using System.Collections.Concurrent;

namespace NeonSprawl.Server.Game.Encounters;

/// <summary>Thread-safe in-memory encounter completion flags (NEO-104).</summary>
public sealed class InMemoryEncounterCompletionStore : IEncounterCompletionStore
{
    private readonly ConcurrentDictionary<string, DateTimeOffset> completedAtByKey = new(StringComparer.Ordinal);

    private readonly ConcurrentDictionary<string, object> keyLocks = new(StringComparer.Ordinal);

    /// <inheritdoc />
    public bool IsCompleted(string playerId, string encounterId)
    {
        var key = EncounterProgressIds.MakeProgressKey(playerId, encounterId);
        return key.Length > 0 && completedAtByKey.ContainsKey(key);
    }

    /// <inheritdoc />
    public bool TryMarkCompleted(string playerId, string encounterId, DateTimeOffset completedAt)
    {
        var key = EncounterProgressIds.MakeProgressKey(playerId, encounterId);
        if (key.Length == 0)
        {
            return false;
        }

        lock (keyLocks.GetOrAdd(key, _ => new object()))
        {
            if (completedAtByKey.ContainsKey(key))
            {
                return false;
            }

            completedAtByKey[key] = completedAt;
            return true;
        }
    }

    /// <inheritdoc />
    public bool TryGetCompletedAt(string playerId, string encounterId, out DateTimeOffset completedAt)
    {
        completedAt = default;
        var key = EncounterProgressIds.MakeProgressKey(playerId, encounterId);
        if (key.Length == 0)
        {
            return false;
        }

        lock (keyLocks.GetOrAdd(key, _ => new object()))
        {
            return completedAtByKey.TryGetValue(key, out completedAt);
        }
    }
}