core/microservices.py

"""
Domain-Driven Microservices Architecture for Zenith
Implements clean architecture with bounded contexts
"""

import asyncio
import logging
import os
from abc import ABC, abstractmethod
from dataclasses import dataclass
from enum import Enum
from typing import Any

from fastapi import FastAPI, HTTPException

# Configure logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

# Development flag - set via environment variable
IS_DEVELOPMENT = os.getenv("ENVIRONMENT", "development").lower() == "development"


class BoundedContext(Enum):
    """Domain bounded contexts"""

    CASE_MANAGEMENT = "case_management"
    FRAUD_DETECTION = "fraud_detection"
    EVIDENCE_PROCESSING = "evidence_processing"
    USER_MANAGEMENT = "user_management"
    REPORTING_ANALYTICS = "reporting_analytics"
    INTEGRATION_HUB = "integration_hub"


@dataclass
class DomainEvent:
    """Base domain event"""

    event_id: str
    event_type: str
    aggregate_id: str
    event_data: dict[str, Any]
    timestamp: float
    version: int = 1


class DomainEventBus:
    """In-memory domain event bus for inter-service communication"""

    def __init__(self):
        self._handlers: dict[str, list[callable]] = {}
        self._published_events: list[DomainEvent] = []

    def subscribe(self, event_type: str, handler: callable):
        """Subscribe to domain events"""
        if event_type not in self._handlers:
            self._handlers[event_type] = []
        self._handlers[event_type].append(handler)

    async def publish(self, event: DomainEvent):
        """Publish domain event to all subscribers"""
        logger.info(f"Publishing event: {event.event_type}")
        self._published_events.append(event)

        if event.event_type in self._handlers:
            tasks = []
            for handler in self._handlers[event.event_type]:
                tasks.append(handler(event))
            await asyncio.gather(*tasks, return_exceptions=True)

    def get_published_events(self, event_type: str | None = None) -> list[DomainEvent]:
        """Get published events, optionally filtered by type"""
        if event_type:
            return [e for e in self._published_events if e.event_type == event_type]
        return self._published_events.copy()


# Global event bus instance
event_bus = DomainEventBus()


class Microservice(ABC):
    """Base microservice class"""

    def __init__(self, name: str, bounded_context: BoundedContext):
        self.name = name
        self.bounded_context = bounded_context
        self.app = FastAPI(title=f"{name} Service")
        self.dependencies = {}
        self._setup_routes()
        self._setup_event_handlers()

    @abstractmethod
    def _setup_routes(self):
        """Setup FastAPI routes"""

    @abstractmethod
    def _setup_event_handlers(self):
        """Setup domain event handlers"""

    def add_dependency(self, name: str, dependency: Any):
        """Add dependency injection"""
        self.dependencies[name] = dependency

    def get_dependency(self, name: str) -> Any:
        """Get dependency"""
        return self.dependencies.get(name)


class CaseManagementService(Microservice):
    """Case Management Bounded Context"""

    def __init__(self):
        super().__init__("Case Management", BoundedContext.CASE_MANAGEMENT)
        self.cases = {}  # In-memory storage (would be database in production)

    def _setup_routes(self):
        @self.app.post("/cases")
        async def create_case(case_data: dict[str, Any]):
            case_id = f"case_{len(self.cases) + 1}"
            self.cases[case_id] = case_data

            # Publish domain event
            event = DomainEvent(
                event_id=f"evt_{case_id}",
                event_type="case.created",
                aggregate_id=case_id,
                event_data=case_data,
                timestamp=asyncio.get_event_loop().time(),
            )
            await event_bus.publish(event)

            return {"case_id": case_id, "status": "created"}

        @self.app.get("/cases/{case_id}")
        async def get_case(case_id: str):
            if case_id not in self.cases:
                raise HTTPException(status_code=404, detail="Case not found")
            return self.cases[case_id]

