(async()=>{
  const panel=document.querySelector('#push-prompt');
  const toggle=document.querySelector('#push-toggle');
  const enable=document.querySelector('#push-enable');
  const dismiss=document.querySelector('#push-dismiss');
  const message=document.querySelector('#push-message');
  const status=document.querySelector('#push-status');
  let registration;
  let config;
  let subscription;
  const remember=()=>{try{localStorage.setItem('truenews-push-dismissed',String(Date.now()));}catch{}};
  const dismissed=()=>{try{return Date.now()-Number(localStorage.getItem('truenews-push-dismissed')||0)<30*86400000;}catch{return false;}};
  const api=async(action,value)=>{
    const response=await fetch(`/api/push/${action}`,{method:'POST',headers:{'Content-Type':'application/json'},body:JSON.stringify(value)});
    if(!response.ok)throw new Error('Could not save your preference. Please try again.');
  };
  const show=()=>{panel.hidden=false;};
  const update=()=>{
    toggle.textContent=subscription?'Notifications on':'Get new stories';
    enable.textContent=subscription?'Turn off notifications':'Enable notifications';
    message.textContent=subscription?'You’ll get a notification when a new article is published.':'Get a browser notification when a new story is published. You can turn this off anytime.';
  };
  try {
    const response=await fetch('/api/push/config');
    if(!response.ok)return;
    config=await response.json();
    if(!config.enabled)return;
    toggle.hidden=false;
    const supported=window.isSecureContext && 'serviceWorker' in navigator && 'PushManager' in window && 'Notification' in window;
    if(!supported){
      const explain=()=>{
        show();enable.hidden=true;
        const apple=/iPad|iPhone|iPod/.test(navigator.userAgent)||(navigator.platform==='MacIntel'&&navigator.maxTouchPoints>1);
        message.textContent=apple?'On iPhone or iPad, add TrueNews to your Home Screen, open it from there, then enable notifications.':'Notifications need a supported browser and a secure HTTPS connection.';
      };
      toggle.addEventListener('click',explain);
      if((/iPad|iPhone|iPod/.test(navigator.userAgent)||(navigator.platform==='MacIntel'&&navigator.maxTouchPoints>1))&&!dismissed())explain();
      dismiss.addEventListener('click',()=>{panel.hidden=true;remember();});
      return;
    }
    registration=await navigator.serviceWorker.register('/sw.js');
    await navigator.serviceWorker.ready;
    subscription=await registration.pushManager.getSubscription();
    if(subscription && Notification.permission==='granted') {
      // Restore the server record if a device revisits after a transient failure.
      await api('subscribe',subscription.toJSON()).catch(()=>{status.textContent='Could not sync notifications. You can retry or turn them off below.';});
    }
    update();
    toggle.addEventListener('click',()=>{status.textContent='';update();show();});
    dismiss.addEventListener('click',()=>{panel.hidden=true;remember();});
    enable.addEventListener('click',async()=>{
      enable.disabled=true;status.textContent='';
      try {
        if(subscription){
          await api('unsubscribe',subscription.toJSON());
          await subscription.unsubscribe();subscription=null;remember();update();status.textContent='Notifications turned off.';
        }else{
          // Permission must be requested directly from this user gesture.
          const permission=await Notification.requestPermission();
          if(permission!=='granted'){
            remember();status.textContent=permission==='denied'?'Notifications are blocked. You can change this in your browser’s site settings.':'No problem. You can enable notifications here later.';return;
          }
          const key=Uint8Array.from(atob(config.publicKey.replace(/-/g,'+').replace(/_/g,'/')),c=>c.charCodeAt(0));
          const created=await registration.pushManager.subscribe({userVisibleOnly:true,applicationServerKey:key});
          try {await api('subscribe',created.toJSON());}catch(error){await created.unsubscribe();throw error;}
          subscription=created;update();status.textContent='You’re subscribed. Watch for the next story.';
        }
      }catch(error){status.textContent=error.message || 'Could not update notifications. Please try again.';}
      finally{enable.disabled=false;}
    });
    if(!subscription && Notification.permission==='default' && !dismissed()) show();
  }catch{toggle.hidden=true;panel.hidden=true;}
})();