# -*- coding: utf-8 -*-
"""
Gewichtete Load-Balancing-Strategie.

Verteilt Anfragen basierend auf konfigurierbaren Gewichten.
"""

import random
from dataclasses import dataclass, field
from typing import Any, TYPE_CHECKING

from trixy_core.satellite.loadbalancing.strategy import (
    LoadBalancingStrategy,
    SelectionResult,
)

if TYPE_CHECKING:
    from trixy_core.satellite.satellite import Satellite


@dataclass
class WeightConfig:
    """
    Gewichtskonfiguration für einen Satellite.

    Attributes:
        weight: Basis-Gewicht (höher = mehr Anfragen)
        health_weight: Faktor basierend auf Gesundheit (0.0-1.0)
        capacity_weight: Faktor basierend auf verfügbarer Kapazität
        custom_factors: Zusätzliche benutzerdefinierte Faktoren
    """
    weight: float = 1.0
    health_weight: float = 1.0
    capacity_weight: float = 1.0
    custom_factors: dict[str, float] = field(default_factory=dict)

    @property
    def effective_weight(self) -> float:
        """Berechnet das effektive Gewicht."""
        base = self.weight * self.health_weight * self.capacity_weight

        for factor in self.custom_factors.values():
            base *= factor

        return max(0.0, base)


class WeightedStrategy(LoadBalancingStrategy):
    """
    Gewichtete Zufallsauswahl.

    Wählt Satellites zufällig basierend auf ihren Gewichten.
    Satellites mit höherem Gewicht werden häufiger gewählt.

    Example:
        strategy = WeightedStrategy()

        # Gewichte setzen
        strategy.set_weight("satellite_1", WeightConfig(weight=3.0))
        strategy.set_weight("satellite_2", WeightConfig(weight=1.0))
        strategy.set_weight("satellite_3", WeightConfig(weight=2.0))

        # Auswahl (satellite_1 wird ~50% gewählt, satellite_3 ~33%, satellite_2 ~17%)
        result = strategy.select(satellites)
    """

    def __init__(self, default_weight: float = 1.0) -> None:
        """
        Initialisiert die gewichtete Strategie.

        Args:
            default_weight: Standard-Gewicht für neue Satellites
        """
        self._default_weight = default_weight
        self._weights: dict[str, WeightConfig] = {}

    @property
    def name(self) -> str:
        """Name der Strategie."""
        return "weighted"

    def set_weight(self, satellite_id: str, config: WeightConfig | float) -> None:
        """
        Setzt das Gewicht für einen Satellite.

        Args:
            satellite_id: Satellite-ID
            config: WeightConfig oder einfaches Gewicht
        """
        if isinstance(config, (int, float)):
            config = WeightConfig(weight=float(config))
        self._weights[satellite_id] = config

    def get_weight(self, satellite_id: str) -> WeightConfig:
        """
        Gibt die Gewichtskonfiguration zurück.

        Args:
            satellite_id: Satellite-ID

        Returns:
            WeightConfig
        """
        return self._weights.get(
            satellite_id,
            WeightConfig(weight=self._default_weight)
        )

    def update_health_weight(self, satellite_id: str, health: float) -> None:
        """
        Aktualisiert das Gesundheitsgewicht.

        Args:
            satellite_id: Satellite-ID
            health: Gesundheitswert (0.0-1.0)
        """
        config = self.get_weight(satellite_id)
        config.health_weight = max(0.0, min(1.0, health))
        self._weights[satellite_id] = config

    def update_capacity_weight(self, satellite_id: str, capacity: float) -> None:
        """
        Aktualisiert das Kapazitätsgewicht.

        Args:
            satellite_id: Satellite-ID
            capacity: Kapazitätswert (0.0-1.0)
        """
        config = self.get_weight(satellite_id)
        config.capacity_weight = max(0.0, min(1.0, capacity))
        self._weights[satellite_id] = config

    def select(
        self,
        satellites: list["Satellite"],
        context: dict[str, Any] | None = None,
    ) -> SelectionResult | None:
        """
        Wählt einen Satellite basierend auf Gewichten.

        Args:
            satellites: Liste verfügbarer Satellites
            context: Optionaler Kontext

        Returns:
            SelectionResult oder None
        """
        if not satellites:
            return None

        # Gewichte berechnen
        weights = []
        for satellite in satellites:
            config = self.get_weight(satellite.id)
            weights.append(config.effective_weight)

        total_weight = sum(weights)

        if total_weight <= 0:
            # Fallback: Gleichverteilung
            selected = random.choice(satellites)
            return SelectionResult(
                satellite=selected,
                reason="Fallback (all weights zero)",
                score=1.0 / len(satellites),
            )

        # Gewichtete Zufallsauswahl
        r = random.uniform(0, total_weight)
        cumulative = 0.0

        for satellite, weight in zip(satellites, weights):
            cumulative += weight
            if r <= cumulative:
                return SelectionResult(
                    satellite=satellite,
                    reason=f"Weighted selection (weight={weight:.2f})",
                    score=weight / total_weight,
                    metadata={
                        "weight": weight,
                        "total_weight": total_weight,
                        "probability": weight / total_weight,
                    }
                )

        # Sollte nicht passieren, Fallback
        return SelectionResult(
            satellite=satellites[-1],
            reason="Fallback (rounding)",
            score=weights[-1] / total_weight if total_weight > 0 else 0,
        )

    def reset(self) -> None:
        """Setzt die Gewichte auf Default zurück."""
        self._weights.clear()

    def get_all_weights(self) -> dict[str, WeightConfig]:
        """Gibt alle Gewichte zurück."""
        return self._weights.copy()


class AdaptiveWeightedStrategy(WeightedStrategy):
    """
    Adaptiv gewichtete Strategie.

