import importlib.util
import os
import tempfile
import unittest
from pathlib import Path
from unittest.mock import patch


def load_fortran_toolchain():
    module_path = Path(__file__).resolve().parent / "fortran_toolchain.py"
    spec = importlib.util.spec_from_file_location("fortran_toolchain", module_path)
    module = importlib.util.module_from_spec(spec)
    spec.loader.exec_module(module)
    return module


class FortranToolchainTests(unittest.TestCase):
    def test_auto_prefers_ifx_over_ifort_when_both_are_on_path(self):
        fortran_toolchain = load_fortran_toolchain()

        def fake_which(name):
            return f"C:\\oneapi\\{name}.exe" if name in {"ifx", "ifort"} else None

        with patch.object(fortran_toolchain.shutil, "which", side_effect=fake_which):
            with patch.dict(os.environ, {}, clear=True):
                toolchain = fortran_toolchain.resolve_toolchain()

        self.assertEqual(toolchain.name, "ifx")
        self.assertEqual(toolchain.executable, "C:\\oneapi\\ifx.exe")
        self.assertIsNone(toolchain.env_script)

    def test_auto_uses_oneapi_env_script_when_compiler_is_not_on_path(self):
        fortran_toolchain = load_fortran_toolchain()
        with tempfile.TemporaryDirectory() as tmp:
            vars_bat = Path(tmp) / "setvars.bat"
            vars_bat.write_text("@echo off\n", encoding="utf-8")

            with patch.object(fortran_toolchain.shutil, "which", return_value=None):
                with patch.object(fortran_toolchain, "ONEAPI_VARS_CANDIDATES", [vars_bat]):
                    with patch.dict(os.environ, {}, clear=True):
                        toolchain = fortran_toolchain.resolve_toolchain()

        self.assertEqual(toolchain.name, "ifx")
        self.assertEqual(toolchain.executable, "ifx")
        self.assertEqual(toolchain.env_script, vars_bat)

    def test_explicit_compiler_preference_is_honored(self):
        fortran_toolchain = load_fortran_toolchain()

        def fake_which(name):
            return f"C:\\oneapi\\{name}.exe"

        with patch.object(fortran_toolchain.shutil, "which", side_effect=fake_which):
            with patch.dict(os.environ, {"HARNESS_FORTRAN_COMPILER": "ifort"}, clear=True):
                toolchain = fortran_toolchain.resolve_toolchain()

        self.assertEqual(toolchain.name, "ifort")
        self.assertEqual(toolchain.executable, "C:\\oneapi\\ifort.exe")

    def test_wrap_command_calls_oneapi_env_before_compiler(self):
        fortran_toolchain = load_fortran_toolchain()
        toolchain = fortran_toolchain.FortranToolchain(
            name="ifx",
            executable="ifx",
            env_script=Path(r"C:\Program Files (x86)\Intel\oneAPI\setvars.bat"),
        )

        command = fortran_toolchain.wrap_command(toolchain, ["ifx", "/nologo", "test.f90"])

        self.assertIn("cmd /d /s /c", command)
        self.assertIn('call "C:\\Program Files (x86)\\Intel\\oneAPI\\setvars.bat" intel64', command)
        self.assertIn("ifx /nologo test.f90", command)


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