Add crop CRUD, owned fields, and field grouping for planning

cmd/server/main.go

@@ -27,9 +27,26 @@ type App struct {
 }
 
 type Field struct {
-	ID     int64
-	Number int
-	Name   string
+	ID        int64
+	Number    int
+	Name      string
+	Owned     bool
+	GroupKey  string
+	GroupName string
+}
+
+func (f Field) Label() string {
+	base := fmt.Sprintf("Feld %d", f.Number)
+	if f.Name != "" {
+		base += " (" + f.Name + ")"
+	}
+	return base
+}
+
+type FieldGroup struct {
+	Key     string
+	Name    string
+	Numbers string
 }
 
 type Crop struct {
@@ -42,9 +59,9 @@ type Crop struct {
 
 type Plan struct {
 	ID           int64
-	FieldID      int64
-	FieldNumber  int
-	FieldName    string
+	FieldID      sql.NullInt64
+	TargetRef    string
+	TargetName   string
 	CropID       int64
 	CropName     string
 	StartMonth   int
@@ -61,22 +78,29 @@ type Task struct {
 	SortOrder int
 }
 
+type PlanningTarget struct {
+	Ref   string
+	Label string
+}
+
 type MonthOption struct {
 	Value int
 	Label string
 }
 
 type PageData struct {
-	NowMonth     int
-	NowDay       int
-	DaysPerMonth int
-	Months       []MonthOption
-	Fields       []Field
-	Crops        []Crop
-	Plans        []Plan
-	Tasks        []Task
-	Error        string
-	Info         string
+	NowMonth        int
+	NowDay          int
+	DaysPerMonth    int
+	Months          []MonthOption
+	Fields          []Field
+	Groups          []FieldGroup
+	Crops           []Crop
+	Plans           []Plan
+	Tasks           []Task
+	PlanningTargets []PlanningTarget
+	Error           string
+	Info            string
 }
 
 func main() {
@@ -104,9 +128,16 @@ func main() {
 	app := &App{db: db, tmpl: tmpl}
 	mux := http.NewServeMux()
 	mux.HandleFunc("/", app.handleIndex)
-	mux.HandleFunc("/fields", app.handleCreateField)
-	mux.HandleFunc("/plans", app.handleCreatePlan)
 	mux.HandleFunc("/settings", app.handleSettings)
+	mux.HandleFunc("/fields/create", app.handleCreateField)
+	mux.HandleFunc("/fields/update", app.handleUpdateField)
+	mux.HandleFunc("/fields/delete", app.handleDeleteField)
+	mux.HandleFunc("/field-groups/create", app.handleCreateFieldGroup)
+	mux.HandleFunc("/field-groups/delete", app.handleDeleteFieldGroup)
+	mux.HandleFunc("/crops/create", app.handleCreateCrop)
+	mux.HandleFunc("/crops/update", app.handleUpdateCrop)
+	mux.HandleFunc("/crops/delete", app.handleDeleteCrop)
+	mux.HandleFunc("/plans/create", app.handleCreatePlan)
 	mux.Handle("/static/", http.StripPrefix("/static/", http.FileServer(http.Dir("static"))))
 
 	srv := &http.Server{
@@ -145,6 +176,8 @@ func (a *App) handleIndex(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "fields read failed", http.StatusInternalServerError)
 		return
 	}
+	groups := buildFieldGroups(fields)
+
 	crops, err := a.listCrops()
 	if err != nil {
 		http.Error(w, "crops read failed", http.StatusInternalServerError)
@@ -157,16 +190,18 @@ func (a *App) handleIndex(w http.ResponseWriter, r *http.Request) {
 	}
 
 	data := PageData{
-		NowMonth:     nowMonth,
-		NowDay:       nowDay,
-		DaysPerMonth: daysPerMonth,
-		Months:       monthOptions(),
-		Fields:       fields,
-		Crops:        crops,
-		Plans:        plans,
-		Tasks:        buildTasksForDay(plans, nowMonth, nowDay),
-		Error:        r.URL.Query().Get("error"),
-		Info:         r.URL.Query().Get("info"),
+		NowMonth:        nowMonth,
+		NowDay:          nowDay,
+		DaysPerMonth:    daysPerMonth,
+		Months:          monthOptions(),
+		Fields:          fields,
+		Groups:          groups,
+		Crops:           crops,
+		Plans:           plans,
+		Tasks:           buildTasksForDay(plans, nowMonth, nowDay),
+		PlanningTargets: buildPlanningTargets(fields),
+		Error:           r.URL.Query().Get("error"),
+		Info:            r.URL.Query().Get("info"),
 	}
 
 	if err := a.tmpl.Execute(w, data); err != nil {
@@ -174,104 +209,353 @@ func (a *App) handleIndex(w http.ResponseWriter, r *http.Request) {
 	}
 }
 
