Proper fix for #1

tgcli/Util.cs

@@ -9,15 +9,17 @@ using static tgcli.tgcli;
 namespace tgcli {
 	public class Util {
 		public static class Ansi {
-			public const string ResetAll = "\x1B[0m";
+			public const string ResetAll   = "\x1B[0m";
-			public const string Red      = "\x1b[31m";
+			public const string Red        = "\x1b[31m";
-			public const string Green    = "\x1b[32m";
+			public const string Green      = "\x1b[32m";
-			public const string Yellow   = "\x1b[33m";
+			public const string Yellow     = "\x1b[33m";
-			public const string Blue     = "\x1b[34m";
+			public const string Blue       = "\x1b[34m";
-			public const string Magenta  = "\x1b[35m";
+			public const string Magenta    = "\x1b[35m";
-			public const string Cyan     = "\x1b[36m";
+			public const string Cyan       = "\x1b[36m";
-			public const string Bold     = "\x1b[1m";
+			public const string Bold       = "\x1b[1m";
-			public const string BoldOff  = "\x1b[22m";
+			public const string BoldOff    = "\x1b[22m";
+			public const string Inverse    = "\x1b[7m";
+			public const string InverseOff = "\x1b[27m";
 		}
 
 		public static User GetUser(long uid) {
@@ -350,7 +352,10 @@ namespace tgcli {
 			input = input.Replace(Ansi.Magenta, "");
 			input = input.Replace(Ansi.Red, "");
 			input = input.Replace(Ansi.Yellow, "");
+			input = input.Replace(Ansi.Bold, "");
 			input = input.Replace(Ansi.BoldOff, "");
+			input = input.Replace(Ansi.Inverse, "");
+			input = input.Replace(Ansi.InverseOff, "");
 			input = input.Replace(Ansi.ResetAll, "");
 			return input.Length;
 		}
@@ -361,18 +366,46 @@ namespace tgcli {
 			return output + $"{Ansi.ResetAll}]";
 		}
 
-		public static string TruncateString(string input, int maxLen) {
+		public static string TruncateString(string input, int maxLen, string truncateMarker = "~") {
 			if (maxLen < 2)
 				maxLen = 2;
-			return input.Length <= maxLen ? input : input.Substring(0, maxLen - 1) + "~";
+			return input.Length <= maxLen ? input : input.Substring(0, maxLen - 1) + truncateMarker;
 		}
 
-		public static string TruncateMessageStart(string input, int maxLen) {
+		public static (string messageBuffer, int relativeCursorPosition) GetViewIntoMessageBuffer(string message, int absoluteCursorPosition, int bufferWidth) {
-			if (maxLen < 2)
+			const int wraparoundOffsetPre  = 2; // number of "untouchable" characters moving the cursor onto will cause a wrap on the right screen edge
-				maxLen = 2;
+			const int wraparoundOffsetPost = 5; // number of "untouchable" characters moving the cursor onto will cause a wrap on the left screen edge
-			if (input.Contains("⏎ "))
+
-				input = "⏎ " + input.Split("⏎ ").Last();
+			const int wraparoundOffsetPreW  = wraparoundOffsetPre + 1;  // offset + 1 (character on the edge), for easier calculations
-			return input.Length < maxLen ? input : "<" + input.Substring(input.Length - maxLen + 2);
+			const int wraparoundOffsetPostW = wraparoundOffsetPost + 1; // offset + 1 (character on the edge), for easier calculations
+
+			if (absoluteCursorPosition > message.Length)
+				throw new ArgumentOutOfRangeException();
+
+			if (message.Length < bufferWidth)
+				return (message, absoluteCursorPosition);
+
+			if (absoluteCursorPosition < bufferWidth - wraparoundOffsetPre - 1)
+				return (TruncateString(message, bufferWidth, $"{Ansi.Inverse}>{Ansi.InverseOff}"), absoluteCursorPosition);
+
+			// now we can be sure the message needs at least one wrap
+
+			// first wrap
+			// get rid of the content shown on the zeroth wrap, which is buf width minus wraparoundPreW (respects > character on screen edge)
+			var finalMessage   = message[(bufferWidth - wraparoundOffsetPreW - wraparoundOffsetPost)..];
+			var finalCursorPos = absoluteCursorPosition - bufferWidth + wraparoundOffsetPreW + wraparoundOffsetPostW;
+
+			// successive wraps
+			// repeat above steps (but respective of the new < character) until the string fits into the buffer
+			// it fits into the buffer when cursorPos >= bufferwidth minus wraparound (this time respecting > character absent on first wrap)
+			while (finalCursorPos >= bufferWidth - wraparoundOffsetPreW) {
+				finalMessage   = finalMessage[(bufferWidth - wraparoundOffsetPreW - wraparoundOffsetPostW)..];
+				finalCursorPos = finalCursorPos - bufferWidth + wraparoundOffsetPreW + wraparoundOffsetPostW;
+			}
+
+			finalMessage = TruncateString(finalMessage, bufferWidth - 1, $"{Ansi.Inverse}>{Ansi.InverseOff}");
+
+			return ($"{Ansi.Inverse}<{Ansi.InverseOff}" + finalMessage, finalCursorPos);
 		}
 
