// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System;
using System.Collections;
using System.Collections.Generic;
using Microsoft.AspNet.Http;

namespace Microsoft.AspNet.Http.Core.Collections
{
    /// <summary>
    /// Accessors for query, forms, etc.
    /// </summary>
    public class ReadableStringCollection : IReadableStringCollection
    {
        /// <summary>
        /// Create a new wrapper
        /// </summary>
        /// <param name="store"></param>
        public ReadableStringCollection([NotNull] IDictionary<string, string[]> store)
        {
            Store = store;
        }

        private IDictionary<string, string[]> Store { get; set; }

        /// <summary>
        /// Gets the number of elements contained in the collection.
        /// </summary>
        public int Count
        {
            get { return Store.Count; }
        }

        /// <summary>
        /// Gets a collection containing the keys.
        /// </summary>
        public ICollection<string> Keys
        {
            get { return Store.Keys; }
        }


        /// <summary>
        /// Get the associated value from the collection.  Multiple values will be merged.
        /// Returns null if the key is not present.
        /// </summary>
        /// <param name="key"></param>
        /// <returns></returns>
        public string this[string key]
        {
            get { return Get(key); }
        }

        /// <summary>
        /// Determines whether the collection contains an element with the specified key.
        /// </summary>
        /// <param name="key"></param>
        /// <returns></returns>
        public bool ContainsKey(string key)
        {
            return Store.ContainsKey(key);
        }

        /// <summary>
        /// Get the associated value from the collection.  Multiple values will be merged.
        /// Returns null if the key is not present.
        /// </summary>
        /// <param name="key"></param>
        /// <returns></returns>
        public string Get(string key)
        {
            return GetJoinedValue(Store, key);
        }

        /// <summary>
        /// Get the associated values from the collection in their original format.
        /// Returns null if the key is not present.
        /// </summary>
        /// <param name="key"></param>
        /// <returns></returns>
        public IList<string> GetValues(string key)
        {
            string[] values;
            Store.TryGetValue(key, out values);
            return values;
        }

        /// <summary>
        /// 
        /// </summary>
        /// <returns></returns>
        public IEnumerator<KeyValuePair<string, string[]>> GetEnumerator()
        {
            return Store.GetEnumerator();
        }

        /// <summary>
        /// 
        /// </summary>
        /// <returns></returns>
        IEnumerator System.Collections.IEnumerable.GetEnumerator()
        {
            return GetEnumerator();
        }

        private static string GetJoinedValue(IDictionary<string, string[]> store, string key)
        {
            string[] values;
            if (store.TryGetValue(key, out values))
            {
                return string.Join(",", values);
            }
            return null;
        }
    }
}