using System.Text.Json;
using Ananta.Server.Configuration;
using Ananta.Server.Protocol.Client4229938;

namespace Ananta.Server.ClientData.Client4229938;

/// <summary>
/// 改装店改装件的落盘（<c>save/vehicles/&lt;pid&gt;.json</c>）。
///
/// <para>为什么需要：donor 最初把购买结果只放在 <c>WorldEntryState</c> 的内存字典里，
/// 服务端一重启买过的件全没了（donor backlog #2 的原话）。买一次就要写一次盘 —— 没有可靠的
/// session-end 钩子，所以走「每次购买后立刻写」。</para>
///
/// <para>开关 <c>gameplay.repairShop.persistTuning</c>（默认 false = 与 donor 默认一致）：
/// 关掉时本类只读不写，行为完全等同 donor 未接 store 时的样子。</para>
///
/// <para>写盘用 tmp + move 的原子替换，避免写一半崩掉留下截断的 json。</para>
/// </summary>
internal static class VehicleTuningStore
{
    private static readonly object Gate = new();
    private static readonly JsonSerializerOptions Options = new() { WriteIndented = true };

    private static string DirectoryPath =>
        PrivateServerConfigStore.ResolveProjectPath(Path.Combine("save", "vehicles"));

    private static string PathFor(ulong pid) => Path.Combine(DirectoryPath, $"{pid}.json");

    /// <summary>把当前会话的改装状态写盘。开关关闭或 world 为空时直接返回。</summary>
    internal static void Save(ulong pid, WorldEntryState? world)
    {
        if (!PrivateServerConfigStore.Current.Gameplay.RepairShop.PersistTuning)
            return;
        if (world is null)
            return;

        List<VehicleDto> vehicles;
        lock (world.SyncRoot)
        {
            var configs = new HashSet<uint>();
            foreach (var key in world.VehiclePartsByConfig.Keys) configs.Add(key);
            foreach (var key in world.VehicleSuitByConfig.Keys) configs.Add(key);

            vehicles = new List<VehicleDto>(configs.Count);
            foreach (var configId in configs)
            {
                var parts = world.VehiclePartsByConfig.TryGetValue(configId, out var list)
                    ? list.Select(p => new PartDto { Type = p.Type, ConfigId = p.ConfigId }).ToList()
                    : [];
                vehicles.Add(new VehicleDto
                {
                    ConfigId = configId,
                    SuitId = world.VehicleSuitByConfig.GetValueOrDefault(configId),
                    Parts = parts,
                });
            }
        }

        try
        {
            lock (Gate)
            {
                var dir = DirectoryPath;
                System.IO.Directory.CreateDirectory(dir);
                var path = PathFor(pid);
                var tmp = path + ".tmp";
                File.WriteAllText(tmp, JsonSerializer.Serialize(new SaveFile { Vehicles = vehicles }, Options));
                File.Move(tmp, path, overwrite: true);
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine($"[REPAIRSHOP] tuning save failed: {ex.Message}");
        }
    }

    /// <summary>进世界时把盘上的改装状态读回内存。开关关闭或文件不存在时什么也不做。</summary>
    internal static void Load(ulong pid, WorldEntryState world)
    {
        if (!PrivateServerConfigStore.Current.Gameplay.RepairShop.PersistTuning)
            return;

        try
        {
            SaveFile? file;
            var path = PathFor(pid);
            lock (Gate)
            {
                if (!File.Exists(path))
                    return;
                file = JsonSerializer.Deserialize<SaveFile>(File.ReadAllText(path));
            }
            if (file?.Vehicles is null)
                return;

            lock (world.SyncRoot)
            {
                foreach (var v in file.Vehicles)
                {
                    if (v.ConfigId == 0)
                        continue;
                    if (v.SuitId != 0)
                        world.VehicleSuitByConfig[v.ConfigId] = v.SuitId;
                    if (v.Parts is { Count: > 0 })
                        world.VehiclePartsByConfig[v.ConfigId] =
                            v.Parts.Where(p => p.ConfigId != 0).Select(p => (p.Type, p.ConfigId)).ToList();
                }
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine($"[REPAIRSHOP] tuning load failed: {ex.Message}");
        }
    }

    private sealed class SaveFile
    {
        public List<VehicleDto> Vehicles { get; set; } = [];
    }

    private sealed class VehicleDto
    {
        public uint ConfigId { get; set; }
        public uint SuitId { get; set; }
        public List<PartDto> Parts { get; set; } = [];
    }

    private sealed class PartDto
    {
        public uint Type { get; set; }
        public uint ConfigId { get; set; }
    }
}