 		public static readonly List<Tuple<string, string>> Emojis = new() {

tgcli/tgcli.cs

@@ -190,7 +190,8 @@ namespace tgcli {
 					output += "]";
 				output += " > ";
 				var prefixlen = GetActualStringWidth(output);
-				output += TruncateMessageStart(currentInputLine, Console.LargestWindowWidth - GetActualStringWidth(output));
+				var inputLine = GetViewIntoMessageBuffer(currentInputLine, currentInputPos, Console.LargestWindowWidth - prefixlen);
+				output += inputLine.messageBuffer;
 
 				ClearCurrentConsoleLine();
 				messageQueue.ForEach(p => Console.WriteLine(p + Ansi.ResetAll));
@@ -198,7 +199,7 @@ namespace tgcli {
 					Console.Write("\a"); //ring terminal bell
 				messageQueue.Clear();
 				Console.Write(output);
-				Console.Write($"\u001b[{Math.Min(currentInputPos + prefixlen + 1, Console.LargestWindowWidth)}G");
+				Console.Write($"\u001b[{inputLine.relativeCursorPosition + prefixlen + 1}G");
 			}
 		}
 
@@ -450,7 +451,7 @@ namespace tgcli {
 			}
 
 			var rest = $"{text}{(msg.EditDate == 0 ? "" : $"{Ansi.Yellow}*")}";
-			
+
 			if (msg.InteractionInfo != null && msg.InteractionInfo.Reactions.Any(p => p.Type is ReactionType.ReactionTypeEmoji)) {
 				rest = $"{rest} {Ansi.Cyan}<--";
 				foreach (var reaction in msg.InteractionInfo.Reactions)
@@ -524,11 +525,11 @@ namespace tgcli {
 				 + $"{text}"
 				 + $"{Ansi.Yellow}*";
 		}
-		
+
 		private static string FormatMessage(Update.UpdateMessageUnreadReactions msg) {
 			string text;
 
-			var message   = GetMessage(msg.ChatId, msg.MessageId);
+			var message = GetMessage(msg.ChatId, msg.MessageId);
 			if (message.Content is MessageContent.MessageText messageText)
 				text = messageText.Text.Text;
 			else
@@ -590,12 +591,12 @@ namespace tgcli {
 					messageQueue.Add(formattedMessage);
 			ScreenUpdate();
 		}
-		
+
 		public static void AddMessageToQueue(Update.UpdateMessageUnreadReactions msg) {
 			//handle muted
 			if (IsMuted(GetChat(msg.ChatId)) && currentChatId != msg.ChatId)
 				return;
-			
+
 			if (!msg.UnreadReactions.Any(p => p.Type is ReactionType.ReactionTypeEmoji))
 				return;