import AppKit

let arguments = CommandLine.arguments
guard arguments.count > 3 else {
    print("Usage: swift process_icon.swift <input_path> <output_path> <hex_color>")
    exit(1)
}

let inputPath = arguments[1]
let outputPath = arguments[2]
let hexColor = arguments[3].replacingOccurrences(of: "#", with: "")
let scaleFactor = arguments.count > 4 ? Double(arguments[4]) ?? 0.8 : 0.8

func colorFromHex(_ hex: String) -> NSColor {
    var rgbValue: UInt64 = 0
    Scanner(string: hex).scanHexInt64(&rgbValue)
    let r = CGFloat((rgbValue & 0xFF0000) >> 16) / 255.0
    let g = CGFloat((rgbValue & 0x00FF00) >> 8) / 255.0
    let b = CGFloat(rgbValue & 0x0000FF) / 255.0
    return NSColor(red: r, green: g, blue: b, alpha: 1.0)
}

guard let inputImage = NSImage(contentsOfFile: inputPath) else {
    print("Error: Could not load input image")
    exit(1)
}

// Fixed size for launcher icon (e.g. 1024x1024)
let size = NSSize(width: 1024, height: 1024)
let outputImage = NSImage(size: size)

outputImage.lockFocus()

// Fill background
let backgroundColor = colorFromHex(hexColor)
backgroundColor.set()
NSBezierPath(rect: NSRect(origin: .zero, size: size)).fill()

// Draw input image centered
let inputSize = inputImage.size
let ratio = min(size.width / inputSize.width, size.height / inputSize.height) * CGFloat(scaleFactor)
let targetSize = NSSize(width: inputSize.width * ratio, height: inputSize.height * ratio)
let origin = NSPoint(x: (size.width - targetSize.width) / 2, y: (size.height - targetSize.height) / 2)

inputImage.draw(in: NSRect(origin: origin, size: targetSize), from: .zero, operation: .sourceOver, fraction: 1.0)

outputImage.unlockFocus()

guard let tiffData = outputImage.tiffRepresentation,
      let bitmapImage = NSBitmapImageRep(data: tiffData),
      let pngData = bitmapImage.representation(using: .png, properties: [:]) else {
    print("Error: Could not convert to PNG")
    exit(1)
}

do {
    try pngData.write(to: URL(fileURLWithPath: outputPath))
    print("Success: \(outputPath) created")
} catch {
    print("Error: Could not write file: \(error)")
    exit(1)
}