#!/usr/bin/env perl

# zpoolStats - Display ZFS pool status and capacity statistics
#
# PURPOSE:
#   Reports comprehensive status information for all ZFS pools on the system,
#   including capacity, fragmentation, and health status. Essential for monitoring
#   pool health during sneakernet operations.
#
# USAGE:
#   Standalone: ./zpoolStats
#   From sneakernet: Executed automatically during cleanup phase
#   From Perl script: my ($results, $errors) = eval { do './zpoolStats' };
#
# EXECUTION CONTEXT:
#   When executed by sneakernet on the target server:
#   - Script is read from transport drive, decrypted, and executed via eval()
#   - Results returned as tuple (output, error_messages) for logging
#   - When run standalone, prints results to STDOUT
#
# BEHAVIOR:
#   1. Executes 'zpool list' with comprehensive output columns
#   2. Shows: pool name, size, allocated space, free space, fragmentation, capacity, health
#   3. Returns formatted output with any error messages
#
# OUTPUT FORMAT:
#   NAME     SIZE  ALLOC   FREE    FRAG    CAP  HEALTH
#   backup   10T   4.5T   5.5T     12%    45%  ONLINE
#   storage  20T   15T    5T       8%     75%  ONLINE
#
# RETURN VALUE:
#   When called from another script: ($results, $errors)
#   - $results: String containing zpool list output
#   - $errors: String containing error messages (empty if none)

use strict;
use warnings;

# Get zpool list output
my $zpool_cmd = 'zpool list -o name,size,alloc,free,frag,cap,health';
my @results = `$zpool_cmd 2>&1`;
chomp @results;
my @errors;

# Check if command executed successfully
if ($? != 0) {
   push @errors, "Error executing zpool list: $!";
}

# Return or print results depending on context
if (caller()) { # called from another script
   return ( 
      join( "\n", @results ) . "\n",
      @errors ? join("\n", @errors) : ""
   );
} else { # run standalone
   print "Results Summary:\n";
   print join( "\n", @results ) . "\n";
   if (@errors) {
      print "\n=== CLEANUP SCRIPT ERRORS ===\n";
      print join("\n", @errors) . "\n";
   }
}
# End of script