import pytest
from fastapi.testclient import TestClient
from unittest.mock import patch
from constants import MAX_FILE_NAME_LENGTH
from main import app  # Adjust import based on your structure

client = TestClient(app)


def delete_with_body(url: str, json_data: dict):
    """Helper to send DELETE request with JSON body"""
    return client.request("DELETE", url, json=json_data)


class TestDeleteFileEndpoint:
    """Test the DELETE /file endpoint"""

    @pytest.fixture
    def base_required_fields(self):
        """Base fields required by IdentifierBase and ProfileBase"""
        return {
            "user_id": "test-user-123",
            "participant_id": "participant-456",
            "session_id": "test-session-123",
            "consent": True,
            "age_group": "25-34",
            "gender": "M",
            "roles": ["patient"],
        }

    @pytest.fixture
    def valid_payload(self, base_required_fields):
        return {**base_required_fields, "file_name": "document.txt"}

    @pytest.fixture
    def mock_dependencies(self):
        """Mock external dependencies"""
        with (
            patch("main.session_document_store") as mock_store,
            patch("main.replace_spaces_in_filename") as mock_replace,
        ):
            # Setup default behavior
            mock_replace.side_effect = lambda x: (
                x
            )  # Return filename unchanged by default
            mock_store.delete_document.return_value = True

            yield {"store": mock_store, "replace_spaces": mock_replace}

    # ==================== Successful Deletion Tests ====================

    def test_successful_file_deletion(self, valid_payload, mock_dependencies):
        """Test successful file deletion with valid inputs"""
        response = delete_with_body("/file", valid_payload)

        assert response.status_code == 200

        # Verify workflow
        mock_dependencies["replace_spaces"].assert_called_once_with("document.txt")
        mock_dependencies["store"].delete_document.assert_called_once_with(
            "test-session-123", "document.txt"
        )

    def test_delete_file_with_spaces_in_filename(
        self, base_required_fields, mock_dependencies
    ):
        """Test that spaces in filename are replaced"""
        payload = {**base_required_fields, "file_name": "my document.txt"}

        # Mock replace_spaces to return expected result
        mock_dependencies["replace_spaces"].side_effect = None
        mock_dependencies["replace_spaces"].return_value = "my_document.txt"

        response = delete_with_body("/file", payload)

        assert response.status_code == 200
        mock_dependencies["replace_spaces"].assert_called_once_with("my document.txt")
        mock_dependencies["store"].delete_document.assert_called_once_with(
            "test-session-123", "my_document.txt"
        )

    def test_delete_file_different_filenames(
        self, base_required_fields, mock_dependencies
    ):
        """Test deleting files with various filename formats"""
        filenames = [
            "document.txt",
            "report.pdf",
            "data.csv",
            "file_with_underscores.docx",
            "file-with-dashes.xlsx",
            "file.multiple.dots.txt",
        ]

        for filename in filenames:
            payload = {**base_required_fields, "file_name": filename}

            response = delete_with_body("/file", payload)
            assert response.status_code == 200

    def test_delete_file_different_session_ids(
        self, base_required_fields, mock_dependencies
    ):
        """Test deleting files from different sessions"""
        session_ids = [
            "session-1",
            "session-2",
            "session_abc_123",
            "a1b2c3",
        ]

        for session_id in session_ids:
            payload = {
                **base_required_fields,
                "session_id": session_id,
                "file_name": "document.txt",
            }

            response = delete_with_body("/file", payload)
            assert response.status_code == 200

    # ==================== Request Validation Tests ====================

    def test_delete_file_missing_session_id(
        self, base_required_fields, mock_dependencies
    ):
        """Test that missing session_id returns validation error"""
        payload = {**base_required_fields, "file_name": "document.txt"}
        del payload["session_id"]

        response = delete_with_body("/file", payload)

        assert response.status_code == 422
        # Store should not be called
        assert not mock_dependencies["store"].delete_document.called

    def test_delete_file_missing_file_name(
        self, base_required_fields, mock_dependencies
    ):
        """Test that missing file_name returns validation error"""
        payload = {**base_required_fields}

        response = delete_with_body("/file", payload)

        assert response.status_code == 422
        assert not mock_dependencies["store"].delete_document.called

    def test_delete_file_missing_both_fields(self, mock_dependencies):
        """Test that missing session_id and file_name returns validation error"""
        payload = {
            "user_id": "test-user",
            "participant_id": "participant-123",
            "consent": True,
            "age_group": "25-34",
            "gender": "M",
            "roles": ["patient"],
        }

        response = delete_with_body("/file", payload)

        assert response.status_code == 422
        assert not mock_dependencies["store"].delete_document.called

    def test_delete_file_empty_session_id(
        self, base_required_fields, mock_dependencies
    ):
        """Test handling of empty session_id"""
        payload = {
            **base_required_fields,
            "session_id": "",
            "file_name": "document.txt",
        }

        response = delete_with_body("/file", payload)

