size = buffer_get_size(app, buffer);
        if (0 < end && end <= buffer_size){
            Buffer_Cursor cursor = view_compute_cursor(app, view, seek_pos(end));
            i64 character = view_relative_character_from_pos(app, view, cursor.line, cursor.pos);
            i64 start = view_pos_from_relative_character(app, view, cursor.line, character - 1);
            if (buffer_replace_range(app, buffer, Ii64(start, end), string_u8_empty)){
                view_set_cursor_and_preferred_x(app, view, seek_pos(start));
            }
        }
    }
}

CUSTOM_COMMAND_SIG(set_mark)
CUSTOM_DOC("Sets the mark to the current position of the cursor.")
{
    View_ID view = get_active_view(app, Access_ReadVisible);
    i64 pos = view_get_cursor_pos(app, view);
    view_set_mark(app, view, seek_pos(pos));
    view_set_cursor_and_preferred_x(app, view, seek_pos(pos));
}

CUSTOM_COMMAND_SIG(cursor_mark_swap)
CUSTOM_DOC("Swaps the position of the cursor and the mark.")
{
    View_ID view = get_active_view(app, Access_ReadVisible);
    i64 cursor = view_get_cursor_pos(app, view);
    i64 mark = view_get_mark_pos(app, view);
    view_set_cursor_and_preferred_x(app, view, seek_pos(mark));
    view_set_mark(app, view, seek_pos(cursor));
}

CUSTOM_COMMAND_SIG(delete_range)
CUSTOM_DOC("Deletes the text in the range between the cursor and the mark.")
{
    View_ID view = get_active_view(app, Access_ReadWriteVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadWriteVisible);
    Range_i64 range = get_view_range(app, view);
    buffer_replace_range(app, buffer, range, string_u8_empty);
}

function  void
current_view_boundary_delete(Application_Links *app, Scan_Direction direction, Boundary_Function_List funcs){
    View_ID view = get_active_view(app, Access_ReadWriteVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadWriteVisible);
    Range_i64 range = {};
    range.first = view_get_cursor_pos(app, view);
    range.one_past_last = scan(app, funcs, buffer, direction, range.first);
    range = rectify(range);
    buffer_replace_range(app, buffer, range, string_u8_empty);
}

CUSTOM_COMMAND_SIG(backspace_alpha_numeric_boundary)
CUSTOM_DOC("Delete characters between the cursor position and the first alphanumeric boundary to the left.")
{
    Scratch_Block scratch(app);
    current_view_boundary_delete(app, Scan_Backward, push_boundary_list(scratch, boundary_alpha_numeric));
}

CUSTOM_COMMAND_SIG(delete_alpha_numeric_boundary)
CUSTOM_DOC("Delete characters between the cursor position and the first alphanumeric boundary to the right.")
{
    Scratch_Block scratch(app);
    current_view_boundary_delete(app, Scan_Forward, push_boundary_list(scratch, boundary_alpha_numeric));
}

function void
current_view_snipe_delete(Application_Links *app, Scan_Direction direction, Boundary_Function_List funcs){
    View_ID view = get_active_view(app, Access_ReadWriteVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadWriteVisible);
    i64 pos = view_get_cursor_pos(app, view);
    Range_i64 range = get_snipe_range(app, funcs, buffer, pos, direction);
    buffer_replace_range(app, buffer, range, string_u8_litexpr(""));
}

CUSTOM_COMMAND_SIG(snipe_backward_whitespace_or_token_boundary)
CUSTOM_DOC("Delete a single, whole token on or to the left of the cursor and post it to the clipboard.")
{
    Scratch_Block scratch(app);
    current_view_snipe_delete(app, Scan_Backward,
                              push_boundary_list(scratch, boundary_token, boundary_non_whitespace));
}

CUSTOM_COMMAND_SIG(snipe_forward_whitespace_or_token_boundary)
CUSTOM_DOC("Delete a single, whole token on or to the right of the cursor and post it to the clipboard.")
{
    Scratch_Block scratch(app);
    current_view_snipe_delete(app, Scan_Forward,
                              push_boundary_list(scratch, boundary_token, boundary_non_whitespace));
}

////////////////////////////////

CUSTOM_COMMAND_SIG(center_view)
CUSTOM_DOC("Centers the view vertically on the line on which the cursor sits.")
{
    View_ID view = get_active_view(app, Access_ReadVisible);
    Rect_f32 region = view_get_buffer_region(app, view);
    i64 pos = view_get_cursor_pos(app, view);
    Buffer_Cursor cursor = view_compute_cursor(app, view, seek_pos(pos));
    f32 view_height = rect_height(region);
    Buffer_Scroll scroll = view_get_buffer_scroll(app, view);
    scroll.target.line_number = cursor.line;
    scroll.target.pixel_shift.y = -view_height*0.5f;
    view_set_buffer_scroll(app, view, scroll, SetBufferScroll_SnapCursorIntoView);
    no_mark_snap_to_cursor(app, view);
}

CUSTOM_COMMAND_SIG(left_adjust_view)
CUSTOM_DOC("Sets the left size of the view near the x position of the cursor.")
{
    View_ID view = get_active_view(app, Access_ReadVisible);
    i64 pos = view_get_cursor_pos(app, view);
    Buffer_Cursor cursor = view_compute_cursor(app, view, seek_pos(pos));
    Vec2_f32 p = view_relative_xy_of_pos(app, view, cursor.line, pos);
    Buffer_Scroll scroll = view_get_buffer_scroll(app, view);
    scroll.target.pixel_shift.x = clamp_bot(0.f, p.x - 30.f);
    view_set_buffer_scroll(app, view, scroll, SetBufferScroll_SnapCursorIntoView);
    no_mark_snap_to_cursor(app, view);
}

CUSTOM_COMMAND_SIG(click_set_cursor_and_mark)
CUSTOM_DOC("Sets the cursor position and mark to the mouse position.")
{
    View_ID view = get_active_view(app, Access_ReadVisible);
    Mouse_State mouse = get_mouse_state(app);
    i64 pos = view_pos_from_xy(app, view, V2f32(mouse.p));
    view_set_cursor_and_preferred_x(app, view, seek_pos(pos));
    view_set_mark(app, view, seek_pos(pos));
}

CUSTOM_COMMAND_SIG(click_set_cursor)
CUSTOM_DOC("Sets the cursor position to the mouse position.")
{
    View_ID view = get_active_view(app, Access_ReadVisible);
    Mouse_State mouse = get_mouse_state(app);
    i64 pos = view_pos_from_xy(app, view, V2f32(mouse.p));
    view_set_cursor_and_preferred_x(app, view, seek_pos(pos));
    no_mark_snap_to_cursor(app, view);
}

CUSTOM_COMMAND_SIG(click_set_cursor_if_lbutton)
CUSTOM_DOC("If the mouse left button is pressed, sets the cursor position to the mouse position.")
{
    View_ID view = get_active_view(app, Access_ReadVisible);
    Mouse_State mouse = get_mouse_state(app);
    if (mouse.l){
        i64 pos = view_pos_from_xy(app, view, V2f32(mouse.p));
        view_set_cursor_and_preferred_x(app, view, seek_pos(pos));
    }
    no_mark_snap_to_cursor(app, view);
}

CUSTOM_COMMAND_SIG(click_set_mark)
CUSTOM_DOC("Sets the mark position to the mouse position.")
{
    View_ID view = get_active_view(app, Access_ReadVisible);
    Mouse_State mouse = get_mouse_state(app);
    i64 pos = view_pos_from_xy(app, view, V2f32(mouse.p));
    view_set_mark(app, view, seek_pos(pos));
    no_mark_snap_to_cursor(app, view);
}

CUSTOM_COMMAND_SIG(mouse_wheel_scroll)
CUSTOM_DOC("Reads the scroll wheel value from the mouse state and scrolls accordingly.")
{
    View_ID view = get_active_view(app, Access_ReadVisible);
    Mouse_State mouse = get_mouse_state(app);
    if (mouse.wheel != 0){
        Buffer_Scroll scroll = view_get_buffer_scroll(app, view);
        scroll.target = view_move_buffer_point(app, view, scroll.target, V2f32(0.f, (f32)mouse.wheel));
        view_set_buffer_scroll(app, view, scroll, SetBufferScroll_SnapCursorIntoView);
    }
    no_mark_snap_to_cursor(app, view);
}

