/* 
 *                                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 AstStageAddFields : AstStage
{
    public AstStageAddFields(IEnumerable<AstLet> fields)
    {
        foreach (var field in fields)
            Add((AstNodeBase)field);
    }

    public IReadOnlyList<AstLet> Fields => Children.OfType<AstLet>().ToList();

    public override void Append(StringBuilder sb, int indent)
    {
        sb.AppendLine($"{Spaces(indent)}ADD");

        var first = true;
        foreach (var field in Fields)
        {
            if ( !first )
                sb.AppendLine(",");
            else
                first = false;

            if ( field is AstLetExpression let)
            {
                if ( (let.Expression is AstExpressionVariable ev) && string.IsNullOrWhiteSpace(let.Name))
                {
                    sb.Append($"{Spaces(indent + 1)}");
                    ev.Append(sb, indent + 1);
                }
                else
                    let.Append(sb, indent + 1);
            }
            else
                ((AstNodeBase)field).Append(sb, indent + 1);
        }
        sb.AppendLine();
    }

    public override JsonNode? AsJson()
    {

        var fields = new JsonObject();
        
        foreach (var field in Fields)
        {
            field.AddToJson(fields);
        }

        var stage = new JsonObject([ new("$addFields", fields)]);
        return ApplyOptions(stage);
    }
}