1 files changed, 134 insertions, 0 deletions
diff --git a/src/StardewModdingAPI/Framework/ModHelper.cs b/src/StardewModdingAPI/Framework/ModHelper.cs
new file mode 100644
index 00000000..2b562b4f
--- /dev/null
+++ b/src/StardewModdingAPI/Framework/ModHelper.cs
@@ -0,0 +1,134 @@
+using System;
+using System.IO;
+using Newtonsoft.Json;
+using StardewModdingAPI.Advanced;
+using StardewModdingAPI.Framework.Reflection;
+
+namespace StardewModdingAPI.Framework
+{
+    /// <summary>Provides simplified APIs for writing mods.</summary>
+    internal class ModHelper : IModHelper
+    {
+        /*********
+        ** Properties
+        *********/
+        /// <summary>The JSON settings to use when serialising and deserialising files.</summary>
+        private readonly JsonSerializerSettings JsonSettings = new JsonSerializerSettings
+        {
+            Formatting = Formatting.Indented,
+            ObjectCreationHandling = ObjectCreationHandling.Replace // avoid issue where default ICollection<T> values are duplicated each time the config is loaded
+        };
+
+
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>The mod directory path.</summary>
+        public string DirectoryPath { get; }
+
+        /// <summary>Simplifies access to private game code.</summary>
+        public IReflectionHelper Reflection { get; } = new ReflectionHelper();
+
+        /// <summary>Metadata about loaded mods.</summary>
+        public IModRegistry ModRegistry { get; }
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="modDirectory">The mod directory path.</param>
+        /// <param name="modRegistry">Metadata about loaded mods.</param>
+        /// <exception cref="ArgumentException">An argument is null or invalid.</exception>
+        /// <exception cref="InvalidOperationException">The <paramref name="modDirectory"/> path does not exist on disk.</exception>
+        public ModHelper(string modDirectory, IModRegistry modRegistry)
+        {
+            // validate
+            if (modRegistry == null)
+                throw new ArgumentException("The mod registry cannot be null.");
+            if (string.IsNullOrWhiteSpace(modDirectory))
+                throw new ArgumentException("The mod directory cannot be empty.");
+            if (!Directory.Exists(modDirectory))
+                throw new InvalidOperationException("The specified mod directory does not exist.");
+
+            // initialise
+            this.DirectoryPath = modDirectory;
+            this.ModRegistry = modRegistry;
+        }
+
+        /****
+        ** Mod config file
+        ****/
+        /// <summary>Read the mod's configuration file (and create it if needed).</summary>
+        /// <typeparam name="TConfig">The config class type. This should be a plain class that has public properties for the settings you want. These can be complex types.</typeparam>
+        public TConfig ReadConfig<TConfig>()
+            where TConfig : class, new()
+        {
+            var config = this.ReadJsonFile<TConfig>("config.json") ?? new TConfig();
+            this.WriteConfig(config); // create file or fill in missing fields
+            return config;
+        }
+
+        /// <summary>Save to the mod's configuration file.</summary>
+        /// <typeparam name="TConfig">The config class type.</typeparam>
+        /// <param name="config">The config settings to save.</param>
+        public void WriteConfig<TConfig>(TConfig config)
+            where TConfig : class, new()
+        {
+            this.WriteJsonFile("config.json", config);
+        }
+
+        /****
+        ** Generic JSON files
+        ****/
+        /// <summary>Read a JSON file.</summary>
+        /// <typeparam name="TModel">The model type.</typeparam>
+        /// <param name="path">The file path relative to the mod directory.</param>
+        /// <returns>Returns the deserialised model, or <c>null</c> if the file doesn't exist or is empty.</returns>
+        public TModel ReadJsonFile<TModel>(string path)
+            where TModel : class
+        {
+            // read file
+            string fullPath = Path.Combine(this.DirectoryPath, path);
+            string json;
+            try
+            {
+                json = File.ReadAllText(fullPath);
+            }
+            catch (Exception ex) when (ex is DirectoryNotFoundException || ex is FileNotFoundException)
+            {
+                return null;
+            }
+
+            // deserialise model
+            TModel model = JsonConvert.DeserializeObject<TModel>(json, this.JsonSettings);
+            if (model is IConfigFile)
+            {
+                var wrapper = (IConfigFile)model;
+                wrapper.ModHelper = this;
+                wrapper.FilePath = path;
+            }
+
+            return model;
+        }
+
+        /// <summary>Save to a JSON file.</summary>
+        /// <typeparam name="TModel">The model type.</typeparam>
+        /// <param name="path">The file path relative to the mod directory.</param>
+        /// <param name="model">The model to save.</param>
+        public void WriteJsonFile<TModel>(string path, TModel model)
+            where TModel : class
+        {
+            path = Path.Combine(this.DirectoryPath, path);
+
+            // create directory if needed
+            string dir = Path.GetDirectoryName(path);
+            if (!Directory.Exists(dir))
+                Directory.CreateDirectory(dir);
+
+            // write file
+            string json = JsonConvert.SerializeObject(model, this.JsonSettings);
+            File.WriteAllText(path, json);
+        }
+    }
+}