Mouse tracking conflict: Cannot use both text selection and cursor positioning simultaneously

[Abdelilah-AIT-HAMOU]

Problem
JLine3's mouse functionality has a fundamental conflict where enabling one mouse feature disables the other:

Option 1: JLine Mouse Mode
javaLineReader reader = LineReaderBuilder.builder()
.variable(LineReader.MOUSE, true)
.build();

✅ Text selection works (drag to select, copy/paste)
❌ Cursor positioning doesn't work (clicking to move cursor)

Option 2: Terminal Mouse Tracking
javaterminal.trackMouse(Terminal.MouseTracking.Button);
LineReader reader = LineReaderBuilder.builder()
.variable(LineReader.MOUSE, false)
.build();

✅ Cursor positioning works (click to move cursor)
❌ Text selection doesn't work (terminal intercepts all mouse events)

Impact
Developers must choose between two essential features that users expect in modern CLI applications. There's no way to have both:

Standard terminal text selection behavior
Convenient click-to-position cursor navigation

Root Cause
When Terminal.trackMouse() is enabled, it intercepts all mouse events at the terminal level, preventing JLine's LineReader from processing mouse events for text selection. The two systems compete for the same mouse input stream.
Expected Behavior
Both features should work simultaneously:

Users can drag to select text for copy/paste operations
Users can click to position the input cursor at specific locations

Is this the intended behavior, or should both features be able to work together? Text selection is a fundamental terminal operation that users expect to always be available.

Code to check this issue , uncomment which mode you want to test :

import java.io.IOException;
import org.jline.reader.LineReader;
import org.jline.reader.LineReaderBuilder;
import org.jline.terminal.Terminal;
import org.jline.terminal.TerminalBuilder;

/**
 * Simple JLine terminal to test mouse behavior:
 * - Cursor positioning (click to move cursor)
 * - Text selection (drag to select)
 * 
 * Compile and run:
 * javac -cp "reader/target/classes:terminal/target/classes" MouseTestTerminal.java
 * java -cp ".:reader/target/classes:terminal/target/classes" MouseTestTerminal
 */
public class MouseTestTerminal {
    
    public static void main(String[] args) throws IOException {
        System.out.println("=== JLine Mouse Test Terminal ===");
        System.out.println("Testing mouse cursor positioning and text selection");
        System.out.println("Commands: 'quit' to exit, anything else echoed back");
        System.out.println();
        
        Terminal terminal = TerminalBuilder.builder()
                .system(true)
                .build();
        
        // Test 1: JLine mouse only
        //testJLineMouseOnly(terminal);
        
        // Test 2: Terminal mouse only  
        //testTerminalMouseOnly(terminal);
        
        // Test 3: Smart switching
        testSmartMouseSwitching(terminal);
        
        terminal.close();
    }
    
    private static void testJLineMouseOnly(Terminal terminal) throws IOException {
        System.out.println("\n--- TEST 1: JLine Mouse Only ---");
        System.out.println("Expected: Text selection works, cursor positioning doesn't");
        
        LineReader reader = LineReaderBuilder.builder()
                .terminal(terminal)
                .variable(LineReader.MOUSE, true)
                .build();
        
        runTest(reader, terminal, "jline-only");
    }
    
    private static void testTerminalMouseOnly(Terminal terminal) throws IOException {
        System.out.println("\n--- TEST 2: Terminal Mouse Only ---");
        System.out.println("Expected: Cursor positioning works, text selection doesn't");
        
        terminal.trackMouse(Terminal.MouseTracking.Button);
        
        LineReader reader = LineReaderBuilder.builder()
                .terminal(terminal)
                .variable(LineReader.MOUSE, false)
                .build();
        
        runTest(reader, terminal, "terminal-only");
        
        terminal.trackMouse(Terminal.MouseTracking.Off);
    }
    
    private static void testSmartMouseSwitching(Terminal terminal) throws IOException {
        System.out.println("\n--- TEST 3: Smart Mouse Switching ---");
        System.out.println("Expected: Both cursor positioning AND text selection work");
        
        terminal.trackMouse(Terminal.MouseTracking.Button);
        
        LineReader reader = LineReaderBuilder.builder()
                .terminal(terminal)
                .variable(LineReader.MOUSE, false)
                .build();
        
        String input;
        int count = 0;
        while (true) {
            count++;
            
            // Disable mouse tracking during input for text selection
            terminal.trackMouse(Terminal.MouseTracking.Off);
            System.out.println("[DEBUG] Mouse OFF - text selection should work");
            
            input = reader.readLine("smart-test-" + count + "> ");
            
            // Re-enable mouse tracking after input for cursor positioning  
            terminal.trackMouse(Terminal.MouseTracking.Button);
            System.out.println("[DEBUG] Mouse ON - cursor positioning should work");
            
            if ("quit".equals(input.trim())) {
                break;
            }
            
            System.out.println("You entered: " + input);
            System.out.println("Try clicking to position cursor before next prompt...");
            try { Thread.sleep(2000); } catch (Exception e) {} // Give time to test cursor positioning
        }
        
        terminal.trackMouse(Terminal.MouseTracking.Off);
    }
    
    private static void runTest(LineReader reader, Terminal terminal, String testName) {
        String input;
        int count = 0;
        
        while (true) {
            count++;
            input = reader.readLine(testName + "-" + count + "> ");
            
            if ("quit".equals(input.trim())) {
                break;
            }
            
            System.out.println("You entered: " + input);
        }
    }
}