# frozen_string_literal: true

require "braintree"
require "date"
require "delegate"
require "dhall"
require "forwardable"
require "pg"
require "redis"
require "roda"
require "uri"

if ENV["RACK_ENV"] == "development"
	require "pry-rescue"
	use PryRescue::Rack
end

require_relative "lib/electrum"
require_relative "lib/transaction"

require "sentry-ruby"
Sentry.init do |config|
	config.traces_sample_rate = 1
end
use Sentry::Rack::CaptureExceptions

REDIS = Redis.new
PLANS = Dhall.load("env:PLANS").sync
BRAINTREE_CONFIG = Dhall.load("env:BRAINTREE_CONFIG").sync
ELECTRUM = Electrum.new(
	**Dhall::Coder.load("env:ELECTRUM_CONFIG", transform_keys: :to_sym)
)

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

class Plan
	def self.for(plan_name)
		new(PLANS.find { |p| p[:name].to_s == plan_name })
	end

	def initialize(plan)
		@plan = plan
	end

	def price(months=1)
		(BigDecimal(@plan[:monthly_price].to_i) * months) / 10000
	end

	def currency
		@plan[:currency].to_s.to_sym
	end

	def merchant_account
		BRAINTREE_CONFIG[:merchant_accounts][currency]
	end

	def self.active?(customer_id)
		DB.exec_params(<<~SQL, [customer_id]).first&.[]("count").to_i.positive?
			SELECT count(1) AS count FROM customer_plans
			WHERE customer_id=$1 AND expires_at > NOW()
		SQL
	end

	def bill_plan(customer_id)
		DB.transaction do
			charge_for_plan(customer_id)
			unless activate_plan_starting_now(customer_id)
				add_one_month_to_current_plan(customer_id)
			end
		end
		true
	end

	def activate_plan_starting_now(customer_id)
		DB.exec(<<~SQL, [customer_id, @plan[:name]]).cmd_tuples.positive?
			INSERT INTO plan_log
				(customer_id, plan_name, date_range)
			VALUES ($1, $2, tsrange(LOCALTIMESTAMP, LOCALTIMESTAMP + '1 month'))
			ON CONFLICT DO NOTHING
		SQL
	end

protected

	def charge_for_plan(customer_id)
		params = [
			customer_id,
			"#{customer_id}-bill-#{@plan[:name]}-at-#{Time.now.to_i}",
			-price
		]
		DB.exec(<<~SQL, params)
			INSERT INTO transactions
				(customer_id, transaction_id, created_at, amount)
			VALUES ($1, $2, LOCALTIMESTAMP, $3)
		SQL
	end

	def add_one_month_to_current_plan(customer_id)
		DB.exec(<<~SQL, [customer_id])
			UPDATE plan_log SET date_range=range_merge(
				date_range,
				tsrange(
					LOCALTIMESTAMP,
					GREATEST(upper(date_range), LOCALTIMESTAMP) + '1 month'
				)
			)
			WHERE
				customer_id=$1 AND
				date_range && tsrange(LOCALTIMESTAMP, LOCALTIMESTAMP + '1 month')
		SQL
	end
end

class CreditCardGateway
	def initialize(jid, customer_id=nil)
		@jid = jid
		@customer_id = customer_id

		@gateway = Braintree::Gateway.new(
			environment: BRAINTREE_CONFIG[:environment].to_s,
			merchant_id: BRAINTREE_CONFIG[:merchant_id].to_s,
			public_key: BRAINTREE_CONFIG[:public_key].to_s,
			private_key: BRAINTREE_CONFIG[:private_key].to_s
		)
	end

	def check_customer_id(cid)
		return cid unless ENV["RACK_ENV"] == "production"

		raise "customer_id does not match" unless @customer_id == cid

		cid
	end

	def customer_id
		customer_id = REDIS.get(redis_key_jid)
		return customer_id if check_customer_id(customer_id)

		result = @gateway.customer.create
		raise "Braintree customer create failed" unless result.success?

		@customer_id = result.customer.id
		save_customer_id!
	end

	def save_customer_id!
		unless REDIS.set(redis_key_jid, @customer_id) == "OK"
			raise "Saving new jid,customer to redis failed"
		end

		unless REDIS.set(redis_key_customer_id, @jid) == "OK"
			raise "Saving new customer,jid to redis failed"
		end

