GenerateIcon.swift

import AppKit

private let outputDirectory = URL(fileURLWithPath: CommandLine.arguments[1], isDirectory: true)
private let sizes = [16, 32, 64, 128, 256, 512, 1024]

for size in sizes {
    autoreleasepool {
        let image = NSImage(size: NSSize(width: size, height: size))
        image.lockFocus()

        let inset = CGFloat(size) * 0.08
        let roundedRect = NSRect(
            x: inset,
            y: inset,
            width: CGFloat(size) - inset * 2,
            height: CGFloat(size) - inset * 2
        )
        let clipPath = NSBezierPath(roundedRect: roundedRect, xRadius: CGFloat(size) * 0.22, yRadius: CGFloat(size) * 0.22)
        clipPath.addClip()

        let gradient = NSGradient(colors: [
            NSColor(calibratedRed: 0.06, green: 0.10, blue: 0.23, alpha: 1.0),
            NSColor(calibratedRed: 0.12, green: 0.24, blue: 0.53, alpha: 1.0),
            NSColor(calibratedRed: 0.97, green: 0.53, blue: 0.18, alpha: 1.0)
        ])!
        gradient.draw(in: roundedRect, angle: -55)

        NSColor(calibratedWhite: 1.0, alpha: 0.14).setFill()
        NSBezierPath(ovalIn: NSRect(
            x: CGFloat(size) * 0.18,
            y: CGFloat(size) * 0.56,
            width: CGFloat(size) * 0.52,
            height: CGFloat(size) * 0.52
        )).fill()

        NSColor(calibratedRed: 1.0, green: 0.88, blue: 0.46, alpha: 1.0).setFill()
        NSBezierPath(ovalIn: NSRect(
            x: CGFloat(size) * 0.60,
            y: CGFloat(size) * 0.60,
            width: CGFloat(size) * 0.16,
            height: CGFloat(size) * 0.16
        )).fill()

        let moonRect = NSRect(
            x: CGFloat(size) * 0.24,
            y: CGFloat(size) * 0.24,
            width: CGFloat(size) * 0.42,
            height: CGFloat(size) * 0.42
        )
        NSColor.white.setFill()
        NSBezierPath(ovalIn: moonRect).fill()
        NSColor(calibratedRed: 0.12, green: 0.24, blue: 0.53, alpha: 1.0).setFill()
        NSBezierPath(ovalIn: moonRect.offsetBy(dx: CGFloat(size) * 0.11, dy: CGFloat(size) * 0.03)).fill()

        let slash = NSBezierPath()
        slash.lineWidth = max(CGFloat(size) * 0.07, 2.0)
        slash.lineCapStyle = .round
        slash.move(to: NSPoint(x: CGFloat(size) * 0.26, y: CGFloat(size) * 0.24))
        slash.line(to: NSPoint(x: CGFloat(size) * 0.76, y: CGFloat(size) * 0.74))
        NSColor.white.setStroke()
        slash.stroke()

        image.unlockFocus()

        guard
            let tiff = image.tiffRepresentation,
            let bitmap = NSBitmapImageRep(data: tiff),
            let pngData = bitmap.representation(using: .png, properties: [:])
        else {
            fputs("Failed to generate icon at size \(size)\n", stderr)
            exit(1)
        }

        let fileName: String
        switch size {
        case 16:
            fileName = "icon_16x16.png"
        case 32:
            fileName = "icon_16x16@2x.png"
        case 64:
            fileName = "icon_32x32@2x.png"
        case 128:
            fileName = "icon_128x128.png"
        case 256:
            fileName = "icon_128x128@2x.png"
        case 512:
            fileName = "icon_256x256@2x.png"
        case 1024:
            fileName = "icon_512x512@2x.png"
        default:
            fileName = "icon_\(size)x\(size).png"
        }

        do {
            try FileManager.default.createDirectory(at: outputDirectory, withIntermediateDirectories: true)
            try pngData.write(to: outputDirectory.appendingPathComponent(fileName))

            if size == 32 {
                try pngData.write(to: outputDirectory.appendingPathComponent("icon_32x32.png"))
            } else if size == 256 {
                try pngData.write(to: outputDirectory.appendingPathComponent("icon_256x256.png"))
            } else if size == 512 {
                try pngData.write(to: outputDirectory.appendingPathComponent("icon_512x512.png"))
            }
        } catch {
            fputs("Failed to write icon at size \(size): \(error)\n", stderr)
            exit(1)
        }
    }
}