process_pending_btc_transactions

  1#!/usr/bin/ruby
  2# frozen_string_literal: true
  3
  4# Usage: bin/process_pending-btc_transactions '{
  5#        healthchecks_url = "https://hc-ping.com/...",
  6#        oxr_app_id = "",
  7#        required_confirmations = 3,
  8#        notify_using = {
  9#          jid = "",
 10#          password = "",
 11#          target = \(jid: Text) -> "+12266669977@cheogram.com",
 12#          body = \(jid: Text) -> \(body: Text) -> "/msg ${jid} ${body}",
 13#        },
 14#        electrum = env:ELECTRUM_CONFIG,
 15#        plans = ./plans.dhall,
 16#        activation_amount = 10000
 17#        }'
 18
 19require "bigdecimal"
 20require "dhall"
 21require "money/bank/open_exchange_rates_bank"
 22require "net/http"
 23require "nokogiri"
 24require "pg"
 25require "redis"
 26
 27require_relative "../lib/blather_notify"
 28require_relative "../lib/electrum"
 29
 30CONFIG =
 31	Dhall::Coder
 32	.new(safe: Dhall::Coder::JSON_LIKE + [Symbol, Proc])
 33	.load(ARGV[0], transform_keys: :to_sym)
 34
 35Net::HTTP.post_form(URI("#{CONFIG[:healthchecks_url]}/start"), {})
 36
 37REDIS = Redis.new
 38ELECTRUM = Electrum.new(**CONFIG[:electrum])
 39
 40DB = PG.connect(dbname: "jmp")
 41DB.type_map_for_results = PG::BasicTypeMapForResults.new(DB)
 42DB.type_map_for_queries = PG::BasicTypeMapForQueries.new(DB)
 43
 44BlatherNotify.start(
 45	CONFIG[:notify_using][:jid],
 46	CONFIG[:notify_using][:password]
 47)
 48
 49unless (cad_to_usd = REDIS.get("cad_to_usd")&.to_f)
 50	oxr = Money::Bank::OpenExchangeRatesBank.new(Money::RatesStore::Memory.new)
 51	oxr.app_id = CONFIG.fetch(:oxr_app_id)
 52	oxr.update_rates
 53	cad_to_usd = oxr.get_rate("CAD", "USD")
 54	REDIS.set("cad_to_usd", cad_to_usd, ex: 60*60)
 55end
 56
 57canadianbitcoins = Nokogiri::HTML.parse(
 58	Net::HTTP.get(URI("https://www.canadianbitcoins.com"))
 59)
 60
 61bitcoin_row = canadianbitcoins.at("#ticker > table > tbody > tr")
 62raise "Bitcoin row has moved" unless bitcoin_row.at("td").text == "Bitcoin"
 63
 64btc_sell_price = {}
 65btc_sell_price[:CAD] = BigDecimal.new(
 66	bitcoin_row.at("td:nth-of-type(3)").text.match(/^\$(\d+\.\d+)/)[1]
 67)
 68btc_sell_price[:USD] = btc_sell_price[:CAD] * cad_to_usd
 69
 70class Plan
 71	def self.for_customer(customer)
 72		row = DB.exec_params(<<-SQL, [customer.id]).first
 73			SELECT plan_name FROM customer_plans WHERE customer_id=$1 LIMIT 1
 74		SQL
 75		from_name(customer, row&.[]("plan_name"))
 76	end
 77
 78	def self.pending_for_customer(customer)
 79		from_name(
 80			customer,
 81			REDIS.get("pending_plan_for-#{customer.id}"),
 82			klass: Pending
 83		)
 84	end
 85
 86	def self.from_name(customer, plan_name, klass: Plan)
 87		return unless plan_name
 88		plan = CONFIG[:plans].find { |p| p[:name] == plan_name }
 89		klass.new(customer, plan) if plan
 90	end
 91
 92	def initialize(customer, plan)
 93		@customer = customer
 94		@plan = plan
 95	end
 96
 97	def name
 98		@plan[:name]
 99	end
100
101	def currency
102		@plan[:currency]
103	end
104
105	def bonus_for(fiat_amount, cad_to_usd)
106		bonus = (0.050167 * fiat_amount) - (currency == :CAD ? 1 : cad_to_usd)
107		return bonus.round(4, :floor) if bonus > 0
108	end
109
110	def price
111		BigDecimal.new(@plan[:monthly_price].to_i) * 0.0001
112	end
113
114	def insert(start:, expire:)
115		params = [@customer.id, name, start, expire]
116		DB.exec_params(<<-SQL, params)
117			INSERT INTO plan_log
118				(customer_id, plan_name, starts_at, expires_at)
119			VALUES
120				($1, $2, $3, $4)
121		SQL
122	end
123
124	def activate_any_pending_plan!; end
125
126	class Pending < Plan
127		def initialize(customer, plan)
128			super
129			@go_until = Date.today >> 1
130		end
131
132		def activation_amount
133			camnt = BigDecimal.new(CONFIG[:activation_amount].to_i) * 0.0001
134			[camnt, price].max
135		end
136
137		def activate_any_pending_plan!
