using System;
using System.IO;
using System.Text;
using UnityEngine;

namespace Ironspore
{
    // Settings have their own version and file; progression and recovery receipts stay in ProfileStore.
    public sealed class SettingsStore
    {
        readonly string path;
        readonly GameSettingsData defaults;
        public GameSettingsData Data { get; private set; }
        public string Error { get; private set; }

        public SettingsStore(string path, GameSettingsData defaults = null)
        {
            this.path = path;
            this.defaults = (defaults ?? new GameSettingsData()).Copy();
            Data = Load(path) ?? Load(path + ".bak") ?? this.defaults.Copy();
        }

        GameSettingsData Load(string file)
        {
            try
            {
                if (!File.Exists(file))
                    return null;
                var data = defaults.Copy();
                JsonUtility.FromJsonOverwrite(File.ReadAllText(file), data);
                return data.version == 1 ? data : null;
            }
            catch (Exception) { return null; }
        }

        public bool Save(GameSettingsData candidate)
        {
            if (candidate == null || candidate.version != 1)
            {
                Error = "Unsupported settings version.";
                return false;
            }
            try
            {
                var snapshot = candidate.Copy();
                Directory.CreateDirectory(Path.GetDirectoryName(Path.GetFullPath(path)));
                string temp = path + ".tmp";
                using (var stream = new FileStream(temp, FileMode.Create, FileAccess.Write, FileShare.None))
                {
                    byte[] bytes = Encoding.UTF8.GetBytes(JsonUtility.ToJson(snapshot, true));
                    stream.Write(bytes, 0, bytes.Length);
                    stream.Flush(true);
                }
                if (File.Exists(path))
                    File.Replace(temp, path, path + ".bak");
                else
                    File.Move(temp, path);
                Data = snapshot;
                Error = null;
                return true;
            }
            catch (Exception ex) { Error = ex.Message; return false; }
        }
    }
}