#!/usr/bin/ruby
# frozen_string_literal: true

# Usage: bin/process_pending-btc_transactions '{
#        healthchecks_url = "https://hc-ping.com/...",
#        oxr_app_id = "",
#        required_confirmations = 3,
#        notify_using = {
#          jid = "",
#          password = "",
#          target = \(jid: Text) -> "+12266669977@cheogram.com",
#          body = \(jid: Text) -> \(body: Text) -> "/msg ${jid} ${body}",
#        },
#        electrum = env:ELECTRUM_CONFIG,
#        plans = ./plans.dhall,
#        activation_amount = 10000
#        }'

require "bigdecimal"
require "dhall"
require "money/bank/open_exchange_rates_bank"
require "net/http"
require "nokogiri"
require "pg"
require "redis"

require_relative "../lib/blather_notify"
require_relative "../lib/electrum"

CONFIG =
	Dhall::Coder
	.new(safe: Dhall::Coder::JSON_LIKE + [Symbol, Proc])
	.load(ARGV[0], transform_keys: :to_sym)

Net::HTTP.post_form(URI("#{CONFIG[:healthchecks_url]}/start"), {})

REDIS = Redis.new
ELECTRUM = Electrum.new(**CONFIG[:electrum])

DB = PG.connect(dbname: "jmp")
DB.type_map_for_results = PG::BasicTypeMapForResults.new(DB)
DB.type_map_for_queries = PG::BasicTypeMapForQueries.new(DB)

BlatherNotify.start(
	CONFIG[:notify_using][:jid],
	CONFIG[:notify_using][:password]
)

unless (cad_to_usd = REDIS.get("cad_to_usd")&.to_f)
	oxr = Money::Bank::OpenExchangeRatesBank.new(Money::RatesStore::Memory.new)
	oxr.app_id = CONFIG.fetch(:oxr_app_id)
	oxr.update_rates
	cad_to_usd = oxr.get_rate("CAD", "USD")
	REDIS.set("cad_to_usd", cad_to_usd, ex: 60*60)
end

canadianbitcoins = Nokogiri::HTML.parse(
	Net::HTTP.get(URI("https://www.canadianbitcoins.com"))
)

bitcoin_row = canadianbitcoins.at("#ticker > table > tbody > tr")
raise "Bitcoin row has moved" unless bitcoin_row.at("td").text == "Bitcoin"

btc_sell_price = {}
btc_sell_price[:CAD] = BigDecimal.new(
	bitcoin_row.at("td:nth-of-type(3)").text.match(/^\$(\d+\.\d+)/)[1]
)
btc_sell_price[:USD] = btc_sell_price[:CAD] * cad_to_usd

class Plan
	def self.for_customer(customer)
		row = DB.exec_params(<<-SQL, [customer.id]).first
			SELECT plan_name FROM customer_plans WHERE customer_id=$1 LIMIT 1
		SQL
		from_name(customer, row&.[]("plan_name"))
	end

	def self.pending_for_customer(customer)
		from_name(
			customer,
			REDIS.get("pending_plan_for-#{customer.id}"),
			klass: Pending
		)
	end

	def self.from_name(customer, plan_name, klass: Plan)
		return unless plan_name
		plan = CONFIG[:plans].find { |p| p[:name] == plan_name }
		klass.new(customer, plan) if plan
	end

	def initialize(customer, plan)
		@customer = customer
		@plan = plan
	end

	def name
		@plan[:name]
	end

	def currency
		@plan[:currency]
	end

	def bonus_for(fiat_amount, cad_to_usd)
		bonus = (0.050167 * fiat_amount) - (currency == :CAD ? 1 : cad_to_usd)
		return bonus.round(4, :floor) if bonus > 0
	end

	def price
		BigDecimal.new(@plan[:monthly_price].to_i) * 0.0001
	end

	def insert(start:, expire:)
		params = [@customer.id, name, start, expire]
		DB.exec_params(<<-SQL, params)
			INSERT INTO plan_log
				(customer_id, plan_name, starts_at, expires_at)
			VALUES
				($1, $2, $3, $4)
		SQL
	end

