add dictionary/image content helpers for more intuitive usage (#173)

4 files changed, 251 insertions, 0 deletions

diff --git a/src/StardewModdingAPI/Framework/Content/ContentEventBaseHelper.cs b/src/StardewModdingAPI/Framework/Content/ContentEventBaseHelper.cs
new file mode 100644
index 00000000..736cdc70
--- /dev/null
+++ b/src/StardewModdingAPI/Framework/Content/ContentEventBaseHelper.cs
@@ -0,0 +1,98 @@
+using System;
+using System.Collections.Generic;
+using Microsoft.Xna.Framework.Graphics;
+
+namespace StardewModdingAPI.Framework.Content
+{
+    /// <summary>Base implementation for a content helper which encapsulates access and changes to content being read from a data file.</summary>
+    /// <typeparam name="TValue">The interface value type.</typeparam>
+    internal class ContentEventBaseHelper<TValue> : EventArgs
+    {
+        /*********
+        ** Properties
+        *********/
+        /// <summary>Normalises an asset key to match the cache key.</summary>
+        protected readonly Func<string, string> GetNormalisedPath;
+
+
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>The content's locale code, if the content is localised.</summary>
+        public string Locale { get; }
+
+        /// <summary>The normalised asset name being read. The format may change between platforms; see <see cref="IsAssetName"/> to compare with a known path.</summary>
+        public string AssetName { get; }
+
+        /// <summary>The content data being read.</summary>
+        public TValue Data { get; protected set; }
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="locale">The content's locale code, if the content is localised.</param>
+        /// <param name="assetName">The normalised asset name being read.</param>
+        /// <param name="data">The content data being read.</param>
+        /// <param name="getNormalisedPath">Normalises an asset key to match the cache key.</param>
+        public ContentEventBaseHelper(string locale, string assetName, TValue data, Func<string, string> getNormalisedPath)
+        {
+            this.Locale = locale;
+            this.AssetName = assetName;
+            this.Data = data;
+            this.GetNormalisedPath = getNormalisedPath;
+        }
+
+        /// <summary>Get whether the asset name being loaded matches a given name after normalisation.</summary>
+        /// <param name="path">The expected asset path, relative to the game's content folder and without the .xnb extension or locale suffix (like 'Data\ObjectInformation').</param>
+        public bool IsAssetName(string path)
+        {
+            path = this.GetNormalisedPath(path);
+            return this.AssetName.Equals(path, StringComparison.InvariantCultureIgnoreCase);
+        }
+
+        /// <summary>Replace the entire content value with the given value. This is generally not recommended, since it may break compatibility with other mods or different versions of the game.</summary>
+        /// <param name="value">The new content value.</param>
+        /// <exception cref="ArgumentNullException">The <paramref name="value"/> is null.</exception>
+        /// <exception cref="InvalidCastException">The <paramref name="value"/>'s type is not compatible with the loaded asset's type.</exception>
+        public void ReplaceWith(TValue value)
+        {
+            if (value == null)
+                throw new ArgumentNullException(nameof(value), "Can't set a loaded asset to a null value.");
+            if (!this.Data.GetType().IsInstanceOfType(value))
+                throw new InvalidCastException($"Can't replace loaded asset of type {this.GetFriendlyTypeName(this.Data.GetType())} with value of type {this.GetFriendlyTypeName(value.GetType())}. The new type must be compatible to prevent game errors.");
+
+            this.Data = value;
+        }
+
+
+        /*********
+        ** Protected methods
+        *********/
+        /// <summary>Get a human-readable type name.</summary>
+        /// <param name="type">The type to name.</param>
+        protected string GetFriendlyTypeName(Type type)
+        {
+            // dictionary
+            if (type.IsGenericType && type.GetGenericTypeDefinition() == typeof(Dictionary<,>))
+            {
+                Type[] genericArgs = type.GetGenericArguments();
+                return $"Dictionary<{this.GetFriendlyTypeName(genericArgs[0])}, {this.GetFriendlyTypeName(genericArgs[1])}>";
+            }
+
+            // texture
+            if (type == typeof(Texture2D))
+                return type.Name;
+
+            // native type
+            if (type == typeof(int))
+                return "int";
+            if (type == typeof(string))
+                return "string";
+
+            // default
