Foundation Models Instruments Template

import FoundationModels
import SwiftUI

// MARK: - Tools

struct GenerateCraftIdeaTool: Tool {
    static let name = "generateCraftIdea"
    static let description = "Generates a craft project idea based on the user's interests."

    struct Input: Codable {
        let theme: String
    }

    func call(input: Input) async throws -> String {
        // In a real app this might query a database or use more logic
        return "Here is a craft idea based on \(input.theme): Paper Butterfly Mobile"
    }
}

struct SwitchToTutorialModeTool: Tool {
    static let name = "switchToTutorialMode"
    static let description = "Switches the experience from brainstorming to tutorial generation for the selected craft."

    struct Input: Codable {
        let selectedCraft: String
    }

    func call(input: Input) async throws -> String {
        return "Switching to tutorial mode for: \(input.selectedCraft)"
    }
}

// MARK: - Dynamic Instructions

struct BrainstormInstructions: DynamicInstructions {
    // Both tools must be listed here — omitting SwitchToTutorialModeTool
    // causes a silent failure visible only in Instruments.
    var instructions: Instructions {
        Instructions(
            """
            You are a crafting assistant. Suggest creative craft projects.
            When the user selects a craft, call switchToTutorialMode with the craft name.
            """,
            tools: [GenerateCraftIdeaTool(), SwitchToTutorialModeTool()]
        )
    }
}

// MARK: - Session

actor CraftSession {
    private let model = SystemLanguageModel.default
    private lazy var session = LanguageModelSession(
        instructions: BrainstormInstructions()
    )

    func brainstorm(prompt: String) async throws -> String {
        let response = try await session.respond(to: Prompt(prompt))
        return response.content
    }
}

// MARK: - SwiftUI View

struct CraftBrainstormView: View {
    @State private var output = "Tap to brainstorm craft ideas..."
    @State private var isLoading = false
    private let craftSession = CraftSession()

    var body: some View {
        VStack(spacing: 20) {
            Text("Craft Companion")
                .font(.largeTitle.bold())

            ScrollView {
                Text(output)
                    .padding()
                    .frame(maxWidth: .infinity, alignment: .leading)
            }
            .background(.secondarySystemBackground)
            .clipShape(RoundedRectangle(cornerRadius: 12))

            Button {
                Task { await runBrainstorm() }
            } label: {
                Label(isLoading ? "Thinking…" : "Brainstorm Ideas", systemImage: "wand.and.sparkles")
                    .frame(maxWidth: .infinity)
            }
            .buttonStyle(.borderedProminent)
            .disabled(isLoading)
        }
        .padding()
        // Profile this view with the Foundation Models Instruments template
        // (Product › Profile › Foundation Models) to see the full
        // session › request › inference › tool call hierarchy in real time.
    }

    private func runBrainstorm() async {
        isLoading = true
        defer { isLoading = false }
        do {
            output = try await craftSession.brainstorm(
                prompt: "Please generate 3 craft ideas suitable for a rainy afternoon."
            )
        } catch {
            output = "Error: \(error.localizedDescription)"
        }
    }
}

#Preview {
    CraftBrainstormView()
}