1# frozen_string_literal: true
 2
 3require "bigdecimal"
 4require "time"
 5require "value_semantics/monkey_patched"
 6
 7class Transaction
 8	value_semantics do
 9		customer_id String
10		transaction_id String
11		created_at Time, coerce: ->(x) { Time.parse(x.to_s) }
12		settled_after Time, coerce: ->(x) { Time.parse(x.to_s) }
13		amount BigDecimal, coerce: ->(x) { BigDecimal(x, 4) }
14		note String
15	end
16
17	def insert
18		EM.promise_fiber do
19			DB.transaction do
20				insert_tx
21				insert_bonus
22			end
23		end
24	end
25
26	def delete
27		ids = [@transaction_id, "bonus_for_#{@transaction_id}"]
28		DB.query_defer(<<~SQL, ids)
29			DELETE FROM transactions WHERE transaction_id IN ($1, $2)
30		SQL
31	end
32
33	def exists?
34		DB.query_one(<<~SQL, @transaction_id).then { |r| r[:count] == 1 }
35			SELECT COUNT(1) FROM transactions
36			WHERE transaction_id = $1
37		SQL
38	end
39
40	def total
41		amount + bonus
42	end
43
44	def bonus
45		return BigDecimal(0) if amount <= 15
46
47		amount *
48			case amount
49			when (15..29.99)
50				0.01
51			when (30..139.99)
52				0.03
53			else
54				0.05
55			end
56	end
57
58	def to_s
59		plus = " + #{'%.4f' % bonus} bonus"
60		"$#{'%.2f' % amount}#{plus if bonus.positive?}"
61	end
62
63protected
64
65	def insert_tx
66		params = [
67			@customer_id, @transaction_id, @created_at, @settled_after, @amount, @note
68		]
69		DB.exec(<<~SQL, params)
70			INSERT INTO transactions
71				(customer_id, transaction_id, created_at, settled_after, amount, note)
72			VALUES
73				($1, $2, $3, $4, $5, $6)
74		SQL
75	end
76
77	def insert_bonus
78		return if bonus <= 0
79
80		params = [
81			@customer_id, "bonus_for_#{@transaction_id}", @created_at,
82			@settled_after, bonus, "#{@note} bonus"
83		]
84		DB.exec(<<~SQL, params)
85			INSERT INTO transactions
86				(customer_id, transaction_id, created_at, settled_after, amount, note)
87			VALUES
88				($1, $2, $3, $4, $5, $6)
89		SQL
90	end
91end