From a643fd99f2f338724121e3750e84ff8bcbb3e2b0 Mon Sep 17 00:00:00 2001
From: Sergey Polygalin <sevil89@gmail.com>
Date: Sun, 17 Dec 2023 17:13:33 +0300
Subject: [PATCH] Builder for single query in saving collections

---
 tpl/codegen_bundle.twig | 16 +++++++++++
 tpl/macros_struct.twig  | 59 +++++++++++++++++++++++++++++++++++++++--
 2 files changed, 73 insertions(+), 2 deletions(-)

diff --git a/tpl/codegen_bundle.twig b/tpl/codegen_bundle.twig
index 463145f..f604d43 100644
--- a/tpl/codegen_bundle.twig
+++ b/tpl/codegen_bundle.twig
@@ -35,10 +35,26 @@ var _ = strings.Clone
 {{ enum_macros.enum(u.object) }}
 {% endfor %}
 
+type queryDiffBuilder struct {
+	query     *strings.Builder
+	values    *strings.Builder
+	update    *strings.Builder
+	rawValues []any
+}
+
+func NewQueryDiffBuilder() queryDiffBuilder {
+	return queryDiffBuilder{
+		query:  &strings.Builder{},
+		values: &strings.Builder{},
+		update: &strings.Builder{},
+	}
+}
+
 {% for u in structs %}
 {{ struct_macros.struct(u.object) }}
 {% endfor %}
 
+
 func CreateById(classId uint32) (meta.Struct, error) {
   switch classId {
 	{% for u in structs %}
diff --git a/tpl/macros_struct.twig b/tpl/macros_struct.twig
index 7d3435b..3c06c41 100644
--- a/tpl/macros_struct.twig
+++ b/tpl/macros_struct.twig
@@ -215,11 +215,66 @@ func Save{{ ctx.s.name }}Diff(ctx context.Context, dbe metadb.Execer, rec {{ ctx
 }
 
 func Save{{ ctx.s.name }}CollectionDiff(ctx context.Context, dbe metadb.Execer, recs []{{ ctx.s.name }}) error {
+	byFieldsKey := map[string]queryDiffBuilder{}
 	for _, rec := range recs {
-		if err := Save{{ ctx.s.name }}Diff(ctx, dbe, rec); err != nil {
-			return err
+		if rec.changedFields.Empty() {
+			continue
 		}
+
+		key := rec.changedFields.GetFieldsKey()
+		if _, ok := byFieldsKey[key]; !ok {
+			builder := NewQueryDiffBuilder()
+
+			builder.query.WriteString("INSERT INTO `{{ ctx.table_name }}` ({{ ctx.pkey_column_expr }}")
+			builder.update.WriteString(" ON DUPLICATE KEY UPDATE {{ ctx.pkey_update_expr }}")
+			builder.values.WriteString(" VALUES ")
+
+			{% if ctx.raw_nonpk_fields|length > 0 %}
+			{% for f in ctx.raw_nonpk_fields %}
+			if rec.{{ f|fname }}Changed() {
+				builder.query.WriteString(",`{{ f.name }}`")
+				builder.update.WriteString(",`{{ f.name }}`=VALUES(`{{ f.name }}`)")
+			}
+			{% endfor %}
+			{% endif %}
+
+			byFieldsKey[key] = builder
+		}
+
+		builder := byFieldsKey[key]
+		builder.values.WriteString("({{ ctx.pkey_values_expr }}")
+
+		{% for f in ctx.pkey %}
+		builder.rawValues = append(builder.rawValues, rec.{{ f|fname }})
+		{% endfor %}
+
+		{% if ctx.raw_nonpk_fields|length > 0 %}
+		{% for f in ctx.raw_nonpk_fields %}
+			if rec.{{ f|fname }}Changed() {
+				builder.values.WriteString(",?")
+				builder.rawValues = append(builder.rawValues, rec.{{ f|fname }})
+			}
+		{% endfor %}
+		{% endif %}
+
+		builder.values.WriteRune(')')
+		builder.values.WriteRune(',')
 	}
+
+	for _, builder := range byFieldsKey {
+		var index int = 1
+		if len(builder.rawValues) > 1 {
+			index = 2
+		}
+		queryBuilder := builder.query
+		builder.query.WriteRune(')')
+		queryBuilder.WriteString(builder.values.String()[0 : len(builder.values.String())-index])
+		queryBuilder.WriteString(builder.update.String())
+
+		_, saveErr := dbe.ExecContext(ctx, queryBuilder.String(), builder.rawValues...)
+		return errors.Wrap(saveErr, queryBuilder.String())
+	}
+
 	return nil
 }
 {% endmacro table_save %}