138			if @customer.balance < activation_amount
139				@customer.notify(
140					"Your account could not be activated because your " \
141					"balance of $#{@customer.balance} is less that the " \
142					"required activation amount of $#{activation_amount}. " \
143					"Please buy more credit to have your account activated."
144				)
145			else
146				charge_insert_notify
147			end
148		end
149
150	protected
151
152		def charge_insert_notify
153			@customer.add_transaction(
154				"activate_#{name}_until_#{@go_until}",
155				-price,
156				"Activate pending plan"
157			)
158			insert(start: Date.today, expire: @go_until)
159			REDIS.del("pending_plan_for-#{@customer.id}")
160			@customer.notify("Your account has been activated")
161		end
162	end
163end
164
165class Customer
166	def initialize(customer_id)
167		@customer_id = customer_id
168	end
169
170	def id
171		@customer_id
172	end
173
174	def notify(body)
175		jid = REDIS.get("jmp_customer_jid-#{@customer_id}")
176		raise "No JID for #{customer_id}" unless jid
177		BlatherNotify.say(
178			CONFIG[:notify_using][:target].call(jid),
179			CONFIG[:notify_using][:body].call(jid, body)
180		)
181	end
182
183	def plan
184		Plan.for_customer(self) || pending_plan
185	end
186
187	def pending_plan
188		Plan.pending_for_customer(self)
189	end
190
191	def balance
192		result = DB.exec_params(<<-SQL, [@customer_id]).first&.[]("balance")
193			SELECT balance FROM balances WHERE customer_id=$1
194		SQL
195		result || BigDecimal.new(0)
196	end
197
198	def add_btc_credit(txid, btc_amount, fiat_amount, cad_to_usd)
199		add_transaction(txid, btc_amount, fiat_amount, "Bitcoin payment")
200		if (bonus = plan.bonus_for(fiat_amount, cad_to_usd))
201			add_transaction("bonus_for_#{txid}", bonus, "Bitcoin payment bonus")
202		end
203		notify_btc_credit(txid, btc_amount, fiat_amount, bonus)
204	end
205
206	def notify_btc_credit(txid, btc_amount, fiat_amount, bonus)
207		tx_hash, = txid.split("/", 2)
208		notify([
209			"Your Bitcoin transaction of #{btc_amount.to_s('F')} BTC ",
210			"has been added as $#{'%.4f' % fiat_amount} (#{plan.currency}) ",
211			("+ $#{'%.4f' % bonus} bonus " if bonus),
212			"to your account.\n(txhash: #{tx_hash})"
213		].compact.join)
214	end
215
216	def add_transaction(id, amount, note)
217		DB.exec_params(<<-SQL, [@customer_id, id, amount, note])
218			INSERT INTO transactions
219				(customer_id, transaction_id, amount, note)
220			VALUES
221					($1, $2, $3, $4)
222			ON CONFLICT (transaction_id) DO NOTHING
223		SQL
224	end
225end
226
227REDIS.hgetall("pending_btc_transactions").each do |(txid, customer_id)|
228	tx_hash, address = txid.split("/", 2)
229	transaction = ELECTRUM.gettransaction(tx_hash)
230	next unless transaction.confirmations >= CONFIG[:required_confirmations]
231	btc = transaction.amount_for(address)
232	if btc <= 0
233		warn "Transaction shows as #{btc}, skipping #{txid}"
234		next
235	end
236	DB.transaction do
237		customer = Customer.new(customer_id)
238		if (plan = customer.plan)
239			amount = btc * btc_sell_price.fetch(plan.currency).round(4, :floor)
240			customer.add_btc_credit(txid, btc, amount, cad_to_usd)
241			customer.plan.activate_any_pending_plan!
242			REDIS.hdel("pending_btc_transactions", txid)
243		else
244			warn "No plan for #{customer_id} cannot save #{txid}"
245		end
246	end
247end
248
249Net::HTTP.post_form(URI(CONFIG[:healthchecks_url].to_s), {})