-func (a *App) handleCreateField(w http.ResponseWriter, r *http.Request) {
-	if r.Method != http.MethodPost {
-		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
-		return
-	}
-	if err := r.ParseForm(); err != nil {
-		http.Redirect(w, r, "/?error=form+ungueltig", http.StatusSeeOther)
-		return
-	}
-	number := mustInt(r.FormValue("number"), 0)
-	name := strings.TrimSpace(r.FormValue("name"))
-	if number <= 0 {
-		http.Redirect(w, r, "/?error=Feldnummer+ungueltig", http.StatusSeeOther)
-		return
-	}
-	if _, err := a.db.Exec(`INSERT INTO fields(number,name) VALUES (?,?)`, number, name); err != nil {
-		http.Redirect(w, r, "/?error=Feld+nicht+angelegt", http.StatusSeeOther)
-		return
-	}
-	http.Redirect(w, r, "/?info=Feld+angelegt", http.StatusSeeOther)
-}
-
-func (a *App) handleCreatePlan(w http.ResponseWriter, r *http.Request) {
-	if r.Method != http.MethodPost {
-		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
-		return
-	}
-	if err := r.ParseForm(); err != nil {
-		http.Redirect(w, r, "/?error=form+ungueltig", http.StatusSeeOther)
-		return
-	}
-
-	fieldID := mustInt64(r.FormValue("field_id"), 0)
-	cropID := mustInt64(r.FormValue("crop_id"), 0)
-	startMonth := mustInt(r.FormValue("start_month"), 1)
-	startDay := mustInt(r.FormValue("start_day"), 1)
-	notes := strings.TrimSpace(r.FormValue("notes"))
-
-	if fieldID <= 0 || cropID <= 0 {
-		http.Redirect(w, r, "/?error=Feld+oder+Frucht+ungueltig", http.StatusSeeOther)
-		return
-	}
-
-	daysPerMonth, err := a.getDaysPerMonth()
-	if err != nil {
-		http.Redirect(w, r, "/?error=Einstellungen+nicht+lesbar", http.StatusSeeOther)
-		return
-	}
-	if startMonth < 1 || startMonth > 12 || startDay < 1 || startDay > daysPerMonth {
-		http.Redirect(w, r, "/?error=Startdatum+ungueltig", http.StatusSeeOther)
-		return
-	}
-
-	var c Crop
-	err = a.db.QueryRow(`SELECT id,name,sow_start_month,sow_end_month,grow_months FROM crops WHERE id=?`, cropID).
-		Scan(&c.ID, &c.Name, &c.SowStartMonth, &c.SowEndMonth, &c.GrowMonths)
-	if err != nil {
-		http.Redirect(w, r, "/?error=Feldfrucht+nicht+gefunden", http.StatusSeeOther)
-		return
-	}
-
-	if !monthInWindow(startMonth, c.SowStartMonth, c.SowEndMonth) {
-		http.Redirect(w, r, "/?error=Aussaat+ausserhalb+des+Zeitfensters", http.StatusSeeOther)
-		return
-	}
-
-	harvestMonth := wrapMonth(startMonth + c.GrowMonths)
-	harvestDay := startDay
-	_, err = a.db.Exec(
-		`INSERT INTO plans(field_id,crop_id,start_month,start_day,harvest_month,harvest_day,notes) VALUES (?,?,?,?,?,?,?)`,
-		fieldID, cropID, startMonth, startDay, harvestMonth, harvestDay, notes,
-	)
-	if err != nil {
-		http.Redirect(w, r, "/?error=Plan+nicht+gespeichert", http.StatusSeeOther)
-		return
-	}
-	http.Redirect(w, r, "/?info=Plan+gespeichert", http.StatusSeeOther)
-}
-
 func (a *App) handleSettings(w http.ResponseWriter, r *http.Request) {
 	if r.Method != http.MethodPost {
 		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
 		return
 	}
 	if err := r.ParseForm(); err != nil {
-		http.Redirect(w, r, "/?error=form+ungueltig", http.StatusSeeOther)
+		redirectWithMessage(w, r, "error", "Form ungueltig")
 		return
 	}
 	daysPerMonth := mustInt(r.FormValue("days_per_month"), 2)
 	if daysPerMonth < 1 || daysPerMonth > 31 {
-		http.Redirect(w, r, "/?error=Tage+pro+Monat+1-31", http.StatusSeeOther)
+		redirectWithMessage(w, r, "error", "Tage pro Monat 1-31")
 		return
 	}
 	if _, err := a.db.Exec(`UPDATE settings SET days_per_month=? WHERE id=1`, daysPerMonth); err != nil {
-		http.Redirect(w, r, "/?error=Einstellungen+nicht+gespeichert", http.StatusSeeOther)
+		redirectWithMessage(w, r, "error", "Einstellungen nicht gespeichert")
 		return
 	}
-	http.Redirect(w, r, "/?info=Einstellungen+gespeichert", http.StatusSeeOther)
+	redirectWithMessage(w, r, "info", "Einstellungen gespeichert")
+}
+
+func (a *App) handleCreateField(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodPost {
+		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+	if err := r.ParseForm(); err != nil {
+		redirectWithMessage(w, r, "error", "Form ungueltig")
+		return
+	}
+	number := mustInt(r.FormValue("number"), 0)
+	name := strings.TrimSpace(r.FormValue("name"))
+	owned := r.FormValue("owned") == "on"
+	if number <= 0 {
+		redirectWithMessage(w, r, "error", "Feldnummer ungueltig")
+		return
+	}
+	if _, err := a.db.Exec(`INSERT INTO fields(number,name,owned) VALUES (?,?,?)`, number, name, owned); err != nil {
+		redirectWithMessage(w, r, "error", "Feld nicht angelegt (Nummer evtl. schon vorhanden)")
+		return
+	}
+	redirectWithMessage(w, r, "info", "Feld angelegt")
+}
+
+func (a *App) handleUpdateField(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodPost {
+		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+	if err := r.ParseForm(); err != nil {
+		redirectWithMessage(w, r, "error", "Form ungueltig")
+		return
+	}
+	id := mustInt64(r.FormValue("id"), 0)
+	name := strings.TrimSpace(r.FormValue("name"))
+	owned := r.FormValue("owned") == "on"
+	if id <= 0 {
+		redirectWithMessage(w, r, "error", "Feld-ID ungueltig")
+		return
+	}
+
+	if owned {
+		if _, err := a.db.Exec(`UPDATE fields SET name=?,owned=? WHERE id=?`, name, owned, id); err != nil {
+			redirectWithMessage(w, r, "error", "Feld nicht aktualisiert")
+			return
+		}
+	} else {
+		if _, err := a.db.Exec(`UPDATE fields SET name=?,owned=?,group_key='',group_name='' WHERE id=?`, name, owned, id); err != nil {
+			redirectWithMessage(w, r, "error", "Feld nicht aktualisiert")
+			return
+		}
+	}
+	redirectWithMessage(w, r, "info", "Feld aktualisiert")
+}
+
+func (a *App) handleDeleteField(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodPost {
+		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+	if err := r.ParseForm(); err != nil {
+		redirectWithMessage(w, r, "error", "Form ungueltig")
+		return
+	}
+	id := mustInt64(r.FormValue("id"), 0)
+	if id <= 0 {
+		redirectWithMessage(w, r, "error", "Feld-ID ungueltig")
+		return
+	}
+	if _, err := a.db.Exec(`DELETE FROM fields WHERE id=?`, id); err != nil {
+		redirectWithMessage(w, r, "error", "Feld nicht geloescht")
+		return
+	}
+	redirectWithMessage(w, r, "info", "Feld geloescht")
+}
+
+func (a *App) handleCreateFieldGroup(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodPost {
+		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+	if err := r.ParseForm(); err != nil {
+		redirectWithMessage(w, r, "error", "Form ungueltig")
+		return
+	}
+	ids, err := parseInt64List(r.Form["field_ids"])
+	if err != nil || len(ids) == 0 {
+		redirectWithMessage(w, r, "error", "Mindestens ein Feld auswaehlen")
+		return
+	}
+
+	fields, err := a.getFieldsByIDs(ids)
+	if err != nil || len(fields) != len(ids) {
+		redirectWithMessage(w, r, "error", "Felder nicht eindeutig gefunden")
+		return
+	}
+
+	groupName := strings.TrimSpace(r.FormValue("name"))
+	if groupName == "" {
+		groupName = autoGroupName(fields)
+	}
+	groupKey := fmt.Sprintf("g%d", time.Now().UnixNano())
+
+	tx, err := a.db.Begin()
+	if err != nil {
+		redirectWithMessage(w, r, "error", "Gruppierung fehlgeschlagen")
+		return
+	}
+	defer tx.Rollback()
+
+	for _, f := range fields {
+		if _, err := tx.Exec(`UPDATE fields SET group_key=?,group_name=? WHERE id=?`, groupKey, groupName, f.ID); err != nil {
+			redirectWithMessage(w, r, "error", "Gruppierung fehlgeschlagen")
