import { Service } from '@n8n/di';

import { paginatedRequest } from '@/utils/strapi-utils';

import type { McpRegistryServer } from './mcp-registry.types';

export type McpRegistryServerMetadata = Pick<McpRegistryServer, 'slug' | 'version' | 'updatedAt'>;

const MCP_SERVERS_DEV_URL = 'http://127.0.0.1:1337/api/mcp-servers';
const MCP_SERVERS_STAGING_URL = 'https://api-staging.n8n.io/api/mcp-servers';
const MCP_SERVERS_PRODUCTION_URL = 'https://api.n8n.io/api/mcp-servers';

/** Strapi's qs parser has an arrayLimit of 100 */
const STRAPI_ARRAY_LIMIT = 100;

@Service()
export class McpRegistryApiClient {
	async fetchAllServers(): Promise<McpRegistryServer[]> {
		return await paginatedRequest<McpRegistryServer>(
			this.getUrl(),
			{
				pagination: { page: 1, pageSize: 25 },
			},
			{
				throwOnError: true,
			},
		);
	}

	async fetchServersMetadata(): Promise<McpRegistryServerMetadata[]> {
		return await paginatedRequest<McpRegistryServerMetadata>(
			this.getUrl(),
			{
				fields: ['slug', 'version', 'updatedAt'],
				pagination: { page: 1, pageSize: 500 },
			},
			{
				throwOnError: true,
			},
		);
	}

	async fetchServersBySlugs(slugs: string[]): Promise<McpRegistryServer[]> {
		const data: McpRegistryServer[] = [];
		for (let i = 0; i < slugs.length; i += STRAPI_ARRAY_LIMIT) {
			const batch = slugs.slice(i, i + STRAPI_ARRAY_LIMIT);
			const batchData = await paginatedRequest<McpRegistryServer>(
				this.getUrl(),
				{
					filters: {
						slug: {
							$in: batch,
						},
					},
					pagination: { page: 1, pageSize: 25 },
				},
				{
					throwOnError: true,
				},
			);
			data.push(...batchData);
		}

		return data;
	}

	private getUrl(): string {
		switch (process.env.ENVIRONMENT) {
			case 'dev':
				return process.env.N8N_MCP_SERVERS_DEV_URL || MCP_SERVERS_DEV_URL;
			case 'staging':
				return MCP_SERVERS_STAGING_URL;
			default:
				return MCP_SERVERS_PRODUCTION_URL;
		}
	}
}