flowchart TB
id1[POST /login to customer]
id2[GET /customer/discount]
id3["GET /customer/discount(vendorID)"]
id4["POST /checkout"]
id1 -- create customer session id --> id2
id2 -- view list of vendors with discount --> a
a[["select all vendors where
isDiscount = true
OR start < time < end"]]
a --> id3
id3 -- view list of meals available --> id4
id4 --> check[["check order qty vs available qty"]]
check --> notOK{"not ok, error"}
check --> ok{"ok"}
ok --> a1[["PUT reduce qty from Discount table"]]
a1 --> a2[["INSERT into Orders and OrderDetail"]]