+			return
+		}
+	}
+	if err := tx.Commit(); err != nil {
+		redirectWithMessage(w, r, "error", "Gruppierung fehlgeschlagen")
+		return
+	}
+	redirectWithMessage(w, r, "info", "Feldgruppe gespeichert")
+}
+
+func (a *App) handleDeleteFieldGroup(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodPost {
+		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+	if err := r.ParseForm(); err != nil {
+		redirectWithMessage(w, r, "error", "Form ungueltig")
+		return
+	}
+	key := strings.TrimSpace(r.FormValue("group_key"))
+	if key == "" {
+		redirectWithMessage(w, r, "error", "Gruppen-ID ungueltig")
+		return
+	}
+	if _, err := a.db.Exec(`UPDATE fields SET group_key='',group_name='' WHERE group_key=?`, key); err != nil {
+		redirectWithMessage(w, r, "error", "Gruppe nicht aufgeloest")
+		return
+	}
+	redirectWithMessage(w, r, "info", "Gruppe aufgeloest")
+}
+
+func (a *App) handleCreateCrop(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodPost {
+		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+	if err := r.ParseForm(); err != nil {
+		redirectWithMessage(w, r, "error", "Form ungueltig")
+		return
+	}
+	name := strings.TrimSpace(r.FormValue("name"))
+	start := mustInt(r.FormValue("sow_start_month"), 0)
+	end := mustInt(r.FormValue("sow_end_month"), 0)
+	grow := mustInt(r.FormValue("grow_months"), 0)
+	if err := validateCropInput(name, start, end, grow); err != nil {
+		redirectWithMessage(w, r, "error", err.Error())
+		return
+	}
+	if _, err := a.db.Exec(`INSERT INTO crops(name,sow_start_month,sow_end_month,grow_months) VALUES (?,?,?,?)`, name, start, end, grow); err != nil {
+		redirectWithMessage(w, r, "error", "Feldfrucht nicht angelegt")
+		return
+	}
+	redirectWithMessage(w, r, "info", "Feldfrucht angelegt")
+}
+
+func (a *App) handleUpdateCrop(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodPost {
+		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+	if err := r.ParseForm(); err != nil {
+		redirectWithMessage(w, r, "error", "Form ungueltig")
+		return
+	}
+	id := mustInt64(r.FormValue("id"), 0)
+	name := strings.TrimSpace(r.FormValue("name"))
+	start := mustInt(r.FormValue("sow_start_month"), 0)
+	end := mustInt(r.FormValue("sow_end_month"), 0)
+	grow := mustInt(r.FormValue("grow_months"), 0)
+	if id <= 0 {
+		redirectWithMessage(w, r, "error", "Feldfrucht-ID ungueltig")
+		return
+	}
+	if err := validateCropInput(name, start, end, grow); err != nil {
+		redirectWithMessage(w, r, "error", err.Error())
+		return
+	}
+	if _, err := a.db.Exec(`UPDATE crops SET name=?,sow_start_month=?,sow_end_month=?,grow_months=? WHERE id=?`, name, start, end, grow, id); err != nil {
+		redirectWithMessage(w, r, "error", "Feldfrucht nicht aktualisiert")
+		return
+	}
+	redirectWithMessage(w, r, "info", "Feldfrucht aktualisiert")
+}
+
+func (a *App) handleDeleteCrop(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodPost {
+		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+	if err := r.ParseForm(); err != nil {
+		redirectWithMessage(w, r, "error", "Form ungueltig")
+		return
+	}
+	id := mustInt64(r.FormValue("id"), 0)
+	if id <= 0 {
+		redirectWithMessage(w, r, "error", "Feldfrucht-ID ungueltig")
+		return
+	}
+	if _, err := a.db.Exec(`DELETE FROM crops WHERE id=?`, id); err != nil {
+		redirectWithMessage(w, r, "error", "Feldfrucht nicht geloescht (ggf. in Verwendung)")
+		return
+	}
+	redirectWithMessage(w, r, "info", "Feldfrucht geloescht")
+}
+
+func (a *App) handleCreatePlan(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodPost {
+		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+	if err := r.ParseForm(); err != nil {
+		redirectWithMessage(w, r, "error", "Form ungueltig")
+		return
+	}
+
+	targetRef := strings.TrimSpace(r.FormValue("target_ref"))
+	cropID := mustInt64(r.FormValue("crop_id"), 0)
+	startMonth := mustInt(r.FormValue("start_month"), 1)
+	startDay := mustInt(r.FormValue("start_day"), 1)
+	notes := strings.TrimSpace(r.FormValue("notes"))
+	if targetRef == "" || cropID <= 0 {
+		redirectWithMessage(w, r, "error", "Ziel oder Feldfrucht ungueltig")
+		return
+	}
+
+	daysPerMonth, err := a.getDaysPerMonth()
+	if err != nil {
+		redirectWithMessage(w, r, "error", "Einstellungen nicht lesbar")
+		return
+	}
+	if startMonth < 1 || startMonth > 12 || startDay < 1 || startDay > daysPerMonth {
+		redirectWithMessage(w, r, "error", "Startdatum ungueltig")
+		return
+	}
+
+	var c Crop
+	err = a.db.QueryRow(`SELECT id,name,sow_start_month,sow_end_month,grow_months FROM crops WHERE id=?`, cropID).
+		Scan(&c.ID, &c.Name, &c.SowStartMonth, &c.SowEndMonth, &c.GrowMonths)
+	if err != nil {
+		redirectWithMessage(w, r, "error", "Feldfrucht nicht gefunden")
+		return
+	}
+	if !monthInWindow(startMonth, c.SowStartMonth, c.SowEndMonth) {
+		redirectWithMessage(w, r, "error", "Aussaat ausserhalb des Zeitfensters")
+		return
+	}
+
+	fieldID, targetName, err := a.resolvePlanningTarget(targetRef)
+	if err != nil {
+		redirectWithMessage(w, r, "error", err.Error())
+		return
+	}
+
+	harvestMonth := wrapMonth(startMonth + c.GrowMonths)
+	harvestDay := startDay
+	_, err = a.db.Exec(
+		`INSERT INTO plans(field_id,target_ref,target_name,crop_id,start_month,start_day,harvest_month,harvest_day,notes) VALUES (?,?,?,?,?,?,?,?,?)`,
+		fieldID, targetRef, targetName, cropID, startMonth, startDay, harvestMonth, harvestDay, notes,
+	)
+	if err != nil {
+		redirectWithMessage(w, r, "error", "Plan nicht gespeichert")
+		return
+	}
+	redirectWithMessage(w, r, "info", "Plan gespeichert")
+}
+
+func (a *App) resolvePlanningTarget(ref string) (sql.NullInt64, string, error) {
+	if strings.HasPrefix(ref, "f:") {
+		id := mustInt64(strings.TrimPrefix(ref, "f:"), 0)
+		if id <= 0 {
+			return sql.NullInt64{}, "", errors.New("Feld-Ziel ungueltig")
+		}
+		var f Field
+		err := a.db.QueryRow(`SELECT id,number,name,owned FROM fields WHERE id=?`, id).
+			Scan(&f.ID, &f.Number, &f.Name, &f.Owned)
+		if err != nil {
+			return sql.NullInt64{}, "", errors.New("Feld nicht gefunden")
+		}
+		if !f.Owned {
+			return sql.NullInt64{}, "", errors.New("Feld ist nicht im Besitz")
+		}
+		return sql.NullInt64{Int64: f.ID, Valid: true}, f.Label(), nil
+	}
+
+	if strings.HasPrefix(ref, "g:") {
+		groupKey := strings.TrimPrefix(ref, "g:")
+		if groupKey == "" {
+			return sql.NullInt64{}, "", errors.New("Gruppen-Ziel ungueltig")
+		}
+		rows, err := a.db.Query(`SELECT number FROM fields WHERE group_key=? AND owned=1 ORDER BY number`, groupKey)
+		if err != nil {
+			return sql.NullInt64{}, "", errors.New("Gruppe nicht lesbar")
+		}
+		defer rows.Close()
+		var nums []string
+		for rows.Next() {
+			var n int
+			if err := rows.Scan(&n); err != nil {
+				return sql.NullInt64{}, "", errors.New("Gruppe nicht lesbar")
+			}
+			nums = append(nums, strconv.Itoa(n))
+		}
+		if len(nums) == 0 {
+			return sql.NullInt64{}, "", errors.New("Gruppe hat keine Felder im Besitz")
+		}
+		var groupName string
+		_ = a.db.QueryRow(`SELECT COALESCE(group_name,'') FROM fields WHERE group_key=? LIMIT 1`, groupKey).Scan(&groupName)
+		if strings.TrimSpace(groupName) == "" {
+			groupName = "Feld " + strings.Join(nums, "+")
+		}
+		return sql.NullInt64{}, groupName, nil
+	}
+
+	return sql.NullInt64{}, "", errors.New("Planungsziel ungueltig")
 }
 
