"""
Tests for S3StorageBackend.

TDD Phase 1: RED - Write tests first, then implement to pass.
"""

import shutil
import tempfile
from pathlib import Path
from unittest.mock import MagicMock, patch, call

import pytest


@pytest.fixture
def temp_dir() -> Path:
    """Create a temporary directory for tests."""
    temp_dir = Path(tempfile.mkdtemp())
    yield temp_dir
    shutil.rmtree(temp_dir, ignore_errors=True)


@pytest.fixture
def sample_file(temp_dir: Path) -> Path:
    """Create a sample file for testing."""
    file_path = temp_dir / "sample.txt"
    file_path.write_text("Hello, World!")
    return file_path


@pytest.fixture
def mock_boto3_client():
    """Create a mock boto3 S3 client."""
    with patch("boto3.client") as mock_client_func:
        mock_client = MagicMock()
        mock_client_func.return_value = mock_client
        yield mock_client


class TestS3StorageBackendCreation:
    """Tests for S3StorageBackend instantiation."""

    def test_create_with_bucket_name(self, mock_boto3_client: MagicMock) -> None:
        """Test creating backend with bucket name."""
        from shared.storage.s3 import S3StorageBackend

        backend = S3StorageBackend(bucket_name="test-bucket")

        assert backend.bucket_name == "test-bucket"

    def test_create_with_region(self, mock_boto3_client: MagicMock) -> None:
        """Test creating backend with region."""
        from shared.storage.s3 import S3StorageBackend

        with patch("boto3.client") as mock_client:
            S3StorageBackend(
                bucket_name="test-bucket",
                region_name="us-west-2",
            )

            mock_client.assert_called_once()
            call_kwargs = mock_client.call_args[1]
            assert call_kwargs.get("region_name") == "us-west-2"

    def test_create_with_credentials(self, mock_boto3_client: MagicMock) -> None:
        """Test creating backend with explicit credentials."""
        from shared.storage.s3 import S3StorageBackend

        with patch("boto3.client") as mock_client:
            S3StorageBackend(
                bucket_name="test-bucket",
                access_key_id="AKIATEST",
                secret_access_key="secret123",
            )

            mock_client.assert_called_once()
            call_kwargs = mock_client.call_args[1]
            assert call_kwargs.get("aws_access_key_id") == "AKIATEST"
            assert call_kwargs.get("aws_secret_access_key") == "secret123"

    def test_create_with_endpoint_url(self, mock_boto3_client: MagicMock) -> None:
        """Test creating backend with custom endpoint (for S3-compatible services)."""
        from shared.storage.s3 import S3StorageBackend

        with patch("boto3.client") as mock_client:
            S3StorageBackend(
                bucket_name="test-bucket",
                endpoint_url="http://localhost:9000",
            )

            mock_client.assert_called_once()
            call_kwargs = mock_client.call_args[1]
            assert call_kwargs.get("endpoint_url") == "http://localhost:9000"

    def test_create_bucket_when_requested(self, mock_boto3_client: MagicMock) -> None:
        """Test that bucket is created when create_bucket=True."""
        from botocore.exceptions import ClientError
        from shared.storage.s3 import S3StorageBackend

        mock_boto3_client.head_bucket.side_effect = ClientError(
            {"Error": {"Code": "404"}}, "HeadBucket"
        )

        S3StorageBackend(
            bucket_name="test-bucket",
            create_bucket=True,
        )

        mock_boto3_client.create_bucket.assert_called_once()

    def test_is_storage_backend_subclass(self, mock_boto3_client: MagicMock) -> None:
        """Test that S3StorageBackend is a StorageBackend."""
        from shared.storage.base import StorageBackend
        from shared.storage.s3 import S3StorageBackend

        backend = S3StorageBackend(bucket_name="test-bucket")

        assert isinstance(backend, StorageBackend)


class TestS3StorageBackendUpload:
    """Tests for S3StorageBackend.upload method."""

    def test_upload_file(
        self, mock_boto3_client: MagicMock, temp_dir: Path, sample_file: Path
    ) -> None:
        """Test uploading a file."""
        from botocore.exceptions import ClientError
        from shared.storage.s3 import S3StorageBackend

