"""Unit tests for the unified storage layer (X14, services/storage.py).

Sync tests driving the async API via asyncio.run (matches the repo
convention — no pytest-asyncio). The filesystem backend is exercised against a
tmp DATA_DIR; the S3 path is stubbed so the suite needs no MinIO and no
aioboto3.
"""
import asyncio

import pytest

from legal_mcp import config
from legal_mcp.services import storage
from legal_mcp.services.storage import Bucket


@pytest.fixture(autouse=True)
def _tmp_datadir(tmp_path, monkeypatch):
    monkeypatch.setattr(config, "DATA_DIR", tmp_path)
    monkeypatch.setattr(config, "STORAGE_BACKEND", "filesystem")
    storage.reset_storage_cache()
    yield tmp_path
    storage.reset_storage_cache()


def run(coro):
    return asyncio.run(coro)


# ── normalize_key ──────────────────────────────────────────────────

def test_normalize_key_relative():
    assert storage.normalize_key("cases/8174-24/originals/x.pdf") == \
        "cases/8174-24/originals/x.pdf"


def test_normalize_key_rejects_parent_traversal():
    with pytest.raises(ValueError):
        storage.normalize_key("cases/../../etc/passwd")


def test_normalize_key_accepts_abs_under_datadir(_tmp_datadir):
    abs_key = _tmp_datadir / "cases" / "x.pdf"
    assert storage.normalize_key(abs_key) == "cases/x.pdf"


def test_normalize_key_rejects_abs_outside_datadir():
    with pytest.raises(ValueError):
        storage.normalize_key("/var/secret/x.pdf")


# ── filesystem backend ─────────────────────────────────────────────

def test_filesystem_roundtrip(_tmp_datadir):
    be = storage.FilesystemBackend()
    key = "cases/1/originals/a.pdf"
    uri = run(be.put_bytes(key, b"hello", content_type="application/pdf"))
    assert uri.startswith("file://")
    assert (_tmp_datadir / key).read_bytes() == b"hello"
    assert run(be.exists(key)) is True
    assert run(be.get_bytes(key)) == b"hello"
    run(be.delete(key))
    assert run(be.exists(key)) is False
    # delete is idempotent (missing_ok)
    run(be.delete(key))


def test_filesystem_put_file(_tmp_datadir):
    be = storage.FilesystemBackend()
    src = _tmp_datadir / "src.bin"
    src.write_bytes(b"payload")
    run(be.put_file(src, "precedent-library/court_ruling/u.pdf"))
    assert (_tmp_datadir / "precedent-library/court_ruling/u.pdf").read_bytes() == b"payload"


def test_filesystem_bucket_is_ignored_legacy_layout(_tmp_datadir):
    """Even for a non-default bucket, the FS backend keeps the single tree —
    so the default backend is byte-for-byte the legacy layout."""
    be = storage.FilesystemBackend()
    run(be.put_bytes("thumbnails/d/p001.jpg", b"img", bucket=Bucket.DERIVED))
    assert (_tmp_datadir / "thumbnails/d/p001.jpg").exists()


def test_filesystem_list_keys(_tmp_datadir):
    be = storage.FilesystemBackend()
    run(be.put_bytes("cases/1/a.txt", b"a"))
    run(be.put_bytes("cases/1/sub/b.txt", b"b"))
    run(be.put_bytes("cases/2/c.txt", b"c"))
    keys = run(be.list_keys("cases/1"))
    assert keys == ["cases/1/a.txt", "cases/1/sub/b.txt"]


def test_filesystem_local_path_and_ensure_local(_tmp_datadir):
    be = storage.FilesystemBackend()
    run(be.put_bytes("cases/1/a.pdf", b"x"))
    assert be.local_path("cases/1/a.pdf") == (_tmp_datadir / "cases/1/a.pdf").resolve()
    assert be.local_path("cases/1/missing.pdf") is None
    # ensure_local returns the real path without copying
    assert run(be.ensure_local("cases/1/a.pdf")) == (_tmp_datadir / "cases/1/a.pdf").resolve()


def test_filesystem_presign_unsupported(_tmp_datadir):
    be = storage.FilesystemBackend()
    with pytest.raises(NotImplementedError):
        run(be.presign_get("cases/1/a.pdf"))


