/*
Copyright 2016 The Kubernetes Authors 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 provision

import (
	"bytes"
	"fmt"
	"path"
	"text/template"
	"time"

	"github.com/docker/machine/libmachine/auth"
	"github.com/docker/machine/libmachine/drivers"
	"github.com/docker/machine/libmachine/engine"
	"github.com/docker/machine/libmachine/log"
	"github.com/docker/machine/libmachine/provision"
	"github.com/docker/machine/libmachine/provision/pkgaction"
	"github.com/docker/machine/libmachine/swarm"
	"k8s.io/minikube/pkg/util"
)

type BuildrootProvisioner struct {
	provision.SystemdProvisioner
}

func init() {
	provision.Register("Buildroot", &provision.RegisteredProvisioner{
		New: NewBuildrootProvisioner,
	})
}

func NewBuildrootProvisioner(d drivers.Driver) provision.Provisioner {
	return &BuildrootProvisioner{
		provision.NewSystemdProvisioner("buildroot", d),
	}
}

func (p *BuildrootProvisioner) String() string {
	return "buildroot"
}

func (p *BuildrootProvisioner) GenerateDockerOptions(dockerPort int) (*provision.DockerOptions, error) {
	var engineCfg bytes.Buffer

	driverNameLabel := fmt.Sprintf("provider=%s", p.Driver.DriverName())
	p.EngineOptions.Labels = append(p.EngineOptions.Labels, driverNameLabel)

	engineConfigTmpl := `[Unit]
Description=Docker Application Container Engine
Documentation=https://docs.docker.com
After=network.target docker.socket
Requires=docker.socket

[Service]
Type=notify

# DOCKER_RAMDISK disables pivot_root in Docker, using MS_MOVE instead.
Environment=DOCKER_RAMDISK=yes
{{range .EngineOptions.Env}}Environment={{.}}
{{end}}
ExecStart=/usr/bin/docker daemon -H tcp://0.0.0.0:{{.DockerPort}} -H unix:///var/run/docker.sock --tlsverify --tlscacert {{.AuthOptions.CaCertRemotePath}} --tlscert {{.AuthOptions.ServerCertRemotePath}} --tlskey {{.AuthOptions.ServerKeyRemotePath}} {{ range .EngineOptions.Labels }}--label {{.}} {{ end }}{{ range .EngineOptions.InsecureRegistry }}--insecure-registry {{.}} {{ end }}{{ range .EngineOptions.RegistryMirror }}--registry-mirror {{.}} {{ end }}{{ range .EngineOptions.ArbitraryFlags }}--{{.}} {{ end }}
ExecReload=/bin/kill -s HUP $MAINPID

# Having non-zero Limit*s causes performance problems due to accounting overhead
# in the kernel. We recommend using cgroups to do container-local accounting.
LimitNOFILE=infinity
LimitNPROC=infinity
LimitCORE=infinity

# Uncomment TasksMax if your systemd version supports it.
# Only systemd 226 and above support this version.
TasksMax=infinity
TimeoutStartSec=0

# set delegate yes so that systemd does not reset the cgroups of docker containers
Delegate=yes

# kill only the docker process, not all processes in the cgroup
KillMode=process

[Install]
WantedBy=multi-user.target
`
	t, err := template.New("engineConfig").Parse(engineConfigTmpl)
	if err != nil {
		return nil, err
	}

	engineConfigContext := provision.EngineConfigContext{
		DockerPort:    dockerPort,
		AuthOptions:   p.AuthOptions,
		EngineOptions: p.EngineOptions,
	}

	t.Execute(&engineCfg, engineConfigContext)

	return &provision.DockerOptions{
		EngineOptions:     engineCfg.String(),
		EngineOptionsPath: p.DaemonOptionsFile,
	}, nil
}

func (p *BuildrootProvisioner) Package(name string, action pkgaction.PackageAction) error {
	return nil
}

func (p *BuildrootProvisioner) Provision(swarmOptions swarm.Options, authOptions auth.Options, engineOptions engine.Options) error {
	p.SwarmOptions = swarmOptions
	p.AuthOptions = authOptions
	p.EngineOptions = engineOptions

	log.Debugf("setting hostname %q", p.Driver.GetMachineName())
	if err := p.SetHostname(p.Driver.GetMachineName()); err != nil {
		return err
	}

	p.AuthOptions = setRemoteAuthOptions(p)
	log.Debugf("set auth options %+v", p.AuthOptions)

	log.Debugf("setting up certificates")

	configureAuth := func() error {
		if err := provision.ConfigureAuth(p); err != nil {
			return &util.RetriableError{Err: err}
		}
		return nil
	}

	err := util.RetryAfter(5, configureAuth, time.Second*10)
	if err != nil {
		log.Debugf("Error configuring auth during provisioning %v", err)
		return err
	}

	return nil
}

func setRemoteAuthOptions(p provision.Provisioner) auth.Options {
	dockerDir := p.GetDockerOptionsDir()
	authOptions := p.GetAuthOptions()

	// due to windows clients, we cannot use filepath.Join as the paths
	// will be mucked on the linux hosts
	authOptions.CaCertRemotePath = path.Join(dockerDir, "ca.pem")
	authOptions.ServerCertRemotePath = path.Join(dockerDir, "server.pem")
	authOptions.ServerKeyRemotePath = path.Join(dockerDir, "server-key.pem")

	return authOptions
}
