AppIconMaker.swift

//
//  AppIconMakerDemo.swift
//  SwiftUI40
//
//  Created by Mateo on 6/13/22.
//

// base from this:
// https://www.youtube.com/watch?v=iNCXmq99mjw

// Note:
// You must set the key in your info:
// NSPhotoLibraryAddUsageDescription

import SwiftUI
import PhotosUI

struct AppIconMaker<IconView: View>: View {
    let icon: IconView

    @State private var showSaveAlert = false
    @State private var saveIsSuccessful = true

    var iconView: some View {
        Color.clear
            .aspectRatio(1, contentMode: .fit)
        // make the icon exactly 1024x1024
        // this create 342x342
            // Scale is points / pixels, set the image size to exactly 1024 pixel
//            .frame(width: 1024 / UIScreen.main.scale)
            // this create 1024x1024 (not sure if this is correct, but it works out)
            .frame(width: 1024)
            .overlay {
                icon
            }
    }

    var body: some View {
        VStack {
            ZStack {
                LinearGradient(colors: [.green, .yellow, .orange, .red, .purple, .blue], startPoint: .top, endPoint: .bottomTrailing)
                    .ignoresSafeArea()
                    .overlay(alignment: .top) {
                        VStack {
                            Text("App Icon Maker")
                                .font(.largeTitle.bold())
                                .foregroundColor(.mint)
                                .shadow(color: .red, radius: 5)
                            Text("Press \"Save to Image\" button to save the icon image to the photo album")
                                .multilineTextAlignment(.center)
                                .font(.footnote)
                                .padding(.horizontal)
                                .frame(width: UIScreen.main.bounds.width)
                        }
                    }
                iconView
                    .border(.mint, width: 8)
                    .scaleEffect(UIScreen.main.bounds.width / 1024)  // try to fit on screen
                let _ = print(UIScreen.main.bounds.width)
            }
            Button {
                let renderer = ImageRenderer(content: iconView)
                UIImpactFeedbackGenerator(style: .medium).impactOccurred()
                showSaveAlert = true
                if let image = renderer.uiImage {
                    UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil)
                    saveIsSuccessful = true
                } else {
                    saveIsSuccessful = false
                }
            } label: {
                Label("Save to Image", systemImage: "photo.on.rectangle.angled")
                    .frame(maxWidth: .infinity, alignment: .center)
            }
            .padding(.horizontal)
            .buttonStyle(.borderedProminent)
            .controlSize(.large)
        }
        // can only have one .alert modifier!
        .alert(isPresented: $showSaveAlert) {
            alertView
        }
    }

    var alertView: Alert {
        saveIsSuccessful ?
            Alert(
                title: Text("Success"),
                message: Text("The app icon is saved to photo album.")
            )
        :
            Alert(
                title: Text("Failure"),
                message: Text("The app icon save to photo album failed.")
            )
    }
}

struct AppIconMakerDemo: View {
    var iconView: some View {
        createAwardView(title: "100% Accurate Archer", date: .now)
    }

    var body: some View {
        AppIconMaker(icon: iconView)
    }

    // all sizing parameters must be scale to the 1024x1024 pixel square
    func createAwardView(title: String, date: Date) -> some View {
        ZStack {
            Color.yellow
            VStack(spacing: 0) {
                Spacer()
                Image(systemName: "figure.archery")
                    .resizable()
                    .aspectRatio(1, contentMode: .fit)
                    .frame(width: 1024)
                    .minimumScaleFactor(0.1)
                    .padding()
                    .shadow(color: .red, radius: 25)
                Spacer()
                VStack {
                    // must size thing large in 1024x1024 pixels square size
                    Text(title)
                        .font(.system(size: 90, weight: .heavy, design: .rounded))
                    // the dateTime .month() format is correct on screen
                    // but when feed through `ImageRenderer`, it appears it's using a different locale so
                    // the month instead of "June", it's "M06"
//                    Text(date, format: .dateTime.day().month(.wide).year())
                    // this way its formatted correctly, but I don't want the time part
                    Text(date.formatted())
                        .font(.system(size: 80))
                }
                .offset(x: 0, y: -10)
            }
        }
    }
}

struct ImageRendererDemo_Previews: PreviewProvider {
    static var previews: some View {
        AppIconMakerDemo()
    }
}