Implement insert struct

server/internal/db/struct_query.go

@@ -0,0 +1,99 @@
+package db
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+	"unicode"
+)
+
+type DBField struct {
+	Name  string
+	Value any
+	Type  reflect.Type
+}
+
+func StructTagsToFields(s any) ([]DBField, error) {
+	v := reflect.ValueOf(s)
+
+	if v.Kind() == reflect.Ptr {
+		if v.IsNil() {
+			return nil, fmt.Errorf("nil pointer provided")
+		}
+
+		v = v.Elem()
+	}
+
+	if v.Kind() != reflect.Struct {
+		return nil, fmt.Errorf("provided value is %s, expected struct", v.Kind())
+	}
+
+	t := v.Type()
+	fields := make([]DBField, 0, t.NumField())
+
+	for i := range t.NumField() {
+		f := t.Field(i)
+
+		if !f.IsExported() {
+			continue
+		}
+
+		tag := f.Tag.Get("db")
+		if tag == "-" {
+			continue
+		}
+
+		if tag == "" {
+			tag = toSnakeCase(f.Name)
+		}
+
+		if strings.Contains(tag, "omitempty") && reflect.DeepEqual(v.Field(i).Interface(), reflect.Zero(f.Type).Interface()) {
+			continue
+		}
+
+		fields = append(fields, DBField{
+			Name:  tag,
+			Value: v.Field(i).Interface(),
+			Type:  f.Type,
+		})
+	}
+	return fields, nil
+}
+
+func toSnakeCase(s string) string {
+	var res string
+
+	for i, r := range s {
+		if unicode.IsUpper(r) {
+			if i > 0 {
+				res += "_"
+			}
+			res += string(unicode.ToLower(r))
+		} else {
+			res += string(r)
+		}
+	}
+	return res
+}
+
+func (q *Query) InsertStruct(s any, table string) (*Query, error) {
+	fields, err := StructTagsToFields(s)
+	if err != nil {
+		return nil, err
+	}
+
+	columns := make([]string, 0, len(fields))
+	values := make([]any, 0, len(fields))
+
+	for _, f := range fields {
+		columns = append(columns, f.Name)
+		values = append(values, f.Value)
+	}
+
+	if len(columns) == 0 {
+		return nil, fmt.Errorf("no columns to insert")
+	}
+
+	q.Insert(table, columns...).Values(len(columns)).AddArgs(values...)
+	return q, nil
+}