#!/usr/local/bin/perl

# perl script for Circular Tower Rafter Calculations

use CGI::Carp qw(fatalsToBrowser); #comment out this line when your done debugging this script

$|++;	#dont't buffer output

#use strict;

# file name:: circular-tower.cgi
#	Created on Sunday, July 15, 2007 by	Sim Ayers of SBE Builders
#   get latest version of this script at http://www.sbebuilders.com 
###################################################
#   You are free to customize this script as you wish.
#	DISCLAIMER
#	The information and code provided is provided 'as is' without 
#	warranty of any kind, either express or implied. In no event 
#	shall the Company SBE Builders be liable for any damages whatsoever 
#	including direct, indirect, incidental, consequential, loss of 
#	business profits or special damages, even if the author has been 
#	advised  of the possibility of such damages.
#	DO NOT USE THIS SCRIPT UNLESS YOU CAN FULLY AGREE WITH THIS 
#	DISCLAIMER.
#   copyright(C) 2007
###################################################
=head
In a circle of radius r, the length of the chord that 
subtends a central angle x is r * sin( x/2). 

This script uses the theory of an polygon inscribed inside of a circle.
So the radius is the run of the polygon hips and
the chord is the length of the sides of the polygon.

=cut


my ($content_type_printed,%data,$back_wall,$projection,$face_wall,$pitch,$show_feet_inches);
# print out perl headers to browser
print "Content-type: text/plain\n\n" unless $content_type_printed++;

&read_input();		#read user input variables

$plate_width = 5.5;
$fascia_width = 1.5;
$ply_cut_off = 16;

if ($data{'radius'} eq ""){
# hand edit variables below for default values
$radius = 96;
$pitch = 8;
$show_feet_inches = 'no';
$spacing = 8;
$overhang = 24;
}
else{
$radius = $data{'radius'};
$pitch = $data{'pitch'};
$show_feet_inches = $data{'show_feet_inches'};
$spacing = $data{'spacing'};
$overhang = $data{'overhang'};
}


#Global symbols
# http://perldoc.perl.org/Math/Complex.html
use Math::Complex qw(:trig);
use POSIX qw(ceil floor);

$PIE  = 3.14159265358979323846;
$RAD_TO_DEGREE  = (180/pi);
$DEGREE_TO_RAD  = ($PIE/180);
$RAD_TO_DEGREE45  = (0.785398163397448309616);
$dxf_line_count = 100;
$dxf_circle_count = 200;
$arc_count = 300;
$DXF_STYLE=0;      	#dxf Line style
$DXF_LAYER=0;     	#dxf file LAYER number
$DXF_COLOR=0;    	# dxf line color
$DXF_TSIZE=4.0;  	#dxf default dxf text size
$half_the_thickness_of_the_hips = 0.75;

# get geometry angles for circle
$run = $radius;

$circumference = 2 * $PIE * $radius;
$circumference_fascia_line = 2 * $PIE * ($radius + $overhang);
$nsides = ceil($circumference / $spacing);
$angle_deg = 360 / ($nsides *2);

$common_count = $nsides;

$cord = 2 * $radius *  sin(($angle_deg) * $DEGREE_TO_RAD);
$cord_inside = 2 * ($radius - $plate_width) *  sin(($angle_deg) * $DEGREE_TO_RAD);
$cord_at_overhang = 2 * ($radius + $overhang - $fascia_width) *  sin(($angle_deg) * $DEGREE_TO_RAD);
$area = ($circumference * $radius) / 2;

$arc_segment = $radius *  ($angle_deg * $DEGREE_TO_RAD);

$pitch_angle = $RAD_TO_DEGREE * atan($pitch / 12);
$Major_Pitch = atan($pitch / 12);

$common_rafter_rise = $run * ($pitch / 12);
$common_rafter_length = $run / cos(atan($pitch / 12));
$overhang_length = $overhang / cos(atan($pitch / 12));

$plywood_count = 0;
$num_rows = ceil((($radius + $overhang) / cos(atan($pitch / 12)))/48);

for($i=0; $i<$num_rows; $i++){

    $circumference_row = 2 * $PIE * (($radius + $overhang - ((48 * $i) * cos(atan($pitch / 12)))));
    $count =  ceil($circumference_row / (96 - $ply_cut_off));
    $plywood_count += $count;
    #print "\n\n ply $i $count = " .convertTOfeet($circumference_row);
    #print "\n\n";
} 



print "Circular Tower Rafter Calculations";
print "\nCalculations are rounded to the nearest 1/16 inch";

print "\n\n Radius of Tower = " .convertTOfeet($radius);
print "\n\n Circumference of Tower Plate Line= " .convertTOfeet($circumference);
print "\n\n Circumference At Fascia Line = " .convertTOfeet($circumference_fascia_line);

