using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Diagnostics.Contracts;
using System.Linq;

namespace PleaseIgnore.IntelMap {
    /// <summary>
    ///     Specialization of <see cref="System.ComponentModel.ComponentCollection"/>
    ///     providing a list of <see cref="IntelChannel"/>.
    /// </summary>
    public class IntelChannelCollection : ReadOnlyCollection<IntelChannel> {
        /// <summary>
        ///     Initializes a new instance of <see cref="IntelChannelCollection"/>.
        /// </summary>
        /// <param name="list">
        ///     The list to expose to the user.
        /// </param>
        /// <remarks>
        ///     <paramref name="list"/> is not copied by
        ///     <see cref="IntelChannelCollection(IList{IntelChannel})"/>, so
        ///     a synchronized copy must be made by the container.
        /// </remarks>
        public IntelChannelCollection(IList<IntelChannel> list)
                : base(list) {
            Contract.Requires<ArgumentNullException>(list != null, "list");
            Contract.Requires<ArgumentException>(Contract.ForAll(list, x => x != null));
        }

        /// <summary>
        ///     Gets any <see cref="IntelChannel"/> monitoring the specified
        ///     channel.
        /// </summary>
        /// <param name="name">
        ///     The <see cref="IntelChannel.Name"/> to fetch.
        /// </param>
        /// <returns>
        ///     An instance of <see cref="IntelChannel"/> with the
        ///     <see cref="IntelChannel.Name"/> specified by
        ///     <paramref name="name"/> or <see langword="null"/> if
        ///     no such channel is being monitored.
        /// </returns>
        public IntelChannel this[string name] {
            get {
                if (name == null) {
                    return null;
                } else {
                    return this.FirstOrDefault(x => String.Equals(
                        x.Name,
                        name,
                        StringComparison.OrdinalIgnoreCase));
                }
            }
        }
    }
}