////////////////////////////////

internal void
move_vertical_pixels(Application_Links *app, View_ID view, f32 pixels){
    ProfileScope(app, "move vertical pixels");
    i64 pos = view_get_cursor_pos(app, view);
    Buffer_Cursor cursor = view_compute_cursor(app, view, seek_pos(pos));
    Rect_f32 r = view_padded_box_of_pos(app, view, cursor.line, pos);
    Vec2_f32 p = {};
    p.x = view_get_preferred_x(app, view);
    if (pixels > 0.f){
        p.y = r.y1 + pixels;
    }
    else{
        p.y = r.y0 + pixels;
    }
    i64 new_pos = view_pos_at_relative_xy(app, view, cursor.line, p);
    view_set_cursor(app, view, seek_pos(new_pos));
    no_mark_snap_to_cursor_if_shift(app, view);
}

internal void
move_vertical_pixels(Application_Links *app, f32 pixels){
    View_ID view = get_active_view(app, Access_ReadVisible);
    move_vertical_pixels(app, view, pixels);
}

internal void
move_vertical_lines(Application_Links *app, View_ID view, i64 lines){
    if (lines > 0){
        for (i64 i = 0; i < lines; i += 1){
            move_vertical_pixels(app, 1.f);
        }
    }
    else{
        for (i64 i = 0; i > lines; i -= 1){
            move_vertical_pixels(app, -1.f);
        }
    }
}

internal void
move_vertical_lines(Application_Links *app, i64 lines){
    View_ID view = get_active_view(app, Access_ReadVisible);
    move_vertical_lines(app, view, lines);
}

internal f32
get_page_jump(Application_Links *app, View_ID view){
    Rect_f32 region = view_get_buffer_region(app, view);
    return(rect_height(region)*.9f);
}

CUSTOM_COMMAND_SIG(move_up)
CUSTOM_DOC("Moves the cursor up one line.")
{
    move_vertical_lines(app, -1);
}

CUSTOM_COMMAND_SIG(move_down)
CUSTOM_DOC("Moves the cursor down one line.")
{
    move_vertical_lines(app, 1);
}

CUSTOM_COMMAND_SIG(move_up_10)
CUSTOM_DOC("Moves the cursor up ten lines.")
{
    move_vertical_lines(app, -10);
}

CUSTOM_COMMAND_SIG(move_down_10)
CUSTOM_DOC("Moves the cursor down ten lines.")
{
    move_vertical_lines(app, 10);
}

CUSTOM_COMMAND_SIG(move_down_textual)
CUSTOM_DOC("Moves down to the next line of actual text, regardless of line wrapping.")
{
    View_ID view = get_active_view(app, Access_ReadWriteVisible);
    i64 pos = view_get_cursor_pos(app, view);
    Buffer_Cursor cursor = view_compute_cursor(app, view, seek_pos(pos));
    i64 next_line = cursor.line + 1;
    view_set_cursor_and_preferred_x(app, view, seek_line_col(next_line, 1));
}

CUSTOM_COMMAND_SIG(page_up)
CUSTOM_DOC("Scrolls the view up one view height and moves the cursor up one view height.")
{
    View_ID view = get_active_view(app, Access_ReadVisible);
    f32 page_jump = get_page_jump(app, view);
    move_vertical_pixels(app, -page_jump);
}

CUSTOM_COMMAND_SIG(page_down)
CUSTOM_DOC("Scrolls the view down one view height and moves the cursor down one view height.")
{
    View_ID view = get_active_view(app, Access_ReadVisible);
    f32 page_jump = get_page_jump(app, view);
    move_vertical_pixels(app, page_jump);
}

internal void
seek_blank_line(Application_Links *app, Scan_Direction direction, Position_Within_Line position){
    View_ID view = get_active_view(app, Access_ReadVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadVisible);
    i64 pos = view_get_cursor_pos(app, view);
    i64 new_pos = get_pos_of_blank_line_grouped(app, buffer, direction, pos);
    switch (position){
        case PositionWithinLine_SkipLeadingWhitespace:
        {
            new_pos = get_pos_past_lead_whitespace(app, buffer, new_pos);
        }break;
        case PositionWithinLine_End:
        {
            new_pos = get_line_side_pos_from_pos(app, buffer, new_pos, Side_Max);
        }break;
    }
    new_pos = view_get_character_legal_pos_from_pos(app, view, new_pos);
    view_set_cursor_and_preferred_x(app, view, seek_pos(new_pos));
    no_mark_snap_to_cursor_if_shift(app, view);
}

CUSTOM_COMMAND_SIG(move_up_to_blank_line)
CUSTOM_DOC("Seeks the cursor up to the next blank line.")
{
    seek_blank_line(app, Scan_Backward, PositionWithinLine_Start);
}

CUSTOM_COMMAND_SIG(move_down_to_blank_line)
CUSTOM_DOC("Seeks the cursor down to the next blank line.")
{
    seek_blank_line(app, Scan_Forward, PositionWithinLine_Start);
}

CUSTOM_COMMAND_SIG(move_up_to_blank_line_skip_whitespace)
CUSTOM_DOC("Seeks the cursor up to the next blank line and places it at the end of the line.")
{
    seek_blank_line(app, Scan_Backward, PositionWithinLine_SkipLeadingWhitespace);
}

CUSTOM_COMMAND_SIG(move_down_to_blank_line_skip_whitespace)
CUSTOM_DOC("Seeks the cursor down to the next blank line and places it at the end of the line.")
{
    seek_blank_line(app, Scan_Forward, PositionWithinLine_SkipLeadingWhitespace);
}

CUSTOM_COMMAND_SIG(move_up_to_blank_line_end)
CUSTOM_DOC("Seeks the cursor up to the next blank line and places it at the end of the line.")
{
    seek_blank_line(app, Scan_Backward, PositionWithinLine_End);
}

CUSTOM_COMMAND_SIG(move_down_to_blank_line_end)
CUSTOM_DOC("Seeks the cursor down to the next blank line and places it at the end of the line.")
{
    seek_blank_line(app, Scan_Forward, PositionWithinLine_End);
}

CUSTOM_COMMAND_SIG(move_left)
CUSTOM_DOC("Moves the cursor one character to the left.")
{
    View_ID view = get_active_view(app, Access_ReadVisible);
    view_set_cursor_by_character_delta(app, view, -1);
    no_mark_snap_to_cursor_if_shift(app, view);
}

CUSTOM_COMMAND_SIG(move_right)
CUSTOM_DOC("Moves the cursor one character to the right.")
{
    View_ID view = get_active_view(app, Access_ReadVisible);
    view_set_cursor_by_character_delta(app, view, 1);
    no_mark_snap_to_cursor_if_shift(app, view);
}

function void
current_view_scan_move(Application_Links *app, Scan_Direction direction, Boundary_Function_List funcs){
    View_ID view = get_active_view(app, Access_ReadVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadVisible);
    i64 cursor_pos = view_get_cursor_pos(app, view);
    i64 pos = scan(app, funcs, buffer, direction, cursor_pos);
    view_set_cursor_and_preferred_x(app, view, seek_pos(pos));
    no_mark_snap_to_cursor_if_shift(app, view);
}

CUSTOM_COMMAND_SIG(move_right_whitespace_boundary)
CUSTOM_DOC("Seek right for the next boundary between whitespace and non-whitespace.")
{
    Scratch_Block scratch(app);
    current_view_scan_move(app, Scan_Forward,
                           push_boundary_list(scratch, boundary_non_whitespace));
}

CUSTOM_COMMAND_SIG(move_left_whitespace_boundary)
CUSTOM_DOC("Seek left for the next boundary between whitespace and non-whitespace.")
{
    Scratch_Block scratch(app);
    current_view_scan_move(app, Scan_Backward,
                           push_boundary_list(scratch, boundary_non_whitespace));
}

CUSTOM_COMMAND_SIG(move_right_token_boundary)
CUSTOM_DOC("Seek right for the next end of a token.")
{
    Scratch_Block scratch(app);
    current_view_scan_move(app, Scan_Forward, push_boundary_list(scratch, boundary_token));
}

CUSTOM_COMMAND_SIG(move_left_token_boundary)
CUSTOM_DOC("Seek left for the next beginning of a token.")
{
    Scratch_Block scratch(app);
    current_view_scan_move(app, Scan_Backward, push_boundary_list(scratch, boundary_token));
}

CUSTOM_COMMAND_SIG(move_right_whitespace_or_token_boundary)
CUSTOM_DOC("Seek right for the next end of a token or boundary between whitespace and non-whitespace.")
{
    Scratch_Block scratch(app);
    current_view_scan_move(app, Scan_Forward, push_boundary_list(scratch, boundary_token, boundary_non_whitespace));
}

CUSTOM_COMMAND_SIG(move_left_whitespace_or_token_boundary)
CUSTOM_DOC("Seek left for the next end of a token or boundary between whitespace and non-whitespace.")
{
    Scratch_Block scratch(app);
    current_view_scan_move(app, Scan_Backward, push_boundary_list(scratch, boundary_token, boundary_non_whitespace));
}

CUSTOM_COMMAND_SIG(move_right_alpha_numeric_boundary)
CUSTOM_DOC("Seek right for boundary between alphanumeric characters and non-alphanumeric characters.")
{
    Scratch_Block scratch(app);
    current_view_scan_move(app, Scan_Forward, push_boundary_list(scratch, boundary_alpha_numeric));
}