print "\n\n\n Common Rafter Run = " .convertTOfeet($run);
print "\n\n Common Rafter Pitch = " .roundAngle($pitch);
print "\n\n Common Rafter Pitch Angle = " .roundAngle($pitch_angle);
print "\n\n Common Rafter Rise = " .convertTOfeet($common_rafter_rise);
print "\n\n Common Rafter Length = " .convertTOfeet($common_rafter_length);
print "\n\n Common Rafter Overhang Run = " .convertTOfeet($overhang);
print "\n\n Common Overhang Rafter Length = " .convertTOfeet($overhang_length);
print "\n\n Common Rafter Length To Fascia Line= " .convertTOfeet($common_rafter_length + $overhang_length);
print "\n\n Common Rafter Spacing = " .convertTOfeet($spacing);
print "\n\n Number of Common Rafters at $spacing'' O.C = " .$common_count;
print "\n\n Common Rafter spacing at plate = " .convertTOfeet($cord);
print "\n\n Common Rafter spacing at inside of plate = " .convertTOfeet($cord_inside);
print "\n\n Common Rafter spacing at inside of fascia = " .convertTOfeet($cord_at_overhang);
print "\n\n Plywood Roof Sheathing Count = " .$plywood_count;

# text file with dxf header information
$DXF_HEADER_FILE = "dxf_header.txt";
# text file to save dxf drawing to
$DXF_File="circular-tower.dxf";

#load dxf header file
$dxf_header = get_dxf_header_file($DXF_HEADER_FILE);

open(FILE, ">$DXF_File") ||  die("$DXF_File:  Can't  open because ($!).");

# add dxf header information to dxf output file
print FILE  "$dxf_header\n0\n";

# origin center in dxf document
$originX = 100;
$originY = 100;

$theta = (2 * $PIE) / $nsides;
$start_angle = $theta / 2;

$x1 = $originX; 
$y1 = $originY; 

$radius2 = $overhang + $radius;
$radius3 = $overhang + $radius - $fascia_width;

	 
# draw outside circumference circular plate
dxf_circle($originX,$originY,$radius);
# draw insidee circumference circular plate
dxf_circle($originX,$originY,$radius - $plate_width);
# draw outside circumference circular fascia line
dxf_circle($originX,$originY,$radius2);
# draw inside circumference circular fascia line
dxf_circle($originX,$originY,$radius3);


# draw common rafters
 for($i=1; $i<=$nsides; $i++){          
	 
	 $x2 = $radius3 * cos(($theta * $i) + $start_angle);
	 $y2 = $radius3 * sin(($theta * $i) + $start_angle);
	 $x2 += $originX;
	 $y2 += $originY;	 
     dxf_line($x1,$y1,$x2,$y2);   
          
}



$str= "ENDSEC\n0\nEOF";

print FILE  $str;
close FILE;


exit;


###################################
# library sub routines follow
###################################
# [Ctrl]+E for zoom extents 

sub dxf_line
{
my ($x1,$y1,$x2,$y2) = @_;

    $color=0;
	$dxf_line_count++;
	
	
	$str = sprintf("LINE\n5\n%dD\n8\n%d\n6\nCONTINOUS\n62\n%d\n10\n%lf\n20\n%lf\n30\n0.0\n11\n%lf\n21\n%lf\n31\n0.0\n0\n",
	$dxf_line_count,$DXF_LAYER,$DFX_COLOR,$x1,$y1,$x2,$y2);

    #print $str;
	print FILE  $str;
}
#=============================================================================#
sub dxf_arc
{
my ($x1,$y1,$radius) = @_;

 $start=0.0000;
 $end=180.0000;
 $arc_count++;
 
	$str = sprintf("0\nARC\n5\n26\n8\n0\n62\n%d\n10\n%lf\n20\n%lf\n30\n0\n40\n%lf\n50\n%lf\n51\n%lf\n",
	$DFX_COLOR,$x1,$y1,$radius,$start,$end);
	
	$str = sprintf("ARC\n5\n8B\n8\n0\n62\n%d\n10\n%lf\n20\n%lf\n30\n0.0\n40\n%lf\n50\n%lf\n51\n%lf\n0\n",
	$DFX_COLOR,$x1,$y1,$radius,$start,$end);
	
	$str = sprintf("ARC\n8\n0\n62\n%d\n10\n%lf\n20\n%lf\n30\n0.0\n40\n%lf\n50\n%lf\n51\n%lf\n0\n",
	$DFX_COLOR,$x1,$y1,$radius,$start,$end);
	
	$str = sprintf("ARC\n5\n%dA\n8\n0\n62\n%d\n10\n%lf\n20\n%lf\n30\n0.0\n40\n%lf\n50\n%lf\n51\n%lf\n0\n",
	$arc_count,$DFX_COLOR,$x1,$y1,$radius,$start,$end);
	
    
	print FILE  $str;
}

#=============================================================================#
sub dxf_circle{
	my ($x1,$y1,$radius) = @_;
    $dxf_circle_count++;
	$str = sprintf("CIRCLE\n5\n10B%d\n8\n0\n10\n%lf\n20\n%lf\n30\n0\n40\n%lf\n0\n",
	$dxf_circle_count,$x1,$y1,$radius);
	
    print FILE  $str;
	
