package glue

import (
	"errors"
	"fmt"
	"log"
	"strings"
	"time"

	"github.com/jinzhu/gorm"
	"github.com/rosti-cz/node-api/apps"
	"github.com/rosti-cz/node-api/containers"
	docker "github.com/rosti-cz/node-api/containers"
	"github.com/rosti-cz/node-api/detector"
	"github.com/rosti-cz/node-api/node"
)

// Wait for the container a little bit longer
const ENABLE_TECH_WAIT = 10

// Processor separates logic of apps, containers, detector and node from handlers.
// It defines common interface for both types of handlers, HTTP and the events.
type Processor struct {
	AppName           string
	DB                *gorm.DB
	SnapshotProcessor *apps.SnapshotProcessor
	NodeProcessor     *node.Processor
	WaitForAppLoops   uint // each loop is five seconds
	DockerSock        string
	BindIPHTTP        string
	BindIPSSH         string
	AppsPath          string
}

// Return prepared Container instance
func (p *Processor) getContainer() (containers.Container, error) {
	container := containers.Container{}

	processor := p.getAppProcessor()
	app, err := processor.Get(p.AppName)
	if err != nil {
		return container, err
	}

	container = docker.Container{
		App:        &app,
		DockerSock: p.DockerSock,
		BindIPHTTP: p.BindIPHTTP,
		BindIPSSH:  p.BindIPSSH,
		AppsPath:   p.AppsPath,
	}

	return container, nil
}

// returns instance of getAppProcessor
func (p *Processor) getAppProcessor() apps.AppsProcessor {
	processor := apps.AppsProcessor{
		DB: p.DB,
	}
	processor.Init()
	return processor
}

// waits until app is ready
func (p *Processor) waitForApp() error {
	sleepFor := 5 * time.Second
	loops := 6
	if p.WaitForAppLoops != 0 {
		loops = int(p.WaitForAppLoops)
	}

	statsProcessor := StatsProcessor{
		DB:         p.DB,
		DockerSock: p.DockerSock,
		BindIPHTTP: p.BindIPHTTP,
		BindIPSSH:  p.BindIPSSH,
		AppsPath:   p.AppsPath,
	}

	for i := 0; i < loops; i++ {
		err := statsProcessor.UpdateState(p.AppName)
		if err != nil {
			time.Sleep(sleepFor)
			continue
		}

		container, err := p.getContainer()
		if err != nil {
			return err
		}

		status, err := container.Status()
		if err != nil {
			return err
		}
		if status.Status == "running" {
			return nil
		}

		time.Sleep(sleepFor)
	}

	return errors.New("timeout reached")
}

// List returns list of apps
// noUpdate skips stats gathering to speed things up
func (p *Processor) List(noUpdate bool) (apps.Apps, error) {
	appList := apps.Apps{}

	if !noUpdate {
		statsProcessor := StatsProcessor{
			DB:         p.DB,
			DockerSock: p.DockerSock,
			BindIPHTTP: p.BindIPHTTP,
			BindIPSSH:  p.BindIPSSH,
			AppsPath:   p.AppsPath,
		}

		err := statsProcessor.GatherStates()
		if err != nil {
			return appList, fmt.Errorf("backend error: %v", err)
		}
	}

	processor := p.getAppProcessor()
	appList, err := processor.List()

	if err != nil {
		return appList, fmt.Errorf("backend error: %v", err)
	}

	return appList, err
}

// Get returns one app
func (p *Processor) Get(noUpdate bool) (apps.App, error) {
	app := apps.App{}

	if !noUpdate {
		statsProcessor := StatsProcessor{
			DB:         p.DB,
			DockerSock: p.DockerSock,
			BindIPHTTP: p.BindIPHTTP,
			BindIPSSH:  p.BindIPSSH,
			AppsPath:   p.AppsPath,
		}

		err := statsProcessor.UpdateState(p.AppName)
		if err != nil {
			return app, err
		}
	}

	processor := p.getAppProcessor()
	app, err := processor.Get(p.AppName)
	if err != nil {
		return app, err
	}

