using System;
using Godot;
using Godot.Collections;
using FileAccess = Godot.FileAccess;

namespace Babushka.scripts.CSharp.Common.Savegame;

/// <summary>
/// Handles the saving and loading of game states.
/// Holds the central SaveData object that serves as a temporary SaveFile.
/// Automatically writes to disk on every scene change.
/// </summary>
public static class SavegameService
{
    public static readonly string SavePath = "user://babushka_savegame.json";

    public static Dictionary<string, string> SaveDatas = new ();
    
    public static bool _loaded = false;
    

    /// <summary>
    /// Adds or overwrites an entry in the SaveData dictionary.
    /// </summary>
    /// <param name="saveData"></param>
    public static void AppendSave(SaveData saveData)
    {
        string key = string.Concat(saveData.SceneName, "_", saveData.Id);

        if (SaveDatas.TryGetValue(key, out var value))
        {
            SaveDatas[key] = saveData.JsonPayload;
        }
        else
        {
            SaveDatas.Add(key, saveData.JsonPayload);
        }
    }
    
    
    /// <summary>
    /// Checks the SaveData dictionary for an entry and returns the jsondata as a string for it.
    /// Requires the scenename and object ID for lookup.
    /// </summary>
    /// <param name="sceneName"></param>
    /// <param name="id"></param>
    /// <returns></returns>
    public static string GetSaveData(string sceneName, string id)
    {
        string saveData = "";
        
        string key = string.Concat(sceneName, "_", id);
        
        if (!_loaded)
        {
            GD.Print("SavegameService: SaveFile not loaded.");
            return saveData;
        }
        
        if (SaveDatas.ContainsKey(key))
        {
            saveData = SaveDatas[key];
        }

        return saveData;
    }


    /// <summary>
    /// Writes the contents of the current SaveData dictionary to disk as a json file.
    /// </summary>
    public static void Save()
    {
        string json = Json.Stringify(SaveDatas, indent: "\t");
        using var file = FileAccess.Open(SavePath, FileAccess.ModeFlags.Write);
        file.StoreString(json);
    }

    /// <summary>
    /// Loads the current savegame file from disk and parses it into the SaveData dictionary.
    /// </summary>
    public static void Load()
    {
        try
        {
            string saveDataJson = FileAccess.GetFileAsString(SavePath);
            SaveDatas = Json.ParseString(saveDataJson).AsGodotDictionary<string, string>();  
        }
        catch(Exception e)
        {
            GD.PrintRich(e.Message);
            return;
        }

        _loaded = true;
    }

    public static void Reset()
    {
        SaveDatas = new ();
        Save();
    }
}