using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

namespace spplus;

public static class import
{
    public static List<Student> ImportStudentsFromFile(string path)
    {
        var dict = new Dictionary<string, (string Name, List<string> Courses)>();

        foreach (var line in File.ReadLines(path).Skip(1)) // Header überspringen
        {
            if (string.IsNullOrWhiteSpace(line))
                continue;

            var parts = line.Split(',');
            if (parts.Length < 3)
                continue;

            string nameWithId = parts[0].Trim();
            string course = parts[2].Replace("(2)", "").Replace("(3)", "").Replace("(4)", "").Trim();

            int open = nameWithId.LastIndexOf('(');
            int close = nameWithId.LastIndexOf(')');
            if (open < 0 || close < 0 || close <= open)
                continue;

            string name = nameWithId[..open].Trim();
            string id = nameWithId[(open + 1)..close].Trim();

            if (!dict.ContainsKey(id))
                dict[id] = (name, new List<string>());

            dict[id].Courses.Add(course);
        }

        var result = new List<Student>();

        foreach (var (id, data) in dict)
        {
            var student = new Student(id, data.Name, data.Courses);
            result.Add(student);
        }

        return result;
    }
}