public Span <int> Run(int input)
{
var programSpan = program.AsSpan();
var instructionPointer = 0;
while (true)
{
var opCodeText = programSpan[instructionPointer].ToString();
var paramModeRepository = ParameterModeRepository.ParseFromOpCode(opCodeText);
var extractor = new ParameterExtractor(paramModeRepository);
var parsedOpCode = opCodeText.Length > 1 ? int.Parse(opCodeText.Substring(opCodeText.Length - 2, 2)) : programSpan[instructionPointer];
switch (parsedOpCode)
{
case 1:
Operation(programSpan, instructionPointer, (a, b) => a + b, extractor);
instructionPointer += 4;
break;
case 2:
Operation(programSpan, instructionPointer, (a, b) => a * b, extractor);
instructionPointer += 4;
break;
case 3:
programSpan[programSpan[instructionPointer + 1]] = input;
instructionPointer += 2;
break;
case 4:
var outputValue = extractor.GetParameterValue(programSpan, 0, instructionPointer);
Console.WriteLine(outputValue);
instructionPointer += 2;
break;
case 5:
JumpToWhenTrue(programSpan, ref instructionPointer, extractor, v => v != 0);
break;
case 6:
JumpToWhenTrue(programSpan, ref instructionPointer, extractor, v => v == 0);
break;
case 7:
WriteTrueIfTrueAt(programSpan, ref instructionPointer, extractor, (a, b) => a < b);
break;
case 8:
WriteTrueIfTrueAt(programSpan, ref instructionPointer, extractor, (a, b) => a == b);
break;
case 99:
return(programSpan);
}
}
}
private static void Operation(Span <int> program, int instructionPointer, Func <int, int, int> operation, ParameterExtractor extractor)
{
var arg1 = extractor.GetParameterValue(program, 0, instructionPointer);
var arg2 = extractor.GetParameterValue(program, 1, instructionPointer);
var resultPosition = program[instructionPointer + 3];
program[resultPosition] = operation(arg1, arg2);
}
private static void JumpToWhenTrue(Span <int> programSpan, ref int instructionPointer, ParameterExtractor extractor, Func <int, bool> predicate)
{
var testValue = extractor.GetParameterValue(programSpan, 0, instructionPointer);
if (predicate(testValue))
{
instructionPointer = extractor.GetParameterValue(programSpan, 1, instructionPointer);
}
else
{
instructionPointer += 3;
}
}
private static void WriteTrueIfTrueAt(Span <int> programSpan, ref int instructionPointer, ParameterExtractor extractor, Func <int, int, bool> predicate)
{
var arg1 = extractor.GetParameterValue(programSpan, 0, instructionPointer);
var arg2 = extractor.GetParameterValue(programSpan, 1, instructionPointer);
var writeToPointer = instructionPointer + 3;
programSpan[programSpan[writeToPointer]] = predicate(arg1, arg2) ? 1 : 0;
instructionPointer += 4;
}