"""Error path tests for API and sync operations.

Additional comprehensive error testing for:
- API request/response errors
- Sync operation failures
- Network timeouts
- Data serialization errors
- Transaction rollback scenarios
"""

import asyncio
import json
import pathlib
from datetime import UTC, datetime
from typing import Any, Never
from unittest.mock import AsyncMock, MagicMock, patch

import pytest
from sqlalchemy.exc import IntegrityError
from sqlalchemy.ext.asyncio import AsyncSession

from tests.test_constants import COUNT_TWO, HTTP_INTERNAL_SERVER_ERROR
from tracertm.api.client import TraceRTMClient
from tracertm.models.item import Item
from tracertm.repositories.item_repository import ItemRepository

# ============================================================================
# API CLIENT ERROR TESTS
# ============================================================================


class TestAPIClientErrors:
    """Test error handling in API client."""

    def test_api_request_with_none_response(self) -> None:
        """Test API request that returns None."""
        client = TraceRTMClient()

        with (
            patch.object(client, "_get_session", return_value=None),
            pytest.raises((ValueError, AttributeError, TypeError)),
        ):
            client._get_session()

    def test_api_timeout_handling(self) -> None:
        """Test handling of API timeout."""

        async def slow_api_call() -> None:
            await asyncio.sleep(10)

        with pytest.raises(asyncio.TimeoutError):
            asyncio.run(asyncio.wait_for(slow_api_call(), timeout=0.01))

    def test_api_500_error_response(self) -> None:
        """Test handling of 500 error response."""
        with patch("requests.get") as mock_get:
            mock_response = MagicMock()
            mock_response.status_code = 500
            mock_response.text = "Internal Server Error"
            mock_get.return_value = mock_response

            # Test behavior when encountering 500
            assert mock_response.status_code == HTTP_INTERNAL_SERVER_ERROR

    def test_api_malformed_json_response(self) -> None:
        """Test handling of malformed JSON in response."""
        with patch("requests.get") as mock_get:
            mock_response = MagicMock()
            mock_response.json.side_effect = json.JSONDecodeError("Invalid JSON", "", 0)
            mock_get.return_value = mock_response

            with pytest.raises(json.JSONDecodeError):
                mock_response.json()

    def test_api_missing_required_field(self) -> None:
        """Test API response missing required field."""
        response = {"name": "Test"}  # Missing 'id' field

        # Validation should catch this
        with pytest.raises((KeyError, ValueError)):
            response["id"]  # KeyError

    def test_api_invalid_data_type(self) -> None:
        """Test API response with invalid data type."""
        response = {"id": "item-1", "count": "not-a-number"}  # Invalid type

        with pytest.raises((ValueError, TypeError)):
            int(response["count"])


# ============================================================================
# SYNC OPERATION ERROR TESTS
# ============================================================================


@pytest.mark.asyncio
class TestSyncOperationErrors:
    """Test error handling in sync operations."""

    async def test_sync_with_network_error(self) -> None:
        """Test sync when network error occurs."""

        async def network_operation() -> Never:
            await asyncio.sleep(0)
            msg = "Network unreachable"
            raise ConnectionError(msg)

        with pytest.raises(ConnectionError):
            await network_operation()

    async def test_sync_with_timeout(self) -> None:
        """Test sync operation timeout."""

        async def slow_sync() -> None:
            await asyncio.sleep(10)

        with pytest.raises(asyncio.TimeoutError):
            await asyncio.wait_for(slow_sync(), timeout=0.01)

    async def test_sync_partial_update_failure(self, db_session: AsyncSession) -> None:
        """Test sync fails partway through updates."""
        repo = ItemRepository(db_session)

        # Create first item successfully
        item1 = await repo.create(
            project_id="project-1",
            title="Item 1",
            view="board",
            item_type="requirement",
        )

        # Second update fails
        with patch.object(repo.session, "flush", side_effect=RuntimeError("Update failed")):
            item2 = Item(
                id="item-2",
                project_id="project-1",
                title="Item 2",
                view="board",
                item_type="requirement",
            )
            repo.session.add(item2)

            with pytest.raises(RuntimeError, match="Update failed"):
                await repo.session.flush()

