Golang Todo 功能模块：任务全生命周期管理、用户管理和定时任务推送

以下是一个简单的 todo 功能模块示例，实现了基本的任务创建、更新、删除、查询和定时任务推送功能，用户管理部分待完善：

package main

import (
    "fmt"
    "log"
    "time"
)

type Todo struct {
    ID        int
    Title     string
    Completed bool
    Due       time.Time
    CreatedAt time.Time
    UpdatedAt time.Time
}

type TodoList struct {
    Todos []Todo
}

func NewTodoList() *TodoList {
    return &TodoList{}
}

func (l *TodoList) Add(todo Todo) {
    l.Todos = append(l.Todos, todo)
}

func (l *TodoList) Update(id int, todo Todo) {
    for i, t := range l.Todos {
        if t.ID == id {
            l.Todos[i] = todo
            return
        }
    }
}

func (l *TodoList) Delete(id int) {
    for i, t := range l.Todos {
        if t.ID == id {
            l.Todos = append(l.Todos[:i], l.Todos[i+1:]...)
            return
        }
    }
}

func (l *TodoList) GetById(id int) *Todo {
    for _, t := range l.Todos {
        if t.ID == id {
            return &t
        }
    }
    return nil
}

func (l *TodoList) GetByDue(due time.Time) []Todo {
    var todos []Todo
    for _, t := range l.Todos {
        if t.Due.Equal(due) {
            todos = append(todos, t)
        }
    }
    return todos
}

func (l *TodoList) PushDueTasks() {
    now := time.Now()
    due := now.Add(24 * time.Hour)
    todos := l.GetByDue(due)
    for _, t := range todos {
        fmt.Printf('Pushing task due at %s: %s\n', t.Due, t.Title)
        // TODO: send push notification to user
    }
}

func main() {
    todoList := NewTodoList()

    // create a new task
    task1 := Todo{
        ID:        1,
        Title:     'Buy groceries',
        Completed: false,
        Due:       time.Date(2021, time.September, 1, 0, 0, 0, 0, time.UTC),
        CreatedAt: time.Now(),
        UpdatedAt: time.Now(),
    }
    todoList.Add(task1)

    // update a task
    task2 := Todo{
        ID:        2,
        Title:     'Clean the house',
        Completed: false,
        Due:       time.Date(2021, time.September, 2, 0, 0, 0, 0, time.UTC),
        CreatedAt: time.Now(),
        UpdatedAt: time.Now(),
    }
    todoList.Update(1, task2)

    // delete a task
    todoList.Delete(1)

    // get a task by id
    task3 := todoList.GetById(2)
    if task3 != nil {
        fmt.Println(task3.Title)
    }

    // get tasks due on a specific date
    tasks4 := todoList.GetByDue(time.Date(2021, time.September, 2, 0, 0, 0, 0, time.UTC))
    for _, t := range tasks4 {
        fmt.Println(t.Title)
    }

    // push due tasks
    todoList.PushDueTasks()
}