package main

import (
	"encoding/json"
	"fmt"
	"log"

	"github.com/nats-io/nats.go"
	"github.com/pkg/errors"
	"github.com/rosti-cz/node-api/apps"
	"github.com/rosti-cz/node-api/docker"
	"github.com/rosti-cz/node-api/node"
)

// This handler only passes messages to another function for easier testing
func messageHandler(msg *nats.Msg) {
	go _messageHandler(msg)
}

func _messageHandler(m *nats.Msg) error {
	message := RequestMessage{}
	err := json.Unmarshal(m.Data, &message)
	if err != nil {
		log.Println(errors.Wrap(err, "invalid JSON data in the incoming message"))
		return err
	}
	fmt.Printf("Received a message: %v\n", message)

	eventHandlerMap := map[string](func(m *nats.Msg, message *RequestMessage) error){
		"list":         listEventHandler,
		"get":          getEventHandler,
		"create":       createEventHandler,
		"update":       updateEventHandler,
		"delete":       deleteEventHandler,
		"stop":         stopEventHandler,
		"start":        startEventHandler,
		"restart":      restartEventHandler,
		"update_keys":  updateKeysEventHandler,
		"set_password": setPasswordEventHandler,
		"processes":    processesEventHandler,
		"enable_tech":  enableTechEventHandler,
		"rebuild":      rebuildEventHandler,
		"add_label":    addLabelEventHandler,
		"remove_label": removeLabelEventHandler,
		"list_orphans": listOrphansEventHandler,
		"node":         getNoteEventHandler,
	}

	if eventHandler, ok := eventHandlerMap[message.Type]; ok {
		return eventHandler(m, &message)
	} else {
		log.Println("ERROR: event handler not defined for " + message.Type)
	}

	// Set password for the app user in the container

	// Application processes

	// Enable one of the supported technologies or services (python, node, redis, ...)
	// Rebuilds existing app, it keeps the data but creates the container again
	// Adds new label
	// Removes existing label

	// Orphans returns directories in /srv that doesn't match any hosted application
	// Return info about the node including performance index

	return nil
}

// Returns list of apps
func listEventHandler(m *nats.Msg, message *RequestMessage) error {
	log.Println("> List")

	err := gatherStates()
	if err != nil {
		return errorReplyFormater(m, "backend error", err)
	}

	applications, err := apps.List()

	if err != nil {
		return errorReplyFormater(m, "backend error", err)
	}

	reply := ReplyMessage{
		Payload: applications,
	}

	data, err := json.Marshal(reply)
	if err != nil {
		return errorReplyFormater(m, "reply formatter error", err)
	}

	err = m.Respond(data)
	if err != nil {
		log.Println("ERROR: list apps:", err.Error())
	}

	return err
}

// Returns one app
func getEventHandler(m *nats.Msg, message *RequestMessage) error {

	err := updateState(message.AppName)
	if err != nil {
		return errorReplyFormater(m, "backend error", err)
	}

	app, err := apps.Get(message.AppName)
	if err != nil {
		return errorReplyFormater(m, "backend error", err)
	}

	reply := ReplyMessage{
		AppName: app.Name,
		Payload: app,
	}

	data, err := json.Marshal(reply)
	if err != nil {
		return errorReplyFormater(m, "reply formatter error", err)
	}

	err = m.Respond(data)
	if err != nil {
		log.Println("ERROR: get app:", err.Error())
	}

	return err
}

// Create a new app
func createEventHandler(m *nats.Msg, message *RequestMessage) error {

	appTemplate := apps.App{}
	body := []byte(message.Payload)
	err := json.Unmarshal(body, &appTemplate)
	if err != nil {
		log.Println("ERROR create application problem: " + err.Error())
		publish(appTemplate.Name, "payload parsing problem", true)
		return err
	}

	err = apps.New(appTemplate.Name, appTemplate.SSHPort, appTemplate.HTTPPort, appTemplate.Image, appTemplate.CPU, appTemplate.Memory)
	if err != nil {
		if validationError, ok := err.(apps.ValidationError); ok {
			log.Println("ERROR create application problem: " + validationError.Error())
			publish(appTemplate.Name, "validation problem", true)
			return err
		}
		log.Println("ERROR create application problem: " + err.Error())
		publish(appTemplate.Name, "backend problem", true)
		return err
	}