        # First item should exist
        retrieved = await repo.get_by_id(str(item1.id))
        assert retrieved is not None

    async def test_sync_rollback_on_error(self, _db_session: AsyncSession) -> None:
        """Test that sync changes are rolled back on error."""
        mock_session = AsyncMock(spec=AsyncSession)
        mock_session.begin = AsyncMock()
        mock_session.commit = AsyncMock()
        mock_session.rollback = AsyncMock()

        # Simulate error during flush
        mock_session.flush = AsyncMock(side_effect=RuntimeError("Flush failed"))

        repo = ItemRepository(mock_session)

        with pytest.raises(RuntimeError, match="Flush failed"):
            await repo.session.flush()

    async def test_sync_duplicate_key_error(self, db_session: AsyncSession) -> None:
        """Test handling of duplicate key in sync."""
        repo = ItemRepository(db_session)

        # Create item
        item1 = await repo.create(
            project_id="project-1",
            title="Item",
            view="board",
            item_type="requirement",
        )

        # Try to create with same ID
        item2 = Item(
            id=item1.id,  # Duplicate ID
            project_id="project-1",
            title="Item 2",
            view="board",
            item_type="requirement",
        )

        db_session.add(item2)

        with pytest.raises((IntegrityError, Exception)):
            await db_session.flush()

    async def test_sync_foreign_key_violation(self, db_session: AsyncSession) -> None:
        """Test handling of foreign key violation in sync."""

        # Try to create item with non-existent project
        def add_invalid_item() -> None:
            item = Item(
                id="item-1",
                project_id="non-existent-project",
                title="Item",
                view="board",
                item_type="requirement",
            )
            db_session.add(item)
            return item

        async def flush_invalid() -> None:
            add_invalid_item()
            await db_session.flush()

        with pytest.raises((IntegrityError, ValueError)):
            await flush_invalid()

    async def test_sync_concurrent_modification(self, db_session: AsyncSession) -> None:
        """Test handling of concurrent modification during sync."""
        repo = ItemRepository(db_session)

        item = await repo.create(
            project_id="project-1",
            title="Item",
            view="board",
            item_type="requirement",
        )

        # Simulate concurrent modification by raising version conflict
        with patch.object(
            db_session,
            "flush",
            side_effect=RuntimeError("Concurrent modification"),
        ):
            item.title = "Updated"

            with pytest.raises(RuntimeError, match="Concurrent modification"):
                await db_session.flush()


# ============================================================================
# TRANSACTION ERROR TESTS
# ============================================================================


@pytest.mark.asyncio
class TestTransactionErrors:
    """Test transaction and ACID property errors."""

    async def test_transaction_commit_failure(self) -> None:
        """Test handling of commit failure."""
        mock_session = AsyncMock()
        mock_session.commit = AsyncMock(side_effect=RuntimeError("Commit failed"))

        with pytest.raises(RuntimeError, match="Commit failed"):
            await mock_session.commit()

    async def test_transaction_rollback_failure(self) -> None:
        """Test handling of rollback failure."""
        mock_session = AsyncMock()
        mock_session.rollback = AsyncMock(side_effect=RuntimeError("Rollback failed"))

        with pytest.raises(RuntimeError, match="Rollback failed"):
            await mock_session.rollback()

    async def test_nested_transaction_error(self) -> None:
        """Test error in nested transaction."""
        mock_session = AsyncMock()
        mock_session.begin = AsyncMock()
        mock_session.begin_nested = AsyncMock()
        mock_session.flush = AsyncMock(side_effect=RuntimeError("Nested flush failed"))

        async def do_flush() -> None:
            async with mock_session.begin_nested():
                await mock_session.flush()

        with pytest.raises(RuntimeError, match="Nested flush failed"):
            await do_flush()

    async def test_deadlock_detection(self) -> Never:
        """Test detection of database deadlock."""
        # Simulate deadlock
        with pytest.raises(RuntimeError, match="Deadlock detected"):
            msg = "Deadlock detected"
            raise RuntimeError(msg)

    async def test_lock_wait_timeout(self) -> None:
        """Test lock wait timeout."""

        async def lock_operation() -> None:
            await asyncio.sleep(10)

        with pytest.raises(asyncio.TimeoutError):
            await asyncio.wait_for(lock_operation(), timeout=0.01)


# ============================================================================
# DATA SERIALIZATION ERROR TESTS
# ============================================================================


class TestDataSerializationErrors:
    """Test error handling in data serialization."""

    def test_json_serialization_circular_reference(self) -> None:
        """Test JSON serialization with circular reference."""

