refactoring and documentation

service/fetch/fetchSeminarEventService.go

@@ -0,0 +1,270 @@
+package fetch
+
+import (
+	"fmt"
+	"github.com/labstack/echo/v5"
+	"github.com/pocketbase/pocketbase"
+	"github.com/pocketbase/pocketbase/apis"
+	"github.com/pocketbase/pocketbase/models"
+	"golang.org/x/net/html"
+	"htwk-planner/model"
+	"htwk-planner/service/date"
+	"htwk-planner/service/db"
+	"io"
+	"net/http"
+	"regexp"
+	"strconv"
+	"strings"
+	"time"
+)
+
+func GetSeminarEvents(c echo.Context, app *pocketbase.PocketBase) error {
+
+	seminarGroupsLabel := db.GetAllCourses(app)
+
+	seminarGroups := GetSeminarGroupsEventsFromHTML(seminarGroupsLabel)
+
+	collection, dbError := findCollection(app, "events")
+	if dbError != nil {
+		return apis.NewNotFoundError("Collection not found", dbError)
+	}
+
+	dbError = db.SaveEvents(seminarGroups, collection, app)
+	if dbError != nil {
+		return apis.NewApiError(400, "Could not save Event into database", dbError)
+	}
+
+	return c.JSON(http.StatusOK, seminarGroups)
+}
+
+func GetSeminarGroupsEventsFromHTML(seminarGroupsLabel []string) []model.SeminarGroup {
+	var seminarGroups []model.SeminarGroup
+	for _, seminarGroupLabel := range seminarGroupsLabel {
+
+		result, getError := getPlanHTML("ss", seminarGroupLabel)
+		if getError == nil {
+			seminarGroup := parseSeminarGroup(result)
+			seminarGroups = append(seminarGroups, seminarGroup)
+		}
+
+		result, getError = getPlanHTML("ws", seminarGroupLabel)
+		if getError == nil {
+			seminarGroup := parseSeminarGroup(result)
+			seminarGroups = append(seminarGroups, seminarGroup)
+		}
+	}
+	return seminarGroups
+}
+
+func findCollection(app *pocketbase.PocketBase, collectionName string) (*models.Collection, error) {
+	collection, dbError := app.Dao().FindCollectionByNameOrId(collectionName)
+	return collection, dbError
+}
+
+func parseSeminarGroup(result string) model.SeminarGroup {
+	doc, err := html.Parse(strings.NewReader(result))
+	if err != nil {
+		fmt.Printf("Error occurred while parsing the HTML document: %s\n", err.Error())
+		return model.SeminarGroup{}
+	}
+
+	table := findFirstTable(doc)
+	eventTables := getEventTables(doc)
+	allDayLabels := getAllDayLabels(doc)
+
+	if eventTables == nil || allDayLabels == nil {
+		return model.SeminarGroup{}
+	}
+
+	eventsWithCombinedWeeks := toEvents(eventTables, allDayLabels)
+	splitEventsByWeekVal := splitEventsByWeek(eventsWithCombinedWeeks)
+	events := splitEventsBySingleWeek(splitEventsByWeekVal)
+	semesterString := findFirstSpanWithClass(table, "header-0-2-0").FirstChild.Data
+	semester, year := extractSemesterAndYear(semesterString)
+	events = convertWeeksToDates(events, semester, year)
+	var seminarGroup = model.SeminarGroup{
+		University: findFirstSpanWithClass(table, "header-1-0-0").FirstChild.Data,
+		Course:     findFirstSpanWithClass(table, "header-2-0-1").FirstChild.Data,
+		Events:     events,
+	}
+	return seminarGroup
+}
+
+func convertWeeksToDates(events []model.Event, semester string, year string) []model.Event {
+	var newEvents []model.Event
+	eventYear, _ := strconv.Atoi(year)
+
+	// for each event we need to calculate the start and end date based on the week and the year
+	for _, event := range events {
+		eventWeek, _ := strconv.Atoi(event.Week)
+		eventDay, _ := date.GetDateFromWeekNumber(eventYear, eventWeek, event.Day)
+		start := addTimeToDate(eventDay, event.Start)
+		end := addTimeToDate(eventDay, event.End)
+		newEvent := event
+		newEvent.Start = start.String()
+		newEvent.End = end.String()
+		newEvent.Semester = semester
+		newEvents = append(newEvents, newEvent)
+	}
+	return newEvents
+}
+
+func addTimeToDate(date time.Time, timeString string) time.Time {
+	//convert time string to time
+	timeParts := strings.Split(timeString, ":")
+	hour, _ := strconv.Atoi(timeParts[0])
+	minute, _ := strconv.Atoi(timeParts[1])
+
+	return time.Date(date.Year(), date.Month(), date.Day(), hour, minute, 0, 0, time.UTC)
