feat : add kbz merchant service

app/services/kbz_merchant.rb

@@ -0,0 +1,99 @@
+require 'httparty'
+
+class KbzMerchant
+  class PaymentError < StandardError; end
+
+  def initialize(payment_method)
+    @payment_method = payment_method
+    @api_url = payment_method.test_mode? ?
+        'http://api.kbzpay.com/payment/gateway/uat/precreate' :
+        'https://api.kbzpay.com/payment/gateway/precreate'
+  end
+
+  def create_order(transaction_params)
+    payload = build_payload(transaction_params)
+    response = send_request(payload)
+    handle_response(response)
+  end
+
+  private
+
+  def build_payload(params)
+    base_params = {
+      method: 'kbz.payment.precreate',
+      timestamp: Time.now.utc.to_i.to_s,
+      nonce_str: SecureRandom.hex(16),
+      notify_url: @payment_method.notify_url,
+      sign_type: 'SHA256',
+      version: '1.0',
+      biz_content: {
+        appid: @payment_method.appid,
+        merch_code: @payment_method.merch_code,
+        merch_order_id: params[:merch_order_id],
+        trade_type: 'PAY_BY_QRCODE',
+        total_amount: params[:total_amount].to_s,
+        trans_currency: 'MMK',
+        timeout_express: params[:timeout] || '120m'
+      }.compact
+    }
+
+    flattened = flatten_hash(base_params)
+    base_params.merge(sign: generate_signature(flattened))
+  end
+
+  def flatten_hash(hash, parent_key = nil)
+    hash.each_with_object({}) do |(k, v), res|
+      key = parent_key ? "#{k}" : k.to_s
+      if v.is_a?(Hash)
+        res.merge!(flatten_hash(v, key))
+      else
+        res[key] = v.to_s
+      end
+    end
+  end
+
+  def generate_signature(flattened_params)
+    key = 'uatfoodcourt@12'
+    sorted_params = flattened_params.except('sign', 'sign_type').sort
+    string_a = sorted_params.map { |k, v| "#{k}=#{v}" }.join('&')
+    puts "String a: #{string_a}"
+    string_to_sign = "#{string_a}&key=#{key}"
+    puts "String to sign: #{string_to_sign}"
+    Digest::SHA256.hexdigest(string_to_sign).upcase
+  end
+
+  def send_request(payload)
+    headers = {
+      'Content-Type' => 'application/json',
+      'User-Agent' => 'KBZPay/1.0'
+    }
+
+    puts "Headers: #{headers}"
+    puts "Payload: #{payload.to_json}"
+
+    begin
+     response = HTTParty.post(
+        @api_url,
+        headers: headers,
+        body: { Request: payload }.to_json,
+        timeout: 15
+      )
+
+    puts "Response: #{response}"
+    rescue HTTParty::Error => e
+      raise PaymentError, "HTTP error: #{e.message}"
+    rescue SocketError => e
+      raise PaymentError, "Network error: #{e.message}"
+    end
+  end
+
+
+  def handle_response(response)
+    json_response = JSON.parse(response.body)
+    if json_response.dig('Response', 'result') == 'SUCCESS'
+      json_response['Response']
+    else
+      raise PaymentError, "Payment failed: #{json_response['Response']['msg']}"
+    end
+  end
+end