using System.Collections;
using System.Text;

namespace qmonlib.Dependencies.Object.Dynamic
{
    public class DyoMember
    {
         #region *** Constants ***

            public const string PathSeparator = "/";
            public const string PathRoot = ".";
            #endregion

            #region *** Properties ***
            private long Id { get; }
            public ElementType Type { get; }
            private Dyo? Root { get; }
            private DyoMember? Parent { get; }
            public string Name { get; }
            public object? Value { get; private set; }
            public DyoMember[] Members => _members.ToArray();
            #endregion
            #region *** Fields ***
            private static long _idCnt;
            private IList<DyoMember> _members = new List<DyoMember>();
            #endregion

            #region *** Indexer ***
            public DyoMember this[string name] => Get(name);
            public DyoMember this[int ordinal] => _members.Skip(ordinal).First();
            #endregion

            #region *** Constructors ***
            public DyoMember(Dyo? root, ElementType type, DyoMember? parent, string name, object? value = null)
            {
                Id = root?.GetNextId() ?? -1;
                Type = type;
                Parent = parent;
                Root = root;
                Name = name;
                Value = value;
            }
            #endregion

            #region *** Operations ***
            public DyoMember Add(string name, ElementType elementType, object? value = null)
            {
                ThrowIfExists(name);
                var item = new DyoMember(Root ?? (Dyo)this, elementType, this, name, value);
                _members.Add(item);
                return item;
            }

            public void Remove(string name)
            {
                var item = Get(name);
                item.Clear();
                _members.Remove(item);
            }
            public void Clear()
            {
                foreach (var member in _members)
                    member.Clear();
                _members.Clear();
            }

            public DyoMember Get(string name)
            {
                ThrowIfNotExists(name);
                var item = _members.First(x => x.Name == name);
                return item;
            }

            public void Set(string name, object? value)
            {
                var item = Get(name);
                item.Value = value;
            }
            public void Reset()
            {
                foreach (var member in _members)
                    member.Reset();
                Value = null;
            }
            public bool Exists(string name, Dyo.ElementType? elementType = null)
            {
                if (string.IsNullOrEmpty(name)) throw new ArgumentNullException(nameof(name));
                var exists = elementType!=null ? _members.Any(x => x.Name == name && x.Type == elementType) : _members.Any(x => x.Name == name);
                return exists;
            }
            public string GetPath()
            {
                if (Parent == null) return Dyo.PathRoot;
                var path = Parent.GetPath() + Dyo.PathSeparator + Name;
                return path;
            }

            public string Dump()
            {
                var sb = new StringBuilder();
                sb.Append(Name).Append(" [#").Append(Id).Append(";").Append(Type).Append("] ").Append(_members.Count).Append(" members").AppendLine();
                sb.Append("\t").Append("Path:").Append(GetPath()).AppendLine();
                if (Type == ElementType.Value)
                    sb.Append("\t").Append("Value:").Append(Value == null ? "NULL" : Value.ToString()).AppendLine();
                foreach (var member in _members)
                    sb.Append("\t* ").Append(member.Dump());
                return sb.ToString();
            }
            #endregion

            #region *** Private Operations ***

            private void ThrowIfNotExists(string name)
            {
                if (!Exists(name)) throw new Exception($"Dyo member with name '{name}' does not exist.");
            }
            private void ThrowIfExists(string name)
            {
                if (Exists(name)) throw new Exception($"Dyo member with name '{name}' already exists.");
            }
            private long GetNextId()
            {
                _idCnt++;
                return _idCnt;
            }
            #endregion
            #region *** Nested Types ***
            public enum ElementType
            {
                Value,
                Object,
                Collection,
                Root
            }

            #endregion
        }
    
}