"""
Deep behavioral tests for event processing patterns.
Tests event creation, publishing, subscription,
handling, and replay logic.
"""

from datetime import datetime, timezone, timedelta
import uuid


# --- Event creation patterns ---


class TestEventCreation:
    """Tests for event creation patterns."""

    def _create_event(self, event_type, payload, **metadata):
        """Create an event."""
        return {
            "id": str(uuid.uuid4()),
            "type": event_type,
            "payload": payload,
            "timestamp": datetime.now(timezone.utc),
            "metadata": metadata,
        }

    def test_has_id(self):
        event = self._create_event("user.created", {"user_id": "123"})
        assert "id" in event
        assert len(event["id"]) > 0

    def test_has_type(self):
        event = self._create_event("user.created", {"user_id": "123"})
        assert event["type"] == "user.created"

    def test_has_payload(self):
        event = self._create_event("user.created", {"user_id": "123"})
        assert event["payload"]["user_id"] == "123"

    def test_has_timestamp(self):
        event = self._create_event("user.created", {})
        assert "timestamp" in event

    def test_includes_metadata(self):
        event = self._create_event("user.created", {}, source="api", version=1)
        assert event["metadata"]["source"] == "api"
        assert event["metadata"]["version"] == 1


class TestEventTypeValidation:
    """Tests for event type validation."""

    def _validate_event_type(self, event_type):
        """Validate event type format."""
        if not event_type or not isinstance(event_type, str):
            return False
        parts = event_type.split(".")
        if len(parts) < 2:
            return False
        return all(p.isidentifier() for p in parts)

    def test_valid_two_part_type(self):
        assert self._validate_event_type("user.created") is True

    def test_valid_three_part_type(self):
        assert self._validate_event_type("subscription.card.updated") is True

    def test_invalid_single_part(self):
        assert self._validate_event_type("created") is False

    def test_invalid_empty(self):
        assert self._validate_event_type("") is False


# --- Event publishing patterns ---


class TestEventPublishing:
    """Tests for event publishing patterns."""

    def _publish_event(self, event_bus, event):
        """Publish event to bus."""
        if "events" not in event_bus:
            event_bus["events"] = []
        event_bus["events"].append(event)
        return len(event_bus["events"])

    def _publish_batch(self, event_bus, events):
        """Publish multiple events."""
        if "events" not in event_bus:
            event_bus["events"] = []
        event_bus["events"].extend(events)
        return len(events)

    def test_publish_adds_to_bus(self):
        bus = {}
        event = {"id": "1", "type": "test"}
        self._publish_event(bus, event)
        assert len(bus["events"]) == 1

    def test_publish_returns_count(self):
        bus = {}
        count = self._publish_event(bus, {"id": "1"})
        assert count == 1

    def test_publish_batch(self):
        bus = {}
        events = [{"id": "1"}, {"id": "2"}, {"id": "3"}]
        published = self._publish_batch(bus, events)
        assert published == 3
        assert len(bus["events"]) == 3


# --- Event subscription patterns ---


class TestEventSubscription:
    """Tests for event subscription patterns."""

    def _subscribe(self, subscriptions, event_type, handler_id):
        """Subscribe to an event type."""
        if event_type not in subscriptions:
            subscriptions[event_type] = []
        subscriptions[event_type].append(handler_id)
        return True

    def _unsubscribe(self, subscriptions, event_type, handler_id):
        """Unsubscribe from an event type."""
        if event_type in subscriptions:
            if handler_id in subscriptions[event_type]:
                subscriptions[event_type].remove(handler_id)
                return True
        return False

    def _get_handlers(self, subscriptions, event_type):
        """Get handlers for an event type."""
        return subscriptions.get(event_type, [])

    def test_subscribe_adds_handler(self):
        subs = {}
        self._subscribe(subs, "user.created", "handler1")
        assert "handler1" in subs["user.created"]

    def test_unsubscribe_removes_handler(self):
        subs = {"user.created": ["handler1"]}
        result = self._unsubscribe(subs, "user.created", "handler1")
        assert result is True
        assert "handler1" not in subs["user.created"]

    def test_get_handlers(self):
        subs = {"user.created": ["h1", "h2"]}
        handlers = self._get_handlers(subs, "user.created")
        assert len(handlers) == 2


class TestWildcardSubscription:
    """Tests for wildcard event subscription patterns."""

