package gitctl

import (
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"golang.org/x/crypto/ssh"
)

type localKey struct {
	Filename    string
	KeyType     string
	Fingerprint string
	Comment     string
	Line        string
	Registered  bool
}

func scanLocalSSHKeys(registered map[string]bool) ([]localKey, error) {
	home, err := os.UserHomeDir()
	if err != nil {
		return nil, fmt.Errorf("find home dir: %w", err)
	}
	pubs, err := filepath.Glob(filepath.Join(home, ".ssh", "*.pub"))
	if err != nil {
		return nil, fmt.Errorf("scan ~/.ssh: %w", err)
	}
	out := make([]localKey, 0, len(pubs))
	for _, path := range pubs {
		raw, err := os.ReadFile(path)
		if err != nil {
			continue
		}
		key, comment, _, _, err := ssh.ParseAuthorizedKey(raw)
		if err != nil {
			continue
		}
		line := strings.TrimSpace(string(ssh.MarshalAuthorizedKey(key)))
		if comment != "" {
			line += " " + comment
		}
		fp := ssh.FingerprintSHA256(key)
		out = append(out, localKey{
			Filename:    filepath.Base(path),
			KeyType:     key.Type(),
			Fingerprint: fp,
			Comment:     comment,
			Line:        line,
			Registered:  registered[fp],
		})
	}
	return out, nil
}

func reconstructAuthorizedLine(marshaled string) (string, error) {
	key, err := ssh.ParsePublicKey([]byte(marshaled))
	if err != nil {
		return "", fmt.Errorf("reconstruct ssh key: %w", err)
	}
	return strings.TrimSpace(string(ssh.MarshalAuthorizedKey(key))), nil
}