# ── backend selection ──────────────────────────────────────────────

def test_get_storage_default_is_filesystem(monkeypatch):
    monkeypatch.setattr(config, "STORAGE_BACKEND", "filesystem")
    storage.reset_storage_cache()
    assert isinstance(storage.get_storage(), storage.FilesystemBackend)


def test_get_storage_unknown_falls_back(monkeypatch):
    monkeypatch.setattr(config, "STORAGE_BACKEND", "bogus")
    storage.reset_storage_cache()
    assert isinstance(storage.get_storage(), storage.FilesystemBackend)


def test_get_storage_dual(monkeypatch):
    monkeypatch.setattr(config, "STORAGE_BACKEND", "dual")
    storage.reset_storage_cache()
    assert isinstance(storage.get_storage(), storage.DualBackend)


# ── dual backend (S3 stubbed) ──────────────────────────────────────

class _FakeS3:
    """Minimal async S3 stub. ``store`` None ⇒ S3 'down' (raises)."""

    def __init__(self, store):
        self.store = store  # dict or None

    async def put_bytes(self, key, data, *, bucket=Bucket.DOCUMENTS, content_type=None, metadata=None):
        if self.store is None:
            raise RuntimeError("s3 down")
        self.store[storage.normalize_key(key)] = data
        return f"s3://stub/{storage.normalize_key(key)}"

    async def put_file(self, src, key, *, bucket=Bucket.DOCUMENTS, content_type=None, metadata=None):
        with open(src, "rb") as fh:
            return await self.put_bytes(key, fh.read(), bucket=bucket)

    async def get_bytes(self, key, *, bucket=Bucket.DOCUMENTS):
        if self.store is None:
            raise RuntimeError("s3 down")
        return self.store[storage.normalize_key(key)]

    async def exists(self, key, *, bucket=Bucket.DOCUMENTS):
        return self.store is not None and storage.normalize_key(key) in self.store

    async def delete(self, key, *, bucket=Bucket.DOCUMENTS):
        if self.store is not None:
            self.store.pop(storage.normalize_key(key), None)


def _dual_with(store):
    dual = storage.DualBackend()
    dual.s3 = _FakeS3(store)
    return dual


def test_dual_writes_both(_tmp_datadir):
    store = {}
    dual = _dual_with(store)
    run(dual.put_bytes("cases/1/a.pdf", b"data"))
    assert (_tmp_datadir / "cases/1/a.pdf").read_bytes() == b"data"   # disk
    assert store["cases/1/a.pdf"] == b"data"                          # s3


def test_dual_s3_write_failure_does_not_break(_tmp_datadir):
    dual = _dual_with(None)  # s3 down
    # disk write still succeeds; s3 failure is logged, not raised
    run(dual.put_bytes("cases/1/a.pdf", b"data"))
    assert (_tmp_datadir / "cases/1/a.pdf").read_bytes() == b"data"


def test_dual_get_prefers_s3(_tmp_datadir):
    dual = _dual_with({"cases/1/a.pdf": b"from-s3"})
    run(dual.fs.put_bytes("cases/1/a.pdf", b"from-disk"))
    assert run(dual.get_bytes("cases/1/a.pdf")) == b"from-s3"


def test_dual_get_falls_back_to_disk(_tmp_datadir):
    dual = _dual_with(None)  # s3 down → must read disk
    run(dual.fs.put_bytes("cases/1/a.pdf", b"from-disk"))
    assert run(dual.get_bytes("cases/1/a.pdf")) == b"from-disk"


def test_bucket_name_resolution(monkeypatch):
    monkeypatch.setattr(config, "MINIO_BUCKET_DOCUMENTS", "legal-documents")
    monkeypatch.setattr(config, "MINIO_BUCKET_IMMUTABLE", "legal-immutable")
    monkeypatch.setattr(config, "MINIO_BUCKET_DERIVED", "legal-derived")
    assert storage._bucket_name(Bucket.DOCUMENTS) == "legal-documents"
    assert storage._bucket_name(Bucket.IMMUTABLE) == "legal-immutable"
    assert storage._bucket_name(Bucket.DERIVED) == "legal-derived"