/// <summary>
/// Add a feature assignment to the aggregate pipeline
/// </summary>
/// <param name="feature"></param>
public override void Add(AssignmentExpression feature)
{
IExpression fExpression = feature.Value;
string fName = GetFeatureName(feature);//feature.Member.ToString();
var featureFType = fExpression.GetType();
string featureContent = null;
if (featureFType == typeof(NameExpression))
{
var aggTree = AddAggregateTreeFromField(fExpression as NameExpression);
aggTree.Name = fName;
_aggregateJobTrees.Add(aggTree);
// var member = (fExpression as NameExpression).Member?.ToString();
// //In some cases we might just use the field
// if (string.IsNullOrEmpty(member)) member = fExpression.ToString();
// featureContent = $"groupFields[\"{fName}\"] = " + "new BsonDocument { { \"$first\", \"$" + member + "\" } };";
}
else if (fExpression.IsDonutAggregateFunction())
{
//We're dealing with an aggregate call
var aggregateTree = AddAggregateTreeFromCall(fExpression as CallExpression);
aggregateTree.Name = fName;
_aggregateJobTrees.Add(aggregateTree);
var functionType = _donutFnResolver.GetFunctionType(fExpression as CallExpression);
switch (functionType)
{
case DonutFunctionType.GroupField:
HasGroupingFields = true;
break;
case DonutFunctionType.Project:
HasProjection = true;
break;
case DonutFunctionType.GroupKey:
HasGroupingKeys = true;
break;
case DonutFunctionType.Filter:
HasFilters = true;
break;
}
}
else
{
//This is not a donut aggregate
throw new NotImplementedException(fExpression.ToString());
}
}
public static bool IsDonutNativeFeature(this AssignmentExpression fExpr)
{
var fExpression = fExpr.Value;
if (fExpression is CallExpression callExpr)
{
var df = new DonutFunctions();
if (df.IsAggregate(callExpr))
{
return(false);
}
var fnType = df.GetFunctionType(callExpr);
return(fnType == DonutFunctionType.Donut);
}
return(false);
}
/// <summary>
///
/// </summary>
/// <param name="callExpression"></param>
/// <param name="feature"></param>
/// <returns></returns>
public FeatureFunctionsCodeResult GenerateFeatureFunctionCall(CallExpression callExpression, AssignmentExpression feature = null)
{
var fnDict = new DonutFunctions();
var isAggregate = fnDict.IsAggregate(callExpression);
var functionType = fnDict.GetFunctionType(callExpression);
Clean();
_expVisitor.Clear();
var strValues = VisitCall(callExpression, null, _expVisitor);
if (string.IsNullOrEmpty(strValues))
{
return(null);
}
if (isAggregate)
{
var aggregateField = new BsonDocument();
if (feature == null)
{
try
{
aggregateField = BsonDocument.Parse(strValues);
}
catch (Exception ex)
{
Trace.WriteLine($"Failed to parse expression: {callExpression}\nError: {ex.Message}");
return(null);
}
}
else
{
aggregateField[feature.Member.ToString()] = BsonDocument.Parse(strValues);
}
var result = new FeatureFunctionsCodeResult(functionType, aggregateField.ToString());
return(result);
}
else
{
return(new FeatureFunctionsCodeResult(strValues));
}
}