import sys
from app.database.session import SessionLocal
from slowapi import Limiter
from slowapi.util import get_remote_address
from app.core.config import settings

# ---------------------------------------------------------------------------
# Local dummy implementations that replace the private engine classes.
# They provide the same interface as the originals but perform no real work.
# ---------------------------------------------------------------------------
class RiskEngine:
    def __init__(self, *args, **kwargs):
        pass
    def calculate_risk(self, *args, **kwargs):
        return (0.38, "mock", {"conjugate_mean": 0.38})
    def update_outcome(self, *args, **kwargs):
        pass

class DecisionEngine:
    def __init__(self, *args, **kwargs):
        pass
    def select_optimal_action(self, *args, **kwargs):
        class Result:
            best_action = type('Action', (), {'value': 'NO_ACTION'})()
            expected_utility = 0.0
            alternatives = []
            explanation = "mock"
            raw_data = {}
        return Result()
    def compute_risk(self, *args, **kwargs):
        return 0.0

class LyapunovStabilityController:
    def __init__(self, *args, **kwargs):
        pass

class CausalExplainer:
    def __init__(self, *args, **kwargs):
        pass

class RAGGraphMemory:
    def __init__(self, *args, **kwargs):
        pass
    def has_historical_data(self):
        return False
    def record_outcome(self, *args, **kwargs):
        pass

class ReliabilityEvent:
    def __init__(self, component, latency_p99, error_rate, service_mesh="default"):
        self.component = component
        self.latency_p99 = latency_p99
        self.error_rate = error_rate
        self.service_mesh = service_mesh

class HealingAction:
    NO_ACTION = "NO_ACTION"
    RESTART_CONTAINER = "RESTART_CONTAINER"
    SCALE_OUT = "SCALE_OUT"
    ROLLBACK = "ROLLBACK"
    CIRCUIT_BREAKER = "CIRCUIT_BREAKER"
    TRAFFIC_SHIFT = "TRAFFIC_SHIFT"
    ALERT_TEAM = "ALERT_TEAM"
# ---------------------------------------------------------------------------


def get_db():
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()


limiter = Limiter(key_func=get_remote_address, default_limits=[settings.RATE_LIMIT])


# Singletons (now using local dummies)
_risk_engine = None
_decision_engine = None
_stability_controller = None
_causal_explainer = None
_rag_graph = None


def _seed_rag_graph(rag):
    # Mock seed – no real data
    print("RAG seed skipped (sandbox mode)", file=sys.stderr)


def get_rag_graph():
    global _rag_graph
    if _rag_graph is None:
        _rag_graph = RAGGraphMemory()
        _seed_rag_graph(_rag_graph)
    return _rag_graph


def get_decision_engine():
    global _decision_engine
    if _decision_engine is None:
        rag = get_rag_graph()
        _decision_engine = DecisionEngine(rag_graph=rag)
    return _decision_engine


def get_risk_engine():
    global _risk_engine
    if _risk_engine is None:
        _risk_engine = RiskEngine()
    return _risk_engine


def get_stability_controller():
    global _stability_controller
    if _stability_controller is None:
        _stability_controller = LyapunovStabilityController()
    return _stability_controller


def get_causal_explainer():
    global _causal_explainer
    if _causal_explainer is None:
        _causal_explainer = CausalExplainer()
    return _causal_explainer