import AppKit
import Testing
@testable import Conjure

@Test @MainActor
func launcherFadesStayAtViewportEdgesAfterScrollingAndResizing() throws {
    _ = NSApplication.shared
    let scroll = LauncherScrollView(frame: NSRect(x: 0, y: 0, width: 200, height: 120))
    scroll.documentView = NSView(frame: NSRect(x: 0, y: 0, width: 200, height: 600))
    for height in [120, 240] {
        scroll.frame.size.height = CGFloat(height)
        scroll.contentView.scroll(to: NSPoint(x: 0, y: 80))
        scroll.layoutSubtreeIfNeeded()
        let mask = try #require(scroll.layer?.mask)
        let context = try #require(CGContext(data: nil, width: 200, height: height,
            bitsPerComponent: 8, bytesPerRow: 800, space: CGColorSpaceCreateDeviceRGB(),
            bitmapInfo: CGImageAlphaInfo.premultipliedLast.rawValue))
        mask.render(in: context)
        let pixels = try #require(context.data?.assumingMemoryBound(to: UInt8.self))
        func alpha(_ y: Int) -> UInt8 { pixels[y * 800 + 100 * 4 + 3] }
        #expect(alpha(0) < 20)
        #expect(alpha(8) > 80 && alpha(8) < 180)
        #expect(alpha(20) == 255)
        #expect(alpha(height / 2) == 255)
        #expect(alpha(height - 21) == 255)
        #expect(alpha(height - 9) > 80 && alpha(height - 9) < 180)
        #expect(alpha(height - 1) < 20)
    }
}