Foundation Models Framework

import SwiftUI
import FoundationModels

// 1. Define a structured output type the model will populate
@Generable
struct Recipe {
    @Guide(description: "The name of the dish")
    var name: String

    @Guide(description: "A one-sentence description of the dish")
    var description: String

    @Guide(description: "List of main ingredients")
    var ingredients: [String]

    @Guide(description: "Estimated preparation time in minutes")
    var prepTimeMinutes: Int
}

@MainActor
class RecipeViewModel: ObservableObject {
    @Published var recipe: Recipe?
    @Published var isLoading = false
    @Published var errorMessage: String?

    private let model = SystemLanguageModel.default

    func suggestRecipe(for ingredient: String) async {
        guard SystemLanguageModel.isAvailable else {
            errorMessage = "Apple Intelligence is not available on this device."
            return
        }

        isLoading = true
        errorMessage = nil

        let session = LanguageModelSession(model: model)

        do {
            let prompt = "Suggest a simple recipe that features \(ingredient) as the star ingredient."
            let result: Recipe = try await session.respond(to: prompt, generating: Recipe.self)
            recipe = result
        } catch {
            errorMessage = error.localizedDescription
        }

        isLoading = false
    }
}

struct RecipeSuggesterView: View {
    @StateObject private var viewModel = RecipeViewModel()
    @State private var ingredient = "salmon"

    var body: some View {
        NavigationStack {
            Form {
                Section("Ingredient") {
                    TextField("Enter an ingredient", text: $ingredient)
                }
                Button("Suggest Recipe") {
                    Task { await viewModel.suggestRecipe(for: ingredient) }
                }
                .disabled(viewModel.isLoading)

                if viewModel.isLoading {
                    ProgressView("Thinking on-device…")
                }

                if let recipe = viewModel.recipe {
                    Section(recipe.name) {
                        Text(recipe.description)
                            .foregroundStyle(.secondary)
                        Text("Prep time: \(recipe.prepTimeMinutes) min")
                            .font(.caption)
                        ForEach(recipe.ingredients, id: \.self) { item in
                            Label(item, systemImage: "fork.knife")
                        }
                    }
                }

                if let error = viewModel.errorMessage {
                    Text(error).foregroundStyle(.red)
                }
            }
            .navigationTitle("Recipe Suggester")
        }
    }
}

#Preview {
    RecipeSuggesterView()
}