How to Build a Calorie Tracker App in SwiftUI

import SwiftData
import Foundation

enum MealType: String, Codable, CaseIterable {
    case breakfast, lunch, dinner, snack
}

@Model
final class FoodEntry {
    var id: UUID = UUID()
    var name: String
    var calories: Double
    var protein: Double
    var carbs: Double
    var fat: Double
    var servingGrams: Double
    var mealType: MealType
    var loggedAt: Date = Date()

    init(name: String, calories: Double, protein: Double,
         carbs: Double, fat: Double,
         servingGrams: Double = 100,
         mealType: MealType = .lunch) {
        self.name = name; self.calories = calories
        self.protein = protein; self.carbs = carbs
        self.fat = fat; self.servingGrams = servingGrams
        self.mealType = mealType
    }
}

import SwiftUI
import SwiftData
import Charts

struct DashboardView: View {
    @Query(filter: #Predicate<FoodEntry> {
        $0.loggedAt >= Calendar.current.startOfDay(for: .now)
    }, sort: \FoodEntry.loggedAt) private var todayEntries: [FoodEntry]

    let goal: Double = 2000
    var total: Double { todayEntries.reduce(0) { $0 + $1.calories } }

    var body: some View {
        NavigationStack {
            ScrollView {
                VStack(spacing: 28) {
                    Gauge(value: total, in: 0...goal) {
                        Text("kcal").font(.caption)
                    } currentValueLabel: {
                        Text(Int(total), format: .number).font(.title2.bold())
                    }
                    .gaugeStyle(.accessoryCircular)
                    .scaleEffect(2.4).frame(height: 150)

                    Chart(todayEntries) { entry in
                        BarMark(x: .value("Meal", entry.mealType.rawValue.capitalized),
                                y: .value("kcal", entry.calories))
                        .foregroundStyle(by: .value("Meal", entry.mealType.rawValue))
                    }
                    .frame(height: 180).padding(.horizontal)
                }
                .padding(.top, 24)
            }
            .navigationTitle("Today")
            .toolbar {
                ToolbarItem(placement: .primaryAction) {
                    NavigationLink(destination: SearchFoodView()) {
                        Image(systemName: "plus.circle.fill").font(.title2)
                    }
                }
            }
        }
    }
}

import SwiftUI
import SwiftData

struct SearchFoodView: View {
    @Environment(\.modelContext) private var modelContext
    @Environment(\.dismiss) private var dismiss
    @State private var query = ""
    @State private var results: [NutritionItem] = []
    @State private var isLoading = false

    var body: some View {
        List(results) { item in
            Button { logFood(item) } label: {
                VStack(alignment: .leading, spacing: 2) {
                    Text(item.name).font(.headline)
                    Text("\(Int(item.kcalPer100g)) kcal · P \(Int(item.protein))g · C \(Int(item.carbs))g · F \(Int(item.fat))g")
                        .font(.caption).foregroundStyle(.secondary)
                }
            }
        }
        .searchable(text: $query, prompt: "Search foods…")
        .task(id: query) {
            guard query.count > 2 else { results = []; return }
            isLoading = true
            results = (try? await OpenFoodFactsService.search(query)) ?? []
            isLoading = false
        }
        .overlay { if isLoading { ProgressView() } }
        .navigationTitle("Add Food")
        .navigationBarTitleDisplayMode(.inline)
        .toolbar {
            ToolbarItem(placement: .cancellationAction) {
                Button("Cancel") { dismiss() }
            }
        }
    }

    private func logFood(_ item: NutritionItem) {
        modelContext.insert(FoodEntry(name: item.name, calories: item.kcalPer100g,
                                     protein: item.protein, carbs: item.carbs, fat: item.fat))
        dismiss()
    }
}

<?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>NSPrivacyAccessedAPITypes</key>
  <array>
    <dict>
      <key>NSPrivacyAccessedAPIType</key>
      <string>NSPrivacyAccessedAPICategoryUserDefaults</string>
      <key>NSPrivacyAccessedAPITypeReasons</key>
      <array><string>CA92.1</string></array>
    </dict>
  </array>
  <key>NSPrivacyCollectedDataTypes</key>
  <array>
    <dict>
      <key>NSPrivacyCollectedDataType</key>
      <string>NSPrivacyCollectedDataTypeHealth</string>
      <key>NSPrivacyCollectedDataTypeLinked</key><false/>
      <key>NSPrivacyCollectedDataTypeTracking</key><false/>
      <key>NSPrivacyCollectedDataTypePurposes</key>
      <array><string>NSPrivacyCollectedDataTypePurposeAppFunctionality</string></array>
    </dict>
  </array>
</dict>
</plist>