CUSTOM_COMMAND_SIG(move_left_alpha_numeric_boundary)
CUSTOM_DOC("Seek left for boundary between alphanumeric characters and non-alphanumeric characters.")
{
    Scratch_Block scratch(app);
    current_view_scan_move(app, Scan_Backward, push_boundary_list(scratch, boundary_alpha_numeric));
}

CUSTOM_COMMAND_SIG(move_right_alpha_numeric_or_camel_boundary)
CUSTOM_DOC("Seek right for boundary between alphanumeric characters or camel case word and non-alphanumeric characters.")
{
    Scratch_Block scratch(app);
    current_view_scan_move(app, Scan_Forward, push_boundary_list(scratch, boundary_alpha_numeric_camel));
}

CUSTOM_COMMAND_SIG(move_left_alpha_numeric_or_camel_boundary)
CUSTOM_DOC("Seek left for boundary between alphanumeric characters or camel case word and non-alphanumeric characters.")
{
    Scratch_Block scratch(app);
    current_view_scan_move(app, Scan_Backward, push_boundary_list(scratch, boundary_alpha_numeric_camel));
}

////////////////////////////////

CUSTOM_COMMAND_SIG(select_all)
CUSTOM_DOC("Puts the cursor at the top of the file, and the mark at the bottom of the file.")
{
    View_ID view = get_active_view(app, Access_ReadVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadVisible);
    i32 buffer_size = (i32)buffer_get_size(app, buffer);
    view_set_cursor_and_preferred_x(app, view, seek_pos(0));
    view_set_mark(app, view, seek_pos(buffer_size));
    no_mark_snap_to_cursor(app, view);
}

////////////////////////////////

CUSTOM_COMMAND_SIG(to_uppercase)
CUSTOM_DOC("Converts all ascii text in the range between the cursor and the mark to uppercase.")
{
    View_ID view = get_active_view(app, Access_ReadWriteVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadWriteVisible);
    Range_i64 range = get_view_range(app, view);
    Scratch_Block scratch(app);
    String_Const_u8 string = push_buffer_range(app, scratch, buffer, range);
    string = string_mod_upper(string);
    buffer_replace_range(app, buffer, range, string);
    view_set_cursor_and_preferred_x(app, view, seek_pos(range.max));
}

CUSTOM_COMMAND_SIG(to_lowercase)
CUSTOM_DOC("Converts all ascii text in the range between the cursor and the mark to lowercase.")
{
    View_ID view = get_active_view(app, Access_ReadWriteVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadWriteVisible);
    Range_i64 range = get_view_range(app, view);
    Scratch_Block scratch(app);
    String_Const_u8 string = push_buffer_range(app, scratch, buffer, range);
    string = string_mod_lower(string);
    buffer_replace_range(app, buffer, range, string);
    view_set_cursor_and_preferred_x(app, view, seek_pos(range.max));
}

function void
clean_all_lines_buffer(Application_Links *app, Buffer_ID buffer){
    ProfileScope(app, "clean all lines");
    Scratch_Block scratch(app);
    Batch_Edit *batch_first = 0;
    Batch_Edit *batch_last = 0;
    
    i64 line_count = buffer_get_line_count(app, buffer);
    for (i64 line_number = 1; line_number <= line_count; line_number += 1){
        i64 line_start = get_line_side_pos(app, buffer, line_number, Side_Min);
        i64 line_end = get_line_side_pos(app, buffer, line_number, Side_Max);
        u8 prev = buffer_get_char(app, buffer, line_end - 1);
        b32 has_cr_character = false;
        b32 has_tail_whitespace = false;
        if (prev == '\r'){
            has_cr_character = true;
            if (line_end - 2 >= line_start){
                prev = buffer_get_char(app, buffer, line_end - 2);
                has_tail_whitespace = character_is_whitespace(prev);
            }
        }
        else{
            has_tail_whitespace = character_is_whitespace(prev);
        }
        if (has_tail_whitespace){
            String_Const_u8 line = push_buffer_range(app, scratch, buffer,
                                                     Ii64(line_start, line_end));
            if (line.size > 0){
                i64 end_offset = line.size;
                i64 i = line.size - 1;
                if (has_cr_character){
                    end_offset -= 1;
                    i -= 1;
                }
                i64 start_offset = 0;
                for (; i >= 0; i -= 1){
                    if (!character_is_whitespace(line.str[i])){
                        start_offset = i + 1;
                        break;
                    }
                }
                
                if (start_offset > 0){
                    i64 start = start_offset + line_start;
                    i64 end   = end_offset   + line_start;
                    
                    Batch_Edit *batch = push_array(scratch, Batch_Edit, 1);
                    sll_queue_push(batch_first, batch_last, batch);
                    batch->edit.text = SCu8();
                    batch->edit.range = Ii64(start, end);
                }
            }
        }
    }
    
    if (batch_first != 0){
        buffer_batch_edit(app, buffer, batch_first);
    }
}

CUSTOM_COMMAND_SIG(clean_all_lines)
CUSTOM_DOC("Removes trailing whitespace from all lines in the current buffer.")
{
    ProfileScope(app, "clean all lines");
    View_ID view = get_active_view(app, Access_ReadWriteVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadWriteVisible);
    clean_all_lines_buffer(app, buffer);
}

////////////////////////////////

CUSTOM_COMMAND_SIG(basic_change_active_panel)
CUSTOM_DOC("Change the currently active panel, moving to the panel with the next highest view_id.  Will not skipe the build panel if it is open.")
{
    View_ID view = get_active_view(app, Access_Always);
    get_next_view_looped_all_panels(app, view, Access_Always);
    view_set_active(app, view);
}

CUSTOM_COMMAND_SIG(close_panel)
CUSTOM_DOC("Closes the currently active panel if it is not the only panel open.")
{
    View_ID view = get_active_view(app, Access_Always);
    view_close(app, view);
}

////////////////////////////////

CUSTOM_COMMAND_SIG(show_scrollbar)
CUSTOM_DOC("Sets the current view to show it's scrollbar.")
{
    View_ID view = get_active_view(app, Access_Always);
    view_set_setting(app, view, ViewSetting_ShowScrollbar, true);
}

CUSTOM_COMMAND_SIG(hide_scrollbar)
CUSTOM_DOC("Sets the current view to hide it's scrollbar.")
{
    View_ID view = get_active_view(app, Access_Always);
    view_set_setting(app, view, ViewSetting_ShowScrollbar, false);
}

CUSTOM_COMMAND_SIG(show_filebar)
CUSTOM_DOC("Sets the current view to show it's filebar.")
{
    View_ID view = get_active_view(app, Access_Always);
    view_set_setting(app, view, ViewSetting_ShowFileBar, true);
}

CUSTOM_COMMAND_SIG(hide_filebar)
CUSTOM_DOC("Sets the current view to hide it's filebar.")
{
    View_ID view = get_active_view(app, Access_Always);
    view_set_setting(app, view, ViewSetting_ShowFileBar, false);
}

CUSTOM_COMMAND_SIG(toggle_filebar)
CUSTOM_DOC("Toggles the visibility status of the current view's filebar.")
{
    View_ID view = get_active_view(app, Access_Always);
    b64 value = false;
    view_get_setting(app, view, ViewSetting_ShowFileBar, &value);
    view_set_setting(app, view, ViewSetting_ShowFileBar, !value);
}

CUSTOM_COMMAND_SIG(toggle_fps_meter)
CUSTOM_DOC("Toggles the visibility of the FPS performance meter")
{
    show_fps_hud = !show_fps_hud;
}

CUSTOM_COMMAND_SIG(set_face_size)
CUSTOM_DOC("Set face size of the face used by the current buffer.")
{
    View_ID view = get_active_view(app, Access_Always);
    Buffer_ID buffer = view_get_buffer(app, view, Access_Always);
    Face_ID face_id = get_face_id(app, buffer);
    Face_Description description = get_face_description(app, face_id);
    
    Query_Bar_Group group(app);
    u8 string_space[256];
    Query_Bar bar = {};
    bar.prompt = string_u8_litexpr("Face Size: ");
    bar.string = SCu8(string_space, (u64)0);
    bar.string_capacity = sizeof(string_space);
    if (query_user_number(app, &bar, description.parameters.pt_size)){
        description.parameters.pt_size = (u32)string_to_integer(bar.string, 10);
        try_modify_face(app, face_id, &description);
    }
}

CUSTOM_COMMAND_SIG(increase_face_size)
CUSTOM_DOC("Increase the size of the face used by the current buffer.")
{
    View_ID view = get_active_view(app, Access_Always);
    Buffer_ID buffer = view_get_buffer(app, view, Access_Always);
    Face_ID face_id = get_face_id(app, buffer);
    Face_Description description = get_face_description(app, face_id);
    ++description.parameters.pt_size;
    try_modify_face(app, face_id, &description);
}

