Fix: respect external USB-C microphone input during voice message recording

[hanxiao]

Problem

When recording voice messages with an external USB-C microphone (e.g. BOYA Mini 2 wireless mic receiver), Telegram ignores the external device and records from the built-in microphone instead.

This happens because setupOutputMode calls overrideOutputAudioPort(.speaker) for voice message recording (.record(false, _, _)). Per Apple docs, this forces both output and input to built-in devices, regardless of other settings.

Other apps (Voice Memos, Camera) correctly use the external microphone. The user can verify the device is recognized in iOS Settings > Sounds & Haptics > Input.

Related: #1195, bugs.telegram.org/c/58429

Fix

After the speaker override, check availableInputs for connected external input devices (excluding built-in mic, Bluetooth, and wired headphones) and restore them as the preferred input via setPreferredInput.

• 11 lines added, 0 removed
• No behavior change when no external device is connected
• Uses try? so failures don't affect existing flows
• Tested with BOYA Mini 2 USB-C wireless mic on iPhone 17 Pro Max / iOS 26

Diff

case .record(false, _, _):
    try AVAudioSession.sharedInstance().overrideOutputAudioPort(.speaker)
    // overrideOutputAudioPort(.speaker) forces both output AND input
    // to built-in devices. If an external input device (e.g. USB-C
    // microphone) is connected, restore it as the preferred input.
    if let routes = AVAudioSession.sharedInstance().availableInputs {
        for route in routes {
            if route.portType != .builtInMic && !bluetoothPortTypes.contains(route.portType) && route.portType != .headphones {
                let _ = try? AVAudioSession.sharedInstance().setPreferredInput(route)
                break
            }
        }
    }

[CLAassistant]

All committers have signed the CLA.

[520gmail]

PR #2029发自我的 iPhone在 佛历2569年2月26日，17:40，CLAassistant ***@***.***> 写道：CLAassistant left a comment (TelegramMessenger/Telegram-iOS#2029) Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.You have signed the CLA already but the status is still pending? Let us recheck it. —Reply to this email directly, view it on GitHub, or unsubscribe.You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[520gmail]

PR #2029 志�� ***@***.***>于佛历2569年2月27日 周五07:46写道：

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