//Define the Pattern Interface and List of Handler Objects

//Define the IApprover interface to be used as the "blueprint" for the main application classes.
//This interface defines the ProcessRequest method. This method represents the core functionality within the Chain Of Responsibility pattern,
//and will either perform the required processing or decide to pass the request onto the next object in the chain.
public interface IApprover
{
void ProcessRequest(Purchase purchase);
}

//The Director class (object) represents the first element in the chain.
//This class inherits from the IApprover interface, and therefore implements the ProcessRequest method.
//The class defines a private variable (m_successor) of type IApprover, which will store the object that represents the next element in the chain.
//In this case, the object would be of type VicePresident.
//The Director class (object) will automatically approve any purchase orders that have an amount less than 10000.00.
//If the value exceeds 10000.00, the request will be passed onto the VicePresident class (object) for approval.
public class Director : IApprover
{
private IApprover _mSuccessor;

public Director(IApprover successor)
{
_mSuccessor = successor;
}

public void ProcessRequest(Purchase purchase)
{
if (purchase.Amount < 10000.0)
{
Console.WriteLine("{0} approved request {1}", GetType().Name, purchase.PurchaseId);
}
else if (_mSuccessor != null)
{
_mSuccessor.ProcessRequest(purchase);
}
}
}

//The VicePresident class (object) represents the second element in the chain.
//This class inherits from the IApprover interface, and thefore implements the ProcessRequest method.
//The class defines a private variable (m_successor) of type IApprover, which will store the object that represents the next element in the chain.
//In this case, the object would be of type President.
//The VicePresident class (object) will automatically approve any purchase orders that have an amount less than 25000.00.
//If the value exceeds 25000.00, the request will be passed onto the President class (object) for approval.
public class VicePresident : IApprover
{
private IApprover _mSuccessor;

public VicePresident(IApprover successor)
{
_mSuccessor = successor;
}

public void ProcessRequest(Purchase purchase)
{
if (purchase.Amount < 25000.0)
{
Console.WriteLine("{0} approved request {1}", GetType().Name, purchase.PurchaseId);
}
else if (_mSuccessor != null)
{
_mSuccessor.ProcessRequest(purchase);
}
}
}

//The President class (object) represents the final element in the chain.
//This class inherits from the IApprover interface, and thefore implements the ProcessRequest method.
//The President class (object) will only approve purchase orders that have an amount less than 100000.00.
public class President : IApprover
{
public President()
{

}

public void ProcessRequest(Purchase purchase)
{
if (purchase.Amount < 100000.0)
{
Console.WriteLine("{0} approved request {1}", GetType().Name, purchase.PurchaseId);
}
else)
{
Console.WriteLine("{0} requires an executive meeting!", purchase.PurchaseId);
}
}
}