PS4SaveManager

using System;
using System.IO;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Formatters.Binary;
using UnityEngine;

/// <summary>
/// This game save manager is Technical Requirements Checklist (TRC) compliant for PS4 development.
/// 
/// Instead of writing to disk files directly (ie: StandaloneSaveManager) we instead serialize
/// our data to a string and use Unity's PlayerPrefs API. This solution is not specific to PS4 and could
/// be used in various situations -- it just so happens that Unity's PS4 integration prefers PlayerPrefs usage.
/// </summary>
public class PS4SaveManager : MonoBehaviour, IGameSave {

	/// <summary>
	/// Binary deserialize any generic data object.
	/// </summary>
	/// <typeparam name="T">The class type of the deserialized data.</typeparam>
	/// <param name="filename">The filename of the data to deserialize.</param>
	/// <returns>The deserialized data if it existed, otherwise a default object.</returns>
	public T BinaryDeserialize<T>(string filename) where T : new() {
		T result = new T();

		// Make sure the data exists
		string dataString = PlayerPrefs.GetString(filename, string.Empty);
		if (dataString == string.Empty) {
			return result;
		}

		// Convert the string into a stream
		BinaryFormatter bf = new BinaryFormatter();
		MemoryStream stream = new MemoryStream(Convert.FromBase64String(dataString));

		try {
			// Deserialize the data
			result = (T)bf.Deserialize(stream);
		} catch (SerializationException e) {
			Debug.Log("BinaryDeserialize failed: " + e.Message);
			throw;
		} finally {
			stream.Close();
		}

		return result;
	}

	/// <summary>
	/// Binary serialize any generic data object.
	/// </summary>
	/// <param name="filename">The filename to save this data to.</param>
	/// <param name="data">The data to serialize.</param>
	public void BinarySerialize(string filename, object data) {
		BinaryFormatter bf = new BinaryFormatter();
		MemoryStream stream = new MemoryStream();

		try {
			// Serialize the data
			bf.Serialize(stream, data);

			// Write to player prefs
			string dataString = Convert.ToBase64String(stream.ToArray());
			PlayerPrefs.SetString(filename, dataString);

		} catch (SerializationException e) {
			Debug.Log("BinarySerialize failed: " + e.Message);
		} finally {
			stream.Close();
		}
	}

	/// <summary>
	/// Delete a given file.
	/// </summary>
	/// <param name="filename">The name of the file to delete.</param>
	public void Delete(string filename) {
		PlayerPrefs.SetString(filename, string.Empty);
	}

	/// <summary>
	/// Checks if a given file exists.
	/// </summary>
	/// <param name="filename">The name of the file to check.</param>
	/// <returns>True if the file exists, false otherwise.</returns>
	public bool FileExists(string filename) {
		return PlayerPrefs.GetString(filename, string.Empty) != string.Empty;
	}

	/// <summary>
	/// Gets the full save path, including the filename.
	/// </summary>
	/// <param name="filename"></param>
	/// <returns>The full save path.</returns>
	public string GetPath(string filename) {
		return string.Empty;
	}

	/// <summary>
	/// Persists all changes to the hardware
	/// </summary>
	public void WriteToDisk() {
		PlayerPrefs.Save();
	}
}