import os
from pathlib import Path
from types import SimpleNamespace
from unittest.mock import AsyncMock

import pytest

from py.services.download_manager import DownloadManager
from py.services import download_manager
from py.services.service_registry import ServiceRegistry
from py.services.settings_manager import settings
from py.utils.metadata_manager import MetadataManager


@pytest.fixture(autouse=True)
def reset_download_manager():
    """Ensure each test operates on a fresh singleton."""
    DownloadManager._instance = None
    yield
    DownloadManager._instance = None


@pytest.fixture(autouse=True)
def isolate_settings(monkeypatch, tmp_path):
    """Point settings writes at a temporary directory to avoid touching real files."""
    default_settings = settings._get_default_settings()
    default_settings.update(
        {
            "default_lora_root": str(tmp_path),
            "default_checkpoint_root": str(tmp_path / "checkpoints"),
            "default_embedding_root": str(tmp_path / "embeddings"),
            "download_path_templates": {
                "lora": "{base_model}/{first_tag}",
                "checkpoint": "{base_model}/{first_tag}",
                "embedding": "{base_model}/{first_tag}",
            },
            "base_model_path_mappings": {"BaseModel": "MappedModel"},
        }
    )
    monkeypatch.setattr(settings, "settings", default_settings)
    monkeypatch.setattr(type(settings), "_save_settings", lambda self: None)


@pytest.fixture(autouse=True)
def stub_metadata(monkeypatch):
    class _StubMetadata:
        def __init__(self, save_path: str):
            self.file_path = save_path
            self.sha256 = "sha256"
            self.file_name = Path(save_path).stem

    def _factory(save_path: str):
        return _StubMetadata(save_path)

    def _make_class():
        @staticmethod
        def from_civitai_info(_version_info, _file_info, save_path):
            return _factory(save_path)

        return type("StubMetadata", (), {"from_civitai_info": from_civitai_info})

    stub_class = _make_class()
    monkeypatch.setattr(download_manager, "LoraMetadata", stub_class)
    monkeypatch.setattr(download_manager, "CheckpointMetadata", stub_class)
    monkeypatch.setattr(download_manager, "EmbeddingMetadata", stub_class)


class DummyScanner:
    def __init__(self, exists: bool = False):
        self.exists = exists
        self.calls = []

    async def check_model_version_exists(self, version_id):
        self.calls.append(version_id)
        return self.exists


@pytest.fixture
def scanners(monkeypatch):
    lora_scanner = DummyScanner()
    checkpoint_scanner = DummyScanner()
    embedding_scanner = DummyScanner()

    monkeypatch.setattr(ServiceRegistry, "get_lora_scanner", AsyncMock(return_value=lora_scanner))
    monkeypatch.setattr(ServiceRegistry, "get_checkpoint_scanner", AsyncMock(return_value=checkpoint_scanner))
    monkeypatch.setattr(ServiceRegistry, "get_embedding_scanner", AsyncMock(return_value=embedding_scanner))

    return SimpleNamespace(
        lora=lora_scanner,
        checkpoint=checkpoint_scanner,
        embedding=embedding_scanner,
    )


@pytest.fixture
def metadata_provider(monkeypatch):
    class DummyProvider:
        def __init__(self):
            self.calls = []

        async def get_model_version(self, model_id, model_version_id):
            self.calls.append((model_id, model_version_id))
            return {
                "id": 42,
                "model": {"type": "LoRA", "tags": ["fantasy"]},
                "baseModel": "BaseModel",
                "creator": {"username": "Author"},
                "files": [
                    {
                        "primary": True,
                        "downloadUrl": "https://example.invalid/file.safetensors",
                        "name": "file.safetensors",
                    }
                ],
            }

    provider = DummyProvider()
    monkeypatch.setattr(
        download_manager,
        "get_default_metadata_provider",
        AsyncMock(return_value=provider),
    )
    return provider


