#nullable enable

using System.IO;
using Cysharp.Threading.Tasks;
using UnityEngine;

namespace ShrinkDataSaver
{
    public sealed class ShrinkDataSaverRuntimeConfig
    {
        public ShrinkDataSaverSettings? SettingsOverride { get; set; }
        public int CurrentSaveVersion { get; set; } = 1;
        public bool DontDestroyOnLoadDriver { get; set; } = true;
    }

    public static class ShrinkDataSaverRuntime
    {
        public static bool IsInitialized { get; private set; }

        public static void Initialize(ShrinkDataSaverRuntimeConfig? config = null)
        {
            if (IsInitialized)
                return;

            config ??= new ShrinkDataSaverRuntimeConfig();
            var cfg = config.SettingsOverride ?? ShrinkDataSaverSettings.Instance;

            if (config.SettingsOverride)
                ShrinkDataSaverSettings.Instance = config.SettingsOverride;

            if (cfg == null)
                throw new System.InvalidOperationException("ShrinkDataSaverSettings instance is not available.");
            var rootPath = string.IsNullOrEmpty(cfg.customSavePath)
                ? Application.persistentDataPath
                : cfg.customSavePath;

            var savesDir = Path.Combine(rootPath, "saves");
            var settingsPath = Path.Combine(rootPath, cfg.settingsFileName);
            var storage = new LocalStorageProvider(rootPath);

            ShrinkSettings.Initialize(storage, settingsPath);
            ShrinkSave.Initialize(storage, savesDir, cfg.saveFileExtension, config.CurrentSaveVersion);
            ShrinkSettings.LoadAsync().Forget();
            ShrinkDataSaverLifecycleDriver.EnsureCreated(config.DontDestroyOnLoadDriver);
            IsInitialized = true;

            Debug.Log($"[ShrinkDataSaver] Runtime initialized. Root: {rootPath}");
        }

        internal static void ResetForTesting()
        {
            IsInitialized = false;
        }
    }

    [DefaultExecutionOrder(-1999)]
    internal sealed class ShrinkDataSaverLifecycleDriver : MonoBehaviour
    {
        private static ShrinkDataSaverLifecycleDriver? _instance;
        private float _autoSaveTimer;

        public static void EnsureCreated(bool dontDestroyOnLoad)
        {
            if (_instance != null)
                return;

            var go = new GameObject("ShrinkDataSaverRuntimeDriver");
            _instance = go.AddComponent<ShrinkDataSaverLifecycleDriver>();
            if (dontDestroyOnLoad)
                DontDestroyOnLoad(go);
        }

        private void Update()
        {
            var interval = ShrinkSave.GetMinAutoSaveInterval();
            if (interval <= 0f || ShrinkSave.LoadedSlot < 0)
                return;

            _autoSaveTimer += Time.unscaledDeltaTime;
            if (_autoSaveTimer < interval)
                return;

            _autoSaveTimer = 0f;
            ShrinkSave.SaveSlotAsync(ShrinkSave.LoadedSlot).Forget();
        }

        private async void OnApplicationQuit()
        {
            await ShrinkSettings.SaveAsync();
        }

        private async void OnApplicationPause(bool paused)
        {
            if (paused)
                await ShrinkSettings.SaveAsync();
        }
    }
}