import os
import subprocess
from unittest.mock import Mock

import pytest

from fenrirscreenreader.utils import x_clipboard


def command_exists(command):
    if command == "xclip":
        return "/usr/bin/xclip"
    return None


@pytest.mark.unit
def test_write_text_uses_display_env_without_mutating_process_env(
    monkeypatch,
):
    monkeypatch.delenv("DISPLAY", raising=False)
    monkeypatch.setattr(x_clipboard.shutil, "which", command_exists)
    run_command = Mock(
        return_value=subprocess.CompletedProcess(
            ["xclip"], 0, stdout=b"", stderr=b""
        )
    )
    monkeypatch.setattr(x_clipboard.subprocess, "run", run_command)

    assert x_clipboard.write_text("clipboard text", ":3") is True

    command = run_command.call_args.args[0]
    kwargs = run_command.call_args.kwargs
    assert command == ["xclip", "-selection", "clipboard"]
    assert kwargs["input"] == b"clipboard text"
    assert kwargs["env"]["DISPLAY"] == ":3"
    assert kwargs["timeout"] == 2.0
    assert os.environ.get("DISPLAY") is None


@pytest.mark.unit
def test_read_text_scans_displays_until_text_is_found(monkeypatch):
    monkeypatch.delenv("DISPLAY", raising=False)
    monkeypatch.setattr(x_clipboard.shutil, "which", command_exists)
    displays = []

    def run_command(command, **kwargs):
        displays.append(kwargs["env"].get("DISPLAY"))
        if kwargs["env"].get("DISPLAY") == ":1":
            return subprocess.CompletedProcess(
                command, 0, stdout=b"from x", stderr=b""
            )
        return subprocess.CompletedProcess(
            command, 1, stdout=b"", stderr=b"missing display"
        )

    monkeypatch.setattr(x_clipboard.subprocess, "run", run_command)

    assert x_clipboard.read_text(scan_displays=True) == "from x"
    assert displays == [":0", ":1"]


@pytest.mark.unit
def test_read_text_empty_success_returns_none(monkeypatch):
    monkeypatch.setenv("DISPLAY", ":2")
    monkeypatch.setattr(x_clipboard.shutil, "which", command_exists)
    monkeypatch.setattr(
        x_clipboard.subprocess,
        "run",
        Mock(
            return_value=subprocess.CompletedProcess(
                ["xclip"], 0, stdout=b"", stderr=b""
            )
        ),
    )

    assert x_clipboard.read_text() is None


@pytest.mark.unit
def test_write_text_propagates_clipboard_timeout(monkeypatch):
    monkeypatch.setattr(x_clipboard.shutil, "which", command_exists)
    timeout = subprocess.TimeoutExpired(["xclip"], 2.0)
    monkeypatch.setattr(
        x_clipboard.subprocess,
        "run",
        Mock(side_effect=timeout),
    )

    with pytest.raises(subprocess.TimeoutExpired):
        x_clipboard.write_text("clipboard text", ":3")