"""
IOM Lager 8 — Risk Alert System
Alert-system för risktrösklar med notifieringar.
"""

from __future__ import annotations

import asyncio
import json
import time
from dataclasses import dataclass, field, asdict
from datetime import datetime, timezone
from enum import Enum
from typing import Callable, Dict, List, Optional, Set, Any
import threading

from risk_model import RiskResult, RiskDimension


class AlertSeverity(str, Enum):
    LOW = "low"
    MEDIUM = "medium"
    HIGH = "high"
    CRITICAL = "critical"


class AlertStatus(str, Enum):
    ACTIVE = "active"
    ACKNOWLEDGED = "acknowledged"
    RESOLVED = "resolved"
    SILENCED = "silenced"


# Tröskelvärden för alert-nivåer
RISK_THRESHOLDS = {
    AlertSeverity.CRITICAL: 9.0,
    AlertSeverity.HIGH: 7.0,
    AlertSeverity.MEDIUM: 5.0,
    AlertSeverity.LOW: 3.0,
}


@dataclass
class AlertRule:
    """Regel för när en alert ska triggas."""
    rule_id: str
    name: str
    description: str = ""
    # Trösklar
    min_total_risk: Optional[float] = None
    min_risk_level: Optional[int] = None
    dimension_thresholds: Dict[str, float] = field(default_factory=dict)
    # Filter
    domains: Optional[List[str]] = None
    object_type_codes: Optional[List[str]] = None
    goids: Optional[List[str]] = None
    # Åtgärd
    severity: AlertSeverity = AlertSeverity.MEDIUM
    auto_acknowledge_after_minutes: Optional[int] = None
    cooldown_minutes: int = 60
    enabled: bool = True


@dataclass
class Alert:
    """En enskild alert."""
    alert_id: str
    rule_id: str
    goid: str
    severity: AlertSeverity
    status: AlertStatus
    message: str
    risk_result: RiskResult
    created_at: str
    acknowledged_at: Optional[str] = None
    acknowledged_by: Optional[str] = None
    resolved_at: Optional[str] = None
    resolved_by: Optional[str] = None
    resolution_note: Optional[str] = None
    auto_resolve_after: Optional[str] = None

    def to_dict(self) -> Dict[str, Any]:
        d = asdict(self)
        d["risk_result"] = {
            "goid": self.risk_result.goid,
            "total_risk": self.risk_result.total_risk,
            "risk_level": self.risk_result.risk_level,
            "dimension_scores": self.risk_result.dimension_scores,
            "alert_triggered": self.risk_result.alert_triggered,
            "alert_level": self.risk_result.alert_level,
        }
        return d


NotifierCallback = Callable[[Alert], None]


class RiskAlertManager:
    """Central hanterare för risk-alerts."""

    def __init__(self):
        self._rules: Dict[str, AlertRule] = {}
        self._alerts: Dict[str, Alert] = {}
        self._goid_alerts: Dict[str, Set[str]] = {}  # goid → alert_ids
        self._notifiers: List[NotifierCallback] = []
        self._lock = threading.RLock()
        self._cooldowns: Dict[str, float] = {}  # goid+rule_id → timestamp

    # ─── Regelhantering ──────────────────────────────────────────────────────

    def add_rule(self, rule: AlertRule) -> None:
        with self._lock:
            self._rules[rule.rule_id] = rule

    def remove_rule(self, rule_id: str) -> bool:
        with self._lock:
            return self._rules.pop(rule_id, None) is not None

    def get_rule(self, rule_id: str) -> Optional[AlertRule]:
        with self._lock:
            return self._rules.get(rule_id)

    def list_rules(self) -> List[AlertRule]:
        with self._lock:
            return list(self._rules.values())

    def enable_rule(self, rule_id: str) -> bool:
        with self._lock:
            if rule := self._rules.get(rule_id):
                rule.enabled = True
                return True
            return False

    def disable_rule(self, rule_id: str) -> bool:
        with self._lock:
            if rule := self._rules.get(rule_id):
                rule.enabled = False
                return True
            return False

    # ─── Notifieringar ───────────────────────────────────────────────────────

    def register_notifier(self, callback: NotifierCallback) -> None:
        with self._lock:
            self._notifiers.append(callback)

    def unregister_notifier(self, callback: NotifierCallback) -> None:
        with self._lock:
            if callback in self._notifiers:
                self._notifiers.remove(callback)

    def _notify(self, alert: Alert) -> None:
        for notifier in list(self._notifiers):
            try:
                notifier(alert)
            except Exception:
                pass  # Isolera fel i notifierare

