Formatting: Trim base indentation off code block content

Author: vedxyz

TabletBot.Discord/Formatting.cs

@@ -1,5 +1,7 @@
 using System;
+using System.Linq;
 using System.Text;
+using System.Text.RegularExpressions;
 using Discord;
 
 namespace TabletBot.Discord
@@ -23,9 +25,24 @@ public static string CodeBlock(string text, string? lang = null) =>
         public static void AppendCodeBlock(this StringBuilder stringBuilder, string[] lines, string? lang = null)
         {
             stringBuilder.AppendLine(CODE_BLOCK + lang);
-            foreach (var line in lines)
+            foreach (var line in TrimBaseIndentation(lines))
                 stringBuilder.AppendLine(line);
             stringBuilder.AppendLine(CODE_BLOCK);
         }
+
+        public static string[] TrimBaseIndentation(string[] lines)
+        {
+            var baseIndentationLength = lines.Min(line => {
+                var indentation = CountIndentation(line);
+                return line.Length > indentation ? indentation : int.MaxValue;
+            });
+
+            for (int i = 0; i != lines.Length; i++)
+                lines[i] = lines[i].Substring(Math.Min(baseIndentationLength, lines[i].Length)).TrimEnd();
+
+            return lines;
+        }
+
+        public static int CountIndentation(string line) => line.TakeWhile(Char.IsWhiteSpace).Count();
     }
 }