// Regenerates the app icon PNGs from the same geometry as Branding/logo.svg.
//
//   cd apps/ios
//   swift Branding/make-icons.swift Koins/Assets.xcassets/AppIcon.appiconset
//
// iOS cannot use SVG for app icons, so the SVG is the source artwork and this
// script produces the raster the asset catalog needs. It also writes
// Branding/logo-light.png (white ground, black mark).
import AppKit
import CoreGraphics
import Foundation

// Draws the same geometry as Branding/logo.svg with CoreGraphics, because iOS
// app icons must be raster images.
func drawIcon(size: CGFloat, inverted: Bool = false) -> CGImage? {
  let scale = size / 1024.0
  let colorSpace = CGColorSpaceCreateDeviceRGB()
  guard let context = CGContext(data: nil,
                               width: Int(size),
                               height: Int(size),
                               bitsPerComponent: 8,
                               bytesPerRow: 0,
                               space: colorSpace,
                               bitmapInfo: CGImageAlphaInfo.noneSkipLast.rawValue) else { return nil }

  let background = inverted ? NSColor.white : NSColor.black
  let foreground = inverted ? NSColor.black : NSColor.white
  context.setFillColor(background.cgColor)
  context.fill(CGRect(x: 0, y: 0, width: size, height: size))

  context.setStrokeColor(foreground.cgColor)
  context.setLineWidth(118 * scale)
  context.setLineCap(.butt)
  context.setLineJoin(.miter)

  func point(_ x: CGFloat, _ y: CGFloat) -> CGPoint {
    // SVG y grows downwards, CoreGraphics grows upwards.
    CGPoint(x: x * scale, y: size - y * scale)
  }

  // Left leg continuing into the central V (one path, so the top corner is a
  // clean miter rather than two overlapping strokes).
  context.beginPath()
  context.move(to: point(279, 758))
  context.addLine(to: point(279, 280))
  context.addLine(to: point(512, 640))
  context.strokePath()

  // Right leg, mirrored.
  context.beginPath()
  context.move(to: point(745, 758))
  context.addLine(to: point(745, 280))
  context.addLine(to: point(512, 640))
  context.strokePath()

  // Full-width bar across the base.
  context.beginPath()
  context.move(to: point(220, 699))
  context.addLine(to: point(804, 699))
  context.strokePath()

  return context.makeImage()
}

func write(_ image: CGImage, to path: String) {
  let rep = NSBitmapImageRep(cgImage: image)
  guard let data = rep.representation(using: .png, properties: [:]) else { return }
  try? data.write(to: URL(fileURLWithPath: path))
  print("wrote \(path)")
}

let outputDir = CommandLine.arguments.count > 1 ? CommandLine.arguments[1] : "/tmp"
try? FileManager.default.createDirectory(atPath: outputDir, withIntermediateDirectories: true)

if let icon = drawIcon(size: 1024) {
  write(icon, to: "\(outputDir)/AppIcon-1024.png")
}
// A light variant, handy for other surfaces (white background, black mark).
if let light = drawIcon(size: 1024, inverted: true) {
  write(light, to: "\(outputDir)/AppIcon-light-1024.png")
}