package cli

import (
	"context"
	"fmt"
	"net/url"
	"os"
	"path/filepath"
	"strconv"
	"strings"

	"gitea.mynodes.xyz/ilker/llmgw/internal/onboard"
)

// copyBackup puts an archive where server.yaml's backup_copy_to says, and
// keeps as many there as here. It says each copy, and fails on the first
// that cannot be made.
func copyBackup(ctx context.Context, archive string, targets []string, key, knownHosts string, keep int, say func(string)) error {
	for _, t := range targets {
		if strings.HasPrefix(t, "ssh://") {
			if err := copyOverSSH(ctx, archive, t, key, knownHosts, keep); err != nil {
				return fmt.Errorf("%s: %w", t, err)
			}
		} else {
			if err := copyToDir(archive, t, keep); err != nil {
				return fmt.Errorf("%s: %w", t, err)
			}
		}
		say("copied to " + t)
	}
	return nil
}

func copyToDir(archive, dir string, keep int) error {
	if err := os.MkdirAll(dir, 0o700); err != nil {
		return err
	}
	b, err := os.ReadFile(archive) //nolint:gosec // the archive just written
	if err != nil {
		return err
	}
	final := filepath.Join(dir, filepath.Base(archive))
	if err := os.WriteFile(final+".part", b, 0o600); err != nil {
		return err
	}
	if err := os.Rename(final+".part", final); err != nil {
		return err
	}
	_, err = pruneBackups(dir, keep)
	return err
}

func copyOverSSH(ctx context.Context, archive, target, key, knownHosts string, keep int) error {
	u, err := url.Parse(target)
	if err != nil || u.User == nil || u.Host == "" || u.Path == "" {
		return fmt.Errorf("not ssh://user@host/path")
	}
	port := 22
	if p := u.Port(); p != "" {
		port, _ = strconv.Atoi(p)
	}
	b, err := os.ReadFile(archive) //nolint:gosec // the archive just written
	if err != nil {
		return err
	}
	c := &onboard.GoSSH{Addr: u.Hostname(), Port: port, User: u.User.Username(), KeyFile: key, KnownHosts: knownHosts}
	defer c.Close()
	dir, name := shellQuote(u.Path), shellQuote(filepath.Base(archive))
	// Written beside its name and renamed, then the oldest beyond keep
	// removed: only archives this command wrote, by their names.
	script := fmt.Sprintf(`set -e
umask 077
mkdir -p %[1]s
cat > %[1]s/%[2]s.part
mv %[1]s/%[2]s.part %[1]s/%[2]s
ls -1t %[1]s | grep -E '^llmgw-backup-.*\.tar\.gz(\.age)?$' | tail -n +%[3]d | while read -r f; do rm -f %[1]s/"$f"; done
`, dir, name, keep+1)
	if out, err := c.Run(ctx, script, b); err != nil {
		return fmt.Errorf("%w: %s", err, strings.TrimSpace(string(out)))
	}
	return nil
}

func shellQuote(s string) string { return "'" + strings.ReplaceAll(s, "'", `'\''`) + "'" }