Cloud ERP with offline and online data sync features

uralia

I have many independent modules what are running in my clients work stations powered by php / mysql.

but there have some limitation. my client's demand and I feel also to overcome the limitations, now looking for a geek to get the solutions. The application will have the demands are below:

1. platform independent desktop client app, don't want to use browser. the app will connected with online database.
2. synchronization options at client hand, auto sync. if server down or client device disconnected from internet , everything will work by using of local database. when internet connection restore every data will automatic upload to server. if multiple branch sync. update time algorithm will allow.
3. this is a group of company, under it have 3 single company, every company has multiple branch, every branch has multiple warehouse to store material / product. inventory will adjust under the main umbrella.
4. others modules are HRM, Accounting, delivery, sales, purchase

any one is there to give a architecture or development guideline. i think it should developed from scratch in java or python. i want to leave php for it's limitation . or have any alternative?