Sequence diagrams for backend

Sequence diagrams

Buy and sell routes

@startuml
actor client as C
participant server as S
database Database  as DB

C->S: /api/trading/{buy,sell} of stock S at price P
group if market currently open
 
S->S: get cur_price of S & current portfolio balance
group if (sufficient funds / stocks) && (cur_price ACCEPTABLE (w.r.t P))
 S->DB: start TXN
 S->DB: update client portfolio
 S->DB: insert new trade & end TXN
 DB-->S: OK
 S-->C: return updated portfolio
 else otherwise
 S-->C: failed
end
else otherwise
S-->C: failed - market closed
end
@enduml