// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

// Repro for: https://github.com/dotnet/runtime/pull/124254
// Main PR:   https://github.com/dotnet/runtime/pull/124254
// Servicing: https://github.com/dotnet/runtime/pull/124287 (10.0.4)
// Repro from: https://github.com/dotnet/runtime/pull/124287 (test cases)
//
// MakeLoopAtomic incorrectly wraps loops whose body contains backtracking
// constructs (e.g., lazy quantifiers, alternations). The atomic wrapper
// suppresses within-body backtracking, producing wrong match results.
// Expected: Regex matches the full intended substring.
// Actual:   Regex fails to match or matches incorrectly.

using System;
using System.Text.RegularExpressions;

class Repro_124254
{
    static int Main()
    {
        int failures = 0;

        // Lazy loop inside loop body: .*? must expand past first ) to find correct closing delimiter
        failures += Check(@"\w+(\(.*?\))?,", @"Foo(one()?,two,three),", @"Foo(one()?,two,three),");

        // Another variant: lazy dot-star inside optional group
        failures += Check(@"\w+(<.*?>)?!", "foo<a>b>!", "foo<a>b>!");

        // Greedy loop body with backtracking
        failures += Check(@"\w+(\(.+\))?,", "Foo(a),(b)x,", "Foo(a),");

        // Alternate inside loop body
        failures += Check(@"\w+(\((?:a|a\)b)\))?,", "Foo(a)b),", "Foo(a)b),");

        if (failures == 0)
        {
            Console.WriteLine("PASS: All regex patterns matched correctly");
            return 0;
        }

        Console.WriteLine($"FAIL: {failures} pattern(s) failed");
        return 1;
    }

    static int Check(string pattern, string input, string expected)
    {
        var match = Regex.Match(input, pattern);
        if (!match.Success || match.Value != expected)
        {
            Console.WriteLine($"FAIL: Pattern '{pattern}' on '{input}'");
            Console.WriteLine($"  Expected: '{expected}'");
            Console.WriteLine($"  Actual:   '{(match.Success ? match.Value : "(no match)")}'");
            return 1;
        }

        return 0;
    }
}