	container := docker.Container{
		App: &appTemplate,
	}

	err = container.Create()
	if err != nil {
		log.Println("ERROR create application problem: " + err.Error())
		publish(appTemplate.Name, "backend problem", true)
		return err
	}

	err = container.Start()
	if err != nil {
		log.Println("ERROR create application problem: " + err.Error())
		publish(appTemplate.Name, "backend problem", true)
		return err
	}

	publish(appTemplate.Name, "created", false)

	return nil
}

// Update existing app
func updateEventHandler(m *nats.Msg, message *RequestMessage) error {

	appTemplate := apps.App{}
	body := []byte(message.Payload)
	err := json.Unmarshal(body, &appTemplate)
	if err != nil {
		log.Println("ERROR update application problem: " + err.Error())
		publish(appTemplate.Name, "payload parsing problem", true)
		return err
	}

	app, err := apps.Update(message.AppName, appTemplate.SSHPort, appTemplate.HTTPPort, appTemplate.Image, appTemplate.CPU, appTemplate.Memory)
	if err != nil {
		if validationError, ok := err.(apps.ValidationError); ok {
			log.Println("ERROR update application problem: " + validationError.Error())
			publish(appTemplate.Name, "backend problem", true)
			return err
		}
		log.Println("ERROR update application problem: " + err.Error())
		publish(appTemplate.Name, "backend problem", true)
		return err
	}

	container := docker.Container{
		App: app,
	}

	err = container.Destroy()
	if err != nil && err.Error() == "no container found" {
		// We don't care if the container didn't exist anyway
		err = nil
	}
	if err != nil {
		log.Println("ERROR update application problem: " + err.Error())
		publish(appTemplate.Name, "backend problem", true)
		return err
	}

	err = container.Create()
	if err != nil {
		log.Println("ERROR update application problem: " + err.Error())
		publish(appTemplate.Name, "backend problem", true)
		return err
	}

	err = container.Start()
	if err != nil {
		log.Println("ERROR update application problem: " + err.Error())
		publish(appTemplate.Name, "backend problem", true)
		return err
	}

	publish(appTemplate.Name, "updated", false)
	return nil
}

// Delete one app
func deleteEventHandler(m *nats.Msg, message *RequestMessage) error {
	app, err := apps.Get(message.AppName)
	if err != nil {
		log.Println("ERROR: delete app:", err.Error())
	}

	container := docker.Container{
		App: app,
	}

	status, err := container.Status()
	if err != nil {
		log.Println("ERROR delete application problem: " + err.Error())
		publish(app.Name, "backend problem", true)
		return err
	}

	if status != "no-container" {
		// We stop the container first
		err = container.Stop()
		if err != nil {
			log.Println("ERROR delete application problem: " + err.Error())
			publish(app.Name, "backend problem", true)
			return err
		}

		// Then delete it
		err = container.Delete()
		if err != nil {
			log.Println("ERROR delete application problem: " + err.Error())
			publish(app.Name, "backend problem", true)
			return err
		}
	}

	err = apps.Delete(app.Name)
	if err != nil {
		log.Println("ERROR delete application problem: " + err.Error())
		publish(app.Name, "backend problem", true)
		return err
	}

	publish(app.Name, "deleted", false)

	return nil
}

// Stop existing app
func stopEventHandler(m *nats.Msg, message *RequestMessage) error {
	app, err := apps.Get(message.AppName)
	if err != nil {
		log.Println("ERROR stop application problem: " + err.Error())
		publish(app.Name, "backend problem", true)
		return err
	}

	container := docker.Container{
		App: app,
	}

	status, err := container.Status()
	if err != nil {
		log.Println("ERROR stop application problem: " + err.Error())
		publish(app.Name, "backend problem", true)
		return err
	}

