/// <summary>
/// Prune out arguments that are disqualified by <paramref name="qualifier"/>.
/// </summary>
/// <param name="line"></param>
/// <param name="qualifier">Argument qualifier that is used for determining which parts to keep in the line</param>
/// <param name="lineFactory">(optional) extra line factory</param>
/// <returns>a modified <paramref name="line"/></returns>
/// <exception cref="LineException"></exception>
public static ILine Prune(this ILine line, ILineQualifier qualifier, ILineFactory lineFactory = null)
{
// Qualified parts to append. Order: tail to root.
StructList12 <ILineArgument> list = new StructList12 <ILineArgument>();
ILineArgumentQualifier lineArgumentQualifier = qualifier as ILineArgumentQualifier;
// Earliest qualified line part. The start tail, where to start appending qualified parts
ILine startTail = line;
// Line part's arguments. Order: root to tail
StructList8 <ILineArgument> tmp = new StructList8 <ILineArgument>();
// Start tail buffered args. Order: root to tail
StructList8 <ILineArgument> startTailArgsBuffer = new StructList8 <ILineArgument>();
// Add parts
for (ILine l = line; l != null; l = l.GetPreviousPart())
{
tmp.Clear();
if (l is ILineArgumentEnumerable lineArguments)
{
foreach (ILineArgument lineArgument in lineArguments)
{
tmp.Add(lineArgument);
}
}
if (l is ILineArgument argument)
{
tmp.Add(argument);
}
// Now qualify
bool linePartQualifies = true;
string parameterName, parameterValue;
for (int i = tmp.Count - 1; i >= 0; i--)
{
ILineArgument a = tmp[i];
bool argumentQualifies = true;
if (lineArgumentQualifier != null)
{
// Qualify as an argument.
if (!a.IsNonCanonicalKey())
{
argumentQualifies = lineArgumentQualifier.QualifyArgument(a);
}
// Qualify as non-canonical parameter
else if (a.TryGetParameter(out parameterName, out parameterValue))
{
// Calculate occurance index
int occIx = -1;
if (lineArgumentQualifier.NeedsOccuranceIndex)
{
occIx = 0;
for (int j = i - 1; j >= 0; j--)
{
ILineArgument b = list[j];
string parameterName2, parameterValue2;
if (b.TryGetParameter(out parameterName2, out parameterValue2))
{
continue;
}
if (parameterValue2 != null && parameterName == parameterName2)
{
occIx++;
}
}
}
argumentQualifies = lineArgumentQualifier.QualifyArgument(a, occIx);
}
}
if (!argumentQualifies)
{
tmp.RemoveAt(i);
}
linePartQualifies &= argumentQualifies;
}
// This part didn't qualify
if (!linePartQualifies)
{
// Append previous start tail to append args
if (startTailArgsBuffer.Count > 0)
{
for (int i = 0; i < startTailArgsBuffer.Count; i++)
{
list.Add(startTailArgsBuffer[i]);
}
startTailArgsBuffer.Clear();
startTail = null;
}
// Add parts that did qualify to append list
for (int i = 0; i < tmp.Count; i++)
{
list.Add(tmp[i]);
}
// preceding part might be better for start tail
startTail = l.GetPreviousPart();
}
else
// This part qualified
{
// Add to start tail buffer, in case preceding startTail fails qualifications
for (int i = 0; i < tmp.Count; i++)
{
startTailArgsBuffer.Add(tmp[i]);
}
}
}
// Append qualified parts.
ILineFactory appender1 = null;
line.TryGetAppender(out appender1);
// Nothing qualified, no start, create dummy
if (startTail == null && list.Count == 0)
{
// Create dummy
ILineFactory appender2 = null;
line.TryGetAppender(out appender2);
ILinePart dummy = null;
if (lineFactory == null || !lineFactory.TryCreate(null, out dummy))
{
if (appender2 == null || !appender2.TryCreate(null, out dummy))
{
throw new LineException(line, $"LineFactory doesn't have capability to create {nameof(ILinePart)}");
}
}
return(dummy);
}
// Append parts
ILine result = startTail;
for (int i = list.Count - 1; i >= 0; i--)
{
ILineArgument arg = list[i];
if (lineFactory == null || !lineFactory.TryCreate(result, arg, out result))
{
if (appender1 == null || !appender1.TryCreate(result, arg, out result))
{
throw new LineException(line, $"LineFactory doesn't have capability to concat {arg}");
}
}
}
return(result);
}
