/**
 * Provider mirror metadata and model-registry helpers.
 *
 * Both pi-credential-vault and pi-multicodex need to mirror existing
 * provider configurations before installing extension-owned behavior.
 * This module provides a single copy of that logic.
 */
import {
	getApiProvider,
	getModels,
	getProviders,
	type KnownProvider,
} from "@mariozechner/pi-ai";

/**
 * Model definition shape shared by provider mirrors.
 *
 * Captures the subset of a pi-ai Model that extensions need when
 * re-registering a provider via pi.registerProvider().
 */
export interface MirroredModelDef {
	readonly id: string;
	readonly name: string;
	readonly reasoning: boolean;
	readonly input: ReadonlyArray<"text" | "image">;
	readonly cost: {
		readonly input: number;
		readonly output: number;
		readonly cacheRead: number;
		readonly cacheWrite: number;
	};
	readonly contextWindow: number;
	readonly maxTokens: number;
}

/**
 * A snapshot of an existing provider's configuration.
 *
 * Contains everything an extension needs to re-register the provider
 * with modified behavior while preserving the original models and base URL.
 */
export interface MirroredProvider {
	readonly providerId: string;
	readonly baseUrl: string;
	readonly api: string;
	readonly models: ReadonlyArray<MirroredModelDef>;
	readonly hasStreamSimple: boolean;
}

/**
 * Mirror an existing provider's configuration from pi-ai's registry.
 *
 * Returns undefined if the provider has no registered models.
 */
export function mirrorProvider(
	providerId: KnownProvider,
): MirroredProvider | undefined {
	const models = getModels(providerId);
	if (models.length === 0) {
		return undefined;
	}

	const first = models[0];
	if (!first) {
		return undefined;
	}

	const baseProvider = getApiProvider(first.api);
	const baseUrl = first.baseUrl ?? "";

	return {
		providerId,
		baseUrl,
		api: first.api,
		models: models.map((m) => ({
			id: m.id,
			name: m.name,
			reasoning: m.reasoning,
			input: m.input,
			cost: m.cost,
			contextWindow: m.contextWindow,
			maxTokens: m.maxTokens,
		})),
		hasStreamSimple: Boolean(baseProvider),
	};
}

/**
 * List all provider IDs that have at least one registered model.
 *
 * Uses pi-ai's getProviders() — no hardcoded list needed.
 */
export function listProviderIdsWithModels(): KnownProvider[] {
	return getProviders().filter((id) => getModels(id).length > 0);
}