/*
   Copyright (c) 2016 VMware, Inc. All Rights Reserved.
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/

package job

import (
	"time"

	"github.com/vmware/harbor/src/common/dao"
	"github.com/vmware/harbor/src/common/models"
	"github.com/vmware/harbor/src/common/utils/log"
)

// StateHandler handles transition, it associates with each state, will be called when
// SM enters and exits a state during a transition.
type StateHandler interface {
	// Enter returns the next state, if it returns empty string the SM will hold the current state or
	// or decide the next state.
	Enter() (string, error)
	//Exit should be idempotent
	Exit() error
}

// StatusUpdater implements the StateHandler interface which updates the status of a job in DB when the job enters
// a status.
type StatusUpdater struct {
	JobID int64
	State string
}

// Enter updates the status of a job and returns "_continue" status to tell state machine to move on.
// If the status is a final status it returns empty string and the state machine will be stopped.
func (su StatusUpdater) Enter() (string, error) {
	err := dao.UpdateRepJobStatus(su.JobID, su.State)
	if err != nil {
		log.Warningf("Failed to update state of job: %d, state: %s, error: %v", su.JobID, su.State, err)
	}
	var next = models.JobContinue
	if su.State == models.JobStopped || su.State == models.JobError || su.State == models.JobFinished {
		next = ""
	}
	return next, err
}

// Exit ...
func (su StatusUpdater) Exit() error {
	return nil
}

// Retry handles a special "retrying" in which case it will update the status in DB and reschedule the job
// via scheduler
type Retry struct {
	JobID int64
}

// Enter ...
func (jr Retry) Enter() (string, error) {
	err := dao.UpdateRepJobStatus(jr.JobID, models.JobRetrying)
	if err != nil {
		log.Errorf("Failed to update state of job :%d to Retrying, error: %v", jr.JobID, err)
	}
	go Reschedule(jr.JobID)
	return "", err
}

// Exit ...
func (jr Retry) Exit() error {
	return nil
}

// ImgPuller was for testing
type ImgPuller struct {
	img    string
	logger *log.Logger
}

// Enter ...
func (ip ImgPuller) Enter() (string, error) {
	ip.logger.Infof("I'm pretending to pull img:%s, then sleep 30s", ip.img)
	time.Sleep(30 * time.Second)
	ip.logger.Infof("wake up from sleep.... testing retry")
	return models.JobRetrying, nil
}

// Exit ...
func (ip ImgPuller) Exit() error {
	return nil
}

// ImgPusher is a statehandler for testing
type ImgPusher struct {
	targetURL string
	logger    *log.Logger
}

// Enter ...
func (ip ImgPusher) Enter() (string, error) {
	ip.logger.Infof("I'm pretending to push img to:%s, then sleep 30s", ip.targetURL)
	time.Sleep(30 * time.Second)
	ip.logger.Infof("wake up from sleep.... testing retry")
	return models.JobRetrying, nil
}

// Exit ...
func (ip ImgPusher) Exit() error {
	return nil
}
