From 980db529f13798b6af431bcf96d63fcf26491d29 Mon Sep 17 00:00:00 2001
From: jordi fita mas <jordi@tandem.blog>
Date: Thu, 23 Feb 2023 14:42:18 +0100
Subject: [PATCH] Fix to_price and parse_price for negative values

---
 deploy/parse_price.sql | 8 +++++++-
 deploy/to_price.sql    | 7 ++++++-
 test/parse_price.sql   | 8 +++++++-
 test/to_price.sql      | 8 +++++++-
 4 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/deploy/parse_price.sql b/deploy/parse_price.sql
index 7cdfe8b..600635c 100644
--- a/deploy/parse_price.sql
+++ b/deploy/parse_price.sql
@@ -11,7 +11,13 @@ declare
 	parts text[];
 	result int;
 	frac_part text;
+	sign int := 1;
 begin
+	if price like '-%' Then
+		sign := -1;
+		price := substring(price from 2);
+	end if;
+
 	parts := string_to_array(price, '.');
 	if array_length(parts, 1) > 2 then
 		raise invalid_parameter_value using message = price || ' is not a valid price representation.';	
@@ -31,7 +37,7 @@ begin
 		result := result + frac_part::integer;
 	end if;
 
-	return result;
+	return sign * result;
 end;
 $$
 language plpgsql
diff --git a/deploy/to_price.sql b/deploy/to_price.sql
index 0cc20bb..7cc5817 100644
--- a/deploy/to_price.sql
+++ b/deploy/to_price.sql
@@ -10,9 +10,14 @@ $$
 declare
 	result text;
 	scale integer := 10^decimal_digits;
+	sign text := '';
 begin
+	if cents < 0 then
+		sign := '-';
+		cents = -cents;
+	end if;
 	result = cents::text;
-	return (cents / scale)::text || '.' || to_char(mod(cents, scale), rpad('FM', decimal_digits + 2, '0'));
+	return sign || (cents / scale)::text || '.' || to_char(mod(cents, scale), rpad('FM', decimal_digits + 2, '0'));
 end;
 $$
 language plpgsql
diff --git a/test/parse_price.sql b/test/parse_price.sql
index 6317eca..9c42d98 100644
--- a/test/parse_price.sql
+++ b/test/parse_price.sql
@@ -5,7 +5,7 @@ reset client_min_messages;
 
 begin;
 
-select plan(36);
+select plan(42);
 
 set search_path to auth, numerus, public;
 
@@ -23,8 +23,12 @@ select is( parse_price('1.1', 2), 110 );
 select is( parse_price('1.1', 3), 1100 );
 select is( parse_price('0', 2), 0 );
 select is( parse_price('0', 3), 0 );
+select is( parse_price('-0', 2), 0 );
+select is( parse_price('-0', 3), 0 );
 select is( parse_price('0.01', 2), 1 );
 select is( parse_price('0.001', 3), 1 );
+select is( parse_price('-0.01', 2), -1 );
+select is( parse_price('-0.001', 3), -1 );
 select is( parse_price('0.1', 2), 10 );
 select is( parse_price('0.01', 3), 10 );
 select is( parse_price('1', 2), 100 );
@@ -33,6 +37,8 @@ select is( parse_price('10', 2), 1000 );
 select is( parse_price('1', 3), 1000 );
 select is( parse_price('23.23', 2), 2323 );
 select is( parse_price('23.23', 3), 23230 );
+select is( parse_price('-23.23', 2), -2323 );
+select is( parse_price('-23.23', 3), -23230 );
 select throws_ok( $$ select parse_price('234.234', 2) $$ );
 select is( parse_price('234.234', 3), 234234 );
 select throws_ok( $$ select parse_price('2345.2345', 2) $$ );
diff --git a/test/to_price.sql b/test/to_price.sql
index 2fbf443..ef71373 100644
--- a/test/to_price.sql
+++ b/test/to_price.sql
@@ -5,7 +5,7 @@ reset client_min_messages;
 
 begin;
 
-select plan(23);
+select plan(29);
 
 set search_path to numerus, public;
 
@@ -23,6 +23,8 @@ select is( to_price(0, 2), '0.00' );
 select is( to_price(0, 3), '0.000' );
 select is( to_price(1, 2), '0.01' );
 select is( to_price(1, 3), '0.001' );
+select is( to_price(-1, 2), '-0.01' );
+select is( to_price(-1, 3), '-0.001' );
 select is( to_price(10, 2), '0.10' );
 select is( to_price(10, 3), '0.010' );
 select is( to_price(100, 2), '1.00' );
@@ -33,6 +35,10 @@ select is( to_price(12345678, 2), '123456.78' );
 select is( to_price(12345678, 3), '12345.678' );
 select is( to_price(12345678, 4), '1234.5678' );
 select is( to_price(12345678, 5), '123.45678' );
+select is( to_price(-12345678, 2), '-123456.78' );
+select is( to_price(-12345678, 3), '-12345.678' );
+select is( to_price(-12345678, 4), '-1234.5678' );
+select is( to_price(-12345678, 5), '-123.45678' );
 
 select *
 from finish();