using System;

using System.Collections.Generic;

using System.Threading.Tasks;

using Newtonsoft.Json;

using System.Linq;

public class Program

{

    public static async Task Main()

    {

        var data = await GetPanelOfProject();

        var dataStr = JsonConvert.SerializeObject(data);

        Console.WriteLine(dataStr);

    }

    public static List<SurfacePanelDto> QueryData(){

        List<SurfacePanelDto> panelData = new List<SurfacePanelDto>();

        // Parent 1 hierarchy

        var parentId1 = Guid.NewGuid();

        panelData.Add(new SurfacePanelDto { Id = parentId1, Name = "parent 1", OriginId = null, Quantity = 1 });

​

        var parentId11 = Guid.NewGuid();

        panelData.Add(new SurfacePanelDto { Id = parentId11, Name = "parent 11", OriginId = parentId1, Quantity = 1 });

​

        var parentId111 = Guid.NewGuid();

        panelData.Add(new SurfacePanelDto { Id = parentId111, Name = "parent 111", OriginId = parentId11, Quantity = 7 });

​

        var parentId12 = Guid.NewGuid();

        panelData.Add(new SurfacePanelDto { Id = parentId12, Name = "parent 12", OriginId = parentId1, Quantity = 1 });

​

        // Parent 2 hierarchy

        var parentId2 = Guid.NewGuid();

        panelData.Add(new SurfacePanelDto { Id = parentId2, Name = "parent 2", OriginId = null, Quantity = 1 });

​

        var parentId21 = Guid.NewGuid();

        panelData.Add(new SurfacePanelDto { Id = parentId21, Name = "parent 21", OriginId = parentId2, Quantity = 1 });

​

        var parentId211 = Guid.NewGuid();

        panelData.Add(new SurfacePanelDto { Id = parentId211, Name = "parent 211", OriginId = parentId21, Quantity = 5 });

​

        var parentId22 = Guid.NewGuid();

        panelData.Add(new SurfacePanelDto { Id = parentId22, Name = "parent 22", OriginId = parentId2, Quantity = 2 });

        return panelData;

    }

    public static async Task<List<SurfacePanelDto>> GetPanelOfProject()

    {

        List<SurfacePanelDto> panels = new();

        try

        {

            List<SurfacePanelDto> panelData = QueryData();

​

            // Build hierarchy

            var rootPanels = panelData.Where(d => d.OriginId is null).ToList();

            foreach (var panel in rootPanels)

            {

                panels.Add(GetPanelAndChildren(panelData, panel));

            }

        }

        catch (Exception ex)

        {

            Console.WriteLine($"Error: {ex.Message}");

        }

        return panels;

    }

​

    private static SurfacePanelDto GetPanelAndChildren(List<SurfacePanelDto> panelData, SurfacePanelDto panel)

    {

        panel.Children = panelData.Where(d => d.OriginId == panel.Id).ToList();

        foreach (var child in panel.Children)

        {

            GetPanelAndChildren(panelData, child); // Correct recursion

        }

        // Sum the total quantity including all descendants

        if (panel.Children.Any())

        {

            panel.Quantity = panel.Children.Sum(c => c.Quantity);

        }

        return panel;

    }

}

​

public class SurfacePanelDto

{

    public Guid Id { get; set; }

    public string Name { get; set; }

    public string Description { get; set; }

    public int? Quantity { get; set; }

    public Guid? OriginId { get; set; }

​

    public List<SurfacePanelDto> Children { get; set; } = new();

}