}
#=============================================================================#
sub escape_string {
    my($esc) = @_;
    $esc =~ s/([^a-zA-Z0-9_\-.])/uc sprintf("%%%02x",ord($1))/eg;
	$esc =~ s/ /+/g;
    return $esc;
}

#=============================================================================#
sub get_dxf_header_file{
    my($file)=shift;
    my $header;
    open(FH, "<$file") ||  die("$file:  Can't  open because ($!).");
	while(<FH>){
	   $header .= $_;
	}
	close(FH);
	return $header;
}	
#=============================================================================#
sub hypot{
my ($x,$y) = @_;
my $s = sqrt( $x* $x + $y * $y);
return $s;
}
#=============================================================================#
sub convertTOfeet{
my ($decimal) = @_;
    return $decimal unless $show_feet_inches eq 'yes';
    
    #print "\n inches decimal = " .$decimal;
    
   my $wholefeet = floor($decimal/12);
   my $wholeinch = floor($decimal - ($wholefeet*12));
   my $decimalfrac = ($decimal*1) - floor($decimal);
   my ($frac1,$frac2,$frac_str);
   $frac2 = 16;
   if ($decimalfrac >= 0.9774) # 15/16 = 0.9375
   {
      $wholeinch++;
      $decimalfrac = 0.00;
      if($wholeinch == 12)
      {
         $wholefeet++;
         $wholeinch = 0;
      }
   }
   
   if ($decimalfrac > 0.0001)
   {      
        $frac1 = $decimalfrac * $frac2;
        my $wholefrac = floor($decimalfrac * $frac2);
        $frac1 = ceil($decimalfrac * $frac2);
        $frac1 = 15 if($frac1 == 16);
        ($frac1,$frac2) = check_frac($frac1,$frac2);
        $frac_str =	sprintf(" %d/%d",$frac1,$frac2);
	}
	
   my $str =	sprintf("%d'-%d%s''",
	$wholefeet,$wholeinch,$frac_str);
	

   return $str;
}

#=============================================================================#
sub check_frac{
my ($numerator ,$denominator) = @_;
          
    return (7,8) if $numerator  eq 14;
    return (3,4) if $numerator  eq 12;
    return (5,8) if $numerator  eq 10;
    return (1,2) if $numerator  eq 8;
    return (3,8) if $numerator  eq 6;
    return (1,4) if $numerator  eq 4;
    return (1,8) if $numerator  eq 2;	
    return ("","") if $numerator  eq 0;	
    return ("","") if $denominator  eq 0;	

   return ($numerator ,$denominator);
}

#=============================================================================#
sub roundAngle{
my ($angle) = @_;
 my $str =	sprintf("%.2f",$angle);
 return $str;
 
}
#===================================================================#
sub read_input {

	my($buffer) = undef;
	my ($item);
	if ($ENV{'REQUEST_METHOD'} eq 'POST') {	
		read(STDIN,$buffer,$ENV{'CONTENT_LENGTH'});
	}
	else {
		$buffer=$ENV{'QUERY_STRING'};
	}

	$buffer = $ARGV[0]  if (not $buffer);

	my @pairs=split(/&/,$buffer);
	foreach $item(@pairs) {
		my ($key,$content)=split (/=/,$item,2);    # Split into key and value.
		$content =~ tr/+/ /; # Convert plus's to spaces
		$content =~ s/%(..)/pack("c",hex($1))/ge;	# Convert %XX from hex numbers to alphanumeric
		$content =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C", hex($1))/eg;
		# prevent hackers from exploiting the input name
		$key =~ tr/+/ /; # Convert plus's to spaces
		$key =~ s/%(..)/pack("c",hex($1))/ge;	# Convert %XX from hex numbers to alphanumeric
		$key =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C", hex($1))/eg;	
        $key =~ s/ /_/g;
   
		# get rid of attempts to insert HTML tags
		$content =~ s/<!--(.|\n)*-->//g;  # server-side-includes
		$content =~ s/<([^>]|\n)*>//gs;
		$content =~ s/</&lt;/g; 
		$content =~ s/>/&gt;/g;

	
		# get rid of attempts to insert illegal characters
		$content =~ s/\\//g; # remove black slashes
		$content =~ s/\0//g; # remove nulls
		$content =~ s/[\\\&\;\`\'\"\|\*\?\~\^\[\]\{\}\$]//gs;
		$content =~ s/\cM/\n/g;	#convert CR to LF
		$content =~ s/^\s+|\s+$//gs;
		$content = substr($content,0,4096);
		$data{$key} = $content;
		
	}
	return 1;
}