#!/usr/bin/env gjs

//

// Copyright (C) 2014 Colin Walters <walters@verbum.org>

//

// SPDX-License-Identifier: LGPL-2.0+

//

// This library is free software; you can redistribute it and/or

// modify it under the terms of the GNU Lesser General Public

// License as published by the Free Software Foundation; either

// version 2 of the License, or (at your option) any later version.

//

// This library 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

// Lesser General Public License for more details.

//

// You should have received a copy of the GNU Lesser General Public

// License along with this library; if not, write to the

// Free Software Foundation, Inc., 59 Temple Place - Suite 330,

// Boston, MA 02111-1307, USA.

const GLib = imports.gi.GLib;

const Gio = imports.gi.Gio;

const OSTree = imports.gi.OSTree;

let repoPathArg = ARGV[0];

let refToCorrupt = ARGV[1];

let repo = OSTree.Repo.new(Gio.File.new_for_path(repoPathArg));

repo.open(null);

function listObjectChecksumsRecurse(dir, allObjects) {

    dir.ensure_resolved();

    allObjects[dir.tree_get_contents_checksum() + '.dirtree'] = true;

    allObjects[dir.get_checksum() + '.dirmeta'] = true;

    let e = dir.enumerate_children('standard::name,standard::type', 0, null);

    let info;

    while ((info = e.next_file(null)) != null) {

	let child = e.get_child(info);

	child.ensure_resolved();

	print(info.get_name() + " is " + info.get_file_type());

	if (info.get_file_type() == Gio.FileType.DIRECTORY) {

	    listObjectChecksumsRecurse(child, allObjects);

	} else {

	    allObjects[child.get_checksum() + '.filez'] = true;

	}

    } 

    e.close(null);

} 

let [,root,commit] = repo.read_commit(refToCorrupt, null);

let allObjects = {};

allObjects[commit + '.commit'] = true;

listObjectChecksumsRecurse(root, allObjects);

let i = 0;

for (let v in allObjects) 

    i++;

print("commit " + commit + " refers to " + i + " objects");

let offset = GLib.random_int_range(0, i);

let objectToCorrupt = null;

for (let v in allObjects) {

    if (offset <= 0) {

	objectToCorrupt = v;

	break;

    }

    offset--;

}

print("Choosing " + objectToCorrupt + " to corrupt");

let loosePath = repo.get_path().resolve_relative_path('objects/' + objectToCorrupt.substring(0, 2) + "/" + objectToCorrupt.substring(2));

let iostream = loosePath.open_readwrite(null);

let info = iostream.query_info('standard::size', null);

let size = info.get_size();

let datain = Gio.DataInputStream.new(iostream.get_input_stream());

let dataout = Gio.DataOutputStream.new(iostream.get_output_stream());

let bytesToChange = 10;

let status = "";

var bytesChanged = {}

for (i = 0; i < bytesToChange; i++) {

    let byteOffsetToCorrupt;

    do {

        byteOffsetToCorrupt = GLib.random_int_range(0, size);

    } while (byteOffsetToCorrupt in bytesChanged);

    iostream.seek(byteOffsetToCorrupt, GLib.SeekType.SET, null);

    let inbyte = datain.read_byte(null);

    let outbyte = (inbyte + 1) % 255;

    dataout.put_byte(outbyte, null);

    bytesChanged[byteOffsetToCorrupt] = byteOffsetToCorrupt;

    status += "Changed byte offset " + byteOffsetToCorrupt + " from " + inbyte + " to " + outbyte + "\n";

}

dataout.flush(null);

iostream.close(null);

print(status);

let successFile = Gio.File.new_for_path('corrupted-status.txt');

successFile.replace_contents(status, null, false, 0, null);