// MsgSyncReq: install packages on the remote host (Debian)

// Copyright (C) 2021  Simon Ruderich
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package sync

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

	"ruderich.org/simon/safcm"
)

func (s *Sync) syncPackagesDebian() error {
	s.log.Debugf("packages: detected debian")

	installed, err := s.debianInstalledPackages()
	if err != nil {
		return err
	}

	s.log.Debugf("packages: checking %s",
		strings.Join(s.req.Packages, " "))
	var install []string
	for _, x := range s.req.Packages {
		if !installed[x] {
			install = append(install, x)
		}
	}
	if len(install) == 0 {
		return nil
	}

	for _, x := range install {
		s.resp.PackageChanges = append(s.resp.PackageChanges,
			safcm.PackageChange{
				Name: x,
			})
	}

	if s.req.DryRun {
		return nil
	}

	s.log.Verbosef("packages: installing %s", strings.Join(install, " "))
	cmd := exec.Command("/usr/bin/apt-get", append([]string{"install",
		// Don't require further acknowledgment; this won't perform
		// dangerous actions
		"--assume-yes",
		// Don't perform upgrades
		"--no-upgrade",
		// Nobody needs those
		"--no-install-recommends",
		// Don't overwrite existing config files
		"-o", "Dpkg::Options::=--force-confdef",
		"-o", "Dpkg::Options::=--force-confold",
	}, install...)...)
	cmd.Env = append(os.Environ(),
		// Don't ask questions during installation
		"DEBIAN_FRONTEND=noninteractive",
	)
	_, err = s.cmd.CombinedOutputCmd("packages", cmd)
	if err != nil {
		return err
	}

	return nil
}

func (s *Sync) debianInstalledPackages() (map[string]bool, error) {
	out, _, err := s.cmd.Run("packages",
		"/usr/bin/dpkg-query",
		"--show",
		`--showformat=${Status}\t${Package}\n`,
	)
	if err != nil {
		return nil, err
	}
	lines := strings.Split(strings.TrimSpace(string(out)), "\n")

	res := make(map[string]bool)
	for _, line := range lines {
		xs := strings.Split(line, "\t")
		if len(xs) != 2 {
			return nil, fmt.Errorf("invalid dpkg-query line %q",
				line)
		}
		// We only care if the package is currently successfully
		// installed (last two fields). If a package is on hold (first
		// field) this is fine as well.
		if strings.HasSuffix(xs[0], " ok installed") {
			res[xs[1]] = true
		}
	}
	return res, nil
}