#!/usr/bin/perl
# ipp: a preprocessor script
# author : Reese Jones rjones@sandia.gov (based on dprepro [Sandia])
# to do :
# priority (overide file defaults e.g. a=1 pfile a=2 -> a=2)
#     also order precedence: a=10 -p p.file b=12
# nested if/else/endif blocks

# Regular expressions for numeric fields
$e  = "-?(?:\\d+\\.?\\d*|\\.\\d+)[eEdD](?:\\+|-)?\\d+"; # exponential notation
$f  = "-?\\d+\\.\\d*|-?\\.\\d+";                        # floating point
$i  = "-?\\d+";                                         # integer
$ui = "\\d+";                                           # unsigned integer
$n  = "$e|$f|$i";                                       # numeric field

# Read command line arguments
while (scalar(@ARGV)) {
  $arg = shift(@ARGV);
  if    ($arg =~ /-p/) { $parameter_file = shift(@ARGV);
    parse_parameter_file($parameter_file);
  }
  elsif ($arg =~ /-o/) { $new_file = shift(@ARGV); }
  elsif ($arg =~ /=/)  { ($tag,$value) = split(/=/,$arg);
    $values_p1{$tag}  = $value;
  }
  else                 { $template_file = $arg; }
}

# Check for correct command line arguments
if( ! defined($template_file) ) {
  print STDERR "Usage: ipp <-p parameters_file> <name=value> template_file <-o new_file>\n";
  print STDERR "  note: \"value\" must be numeric (not a character string)\n";
  print STDERR "  parameter file format :  name = value\n";
  print STDERR "                    or  :  value name\n";
  print STDERR "  template  file example:  modulus is {10.0*name +3.2}\n";
  exit(-1);
}


# output
$output_fh = \*STDOUT;
if( defined($new_file) ) {
  open(NEW,">$new_file");
  $output_fh = \*NEW;
}
output($template_file,$output_fh);
if( defined($new_file) ) { close(NEW); }

# debug : print key--> value
#foreach $key (sort keys %values_p1) {
#  print "# $key ---> ",$values_p1{$key},"\n";
#}


###########################################################################
# parse parameter file
###########################################################################
# Read parameters file, extract tags and corresponding values in either aprepro
# "{ tag = value }" format or standard "value tag" format, and store the
# tag/value pairs in %values_p1.  
#  NOTE : compound expressions are not  currently allowed.

sub parse_parameter_file {
my $pfile = shift(@_);
# (1) parse numerical values
open (PARAMETERS, "<$pfile") || die "Can't open parameters file: $pfile: $!";
while (<PARAMETERS>) { # read each line of file, one at a time
  # extract tag/value fields allowing multiple matches per line in either format
  foreach $field (m/(?:$n)\s+\w+|\s*\w+\s*=\s*(?:$n)\s*/go) {
    # extract tag/value pair from each field NOTE () are memory
    if ( ( ($value, $tag) = ($field =~ m/^($n)\s+(\w+)$/o) ) ||       # Standard
         ( ($tag, $value) = ($field =~ m/^\s*(\w+)\s*=\s*($n)\s*$/o))){# Apr
      $value =~ s/[dD]/e/o;      # convert any F77 dbl prec exponents
      $values_p1{$tag} = $value; # store in hash
    }
  }
}
close (PARAMETERS);

# (2) parse string values in dbl quotes
open (PARAMETERS, "<$pfile") || die "Can't open parameters file: $pfile: $!";
while (<PARAMETERS>) { # read each line of file, one at a time
  # extract tag/value fields allowing multiple matches per line in either format
  #if ( m/=/ && m/\"/ ){
  if ( ($tag, $value) = ($_ =~ m/^\s*(\w+)\s*=\s*\"(.*)\"\s*$/o)){
    $values_p1{$tag} = $value; # store in hash
  }
}
close (PARAMETERS);
}

#################################################################
# Process template simulation file and create new simulation file
#################################################################
# Read each line of template_file, find the {} fields, process any
# assignments or expressions, and substitute the corresponding values.
# Print each line with substitution to new_file.  The parameters
# file assignments (%values_p1 = precedence 1) take precedence over any
# duplicate template file assignments (%values_p2 = precedence 2) in
# order to allow the flexibility to define defaults in the template
# file which can then be overridden by a particular parameters file.

sub output{
my $tfile = shift (@_);
# Open the template simulation file for input.
open (TEMPLATE, "<$tfile") || die "Can't open template file $tfile: $!";
# Open the new simulation file for output.
#$print_to_file = 0;
#if (defined($new_file)) {
#open (NEW, ">$new_file") || die "Can't create instance file $new_file: $!";
#$print_to_file = 1;
#}
$print_to_file = 1;
$fh = shift (@_);

$print = 1; # print line flag
while (<TEMPLATE>) {

  # Extract each {} match from this line
  foreach $field (m/\{\s*(.+?)\s*\}/go) { # ".+?" provides a minimal match

    # Case 1: test for simple tag match "{tag}"
    if ($field =~ m/^\w+$/o) {
      if ( defined ( $value = $values_p1{$field} ) ||
           defined ( $value = $values_p2{$field} ) ) { # or exists $values{$tag}
        s/\{\s*$field\s*\}/$value/;
      }
    }

