todo-server/server/ajax/storage.go

package ajax

import (
	"bytes"
	"encoding/gob"
	"local/todo-server/server/ajax/form"
	"local/todo-server/server/ajax/list"
	"local/todo-server/server/ajax/task"
	"net/http"
	"path"
	"sort"
	"strings"
)

func (a *Ajax) Cur(r *http.Request) (string, string, []string) {
	listID := form.Get(r, "list")
	taskID := form.Get(r, "id")
	if listID == "" {
		listID, _ = a.taskIDToListID(taskID)
	}
	tags, _ := r.URL.Query()["t"]
	return listID, taskID, tags
}

func (a *Ajax) taskIDToListID(taskID string) (string, error) {
	var listID string
	err := a.storageGet(path.Join("task", taskID, "map"), &listID)
	return listID, err
}

func (a *Ajax) storageListLists(filters ...func(t *list.List) bool) ([]*list.List, error) {
	results, err := a.DB.List(nil, path.Join("list"), path.Join("list", "}"))
	if err != nil {
		return nil, err
	}
	lists := []*list.List{}
	for _, result := range results {
		if d := path.Dir(result); d != "list" {
			continue
		}
		list, err := a.storageGetList(path.Base(result))
		if err != nil {
			return nil, err
		}
		filtered := true
		for _, f := range filters {
			if !f(list) {
				filtered = false
				break
			}
		}
		if filtered {
			lists = append(lists, list)
		}
	}
	return lists, nil
}

func (a *Ajax) storageListTasks(listID string, filters ...func(t *task.Task) bool) ([]*task.Task, error) {
	results, err := a.DB.List(nil, path.Join("list", listID, "task"), path.Join("list", listID, "task", "}"))
	if err != nil {
		return nil, err
	}
	tasks := []*task.Task{}
	for _, result := range results {
		taskID := path.Base(result)
		if taskID == "" {
			continue
		}
		task, err := a.storageGetTask(taskID)
		if err != nil {
			return nil, err
		}
		filtered := true
		for _, f := range filters {
			if !f(task) {
				filtered = false
				break
			}
		}
		if filtered {
			tasks = append(tasks, task)
		}
	}
	sort.SliceStable(tasks, func(i, j int) bool {
		if tasks[i].Index == tasks[j].Index {
			return tasks[i].Created.Before(tasks[j].Created)
		}
		return tasks[i].Index < tasks[j].Index
	})
	return tasks, nil
}

func (a *Ajax) storageGetTask(taskID string) (*task.Task, error) {
	var listID string
	if err := a.storageGet(path.Join("task", taskID, "map"), &listID); err != nil {
		return nil, err
	}
	var task task.Task
	err := a.storageGet(path.Join("list", listID, "task", taskID), &task)
	return &task, err
}

func (a *Ajax) storageSetTask(listID string, newTask *task.Task) error {
	if newTask == nil {
		newTask = &task.Task{
			UUID: "nil",
		}
	}
	if err := a.storageSet(path.Join("task", newTask.UUID, "map"), listID); err != nil {
		return err
	}
	return a.storageSet(path.Join("list", listID, "task", newTask.UUID), *newTask)
}

func (a *Ajax) storageDelTask(taskID string) error {
	var listID string
	if err := a.storageGet(path.Join("task", taskID, "map"), &listID); err != nil {
		return err
	}
	if err := a.storageDel(path.Join("task", taskID, "map")); err != nil {
		return err
	}
	return a.storageDel(path.Join("list", listID, "task", taskID))
}

func (a *Ajax) storageGetList(listID string) (*list.List, error) {
	listID = strings.TrimSuffix(listID, "/") + "/"
	var list list.List
	err := a.storageGet(path.Join("list", listID), &list)
	return &list, err
}

func (a *Ajax) storageSetList(list *list.List) error {
	return a.storageSet(path.Join("list", list.UUID), *list)
}

func (a *Ajax) storageDelList(listID string) error {
	listID = strings.TrimSuffix(listID, "/") + "/"
	return a.storageDel(path.Join("list", listID))
}

func (a *Ajax) storageSet(key string, value interface{}) error {
	buff := bytes.NewBuffer(nil)
	encoder := gob.NewEncoder(buff)
	if err := encoder.Encode(value); err != nil {
		return err
	}
	return a.DB.Set(key, buff.Bytes())
}

func (a *Ajax) storageGet(key string, value interface{}) error {
	b, err := a.DB.Get(key)
	if err != nil {
		return err
	}
	buff := bytes.NewBuffer(b)
	decoder := gob.NewDecoder(buff)
	return decoder.Decode(value)
}

func (a *Ajax) storageDel(key string) error {
	return a.DB.Set(key, nil)
}