Initial BTCPay integration

.env.example

@@ -1,3 +1,4 @@
 EJABBERD_API_URL='https://xmpp.kosmos.org/api'
+BTCPAY_API_URL='http://localhost:23001'
 LNDHUB_API_URL='http://localhost:3023'
 LNDHUB_PUBLIC_URL='https://lndhub.kosmos.org'

.env.production

@@ -1,3 +1,4 @@
 EJABBERD_API_URL='https://xmpp.kosmos.org:5443/api'
+BTCPAY_API_URL='http://10.1.1.163:23001'
 LNDHUB_API_URL='http://10.1.1.163:3023'
 LNDHUB_PUBLIC_URL='https://lndhub.kosmos.org'

app/services/btc_pay.rb

@@ -0,0 +1,32 @@
+#
+# API Docs: https://docs.btcpayserver.org/API/Greenfield/v1/
+#
+class BtcPay
+  def initialize
+    @base_url = "#{ENV["BTCPAY_API_URL"]}/api/v1"
+    @store_id = Rails.application.credentials.btcpay[:store_id]
+    @auth_token = Rails.application.credentials.btcpay[:auth_token]
+  end
+
+  def onchain_wallet_balance
+    wallet_info = get "stores/#{@store_id}/payment-methods/onchain/BTC/wallet"
+
+    {
+      balance: wallet_info["balance"].to_f,
+      unconfirmed_balance: wallet_info["unconfirmedBalance"].to_f,
+      confirmed_balance: wallet_info["confirmedBalance"].to_f
+    }
+  end
+
+  private
+
+  def get(endpoint)
+    res = Faraday.get("#{@base_url}/#{endpoint}", {}, {
+      "Content-Type" => "application/json",
+      "Accept" => "application/json",
+      "Authorization" => "token #{@auth_token}"
+    })
+
+    JSON.parse(res.body)
+  end
+end