    Passt Gewichte automatisch basierend auf Erfolg/Misserfolg an.
    Satellites mit höherer Erfolgsrate erhalten mehr Gewicht.

    Example:
        strategy = AdaptiveWeightedStrategy(
            success_boost=1.1,  # +10% bei Erfolg
            failure_penalty=0.9  # -10% bei Misserfolg
        )

        balancer = LoadBalancer(strategy)
        result = balancer.select(satellites)

        try:
            await result.satellite.speak("Test")
            balancer.end_request(result.satellite, success=True)
        except:
            balancer.end_request(result.satellite, success=False)
    """

    def __init__(
        self,
        default_weight: float = 1.0,
        success_boost: float = 1.05,
        failure_penalty: float = 0.95,
        min_weight: float = 0.1,
        max_weight: float = 10.0,
    ) -> None:
        """
        Initialisiert die adaptive Strategie.

        Args:
            default_weight: Start-Gewicht
            success_boost: Faktor bei Erfolg (>1.0)
            failure_penalty: Faktor bei Misserfolg (<1.0)
            min_weight: Minimales Gewicht
            max_weight: Maximales Gewicht
        """
        super().__init__(default_weight)
        self._success_boost = success_boost
        self._failure_penalty = failure_penalty
        self._min_weight = min_weight
        self._max_weight = max_weight

    @property
    def name(self) -> str:
        """Name der Strategie."""
        return "adaptive_weighted"

    def on_request_end(self, satellite: "Satellite", success: bool = True) -> None:
        """
        Passt das Gewicht basierend auf Erfolg an.

        Args:
            satellite: Der Satellite
            success: Ob erfolgreich
        """
        config = self.get_weight(satellite.id)

        if success:
            new_weight = config.weight * self._success_boost
        else:
            new_weight = config.weight * self._failure_penalty

        # Grenzen einhalten
        new_weight = max(self._min_weight, min(self._max_weight, new_weight))

        config.weight = new_weight
        self._weights[satellite.id] = config


class ResourceBasedStrategy(LoadBalancingStrategy):
    """
    Ressourcenbasierte Auswahl.

    Wählt Satellites basierend auf verfügbaren Ressourcen
    (CPU, Speicher, Netzwerk-Bandbreite etc.).

    Example:
        strategy = ResourceBasedStrategy()

        # Ressourcen aktualisieren (z.B. aus Heartbeat)
        strategy.update_resources("satellite_1", {
            "cpu_available": 0.8,
            "memory_available": 0.6,
            "bandwidth_available": 0.9
        })

        result = strategy.select(satellites)
    """

    def __init__(
        self,
        resource_weights: dict[str, float] | None = None,
    ) -> None:
        """
        Initialisiert die ressourcenbasierte Strategie.

        Args:
            resource_weights: Gewichtung der Ressourcen
        """
        self._resource_weights = resource_weights or {
            "cpu_available": 0.4,
            "memory_available": 0.3,
            "bandwidth_available": 0.3,
        }
        self._resources: dict[str, dict[str, float]] = {}

    @property
    def name(self) -> str:
        """Name der Strategie."""
        return "resource_based"

    def update_resources(self, satellite_id: str, resources: dict[str, float]) -> None:
        """
        Aktualisiert die Ressourcen-Information.

        Args:
            satellite_id: Satellite-ID
            resources: Dict mit Ressourcen (Werte 0.0-1.0)
        """
        self._resources[satellite_id] = resources

    def get_resources(self, satellite_id: str) -> dict[str, float]:
        """Gibt die Ressourcen eines Satellites zurück."""
        return self._resources.get(satellite_id, {})

    def _calculate_score(self, satellite_id: str) -> float:
        """Berechnet den Ressourcen-Score (höher = mehr Ressourcen)."""
        resources = self.get_resources(satellite_id)

        if not resources:
            return 0.5  # Default

        score = 0.0
        total_weight = 0.0

        for resource, weight in self._resource_weights.items():
            if resource in resources:
                score += resources[resource] * weight
                total_weight += weight

        if total_weight > 0:
            return score / total_weight

        return 0.5

    def select(
        self,
        satellites: list["Satellite"],
        context: dict[str, Any] | None = None,
    ) -> SelectionResult | None:
        """
        Wählt den Satellite mit den meisten verfügbaren Ressourcen.

        Args:
            satellites: Liste verfügbarer Satellites
            context: Optionaler Kontext

        Returns:
            SelectionResult oder None
        """
        if not satellites:
            return None

        # Sortiere nach Score (absteigend)
        sorted_satellites = sorted(
            satellites,
            key=lambda s: (-self._calculate_score(s.id), s.id)
        )

        selected = sorted_satellites[0]
        score = self._calculate_score(selected.id)

        return SelectionResult(
            satellite=selected,
            reason=f"Resource-based (score={score:.3f})",
            score=score,
            metadata={
                "resources": self.get_resources(selected.id),
                "calculated_score": score,
            }
        )

    def reset(self) -> None:
        """Setzt die Ressourcen-Daten zurück."""
        self._resources.clear()