fix: fix wrong date calculation

backend/handlers.go

@@ -4,6 +4,7 @@ import (
 	"database/sql"
 	"net/http"
 	"strconv"
+	"time"
 
 	"github.com/labstack/echo/v4"
 	"golang.org/x/crypto/bcrypt"
@@ -147,6 +148,44 @@ func (app *App) GetMyTimeEntriesHandler(c echo.Context) error {
 	return c.JSON(http.StatusOK, entries)
 }
 
+// GetWeekDates - Gibt die Daten einer Woche zurück (Montag-Freitag)
+func (app *App) GetWeekDates(c echo.Context) error {
+	year, err := strconv.Atoi(c.QueryParam("year"))
+	if err != nil {
+		return echo.NewHTTPError(http.StatusBadRequest, "Invalid year")
+	}
+
+	week, err := strconv.Atoi(c.QueryParam("week"))
+	if err != nil {
+		return echo.NewHTTPError(http.StatusBadRequest, "Invalid week")
+	}
+
+	dates := calculateWeekDates(year, week)
+	return c.JSON(http.StatusOK, dates)
+}
+
+// CheckWeekHasEntries - Prüft ob User Einträge für eine Woche hat
+func (app *App) CheckWeekHasEntries(c echo.Context) error {
+	userID := c.Get("user_id").(int)
+
+	year, err := strconv.Atoi(c.QueryParam("year"))
+	if err != nil {
+		return echo.NewHTTPError(http.StatusBadRequest, "Invalid year")
+	}
+
+	week, err := strconv.Atoi(c.QueryParam("week"))
+	if err != nil {
+		return echo.NewHTTPError(http.StatusBadRequest, "Invalid week")
+	}
+
+	hasEntries, err := CheckUserHasEntriesForWeek(app.DB, userID, year, week)
+	if err != nil {
+		return echo.NewHTTPError(http.StatusInternalServerError, err.Error())
+	}
+
+	return c.JSON(http.StatusOK, map[string]bool{"has_entries": hasEntries})
+}
+
 func (app *App) GetAllTimeEntriesHandler(c echo.Context) error {
 	entries, err := GetAllTimeEntries(app.DB)
 	if err != nil {
@@ -162,3 +201,72 @@ func (app *App) GetWeeklyHoursHandler(c echo.Context) error {
 	}
 	return c.JSON(http.StatusOK, hours)
 }
+
+func (app *App) DeleteWeekEntries(c echo.Context) error {
+	userID := c.Get("user_id").(int)
+
+	year, err := strconv.Atoi(c.QueryParam("year"))
+	if err != nil {
+		return echo.NewHTTPError(http.StatusBadRequest, "Invalid year")
+	}
+
+	week, err := strconv.Atoi(c.QueryParam("week"))
+	if err != nil {
+		return echo.NewHTTPError(http.StatusBadRequest, "Invalid week")
+	}
+
+	if err := DeleteTimeEntriesByUserAndWeek(app.DB, userID, year, week); err != nil {
+		return echo.NewHTTPError(http.StatusInternalServerError, err.Error())
+	}
+
+	return c.NoContent(http.StatusOK)
+}
+
+type WeekDates struct {
+	Year  int               `json:"year"`
+	Week  int               `json:"week"`
+	Dates map[string]string `json:"dates"` // dayOfWeek -> date
+	Range string            `json:"range"` // "2025-11-03 bis 2025-11-07"
+}
+
+func calculateWeekDates(year, week int) WeekDates {
+	// ISO 8601: Woche 1 ist die Woche mit dem ersten Donnerstag
+	// Finde den ersten Donnerstag des Jahres
+	jan4 := time.Date(year, time.January, 4, 0, 0, 0, 0, time.UTC)
+
+	// Finde Montag der Woche 1
+	weekday := int(jan4.Weekday())
+	if weekday == 0 {
+		weekday = 7 // Sonntag -> 7
+	}
+	daysToMonday := weekday - 1
+	mondayWeek1 := jan4.AddDate(0, 0, -daysToMonday)
+
+	// Berechne Montag der gewünschten Woche
+	targetMonday := mondayWeek1.AddDate(0, 0, (week-1)*7)
+
+	dates := make(map[string]string)
+	weekDays := []string{"0", "1", "2", "3", "4"} // Montag bis Freitag
+
+	var firstDate, lastDate time.Time
+	for i, day := range weekDays {
+		date := targetMonday.AddDate(0, 0, i)
+		dates[day] = date.Format("2006-01-02")
+
+		if i == 0 {
+			firstDate = date
+		}
+		if i == 4 {
+			lastDate = date
+		}
+	}
+
+	rangeStr := firstDate.Format("2006-01-02") + " bis " + lastDate.Format("2006-01-02")
+
+	return WeekDates{
+		Year:  year,
+		Week:  week,
+		Dates: dates,
+		Range: rangeStr,
+	}
+}