1 files changed, 85 insertions, 0 deletions
diff --git a/src/SMAPI/Framework/Models/ModDataID.cs b/src/SMAPI/Framework/Models/ModDataID.cs
new file mode 100644
index 00000000..d19434fa
--- /dev/null
+++ b/src/SMAPI/Framework/Models/ModDataID.cs
@@ -0,0 +1,85 @@
+using System;
+using System.Linq;
+using Newtonsoft.Json;
+
+namespace StardewModdingAPI.Framework.Models
+{
+    /// <summary>Uniquely identifies a mod in SMAPI's internal data.</summary>
+    /// <remarks>
+    /// This represents a custom format which uniquely identifies a mod across all versions, even
+    /// if its field values change or it doesn't specify a unique ID. This is mapped to a string
+    /// with the following format:
+    /// 
+    /// 1. If the mod's identifier changed over time, multiple variants can be separated by the <c>|</c>
+    ///    character.
+    /// 2. Each variant can take one of two forms:
+    ///    - A simple string matching the mod's UniqueID value.
+    ///    - A JSON structure containing any of three manifest fields (ID, Name, and Author) to match.
+    /// </remarks>
+    internal class ModDataID
+    {
+        /*********
+        ** Properties
+        *********/
+        /// <summary>The unique sets of field values which identify this mod.</summary>
+        private readonly FieldSnapshot[] Snapshots;
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        public ModDataID() { }
+
+        /// <summary>Construct an instance.</summary>
+        /// <param name="data">The mod identifier string (see remarks on <see cref="ModDataID"/>).</param>
+        public ModDataID(string data)
+        {
+            this.Snapshots =
+                (
+                    from string part in data.Split('|')
+                    let str = part.Trim()
+                    select str.StartsWith("{")
+                        ? JsonConvert.DeserializeObject<FieldSnapshot>(str)
+                        : new FieldSnapshot { ID = str }
+                )
+                .ToArray();
+        }
+
+        /// <summary>Get whether this ID matches a given mod manifest.</summary>
+        /// <param name="id">The mod's unique ID, or a substitute ID if it isn't set in the manifest.</param>
+        /// <param name="manifest">The manifest to check.</param>
+        public bool Matches(string id, IManifest manifest)
+        {
+            return this.Snapshots.Any(snapshot =>
+                snapshot.ID.Equals(id, StringComparison.InvariantCultureIgnoreCase)
+                && (
+                    snapshot.Author == null
+                    || snapshot.Author.Equals(manifest.Author, StringComparison.InvariantCultureIgnoreCase)
+                    || (manifest.ExtraFields.ContainsKey("Authour") && snapshot.Author.Equals(manifest.ExtraFields["Authour"].ToString(), StringComparison.InvariantCultureIgnoreCase))
+                )
+                && (snapshot.Name == null || snapshot.Name.Equals(manifest.Name, StringComparison.InvariantCultureIgnoreCase))
+            );
+        }
+
+
+        /*********
+        ** Private models
+        *********/
+        /// <summary>A unique set of fields which identifies the mod.</summary>
+        private class FieldSnapshot
+        {
+            /*********
+            ** Accessors
+            *********/
+            /// <summary>The unique mod ID.</summary>
+            public string ID { get; set; }
+
+            /// <summary>The mod name, or <c>null</c> to ignore the mod name.</summary>
+            public string Name { get; set; }
+
+            /// <summary>The author name, or <c>null</c> to ignore the author.</summary>
+            public string Author { get; set; }
+        }
+    }
+}