using System;
using System.Collections;
using System.Collections.Generic;
using LibAC.NBT.API;

namespace LibAC.NBT
{
    public class CompoundTag : Tag, IDictionary<string, Tag>
    {
        private readonly Dictionary<string, Tag> _value = new Dictionary<string, Tag>();

        public CompoundTag() { }

        public override void ReadValue(ByteLayer data)
        {
            _value.Clear();

            while (true)
            {
                Tag tag = Tag.ReadNamedTag(data);
                if (tag.GetType() == 0)
                {
                    return;
                }

                tag.SetParentTagType(TagType.Compound);
                this[tag.GetKey()] = tag;
            }
        }

        public override void WriteValue(ByteLayer data)
        {
            foreach (var tag in _value.Values)
            {
                Tag.WriteNamedTag(tag, data);
            }

            data.WriteByte((byte)TagType.End);
        }

        public void Put(string name, Tag tag)
        {
            _value[name] = tag;
            tag.SetKey(name);
            tag.UpdateParent(this);
        }

        public Tag? Get(string name)
        {
            return ContainsKey(name) ? _value[name] : null;
        }

        public override TagType GetTagType()
        {
            return TagType.Compound;
        }

        public override object GetValue()
        {
            return null;
        }

        public override void SetValue(object val) { }

        public override void PrettyPrint(int indent, bool recurse)
        {
            Console.WriteLine($"{new string('\t', indent)}{Tag.GetCanonicalName(GetTagType())}: [{_value.Count} entries]");
            Console.WriteLine($"{new string('\t', indent)}");
            if (recurse)
            {
                foreach (var tag in _value.Values)
                {
                    tag.PrettyPrint(indent + 1, true);
                }
            }
        }

        public void EndPrettyPrint(int indent)
        {
            Console.WriteLine($"{new string('\t', indent)}");
        }

        public override void WriteStringifiedValue(StringBuilder builder, int indent, bool isList)
        {
            builder.Append($"{(isList ? new string('\t', indent - 1) : "")}{{\n");

            bool firstEntry = true;
            foreach (var tag in _value.Values)
            {
                if (!firstEntry)
                {
                    builder.Append(",\n");
                }
                firstEntry = false;
                Tag.WriteStringifiedNamedTag(tag, builder, indent);
            }

            builder.Append($"\n{new string('\t', indent - 1)}}}");
        }

        public bool TryGetValue(string key, out Tag value)
        {
            return _value.TryGetValue(key, out value);
        }

        public Tag? this[string key]
        {
            get => _value.ContainsKey(key) ? _value[key] : null;
            set
            {
                if (value != null)
                {
                    _value[key] = value;
                    value.UpdateParent(this);
                }
            }
        }

        public void Add(string key, Tag value)
        {
            _value.Add(key, value);
            value.UpdateParent(this);
        }

        public void Add(KeyValuePair<string, Tag> item)
        {
            _value.Add(item.Key, item.Value);
            item.Value.UpdateParent(this);
        }

        public void Clear()
        {
            UnsetParent();
            _value.Clear();
        }

        public bool Contains(KeyValuePair<string, Tag> item)
        {
            return _value.ContainsKey(item.Key);
        }

        public void CopyTo(KeyValuePair<string, Tag>[] array, int arrayIndex)
        {
            throw new NotImplementedException();
        }

        public bool Remove(KeyValuePair<string, Tag> item)
        {
            return _value.Remove(item.Key);
        }

        public void UnsetParent()
        {
            foreach (var entry in _value)
            {
                entry.Value.SetParentTagType(TagType.End);
                entry.Value.UpdateParent(null);
            }
        }

        public bool ContainsKey(string key)
        {
            return _value.ContainsKey(key);
        }

        public bool ContainsValue(Tag value)
        {
            return _value.ContainsValue(value);
        }

        public void ForEach(Action<string, Tag> action)
        {
            foreach (var entry in _value)
            {
                action(entry.Key, entry.Value);
            }
        }

        public int Count => _value.Count;
        public bool IsReadOnly { get; }

        public bool IsEmpty => _value.Count == 0;

        public bool IsNotEmpty => _value.Count > 0;

        public ICollection<string> Keys => _value.Keys;

        public ICollection<Tag> Values => _value.Values;

        public override void ReadStringifiedValue(StringReader reader)
        {
            reader.Expect('{');

            while (reader.Peek() != '}')
            {
                Tag tag = Tag.ReadStringifiedNamedTag(reader);
                Put(tag.GetKey(), tag);

                if (reader.Peek() == ',') reader.Next();
            }

            reader.Expect('}');
        }

        public void AddAll(IDictionary<string, Tag> other)
        {
            foreach (var entry in other)
            {
                _value[entry.Key] = entry.Value;
                entry.Value.UpdateParent(this);
            }
        }

        public bool Remove(string key)
        {
            if (_value.ContainsKey(key))
            {
                _value[key].UpdateParent(null);
                return _value.Remove(key);
            }

            return false;
        }

        public void RemoveWhere(Predicate<KeyValuePair<string, Tag>> predicate)
        {
            var toRemove = new List<string>();
            foreach (var entry in _value)
            {
                if (predicate(entry))
                {
                    toRemove.Add(entry.Key);
                }
            }

            foreach (var key in toRemove)
            {
                _value[key].UpdateParent(null);
                _value.Remove(key);
            }
        }

        public void UpdateAll(Action<string, Tag> update)
        {
            foreach (var entry in _value)
            {
                update(entry.Key, entry.Value);
            }
        }

        public Tag PutIfAbsent(string key, Func<Tag> ifAbsent)
        {
            if (!_value.ContainsKey(key))
            {
                var tag = ifAbsent();
                tag.UpdateParent(this);
                _value[key] = tag;
                return tag;
            }

            return _value[key];
        }

        public void AddEntries(IEnumerable<KeyValuePair<string, Tag>> newEntries)
        {
            foreach (var entry in newEntries)
            {
                _value.Add(entry.Key, entry.Value);
                entry.Value.UpdateParent(this);
            }
        }

        public IEnumerator<KeyValuePair<string, Tag>> GetEnumerator()
        {
            return _value.GetEnumerator();
        }

        IEnumerator IEnumerable.GetEnumerator()
        {
            return _value.GetEnumerator();
        }
    }
}