move basic mod scanning into the toolkit (#532)

2 files changed, 163 insertions, 0 deletions

diff --git a/src/StardewModdingAPI.Toolkit/Framework/ModScanning/ModFolder.cs b/src/StardewModdingAPI.Toolkit/Framework/ModScanning/ModFolder.cs
new file mode 100644
index 00000000..9b6853b4
--- /dev/null
+++ b/src/StardewModdingAPI.Toolkit/Framework/ModScanning/ModFolder.cs
@@ -0,0 +1,60 @@
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using StardewModdingAPI.Toolkit.Serialisation.Models;
+
+namespace StardewModdingAPI.Toolkit.Framework.ModScanning
+{
+    /// <summary>The info about a mod read from its folder.</summary>
+    public class ModFolder
+    {
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>The Mods subfolder containing this mod.</summary>
+        public DirectoryInfo SearchDirectory { get; }
+
+        /// <summary>The folder containing manifest.json.</summary>
+        public DirectoryInfo ActualDirectory { get; }
+
+        /// <summary>The mod manifest.</summary>
+        public Manifest Manifest { get; }
+
+        /// <summary>The error which occurred parsing the manifest, if any.</summary>
+        public string ManifestParseError { get; }
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance when a mod wasn't found in a folder.</summary>
+        /// <param name="searchDirectory">The directory that was searched.</param>
+        public ModFolder(DirectoryInfo searchDirectory)
+        {
+            this.SearchDirectory = searchDirectory;
+        }
+
+        /// <summary>Construct an instance.</summary>
+        /// <param name="searchDirectory">The Mods subfolder containing this mod.</param>
+        /// <param name="actualDirectory">The folder containing manifest.json.</param>
+        /// <param name="manifest">The mod manifest.</param>
+        /// <param name="manifestParseError">The error which occurred parsing the manifest, if any.</param>
+        public ModFolder(DirectoryInfo searchDirectory, DirectoryInfo actualDirectory, Manifest manifest, string manifestParseError = null)
+        {
+            this.SearchDirectory = searchDirectory;
+            this.ActualDirectory = actualDirectory;
+            this.Manifest = manifest;
+            this.ManifestParseError = manifestParseError;
+        }
+
+        /// <summary>Get the update keys for a mod.</summary>
+        /// <param name="manifest">The mod manifest.</param>
+        public IEnumerable<string> GetUpdateKeys(Manifest manifest)
+        {
+            return
+                (manifest.UpdateKeys ?? new string[0])
+                .Where(p => !string.IsNullOrWhiteSpace(p))
+                .ToArray();
+        }
+    }
+}
diff --git a/src/StardewModdingAPI.Toolkit/Framework/ModScanning/ModScanner.cs b/src/StardewModdingAPI.Toolkit/Framework/ModScanning/ModScanner.cs
new file mode 100644
index 00000000..d3662c9c
--- /dev/null
+++ b/src/StardewModdingAPI.Toolkit/Framework/ModScanning/ModScanner.cs
@@ -0,0 +1,103 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using StardewModdingAPI.Toolkit.Serialisation;
+using StardewModdingAPI.Toolkit.Serialisation.Models;
+
+namespace StardewModdingAPI.Toolkit.Framework.ModScanning
+{
+    /// <summary>Scans folders for mod data.</summary>
+    public class ModScanner
+    {
+        /*********
+        ** Properties
+        *********/
+        /// <summary>The JSON helper with which to read manifests.</summary>
+        private readonly JsonHelper JsonHelper;
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="jsonHelper">The JSON helper with which to read manifests.</param>
+        public ModScanner(JsonHelper jsonHelper)
+        {
+            this.JsonHelper = jsonHelper;
+        }
+
+        /// <summary>Extract information about all mods in the given folder.</summary>
+        /// <param name="rootPath">The root folder containing mods.</param>
+        public IEnumerable<ModFolder> GetModFolders(string rootPath)
+        {
+            foreach (DirectoryInfo folder in new DirectoryInfo(rootPath).EnumerateDirectories())
+                yield return this.ReadFolder(rootPath, folder);
+        }
+
+        /// <summary>Extract information from a mod folder.</summary>
+        /// <param name="rootPath">The root folder containing mods.</param>
+        /// <param name="searchFolder">The folder to search for a mod.</param>
+        public ModFolder ReadFolder(string rootPath, DirectoryInfo searchFolder)
+        {
+            // find manifest.json
+            FileInfo manifestFile = this.FindManifest(searchFolder);
+            if (manifestFile == null)
+                return new ModFolder(searchFolder);
+
+            // read mod info
+            Manifest manifest = null;
+            string manifestError = null;
+            {
+                try
+                {
+                    manifest = this.JsonHelper.ReadJsonFile<Manifest>(manifestFile.FullName);
+                    if (manifest == null)
+                    {
+                        manifestError = File.Exists(manifestFile.FullName)
+                            ? "its manifest is invalid."
+                            : "it doesn't have a manifest.";
+                    }
+                }
+                catch (SParseException ex)
+                {
+                    manifestError = $"parsing its manifest failed: {ex.Message}";
+                }
+                catch (Exception ex)
+                {
+                    manifestError = $"parsing its manifest failed:\n{ex}";
+                }
+            }
+
+            return new ModFolder(searchFolder, manifestFile.Directory, manifest, manifestError);
+        }
+
+
+        /*********
+        ** Private methods
+        *********/
+        /// <summary>Find the manifest for a mod folder.</summary>
+        /// <param name="folder">The folder to search.</param>
+        private FileInfo FindManifest(DirectoryInfo folder)
+        {
+            while (true)
+            {
+                // check for manifest in current folder
+                FileInfo file = new FileInfo(Path.Combine(folder.FullName, "manifest.json"));
+                if (file.Exists)
+                    return file;
+
+                // check for single subfolder
+                FileSystemInfo[] entries = folder.EnumerateFileSystemInfos().Take(2).ToArray();
+                if (entries.Length == 1 && entries[0] is DirectoryInfo subfolder)
+                {
+                    folder = subfolder;
+                    continue;
+                }
+
+                // not found
+                return null;
+            }
+        }
+    }
+}