CUSTOM_COMMAND_SIG(decrease_face_size)
CUSTOM_DOC("Decrease the size of the face used by the current buffer.")
{
    View_ID view = get_active_view(app, Access_Always);
    Buffer_ID buffer = view_get_buffer(app, view, Access_Always);
    Face_ID face_id = get_face_id(app, buffer);
    Face_Description description = get_face_description(app, face_id);
    --description.parameters.pt_size;
    try_modify_face(app, face_id, &description);
}

CUSTOM_COMMAND_SIG(set_face_size_this_buffer)
CUSTOM_DOC("Set face size of the face used by the current buffer; if any other buffers are using the same face a new face is created so that only this buffer is effected")
{
    View_ID view = get_active_view(app, Access_Always);
    Buffer_ID buffer = view_get_buffer(app, view, Access_Always);
    Face_ID face_id = get_face_id(app, buffer);
    
    b32 is_shared = false;
    for (Buffer_ID buf_it = get_buffer_next(app, 0, Access_Always);
         buf_it != 0;
         buf_it = get_buffer_next(app, buf_it, Access_Always)){
        if (buf_it == buffer){
            continue;
        }
        Face_ID buf_it_face_id = get_face_id(app, buf_it);
        if (buf_it_face_id == face_id){
            is_shared = true;
        }
    }
    
    if (is_shared){
        Face_Description description = get_face_description(app, face_id);
        face_id = try_create_new_face(app, &description);
        if (face_id != 0){
            buffer_set_face(app, buffer, face_id);
        }
    }
    
    set_face_size(app);
}

CUSTOM_COMMAND_SIG(mouse_wheel_change_face_size)
CUSTOM_DOC("Reads the state of the mouse wheel and uses it to either increase or decrease the face size.")
{
    local_persist u64 next_resize_time = 0;
    u64 now = system_now_time();
    if (now >= next_resize_time){
        next_resize_time = now + 50*1000;
        Mouse_State mouse = get_mouse_state(app);
        if (mouse.wheel > 0){
            decrease_face_size(app);
        }
        else if (mouse.wheel < 0){
            increase_face_size(app);
        }
    }
}

CUSTOM_COMMAND_SIG(toggle_show_whitespace)
CUSTOM_DOC("Toggles the current buffer's whitespace visibility status.")
{
    View_ID view = get_active_view(app, Access_ReadVisible);
    b64 show_whitespace = false;
    view_get_setting(app, view, ViewSetting_ShowWhitespace, &show_whitespace);
    view_set_setting(app, view, ViewSetting_ShowWhitespace, !show_whitespace);
}

CUSTOM_COMMAND_SIG(toggle_line_numbers)
CUSTOM_DOC("Toggles the left margin line numbers.")
{
    global_config.show_line_number_margins = !global_config.show_line_number_margins;
}

CUSTOM_COMMAND_SIG(toggle_line_wrap)
CUSTOM_DOC("Toggles the line wrap setting on this buffer.")
{
    View_ID view = get_active_view(app, Access_ReadVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_Always);
    Managed_Scope scope = buffer_get_managed_scope(app, buffer);
    b32 *wrap_lines_ptr = scope_attachment(app, scope, buffer_wrap_lines, b32);
    if (wrap_lines_ptr != 0){
        *wrap_lines_ptr = !(*wrap_lines_ptr);
        buffer_clear_layout_cache(app, buffer);
    }
}

CUSTOM_COMMAND_SIG(exit_4coder)
CUSTOM_DOC("Attempts to close 4coder.")
{
    send_exit_signal(app);
}

////////////////////////////////

CUSTOM_COMMAND_SIG(goto_line)
CUSTOM_DOC("Queries the user for a number, and jumps the cursor to the corresponding line.")
{
    Query_Bar_Group group(app);
    u8 string_space[256];
    Query_Bar bar = {};
    bar.prompt = string_u8_litexpr("Goto Line: ");
    bar.string = SCu8(string_space, (u64)0);
    bar.string_capacity = sizeof(string_space);
    if (query_user_number(app, &bar)){
        i32 line_number = (i32)string_to_integer(bar.string, 10);
        View_ID view = get_active_view(app, Access_ReadVisible);
        view_set_cursor_and_preferred_x(app, view, seek_line_col(line_number, 0));
    }
}

CUSTOM_COMMAND_SIG(search);
CUSTOM_COMMAND_SIG(reverse_search);

function void
isearch__update_highlight(Application_Links *app, View_ID view, Range_i64 range){
    view_set_highlight_range(app, view, range);
    view_set_cursor_and_preferred_x(app, view, seek_pos(range.start));
}

function void
isearch(Application_Links *app, Scan_Direction start_scan, i64 first_pos,
        String_Const_u8 query_init){
    View_ID view = get_active_view(app, Access_ReadVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadVisible);
    if (!buffer_exists(app, buffer)){
        return;
    }
    
    i64 buffer_size = buffer_get_size(app, buffer);
    
    Query_Bar_Group group(app);
    Query_Bar bar = {};
    if (start_query_bar(app, &bar, 0) == 0){
        return;
    }
    
    Scan_Direction scan = start_scan;
    i64 pos = first_pos;
    
    u8 bar_string_space[256];
    bar.string = SCu8(bar_string_space, query_init.size);
    block_copy(bar.string.str, query_init.str, query_init.size);
    
    String_Const_u8 isearch_str = string_u8_litexpr("I-Search: ");
    String_Const_u8 rsearch_str = string_u8_litexpr("Reverse-I-Search: ");
    
    u64 match_size = bar.string.size;
    
    User_Input in = {};
    for (;;){
        switch (scan){
            case Scan_Forward:
            {
                bar.prompt = isearch_str;
            }break;
            case Scan_Backward:
            {
                bar.prompt = rsearch_str;
            }break;
        }
        isearch__update_highlight(app, view, Ii64_size(pos, match_size));
        
        in = get_next_input(app, EventPropertyGroup_Any, EventProperty_Escape);
        if (in.abort){
            break;
        }
        
        String_Const_u8 string = to_writable(&in);
        
        b32 string_change = false;
        if (match_key_code(&in, KeyCode_Return) ||
            match_key_code(&in, KeyCode_Tab)){
            Input_Modifier_Set *mods = &in.event.key.modifiers;
            if (has_modifier(mods, KeyCode_Control)){
                bar.string.size = cstring_length(previous_isearch_query);
                block_copy(bar.string.str, previous_isearch_query, bar.string.size);
            }
            else{
                u64 size = bar.string.size;
                size = clamp_top(size, sizeof(previous_isearch_query) - 1);
                block_copy(previous_isearch_query, bar.string.str, size);
                previous_isearch_query[size] = 0;
                break;
            }
        }
        else if (string.str != 0 && string.size > 0){
            String_u8 bar_string = Su8(bar.string, sizeof(bar_string_space));
            string_append(&bar_string, string);
            bar.string = bar_string.string;
            string_change = true;
        }
        else if (match_key_code(&in, KeyCode_Backspace)){
            if (is_unmodified_key(&in.event)){
                u64 old_bar_string_size = bar.string.size;
                bar.string = backspace_utf8(bar.string);
                string_change = (bar.string.size < old_bar_string_size);
            }
            else if (has_modifier(&in.event.key.modifiers, KeyCode_Control)){
                if (bar.string.size > 0){
                    string_change = true;
                    bar.string.size = 0;
                }
            }
        }
        
        b32 do_scan_action = false;
        b32 do_scroll_wheel = false;
        Scan_Direction change_scan = scan;
        if (!string_change){
            if (match_key_code(&in, KeyCode_PageDown) ||
                match_key_code(&in, KeyCode_Down)){
                change_scan = Scan_Forward;
                do_scan_action = true;
            }
            else if (match_key_code(&in, KeyCode_PageUp) ||
                     match_key_code(&in, KeyCode_Up)){
                change_scan = Scan_Backward;
                do_scan_action = true;
            }
            else{
                // NOTE(allen): is the user trying to execute another command?
                View_Context ctx = view_current_context(app, view);
                Mapping *mapping = ctx.mapping;
                Command_Map *map = mapping_get_map(mapping, ctx.map_id);
                Command_Binding binding = map_get_binding_recursive(mapping, map, &in.event);
                if (binding.custom != 0){
                    if (binding.custom == search){
                        change_scan = Scan_Forward;
                        do_scan_action = true;
                    }
                    else if (binding.custom == reverse_search){
                        change_scan = Scan_Backward;
                        do_scan_action = true;
                    }
                    else{
                        Command_Metadata *metadata = get_command_metadata(binding.custom);
                        if (metadata != 0){
                            if (metadata->is_ui){
                                view_enqueue_command_function(app, view, binding.custom);
                                break;
                            }
                        }
                        binding.custom(app);
                    }
                }
                else{
                    leave_current_input_unhandled(app);
                }
            }
        }
        