        # Intentional plain class for circular self-ref; dataclass cannot express it
        class CircularObj:
            def __init__(self) -> None:
                self.ref = self

        obj = CircularObj()

        with pytest.raises((ValueError, TypeError)):
            json.dumps(obj, default=str)

    def test_json_serialization_non_serializable_type(self) -> None:
        """Test JSON serialization with non-serializable type."""
        data = {"date": datetime.now(UTC)}  # datetime not JSON serializable

        with pytest.raises(TypeError):
            json.dumps(data)

    def test_json_deserialization_invalid_utf8(self) -> None:
        """Test JSON deserialization with invalid UTF-8."""
        invalid_json = b"\x80\x81\x82"  # Invalid UTF-8

        with pytest.raises((json.JSONDecodeError, UnicodeDecodeError)):
            json.loads(invalid_json.decode("utf-8", errors="strict"))

    def test_json_deserialization_truncated_json(self) -> None:
        """Test JSON deserialization with truncated JSON."""
        truncated = '{"key": "va'  # Incomplete JSON

        with pytest.raises(json.JSONDecodeError):
            json.loads(truncated)

    def test_dict_to_model_type_mismatch(self) -> None:
        """Test converting dict to model with type mismatch."""
        data = {
            "id": "item-1",
            "project_id": "project-1",
            "title": "Test",
            "view": "board",
            "item_type": "requirement",
            "version": "not-a-number",  # Should be int
        }

        # Behavior depends on model validation (may raise or coerce)
        try:
            Item(**data)
        except (ValueError, TypeError):
            pass

    def test_model_to_dict_with_none_values(self) -> None:
        """Test converting model with None values to dict."""
        item = Item(
            id="item-1",
            project_id="project-1",
            title="Test",
            view="board",
            item_type="requirement",
            description=None,
            parent_id=None,
        )

        item_dict = {
            "id": item.id,
            "project_id": item.project_id,
            "title": item.title,
            "view": item.view,
            "item_type": item.item_type,
            "description": item.description,
            "parent_id": item.parent_id,
        }

        # None values should be preserved
        assert item_dict["description"] is None


# ============================================================================
# RESOURCE LIMIT ERROR TESTS
# ============================================================================


@pytest.mark.asyncio
class TestResourceLimitErrors:
    """Test handling of resource limit errors."""

    async def test_memory_exhaustion_large_list(self) -> None:
        """Test handling of large list that might exhaust memory."""
        # Create large list in controlled way
        try:
            large_list = list(range(1000000))
            assert len(large_list) == 1000000
        except MemoryError:
            pytest.skip("System out of memory")

    async def test_database_connection_pool_exhaustion(self) -> None:
        """Test handling of exhausted connection pool."""
        from sqlalchemy import create_engine

        with (
            patch(
                "sqlalchemy.create_engine",
                side_effect=RuntimeError("No connection available"),
            ),
            pytest.raises(RuntimeError, match="No connection available"),
        ):
            create_engine("sqlite:///:memory:")

    async def test_file_descriptor_exhaustion(self) -> None:
        """Test handling of exhausted file descriptors."""
        with (
            patch(
                "builtins.open",
                side_effect=OSError("Too many open files"),
            ),
            pytest.raises(OSError, match="Too many open files"),
        ):
            pathlib.Path("/dev/null").open(encoding="utf-8").close()

    async def test_request_queue_full(self) -> None:
        """Test handling of full request queue."""
        queue = asyncio.Queue(maxsize=1)

        # Fill queue
        await queue.put("item1")

        # Try to add when full should block or raise
        try:
            queue.put_nowait("item2")
        except asyncio.QueueFull:
            pass  # Expected


# ============================================================================
# CACHE AND OPTIMIZATION ERROR TESTS
# ============================================================================


class TestCacheErrors:
    """Test error handling in caching mechanisms."""

    def test_cache_invalidation_error(self) -> None:
        """Test error during cache invalidation."""

