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Neuer Dialog berechnet aus den Sitzungs-Bewertungen je Schüler eine Mitarbeitsnote (H1/H2/Gesamtjahr), mit editierbarer Aspekt-Gewichtung, Trendanzeige und Übernahme als Grade (Category=Participation).
77 lines
3.4 KiB
C#
77 lines
3.4 KiB
C#
using LehrerApp.Core.Models;
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namespace LehrerApp.Core.Services;
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public class GradingService
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{
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public string CalculateGrade(double achieved, double maximum, List<GradingKeyEntry> key)
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{
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if (maximum <= 0) return "-";
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var percent = achieved / maximum * 100.0;
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return key.OrderByDescending(k => k.MinPercent)
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.FirstOrDefault(k => percent >= k.MinPercent)
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?.Grade ?? key.OrderBy(k => k.MinPercent).First().Grade;
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}
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public static List<GradingKeyEntry> DefaultKey1To6() =>
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[
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new() { Grade = "1", MinPercent = 87.5 },
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new() { Grade = "2", MinPercent = 75.0 },
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new() { Grade = "3", MinPercent = 62.5 },
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new() { Grade = "4", MinPercent = 50.0 },
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new() { Grade = "5", MinPercent = 25.0 },
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new() { Grade = "6", MinPercent = 0.0 },
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];
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public static List<GradingKeyEntry> DefaultKey0To15() =>
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[
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new() { Grade = "15", MinPercent = 95.0 },
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new() { Grade = "14", MinPercent = 90.0 },
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new() { Grade = "13", MinPercent = 85.0 },
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new() { Grade = "12", MinPercent = 80.0 },
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new() { Grade = "11", MinPercent = 75.0 },
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new() { Grade = "10", MinPercent = 70.0 },
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new() { Grade = "9", MinPercent = 65.0 },
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new() { Grade = "8", MinPercent = 60.0 },
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new() { Grade = "7", MinPercent = 55.0 },
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new() { Grade = "6", MinPercent = 50.0 },
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new() { Grade = "5", MinPercent = 45.0 },
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new() { Grade = "4", MinPercent = 40.0 },
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new() { Grade = "3", MinPercent = 33.0 },
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new() { Grade = "2", MinPercent = 27.0 },
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new() { Grade = "1", MinPercent = 20.0 },
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new() { Grade = "0", MinPercent = 0.0 },
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];
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public string? ValidateGradingKey(List<GradingKeyEntry> entries)
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{
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if (entries.Count < 2) return "Der Notenschlüssel braucht mindestens zwei Stufen.";
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if (entries.Any(e => string.IsNullOrWhiteSpace(e.Grade)))
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return "Jede Stufe braucht eine Bezeichnung.";
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if (entries.Any(e => e.MinPercent < 0 || e.MinPercent > 100))
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return "Prozentgrenzen müssen zwischen 0 und 100 liegen.";
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var sorted = entries.OrderByDescending(e => e.MinPercent).ToList();
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if (sorted.Select(e => e.MinPercent).Distinct().Count() != sorted.Count)
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return "Prozentgrenzen dürfen sich nicht doppeln.";
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if (sorted.Last().MinPercent != 0)
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return "Die unterste Stufe muss bei 0 % liegen (lückenlose Abdeckung).";
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return null;
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}
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/// Wandelt eine Mitarbeit-Bewertung im Bereich -2..+2 in eine Note/Punktzahl
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/// nach dem jeweiligen Notensystem der Gruppe um (0 % = -2, 100 % = +2).
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public string ParticipationGrade(double averageRating, GradingSystem system)
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{
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var percent = Math.Clamp((averageRating + 2.0) / 4.0 * 100.0, 0, 100);
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var key = system == GradingSystem.Points0To15 ? DefaultKey0To15() : DefaultKey1To6();
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return CalculateGrade(percent, 100, key);
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}
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public double WeightedAverage(List<(string Grade, double Weight)> grades)
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{
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var numeric = grades
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.Select(g => (Value: int.TryParse(g.Grade, out var n) ? (int?)n : null, g.Weight))
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.Where(g => g.Value.HasValue).ToList();
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if (numeric.Count == 0) return 0;
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var total = numeric.Sum(g => g.Weight);
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return total == 0 ? 0 : numeric.Sum(g => g.Value!.Value * g.Weight) / total;
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}
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}
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