        if (string_change){
            switch (scan){
                case Scan_Forward:
                {
                    i64 new_pos = 0;
                    seek_string_insensitive_forward(app, buffer, pos - 1, 0, bar.string, &new_pos);
                    if (new_pos < buffer_size){
                        pos = new_pos;
                        match_size = bar.string.size;
                    }
                }break;
                
                case Scan_Backward:
                {
                    i64 new_pos = 0;
                    seek_string_insensitive_backward(app, buffer, pos + 1, 0, bar.string, &new_pos);
                    if (new_pos >= 0){
                        pos = new_pos;
                        match_size = bar.string.size;
                    }
                }break;
            }
        }
        else if (do_scan_action){
            scan = change_scan;
            switch (scan){
                case Scan_Forward:
                {
                    i64 new_pos = 0;
                    seek_string_insensitive_forward(app, buffer, pos, 0, bar.string, &new_pos);
                    if (new_pos < buffer_size){
                        pos = new_pos;
                        match_size = bar.string.size;
                    }
                }break;
                
                case Scan_Backward:
                {
                    i64 new_pos = 0;
                    seek_string_insensitive_backward(app, buffer, pos, 0, bar.string, &new_pos);
                    if (new_pos >= 0){
                        pos = new_pos;
                        match_size = bar.string.size;
                    }
                }break;
            }
        }
        else if (do_scroll_wheel){
            mouse_wheel_scroll(app);
        }
    }
    
    view_disable_highlight_range(app, view);
    
    if (in.abort){
        u64 size = bar.string.size;
        size = clamp_top(size, sizeof(previous_isearch_query) - 1);
        block_copy(previous_isearch_query, bar.string.str, size);
        previous_isearch_query[size] = 0;
        view_set_cursor_and_preferred_x(app, view, seek_pos(first_pos));
    }
}

function void
isearch(Application_Links *app, Scan_Direction start_scan, String_Const_u8 query_init){
    View_ID view = get_active_view(app, Access_ReadVisible);
    i64 pos = view_get_cursor_pos(app, view);;
    isearch(app, start_scan, pos, query_init);
}

function void
isearch(Application_Links *app, Scan_Direction start_scan){
    View_ID view = get_active_view(app, Access_ReadVisible);
    i64 pos = view_get_cursor_pos(app, view);;
    isearch(app, start_scan, pos, SCu8());
}

function void
isearch_identifier(Application_Links *app, Scan_Direction scan){
    View_ID view = get_active_view(app, Access_ReadVisible);
    Buffer_ID buffer_id = view_get_buffer(app, view, Access_ReadVisible);
    i64 pos = view_get_cursor_pos(app, view);
    Scratch_Block scratch(app);
    Range_i64 range = enclose_pos_alpha_numeric_underscore(app, buffer_id, pos);
    String_Const_u8 query = push_buffer_range(app, scratch, buffer_id, range);
    isearch(app, scan, range.first, query);
}

CUSTOM_COMMAND_SIG(search)
CUSTOM_DOC("Begins an incremental search down through the current buffer for a user specified string.")
{
    isearch(app, Scan_Forward);
}

CUSTOM_COMMAND_SIG(reverse_search)
CUSTOM_DOC("Begins an incremental search up through the current buffer for a user specified string.")
{
    isearch(app, Scan_Backward);
}

CUSTOM_COMMAND_SIG(search_identifier)
CUSTOM_DOC("Begins an incremental search down through the current buffer for the word or token under the cursor.")
{
    isearch_identifier(app, Scan_Forward);
}

CUSTOM_COMMAND_SIG(reverse_search_identifier)
CUSTOM_DOC("Begins an incremental search up through the current buffer for the word or token under the cursor.")
{
    isearch_identifier(app, Scan_Backward);
}

struct String_Pair{
    b32 valid;
    String_Const_u8 a;
    String_Const_u8 b;
};

internal String_Pair
query_user_replace_pair(Application_Links *app, Arena *arena){
    Query_Bar *replace = push_array(arena, Query_Bar, 1);
    u8 *replace_space = push_array(arena, u8, KB(1));
    replace->prompt = string_u8_litexpr("Replace: ");
    replace->string = SCu8(replace_space, (u64)0);
    replace->string_capacity = KB(1);
    
    Query_Bar *with = push_array(arena, Query_Bar, 1);
    u8 *with_space = push_array(arena, u8, KB(1));
    with->prompt = string_u8_litexpr("With: ");
    with->string = SCu8(with_space, (u64)0);
    with->string_capacity = KB(1);
    
    String_Pair result = {};
    if (query_user_string(app, replace) && replace->string.size != 0 && query_user_string(app, with)){
        result.valid = true;
        result.a = replace->string;
        result.b = with->string;
    }
    return(result);
}

// NOTE(allen): This is a bit of a hacky setup because of Query_Bar lifetimes.  This must be
// called as the last operation of a command.
internal void
replace_in_range_query_user(Application_Links *app, Buffer_ID buffer, Range_i64 range){
    Scratch_Block scratch(app);
    Query_Bar_Group group(app);
    String_Pair pair = query_user_replace_pair(app, scratch);
    if (pair.valid){
        replace_in_range(app, buffer, range, pair.a, pair.b);
    }
}

CUSTOM_COMMAND_SIG(replace_in_range)
CUSTOM_DOC("Queries the user for a needle and string. Replaces all occurences of needle with string in the range between cursor and the mark in the active buffer.")
{
    View_ID view = get_active_view(app, Access_ReadWriteVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadWriteVisible);
    Range_i64 range = get_view_range(app, view);
    replace_in_range_query_user(app, buffer, range);
}

CUSTOM_COMMAND_SIG(replace_in_buffer)
CUSTOM_DOC("Queries the user for a needle and string. Replaces all occurences of needle with string in the active buffer.")
{
    View_ID view = get_active_view(app, Access_ReadWriteVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadWriteVisible);
    Range_i64 range = buffer_range(app, buffer);
    replace_in_range_query_user(app, buffer, range);
}

CUSTOM_COMMAND_SIG(replace_in_all_buffers)
CUSTOM_DOC("Queries the user for a needle and string. Replaces all occurences of needle with string in all editable buffers.")
{
    global_history_edit_group_begin(app);
    
    Scratch_Block scratch(app);
    Query_Bar_Group group(app);
    String_Pair pair = query_user_replace_pair(app, scratch);
    for (Buffer_ID buffer = get_buffer_next(app, 0, Access_ReadWriteVisible);
         buffer != 0;
         buffer = get_buffer_next(app, buffer, Access_ReadWriteVisible)){
        Range_i64 range = buffer_range(app, buffer);
        replace_in_range(app, buffer, range, pair.a, pair.b);
    }
    
    global_history_edit_group_end(app);
}

function void
query_replace_base(Application_Links *app, View_ID view, Buffer_ID buffer_id, i64 pos, String_Const_u8 r, String_Const_u8 w){
    i64 new_pos = 0;
    seek_string_forward(app, buffer_id, pos - 1, 0, r, &new_pos);
    
    User_Input in = {};
    for (;;){
        Range_i64 match = Ii64(new_pos, new_pos + r.size);
        isearch__update_highlight(app, view, match);
        
        in = get_next_input(app, EventProperty_AnyKey, EventProperty_MouseButton);
        if (in.abort || match_key_code(&in, KeyCode_Escape) || !is_unmodified_key(&in.event)){
            break;
        }
        
        i64 size = buffer_get_size(app, buffer_id);
        if (match.max <= size &&
            (match_key_code(&in, KeyCode_Y) ||
             match_key_code(&in, KeyCode_Return) ||
             match_key_code(&in, KeyCode_Tab))){
            buffer_replace_range(app, buffer_id, match, w);
            pos = match.start + w.size;
        }
        else{
            pos = match.max;
        }
        
        seek_string_forward(app, buffer_id, pos, 0, r, &new_pos);
    }
    
    view_disable_highlight_range(app, view);
    
    if (in.abort){
        return;
    }
    
    view_set_cursor_and_preferred_x(app, view, seek_pos(pos));
}

function void
query_replace_parameter(Application_Links *app, String_Const_u8 replace_str, i64 start_pos, b32 add_replace_query_bar){
    Query_Bar_Group group(app);
    Query_Bar replace = {};
    replace.prompt = string_u8_litexpr("Replace: ");
    replace.string = replace_str;
    
    if (add_replace_query_bar){
        start_query_bar(app, &replace, 0);
    }
    
    Query_Bar with = {};
    u8 with_space[1024];
    with.prompt = string_u8_litexpr("With: ");
    with.string = SCu8(with_space, (u64)0);
    with.string_capacity = sizeof(with_space);
    
    if (query_user_string(app, &with)){
        String_Const_u8 r = replace.string;
        String_Const_u8 w = with.string;
        
