"""Unit tests for LibraryImportService — DB-free, in-memory fakes."""

import datetime as dt
import uuid
from collections.abc import Iterator
from pathlib import Path

import pytest
from app.application.import_service import LibraryImportService
from app.domain.entities import Artist, Track
from app.domain.sources import SourceFile, SourceInfo

pytestmark = pytest.mark.asyncio


class FakeArtistRepo:
    def __init__(self) -> None:
        self._by_name: dict[str, Artist] = {}

    async def get_or_create(self, name: str) -> Artist:
        if name not in self._by_name:
            now = dt.datetime.now(dt.UTC)
            self._by_name[name] = Artist(id=uuid.uuid4(), name=name, created_at=now, updated_at=now)
        return self._by_name[name]


class FakeTrackRepo:
    def __init__(self, *, fail_on: set[str] | None = None) -> None:
        self.by_source: dict[tuple[str, str], Track] = {}
        self.added: list[Track] = []
        self._fail_on = fail_on or set()

    async def get_by_source(self, source: str, source_id: str) -> Track | None:
        return self.by_source.get((source, source_id))

    async def add(self, **kw: object) -> Track:
        source_id = str(kw["source_id"])
        if source_id in self._fail_on:
            raise RuntimeError("simulated add failure")
        now = dt.datetime.now(dt.UTC)
        track = Track(
            id=uuid.UUID(str(kw["id"])) if not isinstance(kw["id"], uuid.UUID) else kw["id"],
            title=str(kw["title"]),
            artist_id=kw["artist_id"],  # type: ignore[arg-type]
            album_id=None,
            storage_uri=str(kw["storage_uri"]),
            file_format=str(kw["file_format"]),
            file_size=int(kw["file_size"]),  # type: ignore[call-overload]
            source=str(kw["source"]),
            source_id=source_id,
            duration_seconds=None,
            genre=None,
            year=None,
            track_number=None,
            metadata_status=str(kw["metadata_status"]),
            metadata_error=None,
            enriched_at=None,
            created_at=now,
            updated_at=now,
        )
        self.by_source[(track.source, track.source_id)] = track
        self.added.append(track)
        return track


class FakeStorage:
    def __init__(self) -> None:
        self.saved: dict[str, Path] = {}
        self.deleted: list[str] = []

    async def save_file(self, key: str, src_path: Path) -> int:
        self.saved[key] = src_path
        return 1

    async def delete(self, key: str) -> None:
        self.deleted.append(key)


class FakeSource:
    name = "local"

    def __init__(self, files: list[SourceFile]) -> None:
        self._files = files

    def info(self) -> SourceInfo:
        return SourceInfo(name=self.name, label="Local", kind="indexable", available=True)

    def is_available(self) -> bool:
        return True

    def scan(self) -> Iterator[SourceFile]:
        yield from self._files


def _file(source_id: str) -> SourceFile:
    return SourceFile(
        source_id=source_id,
        path=Path("/music") / source_id,
        suggested_title=Path(source_id).stem,
        file_format="mp3",
        file_size=123,
    )


def _service(tracks: FakeTrackRepo, storage: FakeStorage) -> LibraryImportService:
    return LibraryImportService(tracks=tracks, artists=FakeArtistRepo(), storage=storage)  # type: ignore[arg-type]


async def test_imports_new_files() -> None:
    tracks, storage = FakeTrackRepo(), FakeStorage()
    source = FakeSource([_file("a.mp3"), _file("b/c.mp3")])

    summary = await _service(tracks, storage).scan_and_import(source, added_by=None)  # type: ignore[arg-type]

    assert (summary.seen, summary.imported, summary.skipped, summary.failed) == (2, 2, 0, 0)
    assert len(tracks.added) == 2
    assert len(storage.saved) == 2
    assert all(t.metadata_status == "pending" for t in tracks.added)
    assert all(t.source == "local" for t in tracks.added)


async def test_dedup_skips_already_imported() -> None:
    tracks, storage = FakeTrackRepo(), FakeStorage()
    now = dt.datetime.now(dt.UTC)
    tracks.by_source[("local", "a.mp3")] = Track(
        id=uuid.uuid4(),
        title="a",
        artist_id=uuid.uuid4(),
        album_id=None,
        storage_uri="k",
        file_format="mp3",
        file_size=1,
        source="local",
        source_id="a.mp3",
        duration_seconds=None,
        genre=None,
        year=None,
        track_number=None,
        metadata_status="pending",
        metadata_error=None,
        enriched_at=None,
        created_at=now,
        updated_at=now,
    )
    source = FakeSource([_file("a.mp3"), _file("new.mp3")])

    summary = await _service(tracks, storage).scan_and_import(source, added_by=None)  # type: ignore[arg-type]

    assert (summary.imported, summary.skipped) == (1, 1)
    assert len(storage.saved) == 1  # only the new file copied


async def test_per_file_failure_is_isolated_and_rolls_back_storage() -> None:
    tracks = FakeTrackRepo(fail_on={"bad.mp3"})
    storage = FakeStorage()
    source = FakeSource([_file("good.mp3"), _file("bad.mp3")])

    summary = await _service(tracks, storage).scan_and_import(source, added_by=None)  # type: ignore[arg-type]

    assert (summary.seen, summary.imported, summary.failed) == (2, 1, 1)
    # The failed import's copied file was cleaned up; the good one stays.
    assert len(storage.deleted) == 1
    assert len(tracks.added) == 1