import { randomUUID } from 'node:crypto';
import type { NextRequest } from 'next/server';
import type { IService } from 'soma-core';
import { AiApiRuntime } from '../../../domain/ai-api/AiApiRuntime';
import { aiErrorResponse, aiSuccessResponse } from '../../../domain/ai-shared/AiResponse';
import { readBodyParams, runService } from '../../common/ServiceRuntime';

const REQUEST_ID_HEADER = 'X-Request-Id';
const REQUEST_ID_PATTERN = /^[A-Za-z0-9][A-Za-z0-9._:-]{0,127}$/;

export default class InvokeService implements IService {
  async post(req: NextRequest): Promise<Response> {
    const requestId = resolveRequestId(req.headers.get('x-request-id'));
    return runService(async () => {
      try {
        const body = await readBodyParams(req);
        const result = await AiApiRuntime.getInstance().invoke(
          body.func as string,
          body.input as Record<string, string>,
          req.signal,
        );
        return withRequestId(aiSuccessResponse({
          func: body.func,
          output: result.output,
          meta: {
            ...result.meta,
            requestId,
          },
        }), requestId);
      } catch (error) {
        return withRequestId(aiErrorResponse(error), requestId);
      }
    });
  }
}

export function resolveRequestId(candidate: string | null): string {
  return candidate !== null && REQUEST_ID_PATTERN.test(candidate) ? candidate : randomUUID();
}

function withRequestId(response: Response, requestId: string): Response {
  response.headers.set(REQUEST_ID_HEADER, requestId);
  return response;
}