// +build !windows

package daemon

import (
	"fmt"
	"io/ioutil"
	"os"
	"os/exec"
	"strings"
)

const dockerExe = "/usr/local/bin/docker"
const dockerdExe = "/usr/local/bin/dockerd"

func startDaemon(daemon Daemon) {
	cmd := commandDaemon(daemon)
	if daemon.Debug {
		cmd.Stdout = os.Stdout
		cmd.Stderr = os.Stderr
	} else {
		cmd.Stdout = ioutil.Discard
		cmd.Stderr = ioutil.Discard
	}
	go func() {
		trace(cmd)
		cmd.Run()
	}()
}

// helper function to create the docker daemon command.
func commandDaemon(daemon Daemon) *exec.Cmd {
	args := []string{
		"--data-root", daemon.StoragePath,
		"--host=unix:///var/run/docker.sock",
	}

	if _, err := os.Stat("/etc/docker/default.json"); err == nil {
		args = append(args, "--seccomp-profile=/etc/docker/default.json")
	}

	if daemon.StorageDriver != "" {
		args = append(args, "-s", daemon.StorageDriver)
	}
	if daemon.Insecure && daemon.Registry != "" {
		args = append(args, "--insecure-registry", daemon.Registry)
	}
	if daemon.IPv6 {
		args = append(args, "--ipv6")
	}
	if len(daemon.Mirror) != 0 {
		args = append(args, "--registry-mirror", daemon.Mirror)
	}
	if len(daemon.Bip) != 0 {
		args = append(args, "--bip", daemon.Bip)
	}
	for _, dns := range daemon.DNS {
		args = append(args, "--dns", dns)
	}
	for _, dnsSearch := range daemon.DNSSearch {
		args = append(args, "--dns-search", dnsSearch)
	}
	if len(daemon.MTU) != 0 {
		args = append(args, "--mtu", daemon.MTU)
	}
	if daemon.Experimental {
		args = append(args, "--experimental")
	}
	return exec.Command(dockerdExe, args...)
}

// trace writes each command to stdout with the command wrapped in an xml
// tag so that it can be extracted and displayed in the logs.
func trace(cmd *exec.Cmd) {
	fmt.Fprintf(os.Stdout, "+ %s\n", strings.Join(cmd.Args, " "))
}