// SGF host wrapper only; the shared purchasing package remains unchanged.
document.addEventListener('DOMContentLoaded', () => {
    const dirty = new Set();
    let pending=0;
    for(const form of document.querySelectorAll('form[data-action]')){
        const submit=form.onsubmit;
        if(typeof submit!=='function')continue;
        form.onsubmit=async e=>{
            pending++;
            try{await submit.call(form,e);if(!document.querySelector('#error')?.textContent.trim())dirty.delete(form);}
            finally{pending--;}
        };
    }
    document.addEventListener('input', e => { const form=e.target.closest('form');if(form)dirty.add(form); });
    window.addEventListener('beforeunload', e => { if(dirty.size||pending){e.preventDefault();e.returnValue='';} });
    const back=document.querySelector('[data-sgf-module-back]');
    back?.addEventListener('click', e => {
        if(pending){e.preventDefault();document.querySelector('#error').textContent='Aguarde a conclusão da operação antes de sair.';return;}
        if(!dirty.size)return;
        e.preventDefault();
        const dialog=document.createElement('dialog');
        dialog.setAttribute('aria-label','Alterações por guardar');
        dialog.innerHTML='<h2>Alterações por guardar</h2><p>Guarde, descarte ou cancele a saída deste percurso.</p><p role="alert"></p><button data-save>Guardar e continuar</button> <button data-discard>Descartar e continuar</button> <button data-cancel>Cancelar</button>';
        document.body.append(dialog);dialog.showModal();
        const close=()=>{dialog.close();dialog.remove();back.focus();};
        dialog.querySelector('[data-cancel]').onclick=close;
        dialog.addEventListener('cancel',e=>{e.preventDefault();close();});
        dialog.querySelector('[data-discard]').onclick=()=>{dirty.clear();location.assign(back.href);};
        dialog.querySelector('[data-save]').onclick=async()=>{
            for(const b of dialog.querySelectorAll('button'))b.disabled=true;
            try{
                if(dirty.size>1)throw Error('Guarde cada formulário no percurso original antes de sair. O contexto foi mantido.');
                for(const form of [...dirty]){
                    if(!form.isConnected){dirty.delete(form);continue;}
                    if(!form.reportValidity())throw Error('Corrija os campos. O contexto foi mantido.');
                    if(typeof form.onsubmit!=='function')throw Error('Guarde no formulário original antes de sair.');
                    // Existing package handlers validate, post and report errors in #error.
                    // Successful handlers reload their own page; this destination supersedes
                    // that reload only after the original promise has completed successfully.
                    await form.onsubmit({preventDefault(){}});
                    if(document.querySelector('#error')?.textContent.trim())throw Error('A gravação falhou. O contexto foi mantido.');
                    dirty.delete(form);
                }
                location.assign(back.href);
            }catch(error){dialog.querySelector('[role=alert]').textContent=error.message;}
            finally{for(const b of dialog.querySelectorAll('button'))b.disabled=false;}
        };
    });
});