import AppKit

// Render the launcher's SF Symbol directly at every macOS icon resolution.
precondition(CommandLine.arguments.count == 2, "Usage: swift Scripts/icon.swift <output.iconset>")
let directory = URL(fileURLWithPath: CommandLine.arguments[1], isDirectory: true)
try FileManager.default.createDirectory(at: directory, withIntermediateDirectories: true)
let accent = NSColor(srgbRed: 0.95, green: 0.58, blue: 0.23, alpha: 1)
guard let symbol = NSImage(systemSymbolName: "sparkles", accessibilityDescription: nil)?
    .withSymbolConfiguration(NSImage.SymbolConfiguration(paletteColors: [accent])) else {
    fatalError("The sparkles SF Symbol is unavailable.")
}
let gradient = NSGradient(starting: NSColor(srgbRed: 0.27, green: 0.19, blue: 0.13, alpha: 1),
                          ending: NSColor(srgbRed: 0.12, green: 0.09, blue: 0.08, alpha: 1))!

for size in [16, 32, 128, 256, 512] {
    for scale in [1, 2] {
        let pixels = size * scale
        let bitmap = NSBitmapImageRep(bitmapDataPlanes: nil, pixelsWide: pixels, pixelsHigh: pixels,
                                      bitsPerSample: 8, samplesPerPixel: 4, hasAlpha: true,
                                      isPlanar: false, colorSpaceName: .deviceRGB,
                                      bytesPerRow: 0, bitsPerPixel: 0)!
        NSGraphicsContext.saveGraphicsState()
        NSGraphicsContext.current = NSGraphicsContext(bitmapImageRep: bitmap)
        let context = NSGraphicsContext.current!.cgContext
        context.scaleBy(x: CGFloat(pixels) / 1024, y: CGFloat(pixels) / 1024)
        let tile = NSBezierPath(roundedRect: NSRect(x: 100, y: 100, width: 824, height: 824),
                                xRadius: 184, yRadius: 184)
        NSGraphicsContext.saveGraphicsState()
        let shadow = NSShadow()
        shadow.shadowColor = NSColor.black.withAlphaComponent(0.28)
        shadow.shadowBlurRadius = 24
        shadow.shadowOffset = NSSize(width: 0, height: -12)
        shadow.set()
        NSColor(srgbRed: 0.12, green: 0.09, blue: 0.08, alpha: 1).setFill()
        tile.fill()
        NSGraphicsContext.restoreGraphicsState()
        gradient.draw(in: tile, angle: -90)
        NSColor.white.withAlphaComponent(0.10).setStroke()
        tile.lineWidth = 2
        tile.stroke()

        let glyphHeight: CGFloat = 540
        let glyphWidth = glyphHeight * symbol.size.width / symbol.size.height
        symbol.draw(in: NSRect(x: (1024 - glyphWidth) / 2, y: (1024 - glyphHeight) / 2,
                               width: glyphWidth, height: glyphHeight),
                    from: .zero, operation: .sourceOver, fraction: 1)
        NSGraphicsContext.restoreGraphicsState()
        let suffix = scale == 2 ? "@2x" : ""
        let output = directory.appendingPathComponent("icon_\(size)x\(size)\(suffix).png")
        guard let png = bitmap.representation(using: .png, properties: [:]) else {
            fatalError("Could not encode \(output.lastPathComponent).")
        }
        try png.write(to: output)
    }
}