using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Collections.Specialized;
using Avalonia;
using Avalonia.Input.Platform;
using DesertPaintCodex.Models;
using DesertPaintCodex.Services;
using DynamicData;
using DynamicData.Binding;
using ReactiveUI;

namespace DesertPaintCodex.ViewModels
{
    public class SimulatorViewModel : ViewModelBase
    {
        private PaintColor? _paintColor;
        public PaintColor? PaintColor
        {
            get => _paintColor;
            set => this.RaiseAndSetIfChanged(ref _paintColor, value);
        }

        private bool _hasMissingReactions;
        public bool HasMissingReactions
        {
            get => _hasMissingReactions;
            set => this.RaiseAndSetIfChanged(ref _hasMissingReactions, value);
        }

        private bool _isGoodRecipe;

        public bool IsGoodRecipe
        {
            get => _isGoodRecipe;
            set => this.RaiseAndSetIfChanged(ref _isGoodRecipe, value);
        }
        
        public ObservableCollection<Reagent> Reagents { get; } = new();
        public ObservableCollection<Reagent> ActiveReagents { get; } = new();
        public ObservableCollection<RecipeItem> RecipeItems { get; } = new();

        
        private readonly PaintRecipe _currentRecipe = new();

        public SimulatorViewModel()
        {
            List<string> reagentNames = ReagentService.Names;
            for (int i = 0; i < reagentNames.Count; i++)
            {
                Reagents.Add(ReagentService.GetReagent(reagentNames[i]));
            }

            ActiveReagents.CollectionChanged += OnActiveReagentsChanged;

            RecipeItems
                .ToObservableChangeSet()
                .AutoRefresh(item => item.Quantity)
                .Subscribe(_ => Refresh());
        }

        public async void CopyToClipboard()
        {
            IClipboard clipboard = Application.Current.Clipboard;
            await clipboard.SetTextAsync(_currentRecipe.ToString());
        }

        public void MoveItemUp(RecipeItem item)
        {
            int pos = RecipeItems.IndexOf(item);
            if (pos <= 0) return;

            RecipeItems.RemoveAt(pos);
            RecipeItems.Insert(pos - 1, item);

            Refresh();
        }

        public void MoveItemDown(RecipeItem item)
        {
            int pos = RecipeItems.IndexOf(item);
            if ((pos < 0) || (pos >= RecipeItems.Count - 1)) return;

            RecipeItems.RemoveAt(pos);
            RecipeItems.Insert(pos + 1, item);

            Refresh();
        }
        
        private void UpdateRecipe()
        {
            _currentRecipe.Clear();
            foreach (RecipeItem entry in RecipeItems)
            {
                if (!entry.Unused)
                {
                    _currentRecipe.AddReagent(entry.Reagent.Name, entry.Quantity);
                }
            }

            PaintColor = null; // TODO: Find a better way to kick the paint swatch when reassigning color from the same ref.
            PaintColor          = _currentRecipe.ReactedColor;
            HasMissingReactions = _currentRecipe.HasMissingReactions();
            IsGoodRecipe        = !HasMissingReactions && _currentRecipe.IsValidForConcentration(10);
        }

        private void OnActiveReagentsChanged(object? sender, NotifyCollectionChangedEventArgs e)
        {
            HashSet<Reagent> unmatchedReagents = new(ActiveReagents);
            
            for (int i = RecipeItems.Count - 1; i >= 0; i--)
            {
                bool found = false;
                foreach (Reagent reagent in ActiveReagents)
                {
                    if (reagent == RecipeItems[i].Reagent)
                    {
                        unmatchedReagents.Remove(reagent);
                        found = true;
                        break;
                    }
                }

                if (!found) RecipeItems.RemoveAt(i);
            }

            foreach (Reagent reagent in unmatchedReagents)
            {
                RecipeItems.Add(new RecipeItem(reagent, 1));
            }

            Refresh();
        }

        private void Refresh()
        {
            UpdateFlags();
            UpdateRecipe();
        }

        private void UpdateFlags()
        {
            int activeIngredients = 0;
            for (int i = 0; i < RecipeItems.Count; i++)
            {
                RecipeItem item = RecipeItems[i];
                item.First = i == 0;
                item.Last = i == RecipeItems.Count - 1;
                if (item.Quantity > 0)
                {
                    activeIngredients++;
                }
                item.Unused = ((activeIngredients > 5) && item.Reagent.IsCatalyst) || (item.Quantity == 0);
            }
        }
    }
}