    def _matches_pattern(self, event_type, pattern):
        """Check if event type matches subscription pattern."""
        if pattern == "*":
            return True
        if pattern.endswith(".*"):
            prefix = pattern[:-2]
            return event_type.startswith(prefix + ".")
        return event_type == pattern

    def _get_matching_handlers(self, subscriptions, event_type):
        """Get all handlers that match event type."""
        handlers = []
        for pattern, pattern_handlers in subscriptions.items():
            if self._matches_pattern(event_type, pattern):
                handlers.extend(pattern_handlers)
        return handlers

    def test_exact_match(self):
        assert self._matches_pattern("user.created", "user.created") is True
        assert self._matches_pattern("user.created", "user.updated") is False

    def test_wildcard_all(self):
        assert self._matches_pattern("user.created", "*") is True
        assert self._matches_pattern("subscription.updated", "*") is True

    def test_prefix_wildcard(self):
        assert self._matches_pattern("user.created", "user.*") is True
        assert self._matches_pattern("user.updated", "user.*") is True
        assert self._matches_pattern("card.created", "user.*") is False

    def test_get_matching_handlers(self):
        subs = {
            "user.created": ["h1"],
            "user.*": ["h2"],
            "*": ["h3"],
        }
        handlers = self._get_matching_handlers(subs, "user.created")
        assert "h1" in handlers
        assert "h2" in handlers
        assert "h3" in handlers


# --- Event handling patterns ---


class TestEventHandling:
    """Tests for event handling patterns."""

    def _handle_event(self, event, handler):
        """Handle an event with a handler."""
        try:
            result = handler(event)
            return {"success": True, "result": result}
        except Exception as e:
            return {"success": False, "error": str(e)}

    def _dispatch_event(self, event, handlers):
        """Dispatch event to multiple handlers."""
        results = []
        for handler in handlers:
            result = self._handle_event(event, handler)
            results.append(result)
        return results

    def test_successful_handling(self):
        event = {"type": "test", "payload": {"value": 42}}

        def handler(e):
            return e["payload"]["value"] * 2

        result = self._handle_event(event, handler)
        assert result["success"] is True
        assert result["result"] == 84

    def test_failed_handling(self):
        event = {"type": "test"}

        def failing_handler(e):
            raise ValueError("Handler failed")

        result = self._handle_event(event, failing_handler)
        assert result["success"] is False
        assert "Handler failed" in result["error"]

    def test_dispatch_to_multiple(self):
        event = {"type": "test", "payload": {"v": 1}}
        handlers = [
            lambda e: e["payload"]["v"],
            lambda e: e["payload"]["v"] * 2,
        ]
        results = self._dispatch_event(event, handlers)
        assert len(results) == 2
        assert results[0]["result"] == 1
        assert results[1]["result"] == 2


# --- Event ordering patterns ---


class TestEventOrdering:
    """Tests for event ordering patterns."""

    def _sort_by_timestamp(self, events):
        """Sort events by timestamp."""
        return sorted(events, key=lambda e: e.get("timestamp", datetime.min))

    def _get_sequence_number(self, event_store, event_type):
        """Get next sequence number for event type."""
        key = f"seq_{event_type}"
        current = event_store.get(key, 0)
        event_store[key] = current + 1
        return current + 1

    def test_sorts_by_timestamp(self):
        now = datetime.now(timezone.utc)
        events = [
            {"id": "2", "timestamp": now + timedelta(seconds=1)},
            {"id": "1", "timestamp": now},
            {"id": "3", "timestamp": now + timedelta(seconds=2)},
        ]
        sorted_events = self._sort_by_timestamp(events)
        assert sorted_events[0]["id"] == "1"
        assert sorted_events[2]["id"] == "3"

    def test_sequence_numbers_increment(self):
        store = {}
        seq1 = self._get_sequence_number(store, "user")
        seq2 = self._get_sequence_number(store, "user")
        seq3 = self._get_sequence_number(store, "user")
        assert seq1 == 1
        assert seq2 == 2
        assert seq3 == 3


# --- Event filtering patterns ---


class TestEventFiltering:
    """Tests for event filtering patterns."""

