A shipment service is having trouble tracking orders, which is causing issues for customers. To make things better, they are moving their database to a smart contract-based blockchain solution. This will make the process more transparent and efficient, and help with order management.

Process:

"no orders placed" if the customer has not placed any orders.
"shipped" if the order has been dispatched.
"delivered" if the last order has been successfully delivered.

The smart contract must contain the following public functions:

Input:

shipWithPin(address customerAddress, uint pin) public: This function can only be accessed by the owner (warehouse manager) and is used to mark an order as dispatched. The owner provides the customer's address and a four-digit OTP (pin) between 999 and 10,000 to verify the order.

acceptOrder(uint pin) public returns (): This function can only be accessed by the customer. After receiving the shipment at their address, the customer can mark the order as accepted by entering the OTP (pin) provided to them.

Output:

checkStatus(address customerAddress) public returns (string): This function allows customers to check the status of their own orders by providing their address. It returns a string indicating the status of the order. Possible status values include:

"no orders placed" if the customer has not placed any orders.
"shipped" if the order has been dispatched.
"delivered" if the last order has been successfully delivered.

totalCompletedDeliveries(address customerAddress) public returns (uint):This function enables customers to determine the number of successfully completed deliveries to their specific address. By providing their address, customers can retrieve the total count of completed deliveries. The owner can also use this function to check the number of successfully completed deliveries for any address.

Implement the required smart contract to help the shipment service migrate the database.

Example 1

Input/Output

Function

Sender address

Parameter

Returns

Input

shipWithPin()

Owner

(<Address 1>,1220)

Input

acceptOrder()

Address 1

(1220)

Output

checkStatus()

Owner

(<Address 1>)

"delivered"

Output

totalCompletedDeliveries()

Address 1

(<Address 1>)

1