flare-ui/src/app/services/locale-manager.service.ts

// locale-manager.service.ts
// Path: /flare-ui/src/app/services/locale-manager.service.ts

import { Injectable } from '@angular/core';
import { HttpClient, HttpHeaders, HttpErrorResponse } from '@angular/common/http';
import { Observable, of, throwError } from 'rxjs';
import { map, catchError, retry, timeout } from 'rxjs/operators';
import { AuthService } from './auth.service';

export interface Locale {
  code: string;
  name: string;
  english_name: string;
}

export interface LocaleDetails extends Locale {
  native_name?: string;
  direction: string;
  date_format: string;
  time_format: string;
  datetime_format: string;
  currency: string;
  currency_symbol: string;
  decimal_separator: string;
  thousands_separator: string;
  week_starts_on: number;
  months?: string[];
  days?: string[];
  am_pm?: string[];
  common_phrases?: { [key: string]: string };
}

@Injectable({
  providedIn: 'root'
})
export class LocaleManagerService {
  private apiUrl = '/api';
  private adminUrl = `${this.apiUrl}/admin`;
  private localesCache?: Locale[];
  private cacheTimestamp?: number;
  private readonly CACHE_DURATION = 5 * 60 * 1000; // 5 minutes
  private readonly REQUEST_TIMEOUT = 10000; // 10 seconds

  constructor(
    private http: HttpClient,
    private authService: AuthService
  ) {}

  private getAuthHeaders(): HttpHeaders {
    const token = this.authService.getToken();
    if (!token) {
      throw new Error('No authentication token available');
    }
    
    return new HttpHeaders({
      'Authorization': `Bearer ${token}`,
      'Content-Type': 'application/json'
    });
  }

  getAvailableLocales(): Observable<Locale[]> {
    try {
      // Check cache validity
      if (this.localesCache && this.cacheTimestamp) {
        const now = Date.now();
        if (now - this.cacheTimestamp < this.CACHE_DURATION) {
          return of(this.localesCache);
        }
      }

      return this.http.get<{ locales: Locale[], default: string }>(
        `${this.adminUrl}/locales`,
        { headers: this.getAuthHeaders() }
      ).pipe(
        timeout(this.REQUEST_TIMEOUT),
        retry({ count: 2, delay: 1000 }),
        map(response => {
          this.localesCache = response.locales;
          this.cacheTimestamp = Date.now();
          return response.locales;
        }),
        catchError(error => this.handleError(error, 'getAvailableLocales'))
      );
    } catch (error) {
      return this.handleError(error, 'getAvailableLocales');
    }
  }

  getLocaleDetails(code: string): Observable<LocaleDetails | null> {
    if (!code) {
      return throwError(() => new Error('Locale code is required'));
    }

    try {
      return this.http.get<LocaleDetails>(
        `${this.adminUrl}/locales/${encodeURIComponent(code)}`,
        { headers: this.getAuthHeaders() }
      ).pipe(
        timeout(this.REQUEST_TIMEOUT),
        retry({ count: 2, delay: 1000 }),
        catchError(error => {
          // For 404, return null instead of throwing
          if (error.status === 404) {
            console.warn(`Locale '${code}' not found`);
            return of(null);
          }
          return this.handleError(error, 'getLocaleDetails');
        })
      );
    } catch (error) {
      return this.handleError(error, 'getLocaleDetails');
    }
  }

  validateLanguages(languages: string[]): Observable<string[]> {
    if (!languages || languages.length === 0) {
      return of([]);
    }

    try {
      return this.getAvailableLocales().pipe(
        map(locales => {
          const availableCodes = locales.map(l => l.code);
          const invalidLanguages = languages.filter(lang => !availableCodes.includes(lang));
          
          if (invalidLanguages.length > 0) {
            console.warn('Invalid languages detected:', invalidLanguages);
          }
          
          return invalidLanguages;
        }),
        catchError(error => {
          console.error('Error validating languages:', error);
          // Return all languages as invalid if validation fails
          return of(languages);
        })
      );
    } catch (error) {
      return this.handleError(error, 'validateLanguages');
    }
  }

  clearCache(): void {
    this.localesCache = undefined;
    this.cacheTimestamp = undefined;
  }

  private handleError(error: any, operation: string): Observable<any> {
    console.error(`LocaleManagerService.${operation} error:`, error);

    // Handle authentication errors
    if (error?.status === 401) {
      this.authService.logout();
      return throwError(() => ({
        ...error,
        message: 'Authentication required'
      }));
    }

    // Handle race condition errors
    if (error?.status === 409) {
      return throwError(() => ({
        ...error,
        message: error.error?.message || 'Resource was modified by another user',
        isRaceCondition: true
      }));
    }

    // Handle network errors
    if (error?.status === 0 || error?.name === 'TimeoutError') {
      return throwError(() => ({
        ...error,
        message: 'Network connection error',
        isNetworkError: true
      }));
    }

    // For specific operations, provide fallback data
    if (operation === 'getAvailableLocales' && !error?.status) {
      // Fallback locales if API fails
      const fallback = [
        { code: 'tr-TR', name: 'Türkçe', english_name: 'Turkish' },
        { code: 'en-US', name: 'English', english_name: 'English (US)' }
      ];
      this.localesCache = fallback;
      this.cacheTimestamp = Date.now();
      console.warn('Using fallback locales due to error');
      return of(fallback);
    }

    // Default error handling
    const errorMessage = error?.error?.message || error?.message || 'Unknown error occurred';
    return throwError(() => ({
      ...error,
      message: errorMessage,
      operation: operation,
      timestamp: new Date().toISOString()
    }));
  }

  // Helper method to check if cache is stale
  isCacheStale(): boolean {
    if (!this.cacheTimestamp) return true;
    return Date.now() - this.cacheTimestamp > this.CACHE_DURATION;
  }

  // Force refresh locales
  refreshLocales(): Observable<Locale[]> {
    this.clearCache();
    return this.getAvailableLocales();
  }
}