"""
Tests for engine.display module.
"""

from engine.display import NullDisplay, TerminalDisplay


class TestDisplayProtocol:
    """Test that display backends satisfy the Display protocol."""

    def test_terminal_display_is_display(self):
        """TerminalDisplay satisfies Display protocol."""
        display = TerminalDisplay()
        assert hasattr(display, "init")
        assert hasattr(display, "show")
        assert hasattr(display, "clear")
        assert hasattr(display, "cleanup")

    def test_null_display_is_display(self):
        """NullDisplay satisfies Display protocol."""
        display = NullDisplay()
        assert hasattr(display, "init")
        assert hasattr(display, "show")
        assert hasattr(display, "clear")
        assert hasattr(display, "cleanup")


class TestTerminalDisplay:
    """Tests for TerminalDisplay class."""

    def test_init_sets_dimensions(self):
        """init stores terminal dimensions."""
        display = TerminalDisplay()
        display.init(80, 24)
        assert display.width == 80
        assert display.height == 24

    def test_show_returns_none(self):
        """show returns None after writing to stdout."""
        display = TerminalDisplay()
        display.width = 80
        display.height = 24
        display.show(["line1", "line2"])

    def test_clear_does_not_error(self):
        """clear works without error."""
        display = TerminalDisplay()
        display.clear()

    def test_cleanup_does_not_error(self):
        """cleanup works without error."""
        display = TerminalDisplay()
        display.cleanup()


class TestNullDisplay:
    """Tests for NullDisplay class."""

    def test_init_stores_dimensions(self):
        """init stores dimensions."""
        display = NullDisplay()
        display.init(100, 50)
        assert display.width == 100
        assert display.height == 50

    def test_show_does_nothing(self):
        """show discards buffer without error."""
        display = NullDisplay()
        display.show(["line1", "line2", "line3"])

    def test_clear_does_nothing(self):
        """clear does nothing."""
        display = NullDisplay()
        display.clear()

    def test_cleanup_does_nothing(self):
        """cleanup does nothing."""
        display = NullDisplay()
        display.cleanup()