	// Gather runtime info about the container
	if !noUpdate {
		container := docker.Container{
			App:        &app,
			DockerSock: p.DockerSock,
			BindIPHTTP: p.BindIPHTTP,
			BindIPSSH:  p.BindIPSSH,
			AppsPath:   p.AppsPath,
		}

		status, err := container.Status()
		if err != nil {
			return app, err
		}
		if status.Status == "running" {
			var err error
			app.Techs, err = container.GetTechs()
			if err != nil {
				return app, err
			}
			app.PrimaryTech, err = container.GetPrimaryTech()
			if err != nil {
				return app, err
			}

			processList, err := container.GetSystemProcesses()
			if err != nil {
				return app, err
			}

			flags, err := detector.Check(processList)
			if err != nil {
				return app, err
			}
			app.Flags = flags.String()
		}
	}

	return app, nil
}

// Create creates a single app in the system
func (p *Processor) Create(appTemplate apps.App) error {
	err := p.Register(appTemplate)
	if err != nil {
		return err
	}

	container := docker.Container{
		App:        &appTemplate,
		DockerSock: p.DockerSock,
		BindIPHTTP: p.BindIPHTTP,
		BindIPSSH:  p.BindIPSSH,
		AppsPath:   p.AppsPath,
	}

	err = container.Create()
	if err != nil {
		return err
	}

	// Restore from snapshot if it's noted in the request
	if len(appTemplate.Snapshot) > 0 {
		log.Printf("App %s is going to be created from %s snapshot\n", appTemplate.Name, appTemplate.Snapshot)

		// Restore the data
		err = p.SnapshotProcessor.RestoreSnapshot(appTemplate.Snapshot, appTemplate.Name)
		if err != nil {
			return fmt.Errorf("failed to restore snapshot: %v", err)
		}
	}

	err = container.Start()
	if err != nil {
		return fmt.Errorf("failed to start container: %v", err)
	}

	// Wait for the app to be created
	err = p.waitForApp()
	if err != nil {
		return fmt.Errorf("failed to wait for app: %v", err)
	}
	time.Sleep(5 * time.Second) // We wait for a little bit longer to make sure the container is fully started

	// Setup SSH keys if it's noted in the request
	if len(appTemplate.Setup.SSHKeys) > 0 && len(appTemplate.Snapshot) == 0 {
		err = p.UpdateKeys(appTemplate.Setup.SSHKeys)
		if err != nil {
			return fmt.Errorf("failed to update keys: %v", err)
		}
	}

	// Setup technology if it's noted in the request
	if len(appTemplate.Setup.Tech) > 0 && len(appTemplate.Snapshot) == 0 {
		err = p.EnableTech(appTemplate.Setup.Tech, appTemplate.Setup.TechVersion)
		if err != nil {
			return fmt.Errorf("failed to enable tech: %v", err)
		}
	}

	// Set password if it's noted in the request
	if len(appTemplate.Setup.Password) > 0 && len(appTemplate.Snapshot) == 0 {
		err = p.SetPassword(appTemplate.Setup.Password)
		if err != nil {
			return fmt.Errorf("failed to set password: %v", err)
		}
	}

	// Changes port of the app hosted inside the container
	if appTemplate.AppPort != 0 && len(appTemplate.Snapshot) == 0 {
		err = container.SetAppPort(appTemplate.AppPort)
		if err != nil {
			return fmt.Errorf("failed to change app port to %d: %v", appTemplate.AppPort, err)
		}

		err = container.RestartProcess("nginx")
		if err != nil {
			return fmt.Errorf("failed to restart nginx: %v", err)
		}
	}

	return nil
}

// Register registers app without creating a container for it
// Returns app name and an error
func (p *Processor) Register(appTemplate apps.App) error {
	processor := p.getAppProcessor()
	err := processor.New(appTemplate.Name, appTemplate.SSHPort, appTemplate.HTTPPort, appTemplate.Image, appTemplate.CPU, appTemplate.Memory)
	if err != nil {
		if validationError, ok := err.(apps.ValidationError); ok {
			return fmt.Errorf("validation error: %v", validationError.Error())
		}
		return err
	}

	return nil
}

// Update updates application
func (p *Processor) Update(appTemplate apps.App) error {
	processor := p.getAppProcessor()
	app, err := processor.Update(appTemplate.Name, appTemplate.SSHPort, appTemplate.HTTPPort, appTemplate.Image, appTemplate.CPU, appTemplate.Memory)
	if err != nil {
		if validationError, ok := err.(apps.ValidationError); ok {
			return fmt.Errorf("validation error: %v", validationError.Error())
		}
		return err
	}

	container := docker.Container{
		App:        app,
		DockerSock: p.DockerSock,
		BindIPHTTP: p.BindIPHTTP,
		BindIPSSH:  p.BindIPSSH,
		AppsPath:   p.AppsPath,
	}

	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 {
		return err
	}

	err = container.Create()
	if err != nil {
		return err
	}

	err = container.Start()
	if err != nil {
		return err
	}

	return nil
}

// Delete removes app from the system
func (p *Processor) Delete() error {
	processor := p.getAppProcessor()
	container, err := p.getContainer()
	if err != nil {
		log.Println("ERROR: delete app:", err.Error())
	}

	status, err := container.Status()
	if err != nil {
		return err
	}

	if status.Status != "no-container" {
		// We stop the container first
		err = container.Stop()
		if err != nil {
			return err
		}

