package ssh

import (
	"net"
	"os"
	"path/filepath"

	"golang.org/x/crypto/ssh"
	"golang.org/x/crypto/ssh/agent"
	"golang.org/x/crypto/ssh/knownhosts"
)

func Exec(cfg *ssh.ClientConfig, addr, cmd string) error {
	c, err := ssh.Dial("tcp", addr, cfg)
	if err != nil {
		return err
	}
	s, err := c.NewSession()
	defer s.Close()
	err = s.Run(cmd)
	if err != nil {
		return err
	}
	return nil
}

func NewClientConfig() (*ssh.ClientConfig, error) {
	c, err := net.Dial("unix", os.Getenv("SSH_AUTH_SOCK"))
	if err != nil {
		return nil, err
	}
	ac := agent.NewClient(c)
	hkc, err := knownhosts.New(filepath.Join(os.Getenv("HOME"), ".ssh", "known_hosts"))
	if err != nil {
		return nil, err
	}
	signers, err := ac.Signers()
	if err != nil {
		return nil, err
	}
	am := make([]ssh.AuthMethod, 0, len(signers))
	for _, signer := range signers {
		am = append(am, ssh.PublicKeys(signer))
	}
	return &ssh.ClientConfig{
		User:              "root",
		HostKeyCallback:   hkc,
		Auth:              am,
		HostKeyAlgorithms: []string{ssh.KeyAlgoED25519},
	}, nil
}