FileDataService.cs

using System;
using System.IO;
using System.Threading.Tasks;
using Newtonsoft.Json;
using UnityEngine;

// Unity-compatible file-based data service using Newtonsoft.Json
public class FileDataService : IDataService
{
    private readonly string saveDirectory;
    private readonly JsonSerializerSettings jsonSettings;

    public FileDataService(string saveDirectory = "SaveData")
    {
        this.saveDirectory = Path.Combine(Application.persistentDataPath, saveDirectory);
        this.jsonSettings = new JsonSerializerSettings
        {
            Formatting = Formatting.Indented,
            NullValueHandling = NullValueHandling.Ignore,
            DefaultValueHandling = DefaultValueHandling.Include
        };

        // Ensure save directory exists
        if (!Directory.Exists(this.saveDirectory))
        {
            Directory.CreateDirectory(this.saveDirectory);
        }
    }

    public void Save<T>(string fileName, T data)
    {
        var filePath = Path.Combine(saveDirectory, fileName);
        var json = JsonConvert.SerializeObject(data, jsonSettings);
        File.WriteAllText(filePath, json);
    }

    public T Load<T>(string fileName) where T : class
    {
        var filePath = Path.Combine(saveDirectory, fileName);
        
        if (!File.Exists(filePath))
            return null;

        try
        {
            var json = File.ReadAllText(filePath);
            return JsonConvert.DeserializeObject<T>(json, jsonSettings);
        }
        catch (Exception ex)
        {
            Debug.LogError($"Failed to deserialize {fileName}: {ex.Message}");
            return null;
        }
    }

    public async Task SaveAsync<T>(string fileName, T data)
    {
        var filePath = Path.Combine(saveDirectory, fileName);
        var json = JsonConvert.SerializeObject(data, jsonSettings);
        await File.WriteAllTextAsync(filePath, json);
    }

    public async Task<T> LoadAsync<T>(string fileName) where T : class
    {
        var filePath = Path.Combine(saveDirectory, fileName);
        
        if (!File.Exists(filePath))
            return null;

        try
        {
            var json = await File.ReadAllTextAsync(filePath);
            return JsonConvert.DeserializeObject<T>(json, jsonSettings);
        }
        catch (Exception ex)
        {
            Debug.LogError($"Failed to deserialize {fileName}: {ex.Message}");
            return null;
        }
    }

    public string LoadRaw(string fileName)
    {
        var filePath = Path.Combine(saveDirectory, fileName);
        return File.Exists(filePath) ? File.ReadAllText(filePath) : null;
    }

    public bool FileExists(string fileName)
    {
        var filePath = Path.Combine(saveDirectory, fileName);
        return File.Exists(filePath);
    }

    public void DeleteFile(string fileName)
    {
        var filePath = Path.Combine(saveDirectory, fileName);
        if (File.Exists(filePath))
        {
            File.Delete(filePath);
        }
    }
}