    # ─── Alert-hantering ─────────────────────────────────────────────────────

    def evaluate(self, risk_result: RiskResult) -> List[Alert]:
        """Utvärdera ett riskresultat mot alla regler och skapa alerts."""
        triggered: List[Alert] = []
        with self._lock:
            for rule in self._rules.values():
                if not rule.enabled:
                    continue
                if not self._rule_matches(rule, risk_result):
                    continue
                cooldown_key = f"{risk_result.goid}:{rule.rule_id}"
                now = time.time()
                last_triggered = self._cooldowns.get(cooldown_key, 0)
                cooldown_seconds = rule.cooldown_minutes * 60
                if now - last_triggered < cooldown_seconds:
                    continue
                self._cooldowns[cooldown_key] = now

                alert = self._create_alert(rule, risk_result)
                self._alerts[alert.alert_id] = alert
                self._goid_alerts.setdefault(risk_result.goid, set()).add(alert.alert_id)
                triggered.append(alert)
                self._notify(alert)
        return triggered

    def _rule_matches(self, rule: AlertRule, result: RiskResult) -> bool:
        # Total risk-tröskel
        if rule.min_total_risk is not None and result.total_risk < rule.min_total_risk:
            return False
        # Risknivå-tröskel
        if rule.min_risk_level is not None and result.risk_level < rule.min_risk_level:
            return False
        # Dimensions-trösklar
        for dim, threshold in rule.dimension_thresholds.items():
            if result.dimension_scores.get(dim, 0) < threshold:
                return False
        # Domän-filter
        if rule.domains is not None:
            domain = result.goid.split("-")[0] if result.goid else None
            if domain not in rule.domains:
                return False
        # GOID-filter
        if rule.goids is not None and result.goid not in rule.goids:
            return False
        # Objekttyp-filter (prefix-match)
        if rule.object_type_codes is not None:
            matched = False
            for code in rule.object_type_codes:
                # Förenklad: antar att GOID börjar med typkoden
                if result.goid.startswith(code):
                    matched = True
                    break
            if not matched:
                return False
        return True

    def _create_alert(self, rule: AlertRule, result: RiskResult) -> Alert:
        now = datetime.now(timezone.utc).isoformat()
        alert_id = f"ALERT-{result.goid}-{rule.rule_id}-{int(time.time())}"
        message = self._build_alert_message(rule, result)
        auto_resolve = None
        if rule.auto_acknowledge_after_minutes:
            auto_resolve_dt = datetime.now(timezone.utc)
            # Sätt auto-resolve-tid
            from datetime import timedelta
            auto_resolve = (auto_resolve_dt + timedelta(minutes=rule.auto_acknowledge_after_minutes)).isoformat()

        return Alert(
            alert_id=alert_id,
            rule_id=rule.rule_id,
            goid=result.goid,
            severity=rule.severity,
            status=AlertStatus.ACTIVE,
            message=message,
            risk_result=result,
            created_at=now,
            auto_resolve_after=auto_resolve,
        )

    def _build_alert_message(self, rule: AlertRule, result: RiskResult) -> str:
        parts = [
            f"Risk alert för {result.goid}",
            f"Regel: {rule.name}",
            f"Total risk: {result.total_risk}/10 (nivå {result.risk_level})",
        ]
        if result.alert_level:
            parts.append(f"Alert-nivå: {result.alert_level}")
        # Lista höga dimensioner
        high_dims = [
            d for d, v in result.dimension_scores.items() if v >= 7.0
        ]
        if high_dims:
            parts.append(f"Högrisk-dimensioner: {', '.join(high_dims)}")
        return " | ".join(parts)

    def acknowledge_alert(
        self, alert_id: str, user: str, note: Optional[str] = None
    ) -> Optional[Alert]:
        with self._lock:
            if alert := self._alerts.get(alert_id):
                if alert.status == AlertStatus.ACTIVE:
                    alert.status = AlertStatus.ACKNOWLEDGED
                    alert.acknowledged_at = datetime.now(timezone.utc).isoformat()
                    alert.acknowledged_by = user
                    if note:
                        alert.resolution_note = note
                    return alert
            return None

