import hashlib
import json
import subprocess
import sys
import tempfile
import unittest
from pathlib import Path


ROOT = Path(__file__).resolve().parents[1]
MANIFEST = json.loads((ROOT / "manifest.json").read_text())["files"]
SCRIPT = ROOT / "scripts/apply.py"


class ApplyPatchTests(unittest.TestCase):
    def setUp(self):
        self.temp = tempfile.TemporaryDirectory()
        self.site = Path(self.temp.name)
        for name in MANIFEST:
            target = self.site / name
            target.parent.mkdir(parents=True, exist_ok=True)
            target.write_bytes((ROOT / "upstream" / name).read_bytes())

    def tearDown(self):
        self.temp.cleanup()

    def command(self, action):
        return subprocess.run(
            [sys.executable, str(SCRIPT), action, "--site-packages", str(self.site)],
            capture_output=True,
            text=True,
        )

    def test_apply_is_idempotent_and_rollback_restores_originals(self):
        self.assertEqual(self.command("--check").returncode, 0)
        for _ in range(2):
            result = self.command("--apply")
            self.assertEqual(result.returncode, 0, result.stderr)
        for name, hashes in MANIFEST.items():
            target = self.site / name
            self.assertEqual(hashlib.sha256(target.read_bytes()).hexdigest(), hashes["patched_sha256"])
            backup = target.with_name(target.name + ".ppu-dsv4.orig")
            self.assertEqual(hashlib.sha256(backup.read_bytes()).hexdigest(), hashes["original_sha256"])
        result = self.command("--rollback")
        self.assertEqual(result.returncode, 0, result.stderr)
        for name, hashes in MANIFEST.items():
            self.assertEqual(hashlib.sha256((self.site / name).read_bytes()).hexdigest(), hashes["original_sha256"])

    def test_unknown_base_refuses_before_any_file_is_changed(self):
        changed = self.site / next(iter(MANIFEST))
        changed.write_bytes(b"unexpected version\n")
        result = self.command("--apply")
        self.assertNotEqual(result.returncode, 0)
        self.assertIn("does not match", result.stderr)
        for name, hashes in list(MANIFEST.items())[1:]:
            self.assertEqual(hashlib.sha256((self.site / name).read_bytes()).hexdigest(), hashes["original_sha256"])


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