Alexander Shabarshov 2a7a24c9e7 Initial contribution
2025-11-03 14:43:26 +00:00

106 lines
2.8 KiB
C#

/*
* dbMango
*
* Copyright 2025 Deutsche Bank AG
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
namespace Rms.Risk.Mango.Language.Ast;
public class AstStageGroupBy : AstStage
{
private List<AstLet> _id = [];
public AstStageGroupBy(IEnumerable<AstLet> id, IEnumerable<AstLet> fields)
{
foreach (var x in fields)
Add(x);
foreach (var x in id)
{
_id.Add(x);
x.Parent = this;
}
}
public void AddId(AstLet field) => _id.Add(field);
public IReadOnlyList<AstLet> Id => _id;
public IReadOnlyList<AstLet> Fields => Children.OfType<AstLet>().ToList();
public override void Append(StringBuilder sb, int indent)
{
sb.AppendLine($"{Spaces(indent)}GROUP BY");
var first = true;
foreach (var field in Id)
{
if ( !first )
sb.AppendLine(",");
else
first = false;
field.Append(sb, indent + 1);
}
sb.AppendLine();
first = true;
foreach (var field in Fields)
{
if ( !first )
sb.AppendLine(",");
else
{
first = false;
sb.AppendLine($"{Spaces(indent+1)}LET");
}
field.Append(sb, indent + 2);
}
if ( !first )
sb.AppendLine();
}
public override JsonNode? AsJson()
{
var body = new JsonObject();
var _id = Id.OfType<AstLetExpression>().ToList();
// _id can be a single field or an expression
if (_id.Count == 1 && string.IsNullOrWhiteSpace(_id[0].Name) )
body.Add("_id", _id[0].Expression.AsJson());
// alternative method for object-style _id
if (body.Count == 0)
{
var idFields = new JsonObject();
foreach (var field in _id)
field.AddToJson(idFields);
body.Add("_id", idFields);
}
var fields = Fields.OfType<AstLetExpression>().ToList();
foreach (var field in fields)
field.AddToJson(body);
var stage = new JsonObject
{
{ "$group", body }
};
return ApplyOptions(stage);
}
}