	// Stop the container only when it exists
	if status != "no-container" {
		err = container.Stop()
		if err != nil {
			log.Println("ERROR stop application problem: " + err.Error())
			publish(app.Name, "backend problem", true)
			return err
		}
	}

	publish(app.Name, "stopped", false)

	return nil
}

// Start existing app
func startEventHandler(m *nats.Msg, message *RequestMessage) error {
	app, err := apps.Get(message.AppName)
	if err != nil {
		log.Println("ERROR start application problem: " + err.Error())
		publish(app.Name, "backend problem", true)
		return err
	}

	container := docker.Container{
		App: app,
	}

	status, err := container.Status()
	if err != nil {
		return err
	}
	if status == "no-container" {
		err = container.Create()
		if err != nil {
			log.Println("ERROR start application problem: " + err.Error())
			publish(app.Name, "backend problem", true)
			return err
		}
	}

	err = container.Start()
	if err != nil {
		log.Println("ERROR start application problem: " + err.Error())
		publish(app.Name, "backend problem", true)
		return err
	}

	publish(app.Name, "started", false)

	return nil
}

// Restart existing app
func restartEventHandler(m *nats.Msg, message *RequestMessage) error {
	app, err := apps.Get(message.AppName)
	if err != nil {
		log.Println("ERROR restart application problem: " + err.Error())
		publish(app.Name, "backend problem", true)
		return err
	}

	container := docker.Container{
		App: app,
	}

	err = container.Restart()
	if err != nil {
		log.Println("ERROR restart application problem: " + err.Error())
		publish(app.Name, "backend problem", true)
		return err
	}

	publish(app.Name, "restarted", false)

	return nil
}

// Copies body of the request into /srv/.ssh/authorized_keys
func updateKeysEventHandler(m *nats.Msg, message *RequestMessage) error {
	err := waitForApp(message.AppName)
	if err != nil {
		log.Println("ERROR enable tech problem: " + err.Error())
		publish(message.AppName, "backend problem", true)
		return err
	}

	body := message.Payload

	app, err := apps.Get(message.AppName)
	if err != nil {
		log.Println("ERROR keys update problem: " + err.Error())
		publish(app.Name, "backend problem", true)
		return err
	}

	container := docker.Container{
		App: app,
	}

	err = container.SetFileContent(sshPubKeysLocation, body+"\n", "0600")
	if err != nil {
		log.Println("ERROR keys update problem: " + err.Error())
		publish(app.Name, "backend problem", true)
		return err
	}

	publish(app.Name, "keys updated", false)

	return nil
}

// Set password for the app user in the container
func setPasswordEventHandler(m *nats.Msg, message *RequestMessage) error {
	err := waitForApp(message.AppName)
	if err != nil {
		log.Println("ERROR enable tech problem: " + err.Error())
		publish(message.AppName, "backend problem", true)
		return err
	}

	password := message.Payload

	app, err := apps.Get(message.AppName)
	if err != nil {
		log.Println("ERROR password update problem: " + err.Error())
		publish(app.Name, "backend problem", true)
		return err
	}

	container := docker.Container{
		App: app,
	}

	err = container.SetPassword(password)
	if err != nil {
		log.Println("ERROR password update problem: " + err.Error())
		publish(app.Name, "backend problem", true)
		return err
	}

	publish(app.Name, "password updated", false)

	return nil
}

// Application processes
func processesEventHandler(m *nats.Msg, message *RequestMessage) error {
	app, err := apps.Get(message.AppName)
	if err != nil {
		log.Println("ERROR processes list problem: " + err.Error())
		publish(app.Name, "backend problem", true)
		return err
	}

	container := docker.Container{
		App: app,
	}

	processes, err := container.GetProcessList()
	if err != nil {
		log.Println("ERROR processes list problem: " + err.Error())
		publish(app.Name, "backend problem", true)
		return err
	}

	reply := ReplyMessage{
		Payload: processes,
	}

	data, err := json.Marshal(reply)
	if err != nil {
		log.Println("ERROR processes list problem: " + err.Error())
		publish(app.Name, "backend problem", true)
		return err
	}
	err = m.Respond(data)
	if err != nil {
		log.Println("ERROR processes list problem: " + err.Error())
		return err
	}