        # Object does not exist
        mock_boto3_client.head_object.side_effect = ClientError(
            {"Error": {"Code": "404"}}, "HeadObject"
        )

        backend = S3StorageBackend(bucket_name="test-bucket")

        result = backend.upload(sample_file, "uploads/sample.txt")

        assert result == "uploads/sample.txt"
        mock_boto3_client.upload_file.assert_called_once()

    def test_upload_fails_if_exists_without_overwrite(
        self, mock_boto3_client: MagicMock, sample_file: Path
    ) -> None:
        """Test that upload fails if object exists and overwrite is False."""
        from shared.storage.base import StorageError
        from shared.storage.s3 import S3StorageBackend

        mock_boto3_client.head_object.return_value = {}  # Object exists

        backend = S3StorageBackend(bucket_name="test-bucket")

        with pytest.raises(StorageError, match="already exists"):
            backend.upload(sample_file, "sample.txt", overwrite=False)

    def test_upload_succeeds_with_overwrite(
        self, mock_boto3_client: MagicMock, sample_file: Path
    ) -> None:
        """Test that upload succeeds with overwrite=True."""
        from shared.storage.s3 import S3StorageBackend

        mock_boto3_client.head_object.return_value = {}  # Object exists

        backend = S3StorageBackend(bucket_name="test-bucket")
        result = backend.upload(sample_file, "sample.txt", overwrite=True)

        assert result == "sample.txt"
        mock_boto3_client.upload_file.assert_called_once()

    def test_upload_nonexistent_file_fails(
        self, mock_boto3_client: MagicMock, temp_dir: Path
    ) -> None:
        """Test that uploading nonexistent file fails."""
        from shared.storage.base import FileNotFoundStorageError
        from shared.storage.s3 import S3StorageBackend

        backend = S3StorageBackend(bucket_name="test-bucket")

        with pytest.raises(FileNotFoundStorageError):
            backend.upload(temp_dir / "nonexistent.txt", "sample.txt")


class TestS3StorageBackendDownload:
    """Tests for S3StorageBackend.download method."""

    def test_download_file(
        self, mock_boto3_client: MagicMock, temp_dir: Path
    ) -> None:
        """Test downloading a file."""
        from shared.storage.s3 import S3StorageBackend

        mock_boto3_client.head_object.return_value = {}  # Object exists

        backend = S3StorageBackend(bucket_name="test-bucket")
        local_path = temp_dir / "downloaded.txt"

        result = backend.download("sample.txt", local_path)

        assert result == local_path
        mock_boto3_client.download_file.assert_called_once()

    def test_download_creates_parent_directories(
        self, mock_boto3_client: MagicMock, temp_dir: Path
    ) -> None:
        """Test that download creates parent directories."""
        from shared.storage.s3 import S3StorageBackend

        mock_boto3_client.head_object.return_value = {}

        backend = S3StorageBackend(bucket_name="test-bucket")
        local_path = temp_dir / "deep" / "nested" / "downloaded.txt"

        backend.download("sample.txt", local_path)

        assert local_path.parent.exists()

    def test_download_nonexistent_object_fails(
        self, mock_boto3_client: MagicMock, temp_dir: Path
    ) -> None:
        """Test that downloading nonexistent object fails."""
        from botocore.exceptions import ClientError
        from shared.storage.base import FileNotFoundStorageError
        from shared.storage.s3 import S3StorageBackend

        mock_boto3_client.head_object.side_effect = ClientError(
            {"Error": {"Code": "404"}}, "HeadObject"
        )

        backend = S3StorageBackend(bucket_name="test-bucket")

        with pytest.raises(FileNotFoundStorageError):
            backend.download("nonexistent.txt", temp_dir / "file.txt")


class TestS3StorageBackendExists:
    """Tests for S3StorageBackend.exists method."""

    def test_exists_returns_true_for_existing_object(
        self, mock_boto3_client: MagicMock
    ) -> None:
        """Test exists returns True for existing object."""
        from shared.storage.s3 import S3StorageBackend

        mock_boto3_client.head_object.return_value = {}

        backend = S3StorageBackend(bucket_name="test-bucket")

        assert backend.exists("sample.txt") is True

    def test_exists_returns_false_for_nonexistent_object(
        self, mock_boto3_client: MagicMock
    ) -> None:
        """Test exists returns False for nonexistent object."""
        from botocore.exceptions import ClientError
        from shared.storage.s3 import S3StorageBackend

        mock_boto3_client.head_object.side_effect = ClientError(
            {"Error": {"Code": "404"}}, "HeadObject"
        )

        backend = S3StorageBackend(bucket_name="test-bucket")

        assert backend.exists("nonexistent.txt") is False


class TestS3StorageBackendListFiles:
    """Tests for S3StorageBackend.list_files method."""