 func (a *App) getDaysPerMonth() (int, error) {
@@ -281,7 +565,7 @@ func (a *App) getDaysPerMonth() (int, error) {
 }
 
 func (a *App) listFields() ([]Field, error) {
-	rows, err := a.db.Query(`SELECT id,number,name FROM fields ORDER BY number`)
+	rows, err := a.db.Query(`SELECT id,number,name,owned,COALESCE(group_key,''),COALESCE(group_name,'') FROM fields ORDER BY number`)
 	if err != nil {
 		return nil, err
 	}
@@ -289,7 +573,37 @@ func (a *App) listFields() ([]Field, error) {
 	var out []Field
 	for rows.Next() {
 		var x Field
-		if err := rows.Scan(&x.ID, &x.Number, &x.Name); err != nil {
+		if err := rows.Scan(&x.ID, &x.Number, &x.Name, &x.Owned, &x.GroupKey, &x.GroupName); err != nil {
+			return nil, err
+		}
+		out = append(out, x)
+	}
+	return out, rows.Err()
+}
+
+func (a *App) getFieldsByIDs(ids []int64) ([]Field, error) {
+	if len(ids) == 0 {
+		return nil, nil
+	}
+	ph := placeholders(len(ids))
+	args := make([]any, 0, len(ids))
+	for _, id := range ids {
+		args = append(args, id)
+	}
+
+	rows, err := a.db.Query(
+		fmt.Sprintf(`SELECT id,number,name,owned,COALESCE(group_key,''),COALESCE(group_name,'') FROM fields WHERE id IN (%s)`, ph),
+		args...,
+	)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var out []Field
+	for rows.Next() {
+		var x Field
+		if err := rows.Scan(&x.ID, &x.Number, &x.Name, &x.Owned, &x.GroupKey, &x.GroupName); err != nil {
 			return nil, err
 		}
 		out = append(out, x)
@@ -316,11 +630,10 @@ func (a *App) listCrops() ([]Crop, error) {
 
