// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System.Collections;
using System.Linq;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Primitives;
 
namespace Microsoft.AspNetCore.Owin;
 
internal sealed class DictionaryStringArrayWrapper : IDictionary<string, string[]>
{
    public readonly IHeaderDictionary Inner;
 
    public DictionaryStringArrayWrapper(IHeaderDictionary inner)
    {
        Inner = inner;
    }
 
    private static KeyValuePair<string, StringValues> Convert(KeyValuePair<string, string[]> item) => new(item.Key, item.Value);
 
    private static KeyValuePair<string, string[]> Convert(KeyValuePair<string, StringValues> item) => new(item.Key, item.Value);
 
    private string[] Convert(StringValues item) => item;
 
    string[] IDictionary<string, string[]>.this[string key]
    {
        get { return ((IDictionary<string, StringValues>)Inner)[key]; }
        set { Inner[key] = value; }
    }
 
    int ICollection<KeyValuePair<string, string[]>>.Count => Inner.Count;
 
    bool ICollection<KeyValuePair<string, string[]>>.IsReadOnly => Inner.IsReadOnly;
 
    ICollection<string> IDictionary<string, string[]>.Keys => Inner.Keys;
 
    ICollection<string[]> IDictionary<string, string[]>.Values => Inner.Values.Select(Convert).ToList();
 
    void ICollection<KeyValuePair<string, string[]>>.Add(KeyValuePair<string, string[]> item) => Inner.Add(Convert(item));
 
    void IDictionary<string, string[]>.Add(string key, string[] value) => Inner.Add(key, value);
 
    void ICollection<KeyValuePair<string, string[]>>.Clear() => Inner.Clear();
 
    bool ICollection<KeyValuePair<string, string[]>>.Contains(KeyValuePair<string, string[]> item) => Inner.Contains(Convert(item));
 
    bool IDictionary<string, string[]>.ContainsKey(string key) => Inner.ContainsKey(key);
 
    void ICollection<KeyValuePair<string, string[]>>.CopyTo(KeyValuePair<string, string[]>[] array, int arrayIndex)
    {
        foreach (var kv in Inner)
        {
            array[arrayIndex++] = Convert(kv);
        }
    }
 
    public ConvertingEnumerator GetEnumerator() => new ConvertingEnumerator(Inner);
 
    IEnumerator<KeyValuePair<string, string[]>> IEnumerable<KeyValuePair<string, string[]>>.GetEnumerator() => new ConvertingEnumerator(Inner);
 
    IEnumerator IEnumerable.GetEnumerator() => new ConvertingEnumerator(Inner);
 
    bool ICollection<KeyValuePair<string, string[]>>.Remove(KeyValuePair<string, string[]> item) => Inner.Remove(Convert(item));
 
    bool IDictionary<string, string[]>.Remove(string key) => Inner.Remove(key);
 
    bool IDictionary<string, string[]>.TryGetValue(string key, out string[] value)
    {
        StringValues temp;
        if (Inner.TryGetValue(key, out temp))
        {
            value = temp;
            return true;
        }
        value = default(StringValues);
        return false;
    }
 
    public struct ConvertingEnumerator : IEnumerator<KeyValuePair<string, string[]>>, IEnumerator
    {
        private IEnumerator<KeyValuePair<string, StringValues>> _inner;
        private KeyValuePair<string, string[]> _current;
 
        internal ConvertingEnumerator(IDictionary<string, StringValues> inner)
        {
            _inner = inner.GetEnumerator();
            _current = default;
        }
 
        public void Dispose()
        {
            _inner?.Dispose();
            _inner = null;
        }
 
        public bool MoveNext()
        {
            if (!_inner.MoveNext())
            {
                _current = default;
                return false;
            }
 
            _current = Convert(_inner.Current);
            return true;
        }
 
        public KeyValuePair<string, string[]> Current => _current;
 
        object IEnumerator.Current => Current;
 
        void IEnumerator.Reset() => throw new NotSupportedException();
    }
}