#!/usr/bin/env perl

# Copyright (c) 2026, rodolico
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# 1. Redistributions of source code must retain the above copyright notice, this
#    list of conditions and the following disclaimer.
#
# 2. Redistributions in binary form must reproduce the above copyright notice,
#    this list of conditions and the following disclaimer in the documentation
#    and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#
# updateConfigKeys - Sample script for updating configuration keys during sneakernet cleanup
#
# This script demonstrates how to programmatically update configuration keys in a YAML
# configuration file during the cleanup phase of the sneakernet process. It's particularly
# useful for updating sensitive values like encryption keys, hostnames, email addresses,
# and other configuration parameters that may need to be changed after a sneakernet
# transfer is complete.
#
# The script uses dot notation to reference nested configuration keys (e.g., 
# 'target.geli.poolname' or 'datasets.dataset1.target') and creates a timestamped
# backup before making any changes.
#
# FEATURES:
# - Update existing keys with new values
# - Delete keys by using 'DELETE' as the value
# - Create new nested keys if they don't exist
# - Automatic timestamped backup before modifications
#
# This is provided as a sample implementation that can be customized for specific
# cleanup requirements in sneakernet workflows.
#
# USAGE:
# Edit the @updates array in the script to specify the configuration keys you want
# to update or delete:
#   - To update: 'key.path=newvalue'
#   - To delete: 'key.path=DELETE'
#
# Then run the script to apply the changes to the configuration file.
#
# REQUIREMENTS:
# - Perl with YAML::Tiny module installed. This must be installed on the system where
#   the script is executed. (target system for sneakernet)
#

use strict;
use warnings;
use YAML::Tiny;
use Data::Dumper;
use File::Copy qw(copy);
use POSIX qw(strftime);

# YAML::Tiny wrapper functions
my $LoadFile = sub {
    my $yaml = YAML::Tiny->read($_[0]);
    return $yaml->[0];
};

my $DumpFile = sub {
    my ($file, $data) = @_;
    my $yaml = YAML::Tiny->new($data);
    $yaml->write($file);
};

# Configuration file path (set this variable)
my $configFile = 'sneakernet.conf.yaml';

# Result array to collect output messages
my @result;
my @errors;
my $caller = caller(); # Check if called from another script and, if not, prints updates to STDOUT
# if we are being called from sneakernet, get verbosity level, otherwise just set to 5
my $verbosityLevel = ($caller && defined $ZFS_Utils::verboseLoggingLevel) ? $ZFS_Utils::verboseLoggingLevel : 5;


# Array of key-value pairs in dot notation
# To update a key: 'key.path=newvalue'
# To delete a key: 'key.path=DELETE'
my @updates = (
    'debug=1',
    'dryrun=0',
    'source.hostname=production',
    'source.report.email=admin@example.com',
    'target.geli.poolname=newbackup',
    'datasets.dataset1.target=newbackup',
    # 'datasets.oldDataset=DELETE',  # Example: delete a key
);

# Create backup of the original file with timestamp
my $timestamp = strftime("%Y%m%d_%H%M%S", localtime);
my $backupFile = "$configFile.bak.$timestamp";
if (!copy($configFile, $backupFile)) {
    push @errors, "Failed to create backup: $!\n";
    goto RETURN;
}
push @result, "Created backup: $backupFile\n";

# Load the YAML configuration file
my $config = $LoadFile->($configFile);

if ( $verbosityLevel ) {
   push @result, "Original configuration:\n";
   push @result, Dumper($config);
   push @result, "\n" . "=" x 60 . "\n\n";
}

# Process each update
foreach my $update (@updates) {
    # Split the update into key path and value
    my ($keyPath, $value) = split(/=/, $update, 2);
    
    unless (defined $value) {
        push @errors, "Warning: Invalid format for update '$update'. Skipping.\n";
        next;
    }
    
    # Split the key path by dots
    my @keys = split(/\./, $keyPath);
    
    # Check if this is a deletion operation
    if ($value eq 'DELETE') {
        # Navigate to the parent hash
        my $current = $config;
        my $found = 1;
        for (my $i = 0; $i < @keys - 1; $i++) {
            my $key = $keys[$i];
            if (exists $current->{$key} && ref($current->{$key}) eq 'HASH') {
                $current = $current->{$key};
            } else {
                $found = 0;
                last;
            }
        }
        
        my $finalKey = $keys[-1];
        if ($found && exists $current->{$finalKey}) {
            my $oldValue = $current->{$finalKey};
            delete $current->{$finalKey};
            push @result, "Deleted: $keyPath\n";
            push @result, "  Old value: $oldValue\n\n";
        } else {
            push @errors, "Delete skipped (key not found): $keyPath\n\n";
        }
    } else {
        # Navigate/create the nested hash structure
        my $current = $config;
        for (my $i = 0; $i < @keys - 1; $i++) {
            my $key = $keys[$i];
            # Create the nested hash if it doesn't exist
            $current->{$key} = {} unless exists $current->{$key};
            $current = $current->{$key};
        }
        
        # Set the final value
        my $finalKey = $keys[-1];
        my $oldValue = exists $current->{$finalKey} ? $current->{$finalKey} : 'undef';
        $current->{$finalKey} = $value;
        
        push @result, "Updated: $keyPath\n";
        push @result, "  Old value: $oldValue\n";
        push @result, "  New value: $value\n\n";
    }
}

if ( $verbosityLevel > 2 ) {
   push @result, "=" x 60 . "\n\n";
   push @result, "Updated configuration:\n";
   push @result, Dumper($config);
}

# Save the updated configuration back to the file
$DumpFile->($configFile, $config);
push @result, "\nChanges saved to $configFile\n";
push @result, "Backup saved as $backupFile\n";

RETURN:

chomp @result;
chomp @errors;

# When run standalone, print to STDOUT
if ($caller) {
   return ( 
      join( "\n", @result ) . "\n",
      @errors ? join("\n", @errors) : ""
   );
} else {
   print "Results Summary:\n";
   print join( "\n", @result ) . "\n";
   if (@errors) {
      print "\n=== CLEANUP SCRIPT ERRORS ===\n";
      print join("\n", @errors) . "\n";
   }
   exit(@errors > 0 ? 1 : 0);
}
# End of script