fayda-auth/src/index.ts

A library for interacting with the Fayda authentication service.

import axios, { AxiosInstance, isAxiosError } from 'axios';
import { FaydaAuthOptions, InitiateOTPResponse, VerifyOTPResponse, ApiError } from './types/index';
import { FaydaAuthError } from './FaydaAuthError';

export class FaydaAuth {
    private apiKey: string;
    private client: AxiosInstance;

    constructor(options: FaydaAuthOptions) {
        if (!options.apiKey) {
            throw new FaydaAuthError({
                success: false,
                error: 'MISSING_API_KEY',
                message: 'API key is required.',
                statusCode: 401,
                timestamp: new Date().toISOString()
            });
        }
        this.apiKey = options.apiKey;
        this.client = axios.create({
            baseURL: options.baseUrl || 'https://fayda-auth.vercel.app/api/fayda',
            headers: {
                'Authorization': `Bearer ${this.apiKey}`,
                'Content-Type': 'application/json'
            }
        });
    }

    private handleError(error: unknown): never {
        if (isAxiosError(error) && error.response) {
            const apiError = error.response.data as ApiError;
            if (apiError && apiError.error) {
                throw new FaydaAuthError(apiError);
            }
        }
        // Generic error for when the API doesn't return a standard error format
        throw new FaydaAuthError({
            success: false,
            error: 'UNKNOWN_ERROR',
            message: 'An unexpected error occurred. Please try again later.',
            statusCode: 500,
            timestamp: new Date().toISOString(),
            details: { originalError: error instanceof Error ? error.message : String(error) }
        });
    }

    async initiateOTP(fcn: string): Promise<InitiateOTPResponse> {
        try {
            const response = await this.client.post<InitiateOTPResponse>('/otp/initiate', { fcn });
            return response.data;
        } catch (error) {
            this.handleError(error);
        }
    }

    async verifyOTP(transactionId: string, otp: string, fcn: string): Promise<VerifyOTPResponse> {
        try {
            const response = await this.client.post<VerifyOTPResponse>('/otp/verify', { transactionId, otp, fcn });
            return response.data;
        } catch (error) {
            this.handleError(error);
        }
    }
}