SQL & PL/SQL :: Fetch Records Based On Status Priority

I have a table with below syntax and insert statements.

-- Table creation
-----------------------
create table order_test (oid number,
orderno number,
ordername varchar2(100),
orderstatus varchar2(50),
orderseq number);
----------------------------------
-- Insert statements

[Code]....

The Output looks like below

OID|ORDERNO|ORDERNAME|ORDERSTATUS|ORDERSEQ
1 |100 |ORD1 |INPROGRESS |1
7 |100 |ORD1 |START |4
3 |100 |ORD1 |START |2
4 |100 |ORD1 |INPROGRESS |3
6 |101 |ORD2 |CANCELLED |3
2 |101 |ORD2 |INPROGRESS |2
5 |101 |ORD2 |COMPLETE |1
8 |102 |ORD3 |COMPLETE |1
9 |103 |ORD4 |CANCELLED |1
10 |103 |ORD4 |CANCELLED |2

Now, the below rules should be applied to get the output..

1) If status is same, then fetch max(seq) record
2) If status is different, then apply below priority to fetch the records

Start - Priority 1 (High)
In Progress - Priority 2
Cancelled - Priority 3
Complete - Priority 4 (Lowest)

Means, the output for each order should look like below.

OID|ORDERNO|ORDERNAME|ORDERSTATUS|ORDERSEQ
3 |100 |ORD1 |START |2
2 |101 |ORD2 |INPROGRESS |2
8 |102 |ORD3 |COMPLETE |1
10 |103 |ORD4 |CANCELLED |2

how to do it.