    def _filter_by_type(self, events, event_type):
        """Filter events by type."""
        return [e for e in events if e.get("type") == event_type]

    def _filter_by_time_range(self, events, start=None, end=None):
        """Filter events by time range."""
        filtered = []
        for event in events:
            timestamp = event.get("timestamp")
            if timestamp is None:
                continue
            if start and timestamp < start:
                continue
            if end and timestamp > end:
                continue
            filtered.append(event)
        return filtered

    def _filter_by_payload(self, events, **criteria):
        """Filter events by payload criteria."""
        filtered = []
        for event in events:
            payload = event.get("payload", {})
            matches = all(payload.get(k) == v for k, v in criteria.items())
            if matches:
                filtered.append(event)
        return filtered

    def test_filter_by_type(self):
        events = [
            {"type": "user.created"},
            {"type": "card.created"},
            {"type": "user.created"},
        ]
        filtered = self._filter_by_type(events, "user.created")
        assert len(filtered) == 2

    def test_filter_by_time_range(self):
        now = datetime.now(timezone.utc)
        events = [
            {"timestamp": now - timedelta(hours=2)},
            {"timestamp": now - timedelta(hours=1)},
            {"timestamp": now},
        ]
        start = now - timedelta(hours=1, minutes=30)
        filtered = self._filter_by_time_range(events, start=start)
        assert len(filtered) == 2

    def test_filter_by_payload(self):
        events = [
            {"payload": {"user_id": "1", "status": "active"}},
            {"payload": {"user_id": "2", "status": "inactive"}},
            {"payload": {"user_id": "3", "status": "active"}},
        ]
        filtered = self._filter_by_payload(events, status="active")
        assert len(filtered) == 2


# --- Event replay patterns ---


class TestEventReplay:
    """Tests for event replay patterns."""

    def _replay_events(self, events, handler, from_sequence=0):
        """Replay events from a sequence number."""
        replayed = 0
        for event in events:
            if event.get("sequence", 0) > from_sequence:
                handler(event)
                replayed += 1
        return replayed

    def _create_snapshot(self, state, last_event_id):
        """Create a snapshot for replay optimization."""
        return {
            "state": state.copy(),
            "last_event_id": last_event_id,
            "created_at": datetime.now(timezone.utc),
        }

    def test_replay_from_sequence(self):
        events = [
            {"sequence": 1, "type": "test"},
            {"sequence": 2, "type": "test"},
            {"sequence": 3, "type": "test"},
        ]
        handled = []
        replayed = self._replay_events(events, handled.append, from_sequence=1)
        assert replayed == 2

    def test_snapshot_creation(self):
        state = {"count": 10, "last_update": "2025-01-01"}
        snapshot = self._create_snapshot(state, "event-100")
        assert snapshot["state"]["count"] == 10
        assert snapshot["last_event_id"] == "event-100"


# --- Event deduplication patterns ---


class TestEventDeduplication:
    """Tests for event deduplication patterns."""

    def _is_duplicate(self, event, seen_ids):
        """Check if event is a duplicate."""
        event_id = event.get("id")
        if event_id in seen_ids:
            return True
        seen_ids.add(event_id)
        return False

    def _deduplicate(self, events):
        """Remove duplicate events."""
        seen = set()
        unique = []
        for event in events:
            if event.get("id") not in seen:
                seen.add(event.get("id"))
                unique.append(event)
        return unique

    def test_detects_duplicate(self):
        seen = {"event-1", "event-2"}
        event = {"id": "event-1"}
        assert self._is_duplicate(event, seen) is True

    def test_new_event_not_duplicate(self):
        seen = {"event-1"}
        event = {"id": "event-2"}
        assert self._is_duplicate(event, seen) is False
        assert "event-2" in seen

    def test_deduplicate_list(self):
        events = [
            {"id": "1", "value": "a"},
            {"id": "2", "value": "b"},
            {"id": "1", "value": "a"},  # duplicate
        ]
        unique = self._deduplicate(events)
        assert len(unique) == 2


# --- Event versioning patterns ---


class TestEventVersioning:
    """Tests for event versioning patterns."""

