using System;
using Intromat.Interfaces;
using Intromat.Model.Compiler;
using Intromat.Nodes.Code;
using NodeNetwork.Toolkit.ValueNode;
using ReactiveUI;

namespace Intromat.ViewModels.Editors
{
    public abstract class ExpressionEditorBaseViewModel<T, TValue, TModel> : ValueEditorViewModel<ITypedExpression<T>?>, IExpressionEditor where TValue : LiteralValueBase<T>, new() where TModel : LiteralModelBase<T>, new()
    {
        private T _customValue = default!;
        private ERelativeSource _relativeSource;
        private IObservable<T>? _parentValueProvider;
        private IObservable<T>? _inputValueProvider;
        private readonly ObservableAsPropertyHelper<T> _parentValue;
        private readonly ObservableAsPropertyHelper<T> _inputValue;

        protected ExpressionEditorBaseViewModel()
        {
            this.WhenAnyObservable(vm => vm.ParentValueProvider)
                .ToProperty(this, vm => vm.ParentValue, out _parentValue);
            this.WhenAnyObservable(vm => vm.InputValueProvider)
                .ToProperty(this, vm => vm.InputValue, out _inputValue);
            this.WhenAnyValue(vm => vm.ParentValue, vm => vm.InputValue, vm => vm.CustomValue, vm => vm.RelativeSource)
                .Subscribe(v => Value = CreateLiteralValue(v.Item1, v.Item2, v.Item3, v.Item4));
        }

        protected LiteralValueBase<T> CreateLiteralValue(T parentValue, T inputValue, T customValue, ERelativeSource relativeSource)
        {
            return new TValue
            {
                InputValue = inputValue,
                ParentValue = parentValue,
                Value = customValue,
                RelativeSource = relativeSource
            };
        }

        public TModel CreateModel()
        {
            return new()
            {
                RelativeSource = RelativeSource,
                Value = CustomValue
            };
        }

        public void LoadModel(TModel model)
        {
            RelativeSource = model.RelativeSource;
            CustomValue = model.Value;
        }

        public T CustomValue
        {
            get => _customValue;
            set => this.RaiseAndSetIfChanged(ref _customValue, value);
        }

        public ERelativeSource RelativeSource
        {
            get => _relativeSource;
            set => this.RaiseAndSetIfChanged(ref _relativeSource, value);
        }

        public IObservable<T>? ParentValueProvider
        {
            get => _parentValueProvider;
            set => this.RaiseAndSetIfChanged(ref _parentValueProvider, value);
        }

        public T ParentValue => _parentValue.Value;

        public bool HasParentSource => ParentValueProvider != null;

        public IObservable<T>? InputValueProvider
        {
            get => _inputValueProvider;
            set => this.RaiseAndSetIfChanged(ref _inputValueProvider, value);
        }

        public T InputValue => _inputValue.Value;

        public bool HasInputSource => InputValueProvider != null;

        public CodeGenPortViewModel CodeGenPort => (CodeGenPortViewModel)Parent.Port;
    }
}