	def activate_any_pending_plan!; end

	class Pending < Plan
		def initialize(customer, plan)
			super
			@go_until = Date.today >> 1
		end

		def activation_amount
			camnt = BigDecimal.new(CONFIG[:activation_amount].to_i) * 0.0001
			[camnt, price].max
		end

		def activate_any_pending_plan!
			if @customer.balance < activation_amount
				@customer.notify(
					"Your account could not be activated because your " \
					"balance of $#{@customer.balance} is less that the " \
					"required activation amount of $#{activation_amount}. " \
					"Please buy more credit to have your account activated."
				)
			else
				charge_insert_notify
			end
		end

	protected

		def charge_insert_notify
			@customer.add_transaction(
				"activate_#{name}_until_#{@go_until}",
				-price,
				"Activate pending plan"
			)
			insert(start: Date.today, expire: @go_until)
			REDIS.del("pending_plan_for-#{@customer.id}")
			@customer.notify("Your account has been activated")
		end
	end
end

class Customer
	def initialize(customer_id)
		@customer_id = customer_id
	end

	def id
		@customer_id
	end

	def notify(body)
		jid = REDIS.get("jmp_customer_jid-#{@customer_id}")
		raise "No JID for #{customer_id}" unless jid
		BlatherNotify.say(
			CONFIG[:notify_using][:target].call(jid),
			CONFIG[:notify_using][:body].call(jid, body)
		)
	end

	def plan
		Plan.for_customer(self) || pending_plan
	end

	def pending_plan
		Plan.pending_for_customer(self)
	end

	def balance
		result = DB.exec_params(<<-SQL, [@customer_id]).first&.[]("balance")
			SELECT balance FROM balances WHERE customer_id=$1
		SQL
		result || BigDecimal.new(0)
	end

	def add_btc_credit(txid, btc_amount, fiat_amount, cad_to_usd)
		add_transaction(txid, btc_amount, fiat_amount, "Bitcoin payment")
		if (bonus = plan.bonus_for(fiat_amount, cad_to_usd))
			add_transaction("bonus_for_#{txid}", bonus, "Bitcoin payment bonus")
		end
		notify_btc_credit(txid, btc_amount, fiat_amount, bonus)
	end

	def notify_btc_credit(txid, btc_amount, fiat_amount, bonus)
		tx_hash, = txid.split("/", 2)
		notify([
			"Your Bitcoin transaction of #{btc_amount.to_s('F')} BTC ",
			"has been added as $#{'%.4f' % fiat_amount} (#{plan.currency}) ",
			("+ $#{'%.4f' % bonus} bonus " if bonus),
			"to your account.\n(txhash: #{tx_hash})"
		].compact.join)
	end

	def add_transaction(id, amount, note)
		DB.exec_params(<<-SQL, [@customer_id, id, amount, note])
			INSERT INTO transactions
				(customer_id, transaction_id, amount, note)
			VALUES
					($1, $2, $3, $4)
			ON CONFLICT (transaction_id) DO NOTHING
		SQL
	end
end

REDIS.hgetall("pending_btc_transactions").each do |(txid, customer_id)|
	tx_hash, address = txid.split("/", 2)
	transaction = ELECTRUM.gettransaction(tx_hash)
	next unless transaction.confirmations >= CONFIG[:required_confirmations]
	btc = transaction.amount_for(address)
	if btc <= 0
		warn "Transaction shows as #{btc}, skipping #{txid}"
		next
	end
	DB.transaction do
		customer = Customer.new(customer_id)
		if (plan = customer.plan)
			amount = btc * btc_sell_price.fetch(plan.currency).round(4, :floor)
			customer.add_btc_credit(txid, btc, amount, cad_to_usd)
			customer.plan.activate_any_pending_plan!
			REDIS.hdel("pending_btc_transactions", txid)
		else
			warn "No plan for #{customer_id} cannot save #{txid}"
		end
	end
end

Net::HTTP.post_form(URI(CONFIG[:healthchecks_url].to_s), {})