        View_ID view = get_active_view(app, Access_ReadVisible);
        Buffer_ID buffer = view_get_buffer(app, view, Access_ReadVisible);
        i64 pos = start_pos;
        
        Query_Bar bar = {};
        bar.prompt = string_u8_litexpr("Replace? (y)es, (n)ext, (esc)\n");
        start_query_bar(app, &bar, 0);
        
        query_replace_base(app, view, buffer, pos, r, w);
    }
}

CUSTOM_COMMAND_SIG(query_replace)
CUSTOM_DOC("Queries the user for two strings, and incrementally replaces every occurence of the first string with the second string.")
{
    View_ID view = get_active_view(app, Access_ReadWriteVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadWriteVisible);
    if (buffer != 0){
        Query_Bar_Group group(app);
        Query_Bar replace = {};
        u8 replace_space[1024];
        replace.prompt = string_u8_litexpr("Replace: ");
        replace.string = SCu8(replace_space, (u64)0);
        replace.string_capacity = sizeof(replace_space);
        if (query_user_string(app, &replace)){
            if (replace.string.size > 0){
                i64 pos = view_get_cursor_pos(app, view);
                query_replace_parameter(app, replace.string, pos, false);
            }
        }
    }
}

CUSTOM_COMMAND_SIG(query_replace_identifier)
CUSTOM_DOC("Queries the user for a string, and incrementally replace every occurence of the word or token found at the cursor with the specified string.")
{
    View_ID view = get_active_view(app, Access_ReadWriteVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadWriteVisible);
    if (buffer != 0){
        Scratch_Block scratch(app);
        i64 pos = view_get_cursor_pos(app, view);
        Range_i64 range = enclose_pos_alpha_numeric_underscore(app, buffer, pos);
        String_Const_u8 replace = push_buffer_range(app, scratch, buffer, range);
        if (replace.size != 0){
            query_replace_parameter(app, replace, range.min, true);
        }
    }
}

CUSTOM_COMMAND_SIG(query_replace_selection)
CUSTOM_DOC("Queries the user for a string, and incrementally replace every occurence of the string found in the selected range with the specified string.")
{
    View_ID view = get_active_view(app, Access_ReadWriteVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadWriteVisible);
    if (buffer != 0){
        Scratch_Block scratch(app);
        Range_i64 range = get_view_range(app, view);
        String_Const_u8 replace = push_buffer_range(app, scratch, buffer, range);
        if (replace.size != 0){
            query_replace_parameter(app, replace, range.min, true);
        }
    }
}

////////////////////////////////

function void
delete_file_base(Application_Links *app, String_Const_u8 file_name, Buffer_ID buffer_id){
    String_Const_u8 path = string_remove_last_folder(file_name);
    Scratch_Block scratch(app);
    List_String_Const_u8 list = {};
#if OS_WINDOWS
    string_list_push_u8_lit(scratch, &list, "del ");
#elif OS_LINUX || OS_MAC
    string_list_push_u8_lit(scratch, &list, "rm ");
#else
# error no delete file command for this platform
#endif
    string_list_pushf(scratch, &list, "\"%.*s\"", string_expand(file_name));
    String_Const_u8 cmd = string_list_flatten(scratch, list, StringFill_NullTerminate);
    exec_system_command(app, 0, buffer_identifier(0), path, cmd, 0);
    buffer_kill(app, buffer_id, BufferKill_AlwaysKill);
}

CUSTOM_COMMAND_SIG(delete_file_query)
CUSTOM_DOC("Deletes the file of the current buffer if 4coder has the appropriate access rights. Will ask the user for confirmation first.")
{
    View_ID view = get_active_view(app, Access_Always);
    Buffer_ID buffer = view_get_buffer(app, view, Access_Always);
    Scratch_Block scratch(app);
    String_Const_u8 file_name = push_buffer_file_name(app, scratch, buffer);
    if (file_name.size > 0){
        Query_Bar_Group group(app);
        Query_Bar bar = {};
        bar.prompt = push_u8_stringf(scratch, "Delete '%.*s' (Y)es, (n)o", string_expand(file_name));
        if (start_query_bar(app, &bar, 0) != 0){
            b32 cancelled = false;
            for (;!cancelled;){
                User_Input in = get_next_input(app, EventProperty_AnyKey, 0);
                if (in.abort){
                    cancelled = true;
                }
                else{
                    switch (in.event.key.code){
                        case KeyCode_Y:
                        {
                            delete_file_base(app, file_name, buffer);
                            cancelled = true;
                        }break;
                        
                        case KeyCode_Shift:
                        case KeyCode_Control:
                        case KeyCode_Alt:
                        case KeyCode_Command:
                        case KeyCode_CapsLock:
                        {}break;
                        
                        default:
                        {
                            cancelled = true;
                        }break;
                    }
                }
            }
        }
    }
}

CUSTOM_COMMAND_SIG(save_to_query)
CUSTOM_DOC("Queries the user for a file name and saves the contents of the current buffer, altering the buffer's name too.")
{
    View_ID view = get_active_view(app, Access_Always);
    Buffer_ID buffer = view_get_buffer(app, view, Access_Always);
    
    Scratch_Block scratch(app);
    Query_Bar_Group group(app);
    String_Const_u8 buffer_name = push_buffer_unique_name(app, scratch, buffer);
    
    // Query the user
    u8 name_space[4096];
    Query_Bar bar = {};
    bar.prompt = push_u8_stringf(scratch, "Save '%.*s' to: ", string_expand(buffer_name));
    bar.string = SCu8(name_space, (u64)0);
    bar.string_capacity = sizeof(name_space);
    if (query_user_string(app, &bar)){
        if (bar.string.size != 0){
            List_String_Const_u8 new_file_name_list = {};
            string_list_push(scratch, &new_file_name_list, push_hot_directory(app, scratch));
            string_list_push(scratch, &new_file_name_list, bar.string);
            String_Const_u8 new_file_name = string_list_flatten(scratch, new_file_name_list);
            if (buffer_save(app, buffer, new_file_name, BufferSave_IgnoreDirtyFlag)){
                Buffer_ID new_buffer = create_buffer(app, new_file_name, BufferCreate_NeverNew|BufferCreate_JustChangedFile);
                if (new_buffer != 0 && new_buffer != buffer){
                    buffer_kill(app, buffer, BufferKill_AlwaysKill);
                    view_set_buffer(app, view, new_buffer, 0);
                }
            }
        }
    }
}

CUSTOM_COMMAND_SIG(rename_file_query)
CUSTOM_DOC("Queries the user for a new name and renames the file of the current buffer, altering the buffer's name too.")
{
    View_ID view = get_active_view(app, Access_Always);
    Buffer_ID buffer = view_get_buffer(app, view, Access_Always);
    
    Scratch_Block scratch(app);
    
    String_Const_u8 file_name = push_buffer_file_name(app, scratch, buffer);
    if (file_name.size > 0){
        // Query the user
        Query_Bar_Group group(app);
        String_Const_u8 front = string_front_of_path(file_name);
        u8 name_space[4096];
        Query_Bar bar = {};
        bar.prompt = push_u8_stringf(scratch, "Rename '%.*s' to: ", string_expand(front));
        bar.string = SCu8(name_space, (u64)0);
        bar.string_capacity = sizeof(name_space);
        if (query_user_string(app, &bar) && bar.string.size != 0){
            // TODO(allen): There should be a way to say, "detach a buffer's file" and "attach this file to a buffer"
            List_String_Const_u8 new_file_name_list = {};
            string_list_push(scratch, &new_file_name_list, string_remove_front_of_path(file_name));
            string_list_push(scratch, &new_file_name_list, bar.string);
            String_Const_u8 new_file_name = string_list_flatten(scratch, new_file_name_list, StringFill_NullTerminate);
            if (buffer_save(app, buffer, new_file_name, BufferSave_IgnoreDirtyFlag)){
                Buffer_ID new_buffer = create_buffer(app, new_file_name, BufferCreate_NeverNew|BufferCreate_JustChangedFile);
                if (new_buffer != 0 && new_buffer != buffer){
                    delete_file_base(app, file_name, buffer);
                    view_set_buffer(app, view, new_buffer, 0);
                }
            }
        }
    }
}

CUSTOM_COMMAND_SIG(make_directory_query)
CUSTOM_DOC("Queries the user for a name and creates a new directory with the given name.")
{
    Scratch_Block scratch(app);
    
    String_Const_u8 hot = push_hot_directory(app, scratch);
    
