/// <summary>
/// This is a recursive function. Each scenario is determined by working out 'fulfillment capabilities' starting at a particular supplier and then recurse through all other suppliers for 'unfulfilled' products
/// </summary>
/// <param name="purchaseRequirements"></param>
/// <param name="suppliers"></param>
/// <returns></returns>
FulfillmentScenario Optimize(IEnumerable <PurchaseRequirement> purchaseRequirements,
IEnumerable <Supplier> suppliers)
{
FulfillmentScenario optimalScenario = null;
// workout a possible scenario starting from one carrier
// could be done in paralel with Paralel.For
foreach (Supplier supplier in suppliers)
{
FulfillmentScenario scenario = new FulfillmentScenario();
FulfillmentCapability fulfillmentCapability = DetermineFulfillmentCapability(supplier, purchaseRequirements);
scenario.Add(fulfillmentCapability);
// determine requirements current carrier could not fulfill
IEnumerable <PurchaseRequirement> pendingRequirements = fulfillmentCapability.ProductsWithInsufficientStock.Concat(fulfillmentCapability.UnrecognizedProducts);
// recuse through other carriers if current supplier unable to fulfill all requirements
if (pendingRequirements.Count() > 0)
{
FulfillmentScenario residualFulfillmentScenario = Optimize(pendingRequirements, suppliers.Where(s => s.ID != supplier.ID));
scenario.Adopt(residualFulfillmentScenario);
}
// Determine if this scenario is the most optimal and keep track
if (optimalScenario == null || scenario.TotalCost < optimalScenario.TotalCost)
{
optimalScenario = scenario;
}
}
return(optimalScenario);
}
/// <summary>
/// Adds supplier fulfillment capability to scenario
/// </summary>
/// <param name="fulfillmentCapability"></param>
/// <exception cref="DuplicateScenarioCapabilityException"></exception>
public void Add(FulfillmentCapability fulfillmentCapability)
{
if (_supplierFulfillmentCapabilities.ContainsKey(fulfillmentCapability.Supplier.ID))
{
throw new DuplicateScenarioCapabilityException();
}
add(fulfillmentCapability);
}
/// <summary>
/// Update supplier fulfillment capability. Used when adding 'insufficient stock' items to existing supplier fulfillment capability (quote)
/// </summary>
/// <param name="fulfillmentCapability"></param>
public void Replace(FulfillmentCapability fulfillmentCapability)
{
if (_supplierFulfillmentCapabilities.TryGetValue(fulfillmentCapability.Supplier.ID,
out FulfillmentCapability original))
{
_totalCost -= original.TotalCost;
_supplierFulfillmentCapabilities.Remove(fulfillmentCapability.Supplier.ID);
}
add(fulfillmentCapability);
}
/// <summary>
/// Internal function to add fulfillment capability to list and keep track of total cost for scenario
/// </summary>
/// <param name="fulfillmentCapability"></param>
void add(FulfillmentCapability fulfillmentCapability)
{
_supplierFulfillmentCapabilities.Add(fulfillmentCapability.Supplier.ID, fulfillmentCapability);
_totalCost += fulfillmentCapability.TotalCost;
}
