"""Tests for app.storage.object_store — local-filesystem object store.

Exercises the async hash-dedup store against a real tmp_path on disk. All disk
I/O is dispatched via ``asyncio.to_thread`` so the methods are genuinely async.
"""

from __future__ import annotations

import hashlib
from pathlib import Path

from app.storage.object_store import ObjectStore

# ---------------------------------------------------------------------------
# put_bytes / get_path / exists
# ---------------------------------------------------------------------------


async def test_put_bytes_writes_file_and_exists_reports_true(tmp_path: Path):
    """put_bytes writes the blob; exists() then reports True; path matches key."""
    store = ObjectStore(tmp_path)
    key = "foo/bar.txt"
    data = b"hello"

    assert await store.exists(key) is False

    path = await store.put_bytes(key, data)
    assert path == tmp_path / key
    assert path.exists()
    assert path.read_bytes() == data

    assert await store.exists(key) is True


async def test_get_path_returns_base_plus_key(tmp_path: Path):
    """get_path is a pure path computation (no I/O).

    ``/`` in the key becomes real path segments (subdirectories).
    """
    store = ObjectStore(tmp_path)
    assert store.get_path("a/b/c.bin") == tmp_path / "a" / "b" / "c.bin"
    assert store.get_path("flat.txt") == tmp_path / "flat.txt"


async def test_put_bytes_overwrites_on_change(tmp_path: Path):
    """A second put_bytes with new content overwrites the file."""
    store = ObjectStore(tmp_path)
    await store.put_bytes("k", b"v1")
    await store.put_bytes("k", b"v2")
    assert (tmp_path / "k").read_bytes() == b"v2"


# ---------------------------------------------------------------------------
# put_by_hash (dedup)
# ---------------------------------------------------------------------------


async def test_put_by_hash_returns_sha256_and_path_with_layout(tmp_path: Path):
    """Returns (sha256_hex, base/<2 chars>/<hash><ext>); file content correct."""
    store = ObjectStore(tmp_path)
    data = b"abc"
    expected_hash = hashlib.sha256(data).hexdigest()

    h, path = await store.put_by_hash(data, ext=".txt")

    assert h == expected_hash
    assert path == tmp_path / expected_hash[:2] / (expected_hash + ".txt")
    assert path.exists()
    assert path.read_bytes() == data


async def test_put_by_hash_dedups_same_bytes_returns_same_path(tmp_path: Path):
    """put_by_hash with identical bytes twice -> same (hash, path)."""
    store = ObjectStore(tmp_path)
    data = b"identical"

    h1, p1 = await store.put_by_hash(data)
    h2, p2 = await store.put_by_hash(data)

    assert h1 == h2
    assert p1 == p2


async def test_put_by_hash_does_not_rewrite_existing_file(tmp_path: Path):
    """Dedup: a second call for an existing hash must NOT touch the file.

    Proves the implementation checks ``exists`` before writing. We corrupt the
    file between calls; a dedup-aware store must leave the corruption in place
    (no rewrite), since the blob is already present.
    """
    store = ObjectStore(tmp_path)
    data = b"original"

    _h1, p1 = await store.put_by_hash(data, ext=".bin")
    assert p1.read_bytes() == data

    # Corrupt the on-disk file.
    p1.write_bytes(b"CORRUPTED")

    _h2, p2 = await store.put_by_hash(data, ext=".bin")
    assert p2 == p1
    # Dedup short-circuit: file content was NOT overwritten.
    assert p2.read_bytes() == b"CORRUPTED"


async def test_put_by_hash_distinct_bytes_get_distinct_paths(tmp_path: Path):
    """Different bytes -> different hash -> different path."""
    store = ObjectStore(tmp_path)
    h1, p1 = await store.put_by_hash(b"aaa")
    h2, p2 = await store.put_by_hash(b"bbb")
    assert h1 != h2
    assert p1 != p2


async def test_put_by_hash_default_ext_empty(tmp_path: Path):
    """Default ext='' -> no suffix appended to the file."""
    store = ObjectStore(tmp_path)
    data = b"x"
    expected_hash = hashlib.sha256(data).hexdigest()
    h, p = await store.put_by_hash(data)
    assert h == expected_hash
    assert p == tmp_path / expected_hash[:2] / expected_hash


# ---------------------------------------------------------------------------
# put_stream
# ---------------------------------------------------------------------------


async def test_put_stream_writes_concatenated_chunks(tmp_path: Path):
    """put_stream consumes an async generator and writes concatenated bytes."""

    async def gen():
        yield b"chunk1-"
        yield b"chunk2-"
        yield b"chunk3"

    store = ObjectStore(tmp_path)
    path = await store.put_stream("streamed/key", gen())
    assert path == tmp_path / "streamed" / "key"
    assert path.read_bytes() == b"chunk1-chunk2-chunk3"


# ---------------------------------------------------------------------------
# Default base dir (Settings.media_dir)
# ---------------------------------------------------------------------------


def test_object_store_default_base_uses_settings_media_dir(tmp_path: Path, monkeypatch):
    """Omitting base_dir falls back to Settings.media_dir."""
    monkeypatch.setenv("MEDIA_DIR", str(tmp_path))
    from app.config import get_settings

    get_settings.cache_clear()
    store = ObjectStore()
    assert store.base_dir == get_settings().media_dir