        # Empty string violates pattern and min_length
        assert response.status_code == 422

    def test_delete_file_empty_file_name(self, base_required_fields, mock_dependencies):
        """Test handling of empty file_name"""
        payload = {**base_required_fields, "file_name": ""}

        response = delete_with_body("/file", payload)

        # Empty string violates min_length=1
        assert response.status_code == 422

    def test_delete_file_extra_fields_ignored(
        self, base_required_fields, mock_dependencies
    ):
        """Test that extra fields in payload are ignored"""
        payload = {
            **base_required_fields,
            "file_name": "document.txt",
            "extra_field": "should be ignored",
            "another_field": 123,
        }

        response = delete_with_body("/file", payload)

        assert response.status_code == 200
        mock_dependencies["store"].delete_document.assert_called_once()

    # ==================== Store Behavior Tests ====================

    def test_delete_file_store_returns_true(self, valid_payload, mock_dependencies):
        """Test when store successfully deletes (returns True)"""
        mock_dependencies["store"].delete_document.return_value = True

        response = delete_with_body("/file", valid_payload)

        assert response.status_code == 200

    def test_delete_file_store_returns_false(self, valid_payload, mock_dependencies):
        """Test when store deletion fails (returns False)"""
        mock_dependencies["store"].delete_document.return_value = False

        response = delete_with_body("/file", valid_payload)

        # Endpoint doesn't check return value, so still 200
        assert response.status_code == 200

    def test_delete_file_nonexistent_file(
        self, base_required_fields, mock_dependencies
    ):
        """Test deleting a file that doesn't exist"""
        payload = {**base_required_fields, "file_name": "nonexistent.txt"}

        # Store returns False for nonexistent file
        mock_dependencies["store"].delete_document.return_value = False

        response = delete_with_body("/file", payload)

        # Endpoint still returns 200 (idempotent DELETE)
        assert response.status_code == 200

    def test_delete_file_nonexistent_session(
        self, base_required_fields, mock_dependencies
    ):
        """Test deleting from a session that doesn't exist"""
        payload = {
            **base_required_fields,
            "session_id": "nonexistent-session",
            "file_name": "document.txt",
        }

        mock_dependencies["store"].delete_document.return_value = False

        response = delete_with_body("/file", payload)

        assert response.status_code == 200

    # ==================== Filename Replacement Tests ====================

    def test_replace_spaces_called_with_correct_argument(
        self, base_required_fields, mock_dependencies
    ):
        """Test that replace_spaces_in_filename is called with the right argument"""
        payload = {**base_required_fields, "file_name": "my file.txt"}

        delete_with_body("/file", payload)

        mock_dependencies["replace_spaces"].assert_called_once_with("my file.txt")

    # ==================== Rate Limiting Tests ====================

    def test_invalid_filename_pattern_double_dots(
        self, base_required_fields, mock_dependencies
    ):
        """Test that filenames with double dots are rejected"""
        payload = {**base_required_fields, "file_name": "file..txt"}

        response = delete_with_body("/file", payload)
        assert response.status_code == 422

    def test_invalid_filename_pattern_starting_dot(
        self, base_required_fields, mock_dependencies
    ):
        """Test that filenames starting with dot are rejected"""
        payload = {**base_required_fields, "file_name": ".hidden.txt"}

        response = delete_with_body("/file", payload)
        assert response.status_code == 422

    def test_invalid_filename_pattern_starting_space(
        self, base_required_fields, mock_dependencies
    ):
        """Test that filenames starting with space are rejected"""
        payload = {**base_required_fields, "file_name": " file.txt"}

        response = delete_with_body("/file", payload)
        assert response.status_code == 422

    def test_valid_filename_with_parentheses(
        self, base_required_fields, mock_dependencies
    ):
        """Test that filenames with parentheses are accepted"""
        payload = {**base_required_fields, "file_name": "file(1).txt"}

        response = delete_with_body("/file", payload)
        assert response.status_code == 200

    def test_invalid_session_id_with_special_chars(
        self, base_required_fields, mock_dependencies
    ):
        """Test that session IDs with invalid characters are rejected"""
        invalid_ids = ["session@123", "session.123", "session/123", "session 123"]

        for invalid_id in invalid_ids:
            payload = {
                **base_required_fields,
                "session_id": invalid_id,
                "file_name": "document.txt",
            }

            response = delete_with_body("/file", payload)
            assert response.status_code == 422

    def test_invalid_age_group(self, base_required_fields, mock_dependencies):
        """Test that invalid age groups are rejected"""
        payload = {
            **base_required_fields,
            "age_group": "99-100",  # Invalid
            "file_name": "document.txt",
        }

        response = delete_with_body("/file", payload)
        assert response.status_code == 422

    def test_invalid_gender(self, base_required_fields, mock_dependencies):
        """Test that invalid gender values are rejected"""
        payload = {
            **base_required_fields,
            "gender": "X",  # Invalid - must be M or F
            "file_name": "document.txt",
        }