@pytest.fixture(autouse=True)
def noop_cleanup(monkeypatch):
    async def _cleanup(self, task_id):
        if task_id in self._active_downloads:
            self._active_downloads[task_id]["cleaned"] = True

    monkeypatch.setattr(DownloadManager, "_cleanup_download_record", _cleanup)


async def test_download_requires_identifier():
    manager = DownloadManager()
    result = await manager.download_from_civitai()
    assert result == {
        "success": False,
        "error": "Either model_id or model_version_id must be provided",
    }


async def test_successful_download_uses_defaults(monkeypatch, scanners, metadata_provider, tmp_path):
    manager = DownloadManager()

    captured = {}

    async def fake_execute_download(
        self,
        *,
        download_urls,
        save_dir,
        metadata,
        version_info,
        relative_path,
        progress_callback,
        model_type,
        download_id,
    ):
        captured.update(
            {
                "download_urls": download_urls,
                "save_dir": Path(save_dir),
                "relative_path": relative_path,
                "progress_callback": progress_callback,
                "model_type": model_type,
                "download_id": download_id,
                "metadata_path": metadata.file_path,
            }
        )
        return {"success": True}

    monkeypatch.setattr(DownloadManager, "_execute_download", fake_execute_download, raising=False)

    result = await manager.download_from_civitai(
        model_version_id=99,
        save_dir=str(tmp_path),
        use_default_paths=True,
        progress_callback=None,
        source=None,
    )

    assert result["success"] is True
    assert "download_id" in result
    assert manager._download_tasks == {}
    assert manager._active_downloads[result["download_id"]]["status"] == "completed"

    assert captured["relative_path"] == "MappedModel/fantasy"
    expected_dir = Path(settings.get("default_lora_root")) / "MappedModel" / "fantasy"
    assert captured["save_dir"] == expected_dir
    assert captured["model_type"] == "lora"
    assert captured["download_urls"] == [
        "https://example.invalid/file.safetensors"
    ]


async def test_download_uses_active_mirrors(monkeypatch, scanners, metadata_provider, tmp_path):
    manager = DownloadManager()

    metadata_with_mirrors = {
        "id": 42,
        "model": {"type": "LoRA", "tags": ["fantasy"]},
        "baseModel": "BaseModel",
        "creator": {"username": "Author"},
        "files": [
            {
                "primary": True,
                "downloadUrl": "https://example.invalid/file.safetensors",
                "mirrors": [
                    {"url": "https://mirror.example/file.safetensors", "deletedAt": None},
                    {"url": "https://mirror.example/old.safetensors", "deletedAt": "2024-01-01"},
                ],
                "name": "file.safetensors",
            }
        ],
    }

    metadata_provider.get_model_version = AsyncMock(return_value=metadata_with_mirrors)

    captured = {}

    async def fake_execute_download(
        self,
        *,
        download_urls,
        save_dir,
        metadata,
        version_info,
        relative_path,
        progress_callback,
        model_type,
        download_id,
    ):
        captured["download_urls"] = download_urls
        return {"success": True}

    monkeypatch.setattr(DownloadManager, "_execute_download", fake_execute_download, raising=False)

    result = await manager.download_from_civitai(
        model_version_id=99,
        save_dir=str(tmp_path),
        use_default_paths=True,
        progress_callback=None,
        source=None,
    )

    assert result["success"] is True
    assert captured["download_urls"] == ["https://mirror.example/file.safetensors"]


async def test_download_aborts_when_version_exists(monkeypatch, scanners, metadata_provider):
    scanners.lora.exists = True

    manager = DownloadManager()

    execute_mock = AsyncMock(return_value={"success": True})
    monkeypatch.setattr(DownloadManager, "_execute_download", execute_mock)

    result = await manager.download_from_civitai(model_version_id=101, save_dir="/tmp")

    assert result["success"] is False
    assert result["error"] == "Model version already exists in lora library"
    assert "download_id" in result
    assert execute_mock.await_count == 0


