// Copyright (C) 2020 Marius Schellenberger

package pve

import (
	"context"
	"errors"
	"fmt"
	"strings"
	"time"
)

const (
	TaskTimeout             = 300
	TaskStatusCheckInterval = 2
	TaskExitStatusOK        = "OK"
	TaskStatusRunning       = "running"
	TaskStatusStopped       = "stopped"
)

type Task struct {
	ID         string `json:"upid"`
	Type       string `json:"type"`
	Status     string `json:"status"`
	Exitstatus string `json:"exitstatus"`
}

type TaskClient struct {
	client *Client
}

func nodeFromTaskID(taskid string) (string, error) {
	a := strings.SplitN(taskid, ":", 3)
	if len(a) < 2 {
		return "", errors.New("error parsing taskid")
	}
	return a[1], nil
}

func (c *TaskClient) MustGet(ctx context.Context, taskid string) (t *Task) {
	t = &Task{ID: taskid}
	task, err := c.Get(ctx, taskid)
	if err == nil {
		t = task
	}
	return
}

func (c *TaskClient) Get(ctx context.Context, taskid string) (t *Task, err error) {
	node, err := nodeFromTaskID(taskid)
	if err != nil {
		return
	}
	req, err := c.client.NewRequest(ctx, "GET", fmt.Sprintf("/nodes/%s/tasks/%s/status", node, taskid), nil)
	if err != nil {
		return
	}
	t = &Task{ID: taskid}
	_, err = c.client.Do(req, t)
	return
}

type OnTaskChange func(t *Task)

func (c *TaskClient) Wait(ctx context.Context, t *Task, f OnTaskChange) error {
	if f != nil && t.Status != "" {
		f(t)
	}
	if t.Status == TaskStatusStopped {
		if t.Exitstatus == TaskExitStatusOK {
			return nil
		}
		return errors.New(t.Exitstatus)
	}
	waited := 0
	for waited < TaskTimeout {
		task, err := c.Get(ctx, t.ID)
		if err != nil {
			return err
		}
		if task.Status != t.Status {
			if f != nil {
				f(task)
			}
			if task.Status == TaskStatusStopped {
				if task.Exitstatus == TaskExitStatusOK {
					return nil
				}
				return errors.New(task.Exitstatus)
			}
		}
		time.Sleep(TaskStatusCheckInterval * time.Second)
		waited = waited + TaskStatusCheckInterval
	}
	return errors.New("task wait timeout for: " + t.ID)
}