Topic006.swift

//
//  Topic006.swift
//  SwiftUIWeeklyLayoutChallenge
//
//  Created by treastrain on 2022/08/17.
//
import SwiftUI

fileprivate func +(left: CGSize, right: CGSize) -> CGSize {
    .init(width: left.width + right.width, height: left.height + right.height)
}

/// <doc:Topic006>
public struct Topic006View: View {
    public init() {}
    
    public var body: some View {
        #if os(iOS)
        if #available(iOS 15.0, *) {
            Topic006ContentView()
        } else {
            Text("Support for this platform is not considered.")
        }
        #else
        Text("Support for this platform is not considered.")
        #endif
    }
}

#if os(iOS)
@available(iOS 15.0, *)
fileprivate struct Topic006ContentView: View {
    @State private var isCreateNewPresented: Bool = false
    @State private var isAttachImagePresented: Bool = false
    @State private var isAttachSoundPresented: Bool = false
    
    @State private var previousOffset: CGSize = .init(width: -16, height: -16)
    @State private var draggingTranslation: CGSize = .zero
    
    var body: some View {
        ZStack(alignment: .bottomTrailing) {
            Text("後ろに位置する View")
                .frame(maxWidth: .infinity, maxHeight: .infinity)
            
            Menu(content: {
                Button(action: {
                    isCreateNewPresented = true
                }) {
                    HStack {
                        Label("新規作成", systemImage: "square.and.pencil")
                    }
                }
                Button(action: {
                    isAttachImagePresented = true
                }) {
                    HStack {
                        Label("画像を追加", systemImage: "photo.on.rectangle")
                    }
                }
                Button(action: {
                    isAttachSoundPresented = true
                }) {
                    HStack {
                        Label("音声を追加", systemImage: "mic.badge.plus")
                    }
                }
            }, label: {
                Circle()
                    .fill((isCreateNewPresented || isAttachSoundPresented || isAttachImagePresented) ? .gray : .blue)
                    .frame(width: 52, height: 52)
                    .overlay(
                        Image(systemName: "plus")
                            .font(.system(size: 24))
                            .foregroundColor(.white)
                    )
            }, primaryAction: {
                isCreateNewPresented = true
            })
            .offset(previousOffset + draggingTranslation)
            .gesture(
                DragGesture()
                    .onChanged { value in
                        draggingTranslation = value.translation
                    }
                    .onEnded { value in
                        draggingTranslation = .zero
                        previousOffset = previousOffset + value.translation
                    }
            )
        }
        .alert("新規作成", isPresented: $isCreateNewPresented) {
            Button(action: { isCreateNewPresented = false }) { Text("閉じる") }
        }
        .alert("画像を追加", isPresented: $isAttachImagePresented) {
            Button(action: { isAttachImagePresented = false }) { Text("閉じる") }
        }
        .alert("音声を追加", isPresented: $isAttachSoundPresented) {
            Button(action: { isAttachSoundPresented = false }) { Text("閉じる") }
        }
    }
}
#endif