		// Then delete it
		err = container.Delete()
		if err != nil {
			return err
		}
	}

	err = processor.Delete(p.AppName)
	if err != nil {
		return err
	}

	return nil
}

// Stop stops app
func (p *Processor) Stop() error {
	container, err := p.getContainer()
	if err != nil {
		return err
	}

	status, err := container.Status()
	if err != nil {
		return err
	}

	// Stop the container only when it exists
	if status.Status != "no-container" {
		err = container.Stop()
		if err != nil {
			return err
		}

		err = container.Destroy()
		if err != nil {
			return err
		}
	}

	return nil
}

// Start starts app
func (p *Processor) Start() error {
	container, err := p.getContainer()
	if err != nil {
		return err
	}

	status, err := container.Status()
	if err != nil {
		return err
	}
	if status.Status == "no-container" {
		err = container.Create()
		if err != nil {
			return err
		}
	}

	err = container.Start()
	if err != nil {
		return err
	}

	return nil
}

// Restart restarts app
func (p *Processor) Restart() error {
	container, err := p.getContainer()
	if err != nil {
		return err
	}

	err = container.Restart()
	if err != nil {
		return err
	}

	return nil
}

// UpdateKeys uploads SSH keys into the container
// keys parameters is just a string, one key per line
func (p *Processor) UpdateKeys(keys string) error {
	err := p.waitForApp()
	if err != nil {
		return err
	}

	container, err := p.getContainer()
	if err != nil {
		return err
	}

	err = container.AppendFile(sshPubKeysLocation, keys+"\n", "0600")
	if err != nil {
		return err
	}

	return nil
}

// SetPassword sets up a new password to access the SSH user
func (p *Processor) SetPassword(password string) error {
	err := p.waitForApp()
	if err != nil {
		return err
	}

	container, err := p.getContainer()
	if err != nil {
		return err
	}

	err = container.SetPassword(password)
	if err != nil {
		return err
	}

	return nil
}

// Generate SSH key and adds it into authorized_keys
// These pair of keys is used for deployment.
// Returns private key, pubkey and error.
// Keys are returned every time even if it was already generated
func (p *Processor) GenerateDeploySSHKeys() (string, string, error) {
	container, err := p.getContainer()
	if err != nil {
		return "", "", err
	}

	// If the container is not running we skip this code
	status, err := container.Status()
	if err != nil {
		return "", "", err
	}
	if status.Status != "running" {
		return "", "", nil
	}

	created, err := container.GenerateDeploySSHKeys()
	if err != nil {
		return "", "", err
	}

	privateKey, pubKey, err := container.GetDeploySSHKeys()
	if err != nil {
		return "", "", err
	}

	if created {
		err = container.AppendFile(sshPubKeysLocation, pubKey+"\n", "0600")
		if err != nil {
			return "", "", err
		}
	}

	return privateKey, pubKey, nil
}

// Return SSH host key without hostname (first part of the line)
func (p *Processor) GetHostKey() (string, error) {
	container, err := p.getContainer()
	if err != nil {
		return "", err
	}

	// If the container is not running we skip this code
	status, err := container.Status()
	if err != nil {
		return "", err
	}
	if status.Status != "running" {
		return "", nil
	}

	hostKey, err := container.GetHostKey()
	if err != nil {
		return "", err
	}

	return hostKey, nil
}

// Processes returns list of supervisord processes
func (p *Processor) Processes() ([]docker.Process, error) {
	container, err := p.getContainer()
	if err != nil {
		return nil, err
	}

	processes, err := container.GetProcessList()
	if err != nil {
		return nil, err
	}

	return processes, nil
}

// EnableTech sets up runtime for new tech or new version a tech
func (p *Processor) EnableTech(service, version string) error {
	err := p.waitForApp()
	if err != nil {
		return err
	}

	time.Sleep(ENABLE_TECH_WAIT * time.Second)

	container, err := p.getContainer()
	if err != nil {
		return err
	}

	err = container.SetTechnology(service, version)
	if err != nil {
		return err
	}

	return nil
}

// Rebuild recreates container for app
func (p *Processor) Rebuild() error {
	container, err := p.getContainer()
	if err != nil {
		return err
	}

	err = container.Destroy()
	if err != nil && !strings.Contains(err.Error(), "no container found") {
		return err
	}

	err = container.Create()
	if err != nil {
		return err
	}

	err = container.Start()
	if err != nil {
		return err
	}

	return nil
}

// AddLabel adds a label to the app
func (p *Processor) AddLabel(label string) error {
	appProcessor := p.getAppProcessor()
	err := appProcessor.AddLabel(p.AppName, label)
	if err != nil {
		return err
	}

	return nil
}

// RemoveLabel removes a label from the app
func (p *Processor) RemoveLabel(label string) error {
	appProcessor := p.getAppProcessor()
	err := appProcessor.RemoveLabel(p.AppName, label)
	if err != nil {
		return err
	}

	return nil
}

// GetNote returns node's info
func (p *Processor) GetNode() (*node.Node, error) {
	node, err := p.NodeProcessor.GetNodeInfo()
	if err != nil {
		return nil, err
	}

	return node, nil
}

// CreateSnapshot creates a snapshot of given app
func (p *Processor) CreateSnapshot(labels []string) error {
	_, err := p.SnapshotProcessor.CreateSnapshot(p.AppName, labels)
	return err
}

