From 8c69db94621010caa2b417891cae1933cc904bd2 Mon Sep 17 00:00:00 2001
From: Kevin Fischer <kfischer_okarin@yahoo.co.jp>
Date: Sat, 5 Sep 2020 20:22:22 +0900
Subject: Save cursor position in prompt

---
 dragon/console_prompt.rb | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/dragon/console_prompt.rb b/dragon/console_prompt.rb
index aea5df8..2aa1e48 100644
--- a/dragon/console_prompt.rb
+++ b/dragon/console_prompt.rb
@@ -18,23 +18,35 @@ module GTK
         @cursor_color = Color.new [187, 21, 6]
         @console_text_width = console_text_width
 
+        @cursor_position = 0
+
         @last_autocomplete_prefix = nil
         @next_candidate_index = 0
       end
 
+      def current_input_str=(str)
+        @current_input_str = str
+        @cursor_position = str.length
+      end
+
       def <<(str)
-        @current_input_str << str
+        @current_input_str = @current_input_str[0...@cursor_position] + str + @current_input_str[@cursor_position..-1]
+        @cursor_position += str.length
         @current_input_changed_at = Kernel.global_tick_count
         reset_autocomplete
       end
 
       def backspace
-        @current_input_str.chop!
+        return if current_input_str.length.zero? || @cursor_position.zero?
+
+        @current_input_str = @current_input_str[0...(@cursor_position - 1)] + @current_input_str[@cursor_position..-1]
+        @cursor_position -= 1
         reset_autocomplete
       end
 
       def clear
         @current_input_str = ''
+        @cursor_position = 0
         reset_autocomplete
       end
 
-- 
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