How to Build a Birthday Reminder App in SwiftUI

import SwiftData; import Foundation

@Model final class Birthday {
    var name: String
    var date: Date
    var contactIdentifier: String?
    var notifyDaysBefore: Int = 1
    init(name: String, date: Date, contactIdentifier: String? = nil) {
        self.name = name; self.date = date; self.contactIdentifier = contactIdentifier
    }
    var nextBirthday: Date {
        var c = Calendar.current.dateComponents([.month, .day], from: date)
        c.year = Calendar.current.component(.year, from: .now)
        let candidate = Calendar.current.date(from: c) ?? date
        return candidate < .now
            ? Calendar.current.date(byAdding: .year, value: 1, to: candidate) ?? candidate
            : candidate
    }
    var daysUntil: Int {
        Calendar.current.dateComponents([.day], from: .now, to: nextBirthday).day ?? 0
    }
}

import SwiftUI; import SwiftData

struct BirthdayListView: View {
    @Query private var birthdays: [Birthday]
    @Environment(\.modelContext) private var context
    @State private var showAdd = false
    var sorted: [Birthday] { birthdays.sorted { $0.nextBirthday < $1.nextBirthday } }
    var body: some View {
        NavigationStack {
            List {
                ForEach(sorted) { b in
                    HStack {
                        VStack(alignment: .leading) {
                            Text(b.name).font(.headline)
                            Text(b.nextBirthday, style: .date).font(.caption).foregroundStyle(.secondary)
                        }
                        Spacer()
                        Text(b.daysUntil == 0 ? "🎂 Today!" : "in \(b.daysUntil)d")
                            .font(.subheadline).foregroundStyle(.orange)
                    }
                }
                .onDelete { offsets in offsets.forEach { context.delete(sorted[$0]) } }
            }
            .navigationTitle("Birthdays")
            .toolbar { Button { showAdd = true } label: { Image(systemName: "plus") } }
            .sheet(isPresented: $showAdd) { AddBirthdayView() }
        }
    }
}

import Contacts; import SwiftData

final class ContactsManager {
    static func importBirthdays(into context: ModelContext, existing: [Birthday]) async throws {
        let store = CNContactStore()
        guard try await store.requestAccess(for: .contacts) else { return }
        let keys: [CNKeyDescriptor] = [
            CNContactGivenNameKey as CNKeyDescriptor, CNContactFamilyNameKey as CNKeyDescriptor,
            CNContactBirthdayKey as CNKeyDescriptor, CNContactIdentifierKey as CNKeyDescriptor
        ]
        let existingIDs = Set(existing.compactMap(\.contactIdentifier))
        let req = CNContactFetchRequest(keysToFetch: keys)
        try store.enumerateContacts(with: req) { contact, _ in
            guard let comps = contact.birthday, let month = comps.month, let day = comps.day,
                  !existingIDs.contains(contact.identifier) else { return }
            let year = comps.year ?? Calendar.current.component(.year, from: .now)
            guard let date = Calendar.current.date(
                from: DateComponents(year: year, month: month, day: day)) else { return }
            let name = "\(contact.givenName) \(contact.familyName)".trimmingCharacters(in: .whitespaces)
            context.insert(Birthday(name: name, date: date, contactIdentifier: contact.identifier))
        }
        try context.save()
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN"
  "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
  <key>NSPrivacyTracking</key>
  <false/>
  <key>NSPrivacyCollectedDataTypes</key>
  <array>
    <dict>
      <key>NSPrivacyCollectedDataType</key>
      <string>NSPrivacyCollectedDataTypeContacts</string>
      <key>NSPrivacyCollectedDataTypeLinked</key>
      <false/>
      <key>NSPrivacyCollectedDataTypeTracking</key>
      <false/>
      <key>NSPrivacyCollectedDataTypePurposes</key>
      <array>
        <string>NSPrivacyCollectedDataTypePurposeAppFunctionality</string>
      </array>
    </dict>
  </array>
</dict>
</plist>