ScrollingEmojiView.swift

import SwiftUI

extension BinaryInteger {
    var evenOddDirection: Double {
        self.isMultiple(of: 2) ? 1 : -1
    }
}

struct ScrollingEmojiView: View {
    @State private var direction = 1.0

    @Environment(\.accessibilityReduceMotion) var reduceMotion


    let emojis: [String] = {
        // change this to however you want to generate random emoji
        func randomEmoji() -> String {
            String(allEmojis.randomElement()!.character)
        }

        let rows = 15
        var previouslyChosenEmoji = ""
        return (0...rows).map { _ in
            (0...20).map { _ in
                var emoji = randomEmoji()
                while emoji == previouslyChosenEmoji {
                    emoji = randomEmoji()
                }
                previouslyChosenEmoji = emoji
                return emoji
            }
            .joined(separator: "  ")
        }
    }()

    var body: some View {
        GeometryReader { geo in
            VStack(spacing: 10) {
                ForEach(emojis.indices, id: \.self) { index in
                    Text(emojis[index])
                        .fixedSize(horizontal: true, vertical: false)
                        .font(.system(size: 50))
                        .offset(x: reduceMotion ? 0 : direction * index.evenOddDirection * geo.size.width / 2, y: 0)
                        .animation(.linear(duration: 30).repeatForever(autoreverses: true), value: direction)
                }
            }
            .rotationEffect(.degrees(-15))
            .frame(width: geo.size.width, height: geo.size.height)
            .clipped()
        }
        .onAppear {
            direction = -direction
        }
    }
}


struct ScrollingEmojiView_Previews: PreviewProvider {
    static var previews: some View {
        ScrollingEmojiView()
            .edgesIgnoringSafeArea(.all)
    }
}