using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;

namespace game.PlayerDataStorage
{
    // Only two approved in-memory normalizations. Never a persistence receipt or retry queue.
    internal sealed class PlayerKVInitializationIntents
    {
        readonly Dictionary<string,string> values=new Dictionary<string,string>(StringComparer.Ordinal);
        readonly string channel;
        internal long Epoch { get; }
        internal bool Discarded { get; private set; }
        internal int DiscardedCount { get; private set; }
        internal int Count => values.Count;
        internal IReadOnlyDictionary<string,string> Snapshot => new ReadOnlyDictionary<string,string>(new Dictionary<string,string>(values));
        internal PlayerKVInitializationIntents(long epoch,PlayerKVIdentityChannel channel)
        {
            if(!Enum.IsDefined(typeof(PlayerKVIdentityChannel),channel)) throw new ArgumentException("Unknown intent channel.");
            Epoch=epoch; this.channel=channel==PlayerKVIdentityChannel.hwGuest || channel==PlayerKVIdentityChannel.none ? null : channel.ToString();
        }
        internal void Add(long epoch,string key,string value)
        {
            if(Discarded || epoch!=Epoch || key==null || (key!="MMTest" && key!=channel) || value==null)
                throw new InvalidOperationException("Initialization intent rejected.");
            values[key]=value;
        }
        internal void Discard() { if(Discarded) return; DiscardedCount=values.Count; values.Clear(); Discarded=true; }
    }
}