        def invalidate_cache() -> Never:
            msg = "Cache invalidation failed"
            raise RuntimeError(msg)

        with pytest.raises(RuntimeError, match="Cache invalidation failed"):
            invalidate_cache()

    def test_stale_cache_data(self) -> None:
        """Test handling of stale cache data."""
        cache = {"key": "stale_value"}
        current_value = "current_value"

        if cache["key"] != current_value:
            # Cache is stale
            cache["key"] = current_value

        assert cache["key"] == current_value

    def test_cache_hit_with_exception(self) -> None:
        """Test cache hit when accessing throws exception."""
        cache = {"key": {"data": None}}

        with pytest.raises((KeyError, TypeError, AttributeError)):
            _ = cache["key"]["nonexistent_field"]


# ============================================================================
# LOGGING ERROR TESTS
# ============================================================================


class TestLoggingErrors:
    """Test error handling in logging operations."""

    def test_log_with_invalid_level(self) -> None:
        """Test logging with invalid log level."""
        import logging

        logger = logging.getLogger(__name__)

        with pytest.raises((ValueError, AttributeError)):
            logger.log(999, "Message")  # Invalid level

    def test_log_with_unprintable_characters(self) -> None:
        """Test logging with unprintable characters."""
        import logging

        logger = logging.getLogger(__name__)

        # Should handle gracefully
        logger.warning("Message with \x00 null bytes")
        logger.error("Message with \x80\x81 invalid utf8")

    def test_log_file_write_failure(self) -> None:
        """Test handling of log file write failure."""
        with (
            patch("builtins.open", side_effect=OSError("Write failed")),
            pytest.raises(OSError, match="Write failed"),
        ):
            pathlib.Path("logfile.log").write_text("message", encoding="utf-8")

    def test_log_formatter_error(self) -> None:
        """Test error in log formatter."""
        import logging

        class FailingFormatter(logging.Formatter):
            def format(self, _record: Any) -> Never:
                msg = "Formatting failed"
                raise RuntimeError(msg)

        logger = logging.getLogger(__name__)
        handler = logging.StreamHandler()
        handler.setFormatter(FailingFormatter())
        logger.addHandler(handler)

        with pytest.raises(RuntimeError, match="Formatting failed"):
            logger.info("Message")


# ============================================================================
# EVENT HANDLING ERROR TESTS
# ============================================================================


@pytest.mark.asyncio
class TestEventHandlingErrors:
    """Test error handling in event systems."""

    async def test_event_listener_exception(self) -> None:
        """Test handling when event listener raises exception."""
        listeners = []

        def register_listener(callback: Any) -> None:
            listeners.append(callback)

        def emit_event(data: Any) -> None:
            for listener in listeners:
                listener(data)

        def failing_listener(_data: Any) -> Never:
            msg = "Listener failed"
            raise RuntimeError(msg)

        register_listener(failing_listener)

        with pytest.raises(RuntimeError, match="Listener failed"):
            emit_event({"type": "test"})

    async def test_event_queue_overflow(self) -> None:
        """Test handling of event queue overflow."""
        event_queue = asyncio.Queue(maxsize=1)

        await event_queue.put({"type": "event1"})

        with pytest.raises(asyncio.QueueFull):
            event_queue.put_nowait({"type": "event2"})

    async def test_event_ordering_error(self) -> None:
        """Test error when events are processed out of order."""
        events = []
        expected_order = [1, 2, 3]

        events.extend((1, 3, 2))

        if events != expected_order:
            # Events out of order
            events.sort()

        assert events == expected_order


# ============================================================================
# VALIDATION ERROR TESTS
# ============================================================================


class TestValidationErrors:
    """Test validation error handling."""

    def test_required_field_validation(self) -> None:
        """Test validation of required fields."""

        def validate_item(data: Any) -> None:
            if not data.get("title"):
                msg = "title is required"
                raise ValueError(msg)

        with pytest.raises(ValueError, match="title is required"):
            validate_item({})

    def test_constraint_violation(self) -> None:
        """Test constraint validation."""

        def validate_priority(priority: Any) -> None:
            valid_priorities = ["low", "medium", "high"]
            if priority not in valid_priorities:
                msg = f"priority must be one of {valid_priorities}"
                raise ValueError(msg)

        with pytest.raises(ValueError, match="priority must be"):
            validate_priority("invalid")

    def test_range_validation(self) -> None:
        """Test range validation."""

