Imports System.Net.Http
Imports System.Net.Http.Headers
Imports System.Threading.Tasks

Public Class MerchantClient
    Private ReadOnly _httpClient As HttpClient
    Private ReadOnly _baseUrl As String = "https://your-api-domain.com"
    Private ReadOnly _bearerToken As String

    Public Sub New(bearerToken As String)
        _bearerToken = bearerToken
        _httpClient = New HttpClient()
        _httpClient.BaseAddress = New Uri(_baseUrl)
        _httpClient.DefaultRequestHeaders.Authorization = _
            New AuthenticationHeaderValue("Bearer", _bearerToken)
        _httpClient.DefaultRequestHeaders.Accept.Add( _
            New MediaTypeWithQualityHeaderValue("application/json"))
    End Sub

    Public Async Function GetMerchantAsync(merchantId As String) As Task(Of String)
        Try
            ' Validate merchant ID format
            If String.IsNullOrEmpty(merchantId) OrElse merchantId.Length <> 11 Then
                Throw New ArgumentException("Merchant ID must be 11 digits", NameOf(merchantId))
            End If

            ' Construct the endpoint URL
            Dim endpoint As String = $"/v1/rest/merchants/{merchantId}"

            ' Make the GET request
            Dim response As HttpResponseMessage = Await _httpClient.GetAsync(endpoint)

            ' Check response status
            If response.IsSuccessStatusCode Then
                Dim responseBody As String = Await response.Content.ReadAsStringAsync()
                Return responseBody
            ElseIf response.StatusCode = Net.HttpStatusCode.NotFound Then
                Throw New Exception($"Merchant {merchantId} not found")
            Else
                Throw New HttpRequestException($"Request failed with status: {response.StatusCode}")
            End If
        Catch ex As HttpRequestException
            Console.WriteLine($"Request error: {ex.Message}")
            Throw
        End Try
    End Function
End Class

' Example usage:
Dim client As New MerchantClient("your-bearer-token-here")
Dim merchantInfo As String = Await client.GetMerchantAsync("12345678901")
Console.WriteLine(merchantInfo)

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.time.Duration;

public class MerchantClient {
    private final HttpClient httpClient;
    private final String baseUrl;
    private final String bearerToken;

    public MerchantClient(String bearerToken) {
        this.bearerToken = bearerToken;
        this.baseUrl = "https://your-api-domain.com";
        this.httpClient = HttpClient.newBuilder()
            .connectTimeout(Duration.ofSeconds(10))
            .build();
    }

    public String getMerchant(String merchantId) throws Exception {
        // Validate merchant ID format
        if (merchantId == null || merchantId.length() != 11) {
            throw new IllegalArgumentException("Merchant ID must be 11 digits");
        }

        // Construct the endpoint URL
        String endpoint = baseUrl + "/v1/rest/merchants/" + merchantId;

        // Build the HTTP request
        HttpRequest request = HttpRequest.newBuilder()
            .uri(URI.create(endpoint))
            .header("Authorization", "Bearer " + bearerToken)
            .header("Accept", "application/json")
            .GET()
            .build();

        // Send the request and get response
        HttpResponse<String> response = httpClient.send(
            request,
            HttpResponse.BodyHandlers.ofString()
        );

        // Check response status
        if (response.statusCode() == 200) {
            return response.body();
        } else if (response.statusCode() == 404) {
            throw new Exception("Merchant " + merchantId + " not found");
        } else {
            throw new Exception("Request failed with status: " + response.statusCode());
        }
    }

    // Example usage
    public static void main(String[] args) {
        try {
            MerchantClient client = new MerchantClient("your-bearer-token-here");
            String merchantInfo = client.getMerchant("12345678901");
            System.out.println(merchantInfo);
        } catch (Exception e) {
            System.err.println("Error: " + e.getMessage());
            e.printStackTrace();
        }
    }
}

require 'net/http'
require 'uri'
require 'json'

class MerchantClient
  def initialize(bearer_token, base_url = 'https://your-api-domain.com')
    @bearer_token = bearer_token
    @base_url = base_url
  end

  def get_merchant(merchant_id)
    # Validate merchant ID format
    raise ArgumentError, 'Merchant ID must be 11 digits' unless merchant_id&.length == 11

    # Construct the endpoint URL
    uri = URI("#{@base_url}/v1/rest/merchants/#{merchant_id}")

    # Create HTTP request
    http = Net::HTTP.new(uri.host, uri.port)
    http.use_ssl = true if uri.scheme == 'https'
    http.read_timeout = 30

    request = Net::HTTP::Get.new(uri.path)
    request['Authorization'] = "Bearer #{@bearer_token}"
    request['Accept'] = 'application/json'

    # Send request and handle response
    response = http.request(request)

    case response.code.to_i
    when 200
      JSON.parse(response.body)
    when 404
      raise "Merchant #{merchant_id} not found"
    else
      raise "Request failed with status: #{response.code} - #{response.message}"
    end
  rescue StandardError => e
    puts "Request error: #{e.message}"
    raise
  end
end

# Example usage:
client = MerchantClient.new('your-bearer-token-here')
merchant_info = client.get_merchant('12345678901')
puts JSON.pretty_generate(merchant_info)

end

def get_merchant(merchant_id)
# Validate merchant ID format
raise ArgumentError, 'Merchant ID must be 11 digits' unless merchant_id&.length == 11

# Construct the endpoint URL
uri = URI("#{@base_url}/v1/rest/merchants/#{merchant_id}")

# Create HTTP request
http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = true if uri.scheme == 'https'
http.read_timeout = 30

request = Net::HTTP::Get.new(uri.path)
request['Authorization'] = "Bearer #{@bearer_token}"
request['Accept'] = 'application/json'

# Send request and handle response
response = http.request(request)

case response.code.to_i
when 200
JSON.parse(response.body)
when 404
raise "Merchant #{merchant_id} not found"
else
raise "Request failed with status: #{response.code} - #{response.message}"
end
rescue StandardError => e
puts "Request error: #{e.message}"
raise
end
end

# Example usage:
client = MerchantClient.new('your-bearer-token-here')
merchant_info = client.get_merchant('12345678901')
puts JSON.pretty_generate(merchant_info)