"""Tests for pager integration."""

from __future__ import annotations

import signal
import subprocess
from unittest.mock import MagicMock, patch

from rp.pager import MousePager, _mouse_capable_less


class TestMouseCapableLess:
    """Tests for _mouse_capable_less()."""

    def test_returns_path_when_less_supports_mouse(self) -> None:
        with patch("rp.pager.shutil.which", return_value="/usr/bin/less"):
            mock_result = MagicMock()
            mock_result.stdout = "less 551 (POSIX regular expressions)"
            mock_result.stderr = ""

            with patch("rp.pager.subprocess.run", return_value=mock_result):
                assert _mouse_capable_less() == "/usr/bin/less"

    def test_returns_none_when_less_not_found(self) -> None:
        with patch("rp.pager.shutil.which", return_value=None):
            assert _mouse_capable_less() is None

    def test_returns_none_when_less_too_old(self) -> None:
        with patch("rp.pager.shutil.which", return_value="/usr/bin/less"):
            mock_result = MagicMock()
            mock_result.stdout = "less 444"
            mock_result.stderr = ""

            with patch("rp.pager.subprocess.run", return_value=mock_result):
                assert _mouse_capable_less() is None

    def test_returns_path_when_version_is_in_stderr(self) -> None:
        with patch("rp.pager.shutil.which", return_value="/usr/bin/less"):
            mock_result = MagicMock()
            mock_result.stdout = ""
            mock_result.stderr = "less 600"

            with patch("rp.pager.subprocess.run", return_value=mock_result):
                assert _mouse_capable_less() == "/usr/bin/less"

    def test_returns_none_on_timeout(self) -> None:
        with patch("rp.pager.shutil.which", return_value="/usr/bin/less"):
            with patch(
                "rp.pager.subprocess.run",
                side_effect=subprocess.TimeoutExpired(cmd="less", timeout=5),
            ):
                assert _mouse_capable_less() is None

    def test_returns_none_on_os_error(self) -> None:
        with patch("rp.pager.shutil.which", return_value="/usr/bin/less"):
            with patch("rp.pager.subprocess.run", side_effect=OSError("nope")):
                assert _mouse_capable_less() is None

    def test_returns_none_when_version_not_parseable(self) -> None:
        with patch("rp.pager.shutil.which", return_value="/usr/bin/less"):
            mock_result = MagicMock()
            mock_result.stdout = "some random output"
            mock_result.stderr = ""

            with patch("rp.pager.subprocess.run", return_value=mock_result):
                assert _mouse_capable_less() is None

    def test_boundary_version_543(self) -> None:
        with patch("rp.pager.shutil.which", return_value="/usr/bin/less"):
            mock_result = MagicMock()
            mock_result.stdout = "less 543"
            mock_result.stderr = ""

            with patch("rp.pager.subprocess.run", return_value=mock_result):
                assert _mouse_capable_less() == "/usr/bin/less"

    def test_boundary_version_542(self) -> None:
        with patch("rp.pager.shutil.which", return_value="/usr/bin/less"):
            mock_result = MagicMock()
            mock_result.stdout = "less 542"
            mock_result.stderr = ""

            with patch("rp.pager.subprocess.run", return_value=mock_result):
                assert _mouse_capable_less() is None


class TestMousePager:
    """Tests for MousePager.show()."""

    def test_falls_back_to_system_pager_when_no_less(self) -> None:
        pager = MousePager()

        with patch("rp.pager._mouse_capable_less", return_value=None):
            with patch("rp.pager.SystemPager") as mock_system_pager:
                mock_instance = MagicMock()
                mock_system_pager.return_value = mock_instance

                pager.show("content")

                mock_instance.show.assert_called_once_with("content")

    def test_uses_less_when_available(self) -> None:
        pager = MousePager()
        mock_result = MagicMock()
        mock_result.returncode = 0

        with patch("rp.pager._mouse_capable_less", return_value="/usr/bin/less"):
            with patch("rp.pager.subprocess.run", return_value=mock_result) as mock_run:
                pager.show("hello")

                mock_run.assert_called_once_with(
                    ["/usr/bin/less", "-R", "--mouse"],
                    input="hello",
                    text=True,
                )

    def test_sigint_does_not_trigger_fallback_for_negative_code(self) -> None:
        pager = MousePager()
        mock_result = MagicMock()
        mock_result.returncode = -signal.SIGINT

        with patch("rp.pager._mouse_capable_less", return_value="/usr/bin/less"):
            with patch("rp.pager.subprocess.run", return_value=mock_result):
                with patch("rp.pager.SystemPager") as mock_system_pager:
                    pager.show("content")

                    mock_system_pager.assert_not_called()

    def test_sigint_does_not_trigger_fallback_for_128_plus_code(self) -> None:
        pager = MousePager()
        mock_result = MagicMock()
        mock_result.returncode = 128 + signal.SIGINT

        with patch("rp.pager._mouse_capable_less", return_value="/usr/bin/less"):
            with patch("rp.pager.subprocess.run", return_value=mock_result):
                with patch("rp.pager.SystemPager") as mock_system_pager:
                    pager.show("content")

                    mock_system_pager.assert_not_called()

    def test_nonzero_exit_triggers_fallback(self) -> None:
        pager = MousePager()
        mock_result = MagicMock()
        mock_result.returncode = 1

        with patch("rp.pager._mouse_capable_less", return_value="/usr/bin/less"):
            with patch("rp.pager.subprocess.run", return_value=mock_result):
                with patch("rp.pager.SystemPager") as mock_system_pager:
                    mock_instance = MagicMock()
                    mock_system_pager.return_value = mock_instance

                    pager.show("content")

                    mock_instance.show.assert_called_once_with("content")

    def test_oserror_triggers_fallback(self) -> None:
        pager = MousePager()

        with patch("rp.pager._mouse_capable_less", return_value="/usr/bin/less"):
            with patch("rp.pager.subprocess.run", side_effect=OSError("fail")):
                with patch("rp.pager.SystemPager") as mock_system_pager:
                    mock_instance = MagicMock()
                    mock_system_pager.return_value = mock_instance

                    pager.show("content")

                    mock_instance.show.assert_called_once_with("content")