		@customer_id
	end

	def client_token
		@gateway.client_token.generate(customer_id: customer_id)
	end

	def payment_methods?
		!@gateway.customer.find(customer_id).payment_methods.empty?
	end

	def default_payment_method=(nonce)
		@gateway.payment_method.create(
			customer_id: customer_id,
			payment_method_nonce: nonce,
			options: {
				make_default: true
			}
		)
	end

	def decline_guard(ip)
		customer_declines, ip_declines = REDIS.mget(
			"jmp_pay_decline-#{@customer_id}",
			"jmp_pay_decline-#{ip}"
		)
		customer_declines.to_i < 2 && ip_declines.to_i < 4
	end

	def sale(ip:, **kwargs)
		return nil unless decline_guard(ip)

		tx = Transaction.sale(@gateway, **kwargs)
		return tx if tx

		REDIS.incr("jmp_pay_decline-#{@customer_id}")
		REDIS.expire("jmp_pay_decline-#{@customer_id}", 60 * 60 * 24)
		REDIS.incr("jmp_pay_decline-#{ip}")
		REDIS.expire("jmp_pay_decline-#{ip}", 60 * 60 * 24)
		nil
	end

	def buy_plan(plan_name, nonce, ip)
		plan = Plan.for(plan_name)
		sale(
			ip: ip,
			amount: plan.price(5),
			payment_method_nonce: nonce,
			merchant_account_id: plan.merchant_account,
			options: { submit_for_settlement: true }
		)&.insert && plan.bill_plan(@customer_id)
	end

protected

	def redis_key_jid
		"jmp_customer_id-#{@jid}"
	end

	def redis_key_customer_id
		"jmp_customer_jid-#{@customer_id}"
	end
end

class UnknownTransactions
	def self.from(customer_id, address, tx_hashes)
		self.for(
			customer_id,
			fetch_rows_for(address, tx_hashes).map { |row|
				row["transaction_id"]
			}
		)
	end

	def self.fetch_rows_for(address, tx_hashes)
		values = tx_hashes.map { |tx_hash|
			"('#{DB.escape_string(tx_hash)}/#{DB.escape_string(address)}')"
		}
		return [] if values.empty?

		DB.exec_params(<<-SQL)
			SELECT transaction_id FROM
				(VALUES #{values.join(',')}) AS t(transaction_id)
				LEFT JOIN transactions USING (transaction_id)
			WHERE transactions.transaction_id IS NULL
		SQL
	end

	def self.for(customer_id, transaction_ids)
		transaction_ids.empty? ? None.new : new(customer_id, transaction_ids)
	end

	def initialize(customer_id, transaction_ids)
		@customer_id = customer_id
		@transaction_ids = transaction_ids
	end

	def enqueue!
		REDIS.hset(
			"pending_btc_transactions",
			*@transaction_ids.flat_map { |txid| [txid, @customer_id] }
		)
	end

	class None
		def enqueue!; end
	end
end

class JmpPay < Roda
	SENTRY_DSN = ENV["SENTRY_DSN"] && URI(ENV["SENTRY_DSN"])
	plugin :render, engine: "slim"
	plugin :common_logger, $stdout

	extend Forwardable
	def_delegators :request, :params

	def redis_key_btc_addresses
		"jmp_customer_btc_addresses-#{params['customer_id']}"
	end

	def verify_address_customer_id(r)
		return if REDIS.sismember(redis_key_btc_addresses, params["address"])

		warn "Address and customer_id do not match"
		r.halt([
			403,
			{ "Content-Type" => "text/plain" },
			"Address and customer_id do not match"
		])
	end

	route do |r|
		r.on "electrum_notify" do
			verify_address_customer_id(r)

			UnknownTransactions.from(
				params["customer_id"],
				params["address"],
				ELECTRUM
					.getaddresshistory(params["address"])
					.map { |item| item["tx_hash"] }
			).enqueue!

			"OK"
		end

		r.on :jid do |jid|
			Sentry.set_user(id: params["customer_id"], jid: jid)

			gateway = CreditCardGateway.new(jid, params["customer_id"])
			topup = "jmp_customer_auto_top_up_amount-#{gateway.customer_id}"

			r.on "activate" do
				Sentry.configure_scope do |scope|
					scope.set_transaction_name("activate")
					scope.set_context(
						"activate",
						plan_name: params["plan_name"]
					)
				end

				render = lambda do |l={}|
					view(
						"activate",
						locals: {
							token: gateway.client_token,
							customer_id: gateway.customer_id,
							error: false
						}.merge(l)
					)
				end

				r.get do
					if Plan.active?(gateway.customer_id)
						r.redirect params["return_to"], 303
					else
						render.call
					end
				end

				r.post do
					result = DB.transaction {
						Plan.active?(gateway.customer_id) || gateway.buy_plan(
							params["plan_name"],
							params["braintree_nonce"],
							request.ip
						)
					}
					if params["auto_top_up_amount"].to_i >= 15
						REDIS.set(topup, params["auto_top_up_amount"].to_i)
					end
					if result
						r.redirect params["return_to"], 303
					else
						render.call(error: true)
					end
				end
			end

			r.on "credit_cards" do
				r.get do
					view(
						"credit_cards",
						locals: {
							token: gateway.client_token,
							customer_id: gateway.customer_id,
							auto_top_up: REDIS.get(topup) ||
							             (gateway.payment_methods? ? "" : "15")
						}
					)
				end

				r.post do
					gateway.default_payment_method = params["braintree_nonce"]
					if params["auto_top_up_amount"].to_i >= 15
						REDIS.set(topup, params["auto_top_up_amount"].to_i)
					elsif params["auto_top_up_amount"].to_i.zero?
						REDIS.del(topup)
					end
					"OK"
				end
			end
		end
	end
end

run JmpPay.freeze.app