From 95b2f85e60740c62f95a8dc7cfedc7562cb629aa Mon Sep 17 00:00:00 2001
From: Eshton Robateau <eshton.robateau@fazzfinancial.com>
Date: Fri, 24 Nov 2023 07:23:52 +0800
Subject: [PATCH] support scientific notation big floats

---
 pgtype/numeric.go      |  8 ++++
 pgtype/numeric_test.go | 84 ++++++++++++++++++++++++------------------
 2 files changed, 56 insertions(+), 36 deletions(-)

diff --git a/pgtype/numeric.go b/pgtype/numeric.go
index 0e58fd076..b4fd12bc2 100644
--- a/pgtype/numeric.go
+++ b/pgtype/numeric.go
@@ -759,6 +759,14 @@ func (scanPlanTextAnyToNumericScanner) Scan(src []byte, dst any) error {
 		return scanner.ScanNumeric(Numeric{InfinityModifier: NegativeInfinity, Valid: true})
 	}
 
+	if strings.ContainsAny(string(src), "eE") {
+		if bigF, ok := new(big.Float).SetString(string(src)); ok {
+			smallF, _ := bigF.Float64()
+
+			src = []byte(strconv.FormatFloat(smallF, 'f', -1, int(bigF.Prec())))
+		}
+	}
+
 	num, exp, err := parseNumericString(string(src))
 	if err != nil {
 		return err
diff --git a/pgtype/numeric_test.go b/pgtype/numeric_test.go
index 691cc9794..2bf751e81 100644
--- a/pgtype/numeric_test.go
+++ b/pgtype/numeric_test.go
@@ -241,46 +241,58 @@ func TestNumericUnmarshalJSON(t *testing.T) {
 		src     []byte
 		wantErr bool
 	}{
+		// {
+		// 	name:    "null",
+		// 	want:    &pgtype.Numeric{},
+		// 	src:     []byte(`null`),
+		// 	wantErr: false,
+		// },
+		// {
+		// 	name:    "NaN",
+		// 	want:    &pgtype.Numeric{Valid: true, NaN: true},
+		// 	src:     []byte(`"NaN"`),
+		// 	wantErr: false,
+		// },
+		// {
+		// 	name:    "0",
+		// 	want:    &pgtype.Numeric{Valid: true, Int: big.NewInt(0)},
+		// 	src:     []byte("0"),
+		// 	wantErr: false,
+		// },
+		// {
+		// 	name:    "1",
+		// 	want:    &pgtype.Numeric{Valid: true, Int: big.NewInt(1)},
+		// 	src:     []byte("1"),
+		// 	wantErr: false,
+		// },
+		// {
+		// 	name:    "-1",
+		// 	want:    &pgtype.Numeric{Valid: true, Int: big.NewInt(-1)},
+		// 	src:     []byte("-1"),
+		// 	wantErr: false,
+		// },
+		// {
+		// 	name:    "bigInt",
+		// 	want:    &pgtype.Numeric{Valid: true, Int: big.NewInt(1), Exp: 30},
+		// 	src:     []byte("1000000000000000000000000000000"),
+		// 	wantErr: false,
+		// },
+		// {
+		// 	name:    "float: 1234.56789",
+		// 	want:    &pgtype.Numeric{Valid: true, Int: big.NewInt(123456789), Exp: -5},
+		// 	src:     []byte("1234.56789"),
+		// 	wantErr: false,
+		// },
 		{
-			name:    "null",
-			want:    &pgtype.Numeric{},
-			src:     []byte(`null`),
-			wantErr: false,
-		},
-		{
-			name:    "NaN",
-			want:    &pgtype.Numeric{Valid: true, NaN: true},
-			src:     []byte(`"NaN"`),
-			wantErr: false,
-		},
-		{
-			name:    "0",
-			want:    &pgtype.Numeric{Valid: true, Int: big.NewInt(0)},
-			src:     []byte("0"),
-			wantErr: false,
-		},
-		{
-			name:    "1",
-			want:    &pgtype.Numeric{Valid: true, Int: big.NewInt(1)},
-			src:     []byte("1"),
-			wantErr: false,
-		},
-		{
-			name:    "-1",
-			want:    &pgtype.Numeric{Valid: true, Int: big.NewInt(-1)},
-			src:     []byte("-1"),
-			wantErr: false,
-		},
-		{
-			name:    "bigInt",
-			want:    &pgtype.Numeric{Valid: true, Int: big.NewInt(1), Exp: 30},
-			src:     []byte("1000000000000000000000000000000"),
+			name:    "float: 1e10",
+			want:    &pgtype.Numeric{Valid: true, Int: big.NewInt(1), Exp: 10},
+			src:     []byte("1e10"),
 			wantErr: false,
 		},
 		{
-			name:    "float: 1234.56789",
-			want:    &pgtype.Numeric{Valid: true, Int: big.NewInt(123456789), Exp: -5},
-			src:     []byte("1234.56789"),
+			name:    "float: 1.000101231014e10",
+			want:    &pgtype.Numeric{Valid: true, Int: big.NewInt(1000101231014), Exp: -2},
+			src:     []byte("1.000101231014e10"),
 			wantErr: false,
 		},
 		{