"""Outcome recording with idempotency, no dummy fallbacks, and timezone-aware timestamps."""

import datetime
import logging
from typing import Optional, Dict, Any

from sqlalchemy.orm import Session
from sqlalchemy.exc import IntegrityError

from agentic_reliability_framework.core.governance.risk_engine import RiskEngine
from agentic_reliability_framework.core.governance.intents import (
    InfrastructureIntent,
    ProvisionResourceIntent,
    GrantAccessIntent,
    DeployConfigurationIntent,
)
from app.database.models_intents import IntentDB, OutcomeDB, BetaStateDB

logger = logging.getLogger(__name__)


# ---------------------------------------------------------------------------
# NEW: small helper to persist the conjugate posterior state
# ---------------------------------------------------------------------------
def _persist_beta_state(db: Session, risk_engine: RiskEngine) -> None:
    """
    Write the current Beta posterior parameters to the beta_state table.
    This is called after every outcome update so that online learning
    survives restarts.
    """
    try:
        state = risk_engine.beta_store.get_state()
        for cat, (alpha, beta) in state.items():
            # Upsert: if the category already exists, update it
            db.merge(BetaStateDB(category=cat.value, alpha=alpha, beta=beta))
        db.commit()
        logger.debug("Persisted Beta posterior parameters to database.")
    except Exception as e:
        db.rollback()
        logger.error("Failed to persist beta state: %s", e)


class OutcomeConflictError(Exception):
    """Raised when an outcome already exists for the same intent with a different result."""
    pass


def reconstruct_oss_intent_from_json(
        oss_json: Dict[str, Any]) -> InfrastructureIntent:
    """Reconstruct OSS intent from stored JSON. Raises ValueError on failure."""
    intent_type = oss_json.get("intent_type")
    if intent_type == "provision_resource":
        return ProvisionResourceIntent(**oss_json)
    elif intent_type == "grant_access":
        return GrantAccessIntent(**oss_json)
    elif intent_type == "deploy_config":
        return DeployConfigurationIntent(**oss_json)
    else:
        raise ValueError(
            f"Cannot reconstruct intent from JSON: missing or unknown intent_type {intent_type}")


def record_outcome(
    db: Session,
    deterministic_id: str,
    success: bool,
    recorded_by: Optional[str],
    notes: Optional[str],
    risk_engine: RiskEngine,
    idempotency_key: Optional[str] = None,
) -> OutcomeDB:
    """
    Record an outcome for a previously evaluated intent.

    Idempotent: calling twice with the same (deterministic_id, success) returns the same record.
    If the outcome already exists with a different success value, raises OutcomeConflictError.

    No dummy intents are created. If the OSS intent cannot be reconstructed, the risk engine
    is NOT updated – we log an error and still record the outcome.

    Args:
        db: SQLAlchemy session.
        deterministic_id: Unique identifier of the original intent.
        success: Whether the action succeeded (True) or failed (False).
        recorded_by: Optional user or system identifier.
        notes: Optional human-readable notes.
        risk_engine: ARF risk engine instance (may be updated).
        idempotency_key: Optional caller-provided idempotency token.

    Returns:
        The recorded OutcomeDB object.

    Raises:
        ValueError: If intent not found or reconstruction fails fatally.
        OutcomeConflictError: If a conflicting outcome already exists.
    """
    # 1. Fetch the original intent record
    intent = db.query(IntentDB).filter(
        IntentDB.deterministic_id == deterministic_id).one_or_none()
    if not intent:
        raise ValueError(f"Intent not found: {deterministic_id}")

    # 2. Idempotency / conflict check with database-level uniqueness
    existing_outcome = db.query(OutcomeDB).filter(
        OutcomeDB.intent_id == intent.id).one_or_none()
    if existing_outcome:
        if existing_outcome.success == success:
            return existing_outcome
        db.rollback()
        raise OutcomeConflictError(
            f"Outcome already recorded for intent {deterministic_id} with different result "
            f"(existing={existing_outcome.success}, new={success})"
        )

    # 3. Create outcome record
    outcome = OutcomeDB(
        intent_id=intent.id,
        success=bool(success),
        recorded_by=recorded_by,
        notes=notes,
        recorded_at=datetime.datetime.now(datetime.timezone.utc),
        idempotency_key=idempotency_key,
    )
    db.add(outcome)

    # 4. Attempt to commit; handle duplicate key errors for idempotency
    try:
        db.commit()
        db.refresh(outcome)
    except IntegrityError as e:
        db.rollback()
        if "idempotency_key" in str(e) and idempotency_key:
            existing = db.query(OutcomeDB).filter(
                OutcomeDB.idempotency_key == idempotency_key).first()
            if existing:
                logger.info(
                    "Idempotent request for key %s, returning existing outcome",
                    idempotency_key)
                return existing
        raise

    # 5. Update RiskEngine ONLY if we can reconstruct a valid OSS intent
    oss_intent = None
    if intent.oss_payload:
        try:
            oss_intent = reconstruct_oss_intent_from_json(intent.oss_payload)
        except Exception as e:
            logger.error(
                "Failed to reconstruct OSS intent for %s: %s. RiskEngine will NOT be updated.",
                deterministic_id,
                e,
                exc_info=True)
    else:
        logger.warning(
            "No oss_payload stored for intent %s – cannot update RiskEngine.",
            deterministic_id
        )

    if oss_intent is not None:
        try:
            risk_engine.update_outcome(oss_intent, success)

            # ----------------------------------------------------------------
            # PERSISTENCE: after updating the conjugate posterior, write it
            # ----------------------------------------------------------------
            _persist_beta_state(db, risk_engine)

        except Exception as e:
            logger.exception(
                "Failed to update RiskEngine after recording outcome for intent %s: %s",
                deterministic_id,
                e)
    else:
        logger.info(
            "Skipped RiskEngine update for intent %s (no valid OSS intent)",
            deterministic_id
        )

    return outcome