using System;
using System.IO;

using UnityEngine;

using Framework.Services;

namespace Framework.Storage {
  
  /// <summary>Manages the save slots in which game states can be stored</summary>
  [
    ServiceScope(Scope.Global)
  ]
  public class SaveSlotManager : Service, ISaveSlotManager {

    /// <summary>Checks whether the slot with the specified index contains save data</summary>
    /// <param name="slotIndex">Index of the slot that will be checked</param>
    /// <returns>True if the specified save slot is filled</returns>
    public bool IsSlotFilled(int slotIndex) {
      string saveSlotPath = getSaveSlotPath(slotIndex);
      return Directory.Exists(saveSlotPath);
    }

    /// <summary>Deletes the save slot with the specified index</summary>
    /// <param name="slotIndex">Index of the slot that will be deleted</param>
    public void DeleteSaveSlot(int slotIndex) {
      string saveSlotPath = getSaveSlotPath(slotIndex);
      Directory.Delete(saveSlotPath, recursive: true);
    }

    /// <summary>Returns the absolute path of the slot with the specified index</summary>
    /// <param name="slotIndex">Index of the slot whose path will be returned</param>
    /// <param name="create">Whether to create the slot if it doesn't exist yet</param>
    /// <returns>
    ///   The absolute path fo the slot with the specified index or null if the slot
    ///   does not exist and <paramref name="create" /> was set to false.   
    /// </returns>
    public string GetSaveSlotPath(int slotIndex, bool create = false) {
      string saveSlotPath = getSaveSlotPath(slotIndex);
      if(!Directory.Exists(saveSlotPath) && create) {
        Directory.CreateDirectory(saveSlotPath);
      }
      
      return saveSlotPath;
    }

    /// <summary>Returns the absolute path of a save slot</summary>
    /// <param name="slotIndex">Index of the save slot whose absolute path will be returned</param>
    /// <returns>The absolute path of the save slot with the specified index</returns>
    private string getSaveSlotPath(int slotIndex) {
      //Debug.Log(StandardDirectories.SaveGamePath);
      //Debug.Log(getSaveSlotDirectoryName(slotIndex));
      return Path.Combine(
        StandardDirectories.SaveGamePath, getSaveSlotDirectoryName(slotIndex)
      );
    }

    /// <summary>Builds the name of the directory to use for a save slot</summary>
    /// <param name="slotIndex">Index of the slot for which the directory name is built</param>
    /// <returns>The directory name for the save slot with the specified index</returns>
    private string getSaveSlotDirectoryName(int slotIndex) {
      return "SaveSlot." + slotIndex.ToString();
    }

  }

} // namespace Framework.Storage