package main

import (
    "log"
    "time"

    "github.com/hibiken/asynq"
    "your/app/package/tasks"
)

const redisAddr = "127.0.0.1:6379"

func main() {
    client := asynq.NewClient(asynq.RedisClientOpt{Addr: redisAddr})
    defer client.Close()

    // ------------------------------------------------------
    // Example 1: Enqueue task to be processed immediately.
    //            Use (*Client).Enqueue method.
    // ------------------------------------------------------

    task, err := tasks.NewEmailDeliveryTask(42, "some:template:id")
    if err != nil {
        log.Fatalf("could not create task: %v", err)
    }
    info, err := client.Enqueue(task)
    if err != nil {
        log.Fatalf("could not enqueue task: %v", err)
    }
    log.Printf("enqueued task: id=%s queue=%s", info.ID, info.Queue)


    // ------------------------------------------------------------
    // Example 2: Schedule task to be processed in the future.
    //            Use ProcessIn or ProcessAt option.
    // ------------------------------------------------------------

    info, err = client.Enqueue(task, asynq.ProcessIn(24*time.Hour))
    if err != nil {
        log.Fatalf("could not schedule task: %v", err)
    }
    log.Printf("enqueued task: id=%s queue=%s", info.ID, info.Queue)


    // ----------------------------------------------------------------------------
    // Example 3: Set other options to tune task processing behavior.
    //            Options include MaxRetry, Queue, Timeout, Deadline, Unique etc.
    // ----------------------------------------------------------------------------

    task, err = tasks.NewImageResizeTask("https://example.com/myassets/image.jpg")
    if err != nil {
        log.Fatalf("could not create task: %v", err)
    }
    info, err = client.Enqueue(task, asynq.MaxRetry(10), asynq.Timeout(3 * time.Minute))
    if err != nil {
        log.Fatalf("could not enqueue task: %v", err)
    }
    log.Printf("enqueued task: id=%s queue=%s", info.ID, info.Queue)
}

// EnqueueContext enqueues the given task to a queue.
// EnqueueContent向队列中投递任务
//
// EnqueueContext returns TaskInfo and nil error if the task is enqueued successfully, otherwise returns a non-nil error.
// 如果任务成功投递，返回TaskInfo和nil，否则返回非nil的error
//
// The argument opts specifies the behavior of task processing.
// 参数opts指定了任务处理的行为
// If there are conflicting Option values the last one overrides others.
// 如果有冲突的Option值，最后一个会覆盖前面的
// Any options provided to NewTask can be overridden by options passed to Enqueue.
// 任何传递给NewTask的选项都可以被传递给Enqueue的选项覆盖
// By default, max retry is set to 25 and timeout is set to 30 minutes.
// 默认情况下，最大重试次数为25，超时时间为30分钟
//
// If no ProcessAt or ProcessIn options are provided, the task will be pending immediately.
// 如果没有提供ProcessAt或ProcessIn选项，任务将立即处于pending状态
//
// The first argument context applies to the enqueue operation. To specify task timeout and deadline, use Timeout and Deadline option instead.
// 第一个参数context应用于enqueue操作。要指定任务的超时时间和截止时间，请使用Timeout和Deadline选项
func (c *Client) EnqueueContext(ctx context.Context, task *Task, opts ...Option) (*TaskInfo, error) {
	if task == nil {
		return nil, fmt.Errorf("task cannot be nil")
	}
	if strings.TrimSpace(task.Type()) == "" {
		return nil, fmt.Errorf("task typename cannot be empty")
	}
	// merge task options with the options provided at enqueue time.
    // 将任务选项与enqueue时提供的选项合并
	opts = append(task.opts, opts...)
	opt, err := composeOptions(opts...)
	if err != nil {
		return nil, err
	}
	deadline := noDeadline
	if !opt.deadline.IsZero() {
		deadline = opt.deadline
	}
	timeout := noTimeout
	if opt.timeout != 0 {
		timeout = opt.timeout
	}
	if deadline.Equal(noDeadline) && timeout == noTimeout {
		// If neither deadline nor timeout are set, use default timeout.
		timeout = defaultTimeout
	}
	var uniqueKey string
	if opt.uniqueTTL > 0 {
		uniqueKey = base.UniqueKey(opt.queue, task.Type(), task.Payload())
	}
	msg := &base.TaskMessage{
		ID:        opt.taskID,
		Type:      task.Type(),
		Payload:   task.Payload(),
		Queue:     opt.queue,
		Retry:     opt.retry,
		Deadline:  deadline.Unix(),
		Timeout:   int64(timeout.Seconds()),
		UniqueKey: uniqueKey,
		GroupKey:  opt.group,
		Retention: int64(opt.retention.Seconds()),
	}
	now := time.Now()
	var state base.TaskState
	if opt.processAt.After(now) {
		err = c.schedule(ctx, msg, opt.processAt, opt.uniqueTTL)
		state = base.TaskStateScheduled
	} else if opt.group != "" {
		// Use zero value for processAt since we don't know when the task will be aggregated and processed.
        // 对于processAt使用零值，因为我们不知道任务何时被聚合和处理
		opt.processAt = time.Time{}
		err = c.addToGroup(ctx, msg, opt.group, opt.uniqueTTL)
		state = base.TaskStateAggregating
	} else {// 普通任务
		opt.processAt = now
		err = c.enqueue(ctx, msg, opt.uniqueTTL)
		state = base.TaskStatePending
	}
	switch {
	case errors.Is(err, errors.ErrDuplicateTask):
		return nil, fmt.Errorf("%w", ErrDuplicateTask)
	case errors.Is(err, errors.ErrTaskIdConflict):
		return nil, fmt.Errorf("%w", ErrTaskIDConflict)
	case err != nil:
		return nil, err
	}
	return newTaskInfo(msg, state, opt.processAt, nil), nil
}