#!/usr/bin/env python3
from __future__ import annotations

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

from data_get_sync import (
    DataGetSync,
    parse_manifest,
    safe_episode_name,
    safe_relative_path,
    validate_episode_dir,
)


class DataGetSyncTests(unittest.TestCase):
    def test_safe_episode_name(self) -> None:
        self.assertTrue(safe_episode_name("episode_20260810T120000000_deadbeef"))
        self.assertFalse(safe_episode_name("../escape"))
        self.assertFalse(safe_episode_name("bad/name"))
        self.assertFalse(safe_episode_name(""))

    def test_safe_relative_path(self) -> None:
        self.assertEqual(safe_relative_path("bag/metadata.yaml"), Path("bag/metadata.yaml"))
        for invalid in ("", "/etc/passwd", "../escape", "bag/../../escape", None):
            with self.subTest(invalid=invalid):
                with self.assertRaises(ValueError):
                    safe_relative_path(invalid)

    def _episode(self, root: Path, name: str) -> tuple[Path, dict]:
        episode = root / name
        (episode / "bag").mkdir(parents=True)
        mcap = episode / "bag" / "bag_0.mcap"
        metadata = episode / "bag" / "metadata.yaml"
        mcap.write_bytes(b"mcap-data")
        metadata.write_text("rosbag2_bagfile_information: {}\n", encoding="utf-8")
        files = []
        for path in (mcap, metadata):
            raw = path.read_bytes()
            files.append(
                {
                    "path": str(path.relative_to(episode)),
                    "size": len(raw),
                    "sha256": hashlib.sha256(raw).hexdigest(),
                }
            )
        manifest = {"state": "complete", "episode_id": name, "files": files}
        (episode / "manifest.json").write_text(json.dumps(manifest), encoding="utf-8")
        (episode / "READY").write_text("ready\n", encoding="ascii")
        return episode, manifest

    def test_parse_and_validate_episode(self) -> None:
        with tempfile.TemporaryDirectory() as temporary:
            name = "episode_20260810T120000000_deadbeef"
            episode, manifest = self._episode(Path(temporary), name)
            parsed = parse_manifest(json.dumps(manifest), name)
            validate_episode_dir(episode, parsed)

    def test_manifest_requires_complete_matching_episode_and_mcap(self) -> None:
        digest = "0" * 64
        base = {
            "state": "complete",
            "episode_id": "episode_ok",
            "files": [{"path": "bag/bag_0.mcap", "size": 1, "sha256": digest}],
        }
        with self.assertRaises(ValueError):
            parse_manifest(json.dumps({**base, "state": "active"}), "episode_ok")
        with self.assertRaises(ValueError):
            parse_manifest(json.dumps(base), "episode_other")
        no_mcap = {
            **base,
            "files": [{"path": "bag/metadata.yaml", "size": 1, "sha256": digest}],
        }
        with self.assertRaises(ValueError):
            parse_manifest(json.dumps(no_mcap), "episode_ok")

    def test_validate_detects_tampering(self) -> None:
        with tempfile.TemporaryDirectory() as temporary:
            name = "episode_20260810T120000000_deadbeef"
            episode, manifest = self._episode(Path(temporary), name)
            (episode / "bag" / "bag_0.mcap").write_bytes(b"changed")
            with self.assertRaises(ValueError):
                validate_episode_dir(episode, manifest)

    def test_validate_requires_regular_ready_marker(self) -> None:
        with tempfile.TemporaryDirectory() as temporary:
            name = "episode_20260810T120000000_deadbeef"
            episode, manifest = self._episode(Path(temporary), name)
            (episode / "READY").unlink()
            with self.assertRaises(ValueError):
                validate_episode_dir(episode, manifest)

    def test_existing_episode_skips_expensive_hash_unless_requested(self) -> None:
        with tempfile.TemporaryDirectory() as temporary:
            root = Path(temporary)
            name = "episode_20260810T120000000_deadbeef"
            episode, _manifest = self._episode(root, name)
            (episode / "bag" / "bag_0.mcap").write_bytes(b"changed")
            fast = DataGetSync(
                remote="unused",
                remote_ready="/unused",
                destination=root,
                status_file=root / "status.json",
            )
            self.assertFalse(fast.sync_episode(name))
            deep = DataGetSync(
                remote="unused",
                remote_ready="/unused",
                destination=root,
                status_file=root / "status.json",
                verify_existing=True,
            )
            with self.assertRaises(ValueError):
                deep.sync_episode(name)

    def test_bad_old_episode_does_not_starve_newer_episode(self) -> None:
        with tempfile.TemporaryDirectory() as temporary:
            root = Path(temporary)

            class ProbeSync(DataGetSync):
                def __init__(self) -> None:
                    super().__init__(
                        remote="unused",
                        remote_ready="/unused",
                        destination=root,
                        status_file=root / "status.json",
                    )
                    self.seen: list[str] = []

                def list_remote_episodes(self) -> list[str]:
                    return ["episode_bad", "episode_new"]

                def sync_episode(self, episode: str) -> bool:
                    self.seen.append(episode)
                    if episode == "episode_bad":
                        raise RuntimeError("damaged")
                    return True

            syncer = ProbeSync()
            with self.assertRaises(RuntimeError):
                syncer.run_once()
            self.assertEqual(syncer.seen, ["episode_bad", "episode_new"])


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