    def _create_versioned_event(self, event_type, payload, version=1):
        """Create a versioned event."""
        return {
            "type": event_type,
            "version": version,
            "payload": payload,
        }

    def _is_compatible(self, event_version, handler_version):
        """Check if event version is compatible with handler."""
        return event_version <= handler_version

    def _upgrade_event(self, event, from_version, to_version, upgrades):
        """Upgrade event through version chain."""
        current = event.copy()
        for v in range(from_version, to_version):
            if v in upgrades:
                current = upgrades[v](current)
        current["version"] = to_version
        return current

    def test_create_versioned_event(self):
        event = self._create_versioned_event(
            "user.created", {"name": "test"}, version=2
        )
        assert event["version"] == 2

    def test_compatibility_check(self):
        assert self._is_compatible(1, 2) is True  # Can handle older
        assert self._is_compatible(3, 2) is False  # Can't handle newer

    def test_upgrade_event(self):
        event = {"version": 1, "payload": {"name": "test"}}
        upgrades = {
            1: lambda e: {**e, "payload": {**e["payload"], "status": "active"}},
        }
        upgraded = self._upgrade_event(event, 1, 2, upgrades)
        assert upgraded["version"] == 2
        assert upgraded["payload"]["status"] == "active"


# --- Dead letter queue patterns ---


class TestDeadLetterQueue:
    """Tests for dead letter queue patterns."""

    def _move_to_dlq(self, dlq, event, error):
        """Move failed event to dead letter queue."""
        dlq_entry = {
            "original_event": event,
            "error": str(error),
            "failed_at": datetime.now(timezone.utc),
            "retry_count": event.get("_retry_count", 0) + 1,
        }
        dlq.append(dlq_entry)
        return len(dlq)

    def _should_move_to_dlq(self, event, max_retries=3):
        """Check if event should go to DLQ after max retries."""
        return event.get("_retry_count", 0) >= max_retries

    def test_move_to_dlq(self):
        dlq = []
        event = {"id": "1", "type": "test"}
        self._move_to_dlq(dlq, event, "Processing failed")
        assert len(dlq) == 1
        assert dlq[0]["original_event"] == event

    def test_should_move_after_retries(self):
        event = {"_retry_count": 3}
        assert self._should_move_to_dlq(event) is True

    def test_should_not_move_before_max(self):
        event = {"_retry_count": 1}
        assert self._should_move_to_dlq(event) is False


# --- Event correlation patterns ---


class TestEventCorrelation:
    """Tests for event correlation patterns."""

    def _correlate_events(self, events, correlation_id):
        """Find all events with same correlation ID."""
        return [e for e in events if e.get("correlation_id") == correlation_id]

    def _build_event_chain(self, events, correlation_id):
        """Build ordered chain of correlated events."""
        correlated = self._correlate_events(events, correlation_id)
        return sorted(
            correlated, key=lambda e: e.get("timestamp", datetime.min)
        )

    def test_correlate_events(self):
        events = [
            {"id": "1", "correlation_id": "req-1"},
            {"id": "2", "correlation_id": "req-2"},
            {"id": "3", "correlation_id": "req-1"},
        ]
        correlated = self._correlate_events(events, "req-1")
        assert len(correlated) == 2

    def test_build_event_chain(self):
        now = datetime.now(timezone.utc)
        events = [
            {
                "id": "3",
                "correlation_id": "req-1",
                "timestamp": now + timedelta(seconds=2),
            },
            {"id": "1", "correlation_id": "req-1", "timestamp": now},
            {
                "id": "2",
                "correlation_id": "req-1",
                "timestamp": now + timedelta(seconds=1),
            },
        ]
        chain = self._build_event_chain(events, "req-1")
        assert chain[0]["id"] == "1"
        assert chain[2]["id"] == "3"


# --- Event aggregation patterns ---


class TestEventAggregation:
    """Tests for event aggregation patterns."""

    def _aggregate_by_type(self, events):
        """Aggregate events by type."""
        aggregated = {}
        for event in events:
            event_type = event.get("type", "unknown")
            if event_type not in aggregated:
                aggregated[event_type] = []
            aggregated[event_type].append(event)
        return aggregated

    def _count_by_type(self, events):
        """Count events by type."""
        counts = {}
        for event in events:
            event_type = event.get("type", "unknown")
            counts[event_type] = counts.get(event_type, 0) + 1
        return counts

    def test_aggregate_by_type(self):
        events = [
            {"type": "user.created"},
            {"type": "card.created"},
            {"type": "user.created"},
        ]
        aggregated = self._aggregate_by_type(events)
        assert len(aggregated["user.created"]) == 2
        assert len(aggregated["card.created"]) == 1

    def test_count_by_type(self):
        events = [
            {"type": "a"},
            {"type": "b"},
            {"type": "a"},
            {"type": "a"},
        ]
        counts = self._count_by_type(events)
        assert counts["a"] == 3
        assert counts["b"] == 1