        response = delete_with_body("/file", payload)
        assert response.status_code == 422

    def test_missing_consent(self, base_required_fields, mock_dependencies):
        """Test that missing consent field is rejected"""
        payload = {**base_required_fields, "file_name": "document.txt"}
        del payload["consent"]

        response = delete_with_body("/file", payload)
        assert response.status_code == 422

    def test_invalid_roles_empty_set(self, base_required_fields, mock_dependencies):
        """Test that empty roles set is rejected"""
        payload = {
            **base_required_fields,
            "roles": [],  # Empty - violates min_length=1
            "file_name": "document.txt",
        }

        response = delete_with_body("/file", payload)
        assert response.status_code == 422

    def test_invalid_roles_too_many(self, base_required_fields, mock_dependencies):
        """Test that more than 5 roles is rejected"""
        payload = {
            **base_required_fields,
            "roles": [
                "patient",
                "clinician",
                "computer-scientist",
                "researcher",
                "other",
                "extra",
            ],
            "file_name": "document.txt",
        }

        response = delete_with_body("/file", payload)
        assert response.status_code == 422

    def test_invalid_role_value(self, base_required_fields, mock_dependencies):
        """Test that invalid role values are rejected"""
        payload = {
            **base_required_fields,
            "roles": ["invalid-role"],
            "file_name": "document.txt",
        }

        response = delete_with_body("/file", payload)
        assert response.status_code == 422

    def test_valid_multiple_roles(self, base_required_fields, mock_dependencies):
        """Test that multiple valid roles are accepted"""
        payload = {
            **base_required_fields,
            "roles": ["patient", "clinician", "researcher"],
            "file_name": "document.txt",
        }

        response = delete_with_body("/file", payload)
        assert response.status_code == 200

    # ==================== Rate Limiting Tests ====================

    @pytest.mark.enable_rate_limit
    def test_rate_limiting(self, valid_payload, mock_dependencies):
        """Test that rate limiting works (20 requests per minute)"""
        from fastapi.testclient import TestClient
        from main import app

        # Create fresh client with rate limiting enabled
        rate_limit_client = TestClient(app)

        # Make 21 rapid requests
        responses = []
        for i in range(21):
            response = rate_limit_client.request("DELETE", "/file", json=valid_payload)
            responses.append(response)

        # First 20 should succeed
        # 21st should be rate limited
        assert responses[-1].status_code == 429

    # ==================== Integration Tests ====================

    def test_delete_same_file_twice_idempotent(self, valid_payload, mock_dependencies):
        """Test that deleting the same file twice is idempotent"""
        # First delete
        response1 = delete_with_body("/file", valid_payload)
        assert response1.status_code == 200

        # Second delete (file already gone)
        mock_dependencies["store"].delete_document.return_value = False
        response2 = delete_with_body("/file", valid_payload)
        assert response2.status_code == 200

    def test_delete_multiple_files_same_session(
        self, base_required_fields, mock_dependencies
    ):
        """Test deleting multiple files from the same session"""
        session_id = "test-session"
        files = ["file1.txt", "file2.txt", "file3.txt"]

        for filename in files:
            payload = {
                **base_required_fields,
                "session_id": session_id,
                "file_name": filename,
            }

            response = delete_with_body("/file", payload)
            assert response.status_code == 200

    def test_delete_files_from_multiple_sessions(
        self, base_required_fields, mock_dependencies
    ):
        """Test deleting files from different sessions"""
        sessions_and_files = [
            ("session-1", "file1.txt"),
            ("session-2", "file2.txt"),
            ("session-3", "file3.txt"),
        ]

        for session_id, filename in sessions_and_files:
            payload = {
                **base_required_fields,
                "session_id": session_id,
                "file_name": filename,
            }

            response = delete_with_body("/file", payload)
            assert response.status_code == 200

    def test_workflow_order(self, valid_payload, mock_dependencies):
        """Test that operations happen in correct order"""
        call_order = []

        def track_replace(filename):
            call_order.append("replace")
            return filename

        def track_delete(session_id, filename):
            call_order.append("delete")
            return True

        mock_dependencies["replace_spaces"].side_effect = track_replace
        mock_dependencies["store"].delete_document.side_effect = track_delete

        delete_with_body("/file", valid_payload)

        # replace_spaces should be called before delete_document
        assert call_order == ["replace", "delete"]

    def test_very_long_filename(self, base_required_fields, mock_dependencies):
        """Test handling of very long filenames"""
        long_filename = "a" * MAX_FILE_NAME_LENGTH + ".txt"
        payload = {**base_required_fields, "file_name": long_filename}

        response = delete_with_body("/file", payload)

        assert response.status_code == 422

    def test_very_long_session_id(self, base_required_fields, mock_dependencies):
        """Test handling of very long session IDs"""
        long_session_id = "s" * 51
        payload = {
            **base_required_fields,
            "session_id": long_session_id,
            "file_name": "document.txt",
        }

        response = delete_with_body("/file", payload)

        assert response.status_code == 422