# Revised Order

- Create Order Flow ✅
- Match Order Flow ✅
- Cancel Order Flow ✅
- User Registration Flow
- Deposit Flow
- Withdraw Flow
- User Update Flow
- User Delete Flow
- Referral Flow

## Event and Command
### Command
- Has reply
- Has only one listener for the reply
- Start with a imperative verb
- cancel.order.command => (imperative verb + what + type)
-
- Is sequential
#### Reply
- Start with command name + type reply
- cancel.order.reply
### Event
- Is pub/sub and has *..n subscribers
- Doesn't have reply
- Is async
- Publisher doesn't know about successful/unsuccessful execution of the rest of logic
## Order's Create Order Flow

sequenceDiagram
autonumber
User ->> Order: create order
Order ->> Asset: get order asset (validation data)
Order ->> Order: validate order
alt if not valid
Order -->> User: error not valid
end
Order ->> Price: get market price
Order ->> Order: validate market price
alt if not valid
Order -->> User: error not valid
end
Order ->> Account: check balance
alt if not enough balance
Order -->> User: error not enough balance
end
Order ->> Database: create order with NOT_EXECUTED status
alt if database error
Order -->> User: error
end
Order ->> Database: create freeze asset command
alt if database error
Order -->> User: error
end
Order ->> User: order created response

loop
Database -) Debezium: push events
Debezium ->> Kafka: dispatch events
end

## Order's Create Order Flow After Asset is Frozen

sequenceDiagram
autonumber
Order -) Account: freeze asset
Account ->> Database: freeze user assets
alt if not enough
    Account ->> Database: create error reply
    Database -) Debezium: push events
    Debezium ->> Kafka: dispatch events
    Kafka ->> Order: cannot freeze account
else other error
    Account ->> Account: retry
else no error
    Kafka ->> Order: freeze successful reply
end

Order ->> Database: find order with id from reply
Order ->> Order: check status 
alt if other than NOT_EXECUTED
    Order ->> Order: ignore
end

alt if freeze has error
    Order ->> Order: reject order
    Order ->> Database: save rejected order
    Order ->> Database: publish order rejected event
end

alt if reply came late (> 3 minutes)
    Order ->> Order: set order status to TIMED_OUT
    Order ->> Database: save timed out order
    Order ->> Database: publish order timed out event
    Order ->> Database: publish unfreeze command
    Kafka -) Account: unfreeze
    Account ->> Database: unfreeze 
end

Order ->> Book: get order asset's book
Note over Book: PME
alt if book not found
    Order ->> Order: retry
end
Order ->> Order: set order status to NEW
Order ->> Database: publish order created event
alt if database error
Order -->> Order: retry
end
Order ->> Book: Process order


loop
Database -) Debezium: push events
Debezium ->> Kafka: dispatch events
end

## Order's Match Orders Flow

sequenceDiagram
autonumber

Order ->> Book: Process order
alt order is not bot order
    Book ->> Book: add order to book
end

Book ->> Matcher: try match
Matcher ->> Matcher: get opposite book
Matcher ->> Matcher: find opposite order
alt cannot find opposite order
    Note left of Matcher: TODO: raise error
    Matcher ->> Matcher: cannot match, add to book
end
Matcher ->> Matcher: can match
alt if cannot match
    Note left of Matcher: TODO: send alert
    Matcher ->> Matcher: cannot match, add to book
end

Matcher ->> Book: remove both order
Matcher ->> Matcher: create trade and update trade orders
Matcher ->> Matcher: notify match listeners

## Order's Match Listener Flow

sequenceDiagram
autonumber
Matcher ->> MatchListener: Notify match listener
loop for each match
    loop for both orders in match event
        MatchListener ->> Database: get order
        alt if cannot find order
            MatchListener ->> Matcher: return error
        end

        alt if order is cancelled
            MatchListener ->> Matcher: return error
        end
        MatchListener ->> Database: update order
        Note over MatchListener: calcualte total executed and deduct from original total, if less we have dust
        MatchListener ->> MatchListener: has dust?
        alt if has dust
            MatchListener ->> Database: publish unfreeze command for dust amount
        end
        alt if order is filled
            MatchListener ->> Database: publish order filled event
        else
            MatchListener ->> Database: publish order patially filled event
        end
    end
    
