#!/usr/bin/env perl 

# cklg: a script to check SAS log files for errors, warnings, and other 
# messages that indicate potential problems. 
#
# cklg operates on the command line and can process multiple files.
# It can be customized for the log messages to find and for the
# log messages to ignore.  There are only 2 optional command line
# parameters, besides the file name(s) to check: give a usage message
# and list the strings that will be searched. cklg should be portable
# to any system with Perl and an available command line.
#
# cklg was intended to work with the Vim editors's quickfix facility. 
# Thus, it provides the log file name and the line number of the error 
# in addition to the error text. It also can be run as a stand alone
# program.
#
# Original version 01JUN2009 by Kent Nassen.
# Updated to use lexical filehandles and modern Perl practices.

use strict;
use warnings;
use Getopt::Std;
use vars qw($version $file $ProgName $query $filename @search $opt_h $opt_l $count $term $i $line $line_number);

$version = "v1.1, " . scalar(localtime);
($file, $ProgName, $query, $filename) = ("", "", "", "");
@search = ();
($opt_h, $opt_l) = ('', '');

($ProgName = $0) =~ s%.*/%%;  # Unix
#($ProgName = lc $0) =~ s%.*\\%%;  # DOS

# Initialize options

getopts('hl');

if ($opt_h or ($#ARGV < 0 and not $opt_l)) { DisplayUsage(); }

# The list of SAS log message strings to search for.  Add more here if
# needed.  A case-insensitive search will be used later.
@search = ( "error",
            "fatal",
            "warning:",
            "syntax error",
            "converted",
            "uninitialized",
            " 0 obs",
            "no obser",
            "repeats of",
            "not found",
            "could not be loaded",
            "w.d. format was too small",
            "not valid",
            "not executed",
            "invalid",
            "overwritten",
            "missing values were generated",
            "outside the axis range",
            "duplicate by var",
            "not created",
            "contained a missing",
            "already sorted",
            "already on the library",
            "ignored",
            "went to new line",
            "no effect",
            "division by zero",
            "stopped",
            "due to loop" 
          );

# List the search terms used by the program.
if ($opt_l) {
    # loop over elements in the array
    print "\nThe log search terms used by $ProgName are: \n";
    $count = 0;
    foreach $term (@search) {
        print "   $term\n";
        $count++;
    }
    print "\n$count terms defined.\n\n";
    exit 0;
}

# Build the query (if statement) from the array elements
for ($i = 0; $i < @search; $i++) {
    if ($i == 0) {
        $query = "if (m/" . $search[$i] . "/i\n";
    } else {
        $query .= "or m/" . $search[$i] . "/i\n";
    }
}
# Finish building the if statement.
$query=$query.")\n { print \"\$filename:\$.:\",\$_,\"\\n\"\; }";
# Loop through file names on the command line and process each.
foreach $file (@ARGV) {
    $filename = $file;  # Set the global filename for use in the query
    Process($file);
}

# Process looks for errors and warnings and prints the findings.
sub Process {
    my ($file_to_process) = @_;
    
    # We need to use $file_to_process within the function but use the global $filename 
    # in the query for consistent behavior with the original script
    
    # Use lexical filehandle (modern Perl practice)
    my $fh;
    open $fh, '<', $file_to_process or do {
        print STDERR "\n   *** $ProgName: Can't open '$file_to_process': $!\n\n";
        return;
    };
    
    $line_number = 0;
    while ($line = <$fh>) {
        $line_number = $.;  # Save current line number
        chomp($line);
        $line =~ s/\r.*$//; # Remove the overprinted text on the line
        
        # Log messages that look like errors but we don't want to report
        if (
            $line =~ m/Errors printed on/i 
            or $line =~ m/will be automatically converted/i
            # add more message to skip here
        ){ 
            next; 
        }
        
        # This does the log search by executing the if
        # statement contained in the variable $query created
        # earlier. Add more terms above.
        # We need to localize $_ for the eval to work properly
        local $_ = $line;
        local $. = $line_number;  # Ensure line number is consistent
        
        # Execute the dynamic search query
        eval $query;
        if ($@) {
            warn "Error evaluating query: $@";
        }
    } # end of input while loop 
    close $fh;
}   # end of sub process

# DisplayUsage gives a usage message.
sub DisplayUsage {
    print STDERR "\n  $ProgName: Search SAS logs for errors and warnings\n",
                "               by Kent Nassen, $version\n",
                "\n   Usage: $ProgName [filename...]\n",
                "         -h    Display this usage message\n",
                "         -l    List the search terms\n",
                "\n",
                "   Examples: $ProgName test.log  or  $ProgName *.log", 
                "  or  $ProgName -l\n\n";
    exit 0;
}