        @self.app.put("/cases/{case_id}/status")
        async def update_case_status(case_id: str, status: str):
            if case_id not in self.cases:
                raise HTTPException(status_code=404, detail="Case not found")

            old_status = self.cases[case_id].get("status")
            self.cases[case_id]["status"] = status

            # Publish status change event
            event = DomainEvent(
                event_id=f"evt_{case_id}_status",
                event_type="case.status_changed",
                aggregate_id=case_id,
                event_data={"old_status": old_status, "new_status": status},
                timestamp=asyncio.get_event_loop().time(),
            )
            await event_bus.publish(event)

            return {"status": "updated"}

    def _setup_event_handlers(self):
        # Handle fraud detection events
        async def handle_fraud_detected(event: DomainEvent):
            case_id = event.aggregate_id
            logger.info(f"Case {case_id} marked as potential fraud")

        event_bus.subscribe("fraud.detected", handle_fraud_detected)


class FraudDetectionService(Microservice):
    """Fraud Detection Bounded Context"""

    def __init__(self):
        super().__init__("Fraud Detection", BoundedContext.FRAUD_DETECTION)
        self.fraud_rules = {}
        self.active_scans = set()

    def _setup_routes(self):
        @self.app.post("/scan/transaction")
        async def scan_transaction(transaction: dict[str, Any]):
            transaction_id = transaction.get("id", "unknown")

            # Simulate fraud detection logic
            is_fraudulent = self._detect_fraud(transaction)

            result = {
                "transaction_id": transaction_id,
                "is_fraudulent": is_fraudulent,
                "risk_score": 0.8 if is_fraudulent else 0.2,
                "flags": ["high_amount", "unusual_location"] if is_fraudulent else [],
            }

            if is_fraudulent:
                # Publish fraud detected event
                event = DomainEvent(
                    event_id=f"fraud_{transaction_id}",
                    event_type="fraud.detected",
                    aggregate_id=transaction.get("case_id", "unknown"),
                    event_data=result,
                    timestamp=asyncio.get_event_loop().time(),
                )
                await event_bus.publish(event)

            return result

        @self.app.post("/rules")
        async def create_fraud_rule(rule: dict[str, Any]):
            rule_id = f"rule_{len(self.fraud_rules) + 1}"
            self.fraud_rules[rule_id] = rule
            return {"rule_id": rule_id, "status": "created"}

        @self.app.get("/rules")
        async def get_fraud_rules():
            return list(self.fraud_rules.values())

    def _detect_fraud(self, transaction: dict[str, Any]) -> bool:
        """Simple fraud detection logic"""
        amount = transaction.get("amount", 0)
        location = transaction.get("location", "")

        # Simple rules
        if amount > 10000:
            return True
        return location in ["high_risk_country_1", "high_risk_country_2"]

    def _setup_event_handlers(self):
        # Handle case status changes
        async def handle_case_status_changed(event: DomainEvent):
            case_id = event.aggregate_id
            new_status = event.event_data.get("new_status")

            if new_status == "INVESTIGATING":
                logger.info(f"Initiating fraud scan for case {case_id}")
                self.active_scans.add(case_id)

        event_bus.subscribe("case.status_changed", handle_case_status_changed)


class EvidenceProcessingService(Microservice):
    """Evidence Processing Bounded Context"""

    def __init__(self):
        super().__init__("Evidence Processing", BoundedContext.EVIDENCE_PROCESSING)
        self.processing_queue = asyncio.Queue()
        self.processed_evidence = {}

    def _setup_routes(self):
        @self.app.post("/evidence/process")
        async def process_evidence(evidence_data: dict[str, Any]):
            evidence_id = evidence_data.get(
                "id", f"evidence_{len(self.processed_evidence) + 1}"
            )

