import os
from pathlib import Path
import shutil
import subprocess
import tempfile
import unittest

PRELOAD = Path(__file__).resolve().parents[1] / "linuxfs/preload"

PROGRAM = r"""
#include <stdio.h>
char *const *bl_webhelper_argv(const char *path, char *const argv[]);
int main(int argc, char **argv) {
  char *const *out = bl_webhelper_argv(argv[1], argv + 1);
  for (int i = 0; out[i]; i++) printf("%s\n", out[i]);
  return 0;
}
"""

WEBHELPER = "/root/.local/share/Steam/steamrtarm64/steamwebhelper"


@unittest.skipUnless(shutil.which("cc"), "needs cc")
class WebhelperPreloadTest(unittest.TestCase):
    @classmethod
    def setUpClass(cls):
        cls.tmp = Path(tempfile.mkdtemp())
        source = cls.tmp / "program.c"
        source.write_text(PROGRAM)
        cls.program = cls.tmp / "program"
        subprocess.run(["cc", "-O2", "-Wall", "-Werror", "-o", str(cls.program), str(source),
                        str(PRELOAD / "webhelper.c")], check=True)

    @classmethod
    def tearDownClass(cls):
        shutil.rmtree(cls.tmp, ignore_errors=True)

    def argv(self, *args, spec=None):
        env = {k: v for k, v in os.environ.items() if k != "BL_WEBHELPER_ARGS"}
        if spec is not None:
            env["BL_WEBHELPER_ARGS"] = spec
        result = subprocess.run([str(self.program), *args], env=env, capture_output=True, text=True, check=True)
        return result.stdout.splitlines()

    def test_the_browser_process_keeps_its_helpers_in_process(self):
        out = self.argv(WEBHELPER, "-lang=en_US", "--enable-features=A", "--no-sandbox", "--disable-features=B,C")
        self.assertEqual(out, [WEBHELPER, "-lang=en_US", "--no-sandbox", "--no-zygote", "--in-process-gpu",
                               "--enable-features=A", "--disable-features=B,C,AudioServiceOutOfProcess"])

    def test_feature_lists_are_added_when_steam_passes_none(self):
        out = self.argv(WEBHELPER, spec="+X -Y")
        self.assertEqual(out, [WEBHELPER, "--enable-features=X", "--disable-features=Y"])

    def test_child_processes_and_other_programs_are_left_alone(self):
        child = [WEBHELPER, "--type=renderer", "--enable-features=A"]
        self.assertEqual(self.argv(*child), child)
        other = ["/usr/bin/steam", "--enable-features=A"]
        self.assertEqual(self.argv(*other), other)

    def test_stock_turns_it_off(self):
        args = [WEBHELPER, "--enable-features=A"]
        self.assertEqual(self.argv(*args, spec="stock"), args)

    def test_angle_switches_are_appended_with_the_gpu_process_kept_out_of_process(self):
        out = self.argv(WEBHELPER, "-lang=en_US", "--enable-features=A", spec="--use-gl=angle --use-angle=vulkan")
        self.assertEqual(out, [WEBHELPER, "-lang=en_US", "--use-gl=angle", "--use-angle=vulkan",
                               "--enable-features=A"])
        self.assertNotIn("--in-process-gpu", out)

    def test_vulkan_compositing_features_join_steams_feature_list(self):
        out = self.argv(WEBHELPER, "--enable-features=PlatformHEVCDecoderSupport,V4L2VideoDecode",
                        spec="--use-gl=angle --use-angle=vulkan +Vulkan +VulkanFromANGLE +DefaultANGLEVulkan")
        self.assertEqual(out, [WEBHELPER, "--use-gl=angle", "--use-angle=vulkan",
                               "--enable-features=PlatformHEVCDecoderSupport,V4L2VideoDecode,"
                               "Vulkan,VulkanFromANGLE,DefaultANGLEVulkan"])

    def test_an_empty_setting_means_the_default(self):
        self.assertIn("--no-zygote", self.argv(WEBHELPER, spec=""))


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