/**
 * Provider Router Types (RFC-0054)
 */

import type { ProviderState } from "../../types/src/runtime-types.ts";
import type { Capability } from "../../capability-registry/src/types.ts";

// Re-export Latency from here for convenience
export type Latency = "fast" | "medium" | "slow";

// ─── Routing Types ─────────────────────────────────────────────────────

export type RoutingStrategy =
	| "cheapest"
	| "fastest"
	| "best_quality"
	| "balanced"
	| "quota_aware";

export interface RoutingPolicy {
	defaultStrategy: RoutingStrategy;
	costWeight: number; // 0-100
	qualityWeight: number; // 0-100
	latencyWeight: number; // 0-100
	quotaWeight: number; // 0-100
	fallbackProviders: string[];
	taskTypeOverrides: Record<string, RoutingStrategy>;
	providerPreferences: Record<string, number>;
}

export interface QuotaState {
	exhausted: boolean;
	remainingPct: number;
}

export interface RoutingContext {
	task: {
		id: string;
		title: string;
		description: string;
		type: string;
	};
	requirement?: {
		id: string;
		description: string;
	};
	providerStates: Record<string, ProviderState>;
	quotaStates: Record<string, QuotaState>;
	costBudget?: {
		remaining: number;
	};
}

export interface RoutingOptions {
	preferCheapest?: boolean;
	preferFastest?: boolean;
	preferHighestQuality?: boolean;
	maxCostPerTask?: number;
	requiredCapabilities?: Capability[];
	preferProviders?: string[];
	avoidProviders?: string[];
}

export interface ProviderCandidate {
	providerId: string;
	modelId: string;
	capabilities: Capability[];
	estimatedCost?: number;
	estimatedLatency: Latency;
	qualityScore?: number;
	remainingQuotaPct: number;
}

export interface RoutingDecision {
	providerId: string;
	modelId: string;
	reason: string;
	estimatedCost?: number;
	estimatedLatency?: Latency;
	confidence: number;
}

// ─── Router Interface ──────────────────────────────────────────────────

export interface ProviderRouter {
	selectProvider(
		task: RoutingContext["task"],
		context: RoutingContext,
		options?: RoutingOptions,
	): Promise<RoutingDecision>;

	selectProviders(
		task: RoutingContext["task"],
		context: RoutingContext,
		count: number,
	): Promise<RoutingDecision[]>;

	getRoutingPolicy(): RoutingPolicy;
	setRoutingPolicy(policy: RoutingPolicy): void;
}

// ─── Event Types ─────────────────────────────────────────────────────

export type ProviderRouterEvent =
	| {
			type: "router.provider_selected";
			taskId: string;
			providerId: string;
			reason: string;
	  }
	| { type: "router.no_candidates"; taskId: string; reason: string }
	| {
			type: "router.policy_updated";
			oldPolicy: RoutingPolicy;
			newPolicy: RoutingPolicy;
	  }
	| {
			type: "router.fallback_triggered";
			taskId: string;
			originalProvider: string;
			fallbackProvider: string;
	  };

// ─── Latency Ranking ─────────────────────────────────────────────────

export const LATENCY_RANK: Record<Latency, number> = {
	fast: 1,
	medium: 2,
	slow: 3,
};