    # Case 2: test for assignment "{tag = field}"
    elsif ( ($tag, $assign) = ($field =~ m/^(\w+)\s*=\s*(.+?)$/o) ) {

      # Case 2a: assignment of numerical value
      # ($n = exponential notation $e, floating point $f, or integer $i)
      if ($assign =~ m/^($n)$/o) {
        $assign =~ s/[dD]/e/o;               # convert F77 dbl prec exponents
        $values_p2{$tag} = $assign;          # store in priority 2 hash
        s/\{\s*$tag\s*=\s*.+?\s*\}/$assign/; # replace assignment with value
      }

      # Case 2b: assignment of expression.  Evaluate $assign by replacing any
      # known tags with their values and then eval the remaining expression.
      else {
        foreach $exptag ($assign =~ m/\b(\w*[a-zA-Z_]+\w*)\b/go) {
          if ( defined ( $value = $values_p1{$exptag} ) ||
               defined ( $value = $values_p2{$exptag} ) ) {
            $assign =~ s/$exptag/$value/;
          }
        }
        $value = eval $assign;
        if ($@) { die "Eval error: $@"; }
        $values_p2{$tag} = $value;          # store in priority 2 hash
        s/\{\s*$tag\s*=\s*.+?\s*\}/$value/; # replace assignment with value
      }
    }

    # Case 3: assume general expression in all remaining $field matches.
    # Evaluate $field by replacing any known tags with their values and
    # then eval the remaining expression.
    else {
      foreach $tag ($field =~ m/\b(\w*[a-zA-Z_]+\w*)\b/go) {
        if ( defined ( $value = $values_p1{$tag} ) ||
             defined ( $value = $values_p2{$tag} ) ) {
          $field =~ s/$tag/$value/;
        }
      }
      s/\{\s*.+?\s*\}/eval $field/e;
      if ($@) { die "Eval error: $@"; }
    }
  }

  # if/else blocks
  if ($_ =~ /#if/) {
    $line = $_; chomp($line); $line =~ s/^\s+//; $line =~ s/\s+$//;
    @items = split(/\s+/,$line);
    if (eval($items[1])) {;}
    else { $print = 0;}
  }
  elsif ($_ =~ /#else/) {
    if ($print) {$print = 0;} else {$print = 1;}
  }
  elsif ($_ =~ /#endif/) {
    $print = 1;
  }
  else { 
    # output the processed line 
    if ($print) { print $fh $_; }
  }

}
close (TEMPLATE);
if ($print_to_file ) { close (NEW); }
}

###########################################################################
# math operators
###########################################################################

# Intrinsic numeric operators include +,-,*,/,**,%,<<,>>,sqrt(),abs(),
# sin(),cos(),atan2(),exp(),log(),int(),hex(),oct(),rand(),srand().

# Augment these with others (adapted/extended from bprepro by Bob Walton).
# NOTE: convert from degs to rads by pi/180 = (pi/4)/45 = atan2(1,1)/45
#       convert from rads to degs by 180/pi = 45/atan2(1,1)

# additional logarithmic functions

sub log10 { log($_[0])/log(10) }

# additional trigonometric functions with radian input

sub tan { sin($_[0])/cos($_[0]) }

sub cot { cos($_[0])/sin($_[0]) }

sub csc { 1/sin($_[0]) }

sub sec { 1/cos($_[0]) }

# trigonometric functions with degree input

sub sind { sin($_[0]*atan2(1,1)/45) }

sub cosd { cos($_[0]*atan2(1,1)/45) }

sub tand { tan($_[0]*atan2(1,1)/45) }

sub cotd { cot($_[0]*atan2(1,1)/45) }

sub cscd { 1/sin($_[0]*atan2(1,1)/45) }

sub secd { 1/cos($_[0]*atan2(1,1)/45) }

# inverse trigonometric functions returning radians

sub asin {
  if (abs($_[0]) > 1) { die "input out of range in asin()\n"; }
  atan2($_[0],sqrt(1-$_[0]**2));
}

sub acos {
  if (abs($_[0]) > 1) { die "input out of range in acos()\n"; }
  atan2(sqrt(1-$_[0]**2),$_[0]);
}

sub atan { atan2($_[0],1) }

# inverse trigonometric functions returning degrees

sub asind { asin($_[0])*45/atan2(1,1) }

sub acosd { acos($_[0])*45/atan2(1,1) }

sub atand { atan2($_[0],1)*45/atan2(1,1) }

sub atan2d { atan2($_[0],$_[1])*45/atan2(1,1) }

# hyperbolic functions

sub sinh { (exp($_[0]) - exp(-$_[0]))/2 }

sub cosh { (exp($_[0]) + exp(-$_[0]))/2 }

sub tanh { sinh($_[0])/cosh($_[0]) }

sub coth {
  if ($_[0] == 0) { die "input out of range in coth()\n"; }
  cosh($_[0])/sinh($_[0]);
}

sub csch {
  if ($_[0] == 0) { die "input out of range in csch()\n"; }
  1/sinh($_[0]);
}

sub sech { 1/cosh($_[0]) }

# inverse hyperbolic functions

sub asinh { log($_[0] + sqrt($_[0]**2 + 1)) }

sub acosh {
  if ($_[0] < 1) { die "input out of range in acosh()\n"; }
  log($_[0] + sqrt($_[0]**2 - 1));
}

sub atanh {
  if (abs($_[0]) >= 1) { die "input out of range in atanh()\n"; }
  log((1+$_[0])/(1-$_[0]))/2;
}