// Browser prompt and worker objects stay outside Alpine's reactive state.
export function setupPWA({installAvailable, updateAvailable, installed, failed}) {
    let prompt;
    let registration;
    const cleanup = [];
    const listen = (target, name, handler) => {
        target.addEventListener(name, handler);
        cleanup.push(() => target.removeEventListener(name, handler));
    };
    const standalone = () => window.matchMedia('(display-mode: standalone)').matches || !!navigator.standalone;
    installed(standalone());
    listen(window, 'beforeinstallprompt', event => {
        event.preventDefault();
        prompt = event;
        installAvailable(true);
    });
    listen(window, 'appinstalled', () => {
        prompt = undefined;
        installAvailable(false);
        installed(true);
    });

    let destroyed = false;
    if ('serviceWorker' in navigator) {
        let controlled = !!navigator.serviceWorker.controller;
        listen(navigator.serviceWorker, 'controllerchange', () => {
            if (controlled) window.location.reload();
            controlled = true;
        });
        navigator.serviceWorker.register('./sw.js', {scope: './', type: 'module', updateViaCache: 'none'})
            .then(value => {
                if (destroyed) return;
                registration = value;
                const showUpdate = () => updateAvailable(!!registration.waiting);
                showUpdate();
                listen(registration, 'updatefound', () => {
                    if (registration.installing) listen(registration.installing, 'statechange', showUpdate);
                });
            }).catch(() => { if (!destroyed) failed(); });
    }
    return {
        async install() {
            if (!prompt) return;
            const pending = prompt;
            prompt = undefined;
            installAvailable(false);
            try {
                await pending.prompt();
                await pending.userChoice;
            } catch { /* Manual installation guidance remains available. */ }
        },
        update() {
            registration?.waiting?.postMessage('ACTIVATE_UPDATE');
        },
        destroy() {
            destroyed = true;
            cleanup.forEach(remove => remove());
        },
    };
}