    def test_list_files_returns_objects(
        self, mock_boto3_client: MagicMock
    ) -> None:
        """Test listing objects."""
        from shared.storage.s3 import S3StorageBackend

        mock_boto3_client.list_objects_v2.return_value = {
            "Contents": [
                {"Key": "file1.txt"},
                {"Key": "file2.txt"},
                {"Key": "subdir/file3.txt"},
            ]
        }

        backend = S3StorageBackend(bucket_name="test-bucket")
        files = backend.list_files("")

        assert len(files) == 3
        assert "file1.txt" in files
        assert "file2.txt" in files
        assert "subdir/file3.txt" in files

    def test_list_files_with_prefix(
        self, mock_boto3_client: MagicMock
    ) -> None:
        """Test listing objects with prefix filter."""
        from shared.storage.s3 import S3StorageBackend

        mock_boto3_client.list_objects_v2.return_value = {
            "Contents": [
                {"Key": "images/a.png"},
                {"Key": "images/b.png"},
            ]
        }

        backend = S3StorageBackend(bucket_name="test-bucket")
        files = backend.list_files("images/")

        mock_boto3_client.list_objects_v2.assert_called_with(
            Bucket="test-bucket", Prefix="images/"
        )

    def test_list_files_empty_bucket(
        self, mock_boto3_client: MagicMock
    ) -> None:
        """Test listing files in empty bucket."""
        from shared.storage.s3 import S3StorageBackend

        mock_boto3_client.list_objects_v2.return_value = {}  # No Contents key

        backend = S3StorageBackend(bucket_name="test-bucket")
        files = backend.list_files("")

        assert files == []


class TestS3StorageBackendDelete:
    """Tests for S3StorageBackend.delete method."""

    def test_delete_existing_object(
        self, mock_boto3_client: MagicMock
    ) -> None:
        """Test deleting an existing object."""
        from shared.storage.s3 import S3StorageBackend

        mock_boto3_client.head_object.return_value = {}

        backend = S3StorageBackend(bucket_name="test-bucket")
        result = backend.delete("sample.txt")

        assert result is True
        mock_boto3_client.delete_object.assert_called_once()

    def test_delete_nonexistent_object_returns_false(
        self, mock_boto3_client: MagicMock
    ) -> None:
        """Test deleting nonexistent object returns False."""
        from botocore.exceptions import ClientError
        from shared.storage.s3 import S3StorageBackend

        mock_boto3_client.head_object.side_effect = ClientError(
            {"Error": {"Code": "404"}}, "HeadObject"
        )

        backend = S3StorageBackend(bucket_name="test-bucket")
        result = backend.delete("nonexistent.txt")

        assert result is False


class TestS3StorageBackendGetUrl:
    """Tests for S3StorageBackend.get_url method."""

    def test_get_url_returns_s3_url(
        self, mock_boto3_client: MagicMock
    ) -> None:
        """Test get_url returns S3 URL."""
        from shared.storage.s3 import S3StorageBackend

        mock_boto3_client.head_object.return_value = {}
        mock_boto3_client.generate_presigned_url.return_value = (
            "https://test-bucket.s3.amazonaws.com/sample.txt"
        )

        backend = S3StorageBackend(bucket_name="test-bucket")
        url = backend.get_url("sample.txt")

        assert "sample.txt" in url

    def test_get_url_nonexistent_object_raises(
        self, mock_boto3_client: MagicMock
    ) -> None:
        """Test get_url raises for nonexistent object."""
        from botocore.exceptions import ClientError
        from shared.storage.base import FileNotFoundStorageError
        from shared.storage.s3 import S3StorageBackend

        mock_boto3_client.head_object.side_effect = ClientError(
            {"Error": {"Code": "404"}}, "HeadObject"
        )

        backend = S3StorageBackend(bucket_name="test-bucket")

        with pytest.raises(FileNotFoundStorageError):
            backend.get_url("nonexistent.txt")


class TestS3StorageBackendUploadBytes:
    """Tests for S3StorageBackend.upload_bytes method."""