async def test_download_handles_metadata_errors(monkeypatch, scanners):
    async def failing_provider(*_args, **_kwargs):
        return None

    monkeypatch.setattr(
        download_manager,
        "get_default_metadata_provider",
        AsyncMock(return_value=SimpleNamespace(get_model_version=AsyncMock(return_value=None))),
    )

    manager = DownloadManager()

    result = await manager.download_from_civitai(model_version_id=5, save_dir="/tmp")

    assert result["success"] is False
    assert result["error"] == "Failed to fetch model metadata"
    assert "download_id" in result


async def test_download_rejects_unsupported_model_type(monkeypatch, scanners):
    class Provider:
        async def get_model_version(self, *_args, **_kwargs):
            return {
                "model": {"type": "Unsupported", "tags": []},
                "files": [],
            }

    monkeypatch.setattr(
        download_manager,
        "get_default_metadata_provider",
        AsyncMock(return_value=Provider()),
    )

    manager = DownloadManager()

    result = await manager.download_from_civitai(model_version_id=5, save_dir="/tmp")

    assert result["success"] is False
    assert result["error"].startswith("Model type")


def test_embedding_relative_path_replaces_spaces():
    manager = DownloadManager()

    version_info = {
        "baseModel": "Base Model",
        "model": {"tags": ["tag with space"]},
        "creator": {"username": "Author Name"},
    }

    relative_path = manager._calculate_relative_path(version_info, "embedding")

    assert relative_path == "Base_Model/tag_with_space"


async def test_execute_download_retries_urls(monkeypatch, tmp_path):
    manager = DownloadManager()

    save_dir = tmp_path / "downloads"
    save_dir.mkdir()
    initial_path = save_dir / "file.safetensors"

    class DummyMetadata:
        def __init__(self, path: Path):
            self.file_path = str(path)
            self.sha256 = "sha256"
            self.file_name = path.stem
            self.preview_url = None

        def generate_unique_filename(self, *_args, **_kwargs):
            return os.path.basename(self.file_path)

        def update_file_info(self, _path):
            return None

        def to_dict(self):
            return {"file_path": self.file_path}

    metadata = DummyMetadata(initial_path)
    version_info = {"images": []}
    download_urls = [
        "https://first.example/file.safetensors",
        "https://second.example/file.safetensors",
    ]

    class DummyDownloader:
        def __init__(self):
            self.calls = []

        async def download_file(self, url, path, progress_callback=None, use_auth=None):
            self.calls.append((url, path, use_auth))
            if len(self.calls) == 1:
                return False, "first failed"
            # Create the target file to simulate a successful download
            Path(path).write_text("content")
            return True, "second success"

    dummy_downloader = DummyDownloader()
    monkeypatch.setattr(download_manager, "get_downloader", AsyncMock(return_value=dummy_downloader))

    class DummyScanner:
        def __init__(self):
            self.calls = []

        async def add_model_to_cache(self, metadata_dict, relative_path):
            self.calls.append((metadata_dict, relative_path))

    dummy_scanner = DummyScanner()
    monkeypatch.setattr(DownloadManager, "_get_lora_scanner", AsyncMock(return_value=dummy_scanner))
    monkeypatch.setattr(DownloadManager, "_get_checkpoint_scanner", AsyncMock(return_value=dummy_scanner))
    monkeypatch.setattr(ServiceRegistry, "get_embedding_scanner", AsyncMock(return_value=dummy_scanner))

    monkeypatch.setattr(MetadataManager, "save_metadata", AsyncMock(return_value=True))

    result = await manager._execute_download(
        download_urls=download_urls,
        save_dir=str(save_dir),
        metadata=metadata,
        version_info=version_info,
        relative_path="",
        progress_callback=None,
        model_type="lora",
        download_id=None,
    )

    assert result == {"success": True}
    assert [url for url, *_ in dummy_downloader.calls] == download_urls
    assert dummy_scanner.calls  # ensure cache updated