From 7209f4a534def4fd36100bf0f3d04a836636c162 Mon Sep 17 00:00:00 2001
From: yoshikazu <yoshikazu@yfox.jp>
Date: Mon, 27 Jul 2026 15:38:11 +0000
Subject: [PATCH] Add FeaturePrinter

---
 Sources/Photochk/Core/FeaturePrinter.swift | 23 ++++++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 Sources/Photochk/Core/FeaturePrinter.swift

diff --git a/Sources/Photochk/Core/FeaturePrinter.swift b/Sources/Photochk/Core/FeaturePrinter.swift
new file mode 100644
index 0000000..66963cb
--- /dev/null
+++ b/Sources/Photochk/Core/FeaturePrinter.swift
@@ -0,0 +1,23 @@
+import Foundation
+import Vision
+
+/// Vision の feature print で「見た目の近さ」を測る。
+///
+/// `perform(on: URL)` は Vision 側が ImageIO でデコードするため、HEIC や RAW もそのまま渡せる。
+enum FeaturePrinter {
+    static func compute(for url: URL) async throws -> FeaturePrintObservation {
+        var request = GenerateImageFeaturePrintRequest()
+        // 縦横比が違う版（トリミング・リサイズ）でも比較できるよう、切り取らずに収める。
+        request.cropAndScaleAction = .scaleToFit
+        return try await request.perform(on: url)
+    }
+
+    /// 距離は 0 が同一。比較できない組み合わせでは nil を返す。
+    static func distance(
+        _ a: FeaturePrintObservation?,
+        _ b: FeaturePrintObservation?
+    ) -> Double? {
+        guard let a, let b else { return nil }
+        return try? a.distance(to: b)
+    }
+}