package containers

import (
	"bytes"
	"errors"
	"fmt"
	"log"
	"path"
	"strconv"
	"strings"

	"github.com/rosti-cz/node-api/apps"
	"github.com/rosti-cz/node-api/detector"
)

// username in the containers under which all containers run
const appUsername = "app"
const owner = "app:app"
const passwordFile = "/srv/.rosti"
const deployKeyType = "ed25519"
const deployKeyPrefix = "rosti_deploy"

// Structure containing info about technology and its version
type TechInfo struct {
	Tech    string `json:"tech"`
	Version string `json:"version"`
}

// Process contains info about background application usually running in supervisor
type Process struct {
	Name  string `json:"name"`
	State string `json:"state"`
}

// Current status of the container
type ContainerStatus struct {
	Status    string `json:"status"`
	OOMKilled bool   `json:"oom_killed"`
}

// Container extends App struct from App
type Container struct {
	App        *apps.App `json:"app"`
	DockerSock string    `json:"-"`
	BindIPHTTP string    `json:"-"`
	BindIPSSH  string    `json:"-"`
	AppsPath   string    `json:"-"`
}

func (c *Container) getDriver() *Driver {
	driver := &Driver{
		DockerSock: c.DockerSock,
		BindIPHTTP: c.BindIPHTTP,
		BindIPSSH:  c.BindIPSSH,
	}
	return driver
}

// volumeHostPath each container has one volume mounted into it,
func (c *Container) volumeHostPath() string {
	return path.Join(c.AppsPath, c.App.Name)
}

// GetRawResourceStats returns RAW CPU and memory usage directly from Docker API
func (c *Container) GetRawResourceStats() (int64, int, error) {
	driver := c.getDriver()
	cpu, memory, err := driver.RawStats(c.App.Name)
	return cpu, memory, err
}

// GetState returns app state object with populated state fields
func (c *Container) GetState() (*apps.AppState, error) {
	status, err := c.Status()
	if err != nil {
		return nil, err
	}

	// TODO: this implementation takes more than one hour for 470 containers. It needs to be implemented differently.
	// cpu, memory, err := c.ResourceUsage()
	// if err != nil {
	// 	return nil, err
	// }

	bytes, inodes, err := c.DiskUsage()
	if err != nil {
		return nil, err
	}

	processes, err := c.GetSystemProcesses()
	if err != nil {
		return nil, err
	}

	flags, err := detector.Check(processes)
	if err != nil {
		return nil, err
	}

	state := apps.AppState{
		State:     status.Status,
		OOMKilled: status.OOMKilled,
		// CPUUsage:        cpu,
		// MemoryUsage:     memory,
		CPUUsage:        -1.0,
		MemoryUsage:     -1.0,
		DiskUsageBytes:  bytes,
		DiskUsageInodes: inodes,
		Flags:           flags,
	}

	return &state, nil
}

// Status returns state of the container
// Possible values: running, exited (stopped), no-container, unknown
func (c *Container) Status() (ContainerStatus, error) {
	status := ContainerStatus{
		Status: "unknown",
	}

	driver := c.getDriver()
	containerStatus, err := driver.Status(c.App.Name)
	if err != nil && err.Error() == "no container found" {
		return ContainerStatus{Status: "no-container"}, nil
	}
	if err != nil {
		return status, err
	}

	return containerStatus, nil
}

// DiskUsage returns number of bytes and inodes used by the container in it's mounted volume
func (c *Container) DiskUsage() (int, int, error) {
	return du(c.volumeHostPath())
}

