using System;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using SciChart.Core.Extensions;

namespace RecipeEditorLib.RecipeModel.Params
{
    public class RecipeStep : ObservableCollection<Param>
    {

        /// <summary>
        /// 步骤起始编号。
        /// </summary>
        public const int START_INDEX = 1;

        #region Variables

        private bool _isHideValue;

        
        /// <summary>
        /// 当配方步骤的IsSaved属性发生变化时，触发此事件。
        /// </summary>
        public event EventHandler<bool> SavedStateChanged;
        

        #endregion

        #region Constructors

        public RecipeStep(RecipeStep previous)
        {
            Previous = previous;
            IsSaved = true;
        }

        #endregion

        #region Properties
        
        /// <summary>
        /// 父级配方集合。
        /// </summary>
        public RecipeStepCollection Parent { get; internal set; }

        /// <summary>
        /// 返回配方步骤序号参数。
        /// </summary>
        public StepParam StepNoParam => this.FirstOrDefault(x => x is StepParam) as StepParam;

        /// <summary>
        /// 返回步骤序号。
        /// </summary>
        public int? StepNo
        {
            get
            {
                var param = StepNoParam;
                return param?.Value ?? null;
            }
        }

        /// <summary>
        /// 返回步骤执行时长。
        /// </summary>
        public double? StepTime
        {
            get
            {
                var param = this.FirstOrDefault(x => x is DoubleParam && string.Equals(x.Name,
                    RecipColNo.Time.ToString(), StringComparison.CurrentCultureIgnoreCase)) as DoubleParam;
                return param?.Value;
            }
        }

        /// <summary>
        /// 返回当前配方步骤是否已保存。
        /// </summary>
        public bool IsSaved { get; private set;}

        /// <summary>
        /// 返回前序配方。
        /// </summary>
        public RecipeStep Previous { get; private set; }

        /// <summary>
        /// 返回后序配方。
        /// </summary>
        public RecipeStep Next { get; private set;}

        /// <summary>
        /// 返回是否隐藏当前步骤的参数值。
        /// </summary>
        public bool IsHideValue
        {
            get => _isHideValue;
            set
            {
                _isHideValue = value;
                this.ToList().ForEach(x => x.IsHideValue = value);
            }
        }

        #endregion

        #region Methods

        /// <summary>
        /// 当配方中的参数的属性发生变化时，触发此事件。
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void ParamOnPropertyChanged(object sender, PropertyChangedEventArgs e)
        {
            if (!(sender is IParam param)) 
                return;

            if (e.PropertyName == nameof(Param.IsSaved))
            {
                if (param.IsSaved == false)
                {
                    IsSaved = false;
                }
                else
                {
                    IsSaved = this.ToList().FirstOrDefault(x => x.IsSaved == false) == null;
                }
                
                SavedStateChanged?.Invoke(this, IsSaved);
            }
        }

        
        /// <summary>
        /// 将指定的Param链接到前序Param。
        /// </summary>
        /// <param name="param">当前Step中的参数。</param>
        private void LinkWithPreviousParam(IParam param)
        {
            var preParam = Previous?.FirstOrDefault(x => x.Name == param.Name);
            param.Previous = preParam;
            if (preParam != null)
                preParam.Next = param;
        }
        
        /// <summary>
        /// 将指定的Param链接到后序Param。
        /// </summary>
        /// <param name="param">当前Step中的参数。</param>
        private void LinkWithNextParam(IParam param)
        {
            var nextParam = Next?.FirstOrDefault(x => x.Name == param.Name);
            param.Next = nextParam;
            if (nextParam != null)
                nextParam.Previous = param;
        }

        /// <summary>
        /// 校验步骤中的所有参数。
        /// </summary>
        public void Validate()
        {
            this.ToList().ForEach(x=>x.Validate());
        }

        /// <summary>
        /// 取消所有参数的Highlight状态。
        /// </summary>
        public void ResetHighlight()
        {
            this.ToList().ForEach(x => x.ResetHighlight());
        }

        /// <summary>
        /// 保存当前配方步骤。
        /// </summary>
        public void Save()
        {
            this.ToList().ForEach(x=>x.Save());
        }

        /// <summary>
        /// 設置前序步驟。
        /// </summary>
        /// <param name="step"></param>
        public void SetPreviousStep(RecipeStep step)
        {
            Previous = step;
            
            // 调整Step中Param的链接关系
            this.ToList().ForEach(LinkWithPreviousParam);

            if (Previous == null)
                return;

            // 将前序步骤的后序步骤链接到我自己。
            Previous.Next = this;
        }

        public void SetNextStep(RecipeStep step)
        {
            Next = step;
            this.ToList().ForEach(LinkWithNextParam);
        }

        /// <summary>
        /// 检查StepNo是否为有效值。
        /// </summary>
        /// <param name="stepNo"></param>
        /// <param name="validatedStepNo"></param>
        /// <returns></returns>
        public static bool ValidateStepNo(int? stepNo, out int validatedStepNo)
        {
            validatedStepNo = int.MinValue;
            var isValid =  stepNo >= START_INDEX;
            if (isValid)
                validatedStepNo = stepNo.Value;

            return isValid;
        }

        #endregion

        #region Override Methods
        
        protected override void InsertItem(int index, Param item)
        {
            if (item != null)
            {
                item.Parent = this;
                LinkWithPreviousParam(item);
                LinkWithNextParam(item);
                
                item.PropertyChanged += ParamOnPropertyChanged;
            }

            base.InsertItem(index, item);
        }

        protected override void SetItem(int index, Param item)
        {
            throw new NotSupportedException();
        }

        protected override void RemoveItem(int index)
        {
            if (Count > 0)
            {
                if (index >= 0 && index < Count)
                {
                    this[index].PropertyChanged -= ParamOnPropertyChanged;
                }
            }

            // 将前后两个Param链接起来
            var preParam = this[index].Previous;
            var nextParam = this[index].Next;
            if (preParam != null && nextParam != null)
            {
                preParam.Next = nextParam;
                nextParam.Previous = preParam;
            }
            else if (preParam == null && nextParam != null)
            {
                nextParam.Previous = null;
            }
            else if (preParam != null)
            {
                preParam.Next = null;
            }


            IsSaved = false;
            SavedStateChanged?.Invoke(this, true);

            base.RemoveItem(index);
        }

        protected override void ClearItems()
        {
            this.ToList().ForEach(x => x.PropertyChanged -= ParamOnPropertyChanged);

            IsSaved = Count <= 0;
            SavedStateChanged?.Invoke(this, true);

            base.ClearItems();
        }

        public override string ToString()
        {
            return Count > 0 ? (StepNoParam.ToString()??"Recipe Step, Item={Count}" ): "Empty Recipe Step";
        }

        #endregion
    }
}