From 527a8cc9c5f1650accf0ffbe9cc7110bdb6b3af1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Philip=20Dub=C3=A9?= <philip@peerdb.io>
Date: Sun, 13 Oct 2024 06:23:51 +0000
Subject: [PATCH] feat: infer Decimal

---
 proto/col_auto.go      | 44 ++++++++++++++++++++++++++++++++++++++++++
 proto/col_auto_test.go | 11 +++++++++++
 proto/column.go        |  1 +
 3 files changed, 56 insertions(+)

diff --git a/proto/col_auto.go b/proto/col_auto.go
index bda616be..c72615da 100644
--- a/proto/col_auto.go
+++ b/proto/col_auto.go
@@ -1,6 +1,7 @@
 package proto
 
 import (
+	"strconv"
 	"strings"
 
 	"github.com/go-faster/errors"
@@ -74,6 +75,49 @@ func (c *ColAuto) Infer(t ColumnType) error {
 			c.Data = v
 			c.DataType = t
 			return nil
+		case ColumnTypeDecimal:
+			var prec int
+			precStr, _, _ := strings.Cut(string(t.Elem()), ",")
+			if precStr != "" {
+				var err error
+				precStr = strings.TrimSpace(precStr)
+				prec, err = strconv.Atoi(precStr)
+				if err != nil {
+					return errors.Wrap(err, "decimal")
+				}
+			} else {
+				prec = 10
+			}
+			switch {
+			case prec >= 1 && prec < 10:
+				c.Data = new(ColDecimal32)
+			case prec >= 10 && prec < 19:
+				c.Data = new(ColDecimal64)
+			case prec >= 19 && prec < 39:
+				c.Data = new(ColDecimal128)
+			case prec >= 39 && prec < 77:
+				c.Data = new(ColDecimal256)
+			default:
+				return errors.Errorf("decimal precision %d out of range", prec)
+			}
+			c.DataType = t
+			return nil
+		case ColumnTypeDecimal32:
+			c.Data = new(ColDecimal32)
+			c.DataType = t
+			return nil
+		case ColumnTypeDecimal64:
+			c.Data = new(ColDecimal64)
+			c.DataType = t
+			return nil
+		case ColumnTypeDecimal128:
+			c.Data = new(ColDecimal128)
+			c.DataType = t
+			return nil
+		case ColumnTypeDecimal256:
+			c.Data = new(ColDecimal256)
+			c.DataType = t
+			return nil
 		case ColumnTypeEnum8, ColumnTypeEnum16:
 			v := new(ColEnum)
 			if err := v.Infer(t); err != nil {
diff --git a/proto/col_auto_test.go b/proto/col_auto_test.go
index a889fd11..5c0b3f4b 100644
--- a/proto/col_auto_test.go
+++ b/proto/col_auto_test.go
@@ -46,6 +46,17 @@ func TestColAuto_Infer(t *testing.T) {
 		ColumnTypeUUID,
 		ColumnTypeArray.Sub(ColumnTypeUUID),
 		ColumnTypeNullable.Sub(ColumnTypeUUID),
+		ColumnTypeDecimal,
+		ColumnTypeDecimal32,
+		ColumnTypeDecimal64,
+		ColumnTypeDecimal128,
+		ColumnTypeDecimal256,
+		"Decimal(2)",
+		"Decimal(20, 2)",
+		"Decimal32(1)",
+		"Decimal64(2)",
+		"Decimal128(3)",
+		"Decimal256(4)",
 	} {
 		r := AutoResult("foo")
 		require.NoError(t, r.Data.(Inferable).Infer(columnType))
diff --git a/proto/column.go b/proto/column.go
index cc734234..00d4123a 100644
--- a/proto/column.go
+++ b/proto/column.go
@@ -207,6 +207,7 @@ const (
 	ColumnTypeBool           ColumnType = "Bool"
 	ColumnTypeTuple          ColumnType = "Tuple"
 	ColumnTypeNullable       ColumnType = "Nullable"
+	ColumnTypeDecimal        ColumnType = "Decimal"
 	ColumnTypeDecimal32      ColumnType = "Decimal32"
 	ColumnTypeDecimal64      ColumnType = "Decimal64"
 	ColumnTypeDecimal128     ColumnType = "Decimal128"