try implementing a command that can search the index for packages

Sources/apk/Index/ApkIndexRepository.swift

@@ -0,0 +1,30 @@
+/*
+ * darwin-apk © 2024 Gay Pizza Specifications
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import Foundation
+import CryptoKit
+
+public struct ApkIndexRepository {
+  public let name: String
+  public let arch: String
+  public let discriminator: String
+
+  private static func resolveApkIndex(_ repo: String, _ arch: String)
+    -> String { "\(repo)/\(arch)/APKINDEX.tar.gz" }
+
+  public var url: URL {
+    URL(string: Self.resolveApkIndex(self.name, self.arch))!
+  }
+
+  public var localName: String { "APKINDEX.\(discriminator).tar.gz" }
+
+  public init(name repo: String, arch: String) {
+    self.name = repo
+    self.arch = arch
+
+    let urlSHA1Digest = Data(Insecure.SHA1.hash(data: Data(Self.resolveApkIndex(repo, arch).utf8)))
+    self.discriminator = urlSHA1Digest.subdata(in: 0..<3).map { String(format: "%02x", $0) }.joined()
+  }
+}