From ea173eb3cc3beac3a1170260995c5f5d59faf99d Mon Sep 17 00:00:00 2001
From: Chris Schinnerl <chris@sia.tech>
Date: Wed, 14 Feb 2024 16:08:48 +0100
Subject: [PATCH] stores: binary currency type

---
 stores/metadata_test.go | 61 +++++++++++++++++++++++++++++++++++++++++
 stores/types.go         | 28 +++++++++++++++++++
 2 files changed, 89 insertions(+)

diff --git a/stores/metadata_test.go b/stores/metadata_test.go
index 96b06c4ec..0b0a696a5 100644
--- a/stores/metadata_test.go
+++ b/stores/metadata_test.go
@@ -6,8 +6,10 @@ import (
 	"encoding/hex"
 	"errors"
 	"fmt"
+	"math"
 	"os"
 	"reflect"
+	"sort"
 	"strings"
 	"testing"
 	"time"
@@ -4284,3 +4286,62 @@ func TestUpdateObjectReuseSlab(t *testing.T) {
 		}
 	}
 }
+
+func TestTypeCurrency(t *testing.T) {
+	ss := newTestSQLStore(t, defaultTestSQLStoreConfig)
+	defer ss.Close()
+
+	tests := []struct {
+		a   types.Currency
+		b   types.Currency
+		cmp string
+	}{
+		{
+			a:   types.ZeroCurrency,
+			b:   types.NewCurrency64(1),
+			cmp: "<",
+		},
+		{
+			a:   types.NewCurrency64(1),
+			b:   types.NewCurrency64(1),
+			cmp: "=",
+		},
+		{
+			a:   types.NewCurrency(0, math.MaxUint64),
+			b:   types.NewCurrency(math.MaxUint64, 0),
+			cmp: "<",
+		},
+		{
+			a:   types.NewCurrency(math.MaxUint64, 0),
+			b:   types.NewCurrency(0, math.MaxUint64),
+			cmp: ">",
+		},
+	}
+	for _, test := range tests {
+		var result bool
+		err := ss.db.Raw("SELECT ? "+test.cmp+" ?", bCurrency(test.a), bCurrency(test.b)).Scan(&result).Error
+		if err != nil {
+			t.Fatal(err)
+		} else if !result {
+			t.Fatal("unexpected result", result)
+		}
+	}
+
+	c := func(c uint64) bCurrency {
+		return bCurrency(types.NewCurrency64(c))
+	}
+
+	var currencies []bCurrency
+	err := ss.db.Raw(`
+WITH input(col) as
+(values (?),(?),(?))
+SELECT * FROM input ORDER BY col ASC
+`, c(3), c(1), c(2)).Scan(&currencies).Error
+	if err != nil {
+		t.Fatal(err)
+	} else if !sort.SliceIsSorted(currencies, func(i, j int) bool {
+		return types.Currency(currencies[i]).Cmp(types.Currency(currencies[j])) < 0
+	}) {
+		t.Fatal("currencies not sorted", currencies)
+	}
+}
diff --git a/stores/types.go b/stores/types.go
index 6b74f7563..9a7c72009 100644
--- a/stores/types.go
+++ b/stores/types.go
@@ -2,6 +2,7 @@ package stores
 
 import (
 	"database/sql/driver"
+	"encoding/binary"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -25,6 +26,7 @@ type (
 	unixTimeMS     time.Time
 	datetime       time.Time
 	currency       types.Currency
+	bCurrency      types.Currency
 	fileContractID types.FileContractID
 	hash256        types.Hash256
 	publicKey      types.PublicKey
@@ -338,3 +340,29 @@ func (u *unsigned64) Scan(value interface{}) error {
 func (u unsigned64) Value() (driver.Value, error) {
 	return int64(u), nil
 }
+
+func (bCurrency) GormDataType() string {
+	return "bytes"
+}
+
+// Scan implements the sql.Scanner interface.
+func (sc *bCurrency) Scan(src any) error {
+	buf, ok := src.([]byte)
+	if !ok {
+		return fmt.Errorf("cannot scan %T to Currency", src)
+	} else if len(buf) != 16 {
+		return fmt.Errorf("cannot scan %d bytes to Currency", len(buf))
+	}
+
+	sc.Lo = binary.LittleEndian.Uint64(buf[:8])
+	sc.Hi = binary.LittleEndian.Uint64(buf[8:])
+	return nil
+}
+
+// Value implements the driver.Valuer interface.
+func (sc bCurrency) Value() (driver.Value, error) {
+	buf := make([]byte, 16)
+	binary.LittleEndian.PutUint64(buf[:8], sc.Lo)
+	binary.LittleEndian.PutUint64(buf[8:], sc.Hi)
+	return buf, nil
+}