added apiClient class handling api auth and validation response from backend

frontend/src/services/apiClient.ts

@@ -0,0 +1,130 @@
+import { ValidationError, ErrorService } from './errorService';
+
+export class ApiError extends Error {
+  public validationErrors: ValidationError[];
+  public statusCode: number;
+  public originalError?: any;
+
+  constructor(message: string, validationErrors: ValidationError[] = [], statusCode: number = 0, originalError?: any) {
+    super(message);
+    this.name = 'ApiError';
+    this.validationErrors = validationErrors;
+    this.statusCode = statusCode;
+    this.originalError = originalError;
+  }
+}
+
+export class ApiClient {
+  private baseURL: string;
+
+  constructor() {
+    this.baseURL = import.meta.env.VITE_API_URL || '/api';
+  }
+
+  private getAuthHeaders(): HeadersInit {
+    const token = localStorage.getItem('token');
+    return token ? { 'Authorization': `Bearer ${token}` } : {};
+  }
+
+  private async handleApiResponse<T>(response: Response): Promise<T> {
+    if (!response.ok) {
+      let errorData;
+      
+      try {
+        // Try to parse error response as JSON
+        const responseText = await response.text();
+        errorData = responseText ? JSON.parse(responseText) : {};
+      } catch {
+        // If not JSON, create a generic error object
+        errorData = { error: `HTTP ${response.status}: ${response.statusText}` };
+      }
+      
+      // Extract validation errors using your existing ErrorService
+      const validationErrors = ErrorService.extractValidationErrors(errorData);
+
+      if (validationErrors.length > 0) {
+        // Throw error with validationErrors property for useBackendValidation hook
+        throw new ApiError(
+          errorData.error || 'Validation failed',
+          validationErrors,
+          response.status,
+          errorData
+        );
+      }
+
+      // Throw regular error for non-validation errors
+      throw new ApiError(
+        errorData.error || errorData.message || `HTTP error! status: ${response.status}`,
+        [],
+        response.status,
+        errorData
+      );
+    }
+
+    // For successful responses, try to parse as JSON
+    try {
+      const responseText = await response.text();
+      return responseText ? JSON.parse(responseText) : {} as T;
+    } catch (error) {
+      // If response is not JSON but request succeeded (e.g., 204 No Content)
+      return {} as T;
+    }
+  }
+
+  async request<T>(endpoint: string, options: RequestInit = {}): Promise<T> {
+    const url = `${this.baseURL}${endpoint}`;
+    
+    const config: RequestInit = {
+      headers: {
+        'Content-Type': 'application/json',
+        ...this.getAuthHeaders(),
+        ...options.headers,
+      },
+      ...options,
+    };
+
+    try {
+      const response = await fetch(url, config);
+      return await this.handleApiResponse<T>(response);
+    } catch (error) {
+      // Re-throw the error to be caught by useBackendValidation
+      if (error instanceof ApiError) {
+        throw error;
+      }
+      
+      // Wrap non-ApiError errors
+      throw new ApiError(
+        error instanceof Error ? error.message : 'Unknown error occurred',
+        [],
+        0,
+        error
+      );
+    }
+  }
+
+  // Standardized HTTP methods
+  get = <T>(endpoint: string) => this.request<T>(endpoint);
+  
+  post = <T>(endpoint: string, data?: any) => 
+    this.request<T>(endpoint, { 
+      method: 'POST', 
+      body: data ? JSON.stringify(data) : undefined 
+    });
+  
+  put = <T>(endpoint: string, data?: any) => 
+    this.request<T>(endpoint, { 
+      method: 'PUT', 
+      body: data ? JSON.stringify(data) : undefined 
+    });
+  
+  patch = <T>(endpoint: string, data?: any) => 
+    this.request<T>(endpoint, { 
+      method: 'PATCH', 
+      body: data ? JSON.stringify(data) : undefined 
+    });
+  
+  delete = <T>(endpoint: string) => 
+    this.request<T>(endpoint, { method: 'DELETE' });
+}
+
+export const apiClient = new ApiClient();