BottomSheet.swift

//
//  ContentView.swift
//  Shared
//
//  Created by Chris Eidhof on 05.05.22.
//

import SwiftUI

struct ContentView: View {
    @State var sheet = false
    var body: some View {
        RoundedRectangle(cornerRadius: 5)
            .fill(Color.purple)
            .onTapGesture {
                sheet.toggle()
            }
            .padding(20)
        .frame(maxHeight: .infinity)
        .bottomSheet(isActive: $sheet) {
            VStack {
                Text(String(repeating: "Hello world ", count: 10))
            }
        }
    }
}

extension View {
    func bottomSheet<Content: View>(isActive: Binding<Bool>, @ViewBuilder content: @escaping () -> Content) -> some View {
        modifier(BottomSheet(isActive: isActive, sheetContent: content))
    }
}

struct BottomSheet<C: View>: ViewModifier {
    var isActive: Binding<Bool>
    @ViewBuilder var sheetContent: () -> C
    
    func body(content: Content) -> some View {
        GeometryReader { proxy in
            content
                .padding(proxy.safeAreaInsets)
                .frame(maxWidth: .infinity, maxHeight: .infinity)
                .safeAreaInset(edge: .bottom) {
                    if isActive.wrappedValue {
                        VStack(spacing: 0) {
                            sheetContent()
                                .background(.thinMaterial)
                        }
                        .transition(.move(edge: .bottom))
                        .padding(.bottom, proxy.safeAreaInsets.bottom)
                    }
                }
                .edgesIgnoringSafeArea(.all)
        }
        .animation(.default.speed(0.1), value: isActive.wrappedValue)
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}