import { environment } from '../environments/environment';
import { demoTabAtLoad } from '../services/authStorage';
import { noteDemoRefusal } from '../services/demoTab';

declare const AKASHIC_CLIENT_VERSION: string | undefined;

/** What this client is, as the API is told: the contract it speaks and the build it came from. */
export const CLIENT_MANIFEST = {
    apiContract: 'v1',
    clientVersion: typeof AKASHIC_CLIENT_VERSION === 'string' && AKASHIC_CLIENT_VERSION ? AKASHIC_CLIENT_VERSION : 'unknown',
} as const;

export const CLIENT_VERSION_HEADER = 'X-Akashic-Client-Version';

const API_BASES = [
    'apiUrl', 'fhirFoundationApi', 'fhirBaseApi', 'fhirIdentityApi', 'fhirClinicalApi', 'orgAuthorizationApi',
    'fhirGuardianshipApi', 'liveFhirBaseApi', 'liveFhirFoundationApi', 'sandboxFhirFoundationApi',
] as const;

const originOf = (url: string): string | undefined => {
    try {
        return new URL(url, typeof window === 'undefined' ? undefined : window.location.href).origin;
    } catch {
        return undefined;
    }
};

/** Only our own REST API gets the header; S3, Stripe and Cognito would answer an unknown header with a CORS refusal. */
export const isAkashicApiUrl = (url: string): boolean => {
    const origin = originOf(url);
    if (!origin) return false;
    const env = environment as unknown as Record<string, string | undefined>;
    return API_BASES.some((key) => env[key] && originOf(env[key] as string) === origin);
};

const withHeader = (headers: HeadersInit | undefined): HeadersInit => {
    if (headers instanceof Headers) {
        const next = new Headers(headers);
        next.set(CLIENT_VERSION_HEADER, CLIENT_MANIFEST.clientVersion);
        return next;
    }
    if (Array.isArray(headers)) return [...headers, [CLIENT_VERSION_HEADER, CLIENT_MANIFEST.clientVersion]];
    return { ...(headers ?? {}), [CLIENT_VERSION_HEADER]: CLIENT_MANIFEST.clientVersion };
};

/** The request options with the client version added when the URL is one of our API hosts. */
export const withClientVersion = <T extends RequestInit>(url: string | URL, init: T = {} as T): T =>
    isAkashicApiUrl(String(url)) ? { ...init, headers: withHeader(init.headers) } : init;

/** `fetch` for callers that cannot go through HttpService; it adds the client version on our API hosts. */
export const akashicFetch = async (url: string | URL, init?: RequestInit): Promise<Response> => {
    const response = await fetch(url, withClientVersion(url, init ?? {}));
    // A demo tab hears a refusal that ends its visit here too, not only through HttpService.
    if (demoTabAtLoad) void noteDemoRefusal(response.clone());
    return response;
};