+            return type.FullName;
+        }
+    }
+}
diff --git a/src/StardewModdingAPI/Framework/Content/ContentEventHelper.cs b/src/StardewModdingAPI/Framework/Content/ContentEventHelper.cs
new file mode 100644
index 00000000..26292cab
--- /dev/null
+++ b/src/StardewModdingAPI/Framework/Content/ContentEventHelper.cs
@@ -0,0 +1,47 @@
+using System;
+using System.Collections.Generic;
+using Microsoft.Xna.Framework.Graphics;
+
+namespace StardewModdingAPI.Framework.Content
+{
+    /// <summary>Encapsulates access and changes to content being read from a data file.</summary>
+    internal class ContentEventHelper : ContentEventBaseHelper<object>, IContentEventHelper
+    {
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="locale">The content's locale code, if the content is localised.</param>
+        /// <param name="assetName">The normalised asset name being read.</param>
+        /// <param name="data">The content data being read.</param>
+        /// <param name="getNormalisedPath">Normalises an asset key to match the cache key.</param>
+        public ContentEventHelper(string locale, string assetName, object data, Func<string, string> getNormalisedPath)
+            : base(locale, assetName, data, getNormalisedPath) { }
+
+        /// <summary>Get a helper to manipulate the data as a dictionary.</summary>
+        /// <typeparam name="TKey">The expected dictionary key.</typeparam>
+        /// <typeparam name="TValue">The expected dictionary balue.</typeparam>
+        /// <exception cref="InvalidOperationException">The content being read isn't a dictionary.</exception>
+        public IContentEventHelperForDictionary<TKey, TValue> AsDictionary<TKey, TValue>()
+        {
+            return new ContentEventHelperForDictionary<TKey, TValue>(this.Locale, this.AssetName, this.GetData<IDictionary<TKey, TValue>>(), this.GetNormalisedPath);
+        }
+
+        /// <summary>Get a helper to manipulate the data as an image.</summary>
+        /// <exception cref="InvalidOperationException">The content being read isn't an image.</exception>
+        public IContentEventHelperForImage AsImage()
+        {
+            return new ContentEventHelperForImage(this.Locale, this.AssetName, this.GetData<Texture2D>(), this.GetNormalisedPath);
+        }
+
+        /// <summary>Get the data as a given type.</summary>
+        /// <typeparam name="TData">The expected data type.</typeparam>
+        /// <exception cref="InvalidCastException">The data can't be converted to <typeparamref name="TData"/>.</exception>
+        public TData GetData<TData>()
+        {
+            if (!(this.Data is TData))
+                throw new InvalidCastException($"The content data of type {this.Data.GetType().FullName} can't be converted to the requested {typeof(TData).FullName}.");
+            return (TData)this.Data;
+        }
+    }
+}
diff --git a/src/StardewModdingAPI/Framework/Content/ContentEventHelperForDictionary.cs b/src/StardewModdingAPI/Framework/Content/ContentEventHelperForDictionary.cs
new file mode 100644
index 00000000..8fcaae3c
--- /dev/null
+++ b/src/StardewModdingAPI/Framework/Content/ContentEventHelperForDictionary.cs
@@ -0,0 +1,36 @@
+using System;
+using System.Collections.Generic;
+
+namespace StardewModdingAPI.Framework.Content
+{
+    /// <summary>Encapsulates access and changes to dictionary content being read from a data file.</summary>
+    internal class ContentEventHelperForDictionary<TKey, TValue> : ContentEventBaseHelper<IDictionary<TKey, TValue>>, IContentEventHelperForDictionary<TKey, TValue>
+    {
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="locale">The content's locale code, if the content is localised.</param>
+        /// <param name="assetName">The normalised asset name being read.</param>
+        /// <param name="data">The content data being read.</param>
+        /// <param name="getNormalisedPath">Normalises an asset key to match the cache key.</param>
+        public ContentEventHelperForDictionary(string locale, string assetName, IDictionary<TKey, TValue> data, Func<string, string> getNormalisedPath)
+            : base(locale, assetName, data, getNormalisedPath) { }
+
+        /// <summary>Add or replace an entry in the dictionary data.</summary>
+        /// <param name="key">The entry key.</param>
+        /// <param name="value">The entry value.</param>
+        public void SetEntry(TKey key, TValue value)
+        {
+            this.Data[key] = value;
+        }
+
+        /// <summary>Add or replace an entry in the dictionary data.</summary>
+        /// <param name="key">The entry key.</param>
+        /// <param name="value">A callback which accepts the current value and returns the new value.</param>
