using System;
using System.IO;
using System.Text.Json;

namespace Bedtimer
{
    public static class State
    {
        private sealed class Model
        {
            public string? LastLockCycleId { get; set; }
            public DateTime LastLockUtc { get; set; }
        }

        private static string PathJson => System.IO.Path.Combine(Config.Dir, "state.json");
        private static readonly object _gate = new();

        private static Model Load()
        {
            lock (_gate)
            {
                Directory.CreateDirectory(Path.GetDirectoryName(PathJson)!);
                if (!File.Exists(PathJson)) return new Model();
                try { return JsonSerializer.Deserialize<Model>(File.ReadAllText(PathJson)) ?? new Model(); }
                catch { return new Model(); }
            }
        }

        private static void Save(Model m)
        {
            lock (_gate)
            {
                Directory.CreateDirectory(Path.GetDirectoryName(PathJson)!);
                File.WriteAllText(PathJson, JsonSerializer.Serialize(m, new JsonSerializerOptions { WriteIndented = true }));
            }
        }

        public static bool IsLockedForCycle(string cycleId)
        {
            var m = Load();
            return string.Equals(m.LastLockCycleId, cycleId, StringComparison.Ordinal);
        }

        public static void MarkLocked(string cycleId)
        {
            Save(new Model { LastLockCycleId = cycleId, LastLockUtc = DateTime.UtcNow });
        }
    }
}