BizGaze_Remote/mobile/plugins/audio-route/ios/Sources/AudioRoutePlugin/AudioRoutePlugin.swift

import Foundation
import Capacitor
import AVFoundation

// Earpiece <-> speaker toggle for calls. Registered by cap sync as a real Capacitor plugin package, so it
// shows up as window.Capacitor.Plugins.AudioRoute (an app-embedded class gets stripped in release builds).
//
// ROOT CAUSE (WebKit source: Source/WebCore/platform/audio/cocoa/MediaSessionManagerCocoa.mm, confirmed by
// device telemetry): in a WKWebView the app does NOT own the AVAudioSession — WebKit's media process does.
// While WebRTC capture is active it re-pins the session to .playAndRecord with mode .videoChat, and
// .videoChat auto-implies .defaultToSpeaker. overrideOutputAudioPort(.none) means "revert to the mode
// default", which under .videoChat is the LOUDSPEAKER — so .none alone can never reach the earpiece once
// WebKit has flipped the mode. Our first .none won only because our .voiceChat mode was still in effect
// (voiceChat's default route IS the receiver); after WebKit's reconfigure it latched to speaker.
//
// THE FIX: for earpiece, set mode .voiceChat FIRST, then overrideOutputAudioPort(.none). overrideOutputAudioPort
// is a *transient* override (Apple QA1754) that every route/category change resets, and WebKit reconfigures on
// capture start / setLocalDescription / ICE-connected / renegotiation — so we also observe routeChangeNotification
// and re-assert (debounced, mismatch-only, capped) after WebKit's change settles. This reactive re-assert is the
// only lever a WKWebView host has (WebKit's internal RTCAudioSession / useManualAudio is unreachable; WebKit bug
// 167788 has left the app unable to disable WebKit's session management for 8+ years).
@objc(AudioRoutePlugin)
public class AudioRoutePlugin: CAPPlugin, CAPBridgedPlugin {
    public let identifier = "AudioRoutePlugin"
    public let jsName = "AudioRoute"
    public let pluginMethods: [CAPPluginMethod] = [
        CAPPluginMethod(name: "setSpeaker", returnType: CAPPluginReturnPromise)
    ]

    // Bump on every native change so telemetry identifies the running binary unambiguously.
    private static let nativeTag = "1.0.4-mode"

    private var wantSpeaker = false          // desired output; source of truth, re-applied on route changes
    private var pending: DispatchWorkItem?   // debounced re-assert
    private var asserts = 0                   // re-assert count this toggle (capped, anti-thrash)
    private var routeLog: [String] = []       // reason->port trail, returned to JS for diagnosis

    // Real external outputs — when one of these is active and the user wants "earpiece", we must NOT force the
    // built-in receiver (that would yank audio off the user's headset). Only correct the speaker<->receiver axis.
    private let accessoryPorts: [AVAudioSession.Port] = [
        .bluetoothHFP, .bluetoothA2DP, .bluetoothLE, .headphones, .headsetMic, .usbAudio, .carAudio, .airPlay
    ]

    override public func load() {
        let session = AVAudioSession.sharedInstance()
        // NO .defaultToSpeaker — .voiceChat's default route is the receiver, so the port override decides output.
        try? session.setCategory(.playAndRecord, mode: .voiceChat, options: [.allowBluetooth, .allowBluetoothA2DP])
        try? session.setActive(true)
        NotificationCenter.default.addObserver(self, selector: #selector(routeChanged(_:)),
                                               name: AVAudioSession.routeChangeNotification, object: nil)
    }

    deinit { NotificationCenter.default.removeObserver(self) }

    private func reasonName(_ r: UInt) -> String {
        switch r {
        case 1: return "newDev"; case 2: return "oldDev"; case 3: return "catChg"
        case 4: return "override"; case 6: return "wake"; case 7: return "noRoute"
        case 8: return "cfgChg"; default: return "unknown"
        }
    }

    private func ports() -> String {
        let outs = AVAudioSession.sharedInstance().currentRoute.outputs.map { $0.portType.rawValue }
        return outs.isEmpty ? "(none)" : outs.joined(separator: "+")
    }

    private func log(_ s: String) {
        routeLog.append(s)
        if routeLog.count > 16 { routeLog.removeFirst(routeLog.count - 16) }
    }

    @objc private func routeChanged(_ note: Notification) {
        let raw = (note.userInfo?[AVAudioSessionRouteChangeReasonKey] as? UInt) ?? 0
        log("\(reasonName(raw))>\(ports())")
        // Re-assert AFTER WebKit's change settles; coalesce bursts into one late assert so we act last.
        pending?.cancel()
        let work = DispatchWorkItem { [weak self] in self?.applyRoute() }
        pending = work
        DispatchQueue.main.asyncAfter(deadline: .now() + 0.25, execute: work)
    }

    // Nudge the route toward the desired output, acting ONLY on a real built-in speaker<->receiver mismatch so
    // our own override (which itself fires a route change) self-terminates instead of looping.
    private func applyRoute() {
        guard asserts < 6 else { log("cap"); return }   // anti-thrash: give up rather than ping-pong forever
        let s = AVAudioSession.sharedInstance()
        let outs = s.currentRoute.outputs
        let onSpeaker = outs.contains { $0.portType == .builtInSpeaker }
        let onAccessory = outs.contains { accessoryPorts.contains($0.portType) }
        if onAccessory && !wantSpeaker { log("skipAcc"); return }   // leave a real headset/BT alone
        do {
            if wantSpeaker {
                if !onSpeaker { asserts += 1; try s.overrideOutputAudioPort(.speaker); log("assert>spk") }
            } else if onSpeaker {
                asserts += 1
                // .none alone can't beat WebKit's .videoChat default (= speaker). Re-pin voiceChat first so the
                // "revert to default" the override does actually resolves to the RECEIVER.
                if s.category != .playAndRecord {
                    try s.setCategory(.playAndRecord, mode: .voiceChat, options: [.allowBluetooth, .allowBluetoothA2DP])
                    log("repinCat")
                } else if s.mode != .voiceChat {
                    try s.setMode(.voiceChat)
                    log("repinMode")
                }
                try s.overrideOutputAudioPort(.none)
                log("assert>rcv")
            }
        } catch { log("assertErr") }
    }

    private func diag(_ applied: String) -> [String: Any] {
        let s = AVAudioSession.sharedInstance()
        return [
            "route": applied,
            "native": AudioRoutePlugin.nativeTag,
            "outputs": ports(),
            "category": s.category.rawValue,
            "mode": s.mode.rawValue,
            "opts": Int(s.categoryOptions.rawValue),
            "log": routeLog.joined(separator: ",")   // route-change trail since the previous toggle
        ]
    }

    @objc func setSpeaker(_ call: CAPPluginCall) {
        wantSpeaker = call.getBool("on") ?? true
        asserts = 0
        let s = AVAudioSession.sharedInstance()
        do {
            // Earpiece: pin .voiceChat first so the very first press is correct even if WebKit already flipped
            // the mode to .videoChat. Speaker: override(.speaker) works under any mode, no mode change needed.
            if !wantSpeaker && s.category == .playAndRecord && s.mode != .voiceChat {
                try s.setMode(.voiceChat)
            }
            try s.overrideOutputAudioPort(wantSpeaker ? .speaker : .none)
            let out = diag(wantSpeaker ? "speaker" : "earpiece")
            routeLog.removeAll()   // reset the trail; next toggle reports what happened in between
            call.resolve(out)
        } catch {
            call.reject(error.localizedDescription)
        }
    }
}