from __future__ import annotations

from pathlib import Path
import sys
import time
import unittest
from unittest.mock import patch


SRC_ROOT = Path(__file__).resolve().parents[2] / "src"

if str(SRC_ROOT) not in sys.path:
    sys.path.insert(0, str(SRC_ROOT))


from ffx.process import (  # noqa: E402
    COMMAND_NOT_FOUND_RETURN_CODE,
    COMMAND_TIMED_OUT_RETURN_CODE,
    executeProcess,
    getWrappedCommandSequence,
    normalizeCpuPercent,
    normalizeNiceness,
)


class ProcessTests(unittest.TestCase):
    def test_execute_process_returns_stdout_for_success(self):
        out, err, rc = executeProcess(
            [sys.executable, "-c", "print('hello from process')"]
        )

        self.assertEqual(0, rc)
        self.assertEqual("", err)
        self.assertEqual("hello from process\n", out)

    def test_execute_process_maps_missing_command_to_stable_error(self):
        out, err, rc = executeProcess(["ffx-command-that-does-not-exist"])

        self.assertEqual("", out)
        self.assertEqual(COMMAND_NOT_FOUND_RETURN_CODE, rc)
        self.assertIn("Command not found while running", err)
        self.assertIn("ffx-command-that-does-not-exist", err)

    def test_execute_process_maps_timeout_to_stable_error(self):
        out, err, rc = executeProcess(
            [sys.executable, "-c", "import time; time.sleep(0.2)"],
            timeoutSeconds=0.05,
        )

        self.assertEqual("", out)
        self.assertEqual(COMMAND_TIMED_OUT_RETURN_CODE, rc)
        self.assertIn("Command timed out", err)
        self.assertIn(sys.executable, err)

    def test_execute_process_can_stop_early_while_streaming_stderr(self):
        start = time.monotonic()
        observed_lines = []

        out, err, rc = executeProcess(
            [
                sys.executable,
                "-c",
                (
                    "import sys, time; "
                    "sys.stderr.write('fatal warning\\n'); sys.stderr.flush(); "
                    "time.sleep(2); "
                    "sys.stderr.write('late line\\n'); sys.stderr.flush()"
                ),
            ],
            stderrLineHandler=lambda line: observed_lines.append(line) or ("fatal warning" in line),
        )

        elapsed = time.monotonic() - start

        self.assertLess(elapsed, 1.5)
        self.assertNotEqual(0, rc)
        self.assertEqual("", out)
        self.assertIn("fatal warning", err)
        self.assertNotIn("late line", err)
        self.assertEqual(["fatal warning\n"], observed_lines)

    def test_get_wrapped_command_sequence_leaves_command_unwrapped_when_limits_disabled(self):
        wrapped = getWrappedCommandSequence(
            ["ffmpeg", "-i", "input.mkv"],
            context={"resource_limits": {"niceness": None, "cpu_percent": None}},
        )

        self.assertEqual(["ffmpeg", "-i", "input.mkv"], wrapped)

    def test_get_wrapped_command_sequence_wraps_nice_when_configured(self):
        wrapped = getWrappedCommandSequence(
            ["ffmpeg", "-i", "input.mkv"],
            context={"resource_limits": {"niceness": 5, "cpu_percent": None}},
        )

        self.assertEqual(["nice", "-n", "5", "ffmpeg", "-i", "input.mkv"], wrapped)

    def test_get_wrapped_command_sequence_wraps_cpulimit_around_nice_when_both_configured(self):
        wrapped = getWrappedCommandSequence(
            ["ffmpeg", "-i", "input.mkv"],
            context={"resource_limits": {"niceness": 5, "cpu_limit": 200}},
        )

        self.assertEqual(
            ["cpulimit", "-l", "200", "--", "nice", "-n", "5", "ffmpeg", "-i", "input.mkv"],
            wrapped,
        )

    def test_normalize_niceness_accepts_disabled_sentinel(self):
        self.assertIsNone(normalizeNiceness(99))

    def test_normalize_cpu_percent_accepts_disabled_sentinel(self):
        self.assertIsNone(normalizeCpuPercent(0))

    def test_normalize_cpu_percent_accepts_absolute_cpulimit_values(self):
        self.assertEqual(200, normalizeCpuPercent(200))

    def test_normalize_cpu_percent_converts_percent_of_present_cores(self):
        with patch("ffx.process.getPresentCpuCount", return_value=8):
            self.assertEqual(200, normalizeCpuPercent("25%"))


if __name__ == "__main__":
    unittest.main()