#!/usr/bin/perl

#

# Convert EnergyPlus EPW weather file to DaySim wea format or CSV

#

# Axel Jacobs, 15 Dec 2013

use strict;

use warnings;

my $output;           # Default output is to STDOUT

my $csv = 0;          # Output CSV file, not DaySim wea format

my $delimiter = ' ';  # Delimiter. Default is ' ' which is for DaySim wea

my $delim = ' ';

while (@ARGV) {

	$_ = $ARGV[0];

	if (m/-o/) {         # Output file. Default is STDOUT

		$output = $ARGV[1];

		shift @ARGV;

	} elsif (m/-c/) {    # Output CSV file, not DaySim wea format

		$csv = 1;

	} elsif (m/-d/) {    # Delimiter for CSV output

		$delim = $ARGV[1];

		shift @ARGV;

	} elsif (m/^-\w/) {

		die("epw2wea: Bad option: $_\n");

	} else {

		last;

	}

	shift @ARGV;

}

if ($csv == 1) {

	$delimiter = $delim;     # Delimiter for CSV output

}

if ($output) {

   open(OUTPUT, '>', $output)

			or die("Cannot open file '$output' for writing: $!\n");

} else {

   *OUTPUT = *STDOUT;

}

# Extract latitude, longitude etc from first input line

my $line = <>;

#$line =~ s/\r//;    # Remove DOS line ending

chomp $line;

my @fields = split(/,/, $line);

my $city = $fields[1];

my $country = $fields[3];

my $lat = $fields[6];

my $lon = -1 * $fields[7];

my $mer = -15 * $fields[8];

my $ele = $fields[9];

if ($csv == 1) {

	my @epw_header = ('Year', 'Month', 'Day', 'Hour', 'Minute',

			'Uncertainty', 'DryBulb', 'DewPoint', 'RelHum', 'Press',

			'Ees0', 'Eesn0', 'Eird', 'Eeg', 'Eesn', 'Eed',

			'Evg', 'Evsn', 'Evd', 'Lz',

			'WindDir', 'WindSpeed',

			'TotalSkyCover', 'OpaqueSkyCover', 'Visibility', 'Ceiling',

			'PresentObs', 'PresentCode',

			'PrecWater', 'AerosolOpticalDepth', 'SnowDepth', 'LastSnowfall'

	);

	print OUTPUT join($delimiter, @epw_header) . "\n";

} else {

	print OUTPUT <<EndOfHeader;

place ${city}_$country

latitude $lat

longitude $lon

time_zone $mer

site_elevation $ele

weather_data_file_units 1

EndOfHeader

}

# Get rid of remaining header rows

for (my $i = 7; $i >= 1; $i--) {

	$line = <>;

}

# Process body

while (<>) {

	my $line = $_;

	$line =~ s/\r//g;    # Remove DOS line ending

	chomp $line;

	@fields = split(/,/, $line);

	my $month = $fields[1];

	my $day   = $fields[2];

	my $hour  = $fields[3];

	my $hour2 = sprintf '%.3f', $hour - .5;

	# Ignore minute column.

	my $Eeg   = $fields[13];

	my $Eesn  = $fields[14];

	my $Eed   = $fields[15];

	my $Evg   = $fields[16];

	my $Evsn  = $fields[17];

	my $Evd   = $fields[18];

	my @columns = ();

	if ($csv == 1) {

		# Output all columns if CSV output is requested

		@columns = @fields;

	} else {

		# Only output the columns relevant to DaySim wea format

		@columns = (

			$month,

			$day,

			$hour2,

			$Eesn,

			$Eed

		);

	}

	print OUTPUT join($delimiter, @columns) . "\n";

}

close(OUTPUT);

#EOF