+        public void SetEntry(TKey key, Func<TValue, TValue> value)
+        {
+            this.Data[key] = value(this.Data[key]);
+        }
+    }
+}
diff --git a/src/StardewModdingAPI/Framework/Content/ContentEventHelperForImage.cs b/src/StardewModdingAPI/Framework/Content/ContentEventHelperForImage.cs
new file mode 100644
index 00000000..23760f0f
--- /dev/null
+++ b/src/StardewModdingAPI/Framework/Content/ContentEventHelperForImage.cs
@@ -0,0 +1,70 @@
+using System;
+using Microsoft.Xna.Framework;
+using Microsoft.Xna.Framework.Graphics;
+
+namespace StardewModdingAPI.Framework.Content
+{
+    /// <summary>Encapsulates access and changes to dictionary content being read from a data file.</summary>
+    internal class ContentEventHelperForImage : ContentEventBaseHelper<Texture2D>, IContentEventHelperForImage
+    {
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="locale">The content's locale code, if the content is localised.</param>
+        /// <param name="assetName">The normalised asset name being read.</param>
+        /// <param name="data">The content data being read.</param>
+        /// <param name="getNormalisedPath">Normalises an asset key to match the cache key.</param>
+        public ContentEventHelperForImage(string locale, string assetName, Texture2D data, Func<string, string> getNormalisedPath)
+            : base(locale, assetName, data, getNormalisedPath) { }
+
+        /// <summary>Overwrite part of the image.</summary>
+        /// <param name="source">The image to patch into the content.</param>
+        /// <param name="sourceArea">The part of the <paramref name="source"/> to copy (or <c>null</c> to take the whole texture). This must be within the bounds of the <paramref name="source"/> texture.</param>
+        /// <param name="targetArea">The part of the content to patch (or <c>null</c> to patch the whole texture). The original content within this area will be erased. This must be within the bounds of the existing spritesheet.</param>
+        /// <param name="patchMode">Indicates how an image should be patched.</param>
+        /// <exception cref="ArgumentNullException">One of the arguments is null.</exception>
+        /// <exception cref="ArgumentOutOfRangeException">The <paramref name="targetArea"/> is outside the bounds of the spritesheet.</exception>
+        public void PatchImage(Texture2D source, Rectangle? sourceArea = null, Rectangle? targetArea = null, PatchMode patchMode = PatchMode.Replace)
+        {
+            // get texture
+            Texture2D target = this.Data;
+
+            // get areas
+            sourceArea = sourceArea ?? new Rectangle(0, 0, source.Width, source.Height);
+            targetArea = targetArea ?? new Rectangle(0, 0, Math.Min(sourceArea.Value.Width, target.Width), Math.Min(sourceArea.Value.Height, target.Height));
+
+            // validate
+            if (source == null)
+                throw new ArgumentNullException(nameof(source), "Can't patch from a null source texture.");
+            if (sourceArea.Value.X < 0 || sourceArea.Value.Y < 0 || sourceArea.Value.Right > source.Width || sourceArea.Value.Bottom > source.Height)
+                throw new ArgumentOutOfRangeException(nameof(sourceArea), "The source area is outside the bounds of the source texture.");
+            if (targetArea.Value.X < 0 || targetArea.Value.Y < 0 || targetArea.Value.Right > target.Width || targetArea.Value.Bottom > target.Height)
+                throw new ArgumentOutOfRangeException(nameof(targetArea), "The target area is outside the bounds of the target texture.");
+            if (sourceArea.Value.Width != targetArea.Value.Width || sourceArea.Value.Height != targetArea.Value.Height)
+                throw new InvalidOperationException("The source and target areas must be the same size.");
+
+            // get source data
+            int pixelCount = sourceArea.Value.Width * sourceArea.Value.Height;
+            Color[] sourceData = new Color[pixelCount];
+            source.GetData(0, sourceArea, sourceData, 0, pixelCount);
+
+            // merge data in overlay mode
+            if (patchMode == PatchMode.Overlay)
+            {
+                Color[] newData = new Color[targetArea.Value.Width * targetArea.Value.Height];
+                target.GetData(0, targetArea, newData, 0, newData.Length);
+                for (int i = 0; i < sourceData.Length; i++)
+                {
+                    Color pixel = sourceData[i];
+                    if (pixel.A != 0) // not transparent
+                        newData[i] = pixel;
+                }
+                sourceData = newData;
+            }
+
+            // patch target texture
+            target.SetData(0, targetArea, sourceData, 0, pixelCount);
+        }
+    }
+}