 func (a *App) listPlans() ([]Plan, error) {
 	rows, err := a.db.Query(`
-		SELECT p.id,p.field_id,f.number,COALESCE(f.name,''),p.crop_id,c.name,p.start_month,p.start_day,p.harvest_month,p.harvest_day,COALESCE(p.notes,'')
+		SELECT p.id,p.field_id,COALESCE(p.target_ref,''),COALESCE(p.target_name,''),p.crop_id,COALESCE(c.name,''),p.start_month,p.start_day,p.harvest_month,p.harvest_day,COALESCE(p.notes,'')
 		FROM plans p
-		JOIN fields f ON f.id=p.field_id
 		JOIN crops c ON c.id=p.crop_id
-		ORDER BY p.start_month,p.start_day,f.number`)
+		ORDER BY p.start_month,p.start_day,p.id DESC`)
 	if err != nil {
 		return nil, err
 	}
@@ -328,7 +641,7 @@ func (a *App) listPlans() ([]Plan, error) {
 	var out []Plan
 	for rows.Next() {
 		var x Plan
-		if err := rows.Scan(&x.ID, &x.FieldID, &x.FieldNumber, &x.FieldName, &x.CropID, &x.CropName, &x.StartMonth, &x.StartDay, &x.HarvestMonth, &x.HarvestDay, &x.Notes); err != nil {
+		if err := rows.Scan(&x.ID, &x.FieldID, &x.TargetRef, &x.TargetName, &x.CropID, &x.CropName, &x.StartMonth, &x.StartDay, &x.HarvestMonth, &x.HarvestDay, &x.Notes); err != nil {
 			return nil, err
 		}
 		out = append(out, x)
@@ -340,15 +653,54 @@ func ensureSchema(db *sql.DB) error {
 	stmts := []string{
 		`CREATE TABLE IF NOT EXISTS settings(id TINYINT PRIMARY KEY,days_per_month INT NOT NULL DEFAULT 2)`,
 		`INSERT INTO settings(id,days_per_month) VALUES (1,2) ON DUPLICATE KEY UPDATE id=id`,
-		`CREATE TABLE IF NOT EXISTS fields(id BIGINT AUTO_INCREMENT PRIMARY KEY,number INT NOT NULL UNIQUE,name VARCHAR(120) NOT NULL DEFAULT '',created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP)`,
-		`CREATE TABLE IF NOT EXISTS crops(id BIGINT AUTO_INCREMENT PRIMARY KEY,name VARCHAR(80) NOT NULL UNIQUE,sow_start_month TINYINT NOT NULL,sow_end_month TINYINT NOT NULL,grow_months TINYINT NOT NULL)`,
-		`CREATE TABLE IF NOT EXISTS plans(id BIGINT AUTO_INCREMENT PRIMARY KEY,field_id BIGINT NOT NULL,crop_id BIGINT NOT NULL,start_month TINYINT NOT NULL,start_day TINYINT NOT NULL,harvest_month TINYINT NOT NULL,harvest_day TINYINT NOT NULL,notes VARCHAR(255) NOT NULL DEFAULT '',created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,CONSTRAINT fk_plans_fields FOREIGN KEY(field_id) REFERENCES fields(id) ON DELETE CASCADE,CONSTRAINT fk_plans_crops FOREIGN KEY(crop_id) REFERENCES crops(id) ON DELETE RESTRICT)`,
+
+		`CREATE TABLE IF NOT EXISTS fields(
+			id BIGINT AUTO_INCREMENT PRIMARY KEY,
+			number INT NOT NULL UNIQUE,
+			name VARCHAR(120) NOT NULL DEFAULT '',
+			owned TINYINT(1) NOT NULL DEFAULT 0,
+			group_key VARCHAR(64) NOT NULL DEFAULT '',
+			group_name VARCHAR(120) NOT NULL DEFAULT '',
+			created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
+		)`,
+		`ALTER TABLE fields ADD COLUMN IF NOT EXISTS owned TINYINT(1) NOT NULL DEFAULT 0`,
+		`ALTER TABLE fields ADD COLUMN IF NOT EXISTS group_key VARCHAR(64) NOT NULL DEFAULT ''`,
+		`ALTER TABLE fields ADD COLUMN IF NOT EXISTS group_name VARCHAR(120) NOT NULL DEFAULT ''`,
+
+		`CREATE TABLE IF NOT EXISTS crops(
+			id BIGINT AUTO_INCREMENT PRIMARY KEY,
+			name VARCHAR(80) NOT NULL UNIQUE,
+			sow_start_month TINYINT NOT NULL,
+			sow_end_month TINYINT NOT NULL,
+			grow_months TINYINT NOT NULL
+		)`,
+
+		`CREATE TABLE IF NOT EXISTS plans(
+			id BIGINT AUTO_INCREMENT PRIMARY KEY,
+			field_id BIGINT NULL,
+			target_ref VARCHAR(80) NOT NULL DEFAULT '',
+			target_name VARCHAR(140) NOT NULL DEFAULT '',
+			crop_id BIGINT NOT NULL,
+			start_month TINYINT NOT NULL,
+			start_day TINYINT NOT NULL,
+			harvest_month TINYINT NOT NULL,
+			harvest_day TINYINT NOT NULL,
+			notes VARCHAR(255) NOT NULL DEFAULT '',
+			created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+			CONSTRAINT fk_plans_fields FOREIGN KEY(field_id) REFERENCES fields(id) ON DELETE CASCADE,
+			CONSTRAINT fk_plans_crops FOREIGN KEY(crop_id) REFERENCES crops(id) ON DELETE RESTRICT
+		)`,
+		`ALTER TABLE plans MODIFY COLUMN field_id BIGINT NULL`,
+		`ALTER TABLE plans ADD COLUMN IF NOT EXISTS target_ref VARCHAR(80) NOT NULL DEFAULT '' AFTER field_id`,
+		`ALTER TABLE plans ADD COLUMN IF NOT EXISTS target_name VARCHAR(140) NOT NULL DEFAULT '' AFTER target_ref`,
 	}
+
 	for _, stmt := range stmts {
 		if _, err := db.Exec(stmt); err != nil {
 			return err
 		}
 	}
+
 	return seedCrops(db)
 }
 