            # Add to processing queue
            await self.processing_queue.put(evidence_data)

            # Start background processing
            task = asyncio.create_task(
                self._process_evidence(evidence_id, evidence_data)
            )
            self._background_tasks.append(task)

            return {"evidence_id": evidence_id, "status": "processing"}

        @self.app.get("/evidence/{evidence_id}")
        async def get_evidence(evidence_id: str):
            if evidence_id not in self.processed_evidence:
                raise HTTPException(status_code=404, detail="Evidence not found")
            return self.processed_evidence[evidence_id]

    async def _process_evidence(self, evidence_id: str, evidence_data: dict[str, Any]):
        """Background evidence processing"""
        try:
            logger.info(f"Processing evidence {evidence_id}")

            # Simulate processing time only in development
            if IS_DEVELOPMENT:
                await asyncio.sleep(2)

            # Mock OCR and analysis
            processed_data = {
                **evidence_data,
                "ocr_text": "Extracted text from evidence document...",
                "sentiment_score": 0.7,
                "entities_extracted": ["John Doe", "ABC Bank", "$50,000"],
                "processing_status": "completed",
                "processed_at": asyncio.get_event_loop().time(),
            }

            self.processed_evidence[evidence_id] = processed_data

            # Publish processing completed event
            event = DomainEvent(
                event_id=f"evidence_processed_{evidence_id}",
                event_type="evidence.processed",
                aggregate_id=evidence_id,
                event_data=processed_data,
                timestamp=asyncio.get_event_loop().time(),
            )
            await event_bus.publish(event)

            logger.info(f"Evidence {evidence_id} processing completed")

        except Exception as e:
            logger.error(f"Evidence processing failed for {evidence_id}: {e}")

    def _setup_event_handlers(self):
        # Handle case creation events
        async def handle_case_created(event: DomainEvent):
            case_id = event.aggregate_id
            logger.info(f"Evidence processing service notified of new case {case_id}")

        event_bus.subscribe("case.created", handle_case_created)


class UserManagementService(Microservice):
    """User Management Bounded Context"""

    def __init__(self):
        super().__init__("User Management", BoundedContext.USER_MANAGEMENT)
        self.users = {}
        self.roles = {
            "admin": ["read", "write", "delete", "manage_users"],
            "investigator": ["read", "write", "investigate"],
            "analyst": ["read", "analyze"],
            "viewer": ["read"],
        }

    def _setup_routes(self):
        @self.app.post("/users")
        async def create_user(user_data: dict[str, Any]):
            user_id = user_data.get("email", f"user_{len(self.users) + 1}")
            user_data["permissions"] = self.roles.get(
                user_data.get("role", "viewer"), []
            )
            self.users[user_id] = user_data

            # Publish user created event
            event = DomainEvent(
                event_id=f"user_{user_id}",
                event_type="user.created",
                aggregate_id=user_id,
                event_data=user_data,
                timestamp=asyncio.get_event_loop().time(),
            )
            await event_bus.publish(event)

            return {"user_id": user_id, "status": "created"}

        @self.app.get("/users/{user_id}")
        async def get_user(user_id: str):
            if user_id not in self.users:
                raise HTTPException(status_code=404, detail="User not found")
            return self.users[user_id]

        @self.app.get("/users/{user_id}/permissions")
        async def get_user_permissions(user_id: str):
            if user_id not in self.users:
                raise HTTPException(status_code=404, detail="User not found")
            return {"permissions": self.users[user_id].get("permissions", [])}

    def _setup_event_handlers(self):
        # Handle case assignment events
        async def handle_case_assigned(event: DomainEvent):
            user_id = event.event_data.get("assignee_id")
            case_id = event.aggregate_id

            if user_id in self.users:
                logger.info(f"User {user_id} assigned to case {case_id}")

        event_bus.subscribe("case.assigned", handle_case_assigned)


class ReportingAnalyticsService(Microservice):
    """Reporting & Analytics Bounded Context"""

    def __init__(self):
        super().__init__("Reporting & Analytics", BoundedContext.REPORTING_ANALYTICS)
        self.reports = {}
        self.analytics_cache = {}

    def _setup_routes(self):
        @self.app.post("/reports/generate")
        async def generate_report(report_config: dict[str, Any]):
            report_id = f"report_{len(self.reports) + 1}"
            report_type = report_config.get("type", "case_summary")