    // Query the user
    Query_Bar_Group group(app);
    u8 name_space[4096];
    Query_Bar bar = {};
    bar.prompt = push_u8_stringf(scratch, "Make directory at '%.*s': ", string_expand(hot));
    bar.string = SCu8(name_space, (u64)0);
    bar.string_capacity = sizeof(name_space);
    
    if (!query_user_string(app, &bar)) return;
    if (bar.string.size == 0) return;
    
    String_Const_u8 cmd = push_u8_stringf(scratch, "mkdir %.*s", string_expand(bar.string));
    exec_system_command(app, 0, buffer_identifier(0), hot, cmd, 0);
}

////////////////////////////////

internal void
current_view_move_line(Application_Links *app, Scan_Direction direction){
    View_ID view = get_active_view(app, Access_ReadWriteVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadWriteVisible);
    i64 pos = view_get_cursor_pos(app, view);
    i64 line_number = get_line_number_from_pos(app, buffer, pos);
    pos = move_line(app, buffer, line_number, direction);
    view_set_cursor_and_preferred_x(app, view, seek_pos(pos));
}

CUSTOM_COMMAND_SIG(move_line_up)
CUSTOM_DOC("Swaps the line under the cursor with the line above it, and moves the cursor up with it.")
{
    current_view_move_line(app, Scan_Backward);
}

CUSTOM_COMMAND_SIG(move_line_down)
CUSTOM_DOC("Swaps the line under the cursor with the line below it, and moves the cursor down with it.")
{
    current_view_move_line(app, Scan_Forward);
}

CUSTOM_COMMAND_SIG(duplicate_line)
CUSTOM_DOC("Create a copy of the line on which the cursor sits.")
{
    View_ID view = get_active_view(app, Access_ReadWriteVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadWriteVisible);
    i64 pos = view_get_cursor_pos(app, view);
    i64 line = get_line_number_from_pos(app, buffer, pos);
    Scratch_Block scratch(app);
    String_Const_u8 s = push_buffer_line(app, scratch, buffer, line);
    s = push_u8_stringf(scratch, "%.*s\n", string_expand(s));
    pos = get_line_side_pos(app, buffer, line, Side_Min);
    buffer_replace_range(app, buffer, Ii64(pos), s);
}

CUSTOM_COMMAND_SIG(delete_line)
CUSTOM_DOC("Delete the line the on which the cursor sits.")
{
    View_ID view = get_active_view(app, Access_ReadWriteVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadWriteVisible);
    i64 pos = view_get_cursor_pos(app, view);
    i64 line = get_line_number_from_pos(app, buffer, pos);
    Range_i64 range = get_line_pos_range(app, buffer, line);
    range.end += 1;
    i32 size = (i32)buffer_get_size(app, buffer);
    range.end = clamp_top(range.end, size);
    if (range_size(range) == 0 ||
        buffer_get_char(app, buffer, range.end - 1) != '\n'){
        range.start -= 1;
        range.first = clamp_bot(0, range.first);
    }
    buffer_replace_range(app, buffer, range, string_u8_litexpr(""));
}

////////////////////////////////

function b32
get_cpp_matching_file(Application_Links *app, Buffer_ID buffer, Buffer_ID *buffer_out){
    b32 result = false;
    Scratch_Block scratch(app);
    String_Const_u8 file_name = push_buffer_file_name(app, scratch, buffer);
    if (file_name.size > 0){
        String_Const_u8 extension = string_file_extension(file_name);
        String_Const_u8 new_extensions[2] = {};
        i32 new_extensions_count = 0;
        if (string_match(extension, string_u8_litexpr("cpp")) || string_match(extension, string_u8_litexpr("cc"))){
            new_extensions[0] = string_u8_litexpr("h");
            new_extensions[1] = string_u8_litexpr("hpp");
            new_extensions_count = 2;
        }
        else if (string_match(extension, string_u8_litexpr("c"))){
            new_extensions[0] = string_u8_litexpr("h");
            new_extensions_count = 1;
        }
        else if (string_match(extension, string_u8_litexpr("h"))){
            new_extensions[0] = string_u8_litexpr("c");
            new_extensions[1] = string_u8_litexpr("cpp");
            new_extensions_count = 2;
        }
        else if (string_match(extension, string_u8_litexpr("hpp"))){
            new_extensions[0] = string_u8_litexpr("cpp");
            new_extensions_count = 1;
        }
        
        String_Const_u8 file_without_extension = string_file_without_extension(file_name);
        for (i32 i = 0; i < new_extensions_count; i += 1){
            Temp_Memory temp = begin_temp(scratch);
            String_Const_u8 new_extension = new_extensions[i];
            String_Const_u8 new_file_name = push_u8_stringf(scratch, "%.*s.%.*s", string_expand(file_without_extension), string_expand(new_extension));
            if (open_file(app, buffer_out, new_file_name, false, true)){
                result = true;
                break;
            }
            end_temp(temp);
        }
    }
    
    return(result);
}

CUSTOM_COMMAND_SIG(open_file_in_quotes)
CUSTOM_DOC("Reads a filename from surrounding '\"' characters and attempts to open the corresponding file.")
{
    View_ID view = get_active_view(app, Access_ReadVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadVisible);
    if (buffer_exists(app, buffer)){
        Scratch_Block scratch(app);
        
        i64 pos = view_get_cursor_pos(app, view);
        
        Range_i64 range = enclose_pos_inside_quotes(app, buffer, pos);
        
        String_Const_u8 quoted_name = push_buffer_range(app, scratch, buffer, range);
        
        String_Const_u8 file_name = push_buffer_file_name(app, scratch, buffer);
        String_Const_u8 path = string_remove_last_folder(file_name);
        
        if (character_is_slash(string_get_character(path, path.size - 1))){
            path = string_chop(path, 1);
        }
        
        String_Const_u8 new_file_name = push_u8_stringf(scratch, "%.*s/%.*s", string_expand(path), string_expand(quoted_name));
        
        view = get_next_view_looped_primary_panels(app, view, Access_Always);
        if (view != 0){
            if (view_open_file(app, view, new_file_name, true)){
                view_set_active(app, view);
            }
        }
    }
}

CUSTOM_COMMAND_SIG(open_matching_file_cpp)
CUSTOM_DOC("If the current file is a *.cpp or *.h, attempts to open the corresponding *.h or *.cpp file in the other view.")
{
    View_ID view = get_active_view(app, Access_Always);
    Buffer_ID buffer = view_get_buffer(app, view, Access_Always);
    Buffer_ID new_buffer = 0;
    if (get_cpp_matching_file(app, buffer, &new_buffer)){
        view = get_next_view_looped_primary_panels(app, view, Access_Always);
        view_set_buffer(app, view, new_buffer, 0);
        view_set_active(app, view);
    }
}

CUSTOM_COMMAND_SIG(view_buffer_other_panel)
CUSTOM_DOC("Set the other non-active panel to view the buffer that the active panel views, and switch to that panel.")
{
    View_ID view = get_active_view(app, Access_Always);
    Buffer_ID buffer = view_get_buffer(app, view, Access_Always);
    i64 pos = view_get_cursor_pos(app, view);
    change_active_panel(app);
    view = get_active_view(app, Access_Always);
    view_set_buffer(app, view, buffer, 0);
    view_set_cursor_and_preferred_x(app, view, seek_pos(pos));
}

CUSTOM_COMMAND_SIG(swap_panels)
CUSTOM_DOC("Swaps the active panel with it's sibling.")
{
    View_ID view = get_active_view(app, Access_Always);
    Panel_ID panel = view_get_panel(app, view);
    Panel_ID parent = panel_get_parent(app, panel);
    for (;parent != 0;){
        Panel_ID child_1 = panel_get_child(app, parent, Side_Min);
        Panel_ID child_2 = panel_get_child(app, parent, Side_Max);
        
        View_ID view_1 = panel_get_view(app, child_1, Access_Always);
        View_ID view_2 = panel_get_view(app, child_2, Access_Always);
        
        if (!view_get_is_passive(app, view_1) && !view_get_is_passive(app, view_2)){
            panel_swap_children(app, parent);
            break;
        }
        
        parent = panel_get_parent(app, parent);
    }
}

////////////////////////////////

CUSTOM_COMMAND_SIG(kill_buffer)
CUSTOM_DOC("Kills the current buffer.")
{
    View_ID view = get_active_view(app, Access_ReadVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadVisible);
    try_buffer_kill(app, buffer, view, 0);
}

CUSTOM_COMMAND_SIG(save)
CUSTOM_DOC("Saves the current buffer.")
{
    View_ID view = get_active_view(app, Access_ReadVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadVisible);
    Scratch_Block scratch(app);
    String_Const_u8 file_name = push_buffer_file_name(app, scratch, buffer);
    buffer_save(app, buffer, file_name, 0);
}

CUSTOM_COMMAND_SIG(reopen)
CUSTOM_DOC("Reopen the current buffer from the hard drive.")
{
    View_ID view = get_active_view(app, Access_ReadVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadVisible);
    buffer_reopen(app, buffer, 0);
}

