try implementing a command that can search the index for packages

Sources/dpk-cli/Subcommands/DpkSearchCommand.swift

@@ -0,0 +1,83 @@
+/*
+ * darwin-apk © 2024 Gay Pizza Specifications
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import Foundation
+import ArgumentParser
+import darwin_apk
+
+struct DpkSearchCommand: AsyncParsableCommand {
+  static let configuration = CommandConfiguration(
+    commandName: "search",
+    abstract: "Search for packages with a pattern matching name and description",
+    aliases: [ "s" ])
+
+  @Flag
+  var nameOnly: Bool = false
+
+  @Argument
+  var patterns: [String]
+
+  func run() async throws(ExitCode) {
+    let re: [Regex<_StringProcessing.AnyRegexOutput>]
+    do {
+      re = try patterns.map(Regex.init)
+    } catch {
+      print("Bad pattern \(error.localizedDescription)")
+      throw .validationFailure
+    }
+
+    let repositories: [String], architectures: [String]
+    do {
+      repositories = try await PropertyFile.read(name: "repositories")
+    } catch {
+      print("Failed to read repositories: \(error.localizedDescription)")
+      throw .failure
+    }
+    do {
+      architectures = try await PropertyFile.read(name: "arch")
+    } catch {
+      print("Failed to read arch: \(error.localizedDescription)")
+      throw .failure
+    }
+
+    let localRepositories = repositories.flatMap { repo in
+      architectures.map { arch in
+        URL(filePath: ApkIndexRepository(name: repo, arch: arch).localName, directoryHint: .notDirectory)
+      }
+    }
+    let index: ApkIndex
+    do {
+      index = ApkIndex.merge(try localRepositories.map(ApkIndex.init))
+    } catch {
+      print("Failed to build package index: \(error.localizedDescription)")
+      throw .failure
+    }
+
+    do {
+      for package in index.packages {
+        for pattern in re {
+          if try
+              pattern.firstMatch(in: package.name) != nil ||
+              (!self.nameOnly && pattern.firstMatch(in: package.packageDescription) != nil) {
+            print(package.shortDescription)
+            break
+          }
+        }
+      }
+    } catch {
+      print("Something went wrong: \(error.localizedDescription)")
+      throw .failure
+    }
+  }
+}
+
+struct PropertyFile {
+  static func read(name: String) async throws -> [String] {
+    try await URL(filePath: name, directoryHint: .notDirectory).lines
+      .map { $0.trimmingCharacters(in: .whitespaces) }
+      .filter { !$0.isEmpty && $0.first != "#" }  // Ignore empty & commented lines
+      .reduce(into: [String]()) { $0.append($1) }
+  }
+}