🌍 Localize queries

Sources/MasKit/Controllers/StoreSearch.swift

@@ -31,6 +31,11 @@ extension StoreSearch {
             URLQueryItem(name: "entity", value: "macSoftware"),
             URLQueryItem(name: "term", value: appName),
         ]
+
+        if let country = country {
+            components.queryItems!.append(country)
+        }
+
         return components.url
     }
 
@@ -44,6 +49,24 @@ extension StoreSearch {
         }
 
         components.queryItems = [URLQueryItem(name: "id", value: "\(appId)")]
+
+        if let country = country {
+            components.queryItems!.append(country)
+        }
+
         return components.url
     }
+
+    private var country: URLQueryItem? {
+        // CommerceKit and StoreFoundation don't seem to expose the region of the Apple ID signed
+        // into the App Store. Instead, we'll make an educated guess that it matches the currently
+        // selected locale in macOS. This obviously isn't always going to match, but it's probably
+        // better than passing no "country" at all to the iTunes Search API.
+        // https://affiliate.itunes.apple.com/resources/documentation/itunes-store-web-service-search-api/
+        guard let region = Locale.autoupdatingCurrent.regionCode else {
+            return nil
+        }
+
+        return URLQueryItem(name: "country", value: region)
+    }
 }

Tests/MasKitTests/Controllers/StoreSearchSpec.swift

@@ -6,6 +6,7 @@
 //  Copyright © 2019 mas-cli. All rights reserved.
 //
 
+import Foundation
 import Nimble
 import PromiseKit
 import Quick
@@ -26,19 +27,21 @@ struct StoreSearchForTesting: StoreSearch {
 public class StoreSearchSpec: QuickSpec {
     override public func spec() {
         let storeSearch = StoreSearchForTesting()
+        let region = Locale.autoupdatingCurrent.regionCode!
 
         describe("url string") {
             it("contains the app name") {
                 let appName = "myapp"
                 let urlString = storeSearch.searchURL(for: appName)?.absoluteString
-                expect(urlString) == "https://itunes.apple.com/search?media=software&entity=macSoftware&term=\(appName)"
+                expect(urlString) == "https://itunes.apple.com/search?"
+                    + "media=software&entity=macSoftware&term=\(appName)&country=\(region)"
             }
             it("contains the encoded app name") {
                 let appName = "My App"
                 let appNameEncoded = "My%20App"
                 let urlString = storeSearch.searchURL(for: appName)?.absoluteString
-                expect(urlString)
-                    == "https://itunes.apple.com/search?media=software&entity=macSoftware&term=\(appNameEncoded)"
+                expect(urlString) == "https://itunes.apple.com/search?"
+                    + "media=software&entity=macSoftware&term=\(appNameEncoded)&country=\(region)"
             }
             // Find a character that causes addingPercentEncoding(withAllowedCharacters to return nil
             xit("is nil when app name cannot be url encoded") {