    MatchListener ->> Database: publish exchange command
    MatchListener ->> Database: create trade record
    MatchListener ->> Database: commit
end

loop
Database -) Debezium: push events
Debezium ->> Kafka: dispatch events
end

## Order's Cancel Order Flow

sequenceDiagram
autonumber
User ->> Order: cancel order
Order ->> Database: get order
alt if not found
    Order ->> User: not found error
end
Order ->> Order: same owner?
alt if not
    Order ->> User: ownership error
end
Order ->> Order: is pending cancel?
alt if pending cancel
    Order ->> User: return successful cancel response
end
Note over Order: [FILLED, CANCELED, REJECTED, EXPIRED, TIMED_OUT]
Order ->> Order: status is final?
alt if final
    Order ->> User: cannot cancel error
end
Order ->> Book: set status to PENDING_CANCEL
Order ->> Database: set status to PENDIG_CANCEL
Order ->> Database: publish external me cancel order
Database -) Debezium: cancel order event
Debezium ->> Kafka: publish event
Order ->> User: successful cancel response

## External ME Cancel Order Flow

sequenceDiagram
autonumber
Order -) ExternalME: cancel order
ExternalME ->> Datbase: find order
alt if not found
    ExternalME ->> Kafka: publish successful cancel
end
alt if filled
    ExternalME ->> Kafka: publish failed cancel
end
alt if anything other than [NEW, PARTIALLY_FILLED]
    ExternalME ->> Database: set status to cancelled
    ExternalME ->> Kafka: publish successful cancel
end

alt if new/partially filled
    ExternalME ->> LiquidityProvider: cancel order
    alt if not found
        Note over ExternalME: we cannot do anything
        ExternalME ->> Kafka: publish successful cancel
    else other error
        ExternalME ->> Kafka: publish failed cancel
    end
    
    ExternalME ->> Database: set status to pending cancel
end

loop check status job
    ExternalME ->> Database: get all pending cancel
    ExternalME ->> LiquidityProvider: get order
    alt if cancelled
        alt if order executed amount is more than our database after cancellation
            ExternalME ->> Kafka: publish match command
            Kafka --) ExternalME: order match reply received
            ExternalME ->> Kafka: publish successful cancel
        else
            ExternalME ->> Kafka: publish successful cancel
        end
    end
    
    ExternalME ->> Database: update order based on LP response
end

## Order Cancel Flow After External ME Cancellation

sequenceDiagram
autonumber
ExternalME --) Order: publish external cancel reply
Order ->> Database: get order

alt if not found
    Order ->> Order: ignore event
end

alt if order is filled
    Order ->> Order: ignore event
end

alt if external cancel failed
    alt if order has fills
        Order ->> Book: Set status to PARTIALLY_FILLED
        Order ->> Database: Set status to PARTIALLY_FILLED
    else if order doesn't have fills
        Order ->> Book: Set status to NEW
        Order ->> Database: Set status to NEW
    end
else if cancel was successufl
    Order ->> Book: remove order
    Order ->> Database: set statut to cancelled
    Order ->> Database: publish order cancelled event
    Order ->> Database: publish account unfreeze command
end

loop
Database -) Debezium: push events
Debezium ->> Kafka: dispatch events
end

### Order Statuses

type OrderStatus string

const (
	OrderStatusNotExecuted     OrderStatus = "NOT_EXECUTED"
	OrderStatusNew             OrderStatus = "NEW"
	OrderStatusPartiallyFilled OrderStatus = "PARTIALLY_FILLED"
	OrderStatusFilled          OrderStatus = "FILLED"
	OrderStatusCanceled        OrderStatus = "CANCELED"
	OrderStatusPendingCancel   OrderStatus = "PENDING_CANCEL"
	OrderStatusRejected        OrderStatus = "REJECTED"
	OrderStatusExpired         OrderStatus = "EXPIRED"
	OrderStatusTimedOut        OrderStatus = "TIMED_OUT"
)

    New Service:
    KYC
    Fiat Manager
    IPG
    
    Current Service:
    Auth => register with email/phone
    External or Internal Order Execution?
    Hot/Cold Wallet