package cmd

import (
	"fmt"
	"os/exec"
	"regexp"
	"strings"
)

// parseOwnerRepo splits "owner/repo" into its parts.
func parseOwnerRepo(s string) (owner, repo string, err error) {
	s = strings.TrimSuffix(strings.TrimSpace(s), ".git")
	parts := strings.Split(s, "/")
	if len(parts) != 2 || parts[0] == "" || parts[1] == "" {
		return "", "", fmt.Errorf("expected owner/repo, got %q", s)
	}
	return parts[0], parts[1], nil
}

// resolveRepo determines the target repo: an explicit --repo flag ("owner/repo")
// wins; otherwise it infers "owner/repo" from the git "origin" remote of the
// current directory.
func resolveRepo(flagRepo string) (owner, repo string, err error) {
	if flagRepo != "" {
		return parseOwnerRepo(flagRepo)
	}
	url, err := gitOriginURL()
	if err != nil {
		return "", "", fmt.Errorf("no --repo given and could not infer from git remote: %w", err)
	}
	o, r, err := ownerRepoFromRemote(url)
	if err != nil {
		return "", "", fmt.Errorf("could not parse owner/repo from remote %q: %w", url, err)
	}
	return o, r, nil
}

func gitOriginURL() (string, error) {
	out, err := exec.Command("git", "remote", "get-url", "origin").Output()
	if err != nil {
		return "", err
	}
	return strings.TrimSpace(string(out)), nil
}

// remotePathRe captures the trailing owner/repo of a git remote URL, whether
// http(s)://host/owner/repo(.git), ssh://git@host:port/owner/repo(.git), or
// git@host:owner/repo(.git).
var remotePathRe = regexp.MustCompile(`[:/]([^/:]+)/([^/]+?)(?:\.git)?/?$`)

func ownerRepoFromRemote(url string) (owner, repo string, err error) {
	m := remotePathRe.FindStringSubmatch(url)
	if m == nil {
		return "", "", fmt.Errorf("unrecognized remote URL")
	}
	return m[1], m[2], nil
}