@@ -374,12 +726,91 @@ func seedCrops(db *sql.DB) error {
 	return nil
 }
 
+func buildPlanningTargets(fields []Field) []PlanningTarget {
+	groupMap := make(map[string][]Field)
+	var out []PlanningTarget
+
+	for _, f := range fields {
+		if !f.Owned {
+			continue
+		}
+		if f.GroupKey == "" {
+			out = append(out, PlanningTarget{
+				Ref:   fmt.Sprintf("f:%d", f.ID),
+				Label: f.Label(),
+			})
+			continue
+		}
+		groupMap[f.GroupKey] = append(groupMap[f.GroupKey], f)
+	}
+
+	groupKeys := make([]string, 0, len(groupMap))
+	for k := range groupMap {
+		groupKeys = append(groupKeys, k)
+	}
+	sort.Strings(groupKeys)
+	for _, k := range groupKeys {
+		members := groupMap[k]
+		sort.Slice(members, func(i, j int) bool { return members[i].Number < members[j].Number })
+		label := members[0].GroupName
+		if strings.TrimSpace(label) == "" {
+			label = autoGroupName(members)
+		}
+		out = append(out, PlanningTarget{
+			Ref:   "g:" + k,
+			Label: label,
+		})
+	}
+
+	sort.Slice(out, func(i, j int) bool { return out[i].Label < out[j].Label })
+	return out
+}
+
+func buildFieldGroups(fields []Field) []FieldGroup {
+	groupMap := make(map[string][]Field)
+	for _, f := range fields {
+		if f.GroupKey == "" {
+			continue
+		}
+		groupMap[f.GroupKey] = append(groupMap[f.GroupKey], f)
+	}
+
+	var out []FieldGroup
+	for k, members := range groupMap {
+		sort.Slice(members, func(i, j int) bool { return members[i].Number < members[j].Number })
+		nums := make([]string, 0, len(members))
+		for _, m := range members {
+			nums = append(nums, strconv.Itoa(m.Number))
+		}
+		name := members[0].GroupName
+		if strings.TrimSpace(name) == "" {
+			name = autoGroupName(members)
+		}
+		out = append(out, FieldGroup{
+			Key:     k,
+			Name:    name,
+			Numbers: strings.Join(nums, "+"),
+		})
+	}
+	sort.Slice(out, func(i, j int) bool { return out[i].Name < out[j].Name })
+	return out
+}
+
+func autoGroupName(fields []Field) string {
+	sort.Slice(fields, func(i, j int) bool { return fields[i].Number < fields[j].Number })
+	parts := make([]string, 0, len(fields))
+	for _, f := range fields {
+		parts = append(parts, strconv.Itoa(f.Number))
+	}
+	return "Feld " + strings.Join(parts, "+")
+}
+
 func buildTasksForDay(plans []Plan, month, day int) []Task {
 	var tasks []Task
 	for _, p := range plans {
-		field := fmt.Sprintf("Feld %d", p.FieldNumber)
-		if p.FieldName != "" {
-			field = fmt.Sprintf("Feld %d (%s)", p.FieldNumber, p.FieldName)
+		field := p.TargetName
+		if strings.TrimSpace(field) == "" {
+			field = "Unbekanntes Feld"
 		}
 		if p.StartMonth == month && p.StartDay == day {
 			tasks = append(tasks, Task{Type: "Aussaat", Field: field, Message: fmt.Sprintf("%s auf %s aussaeen", p.CropName, field), SortOrder: 1})
@@ -405,6 +836,19 @@ func monthOptions() []MonthOption {
 	return out
 }
 
