Day 47 Challenge - Habits app

ContentView.swift

//
//  ContentView.swift
//  Habits
//
//  Created by Maarten Engels on 09/11/2019.
//  Copyright © 2019 thedreamweb. All rights reserved.
//

import SwiftUI

struct Activity: Identifiable, Codable {
    let id = UUID()
    let title: String
    let description: String
    var count = 0
}

class Habits: ObservableObject {
    @Published var activities = [Activity]() {
        didSet {
            let encoder = JSONEncoder()

            if let data = try? encoder.encode(activities) {
                UserDefaults.standard.set(data, forKey: "activities")
            }
        }
    }
    
    init() {
        if let loadedActivities = UserDefaults.standard.data(forKey: "activities") {
            let decoder = JSONDecoder()
            if let decoded = try? decoder.decode([Activity].self, from: loadedActivities) {
                self.activities = decoded
                return
            }
        }

        self.activities = []
    }
    
    func increaseCount(for activityID: UUID) {
        guard let changedActivityIndex = activities.firstIndex(where: { $0.id == activityID }) else {
            return
        }
        
        var changedActivity = activities[changedActivityIndex]
        changedActivity.count += 1
        
        activities[changedActivityIndex] = changedActivity
    }
}

struct NewActivityView: View {
    @Environment(\.presentationMode) var presentationMode
    @ObservedObject var habits: Habits
    
    @State private var title = ""
    @State private var description = ""
    
    var body: some View {
        NavigationView {
            Form {
                TextField("Title", text: $title)
                TextField("Description", text: $description)
            }
            .navigationBarTitle("Add habit")
            .navigationBarItems(leading:
                Button("Back") {
                    self.presentationMode.wrappedValue.dismiss()
            }, trailing:
                Button("Save") {
                    self.saveNewHabit()
                }
            )
        }
    }
    
    func saveNewHabit() {
        let newHabit = Activity(title: title, description: description)
        habits.activities.append(newHabit)
        self.presentationMode.wrappedValue.dismiss()
    }
}

struct ContentView: View {
    @ObservedObject var habits = Habits()
    @State private var showingAddActivitySheet = false
    
    var body: some View {
        NavigationView {
            List {
                ForEach(habits.activities) { activity in
                    HStack {
                        VStack(alignment: .leading) {
                            Text(activity.title).font(.headline)
                            Text(activity.description).font(.subheadline)
                        }
                        Spacer()
                        Button(action: {
                            self.habits.increaseCount(for: activity.id)
                        }) {
                            Text("Did it!")
                                .foregroundColor(Color.white)
                                .font(.headline)
                                .padding(8)
                                .background(Color.blue)
                                .clipShape(Capsule())
                        }
                        Text(String(activity.count)).font(.largeTitle)
                            .padding(8)
                            .clipShape(Circle())
                            .overlay(Circle().stroke(lineWidth: 2))
                        .shadow(radius: 2)
                    }
                }.onDelete(perform: removeItems)
                
            }
                .navigationBarTitle("It's not a habit, it's cool, I feel alive")
                .navigationBarItems(trailing:
                    Button(action: { self.showingAddActivitySheet.toggle() }) {
                        Image(systemName: "plus")
                    }
                )
                .sheet(isPresented: $showingAddActivitySheet) {
                    NewActivityView(habits: self.habits)
            }
        }
    }
    
    
    
    func removeItems(at offset: IndexSet) {
        habits.activities.remove(atOffsets: offset)
    }
}

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