import CryptoKit
import Foundation

enum ContentHasher {
    private static let chunkSize = 1 << 20  // 1 MB

    /// ファイル全体を読み込まずに SHA-256 を求める。
    static func sha256(of url: URL) throws -> String {
        let handle = try FileHandle(forReadingFrom: url)
        defer { try? handle.close() }

        var hasher = SHA256()
        while let chunk = try handle.read(upToCount: chunkSize), !chunk.isEmpty {
            hasher.update(data: chunk)
        }
        return hasher.finalize().map { String(format: "%02x", $0) }.joined()
    }
}