+func validateCropInput(name string, start, end, grow int) error {
+	if name == "" {
+		return errors.New("Name der Feldfrucht fehlt")
+	}
+	if start < 1 || start > 12 || end < 1 || end > 12 {
+		return errors.New("Aussaatmonat muss 1-12 sein")
+	}
+	if grow < 1 || grow > 24 {
+		return errors.New("Wachstumsdauer muss 1-24 sein")
+	}
+	return nil
+}
+
 func monthInWindow(month, start, end int) bool {
 	if start <= end {
 		return month >= start && month <= end
@@ -420,6 +864,34 @@ func wrapMonth(v int) int {
 	return m
 }
 
+func placeholders(n int) string {
+	if n <= 0 {
+		return ""
+	}
+	parts := make([]string, 0, n)
+	for i := 0; i < n; i++ {
+		parts = append(parts, "?")
+	}
+	return strings.Join(parts, ",")
+}
+
+func parseInt64List(values []string) ([]int64, error) {
+	var out []int64
+	for _, v := range values {
+		id := mustInt64(v, 0)
+		if id <= 0 {
+			return nil, errors.New("invalid id")
+		}
+		out = append(out, id)
+	}
+	return out, nil
+}
+
+func redirectWithMessage(w http.ResponseWriter, r *http.Request, key, value string) {
+	target := fmt.Sprintf("/?%s=%s", key, strings.ReplaceAll(value, " ", "+"))
+	http.Redirect(w, r, target, http.StatusSeeOther)
+}
+
 func mustInt(v string, fallback int) int {
 	n, err := strconv.Atoi(strings.TrimSpace(v))
 	if err != nil {

static/styles.css

@@ -73,6 +73,36 @@ button {
   font-weight: 700;
 }
 button:hover { background: #2d5124; }
+.btn-small { padding: .4rem .6rem; font-size: .9rem; }
+.danger { background: #a13939; }
+.danger:hover { background: #8f2f2f; }
+
+.check {
+  display: inline-flex;
+  align-items: center;
+  gap: .45rem;
+}
+.check input { width: 1rem; height: 1rem; }
+
+.hint {
+  color: var(--muted);
+  font-size: .9rem;
+}
+
+.actions {
+  display: flex;
+  gap: .45rem;
+  align-items: center;
+}
+
+.inline-inputs {
+  display: inline-flex;
+  gap: .35rem;
+  align-items: center;
+}
+.inline-inputs input {
+  width: 5rem;
+}
 
 .tasks {
   margin: 0;

templates/index.html

@@ -9,7 +9,7 @@
 <body>
   <header class="top">
     <h1>FarmCal</h1>
-    <p>Planung fuer Felder, Aussaat und Ernte</p>
+    <p>Planung fuer Felder, Feldgruppen, Aussaat und Ernte</p>
   </header>
 
   <main class="layout">
@@ -28,7 +28,6 @@
         </label>
         <button type="submit">Anzeigen</button>
       </form>
-
       <form method="post" action="/settings" class="grid mt">
         <label>Tage pro Monat
           <input type="number" name="days_per_month" min="1" max="31" value="{{.DaysPerMonth}}">
@@ -42,9 +41,7 @@
       {{if .Tasks}}
       <ul class="tasks">
         {{range .Tasks}}
-        <li>
-          <strong>{{.Type}}:</strong> {{.Message}}
-        </li>
+        <li><strong>{{.Type}}:</strong> {{.Message}}</li>
         {{end}}
       </ul>
       {{else}}
@@ -53,39 +50,197 @@
     </section>
 
     <section class="card">
-      <h2>Feld anlegen</h2>
-      <form method="post" action="/fields" class="grid">
+      <h2>Felder verwalten</h2>
+      <form method="post" action="/fields/create" class="grid">
         <label>Feldnummer
           <input type="number" name="number" min="1" required>
         </label>
         <label>Name (optional)
           <input type="text" name="name" maxlength="120">
         </label>
-        <button type="submit">Feld speichern</button>
+        <label class="check">
+          <input type="checkbox" name="owned">
+          Im Besitz
+        </label>
+        <button type="submit">Feld anlegen</button>
       </form>
+
+      <div class="table-wrap mt">
+        <table>
+          <thead>
+            <tr>
+              <th>Nummer</th>
+              <th>Name</th>
+              <th>Besitz</th>
+              <th>Gruppe</th>
+              <th>Aktionen</th>
+            </tr>
+          </thead>
+          <tbody>
+            {{if .Fields}}
+              {{range .Fields}}
+              <tr>
+                <form method="post" action="/fields/update">
+                  <td>
+                    Feld {{.Number}}
+                    <input type="hidden" name="id" value="{{.ID}}">
+                  </td>
+                  <td><input type="text" name="name" value="{{.Name}}" maxlength="120"></td>
+                  <td>
+                    <label class="check">
+                      <input type="checkbox" name="owned" {{if .Owned}}checked{{end}}>
+                      Im Besitz
+                    </label>
+                  </td>
+                  <td>{{if .GroupName}}{{.GroupName}}{{else}}-{{end}}</td>
+                  <td class="actions">
+                    <button type="submit" class="btn-small">Speichern</button>
+                </form>
+                <form method="post" action="/fields/delete" onsubmit="return confirm('Feld wirklich loeschen?');">
+                  <input type="hidden" name="id" value="{{.ID}}">
+                  <button type="submit" class="btn-small danger">Loeschen</button>
+                </form>
+                  </td>
+              </tr>
+              {{end}}
+            {{else}}
+              <tr><td colspan="5">Noch keine Felder vorhanden.</td></tr>
+            {{end}}
+          </tbody>
+        </table>
+      </div>
     </section>
 