            # Generate mock report data
            report_data = await self._generate_report_data(report_type, report_config)

            self.reports[report_id] = {
                "id": report_id,
                "type": report_type,
                "data": report_data,
                "generated_at": asyncio.get_event_loop().time(),
                "config": report_config,
            }

            return {"report_id": report_id, "status": "generated", "data": report_data}

        @self.app.get("/analytics/dashboard")
        async def get_dashboard_analytics():
            # Aggregate analytics from all services
            analytics = {
                "total_cases": await self._get_total_cases(),
                "fraud_detected": await self._get_fraud_count(),
                "evidence_processed": await self._get_evidence_count(),
                "active_users": await self._get_active_users(),
                "system_health": "healthy",
            }

            return analytics

    async def _generate_report_data(
        self, report_type: str, config: dict[str, Any]
    ) -> dict[str, Any]:
        """Generate report data based on type"""
        if report_type == "case_summary":
            return {
                "total_cases": 150,
                "open_cases": 45,
                "closed_cases": 105,
                "high_priority": 12,
                "fraud_cases": 28,
            }
        elif report_type == "fraud_trends":
            return {
                "monthly_fraud_count": [5, 8, 12, 15, 9, 11],
                "fraud_amounts": [50000, 75000, 120000, 150000, 90000, 110000],
                "detection_accuracy": 0.94,
            }
        else:
            return {"message": f"Report type {report_type} generated"}

    async def _get_total_cases(self) -> int:
        # Would query case management service
        return 150

    async def _get_fraud_count(self) -> int:
        # Would query fraud detection service
        return 28

    async def _get_evidence_count(self) -> int:
        # Would query evidence processing service
        return 320

    async def _get_active_users(self) -> int:
        # Would query user management service
        return 45

    def _setup_event_handlers(self):
        # Listen to all domain events for analytics
        async def handle_any_event(event: DomainEvent):
            # Update analytics cache
            event_type = event.event_type
            if event_type not in self.analytics_cache:
                self.analytics_cache[event_type] = 0
            self.analytics_cache[event_type] += 1

        # Subscribe to multiple event types
        for event_type in [
            "case.created",
            "fraud.detected",
            "evidence.processed",
            "user.created",
        ]:
            event_bus.subscribe(event_type, handle_any_event)


class IntegrationHubService(Microservice):
    """Integration Hub Bounded Context"""

    def __init__(self):
        super().__init__("Integration Hub", BoundedContext.INTEGRATION_HUB)
        self.integrations = {}
        self.webhooks = {}

    def _setup_routes(self):
        @self.app.post("/integrations")
        async def create_integration(integration_config: dict[str, Any]):
            integration_id = f"integration_{len(self.integrations) + 1}"
            self.integrations[integration_id] = integration_config

            return {"integration_id": integration_id, "status": "created"}

        @self.app.post("/webhooks/{webhook_id}")
        async def handle_webhook(webhook_id: str, payload: dict[str, Any]):
            if webhook_id not in self.webhooks:
                raise HTTPException(status_code=404, detail="Webhook not found")

            webhook_config = self.webhooks[webhook_id]

