package git

import (
	"golang.org/x/crypto/ssh"
	"gopkg.in/src-d/go-git.v4"
	"gopkg.in/src-d/go-git.v4/plumbing"
	gitSsh "gopkg.in/src-d/go-git.v4/plumbing/transport/ssh"
	"net/url"
	"strings"
)

// Service represents a service for managing Git.
type Service struct{}

// NewService initializes a new service.
func NewService(dataStorePath string) (*Service, error) {
	service := &Service{}

	return service, nil
}

// ClonePublicRepository clones a public git repository using the specified URL in the specified
// destination folder.
func (service *Service) ClonePublicRepository(repositoryURL, referenceName string, destination string) error {
	return cloneRepository(repositoryURL, referenceName, destination)
}

// ClonePrivateRepositoryWithBasicAuth clones a private git repository using the specified URL in the specified
// destination folder. It will use the specified username and password for basic HTTP authentication.
func (service *Service) ClonePrivateRepositoryWithBasicAuth(repositoryURL, referenceName string, destination, username, password string) error {
	credentials := username + ":" + url.PathEscape(password)
	repositoryURL = strings.Replace(repositoryURL, "://", "://"+credentials+"@", 1)
	return cloneRepository(repositoryURL, referenceName, destination)
}

func cloneRepository(repositoryURL, referenceName string, destination string) error {
	options := &git.CloneOptions{
		URL: repositoryURL,
	}

	if referenceName != "" {
		options.ReferenceName = plumbing.ReferenceName(referenceName)
	}

	_, err := git.PlainClone(destination, false, options)
	return err
}

// ClonePrivateRepositoryWithDeploymentKey clones a private git repository using the specified URL in the specified
// destination folder. It will use the specified deployment key for SSH based authentication
func (service *Service) ClonePrivateRepositoryWithDeploymentKey(repositoryURL, referenceName string, destination string, privateKeyPem []byte) error {
	signer, _ := ssh.ParsePrivateKey(privateKeyPem)
	auth := &gitSsh.PublicKeys{
		User:   "git",
		Signer: signer,
		HostKeyCallbackHelper: gitSsh.HostKeyCallbackHelper{
			HostKeyCallback: ssh.InsecureIgnoreHostKey(),
		},
	}

	repositoryURL = strings.Replace(repositoryURL, "https://", "git@", 1)
	repositoryURL = strings.Replace(repositoryURL, "github.com/", "github.com:", 1)
	repositoryURL += ".git"

	options := &git.CloneOptions{
		URL:               repositoryURL,
		RecurseSubmodules: git.DefaultSubmoduleRecursionDepth,
		Auth:              auth,
	}

	if referenceName != "" {
		options.ReferenceName = plumbing.ReferenceName(referenceName)
	}

	_, err := git.PlainClone(destination, false, options)
	return err
}