    def test_upload_bytes(
        self, mock_boto3_client: MagicMock
    ) -> None:
        """Test uploading bytes directly."""
        from shared.storage.s3 import S3StorageBackend

        from botocore.exceptions import ClientError
        mock_boto3_client.head_object.side_effect = ClientError(
            {"Error": {"Code": "404"}}, "HeadObject"
        )

        backend = S3StorageBackend(bucket_name="test-bucket")
        data = b"Binary content here"

        result = backend.upload_bytes(data, "binary.dat")

        assert result == "binary.dat"
        mock_boto3_client.put_object.assert_called_once()

    def test_upload_bytes_fails_if_exists_without_overwrite(
        self, mock_boto3_client: MagicMock
    ) -> None:
        """Test upload_bytes fails if object exists and overwrite is False."""
        from shared.storage.base import StorageError
        from shared.storage.s3 import S3StorageBackend

        mock_boto3_client.head_object.return_value = {}  # Object exists

        backend = S3StorageBackend(bucket_name="test-bucket")

        with pytest.raises(StorageError, match="already exists"):
            backend.upload_bytes(b"content", "sample.txt", overwrite=False)


class TestS3StorageBackendDownloadBytes:
    """Tests for S3StorageBackend.download_bytes method."""

    def test_download_bytes(
        self, mock_boto3_client: MagicMock
    ) -> None:
        """Test downloading object as bytes."""
        from shared.storage.s3 import S3StorageBackend

        mock_response = MagicMock()
        mock_response.read.return_value = b"Hello, World!"
        mock_boto3_client.get_object.return_value = {"Body": mock_response}

        backend = S3StorageBackend(bucket_name="test-bucket")
        data = backend.download_bytes("sample.txt")

        assert data == b"Hello, World!"

    def test_download_bytes_nonexistent_raises(
        self, mock_boto3_client: MagicMock
    ) -> None:
        """Test downloading nonexistent object as bytes."""
        from botocore.exceptions import ClientError
        from shared.storage.base import FileNotFoundStorageError
        from shared.storage.s3 import S3StorageBackend

        mock_boto3_client.get_object.side_effect = ClientError(
            {"Error": {"Code": "NoSuchKey"}}, "GetObject"
        )

        backend = S3StorageBackend(bucket_name="test-bucket")

        with pytest.raises(FileNotFoundStorageError):
            backend.download_bytes("nonexistent.txt")


class TestS3StorageBackendPresignedUrl:
    """Tests for S3StorageBackend.get_presigned_url method."""

    def test_get_presigned_url_generates_url(
        self, mock_boto3_client: MagicMock
    ) -> None:
        """Test get_presigned_url generates presigned URL."""
        from shared.storage.s3 import S3StorageBackend

        mock_boto3_client.head_object.return_value = {}
        mock_boto3_client.generate_presigned_url.return_value = (
            "https://test-bucket.s3.amazonaws.com/sample.txt?X-Amz-Algorithm=..."
        )

        backend = S3StorageBackend(bucket_name="test-bucket")
        url = backend.get_presigned_url("sample.txt")

        assert "X-Amz-Algorithm" in url or "sample.txt" in url
        mock_boto3_client.generate_presigned_url.assert_called_once()

    def test_get_presigned_url_with_custom_expiry(
        self, mock_boto3_client: MagicMock
    ) -> None:
        """Test get_presigned_url uses custom expiry."""
        from shared.storage.s3 import S3StorageBackend

        mock_boto3_client.head_object.return_value = {}
        mock_boto3_client.generate_presigned_url.return_value = "https://..."

        backend = S3StorageBackend(bucket_name="test-bucket")
        backend.get_presigned_url("sample.txt", expires_in_seconds=7200)

        call_args = mock_boto3_client.generate_presigned_url.call_args
        assert call_args[1].get("ExpiresIn") == 7200

    def test_get_presigned_url_nonexistent_raises(
        self, mock_boto3_client: MagicMock
    ) -> None:
        """Test get_presigned_url raises for nonexistent object."""
        from botocore.exceptions import ClientError
        from shared.storage.base import FileNotFoundStorageError
        from shared.storage.s3 import S3StorageBackend

        mock_boto3_client.head_object.side_effect = ClientError(
            {"Error": {"Code": "404"}}, "HeadObject"
        )

        backend = S3StorageBackend(bucket_name="test-bucket")

        with pytest.raises(FileNotFoundStorageError):
            backend.get_presigned_url("nonexistent.txt")