            # Process webhook based on configuration
            event_type = webhook_config.get("event_type", "external.event")
            event = DomainEvent(
                event_id=f"webhook_{webhook_id}_{asyncio.get_event_loop().time()}",
                event_type=event_type,
                aggregate_id=webhook_id,
                event_data=payload,
                timestamp=asyncio.get_event_loop().time(),
            )

            await event_bus.publish(event)

            return {"status": "processed"}

        @self.app.get("/integrations/status")
        async def get_integration_status():
            # Return status of all integrations
            return {
                integration_id: {
                    "status": "active",
                    "last_sync": asyncio.get_event_loop().time(),
                    "health": "good",
                }
                for integration_id in self.integrations
            }

    def _setup_event_handlers(self):
        # Handle external events
        async def handle_external_event(event: DomainEvent):
            logger.info(f"Processing external event: {event.event_type}")

        event_bus.subscribe("external.event", handle_external_event)


class MicroservicesOrchestrator:
    """Orchestrates all microservices"""

    def __init__(self):
        self.services: dict[BoundedContext, Microservice] = {}
        self.service_ports = {
            BoundedContext.CASE_MANAGEMENT: 8001,
            BoundedContext.FRAUD_DETECTION: 8002,
            BoundedContext.EVIDENCE_PROCESSING: 8003,
            BoundedContext.USER_MANAGEMENT: 8004,
            BoundedContext.REPORTING_ANALYTICS: 8005,
            BoundedContext.INTEGRATION_HUB: 8006,
        }

    def register_service(self, service: Microservice):
        """Register a microservice"""
        self.services[service.bounded_context] = service
        logger.info(f"Registered service: {service.name}")

    def get_service(self, bounded_context: BoundedContext) -> Microservice | None:
        """Get a registered service"""
        return self.services.get(bounded_context)

    async def start_all_services(self):
        """Start all registered microservices"""
        logger.info("Starting all microservices...")

        tasks = []
        for bounded_context, service in self.services.items():
            port = self.service_ports[bounded_context]
            task = asyncio.create_task(self._start_service(service, port))
            tasks.append(task)
            self._service_tasks.append(task)

        await asyncio.gather(*tasks)
        logger.info("All microservices started")

    async def _start_service(self, service: Microservice, port: int):
        """Start a single service on specified port"""
        try:
            import uvicorn

            config = uvicorn.Config(
                service.app, host="0.0.0.0", port=port, log_level="info"
            )
            server = uvicorn.Server(config)
            await server.serve()
        except Exception as e:
            logger.error(f"Failed to start {service.name} on port {port}: {e}")

    async def health_check_all(self) -> dict[str, bool]:
        """Perform health check on all services"""
        health_status = {}

        for service in self.services.values():
            try:
                # Simple health check - would be more sophisticated in production
                health_status[service.name] = True
            except Exception as e:
                logger.error(f"Health check failed for {service.name}: {e}")
                health_status[service.name] = False

        return health_status

    def get_service_discovery_info(self) -> dict[str, dict[str, Any]]:
        """Get service discovery information"""
        discovery_info = {}

        for bounded_context, service in self.services.items():
            port = self.service_ports[bounded_context]
            discovery_info[service.name] = {
                "bounded_context": bounded_context.value,
                "port": port,
                "endpoint": f"http://localhost:{port}",
                "status": "active",
            }

        return discovery_info


# Create and configure microservices
def create_microservices_orchestrator() -> MicroservicesOrchestrator:
    """Create and configure the microservices orchestrator"""

    orchestrator = MicroservicesOrchestrator()

    # Register all microservices
    orchestrator.register_service(CaseManagementService())
    orchestrator.register_service(FraudDetectionService())
    orchestrator.register_service(EvidenceProcessingService())
    orchestrator.register_service(UserManagementService())
    orchestrator.register_service(ReportingAnalyticsService())
    orchestrator.register_service(IntegrationHubService())

    return orchestrator


# Export for use
__all__ = [
    "BoundedContext",
    "CaseManagementService",
    "DomainEvent",
    "DomainEventBus",
    "EvidenceProcessingService",
    "FraudDetectionService",
    "IntegrationHubService",
    "Microservice",
    "MicroservicesOrchestrator",
    "ReportingAnalyticsService",
    "UserManagementService",
    "create_microservices_orchestrator",
    "event_bus",
]