	return nil
}

// Enable one of the supported technologies or services (python, node, redis, ...)
func enableTechEventHandler(m *nats.Msg, message *RequestMessage) error {
	service := message.Payload

	err := waitForApp(message.AppName)
	if err != nil {
		log.Println("ERROR enable tech problem: " + err.Error())
		publish(message.AppName, "backend problem", true)
		return err
	}

	app, err := apps.Get(message.AppName)
	if err != nil {
		log.Println("ERROR enable tech problem: " + err.Error())
		publish(app.Name, "backend problem", true)
		return err
	}

	container := docker.Container{
		App: app,
	}

	err = container.SetTechnology(service)
	if err != nil {
		log.Println("ERROR enable tech problem: " + err.Error())
		publish(app.Name, "backend problem", true)
		return err
	}

	publish(app.Name, "tech updated", false)

	return nil
}

// Rebuilds existing app, it keeps the data but creates the container again
func rebuildEventHandler(m *nats.Msg, message *RequestMessage) error {
	app, err := apps.Get(message.AppName)
	if err != nil {
		log.Println("ERROR rebuild app problem: " + err.Error())
		publish(app.Name, "backend problem", true)
		return err
	}

	container := docker.Container{
		App: app,
	}

	err = container.Destroy()
	if err != nil && err.Error() == "no container found" {
		// We don't care if the container didn't exist anyway
		err = nil
	}
	if err != nil {
		log.Println("ERROR rebuild app problem: " + err.Error())
		publish(app.Name, "backend problem", true)
		return err
	}

	err = container.Create()
	if err != nil {
		log.Println("ERROR rebuild app problem: " + err.Error())
		publish(app.Name, "backend problem", true)
		return err
	}

	err = container.Start()
	if err != nil {
		log.Println("ERROR rebuild app problem: " + err.Error())
		publish(app.Name, "backend problem", true)
		return err
	}

	publish(app.Name, "app rebuild", false)

	return nil
}

// Adds new label
func addLabelEventHandler(m *nats.Msg, message *RequestMessage) error {
	label := message.Payload

	err := apps.AddLabel(message.AppName, label)
	if err != nil {
		log.Println("ERROR add label problem: " + err.Error())
		publish(message.AppName, "backend problem", true)
		return err
	}

	publish(message.AppName, "label added", false)

	return nil
}

// Removes existing label
func removeLabelEventHandler(m *nats.Msg, message *RequestMessage) error {
	label := message.Payload

	err := apps.RemoveLabel(message.AppName, label)
	if err != nil {
		log.Println("ERROR remove label problem: " + err.Error())
		publish(message.AppName, "backend problem", true)
		return err
	}

	publish(message.AppName, "label removed", false)

	return nil
}

// Orphans returns directories in /srv that doesn't match any hosted application
func listOrphansEventHandler(m *nats.Msg, message *RequestMessage) error {
	reply := ReplyMessage{
		Error:   true,
		Payload: "not implemented yet",
	}

	data, err := json.Marshal(reply)
	if err != nil {
		log.Println("ERROR orphans list problem: " + err.Error())
		return err
	}

	err = m.Respond(data)
	if err != nil {
		log.Println("ERROR orphans list problem: " + err.Error())
		return err
	}

	return nil
}

// Return info about the node including performance index
func getNoteEventHandler(m *nats.Msg, message *RequestMessage) error {
	node, err := node.GetNodeInfo()
	if err != nil {
		log.Println("ERROR performance index problem: " + err.Error())
		publish(message.AppName, "backend problem", true)
		return err
	}

	reply := ReplyMessage{
		Payload: node,
	}

	data, err := json.Marshal(reply)
	if err != nil {
		log.Println("ERROR performance index problem: " + err.Error())
		publish(message.AppName, "backend problem", true)
		return err
	}

	err = m.Respond(data)
	if err != nil {
		log.Println("ERROR performance index problem: " + err.Error())
		return err
	}

	return nil
}