Database.cs

using System;
using System.Collections.Generic;
using System.IO;
using Newtonsoft.Json;
using UnityEngine;

namespace Decal_Loader;

public class Database {
    public static    Database                   instance { get; private set; }
    private readonly string                     configPath;
    private readonly string                     configFile;
    private          Dictionary<string, string> data; // <uri, guid>

    public static void Init(string configPath, string configFile) {
        instance = new(configPath, configFile);
    }

    private Database(string configPath, string configFile) {
        this.configPath = configPath;
        this.configFile = configFile;

        Load();
    }

    private void Load() {
        try {
            if (File.Exists(configFile)) {
                var json = File.ReadAllText(configFile);
                data = JsonConvert.DeserializeObject<Dictionary<string, string>>(json);
            }
        } catch (Exception e) {
            Debug.LogError(e.Message);
        }

        data ??= [];
    }

    public GUID? GetGuidForUri(string uri) {
        uri = SanitizeUrl(uri);

        if (data.TryGetValue(uri, out var value)) return GUID.Parse(value);
        return null;
    }

    /**
     * Removes the config path from the URI if present.
     * Also replaces `\` with `/`.
     *
     * This ensures that any given file should compute to the same URI no matter where the user's app data folder is, or what OS the game is running on.
     */
    private string SanitizeUrl(string uri) {
        return uri.Replace(configPath, "").Replace(@"\", "/");
    }

    public void Add(string uri, GUID guid) {
        uri = SanitizeUrl(uri);

        data[uri] = guid.ToString();

        Save();
    }

    private void Save() {
        try {
            var json = JsonConvert.SerializeObject(data, Formatting.Indented);
            Directory.CreateDirectory(configPath);
            File.WriteAllText(configFile, json);
        } catch (Exception e) {
            Debug.LogError(e.Message);
        }
    }
}