//-----------------------------------------------------------------------
// -----------------------------------------------------------------------
// file="ExpNodeTempEnumerator"
// Project: StgSharp
// AuthorGroup: Nitload Space
// Copyright (c) Nitload Space. All rights reserved.
//     
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
//     
// -----------------------------------------------------------------------
// -----------------------------------------------------------------------
using Microsoft.CodeAnalysis.CSharp.Syntax;

using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;

namespace StgSharp.Script.Express
{
    public static class ExpNodeNextEnumeratorExtensions
    {

        public static ExpNodeTempEnumerator AsCollectionEnumerator(this ExpSyntaxNode token, bool unpack)
        {
            ExpNodeTempEnumerator enumerator = new ExpNodeTempEnumerator(token, unpack);
            IExpElementSource type = token.EqualityTypeConvert;
            while (enumerator.MoveNext())
            {
                if (enumerator. Current != type) {
                    throw new InvalidCastException();
                }
            }
            return enumerator;
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static ExpNodePresidentEnumerator ToPresidentEnumerator(this ExpSyntaxNode node)
        {
            return new ExpNodePresidentEnumerator(node);
        }

        public static ExpNodePresidentEnumerator TupleToPresidentEnumerator(this ExpSyntaxNode tuple)
        {
            return new ExpNodePresidentEnumerator(tuple.Right);
        }

    }

    public class ExpNodePresidentEnumerator : IEnumerator<ExpSyntaxNode>
    {

        private int _index = -1;
        private List<ExpSyntaxNode> _begin = new List<ExpSyntaxNode>();

        public ExpNodePresidentEnumerator(ExpSyntaxNode token)
        {
            _begin.Add(token);
            ExpSyntaxNode t = token;
            while (!ReferenceEquals(t.Next, token) && t.Next != null)
            {
                t = t.Next;
                _begin.Add(t);
            }
        }

        public ExpSyntaxNode this[int index]
        {
            get
            {
                ArgumentOutOfRangeException.ThrowIfNegative(index);
                ArgumentOutOfRangeException.ThrowIfGreaterThan(index, _begin.Count);
                return _begin[index];
            }
        }

        public ExpSyntaxNode Current => _begin[_index];

        public int Count => _begin.Count;

        public void AssertEnumeratorCount(int count)
        {
            if (_begin.Count != count) {
                throw new InvalidOperationException(
                    $"Enumerator count mismatch. Expected {count}, but got {_begin.Count}.");
            }
        }

        public void AssertEnumeratorCount(int min, int max)
        {
            if (_begin.Count < min || _begin.Count > max) {
                throw new InvalidOperationException(
                    $"Enumerator count mismatch. Expected between {min} and {max}, but got {_begin.Count}.");
            }
        }

        public Span<ExpSyntaxNode> AsSpan()
        {
            return CollectionsMarshal.AsSpan(_begin);
        }

        public void Dispose()
        {
            return;
        }

        public bool MoveNext()
        {
            if (_index < _begin.Count - 1)
            {
                _index++;
                return true;
            }
            return false;
        }

        public void Reset()
        {
            _index = -1;
        }

        object IEnumerator.Current => this.Current;

    }

    public class ExpNodeTempEnumerator : IEnumerator<ExpSyntaxNode>
    {

        private ExpSyntaxNode? _current,_begin;

        public ExpNodeTempEnumerator(ExpSyntaxNode node)
        {
            _current = null;
            _begin = node;
        }

        public ExpNodeTempEnumerator(ExpSyntaxNode node, bool unpack)
        {
            _current = null;
            _begin = unpack ? node.Right : node;
        }

        public ExpSyntaxNode Current => _current!;

        public bool MoveNext()
        {
            if (_current == null)
            {
                _current = _begin;
                return true;
            }
            ExpSyntaxNode next = _current.Next;
            if (ReferenceEquals(next, _begin) || next == null) {
                return false;
            }
            _current = next;
            return true;
        }

        void IDisposable.Dispose()
        {
            return;
        }

        void IEnumerator.Reset()
        {
            _current = null;
        }

        object IEnumerator.Current => _current;

    }
}