import { Injectable } from '@angular/core'; import { HttpClient } from '@angular/common/http'; import { Observable, ReplaySubject, throwError, of } from 'rxjs'; import { tap, shareReplay, switchMap, share } from 'rxjs/operators';

@Injectable({ providedIn: 'root' }) export class ApiCallService {

// This is your "semaphore". // null = "not sent" // Observable = "in progress" or "completed" private userDetailsCache$: Observable | null = null;

// --- TODO: Define your userDetails endpoint URL --- private readonly USER_DETAILS_URL = '/api/v1/userDetails';

constructor(private httpClient: HttpClient) { }

/**

• This private function is the "semaphore" logic.
• It ensures the userDetails call runs only once. */ private getOrFetchUserDetails(): Observable { // "Not sent": Create the request, make it "in progress" if (!this.userDetailsCache$) { this.userDetailsCache$ = this.httpClient.get(this.USER_DETAILS_URL).pipe( tap(userInfo => { // --- TODO: Store your token here --- // Example: localStorage.setItem('auth_token', userInfo.token); }), // shareReplay(1) is the magic: // 1. It multicasts the result to all subscribers. // 2. It caches the last (1) emission. // 3. Any new subscriber gets the cached value instantly. shareReplay(1) ); }

// "In progress" or "Completed": Return the observable
return this.userDetailsCache$;

}

/**

• Your modified function. */ public apicall(params: any): Observable {

// --- TODO: Your existing logic to parse params ---
const { method, url, body, options } = this.buildRequestFromParams(params);

// --- Prevent recursive loop ---
// If the call *is* for userDetails, just return the semaphore.
if (url === this.USER_DETAILS_URL) {
  return this.getOrFetchUserDetails().pipe(share());
}

// --- All other calls ---
// 1. Get the semaphore. This will either:
//    a) Trigger the userDetails call (if "not sent")
//    b) Wait for the in-progress call
//    c) Get the cached result instantly
// 
// 2. Use switchMap to wait ("hold") until the semaphore emits.
//
// 3. Once it emits, proceed ("unlocked") to the actual HTTP request.
return this.getOrFetchUserDetails().pipe(
  switchMap(userInfo => {
    // Token is now guaranteed to be stored.
    // Make the real request.
    return this.createHttpRequest(method, url, body, options);
  }),
  share() // Keep your original share()
);

}

// --- Helper to create the actual request --- private createHttpRequest(method: string, url: string, body?: any, options?: any): Observable { switch (method.toLowerCase()) { case 'get': return this.httpClient.get(url, options); case 'post': return this.httpClient.post(url, body, options); case 'put': return this.httpClient.put(url, body, options); case 'delete': return this.httpClient.delete(url, options); default: return throwError(() => new Error('Invalid HTTP method')); } }

// --- TODO: Replace with your actual helper function --- private buildRequestFromParams(params: any): { method: string, url: string, body?: any, options?: any } { // Example placeholder return { method: params.method || 'get', url: params.url, body: params.body, options: params.options }; } }