Hardeep was born in India and is now a permanent resident of Australia. He spends most of his time working off the coast of Singapore on an oil rig for a Saudi Arabian company. He signed a contract for this job while he was in Australia. For the last five years, Hardeep's wife has lived in Australia with their four children. Hardeep and his wife purchased a home in Melbourne four years ago, and they have a joint bank account with National Australia Bank in Melbourne, which earns interest. Hardeep's salary is paid into this account. Hardeep and his wife also have a share portfolio in India that generates dividend income. Hardeep gets one month off from work every fourth month and he spends his time off with his family in Australia. 

Required: 

Discuss whether Hardeep is a resident of Australia for tax purposes and how his salary, interest income, and dividend income would be taxed. Where relevant, refer to cases, tax rulings, and legislation.