// RestoreFromSnapshot restores app from given snapshot
func (p *Processor) RestoreFromSnapshot(snapshotName string) error {
	container, err := p.getContainer()

	// Stop the container
	status, err := container.Status()
	if err != nil {
		return err
	}

	// Stop the container only when it exists
	if status.Status != "no-container" {
		err = container.Stop()
		if err != nil {
			return err
		}
	}

	// Restore the data
	err = p.SnapshotProcessor.RestoreSnapshot(snapshotName, p.AppName)
	if err != nil {
		return err
	}

	// Start the container
	status, err = container.Status()
	if err != nil {
		return err
	}
	if status.Status == "no-container" {
		err = container.Create()
		if err != nil {
			return err
		}
	}

	err = container.Start()
	if err != nil {
		return err
	}

	return nil
}

// ListSnapshots returns list of snapshots
func (p *Processor) ListSnapshots() (SnapshotsMetadata, error) {
	snapshots, err := p.SnapshotProcessor.ListAppSnapshots(p.AppName)
	if err != nil {
		return SnapshotsMetadata{}, err
	}

	var output SnapshotsMetadata
	for _, snapshot := range snapshots {
		output = append(output, SnapshotMetadata{
			Key:      snapshot.KeyName(p.SnapshotProcessor.IndexLabel),
			Metadata: snapshot,
		})
	}

	return output, nil
}

// ListAppsSnapshots returns list of snapshots for given app list
func (p *Processor) ListAppsSnapshots(appNames []string) (SnapshotsMetadata, error) {
	snapshots, err := p.SnapshotProcessor.ListAppsSnapshots(appNames)
	if err != nil {
		return SnapshotsMetadata{}, err
	}

	var output SnapshotsMetadata
	for _, snapshot := range snapshots {
		output = append(output, SnapshotMetadata{
			Key:      snapshot.KeyName(p.SnapshotProcessor.IndexLabel),
			Metadata: snapshot,
		})
	}

	return output, nil
}

// ListSnapshotsByLabel returns list of snapshots by given label
func (p *Processor) ListSnapshotsByLabel(label string) (SnapshotsMetadata, error) {
	snapshots, err := p.SnapshotProcessor.ListAppsSnapshotsByLabel(label)
	if err != nil {
		return SnapshotsMetadata{}, err
	}

	var output SnapshotsMetadata
	for _, snapshot := range snapshots {
		output = append(output, SnapshotMetadata{
			Key:      snapshot.KeyName(p.SnapshotProcessor.IndexLabel),
			Metadata: snapshot,
		})
	}

	return output, nil
}

// GetSnapshot returns info about a single snapshot
func (p *Processor) GetSnapshot(snapshotName string) (SnapshotMetadata, error) {
	snapshot, err := p.SnapshotProcessor.GetSnapshot(snapshotName)
	if err != nil {
		return SnapshotMetadata{}, err
	}
	output := SnapshotMetadata{
		Key:      snapshot.KeyName(p.SnapshotProcessor.IndexLabel),
		Metadata: snapshot,
	}

	return output, nil

}

// GetSnapshotDownloadLink return download link for a snapshot
func (p *Processor) GetSnapshotDownloadLink(snapshotName string) (string, error) {
	link, err := p.SnapshotProcessor.GetDownloadLink(snapshotName)
	if err != nil {
		return "", err
	}

	return link, nil
}

// DeleteSnapshot deletes a snapshot
func (p *Processor) DeleteSnapshot(snapshotName string) error {
	err := p.SnapshotProcessor.DeleteSnapshot(snapshotName)
	if err != nil {
		return err
	}

	return nil
}

// DeleteAppSnapshots deletes all snapshot of given app
func (p *Processor) DeleteAppSnapshots() error {
	err := p.SnapshotProcessor.DeleteAppSnapshots(p.AppName)
	if err != nil {
		return err
	}

	return nil
}

// Returns active technology in the app
func (p *Processor) GetActiveTech() (*containers.TechInfo, error) {
	container, err := p.getContainer()
	if err != nil {
		return nil, err
	}

	tech, err := container.GetActiveTech()
	if err != nil {
		return tech, err
	}

	return tech, nil
}