// ResourceUsage returns amount of memory in B and CPU in % that the app occupies
func (c *Container) ResourceUsage() (float64, int, error) {
	driver := c.getDriver()

	cpu, memory, err := driver.Stats(c.App.Name)
	if err != nil {
		return 0.0, 0, err
	}

	return cpu, memory, nil
}

// Create creates the container
func (c *Container) Create() error {
	driver := c.getDriver()
	_, err := driver.Create(
		c.App.Name,
		c.App.Image,
		c.volumeHostPath(),
		c.App.HTTPPort,
		c.App.SSHPort,
		c.App.CPU,
		c.App.Memory,
		[]string{},
	)

	return err
}

// Start starts the container
func (c *Container) Start() error {
	driver := c.getDriver()

	return driver.Start(c.App.Name)
}

// Stop stops the container
func (c *Container) Stop() error {
	driver := c.getDriver()

	return driver.Stop(c.App.Name)
}

// Restart restarts the container
func (c *Container) Restart() error {
	driver := c.getDriver()

	err := driver.Stop(c.App.Name)
	if err != nil {
		return err
	}

	return driver.Start(c.App.Name)
}

// Destroy removes the container but keeps the data so it can be created again
func (c *Container) Destroy() error {
	driver := c.getDriver()

	return driver.Remove(c.App.Name)
}

// Delete removes both data and the container
func (c *Container) Delete() error {
	status, err := c.Status()
	if err != nil {
		return err
	}

	// It's questionable to have this here. The problem is this method
	// does two things, deleting the container and the data and when
	// the deleted container doesn't exist we actually don't care
	// and we can continue to remove the data.
	if status.Status != "no-container" {
		err = c.Destroy()
		if err != nil {
			return err
		}
	}

	volumePath := path.Join(c.AppsPath, c.App.Name)
	err = removeDirectory(volumePath)
	if err != nil {
		log.Println(err)
	}

	return nil
}

// SetPassword configures password for system user app in the container
func (c *Container) SetPassword(password string) error {
	driver := c.getDriver()

	_, err := driver.Exec(c.App.Name, []string{"chpasswd"}, appUsername+":"+password, []string{}, false)
	if err != nil {
		return err
	}

	_, err = driver.Exec(c.App.Name, []string{"tee", passwordFile}, password, []string{}, false)
	if err != nil {
		return err
	}

	return err
}

// Generate SSH keys and copies it into authorized keys
// Returns true if the key was generated in this call and error if there is any.
// The container has to run for this to work.
func (c *Container) GenerateDeploySSHKeys() (bool, error) {
	driver := c.getDriver()

	privateKey, pubKey, _ := c.GetDeploySSHKeys()
	if privateKey != "" || pubKey != "" {
		return false, nil
	}

	_, err := driver.Exec(c.App.Name, []string{"mkdir", "-p", "/srv/.ssh"}, "", []string{}, true)
	if err != nil {
		return false, err
	}

	_, err = driver.Exec(c.App.Name, []string{"ssh-keygen", "-t", deployKeyType, "-f", "/srv/.ssh/" + deployKeyPrefix + "_id_" + deployKeyType, "-P", ""}, "", []string{}, true)
	if err != nil {
		return false, err
	}

	_, err = driver.Exec(c.App.Name, []string{"chown", "app:app", "-R", "/srv/.ssh"}, "", []string{}, true)
	if err != nil {
		return false, err
	}

	return true, nil
}

// Generate SSH keys and copies it into authorized keys
// Return private key, public key and error.
// The container has to run for this to work.
func (c *Container) GetDeploySSHKeys() (string, string, error) {
	driver := c.getDriver()

	privateKey, err := driver.Exec(c.App.Name, []string{"cat", "/srv/.ssh/" + deployKeyPrefix + "_id_" + deployKeyType}, "", []string{}, true)
	if err != nil {
		return "", "", err
	}
	pubKey, err := driver.Exec(c.App.Name, []string{"cat", "/srv/.ssh/" + deployKeyPrefix + "_id_" + deployKeyType + ".pub"}, "", []string{}, true)
	if err != nil {
		return "", "", err
	}

	if privateKey != nil && pubKey != nil && !bytes.Contains(*privateKey, []byte("No such file")) && !bytes.Contains(*pubKey, []byte("No such file")) {
		return string(*privateKey), string(*pubKey), nil
	}

	return "", "", nil
}

// Return host key without hostname
// The container has to run for this to work.
func (c *Container) GetHostKey() (string, error) {
	driver := c.getDriver()

	hostKeyRaw, err := driver.Exec(c.App.Name, []string{"ssh-keyscan", "localhost"}, "", []string{}, true)
	if err != nil {
		return "", err
	}

