inabox/InABox.Avalonia/DataModels/ShellColumns.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using InABox.Core;

namespace InABox.Avalonia
{
    public class ShellColumn<TEntity>
        where TEntity : Entity
    {
        public int Index { get; }

        public Expression<Func<TEntity, object?>> Expression { get; }

        public string ColumnName { get; }

        public ShellColumn(int index, Expression<Func<TEntity, object?>> expression)
        {
            Index = index;
            Expression = expression;
            ColumnName = CoreUtils.GetFullPropertyName(expression, ".");
        }
    }

    public class ShellColumns<TParent,TEntity> : IShellColumns<TEntity> where TEntity : Entity
    {
        
        private static Dictionary<string, ShellColumn<TEntity>> _columns = new();

        public int IndexOf(string name) => _columns[name].Index;
        
        public string this[string name] => _columns[name].ColumnName;

        public ShellColumns<TParent,TEntity> Map(string property, Expression<Func<TEntity, object?>> expression)
        {
            int iCol = _columns.Keys.Count;
            if(_columns.TryGetValue(property, out var column))
            {
                iCol = column.Index;
            }
            
            _columns[property] = new(iCol, expression);
            return this;
        }

        public string? FindShellProperty(string entityProperty)
        {
            foreach(var (property, column) in _columns)
            {
                if(column.ColumnName == entityProperty)
                {
                    return property;
                }
            }
            return null;
        }

        public Columns<TEntity> Columns
        {
            get
            {
                var columns = new Columns<TEntity>(ColumnTypeFlags.None).Add(_columns.Values.Select(x => x.ColumnName));
                columns.Add(new Columns<TEntity>(ColumnTypeFlags.Required)); // Have to be added after the other columns to preserve column indexing.
                return columns;
            }
        }
        
        public int Count => _columns.Count;

    }
}