#nullable enable
using Barotrauma.Extensions;
using System.Linq;
using System.Collections.Generic;
using System.Collections.Immutable;
using System;

namespace Barotrauma
{
    class AIObjectiveGetItems : AIObjective
    {
        public override Identifier Identifier { get; set; } = "get items".ToIdentifier();
        public override string DebugTag => $"{Identifier}";
        public override bool KeepDivingGearOn => true;
        public override bool AllowMultipleInstances => true;
        protected override bool AllowWhileHandcuffed => false;

        public bool AllowStealing { get; set; }
        public bool TakeWholeStack { get; set; }
        public bool AllowVariants { get; set; }
        public bool Equip { get; set; }
        public bool Wear { get; set; }
        public bool CheckInventory { get; set; }
        public bool EvaluateCombatPriority { get; set; }
        public bool CheckPathForEachItem { get; set; }
        public bool RequireNonEmpty { get; set; }
        public bool RequireAllItems { get; set; }
        public bool RequireDivingSuitAdequate { get; set; }

        /// <summary>
        /// T1 = item to check, T2 = tag we're trying to find a suitable item for
        /// </summary>
        public Func<Item, Identifier, bool>? ItemFilter;

        private readonly ImmutableArray<Identifier> gearTags;
        private readonly ImmutableHashSet<Identifier> ignoredTags;
        private bool subObjectivesCreated;

        public readonly HashSet<Item> achievedItems = new HashSet<Item>();

        public AIObjectiveGetItems(Character character, AIObjectiveManager objectiveManager, IEnumerable<Identifier> identifiersOrTags, float priorityModifier = 1) : base(character, objectiveManager, priorityModifier)
        {
            gearTags = AIObjectiveGetItem.ParseGearTags(identifiersOrTags).ToImmutableArray();
            ignoredTags = AIObjectiveGetItem.ParseIgnoredTags(identifiersOrTags).ToImmutableHashSet();
        }

        protected override bool CheckObjectiveSpecific() => subObjectivesCreated && subObjectives.None();

        protected override void Act(float deltaTime)
        {
            if (subObjectivesCreated) { return; }
            foreach (Identifier tag in gearTags)
            {
                if (subObjectives.Any(so => so is AIObjectiveGetItem getItem && getItem.IdentifiersOrTags.Contains(tag))) { continue; }
                int count = gearTags.Count(t => t == tag);
                AIObjectiveGetItem? getItem = null;
                TryAddSubObjective(ref getItem, () =>
                {
                   var getItem = new AIObjectiveGetItem(character, tag, objectiveManager, Equip, CheckInventory && count <= 1)
                    {
                        AllowVariants = AllowVariants,
                        Wear = Wear,
                        TakeWholeStack = TakeWholeStack,
                        AllowStealing = AllowStealing,
                        ignoredIdentifiersOrTags = ignoredTags,
                        CheckPathForEachItem = CheckPathForEachItem,
                        RequireNonEmpty = RequireNonEmpty,
                        ItemCount = count,
                        SpeakIfFails = RequireAllItems,
                       
                    };
                    if (ItemFilter != null)
                    {
                        getItem.ItemFilter = (Item it) => ItemFilter(it, tag);
                    }
                    return getItem;
                },
                onCompleted: () =>
                {
                    var item = getItem?.TargetItem;
                    if (item?.IsOwnedBy(character) != null)
                    {
                        achievedItems.Add(item);
                    }
                },
                onAbandon: () =>
                {
                    var item = getItem?.TargetItem;
                    if (item != null)
                    {
                        achievedItems.Remove(item);
                    }
                    RemoveSubObjective(ref getItem);
                    if (RequireAllItems)
                    {
                        Abandon = true;
                    }
                });
            }
            subObjectivesCreated = true;
        }

        public override void Reset()
        {
            base.Reset();
            subObjectivesCreated = false;
            achievedItems.Clear();
        }
    }
}