<template>
  <div id="root">
    <div class="todo-container">
      <div class="todo-wrap">
        <MyHeader @addTodo="addTodo"></MyHeader>
        <MyList :todos="todos"></MyList>
        <MyFooter :todos="todos" @checkAllTodo="checkAllTodo" @cleatAllTodo="cleatAllTodo"></MyFooter>
      </div>
    </div>
  </div>
</template>

<script>
import pubsub from 'pubsub-js'
import MyHeader from "./components/MyHeader.vue";
import MyList from "./components/MyList.vue";
import MyFooter from "./components/MyFooter.vue";

export default {
    name: "App",
    components: { MyHeader, MyList, MyFooter },
    data() {
        return {
            todos: JSON.parse(localStorage.getItem('todos')) || []
        };
    },
    methods:{
        //添加一个todo
        addTodo(todoObj){
            // console.log('我是App组件，我收到了数据：',todoObj)
            this.todos.unshift(todoObj)
        },

        //勾选或取消勾选一个todo
        checkTodo(id){
            this.todos.forEach((todo) => {
                if(todo.id === id) todo.done = !todo.done
            })
        },

        //更新一个todo
        updateTodo(id,title){
            this.todos.forEach((todo) => {
                if(todo.id === id) todo.title = title
            })
        },

        //删除一个todo
        deleteTodo(_,id){   
            //使用了消息订阅与发布，当deleteTodo作为消息的回调使用时，会接收到两个参数，
            //第一个参数是msgName，由于本例用不上，所以使用下划线_，表示占位
            // const todos = this.todos.filter((todo) => {
            //     return todo.id !== id
            // })
            //简化写法
            this.todos = this.todos.filter(todo => todo.id !== id)
        },

        //全选或取消全选
        checkAllTodo(done){
            this.todos.forEach((todo) => {
                todo.done = done
            })
        },

        //清除已经完成的todo
        cleatAllTodo(){
            this.todos = this.todos.filter((todo) => {
                return !todo.done
            })
        }
    },

    // 实现本地存储
    watch:{
        todos:{
            deep:true,
            handler(value){
                localStorage.setItem('todos',JSON.stringify(value))
            }
        }
    },
    mounted(){
        this.$bus.$on('checkTodo',this.checkTodo)
        // this.$bus.$on('deleteTodo',this.deleteTodo)
        this.pubId = pubsub.subscribe('deleteTodo',this.deleteTodo)
        this.$bus.$on('updateTodo',this.updateTodo)
    },

    beforeDestroy(){
        this.$bus.$off('checkTodo')
        // this.$bus.$off('deleteTodo')
        pubsub.unsubscribe(this.pubId)
        this.$bus.$off('updateTodo')
    }
};
</script>


<style>
/*base*/
body {
  background: #fff;
}

.btn {
  display: inline-block;
  padding: 4px 12px;
  margin-bottom: 0;
  font-size: 14px;
  line-height: 20px;
  text-align: center;
  vertical-align: middle;
  cursor: pointer;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.2),
    0 1px 2px rgba(0, 0, 0, 0.05);
  border-radius: 4px;
}

.btn-danger {
  color: #fff;
  background-color: #da4f49;
  border: 1px solid #bd362f;
}

.btn-edit {
  color: #fff;
  background-color: skyblue;
  border: 1px solid rgb(108, 201, 238);
  margin-right: 5px;
}

.btn-danger:hover {
  color: #fff;
  background-color: #bd362f;
}

.btn:focus {
  outline: none;
}

.todo-container {
  width: 600px;
  margin: 0 auto;
}
.todo-container .todo-wrap {
  padding: 10px;
  border: 1px solid #ddd;
  border-radius: 5px;
}
</style>