How to Build a Ringtone Maker App in SwiftUI

import SwiftData
import Foundation

@Model
final class Ringtone {
    var id: UUID
    var name: String
    var sourceFileURL: URL
    var trimStart: Double   // seconds
    var trimEnd: Double     // max 30 s for standard ringtones
    var createdAt: Date

    init(name: String, sourceFileURL: URL,
         trimStart: Double = 0, trimEnd: Double = 30) {
        self.id            = UUID()
        self.name          = name
        self.sourceFileURL = sourceFileURL
        self.trimStart     = trimStart
        self.trimEnd       = min(trimEnd, trimStart + 30)
        self.createdAt     = Date()
    }

    var duration: Double { trimEnd - trimStart }
}

struct RingtoneListView: View {
    @Query(sort: \Ringtone.createdAt, order: .reverse)
    private var ringtones: [Ringtone]
    @Environment(\.modelContext) private var modelContext
    @State private var showingPicker     = false
    @State private var selectedRingtone: Ringtone?

    var body: some View {
        NavigationStack {
            List {
                ForEach(ringtones) { ringtone in
                    RingtoneRow(ringtone: ringtone)
                        .contentShape(Rectangle())
                        .onTapGesture { selectedRingtone = ringtone }
                }
                .onDelete { offsets in
                    offsets.forEach { modelContext.delete(ringtones[$0]) }
                }
            }
            .navigationTitle("My Ringtones")
            .toolbar {
                ToolbarItem(placement: .primaryAction) {
                    Button("Add", systemImage: "plus") { showingPicker = true }
                }
            }
            .sheet(isPresented: $showingPicker)  { AudioPickerView() }
            .sheet(item: $selectedRingtone) { RingtoneTrimView(ringtone: $0) }
        }
    }
}

import AVFoundation

@Observable
final class AudioTrimmer {
    var isExporting = false

    func export(ringtone: Ringtone, to outputURL: URL) async throws {
        isExporting = true
        defer { isExporting = false }

        let asset = AVURLAsset(url: ringtone.sourceFileURL)
        guard let session = AVAssetExportSession(
            asset: asset,
            presetName: AVAssetExportPresetAppleM4A
        ) else { throw TrimError.noSession }

        let start = CMTime(seconds: ringtone.trimStart, preferredTimescale: 600)
        let end   = CMTime(seconds: ringtone.trimEnd,   preferredTimescale: 600)
        session.outputURL      = outputURL
        session.outputFileType = .m4a
        session.timeRange      = CMTimeRange(start: start, end: end)

        try await withCheckedThrowingContinuation { (cont: CheckedContinuation<Void, Error>) in
            session.exportAsynchronously {
                if let err = session.error { cont.resume(throwing: err) }
                else { cont.resume() }
            }
        }
    }

    enum TrimError: Error { case noSession }
}

<?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/>
    <key>NSPrivacyAccessedAPITypes</key>
    <array>
        <dict>
            <key>NSPrivacyAccessedAPIType</key>
            <string>NSPrivacyAccessedAPICategoryFileTimestamp</string>
            <key>NSPrivacyAccessedAPITypeReasons</key>
            <array><string>C617.1</string></array>
        </dict>
    </array>
    <!-- Add NSMicrophoneUsageDescription in Info.plist only
         if you add live recording; file-based trimming alone
         does not require microphone permission -->
</dict>
</plist>