        def validate_version(version: Any) -> None:
            if not (1 <= version <= 1000):
                msg = "version must be between 1 and 1000"
                raise ValueError(msg)

        with pytest.raises(ValueError, match="version must be"):
            validate_version(2000)

    def test_format_validation(self) -> None:
        """Test format validation."""

        def validate_email(email: Any) -> None:
            if "@" not in email:
                msg = "Invalid email format"
                raise ValueError(msg)

        with pytest.raises(ValueError, match="Invalid email"):
            validate_email("invalid-email")

    def test_regex_validation_error(self) -> None:
        """Test regex validation error."""
        import re

        def validate_pattern(value: Any, pattern: Any) -> None:
            if not re.match(pattern, value):
                msg = f"Value does not match pattern {pattern}"
                raise ValueError(msg)

        with pytest.raises(ValueError, match="does not match"):
            validate_pattern("invalid", r"^\d{3}-\d{4}$")


# ============================================================================
# RECOVERY AND RESILIENCE TESTS
# ============================================================================


@pytest.mark.asyncio
class TestRecoveryAndResilience:
    """Test system recovery and resilience."""

    async def test_automatic_retry_success(self) -> None:
        """Test automatic retry succeeds on second attempt."""
        attempt_count = 0

        async def flaky_operation() -> str:
            nonlocal attempt_count
            await asyncio.sleep(0)  # ensure async
            attempt_count += 1
            if attempt_count < COUNT_TWO:
                msg = "Temporary failure"
                raise RuntimeError(msg)
            return "success"

        # Retry logic
        for attempt in range(3):
            try:
                result = await flaky_operation()
                assert result == "success"
                break
            except RuntimeError:
                if attempt == COUNT_TWO:
                    raise

    async def test_circuit_breaker_pattern(self) -> None:
        """Test circuit breaker pattern."""

        class CircuitBreaker:
            def __init__(self, failure_threshold: Any = 3) -> None:
                self.failure_count = 0
                self.failure_threshold = failure_threshold
                self.is_open = False

            async def call(self, func: Any, *args: Any) -> None:
                if self.is_open:
                    msg = "Circuit breaker is open"
                    raise RuntimeError(msg)

                try:
                    result = await func(*args)
                    self.failure_count = 0
                    return result
                except RuntimeError:
                    self.failure_count += 1
                    if self.failure_count >= self.failure_threshold:
                        self.is_open = True
                    raise

        breaker = CircuitBreaker(failure_threshold=2)

        async def failing_op() -> Never:
            await asyncio.sleep(0)  # ensure async
            msg = "Operation failed"
            raise RuntimeError(msg)

        # First failure
        with pytest.raises(RuntimeError, match="Operation failed"):
            await breaker.call(failing_op)

        # Second failure
        with pytest.raises(RuntimeError, match="Operation failed"):
            await breaker.call(failing_op)

        # Circuit should be open now
        with pytest.raises(RuntimeError, match="Circuit breaker is open"):
            await breaker.call(failing_op)

    async def test_fallback_mechanism(self) -> None:
        """Test fallback mechanism on error."""

        async def primary_operation() -> Never:
            await asyncio.sleep(0)
            msg = "Primary failed"
            raise RuntimeError(msg)

        async def fallback_operation() -> str:
            await asyncio.sleep(0)
            return "fallback_result"

        try:
            result = await primary_operation()
        except Exception:
            result = await fallback_operation()

        assert result == "fallback_result"

    async def test_graceful_degradation(self) -> None:
        """Test graceful degradation."""

        class Service:
            def __init__(self) -> None:
                self.cache_enabled = True

            async def get_data(self, key: Any, use_cache: Any = True) -> None:
                try:
                    if use_cache and self.cache_enabled:
                        return await self._get_from_cache(key)
                    return await self._get_from_source(key)
                except Exception:
                    # Degrade gracefully
                    if use_cache:
                        return await self._get_from_source(key)
                    raise

            async def _get_from_cache(self, _key: Any) -> Never:
                msg = "Cache failed"
                raise Exception(msg)

            async def _get_from_source(self, _key: Any) -> None:
                return {"data": "value"}

        service = Service()
        result = await service.get_data("key")
        assert result == {"data": "value"}


if __name__ == "__main__":
    pytest.main([__file__, "-v"])
