private static bool EvaluateModeAnswer(DiatonicMode mode, Guitar guitar, int stringNumber, int position, int[][] fretNumbers, string answer)
{
var pitch = guitar.GetPitch(stringNumber, position + fretNumbers[0][0]);
var combinations =
from keyNote in new[] { pitch.Note, pitch.Note.Invert() }.Distinct()
from modeName in new[] { mode.GetName(), mode.GetAlternativeName() }.Distinct()
select $"{keyNote.ToString().ToLowerInvariant()} {modeName.ToLowerInvariant()}";
return(combinations.Contains(answer));
}
private static void PrintExcercise(Guitar guitar, int stringNumber, int[][] fretNumbers, int maxFretNumber, int questionStringIndex, int questionFretIndex, int position)
{
var questionStringNumber = stringNumber + questionStringIndex;
var sb = new StringBuilder();
var stringFrets = new bool[maxFretNumber + 1];
for (var i = guitar.NumberOfStrings - 1; i >= 0; i--)
{
sb.Clear();
Array.Clear(stringFrets, 0, stringFrets.Length);
int fretNumberIndex = i - stringNumber;
int[] stringFretNumbers;
if (0 <= fretNumberIndex && fretNumberIndex < fretNumbers.Length)
{
stringFretNumbers = fretNumbers[fretNumberIndex];
for (var j = 0; j < stringFretNumbers.Length; j++)
{
stringFrets[stringFretNumbers[j]] = true;
}
}
else
{
stringFretNumbers = null;
}
sb.Append(guitar.GetPitch(i, 0).Note.ToString().PadRight(3)).Append('-').Append('|');
for (var j = 0; j < stringFrets.Length; j++)
{
sb.Append('-');
if (!stringFrets[j])
{
sb.Append('-');
}
else if (i == questionStringNumber && j == stringFretNumbers[questionFretIndex])
{
sb.Append('?');
}
else
{
sb.Append('O');
}
sb.Append('-').Append('|');
}
sb.Append('-');
Console.WriteLine(sb.ToString());
}
Console.WriteLine(new string(' ', 5) + position.ToString().PadLeft(2));
}
private static int FillFretNumbers(int[][] fretNumbers, Guitar guitar, int stringNumber, DiatonicScale scale)
{
int fretNumber = 0;
int minFretNumber = fretNumber;
int maxFretNumber = fretNumber;
using (IEnumerator <Interval> intervalEnumerator = scale.GetIntervalsAscending().GetEnumerator())
{
for (var i = 0; i < fretNumbers.Length; i++)
{
for (var j = 0; j < fretNumbers[i].Length; j++)
{
fretNumbers[i][j] = fretNumber;
if (fretNumber > maxFretNumber)
{
maxFretNumber = fretNumber;
}
intervalEnumerator.MoveNext();
fretNumber += intervalEnumerator.Current.Semitones;
}
if (stringNumber < guitar.StringIntervals.Count)
{
fretNumber -= guitar.StringIntervals[stringNumber].Semitones;
if (fretNumber < minFretNumber)
{
minFretNumber = fretNumber;
}
}
stringNumber++;
}
}
if (minFretNumber < 0)
{
ShiftFretNumbers(fretNumbers, -minFretNumber);
maxFretNumber -= minFretNumber;
}
return(maxFretNumber);
}
private static void Practice()
{
s_practiceStats = new PracticeStats();
Console.CancelKeyPress += (s, e) => PrintPracticeStats();
var guitar = new Guitar();
var random = new Random();
for (; ;)
{
var mode = (DiatonicMode)random.Next(DiatonicScale.NumberOfDegrees);
var scale = new DiatonicScale(Note.C, mode);
var pattern = (Pattern)random.Next(numberOfPatterns);
int[][] fretNumbers = CreateFretNumbers(pattern);
int stringNumber = random.Next(guitar.NumberOfStrings - fretNumbers.Length + 1);
int maxFretNumber = FillFretNumbers(fretNumbers, guitar, stringNumber, scale);
int questionStringIndex;
int questionFretIndex;
if (random.Next(10) != 0)
{
questionStringIndex = random.Next(fretNumbers.Length);
questionFretIndex = random.Next(fretNumbers[questionStringIndex].Length);
}
else
{
questionStringIndex = questionFretIndex = -1;
}
int position = random.Next(guitar.NumberOfFrets - maxFretNumber + 1);
PrintExcercise(guitar, stringNumber, fretNumbers, maxFretNumber, questionStringIndex, questionFretIndex, position);
Console.WriteLine();
Console.Write(questionStringIndex >= 0 ? "Enter scale degree: " : "Enter scale name: ");
Console.WriteLine($"({s_practiceStats.Stopwatch.Elapsed:hh':'mm':'ss})");
for (; ;)
{
var answer = Console.ReadLine()?.ToLowerInvariant();
if (answer == null || answer == "q" || answer == "quit")
{
PrintPracticeStats();
return;
}
bool isCorrectAnswer;
if (questionStringIndex >= 0)
{
DiatonicMode degree = mode;
for (var i = 0; i < fretNumbers.Length; i++)
{
for (var j = 0; j < fretNumbers[i].Length; j++)
{
if (i < questionStringIndex || j < questionFretIndex)
{
degree++;
if (degree - Ionian >= DiatonicScale.NumberOfDegrees)
{
degree -= DiatonicScale.NumberOfDegrees;
}
}
else
{
goto EndOfLoop;
}
}
}
EndOfLoop:
isCorrectAnswer = EvaluateDegreeAnswer(degree, answer);
}
else
{
isCorrectAnswer = EvaluateModeAnswer(mode, guitar, stringNumber, position, fretNumbers, answer);
}
if (isCorrectAnswer)
{
s_practiceStats.NumberOfCorrectAnswers++;
Console.WriteLine("Correct!");
break;
}
else
{
s_practiceStats.NumberOfWrongAnswers++;
Console.WriteLine("Wrong!");
}
}
Console.WriteLine();
}
}