////////////////////////////////

internal i32
record_get_new_cursor_position_undo(Application_Links *app, Buffer_ID buffer_id, History_Record_Index index, Record_Info record){
    i32 new_edit_position = 0;
    switch (record.kind){
        default:
        case RecordKind_Single:
        {
            new_edit_position = (i32)(record.single_first + record.single_string_backward.size);
        }break;
        case RecordKind_Group:
        {
            Record_Info sub_record = buffer_history_get_group_sub_record(app, buffer_id, index, 0);
            new_edit_position = (i32)(sub_record.single_first + sub_record.single_string_backward.size);
        }break;
    }
    return(new_edit_position);
}

internal i32
record_get_new_cursor_position_undo(Application_Links *app, Buffer_ID buffer_id, History_Record_Index index){
    Record_Info record = buffer_history_get_record_info(app, buffer_id, index);
    return(record_get_new_cursor_position_undo(app, buffer_id, index, record));
}

internal i32
record_get_new_cursor_position_redo(Application_Links *app, Buffer_ID buffer_id, History_Record_Index index, Record_Info record){
    i64 new_edit_position = 0;
    switch (record.kind){
        default:
        case RecordKind_Single:
        {
            new_edit_position = record.single_first + record.single_string_forward.size;
        }break;
        case RecordKind_Group:
        {
            Record_Info sub_record = buffer_history_get_group_sub_record(app, buffer_id, index, record.group_count - 1);
            new_edit_position = sub_record.single_first + sub_record.single_string_forward.size;
        }break;
    }
    return((i32)(new_edit_position));
}

internal i32
record_get_new_cursor_position_redo(Application_Links *app, Buffer_ID buffer_id, History_Record_Index index){
    Record_Info record = buffer_history_get_record_info(app, buffer_id, index);
    return(record_get_new_cursor_position_redo(app, buffer_id, index, record));
}

CUSTOM_COMMAND_SIG(undo)
CUSTOM_DOC("Advances backwards through the undo history of the current buffer.")
{
    View_ID view = get_active_view(app, Access_ReadWriteVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadWriteVisible);
    History_Record_Index current = buffer_history_get_current_state_index(app, buffer);
    if (current > 0){
        i32 new_position = record_get_new_cursor_position_undo(app, buffer, current);
        buffer_history_set_current_state_index(app, buffer, current - 1);
        view_set_cursor_and_preferred_x(app, view, seek_pos(new_position));
    }
}

CUSTOM_COMMAND_SIG(redo)
CUSTOM_DOC("Advances forwards through the undo history of the current buffer.")
{
    View_ID view = get_active_view(app, Access_ReadWriteVisible);
    Buffer_ID buffer = view_get_buffer(app, view, Access_ReadWriteVisible);
    History_Record_Index current = buffer_history_get_current_state_index(app, buffer);
    History_Record_Index max_index = buffer_history_get_max_record_index(app, buffer);
    if (current < max_index){
        i32 new_position = record_get_new_cursor_position_redo(app, buffer, current + 1);
        buffer_history_set_current_state_index(app, buffer, current + 1);
        view_set_cursor_and_preferred_x(app, view, seek_pos(new_position));
    }
}

CUSTOM_COMMAND_SIG(undo_all_buffers)
CUSTOM_DOC("Advances backward through the undo history in the buffer containing the most recent regular edit.")
{
    Scratch_Block scratch(app);
    i32 highest_edit_number = -1;
    Buffer_ID first_buffer_match = 0;
    Buffer_ID last_buffer_match = 0;
    i32 match_count = 0;
    
    {
        for (Buffer_ID buffer = get_buffer_next(app, 0, Access_Always);
             buffer != 0;
             buffer = get_buffer_next(app, buffer, Access_Always)){
            History_Record_Index index = buffer_history_get_current_state_index(app, buffer);
            if (index > 0){
                Record_Info record = buffer_history_get_record_info(app, buffer, index);
                if (record.edit_number > highest_edit_number){
                    highest_edit_number = record.edit_number;
                    first_buffer_match = buffer;
                    last_buffer_match = buffer;
                    match_count = 1;
                }
                else if (record.edit_number == highest_edit_number){
                    last_buffer_match = buffer;
                    match_count += 1;
                }
            }
        }
    }
    
    Buffer_ID *match_buffers = push_array(scratch, Buffer_ID, match_count);
    i32 *new_positions = push_array(scratch, i32, match_count);
    match_count = 0;
    
    if (highest_edit_number != -1){
        for (Buffer_ID buffer = first_buffer_match;
             buffer != 0;
             buffer = get_buffer_next(app, buffer, Access_Always)){
            b32 did_match = false;
            i32 new_edit_position = 0;
            for (;;){
                History_Record_Index index = buffer_history_get_current_state_index(app, buffer);
                if (index > 0){
                    Record_Info record = buffer_history_get_record_info(app, buffer, index);
                    if (record.edit_number == highest_edit_number){
                        did_match = true;
                        new_edit_position = record_get_new_cursor_position_undo(app, buffer, index, record);
                        buffer_history_set_current_state_index(app, buffer, index - 1);
                    }
                    else{
                        break;
                    }
                }
                else{
                    break;
                }
            }
            if (did_match){
                match_buffers[match_count] = buffer;
                new_positions[match_count] = new_edit_position;
                match_count += 1;
            }
            if (buffer == last_buffer_match){
                break;
            }
        }
    }
    
    view_buffer_set(app, match_buffers, new_positions, match_count);
}

CUSTOM_COMMAND_SIG(redo_all_buffers)
CUSTOM_DOC("Advances forward through the undo history in the buffer containing the most recent regular edit.")
{
    Scratch_Block scratch(app);
    
    i32 lowest_edit_number = 0x7FFFFFFF;
    Buffer_ID first_buffer_match = 0;
    Buffer_ID last_buffer_match = 0;
    i32 match_count = 0;
    
    {
        for (Buffer_ID buffer = get_buffer_next(app, 0, Access_Always);
             buffer != 0;
             buffer = get_buffer_next(app, buffer, Access_Always)){
            History_Record_Index max_index = buffer_history_get_max_record_index(app, buffer);
            History_Record_Index index = buffer_history_get_current_state_index(app, buffer);
            if (index < max_index){
                Record_Info record = buffer_history_get_record_info(app, buffer, index + 1);
                if (record.edit_number < lowest_edit_number){
                    lowest_edit_number = record.edit_number;
                    first_buffer_match = buffer;
                    last_buffer_match = buffer;
                    match_count = 1;
                }
                else if (record.edit_number == lowest_edit_number){
                    last_buffer_match = buffer;
                    match_count += 1;
                }
            }
        }
    }
    
    Buffer_ID *match_buffers = push_array(scratch, Buffer_ID, match_count);
    i32 *new_positions = push_array(scratch, i32, match_count);
    match_count = 0;
    
    if (lowest_edit_number != -1){
        for (Buffer_ID buffer = first_buffer_match;
             buffer != 0;
             buffer = get_buffer_next(app, buffer, Access_Always)){
            b32 did_match = false;
            i32 new_edit_position = 0;
            History_Record_Index max_index = buffer_history_get_max_record_index(app, buffer);
            for (;;){
                History_Record_Index index = buffer_history_get_current_state_index(app, buffer);
                if (index < max_index){
                    Record_Info record = buffer_history_get_record_info(app, buffer, index + 1);
                    if (record.edit_number == lowest_edit_number){
                        did_match = true;
                        new_edit_position = record_get_new_cursor_position_redo(app, buffer, index + 1, record);
                        buffer_history_set_current_state_index(app, buffer, index + 1);
                    }
                    else{
                        break;
                    }
                }
                else{
                    break;
                }
            }
            if (did_match){
                match_buffers[match_count] = buffer;
                new_positions[match_count] = new_edit_position;
                match_count += 1;
            }
            if (buffer == last_buffer_match){
                break;
            }
        }
    }
    
    view_buffer_set(app, match_buffers, new_positions, match_count);
}

////////////////////////////////

CUSTOM_COMMAND_SIG(open_in_other)
CUSTOM_DOC("Interactively opens a file in the other panel.")
{
    change_active_panel_send_command(app, interactive_open_or_new);
}

CUSTOM_COMMAND_SIG(default_file_externally_modified)
CUSTOM_DOC("Notes the external modification of attached files by printing a message.")
{
    User_Input input = get_current_input(app);
    if (match_core_code(&input, CoreCode_FileExternallyModified)){
        Scratch_Block scratch(app);
        Buffer_ID buffer_id = input.event.core.id;
        String_Const_u8 name = push_buffer_unique_name(app, scratch, buffer_id);
        String_Const_u8 str = push_u8_stringf(scratch, "Modified externally: %s\n", name.str);
        print_message(app, str);
    }
}

// BOTTOM