	// Loop over lines and search for localhost ssh
	line := ""
	if hostKeyRaw != nil {
		for _, line = range strings.Split(string(*hostKeyRaw), "\n") {
			if strings.HasPrefix(line, "localhost ssh") {
				line = strings.TrimSpace(line)
				break
			}
		}
	}

	if line == "" {
		return "", errors.New("key not found")
	}

	parts := strings.SplitN(line, " ", 2)
	if len(parts) > 1 {
		return parts[1], nil
	}

	return "", errors.New("key not found")
}

// Append text to a file in the container
func (c *Container) AppendFile(filename string, text string, mode string) error {
	driver := c.getDriver()

	directory := path.Dir(filename)

	_, err := driver.Exec(c.App.Name, []string{"mkdir", "-p", directory}, "", []string{}, false)
	if err != nil {
		return err
	}

	_, err = driver.Exec(c.App.Name, []string{"tee", "-a", filename}, text, []string{}, false)
	if err != nil {
		return err
	}

	_, err = driver.Exec(c.App.Name, []string{"chmod", mode, filename}, "", []string{}, false)
	if err != nil {
		return err
	}

	_, err = driver.Exec(c.App.Name, []string{"chown", owner, directory}, "", []string{}, false)
	if err != nil {
		return err
	}

	_, err = driver.Exec(c.App.Name, []string{"chown", owner, filename}, "", []string{}, false)
	if err != nil {
		return err
	}

	return nil
}

// SetAppPort changes application port in the container
func (c *Container) SetAppPort(port int) error {
	driver := c.getDriver()

	_, err := driver.Exec(
		c.App.Name,
		[]string{
			"sed",
			"-i",
			"s+proxy_pass[ ]*http://127.0.0.1:8080/;+proxy_pass         http://127.0.0.1:" + strconv.Itoa(port) + "/;+g",
			"/srv/conf/nginx.d/app.conf",
		},
		"",
		[]string{},
		false,
	)
	if err != nil {
		return err
	}

	return err
}

// SetFileContent uploads text into a file inside the container. It's greate for uploading SSH keys.
// The method creates the diretory where the file is located and sets mode of the final file
func (c *Container) SetFileContent(filename string, text string, mode string) error {
	driver := c.getDriver()

	directory := path.Dir(filename)

	_, err := driver.Exec(c.App.Name, []string{"mkdir", "-p", directory}, "", []string{}, false)
	if err != nil {
		return err
	}

	_, err = driver.Exec(c.App.Name, []string{"tee", filename}, text, []string{}, false)
	if err != nil {
		return err
	}

	_, err = driver.Exec(c.App.Name, []string{"chown", owner, directory}, "", []string{}, false)
	if err != nil {
		return err
	}

	_, err = driver.Exec(c.App.Name, []string{"chown", owner, filename}, "", []string{}, false)
	if err != nil {
		return err
	}

	_, err = driver.Exec(c.App.Name, []string{"chmod", mode, filename}, "", []string{}, false)
	return err
}

// SetTechnology prepares container for given technology (Python, PHP, Node.js, ...)
// Where tech can be php, python or node and latest available version is used.
// If version is empty string default version will be used.
func (c *Container) SetTechnology(tech string, version string) error {
	driver := c.getDriver()

	var err error

	// TODO: script injection here?
	var output *[]byte
	if version == "" {
		output, err = driver.Exec(c.App.Name, []string{"su", "app", "-c", "rosti " + tech}, "", []string{}, false)
	} else {
		output, err = driver.Exec(c.App.Name, []string{"su", "app", "-c", "rosti " + tech + " " + version}, "", []string{}, false)
	}

	log.Printf("DEBUG: enable tech for %s output: %s", c.App.Name, string(*output))

	return err
}

// GetProcessList returns list of processes managed by supervisor.
func (c *Container) GetProcessList() ([]Process, error) {
	driver := c.getDriver()

	processes := []Process{}

	stdouterr, err := driver.Exec(c.App.Name, []string{"supervisorctl", "status"}, "", []string{}, true)
	if err != nil {
		return processes, nil
	}

	trimmed := strings.TrimSpace(string(*stdouterr))
	for _, row := range strings.Split(trimmed, "\n") {
		fields := strings.Fields(row)
		if len(fields) > 2 {
			processes = append(processes, Process{
				Name:  fields[0],
				State: fields[1],
			})
		}
	}

	return processes, nil
}

// Restarts supervisord process
func (c *Container) RestartProcess(name string) error {
	driver := c.getDriver()

