Implement bitcoin donations via BTCPay

app/services/btcpay_manager/create_invoice.rb

@@ -0,0 +1,21 @@
+module BtcpayManager
+  class CreateInvoice < BtcpayManagerService
+    def initialize(amount:, currency:, redirect_url:)
+      @amount = amount
+      @currency = currency
+      @redirect_url = redirect_url
+    end
+
+    def call
+      post "/invoices", {
+        amount: @amount.to_s,
+        currency: @currency,
+        checkout: {
+          redirectURL: @redirect_url,
+          redirectAutomatically: true,
+          requiresRefundEmail: false
+        }
+      }
+    end
+  end
+end

app/services/btcpay_manager/fetch_exchange_rate.rb

@@ -0,0 +1,14 @@
+module BtcpayManager
+  class FetchExchangeRate < BtcpayManagerService
+    def initialize(fiat_currency:)
+      @fiat_currency = fiat_currency
+    end
+
+    def call
+      pair_str = "BTC_#{@fiat_currency}"
+      res = get "rates", { currencyPair: pair_str }
+      pair = res.find{|p| p["currencyPair"] == pair_str }
+      rate = pair["rate"].to_f
+    end
+  end
+end

app/services/btcpay_manager/fetch_invoice.rb

@@ -0,0 +1,14 @@
+module BtcpayManager
+  class FetchInvoice < BtcpayManagerService
+    def initialize(invoice_id:)
+      @invoice_id = invoice_id
+    end
+
+    def call
+      invoice = get "/invoices/#{@invoice_id}"
+      payment_methods = get "/invoices/#{@invoice_id}/payment-methods"
+      invoice["paymentMethods"] = payment_methods
+      invoice
+    end
+  end
+end

app/services/btcpay_manager_service.rb

@@ -24,8 +24,8 @@ class BtcpayManagerService < ApplicationService
       "#{base_url}/#{path.gsub(/^\//, '')}"
     end
 
-    def get(path)
-      res = Faraday.get endpoint_url(path), {}, headers
+    def get(path, params = {})
+      res = Faraday.get endpoint_url(path), params, headers
       JSON.parse(res.body)
     end