91 lines
3.1 KiB
C#
91 lines
3.1 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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/// <summary>
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/// Berechnet die Note aus Punkten anhand des Notenschlüssels der Klausur.
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/// </summary>
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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
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.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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/// <summary>
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/// Standardnotenschlüssel 1–6 nach NRW-Schema (anpassbar).
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/// </summary>
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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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/// <summary>
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/// Standardnotenschlüssel 0–15 Punkte (Oberstufe).
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/// </summary>
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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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/// <summary>
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/// Berechnet den Notendurchschnitt aus einer Liste von Notenwerten (1-6 System).
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/// </summary>
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public double AverageGrade1To6(List<string> grades)
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{
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var numeric = grades
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.Select(g => int.TryParse(g, out var n) ? (int?)n : null)
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.Where(n => n.HasValue)
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.Select(n => n!.Value)
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.ToList();
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return numeric.Count == 0 ? 0 : numeric.Average();
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}
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/// <summary>
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/// Berechnet den Notendurchschnitt aus gewichteten Noten.
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/// </summary>
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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 => (
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Value: int.TryParse(g.Grade, out var n) ? (int?)n : null,
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g.Weight))
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.Where(g => g.Value.HasValue)
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.ToList();
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if (numeric.Count == 0) return 0;
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var totalWeight = numeric.Sum(g => g.Weight);
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var weightedSum = numeric.Sum(g => g.Value!.Value * g.Weight);
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return totalWeight == 0 ? 0 : weightedSum / totalWeight;
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}
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}
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