package main

import (
	"container/list"
	"sync"
	"time"

	"github.com/474420502/focus/compare"
	pqueuekey "github.com/474420502/focus/priority_queuekey"
)

type Task struct {
	Name     string      `json:"name"`      // 任务名字
	Type     int64       `json:"type"`      // 类型
	Priority int64       `json:"priority"`  // 优先级 默认0
	CreateAt time.Time   `json:"create_at"` // 创建任务时间
	Info     interface{} `json:"info"`      // 任务的信息内容
}

type Queue struct {
	lock  sync.Mutex
	count uint64

	waitChans *list.List

	queue *pqueuekey.PriorityQueue
}

func NewQueue() *Queue {
	return &Queue{
		waitChans: list.New(),
		queue:     pqueuekey.New(compare.UInt64),
	}
}

func (q *Queue) Push(task *Task) {
	q.lock.Lock()
	defer q.lock.Unlock()

	if q.waitChans.Len() != 0 {
		element := q.waitChans.Front()
		ctask := element.Value.(chan *Task)
		ctask <- task
		q.waitChans.Remove(element)
		return
	}

	q.count++
	q.queue.Push(q.count, task)
}

func (q *Queue) Pop() (task *Task) {
	q.lock.Lock()
	defer q.lock.Unlock()
	q.count++

	if itask, ok := q.queue.Pop(); ok {
		return itask.(*Task)
	}

	return nil
}

func (q *Queue) popBlock(task chan *Task) {
	q.lock.Lock()
	defer q.lock.Unlock()

	if q.queue.Size() != 0 {
		itask, _ := q.queue.Pop()
		go func() { task <- itask.(*Task) }()
		return
	}

	q.waitChans.PushBack(task)
}

func (q *Queue) PopBlock() *Task {
	task := make(chan *Task)
	q.popBlock(task)
	return (<-task)
}