import { isSFCCError } from './type-guards';

export type ExtractVariables<T> = T extends { variables: object } ? T['variables'] : never;

export async function salesforceFetch<T>({
  method,
  cache = 'force-cache',
  headers,
  tags,
  variables,
  apiEndpoint
}: {
  method: 'POST' | 'GET';
  apiEndpoint: string;
  cache?: RequestCache;
  headers?: HeadersInit;
  tags?: string[];
  variables?: ExtractVariables<T>;
}): Promise<{ status: number; body: T } | never> {
  try {
    const fetchOptions: RequestInit = {
      method,
      headers: {
        'Content-Type': 'application/json',
        ...headers
      },
      cache,
      ...(tags && { next: { tags } })
    };

    if (method === 'POST' && variables) {
      fetchOptions.body = JSON.stringify({ variables });
    }

    const res = await fetch(apiEndpoint, fetchOptions);

    const body = await res.json();

    if (body.errors) {
      throw body.errors[0];
    }

    return {
      status: res.status,
      body
    };
  } catch (e) {
    if (isSFCCError(e)) {
      throw {
        version: e._v || 'unknown',
        fault: e?.fault || {},
        apiEndpoint
      };
    }

    throw {
      error: e
    };
  }
}

export const validateEnvironmentVariables = () => {
  const requiredEnvironmentVariables = [
    'SITE_NAME',
    'SFCC_CLIENT_ID',
    'SFCC_ORGANIZATIONID',
    'SFCC_SECRET',
    'SFCC_SHORTCODE',
    'SFCC_SITEID',
    'SFCC_SANDBOX_DOMAIN',
    'SFCC_OPENCOMMERCE_SHOP_API_ENDPOINT',
    'SFCC_REVALIDATION_SECRET'
  ];
  const missingEnvironmentVariables = [] as string[];

  requiredEnvironmentVariables.forEach((envVar) => {
    if (!process.env[envVar]) {
      missingEnvironmentVariables.push(envVar);
    }
  });

  if (missingEnvironmentVariables.length) {
    throw new Error(
      `The following environment variables are missing. Your site will not work without them. Read more: https://vercel.com/docs/integrations/salesforce-commerce-cloud#configure-environment-variables\n\n${missingEnvironmentVariables.join(
        '\n'
      )}\n`
    );
  }
};