//R4.2 - Implement the convert method
public static object Convert(object Input, string InputFormat, string OutputFormat)
{
//We add the known converters here
RegisterFileConverter(new ConverterJpgPng());
List <ConverterStack> ConverterStacks = new List <ConverterStack>();
TheValidConverterStack = new ConverterStack();
//find an appropriate converter stack and execute
AddConvertersWhichCanConvertTheInputFormat(ConverterStacks, InputFormat, OutputFormat); //which are guaranteed to convert the inputformat
int MaximumStackDepth = 10;
if (!ValidStackFound)
{
for (int i = 2; i <= MaximumStackDepth; i++)
{
List <ConverterStack> TheLongestStacks = new List <ConverterStack>();
var query = from ConverterStack cs in ConverterStacks where cs.StackDepth == i - 1 select cs;
TheLongestStacks = query.ToList();
foreach (ConverterStack cs in TheLongestStacks)
{
foreach (IFileConverter fc in FileConvertersAvailable)
{
if (fc.InputFileFormat == cs.Output)
{
cs.Stack.Add(fc);
}
ConverterStacks.Add(cs);
if (cs.Output == OutputFormat)
{
TheValidConverterStack = cs;
ValidStackFound = true;
break;
}
}
if (ValidStackFound)
{
break;
}
}
if (ValidStackFound)
{
break;
}
}
if (!ValidStackFound)
{
throw new Exception("Conversion is not possible");
}
return(null);
}
else
{
return(ApplyTheValidConverterStack(Input, TheValidConverterStack));
}
}
private static object ApplyTheValidConverterStack(object Input, ConverterStack TheValidConverterStack)
{
object input = Input.ToString();
object output = null;
foreach (IFileConverter FileConverterInstance in TheValidConverterStack.Stack)
{
output = FileConverterInstance.Convert(input);
}
return(output);
}
private static void AddConvertersWhichCanConvertTheInputFormat(List <ConverterStack> ConverterStacks, string pInputFormat, string pOutputFormat)
{
foreach (IFileConverter fc in FileConvertersAvailable)
{
bool CanConvertFromInput = fc.InputFileFormat == pInputFormat;
if (CanConvertFromInput)
{
//add Qualifying Converters to Stack
List <IFileConverter> ConvertersWhichCanConvertInput = new List <IFileConverter>();
ConvertersWhichCanConvertInput.Add(fc);
//We will add converters to the lists in these objects to generate chains of converters
ConverterStack NewConverterStack = new ConverterStack(fc.InputFileFormat, fc.OutputFileFormat, ConvertersWhichCanConvertInput, 1);
ConverterStacks.Add(NewConverterStack);
bool CanConvertToOutput = fc.OutputFileFormat == pOutputFormat;
if (CanConvertToOutput)
{
ValidStackFound = true;
TheValidConverterStack = NewConverterStack;
}
}
}
}
