Add Noten parsing and rework some existing code

noten.go

@@ -1,10 +1,66 @@
 package lsf
 
 import (
+	"fmt"
+	"net/http"
+	"strings"
+
+	"github.com/PuerkitoBio/goquery"
 	"github.com/pkg/errors"
-	//"github.com/PuerkitoBio/goquery"
 )
 
-func (s *Session) Noten() (map[Modul]float32, error) {
-	return nil, errors.New("noten not implemented yet")
+// Note is a grade with associated data like the related module
+type Note struct {
+	Nr       string
+	Name     string
+	Semester string
+	Note     string
+	Status   string
+	CPs      string
+	Versuch  string
+}
+
+func (n *Note) String() string {
+	return fmt.Sprintf("%s: %s", n.Name, n.Note)
+}
+
+// Noten returns a list of the grades of all graded or signed up modules
+func (s *Session) Noten() ([]*Note, error) {
+	var noten []*Note
+	client := &http.Client{}
+	url := "https://lsf.hs-worms.de/qisserver/rds?state=notenspiegelStudent&next=list.vm&nextdir=qispos/notenspiegel/student&createInfos=Y&struct=auswahlBaum&nodeID=auswahlBaum%7Cabschluss%3Aabschl%3D05%2Cstgnr%3D1%7Cstudiengang%3Astg%3D938%2Cpversion%3D2018&expand=0&asi=" + s.ASI
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not prepare the request")
+	}
+	req.Header.Add("Cookie", fmt.Sprintf("JSESSIONID=%s", s.SID))
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not do the request")
+	}
+	doc, err := goquery.NewDocumentFromResponse(resp)
+	if err != nil {
+		return nil, err
+	}
+
+	// Find all tables. The last one contains the grades. Get all children rows.
+	rows := doc.Find("table").Last().Find("tr")
+	// The first three are the header, the average mark and a divider. So lets ignore them.
+	rows.Slice(3, rows.Length()).Each(func(_ int, row *goquery.Selection) {
+		vals := row.ChildrenFiltered("td").Map(func(i int, cell *goquery.Selection) string {
+			return strings.TrimSpace(cell.Text())
+		})
+		note := Note{
+			Nr:       vals[0],
+			Name:     vals[1],
+			Semester: vals[2],
+			Note:     vals[3],
+			Status:   vals[4],
+			CPs:      vals[5],
+			Versuch:  vals[7],
+		}
+		noten = append(noten, &note)
+	})
+
+	return noten, nil
 }