using System;
using System.Collections.Generic;

namespace AibisDream.Kit
{
    public interface ISequence : IAction
    {
        ISequence Append(IAction action);
    }

    internal class Sequence : ISequence
    {
        private IAction _currentAction;
        private int _currentActionIndex;
        private readonly List<IAction> _actions = ListPool<IAction>.Get();

        private Sequence()
        {
        }

        private static readonly SimpleObjectPool<Sequence> SimpleObjectPool = new(() => new Sequence(), null, 10);

        public static Sequence Allocate()
        {
            var sequence = SimpleObjectPool.Allocate();
            sequence.ActionID = ActionKit.IDGenerator++;
            sequence.Reset();
            sequence.IsFinalized = false;
            return sequence;
        }

        public bool Paused { get; set; }

        public bool IsFinalized { get; set; }

        public ulong ActionID { get; set; }
        public ActionStatus Status { get; set; }

        public void OnStart()
        {
            if (_actions.Count > 0)
            {
                _currentActionIndex = 0;
                _currentAction = _actions[_currentActionIndex];
                _currentAction.Reset();
                TryExecuteUntilNextNotFinished();
            }
            else
            {
                this.Finish();
            }
        }

        void TryExecuteUntilNextNotFinished()
        {
            while (_currentAction != null && _currentAction.Execute(0))
            {
                _currentActionIndex++;

                if (_currentActionIndex < _actions.Count)
                {
                    _currentAction = _actions[_currentActionIndex];
                    _currentAction.Reset();
                }
                else
                {
                    _currentAction = null;
                    this.Finish();
                }
            }
        }

        public void OnExecute(float dt)
        {
            if (_currentAction != null)
            {
                if (_currentAction.Execute(dt))
                {
                    _currentActionIndex++;

                    if (_currentActionIndex < _actions.Count)
                    {
                        _currentAction = _actions[_currentActionIndex];
                        _currentAction.Reset();

                        TryExecuteUntilNextNotFinished();
                    }
                    else
                    {
                        this.Finish();
                    }
                }
            }
            else
            {
                this.Finish();
            }
        }

        public void OnFinish()
        {
        }

        public ISequence Append(IAction action)
        {
            _actions.Add(action);
            return this;
        }

        public void Deinit()
        {
            if (!IsFinalized)
            {
                IsFinalized = true;

                foreach (var action in _actions)
                {
                    action.Deinit();
                }

                _actions.Clear();

                ActionKitMonoBehaviourEvents.AddCallback(
                    new ActionQueueRecycleCallback<Sequence>(SimpleObjectPool, this));
            }
        }

        public void Reset()
        {
            _currentActionIndex = 0;
            Status = ActionStatus.NotStart;
            Paused = false;
            foreach (var action in _actions)
            {
                action.Reset();
            }
        }
    }

    public static class SequenceExtension
    {
        public static ISequence Sequence(this ISequence self, Action<ISequence> sequenceSetting)
        {
            var repeat = Kit.Sequence.Allocate();
            sequenceSetting(repeat);
            return self.Append(repeat);
        }
    }
}