package pkg

import (
	urlpkg "net/url"
	"path"
	"regexp"
	"strings"

	"github.com/pkg/errors"
)

// scpSyntax matches the SCP-like addresses used by the ssh procotol (eg, [user@]host.xz:path/to/repo.git/).
// See: https://golang.org/src/cmd/go/internal/get/vcs.go
var scpSyntax = regexp.MustCompile(`^([a-zA-Z0-9_]+)@([a-zA-Z0-9._-]+):(.*)$`)

func URLToPath(rawurl string) (repoPath string, err error) {
	url, err := parseURL(rawurl)
	if err != nil {
		return "", err
	}

	// remove port numbers from host
	repoHost := strings.Split(url.Host, ":")[0]

	// remove trailing ".git" from repo name
	repoPath = path.Join(repoHost, url.Path)
	repoPath = strings.TrimSuffix(repoPath, ".git")

	// remove tilde (~) char from username
	repoPath = strings.ReplaceAll(repoPath, "~", "")

	return repoPath, nil
}

func parseURL(rawurl string) (url *urlpkg.URL, err error) {
	// If rawurl matches SCP-like syntax, convert it into a URL.
	// eg, "git@github.com:user/repo" becomes "ssh://git@github.com/user/repo".
	if m := scpSyntax.FindStringSubmatch(rawurl); m != nil {
		url = &urlpkg.URL{
			Scheme: "ssh",
			User:   urlpkg.User(m[1]),
			Host:   m[2],
			Path:   m[3],
		}
	} else {
		url, err = urlpkg.Parse(rawurl)
		if err != nil {
			return nil, errors.Wrap(err, "Failed parsing URL")
		}
	}

	if url.Host == "" && url.Path == "" {
		return nil, errors.New("Parsed URL is empty")
	}

	return url, nil
}