inabox/InABox.Poster.CSV/ICSVPoster.cs

using CsvHelper.Configuration;
using InABox.Core;
using System;
using System.Collections.Generic;
using System.Linq.Expressions;
using System.Text;

namespace InABox.Poster.CSV
{
    public interface ICSVClassMap
    {
        ClassMap ClassMap { get; }
    }

    public interface ICSVClassMap<T> : ICSVClassMap
    {
        new ClassMap<T> ClassMap { get; }

        ClassMap ICSVClassMap.ClassMap => ClassMap;

        void Map(string name, Expression<Func<T, object>> expr);
    }

    public class CSVClassMap<T> : ClassMap<T>, ICSVClassMap<T>
    {
        public ClassMap<T> ClassMap => this;

        public void Map(string name, Expression<Func<T, object>> expr)
        {
            Map(expr).Name(name);
        }
    }

    public interface ICSVExport<TPostable> : IPostResult<TPostable>
        where TPostable : IPostable
    {
        Type Type { get; }

        ICSVClassMap ClassMap { get; }

        IEnumerable<object> Records { get; }
    }

    public interface ICSVExport<TExport, TPostable> : ICSVExport<TPostable>
        where TExport : class
        where TPostable : IPostable
    {
        new Type Type => typeof(TExport);
        new CSVClassMap<TExport> ClassMap { get; }
        new IEnumerable<TExport> Records { get; }

        Type ICSVExport<TPostable>.Type => Type;
        ICSVClassMap ICSVExport<TPostable>.ClassMap => ClassMap;
        IEnumerable<object> ICSVExport<TPostable>.Records => Records;
    }

    public class CSVExport<TExport, TPostable> : ICSVExport<TExport, TPostable>
        where TExport : class
        where TPostable : IPostable
    {
        public CSVClassMap<TExport> ClassMap { get; } = new CSVClassMap<TExport>();

        public IEnumerable<TExport> Records => items.Where(x => x.Item2.PostedStatus == PostedStatus.Posted).Select(x => x.Item1);

        private List<Tuple<TExport, TPostable>> items = new List<Tuple<TExport, TPostable>>();

        private Dictionary<Type, List<IPostableFragment<TPostable>>> fragments = new Dictionary<Type, List<IPostableFragment<TPostable>>>();

        public IEnumerable<TPostable> PostedEntities => items.Select(x => x.Item2);

        public IEnumerable<KeyValuePair<Type, IEnumerable<IPostableFragment<TPostable>>>> Fragments =>
            fragments.Select(x => new KeyValuePair<Type, IEnumerable<IPostableFragment<TPostable>>>(x.Key, x.Value));

        public void DefineMapping(List<Tuple<string, Expression<Func<TExport, object>>>> mappings)
        {
            foreach(var (name, expr) in mappings)
            {
                ClassMap.Map(name, expr);
            }
        }
        public void Map(string name,  Expression<Func<TExport, object>> expr)
        {
            ClassMap.Map(name, expr);
        }

        public void AddSuccess(TExport export, TPostable postable)
        {
            postable.Post();
            items.Add(new(export, postable));
        }
    }

    /// <summary>
    /// Defines an interface for posters that can export to CSV.
    /// </summary>
    /// <typeparam name="TEntity"></typeparam>
    [Caption("CSV")]
    public interface ICSVPoster<TEntity> : IPoster<TEntity, CSVPosterSettings>
        where TEntity : Entity, IPostable, IRemotable, IPersistent, new()
    {
        bool BeforePost(IDataModel<TEntity> model);

        ICSVExport<TEntity> Process(IDataModel<TEntity> model);

        void AfterPost(IDataModel<TEntity> model, IPostResult<TEntity> result);
    }
}