import fcntl
from pathlib import Path
import subprocess
import sys
import tempfile
import unittest
from unittest.mock import patch

from web_build_lock import cmake_build_tree, run_build


class BuildLockTests(unittest.TestCase):
    def test_build_tree_detection_resolves_relative_paths(self):
        self.assertEqual(cmake_build_tree(["/usr/bin/cmake", "--build", "cache", "--target", "Probe"], Path("/tmp")), Path("/tmp/cache"))
        self.assertIsNone(cmake_build_tree(["node", "test.mjs"], Path("/tmp")))

    def test_second_writer_cannot_enter_and_child_inherits_descriptor(self):
        with tempfile.TemporaryDirectory() as temporary:
            tree = Path(temporary)
            command = ["cmake", "--build", str(tree)]
            def child(_command, **kwargs):
                self.assertIn("pass_fds", kwargs)
                with (tree / ".freecad-web-build.lock").open("a") as second:
                    with self.assertRaises(BlockingIOError):
                        fcntl.flock(second.fileno(), fcntl.LOCK_EX | fcntl.LOCK_NB)
                code = "import os,sys; os.fstat(int(sys.argv[1]))"
                process = subprocess.Popen([sys.executable, "-c", code, str(kwargs["pass_fds"][-1])], pass_fds=kwargs["pass_fds"])
                self.assertEqual(process.wait(timeout=5), 0)
                return subprocess.CompletedProcess(command, 0)
            with patch("web_build_lock.subprocess.run", side_effect=child):
                self.assertEqual(run_build(command, cwd=tree).returncode, 0)
            with (tree / ".freecad-web-build.lock").open("a") as lock:
                fcntl.flock(lock.fileno(), fcntl.LOCK_EX | fcntl.LOCK_NB)

    def test_busy_tree_times_out_without_starting_a_build(self):
        with tempfile.TemporaryDirectory() as temporary:
            tree = Path(temporary)
            with (tree / ".freecad-web-build.lock").open("a") as lock:
                fcntl.flock(lock.fileno(), fcntl.LOCK_EX)
                with patch("web_build_lock.subprocess.run") as run:
                    with self.assertRaises(subprocess.TimeoutExpired):
                        run_build(["cmake", "--build", str(tree)], cwd=tree, timeout=0.03)
                    run.assert_not_called()

    def test_nonbuild_command_is_unchanged(self):
        with patch("web_build_lock.subprocess.run") as run:
            run_build(["node", "case.mjs"], cwd=Path("/tmp"), timeout=2)
            self.assertNotIn("pass_fds", run.call_args.kwargs)

    def test_missing_tree_is_not_created(self):
        with tempfile.TemporaryDirectory() as temporary:
            missing = Path(temporary) / "missing"
            with self.assertRaises(FileNotFoundError):
                run_build(["cmake", "--build", str(missing)], cwd=Path(temporary))
            self.assertFalse(missing.exists())


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