package main

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

var (
	keyRE    = regexp.MustCompile(`^\s+([^\s]+)`)
	authorRE = regexp.MustCompile(`uid[^]]+]\s([^\s]+)\s<([^>]+)`)
)

func gpgKeys() ([]Identity, error) {
	cmd := exec.Command("gpg", "-k")
	out, err := cmd.Output()
	if err != nil {
		return nil, err
	}

	lines := strings.Split(string(out), "\n")
	if len(lines) < 2 {
		return nil, errors.New("no GPG keys found")
	}
	lines = lines[2:]

	idents := make([]Identity, 0)
	for idx := 0; idx < len(lines); idx += 5 {
		if len(lines) < idx+4 {
			break
		}

		author := authorRE.FindStringSubmatch(lines[idx+2])
		idents = append(idents, Identity{
			Name:  author[1],
			Email: author[2],
			Key:   keyRE.FindString(lines[idx+1]),
		})
	}

	return idents, nil
}