package main

import (
	"bytes"
	"fmt"
	"log"
	"os"
	"os/exec"
	"strings"
	"text/template"
)

type Services struct {
	cfg config
}

func NewServices(cfg config) *Services {
	return &Services{cfg: cfg}
}

func (s *Services) AddPrivateKey() error {
	log.Println("Adding private key")

	if err := os.MkdirAll(os.ExpandEnv("${HOME}/.ssh"), 0700); err != nil {
		return err
	}

	if err := writeFile(`${HOME}/.ssh/id_rsa`, s.cfg.PrivateKey, 0400); err != nil {
		return err
	}

	return nil
}

func (s *Services) ConfigureSSH() error {
	log.Println("Configuring SSH")

	var bfr bytes.Buffer
	if err := sshConfigTemplate.Execute(&bfr, struct {
		Cfg  config
		Home string
	}{
		Cfg:  s.cfg,
		Home: os.Getenv("HOME"),
	}); err != nil {
		return err
	}

	if err := writeFile(`${HOME}/.ssh/config`, bfr.String(), 0400); err != nil {
		return err
	}

	return nil
}

func (s *Services) PushRepository() error {
	sshUrl := fmt.Sprintf(`dokku@%v`, s.cfg.HostName)
	remoteUrl := fmt.Sprintf(`ssh://%v:22/%v`, sshUrl, s.cfg.AppName)

	log.Println("Testing Dokku SSH connection")
	if err := runCmd("ssh", sshUrl, "version"); err != nil {
		return err
	}

	log.Println("SSH connection good. Pushing repository")
	if err := runCmd("git", "remote", "add", "dokku", remoteUrl); err != nil {
		return err
	}

	sourceBranch := s.cfg.LocalBranch
	if sourceBranch == "" {
		// Get the current ref
		ref, err := runCmdExpectingOutput("git", "rev-parse", "--abbrev-ref", "HEAD")
		if err != nil {
			return err
		}

		sourceBranch = strings.TrimSpace(ref)
	}
	remoteBranch := s.cfg.RemoteBranch
	if remoteBranch == "" {
		remoteBranch = sourceBranch
	}

	branchArg := sourceBranch
	if sourceBranch != remoteBranch {
		branchArg = fmt.Sprintf("%v:%v", sourceBranch, remoteBranch)
	}

	if err := runCmd("git", "push", "dokku", branchArg); err != nil {
		return err
	}

	return nil
}

func runCmd(cmd ...string) error {
	log.Printf(" .. [exec] %v", strings.Join(cmd, " "))
	e := exec.Command(cmd[0], cmd[1:]...)
	e.Stderr = os.Stderr
	e.Stdout = os.Stdout
	return e.Run()
}

func runCmdExpectingOutput(cmd ...string) (string, error) {
	log.Printf(" .. [exec] %v", strings.Join(cmd, " "))
	e := exec.Command(cmd[0], cmd[1:]...)
	e.Stderr = os.Stderr
	res, err := e.Output()
	if err != nil {
		return "", err
	}
	return string(res), nil
}

func writeFile(path string, content string, mode os.FileMode) error {
	fullPath := os.ExpandEnv(path)
	log.Printf(" .. [file] %v (%v bytes)", fullPath, len(content))

	return os.WriteFile(fullPath, []byte(content), mode)
}

var (
	sshConfigTemplate = template.Must(template.New("ssh-config").Parse(`
Host *
  StrictHostKeyChecking no

Host {{.Cfg.HostName}}
  HostName {{.Cfg.HostName}}
  User dokku
  IdentityFile {{.Home}}/.ssh/id_rsa
`))
)