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//
// SpeechSynthesizer.swift
// DayByDay
//
import AVFoundation
import UIKit
/// Wrapper around AVSpeechSynthesizer that selects the highest-quality
/// en-US neural voice available on the device. Falls back gracefully if
/// premium/enhanced voices haven't been downloaded yet.
final class SpeechSynthesizer {
static let shared = SpeechSynthesizer()
private let synthesizer = AVSpeechSynthesizer()
private let voice: AVSpeechSynthesisVoice?
private let haptics = UIImpactFeedbackGenerator(style: .rigid)
private init() {
self.voice = Self.bestAvailableVoice()
}
/// Speaks a pre-configured utterance directly. Used for warmup at launch.
func speakUtterance(_ utterance: AVSpeechUtterance) {
synthesizer.speak(utterance)
}
func speak(_ text: String) {
// Every speak() call is a card tap, so give a gentle tactile bump
// alongside the audio. Prepared just before firing for lowest latency.
haptics.prepare()
haptics.impactOccurred()
// Ensure speech plays through the speaker even when the silent switch is on.
try? AVAudioSession.sharedInstance().setCategory(.playback, mode: .default)
try? AVAudioSession.sharedInstance().setActive(true)
if synthesizer.isSpeaking {
synthesizer.stopSpeaking(at: .immediate)
}
let utterance = AVSpeechUtterance(string: text)
utterance.voice = voice
utterance.rate = 0.4
utterance.pitchMultiplier = 1.0
utterance.preUtteranceDelay = 0
synthesizer.speak(utterance)
}
/// Picks the best en-US voice on the device.
/// Filters for en-US, excludes novelty voices, then sorts by quality
/// descending so premium (3) > enhanced (2) > default (1).
private static func bestAvailableVoice() -> AVSpeechSynthesisVoice? {
let best = AVSpeechSynthesisVoice.speechVoices()
.filter { voice in
voice.language.hasPrefix("en-US")
&& !voice.voiceTraits.contains(.isNoveltyVoice)
}
.sorted { $0.quality.rawValue > $1.quality.rawValue }
.first
let selected = best ?? AVSpeechSynthesisVoice(language: "en-US")
print("[DayByDay] Selected voice: \(selected?.name ?? "nil"), quality: \(selected?.quality.rawValue ?? -1)")
return selected
}
}
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