import sys
import pytest
from unittest.mock import patch
from ctf.main import main

def test_main_entry_point_help():
    """
    Verifies that calling main() executes the Click CLI app and responds
    to '--help' by listing registration groups.
    """
    # Mock sys.argv to simulate running 'ctf --help' from the shell
    with patch.object(sys, "argv", ["ctf", "--help"]):
        # Click calls sys.exit() after displaying help, raising SystemExit
        with pytest.raises(SystemExit) as exc_info:
            main()
        
        # Verify it exits with a successful exit code (0)
        assert exc_info.value.code == 0

def test_flag_detector_stream_detection():
    """
    Verifies that FlagDetectorStream successfully intercepts writes to output potential flags.
    """
    from io import StringIO
    from ctf.main import FlagDetectorStream
    
    out = StringIO()
    stream = FlagDetectorStream(out, r"flag\{[a-z_]+\}")
    
    stream.write("Some text before flag{my_flag_here} and text after.")
    output = out.getvalue()
    assert "Potential flag(s) detected in command output" in output
    assert "flag{my_flag_here}" in output

def test_flag_detector_stream_anchored_stripping():
    """
    Verifies that FlagDetectorStream strips standard anchors ^ and $ to support substring searches.
    """
    from io import StringIO
    from ctf.main import FlagDetectorStream
    
    out = StringIO()
    stream = FlagDetectorStream(out, r"^flag\{[a-z_]+\}$")
    
    stream.write("random flag{my_flag_here} data")
    output = out.getvalue()
    assert "Potential flag(s) detected in command output" in output
    assert "flag{my_flag_here}" in output

def test_flag_detector_stream_no_pattern():
    """
    Verifies that FlagDetectorStream passes through text unmodified if no flag pattern is configured.
    """
    from io import StringIO
    from ctf.main import FlagDetectorStream
    
    out = StringIO()
    stream = FlagDetectorStream(out, "")
    
    stream.write("normal output flag{hello}")
    assert out.getvalue() == "normal output flag{hello}"