smart_printer/smart_printer/PrintService.swift

import Cocoa
import PDFKit
import UniformTypeIdentifiers

enum PrintService {
    static func print(urls: [URL]) {
        guard !urls.isEmpty else { return }

        for url in urls {
            let accessed = url.startAccessingSecurityScopedResource()
            defer {
                if accessed { url.stopAccessingSecurityScopedResource() }
            }
            printFile(at: url)
        }
    }

    private static func printFile(at url: URL) {
        let type = UTType(filenameExtension: url.pathExtension) ?? .data

        if type.conforms(to: .pdf), let document = PDFDocument(url: url) {
            printPDF(document)
        } else if type.conforms(to: .image), let image = NSImage(contentsOf: url) {
            printImage(image)
        } else if type.conforms(to: .plainText) || type.conforms(to: .text),
                  let text = try? String(contentsOf: url, encoding: .utf8) {
            printText(text)
        } else if type.conforms(to: .rtf),
                  let data = try? Data(contentsOf: url),
                  let attributed = NSAttributedString(rtf: data, documentAttributes: nil) {
            printAttributedText(attributed)
        } else if type.conforms(to: .html),
                  let data = try? Data(contentsOf: url),
                  let attributed = NSAttributedString(html: data, documentAttributes: nil) {
            printAttributedText(attributed)
        } else {
            showUnsupportedAlert(for: url)
        }
    }

    private static func printPDF(_ document: PDFDocument) {
        let printInfo = configuredPrintInfo()
        guard let operation = document.printOperation(
            for: printInfo,
            scalingMode: .pageScaleToFit,
            autoRotate: true
        ) else { return }
        operation.run()
    }

    private static func printImage(_ image: NSImage) {
        let size = image.size
        guard size.width > 0, size.height > 0 else { return }

        let imageView = NSImageView(frame: NSRect(origin: .zero, size: size))
        imageView.image = image
        imageView.imageScaling = .scaleProportionallyUpOrDown

        let operation = NSPrintOperation(view: imageView, printInfo: configuredPrintInfo())
        operation.run()
    }

    private static func printText(_ text: String) {
        printAttributedText(NSAttributedString(string: text))
    }

    private static func printAttributedText(_ text: NSAttributedString) {
        let textView = NSTextView(frame: NSRect(x: 0, y: 0, width: 612, height: 792))
        textView.textStorage?.setAttributedString(text)
        textView.isEditable = false

        let operation = NSPrintOperation(view: textView, printInfo: configuredPrintInfo())
        operation.run()
    }

    private static func configuredPrintInfo() -> NSPrintInfo {
        let printInfo = NSPrintInfo.shared.copy() as! NSPrintInfo
        let printerName = AppSettings.effectiveDefaultPrinter
        if let printer = NSPrinter(name: printerName) {
            printInfo.printer = printer
        }
        return printInfo
    }

    private static func showUnsupportedAlert(for url: URL) {
        let alert = NSAlert()
        alert.messageText = "Unsupported File"
        alert.informativeText = "\"\(url.lastPathComponent)\" cannot be printed."
        alert.alertStyle = .warning
        alert.addButton(withTitle: "OK")
        alert.runModal()
    }
}