    def resolve_alert(
        self, alert_id: str, user: str, note: Optional[str] = None
    ) -> Optional[Alert]:
        with self._lock:
            if alert := self._alerts.get(alert_id):
                alert.status = AlertStatus.RESOLVED
                alert.resolved_at = datetime.now(timezone.utc).isoformat()
                alert.resolved_by = user
                if note:
                    alert.resolution_note = note
                return alert
            return None

    def silence_alert(self, alert_id: str, duration_minutes: int = 1440) -> Optional[Alert]:
        with self._lock:
            if alert := self._alerts.get(alert_id):
                alert.status = AlertStatus.SILENCED
                return alert
            return None

    def get_alert(self, alert_id: str) -> Optional[Alert]:
        with self._lock:
            return self._alerts.get(alert_id)

    def list_alerts(
        self,
        goid: Optional[str] = None,
        status: Optional[AlertStatus] = None,
        severity: Optional[AlertSeverity] = None,
    ) -> List[Alert]:
        with self._lock:
            alerts = list(self._alerts.values())
        if goid:
            alerts = [a for a in alerts if a.goid == goid]
        if status:
            alerts = [a for a in alerts if a.status == status]
        if severity:
            alerts = [a for a in alerts if a.severity == severity]
        return sorted(alerts, key=lambda a: a.created_at, reverse=True)

    def get_active_alerts_for_goid(self, goid: str) -> List[Alert]:
        with self._lock:
            alert_ids = self._goid_alerts.get(goid, set())
            alerts = [self._alerts[aid] for aid in alert_ids if aid in self._alerts]
        return [a for a in alerts if a.status == AlertStatus.ACTIVE]

    def get_alert_summary(self) -> Dict[str, Any]:
        with self._lock:
            total = len(self._alerts)
            by_status: Dict[str, int] = {}
            by_severity: Dict[str, int] = {}
            for alert in self._alerts.values():
                by_status[alert.status.value] = by_status.get(alert.status.value, 0) + 1
                by_severity[alert.severity.value] = by_severity.get(alert.severity.value, 0) + 1
        return {
            "total_alerts": total,
            "by_status": by_status,
            "by_severity": by_severity,
            "active_rules": len([r for r in self._rules.values() if r.enabled]),
        }

    def clear_old_alerts(self, max_age_hours: int = 168) -> int:
        """Rensa lösta alerts äldre än max_age_hours."""
        cutoff = time.time() - (max_age_hours * 3600)
        removed = 0
        with self._lock:
            to_remove = [
                aid for aid, alert in self._alerts.items()
                if alert.status in (AlertStatus.RESOLVED, AlertStatus.SILENCED)
                and self._parse_ts(alert.created_at) < cutoff
            ]
            for aid in to_remove:
                alert = self._alerts.pop(aid)
                self._goid_alerts.get(alert.goid, set()).discard(aid)
                removed += 1
        return removed

    @staticmethod
    def _parse_ts(ts: str) -> float:
        try:
            dt = datetime.fromisoformat(ts.replace("Z", "+00:00"))
            return dt.timestamp()
        except Exception:
            return 0.0


# ─── Färdiga notifierare ─────────────────────────────────────────────────────

class ConsoleNotifier:
    """Skriver alerts till stdout."""

    def __call__(self, alert: Alert) -> None:
        print(f"\n🚨 [{alert.severity.upper()}] {alert.message}")
        print(f"   Alert ID: {alert.alert_id}")
        print(f"   Skapad: {alert.created_at}\n")


class WebhookNotifier:
    """Skickar alerts via HTTP POST."""

    def __init__(self, webhook_url: str, headers: Optional[Dict[str, str]] = None):
        self.webhook_url = webhook_url
        self.headers = headers or {"Content-Type": "application/json"}

    def __call__(self, alert: Alert) -> None:
        import urllib.request
        payload = json.dumps(alert.to_dict(), default=str).encode("utf-8")
        req = urllib.request.Request(
            self.webhook_url,
            data=payload,
            headers=self.headers,
            method="POST",
        )
        try:
            with urllib.request.urlopen(req, timeout=10) as resp:
                pass
        except Exception as exc:
            print(f"WebhookNotifier failed: {exc}")


# ─── Global instans ──────────────────────────────────────────────────────────

_alert_manager: Optional[RiskAlertManager] = None


def get_alert_manager() -> RiskAlertManager:
    global _alert_manager
    if _alert_manager is None:
        _alert_manager = RiskAlertManager()
    return _alert_manager


def reset_alert_manager() -> None:
    global _alert_manager
    _alert_manager = None