/*
goredo -- djb's redo implementation on pure Go
Copyright (C) 2020-2021 Sergey Matveev <stargrave@stargrave.org>

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, version 3 of the License.

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/>.
*/

// Inode metainformation

package main

import (
	"errors"
	"os"
	"strconv"

	"go.cypherpunks.ru/recfile"
	"golang.org/x/sys/unix"
)

const EnvInodeNoTrust = "REDO_INODE_NO_TRUST"

var InodeTrust bool = false

type Inode struct {
	Size      int64
	CtimeSec  int64
	CtimeNsec int64
}

func (our *Inode) Equals(their *Inode) bool {
	return (our.Size == their.Size) &&
		(our.CtimeSec == their.CtimeSec) &&
		(our.CtimeNsec == their.CtimeNsec)
}

func (inode *Inode) RecfileFields() []recfile.Field {
	return []recfile.Field{
		{Name: "Size", Value: strconv.FormatInt(inode.Size, 10)},
		{Name: "CtimeSec", Value: strconv.FormatInt(inode.CtimeSec, 10)},
		{Name: "CtimeNsec", Value: strconv.FormatInt(inode.CtimeNsec, 10)},
	}
}

func inodeFromFile(fd *os.File) (*Inode, error) {
	var fi os.FileInfo
	fi, err := fd.Stat()
	if err != nil {
		return nil, err
	}
	var stat unix.Stat_t
	err = unix.Fstat(int(fd.Fd()), &stat)
	if err != nil {
		return nil, err
	}
	sec, nsec := stat.Ctim.Unix()
	return &Inode{Size: fi.Size(), CtimeSec: sec, CtimeNsec: nsec}, nil
}

func inodeFromRec(m map[string]string) (*Inode, error) {
	size := m["Size"]
	ctimeSec := m["CtimeSec"]
	ctimeNsec := m["CtimeNsec"]
	if size == "" {
		return nil, errors.New("Size is missing")
	}
	if ctimeSec == "" {
		return nil, errors.New("CtimeSec is missing")
	}
	if ctimeNsec == "" {
		return nil, errors.New("CtimeNsec is missing")
	}
	inode := Inode{}
	var err error
	inode.Size, err = strconv.ParseInt(size, 10, 64)
	if err != nil {
		return nil, err
	}
	inode.CtimeSec, err = strconv.ParseInt(ctimeSec, 10, 64)
	if err != nil {
		return nil, err
	}
	inode.CtimeNsec, err = strconv.ParseInt(ctimeNsec, 10, 64)
	if err != nil {
		return nil, err
	}
	return &inode, nil
}