+}
+
+func extractSemesterAndYear(semesterString string) (string, string) {
+	winterPattern := "Wintersemester"
+	summerPattern := "Sommersemester"
+
+	winterMatch := strings.Contains(semesterString, winterPattern)
+	summerMatch := strings.Contains(semesterString, summerPattern)
+
+	semester := ""
+	semesterShortcut := ""
+
+	if winterMatch {
+		semester = "Wintersemester"
+		semesterShortcut = "ws"
+	} else if summerMatch {
+		semester = "Sommersemester"
+		semesterShortcut = "ss"
+	} else {
+		return "", ""
+	}
+
+	yearPattern := `\d{4}`
+	combinedPattern := semester + `\s` + yearPattern
+	re := regexp.MustCompile(combinedPattern)
+	match := re.FindString(semesterString)
+	year := ""
+
+	if match != "" {
+		reYear := regexp.MustCompile(yearPattern)
+		year = reYear.FindString(match)
+	}
+	return semesterShortcut, year
+}
+
+func toEvents(tables [][]*html.Node, days []string) []model.Event {
+	var events []model.Event
+
+	for table := range tables {
+		for row := range tables[table] {
+
+			tableData := findTableData(tables[table][row])
+			if len(tableData) > 0 {
+				events = append(events, model.Event{
+					Day:       days[table],
+					Week:      getTextContent(tableData[0]),
+					Start:     getTextContent(tableData[1]),
+					End:       getTextContent(tableData[2]),
+					Name:      getTextContent(tableData[3]),
+					EventType: getTextContent(tableData[4]),
+					Prof:      getTextContent(tableData[5]),
+					Rooms:     getTextContent(tableData[6]),
+					Notes:     getTextContent(tableData[7]),
+					BookedAt:  getTextContent(tableData[8]),
+				})
+			}
+		}
+
+	}
+
+	return events
+}
+
+func splitEventsByWeek(events []model.Event) []model.Event {
+	var newEvents []model.Event
+
+	for _, event := range events {
+		weeks := strings.Split(event.Week, ",")
+		for _, week := range weeks {
+			newEvent := event
+			newEvent.Week = strings.TrimSpace(week)
+			newEvents = append(newEvents, newEvent)
+		}
+	}
+	return newEvents
+}
+
+func splitEventsBySingleWeek(events []model.Event) []model.Event {
+	var newEvents []model.Event
+
+	for _, event := range events {
+		if strings.Contains(event.Week, "-") {
+			weeks := splitWeekRange(event.Week)
+			for _, week := range weeks {
+				newEvent := event
+				newEvent.Week = week
+				newEvents = append(newEvents, newEvent)
+			}
+		} else {
+			newEvents = append(newEvents, event)
+		}
+	}
+	return newEvents
+}
+
+func splitWeekRange(weekRange string) []string {
+	parts := strings.Split(weekRange, "-")
+	if len(parts) != 2 {
+		return nil // Invalid format
+	}
+
+	start, errStart := strconv.Atoi(strings.TrimSpace(parts[0]))
+	end, errEnd := strconv.Atoi(strings.TrimSpace(parts[1]))
+
+	if errStart != nil || errEnd != nil {
+		return nil // Error converting to integers
+	}
+
+	var weeks []string
+	for i := start; i <= end; i++ {
+		weeks = append(weeks, strconv.Itoa(i))
+	}
+
+	return weeks
+}
+
+func toUtf8(iso88591Buf []byte) string {
+	buf := make([]rune, len(iso88591Buf))
+	for i, b := range iso88591Buf {
+		buf[i] = rune(b)
+	}
+	return string(buf)
+}
+
+// getPlanHTML Get the HTML document from the specified URL
+func getPlanHTML(semester string, matrikel string) (string, error) {
+	url := "https://stundenplan.htwk-leipzig.de/" + string(semester) + "/Berichte/Text-Listen;Studenten-Sets;name;" + matrikel + "?template=sws_semgrp&weeks=1-65"
+
+	// Send GET request
+	response, err := http.Get(url)
+	if err != nil {
+		fmt.Printf("Error occurred while making the request: %s\n", err.Error())
+		return "", err
+	}
+	defer func(Body io.ReadCloser) {
+		err := Body.Close()
+		if err != nil {
+			return
+		}
+	}(response.Body)
+
+	// Read the response body
+	body, err := io.ReadAll(response.Body)
+
+	if err != nil {
+		fmt.Printf("Error occurred while reading the response: %s\n", err.Error())
+		return "", err
+	}
+
+	return toUtf8(body), err
+
+}