feat(repositories): add insert_many method generation

lib/sqlx_tools_generator_cli/src/gen_repositories.rs

@@ -80,6 +80,56 @@ fn gen_insert_method(model: &Model) -> TokenStream {
     }
 }
 
+fn gen_insert_many_method(model: &Model) -> TokenStream {
+    let resource_ident = format_ident!("{}", &model.name);
+    let error_msg = format!("Failed to insert many entities of resource {:?}", model.name.clone());
+    let sql_columns = model.fields.iter()
+        .map(|f| f.name.clone())
+        .collect::<Vec<String>>()
+        .join(", ");
+    let base_insert_query = format!(
+        "INSERT INTO {} ({}) VALUES {{}} ON CONFLICT DO NOTHING",
+        model.table_name,
+        sql_columns
+    );
+    let field_names: Vec<proc_macro2::Ident> = model.fields.iter()
+        .map(|f| format_ident!("{}", &f.name))
+        .collect();
+    let fields_count: usize = model.fields.len();
+
+    quote! {
+        pub async fn insert_many(&self, entities: &Vec<#resource_ident>) -> Result<()> {
+            let values_templates: String = (1..(#fields_count*entities.len()+1))
+                .collect::<Vec<usize>>()
+                .chunks(#fields_count)
+                .map(|c| c.to_vec())
+                .map(|x| format!(
+                    "({})",
+                    x.iter()
+                        .map(|i| format!("${}", i))
+                        .collect::<Vec<String>>()
+                        .join(", ")
+                ))
+                .collect::<Vec<String>>()
+                .join(", ");
+            let query_sql = format!(#base_insert_query, values_templates);
+
+            let mut query = sqlx::query(&query_sql);
+            for entity in entities {
+                query = query
+                    #( .bind( &entity.#field_names ) )*;
+            }
+            query
+                .execute(&self.db.0)
+                .await
+                .context(#error_msg)?;
+
+            Ok(())
+        }
+    }
+}
+
+
 fn generate_repository_file(model: &Model) -> Result<SourceNodeContainer> {
     let resource_name = model.name.clone();
 
@@ -91,6 +141,7 @@ fn generate_repository_file(model: &Model) -> Result<SourceNodeContainer> {
     let get_all_method_code = gen_get_all_method(&model);
     let get_by_id_method_code = gen_get_by_id_method(&model);
     let insert_method_code = gen_insert_method(&model);
+    let insert_many_method_code = gen_insert_many_method(&model);
 
     // TODO: add import line
 
@@ -115,6 +166,8 @@ fn generate_repository_file(model: &Model) -> Result<SourceNodeContainer> {
             #get_by_id_method_code
 
             #insert_method_code
+
+            #insert_many_method_code
         }
     };
     // convert TokenStream into rust code as string