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

namespace game.PlayerDataStorage
{
    public enum PlayerKVLocalReadError { None, StaleOrClosing, NotReady }

    /// <summary>A detached snapshot. Failed reads have no data, never a pretend empty save.</summary>
    public sealed class PlayerKVLocalReadResult
    {
        public bool Success => Error == PlayerKVLocalReadError.None;
        public PlayerKVLocalReadError Error { get; }
        public string OwnerInstanceId { get; }
        public string PlayerId { get; }
        public long Epoch { get; }
        public IReadOnlyDictionary<string, string> Data { get; }

        internal PlayerKVLocalReadResult(PlayerKVLocalReadError error, string ownerId,
            string playerId, long epoch, IReadOnlyDictionary<string, string> data = null)
        {
            Error = error; OwnerInstanceId = ownerId; PlayerId = playerId; Epoch = epoch;
            if (error != PlayerKVLocalReadError.None) return;
            if (data == null) throw new ArgumentNullException(nameof(data));
            var copy = new Dictionary<string, string>(StringComparer.Ordinal);
            foreach (var item in data) copy.Add(item.Key, item.Value);
            Data = new ReadOnlyDictionary<string, string>(copy);
        }
    }
}