     <section class="card">
-      <h2>Anbau planen</h2>
-      <form method="post" action="/plans" class="grid">
-        <label>Feld
-          <select name="field_id" required>
-            <option value="">Bitte waehlen</option>
+      <h2>Feldgruppen</h2>
+      <form method="post" action="/field-groups/create" class="grid">
+        <label class="full">Name (optional)
+          <input type="text" name="name" maxlength="120" placeholder="z.B. Feld 1+2">
+        </label>
+        <label class="full">Felder (1 bis X)
+          <select name="field_ids" multiple size="6">
             {{range .Fields}}
             <option value="{{.ID}}">Feld {{.Number}}{{if .Name}} ({{.Name}}){{end}}</option>
             {{end}}
           </select>
         </label>
+        <button type="submit">Gruppe speichern</button>
+      </form>
+      <p class="hint">Mehrfachauswahl: mit Strg/Cmd klicken.</p>
 
+      <div class="table-wrap mt">
+        <table>
+          <thead>
+            <tr>
+              <th>Name</th>
+              <th>Felder</th>
+              <th>Aktion</th>
+            </tr>
+          </thead>
+          <tbody>
+            {{if .Groups}}
+              {{range .Groups}}
+              <tr>
+                <td>{{.Name}}</td>
+                <td>{{.Numbers}}</td>
+                <td>
+                  <form method="post" action="/field-groups/delete" onsubmit="return confirm('Gruppe aufloesen?');">
+                    <input type="hidden" name="group_key" value="{{.Key}}">
+                    <button type="submit" class="btn-small danger">Aufloesen</button>
+                  </form>
+                </td>
+              </tr>
+              {{end}}
+            {{else}}
+              <tr><td colspan="3">Noch keine Feldgruppen vorhanden.</td></tr>
+            {{end}}
+          </tbody>
+        </table>
+      </div>
+    </section>
+
+    <section class="card">
+      <h2>Feldfruechte verwalten</h2>
+      <form method="post" action="/crops/create" class="grid">
+        <label>Name
+          <input type="text" name="name" maxlength="80" required>
+        </label>
+        <label>Aussaat von (Monat)
+          <input type="number" name="sow_start_month" min="1" max="12" required>
+        </label>
+        <label>Aussaat bis (Monat)
+          <input type="number" name="sow_end_month" min="1" max="12" required>
+        </label>
+        <label>Wachstum (Monate)
+          <input type="number" name="grow_months" min="1" max="24" required>
+        </label>
+        <button type="submit">Feldfrucht anlegen</button>
+      </form>
+
+      <div class="table-wrap mt">
+        <table>
+          <thead>
+            <tr>
+              <th>Name</th>
+              <th>Aussaat</th>
+              <th>Wachstum</th>
+              <th>Aktionen</th>
+            </tr>
+          </thead>
+          <tbody>
+            {{if .Crops}}
+              {{range .Crops}}
+              <tr>
+                <form method="post" action="/crops/update">
+                  <td>
+                    <input type="hidden" name="id" value="{{.ID}}">
+                    <input type="text" name="name" value="{{.Name}}" maxlength="80" required>
+                  </td>
+                  <td class="inline-inputs">
+                    <input type="number" name="sow_start_month" min="1" max="12" value="{{.SowStartMonth}}" required>
+                    <span>bis</span>
+                    <input type="number" name="sow_end_month" min="1" max="12" value="{{.SowEndMonth}}" required>
+                  </td>
+                  <td>
+                    <input type="number" name="grow_months" min="1" max="24" value="{{.GrowMonths}}" required>
+                  </td>
+                  <td class="actions">
+                    <button type="submit" class="btn-small">Speichern</button>
+                </form>
+                <form method="post" action="/crops/delete" onsubmit="return confirm('Feldfrucht wirklich loeschen?');">
+                  <input type="hidden" name="id" value="{{.ID}}">
+                  <button type="submit" class="btn-small danger">Loeschen</button>
+                </form>
+                  </td>
+              </tr>
+              {{end}}
+            {{else}}
+              <tr><td colspan="4">Keine Feldfruechte vorhanden.</td></tr>
+            {{end}}
+          </tbody>
+        </table>
+      </div>
+    </section>
+
+    <section class="card">
+      <h2>Anbau planen</h2>
+      <form method="post" action="/plans/create" class="grid">
+        <label>Planungsziel
+          <select name="target_ref" required>
+            <option value="">Bitte waehlen</option>
+            {{range .PlanningTargets}}
+            <option value="{{.Ref}}">{{.Label}}</option>
+            {{end}}
+          </select>
+        </label>
         <label>Feldfrucht
           <select name="crop_id" required>
             <option value="">Bitte waehlen</option>
             {{range .Crops}}
-            <option value="{{.ID}}">{{.Name}} (Aussaat Monat {{.SowStartMonth}}-{{.SowEndMonth}})</option>
+            <option value="{{.ID}}">{{.Name}} (Monat {{.SowStartMonth}}-{{.SowEndMonth}})</option>
             {{end}}
           </select>
         </label>
-
         <label>Startmonat
           <select name="start_month" required>
             {{range .Months}}
@@ -93,15 +248,12 @@
             {{end}}
           </select>
         </label>
-
         <label>Starttag
           <input type="number" name="start_day" min="1" max="{{.DaysPerMonth}}" value="{{.NowDay}}" required>
         </label>
-
         <label class="full">Notiz
           <input type="text" name="notes" maxlength="255">
         </label>
-
         <button type="submit">Plan speichern</button>
       </form>
     </section>
@@ -112,7 +264,7 @@
         <table>
           <thead>
             <tr>
-              <th>Feld</th>
+              <th>Ziel</th>
               <th>Frucht</th>
               <th>Aussaat</th>
               <th>Ernte</th>
@@ -123,7 +275,7 @@
             {{if .Plans}}
               {{range .Plans}}
               <tr>
-                <td>Feld {{.FieldNumber}}{{if .FieldName}} ({{.FieldName}}){{end}}</td>
+                <td>{{.TargetName}}</td>
                 <td>{{.CropName}}</td>
                 <td>Monat {{.StartMonth}} Tag {{.StartDay}}</td>
                 <td>Monat {{.HarvestMonth}} Tag {{.HarvestDay}}</td>