	_, err := driver.Exec(c.App.Name, []string{"supervisorctl", "restart", name}, "", []string{}, false)
	return err
}

// Starts supervisord process
func (c *Container) StartProcess(name string) error {
	driver := c.getDriver()

	_, err := driver.Exec(c.App.Name, []string{"supervisorctl", "start", name}, "", []string{}, false)
	return err
}

// Stops supervisord process
func (c *Container) StopProcess(name string) error {
	driver := c.getDriver()

	_, err := driver.Exec(c.App.Name, []string{"supervisorctl", "stop", name}, "", []string{}, false)
	return err
}

// Reread supervisord config
func (c *Container) ReloadSupervisor() error {
	driver := c.getDriver()

	_, err := driver.Exec(c.App.Name, []string{"supervisorctl", "reread"}, "", []string{}, false)
	if err != nil {
		return err
	}

	_, err = driver.Exec(c.App.Name, []string{"supervisorctl", "update"}, "", []string{}, false)
	if err != nil {
		return err
	}

	return err
}

// GetSystemProcesses return list of running system processes
func (c *Container) GetSystemProcesses() ([]string, error) {
	driver := c.getDriver()

	processes, err := driver.GetProcesses(c.App.Name)
	return processes, err
}

// GetPrimaryTech returns primary tech configured in the container.
func (c *Container) GetPrimaryTech() (apps.AppTech, error) {
	tech := apps.AppTech{}

	driver := c.getDriver()

	stdouterr, err := driver.Exec(c.App.Name, []string{"readlink", "/srv/bin/primary_tech"}, "", []string{}, true)
	if err != nil {
		// in case there is an error just return empty response
		return tech, nil
	}

	if len(string(*stdouterr)) > 0 {
		parts := strings.Split(string(*stdouterr), "/")
		if len(parts) == 5 {
			rawTech := parts[3]
			techParts := strings.Split(rawTech, "-")
			if len(techParts) != 2 {
				return tech, errors.New("wrong number of tech parts")
			}
			return apps.AppTech{
				Name:    techParts[0],
				Version: techParts[1],
			}, nil
		}
	}

	// Probably single technology image in case the output is empty
	return tech, nil
}

// GetTechs returns all techs available in the container
func (c *Container) GetTechs() (apps.AppTechs, error) {
	techs := apps.AppTechs{}

	driver := c.getDriver()

	stdouterr, err := driver.Exec(c.App.Name, []string{"ls", "/opt"}, "", []string{}, true)
	if err != nil {
		// in case there is an error just return empty response
		return techs, nil
	}

	// Check if /opt/techs exists
	if !strings.Contains(string(*stdouterr), "techs") {
		return techs, nil
	}

	stdouterr, err = driver.Exec(c.App.Name, []string{"ls", "/opt/techs"}, "", []string{}, true)
	if err != nil {
		// in case there is an error just return empty response
		return techs, nil
	}

	// If the directory doesn't exist it's single technology image
	if strings.Contains(string(*stdouterr), "No such file or directory") {
		return techs, nil
	}

	techsRaw := strings.Fields(string(*stdouterr))
	for _, techRaw := range techsRaw {
		techParts := strings.Split(techRaw, "-")
		if len(techParts) == 2 {
			techs = append(techs, apps.AppTech{
				Name:    techParts[0],
				Version: techParts[1],
			})
		} else {
			return techs, fmt.Errorf("one of the tech has wrong number of parts (%s)", techRaw)
		}
	}

	return techs, nil
}

// Returns info about active technology
func (c *Container) GetActiveTech() (*TechInfo, error) {
	info, err := getTechAndVersion(path.Join(c.volumeHostPath(), "bin", "primary_tech"))
	if err != nil {
		return info, err
	}

	return info, nil
}