using System.Collections.Generic;
using GraphQL.Resolvers;
using GraphQL.Types;
using xCommons.Extensions;
using xDataService.Providers;
using xDataService.Interfaces;
using xDataService.Models;
using xModels.Base;

namespace xDataService.GraphQL {
    public abstract class XBaseGraphQLSubscription<TEntity, TKey, TGraph> : ObjectGraphType
    where TGraph : IGraphType
    where TEntity : XBaseEntity<TKey> {
        public XBaseGraphQLSubscription (IXBaseRepositoryEvents<TEntity> eventProvider = null) {
            //
            Name = GetType ().Name;

            //
            // Check if base repository patter registered ...
            if (!eventProvider.IsNull ()) {
                //
                // Add ...
                AddField (new EventStreamFieldType {
                    //
                    Name = nameof (XBaseRepositoryEvents<TEntity>.AddEvent),
                        Type = typeof (XBaseGraphQLEventType<TEntity, TKey, TGraph>),
                        Resolver = new FuncFieldResolver<XBaseEventModel<TEntity>> (
                            context => context.Source as XBaseEventModel<TEntity>
                        ),
                        Subscriber = new EventStreamResolver<XBaseEventModel<TEntity>> (context => {
                            return eventProvider.OnAddObservable;
                        })
                });

                //
                // Add Many ...
                AddField (new EventStreamFieldType {
                    //
                    Name = nameof (XBaseRepositoryEvents<TEntity>.AddManyEvent),
                        Type = typeof (XBaseGraphQLEventType<TEntity, TKey, TGraph>),
                        Resolver = new FuncFieldResolver<XBaseEventModel<IEnumerable<TEntity>>> (
                            context => context.Source as XBaseEventModel<IEnumerable<TEntity>>
                        ),
                        Subscriber = new EventStreamResolver<XBaseEventModel<IEnumerable<TEntity>>> (context => {
                            return eventProvider.OnAddManyObservable;
                        })
                });

                //
                // Update ...
                AddField (new EventStreamFieldType {
                    //
                    Name = nameof (XBaseRepositoryEvents<TEntity>.UpdateEvent),
                        Type = typeof (XBaseGraphQLEventType<TEntity, TKey, TGraph>),
                        Resolver = new FuncFieldResolver<XBaseEventModel<TEntity>> (
                            context => context.Source as XBaseEventModel<TEntity>
                        ),
                        Subscriber = new EventStreamResolver<XBaseEventModel<TEntity>> (context => {
                            return eventProvider.OnUpdateObservable;
                        })
                });

                //
                // Update Mnay ...
                AddField (new EventStreamFieldType {
                    //
                    Name = nameof (XBaseRepositoryEvents<TEntity>.UpdateManyEvent),
                        Type = typeof (XBaseGraphQLEventType<TEntity, TKey, TGraph>),
                        Resolver = new FuncFieldResolver<XBaseEventModel<IEnumerable<TEntity>>> (
                            context => context.Source as XBaseEventModel<IEnumerable<TEntity>>
                        ),
                        Subscriber = new EventStreamResolver<XBaseEventModel<IEnumerable<TEntity>>> (context => {
                            return eventProvider.OnUpdateManyObservable;
                        })
                });

                //
                // Remove ...
                AddField (new EventStreamFieldType {
                    //
                    Name = nameof (XBaseRepositoryEvents<TEntity>.RemoveEvent),
                        Type = typeof (XBaseGraphQLEventType<TEntity, TKey, TGraph>),
                        Resolver = new FuncFieldResolver<XBaseEventModel<TEntity>> (
                            context => context.Source as XBaseEventModel<TEntity>
                        ),
                        Subscriber = new EventStreamResolver<XBaseEventModel<TEntity>> (context => {
                            return eventProvider.OnRemoveObservable;
                        })
                });

                //
                // Remove Many ...
                AddField (new EventStreamFieldType {
                    //
                    Name = nameof (XBaseRepositoryEvents<TEntity>.RemoveManyEvent),
                        Type = typeof (XBaseGraphQLEventType<TEntity, TKey, TGraph>),
                        Resolver = new FuncFieldResolver<XBaseEventModel<IEnumerable<TEntity>>> (
                            context => context.Source as XBaseEventModel<IEnumerable<TEntity>>
                        ),
                        Subscriber = new EventStreamResolver<XBaseEventModel<IEnumerable<TEntity>>> (context => {
                            return eventProvider.OnRemoveManyObservable;
                        })
                });
            }
        }
    }
}