/**
 * Provider Registry — map providerKind to EmbeddingProvider instances.
 *
 * Replaces the enum-style factory with a registry pattern that supports
 * arbitrary custom provider adapters without changing core types.
 */

import type { EmbeddingProvider } from './provider.js';
import { NoopEmbeddingProvider } from './provider.js';
import { OpenAIEmbeddingProvider } from './openai.provider.js';
import { LocalEmbeddingProvider } from './local.provider.js';
import type { EmbeddingProfile } from '../db/schema.js';

export type ProviderFactory = (config: Record<string, unknown>) => EmbeddingProvider;

const PROVIDER_REGISTRY: Record<string, ProviderFactory> = {
	'local-transformers': () => new LocalEmbeddingProvider(),
	'openai-compatible': (config) =>
		new OpenAIEmbeddingProvider({
			baseUrl: config.baseUrl as string,
			apiKey: config.apiKey as string,
			model: config.model as string,
			dimensions: config.dimensions as number | undefined,
			maxBatchSize: config.maxBatchSize as number | undefined
		})
};

/**
 * Create an EmbeddingProvider from a persisted EmbeddingProfile.
 *
 * Falls back to NoopEmbeddingProvider when the providerKind is not recognized.
 */
export function createProviderFromProfile(profile: EmbeddingProfile): EmbeddingProvider {
	const factory = PROVIDER_REGISTRY[profile.providerKind];
	if (!factory) return new NoopEmbeddingProvider();
	const config = (profile.config as Record<string, unknown>) ?? {};
	return factory(config);
}

/**
 * Return metadata for the default local profile.
 *
 * Used by migration seeds and runtime defaults.
 */
export function getDefaultLocalProfile(): Pick<
	EmbeddingProfile,
	'id' | 'providerKind' | 'model' | 'dimensions'
> {
	return {
		id: 'local-default',
		providerKind: 'local-transformers',
		model: 'Xenova/all-MiniLM-L6-v2',
		dimensions: 384
	};
}

/**
 * Return all registered providerKind values.
 *
 * Useful for settings UI validation and provider discovery.
 */
export function getRegisteredProviderKinds(): string[] {
	return Object.keys(PROVIDER_REGISTRY);
}