Implement change order endpoint

server/ajax/task.go

@@ -6,7 +6,9 @@ import (
 	"fmt"
 	"local/todo-server/server/ajax/form"
 	"local/todo-server/server/ajax/task"
+	"log"
 	"net/http"
+	"strconv"
 	"strings"
 )
 
@@ -45,6 +47,10 @@ func (a *Ajax) loadTasks(w http.ResponseWriter, r *http.Request) error {
 	if err != nil {
 		return err
 	}
+	log.Println(listID)
+	for _, task := range tasks {
+		log.Println(task.Index, task.Title)
+	}
 	return json.NewEncoder(w).Encode(map[string]interface{}{"list": tasks})
 }
 
@@ -147,3 +153,56 @@ func (a *Ajax) moveTask(w http.ResponseWriter, r *http.Request) error {
 func (a *Ajax) parseTaskStr(w http.ResponseWriter, r *http.Request) error {
 	return errors.New("not impl")
 }
+
+func (a *Ajax) changeOrder(w http.ResponseWriter, r *http.Request) error {
+	order := form.Get(r, "order")
+	orders := strings.Split(order, "&")
+	sum := 0
+	zero := ""
+	for _, order := range orders {
+		taskIDDelta := strings.Split(order, "=")
+		if len(taskIDDelta) < 2 {
+			continue
+		}
+		taskID := taskIDDelta[0]
+		delta, _ := strconv.Atoi(taskIDDelta[1])
+		if delta < 0 {
+			delta = -1
+		} else {
+			delta = 0
+		}
+		task, err := a.storageGetTask(taskID)
+		if err != nil {
+			return err
+		}
+		listID, err := a.taskIDToListID(taskID)
+		if err != nil {
+			return err
+		}
+		task.Index += delta
+		if err := a.storageSetTask(listID, task); err != nil {
+			return err
+		}
+		if delta == 0 {
+			zero = taskID
+		}
+		sum += delta
+	}
+	if zero == "" || sum == 0 {
+		return nil
+	}
+	task, err := a.storageGetTask(zero)
+	if err != nil {
+		return err
+	}
+	listID, err := a.taskIDToListID(zero)
+	if err != nil {
+		return err
+	}
+	task.Index -= sum
+	if err := a.storageSetTask(listID, task); err != nil {
+		return err
+	}
+	fmt.Fprint(w, `{"total":1}`)
+	return nil
+}