my $prev_dst = "";
my $curr_dst = "";
my $dst_code = "";
my $dst_flag = "N";
my $dst_counter = 1;

foreach (@extended_records) {

	my @ext_lines = split /\n/, $_;
	foreach my $line_ext (@ext_lines) {

		my @ext_fields = split ",", $line_ext;

		# Get the fields from the Extended File.

		my $obs_day 		= $ext_fields[0];
		my $obs_month 		= $ext_fields[1];
		my $obs_year 		= $ext_fields[2];
		my $obs_hour 		= $ext_fields[3];
		my $obs_minute		= $ext_fields[4];
		my $obs_seconds 		= 0;

		my $temp_c		= $ext_fields[5];
		my $humidity_rh		= $ext_fields[6];
		my $dewpoint_c		= $ext_fields[7];
		my $wind_dir_degrees	= $ext_fields[12];
		my $wind_speed_mph	= $ext_fields[10];
		my $wind_gust_mph	= $ext_fields[11];
		my $pressure_hpa		= $ext_fields[9];
		my $rain_last_minute	= 0;
		my $rain_today		= $ext_fields[13];
		my $heat_index		= $ext_fields[8];
		my $rain_rate		= $ext_fields[14];
		my $soil_temp		= $ext_fields[15];
		my $weather_conditions	= $ext_fields[16];
		my $heat_word		= $ext_fields[17];
		my $ground_temp		= $ext_fields[18];
		my $solar			= $ext_fields[19];
		my $uv_index		= $ext_fields[20];
		my $solar_percentage	= $ext_fields[21];
		my $solar_description	= $ext_fields[22];
		my $et			= $ext_fields[23];
		my $burntime		= $ext_fields[26];
		my $sunshine		= $ext_fields[27];
		my $soil_moisture		= $ext_fields[28];
		my $leaf_wetness		= $ext_fields[29];
		my $cloud_height_metres	= $ext_fields[32];
		my $indoor_temp_c		= $ext_fields[35];
		my $indoor_humidity_rh	= $ext_fields[36];
		my $apparent_temp		= $ext_fields[37];
		my $apparent_solar_temp	= $ext_fields[38];
		my $humidex		= $ext_fields[40];
		my $air_density		= $ext_fields[44];

		# Format the collected data

		$temp_c =~ s/°C//;
		$dewpoint_c =~ s/°C//;
		$wind_dir_degrees =~ s/ °//;
		$wind_speed_mph =~ s/ mph//;
		$wind_gust_mph =~ s/ mph//;
		$pressure_hpa =~ s/ mb//;
		$rain_today =~ s/ mm//;
		$heat_index =~ s/°C//;
		$soil_temp =~ s/°C//;
		$solar_percentage =~ s/ %//;
		$humidex =~ s/°C//;

		# Get the Observation Date Time and keep in Local Format.

		my $obs_datetime_local = DateTime->new (
			year		=> $obs_year,
			month		=> $obs_month,
			day		=> $obs_day,
			hour		=> $obs_hour,
			minute		=> $obs_minute,	
			time_zone	=> 'Europe/London',
			);

		# Get the Observation Date Time and Convert to UTC.

		my $obs_datetime_utc = DateTime->new (
			year		=> $obs_year,
			month		=> $obs_month,
			day		=> $obs_day,
			hour		=> $obs_hour,
			minute		=> $obs_minute,	
			time_zone	=> 'Europe/London',
			);

		$obs_datetime_utc->set_time_zone( 'UTC' );

		my $dst = $obs_datetime_local->is_dst();

		# Combine the Current and Previous IsDST values to determine if the DST to GMT/UTC change has occured.

		$curr_dst = $dst;
		$dst_code = $prev_dst . $curr_dst;	

		# If the Previous DST is set (1) and the Current DST is not set (0) then set the DST Flag.

		if ($dst_code eq "10") {
			$dst_flag = "Y";
		}

		# If the DST Flag has been set then a change from DST to GMT/UTC has occurred.

		if ($dst_flag eq "Y") {

			# Subtract 1 from the Observation Hour to get the correct UTC Date/Time - construct the formated UTC Date & Time.

			my $dst_hour = $obs_hour - 1;
		
			my $dst_datetime_utc = DateTime->new (
				year		=> $obs_year,
				month		=> $obs_month,
				day		=> $obs_day,
				hour		=> $dst_hour,
				minute		=> $obs_minute,
				);

			$obs_datetime_utc = $dst_datetime_utc;

			# Reset the DST Flag and Counter after the hour requiring the change to UTC has been processed. 

			if ($dst_counter == 59) {
				$dst_flag = "N";
				$dst_counter = 1;
			}

			$dst_counter = $dst_counter + 1;

		}

		# Use the UTC Date/Time for the unformatted Observation Date & Time.

		my $rep_year = substr $obs_datetime_utc,0,4;
		my $rep_month = substr $obs_datetime_utc,5,2;
		my $rep_day = substr $obs_datetime_utc,8,2;
		my $rep_hour = substr $obs_datetime_utc,11,2;
		my $rep_minute = substr $obs_datetime_utc,14,2;
		my $rep_second = substr $obs_datetime_utc,17,2;

		# Output Record Line to a CSV File

		my $record_line = $rep_year . $rep_month . $rep_day . $rep_hour . $rep_minute . $rep_second . "," . $obs_datetime_utc . "," . $obs_datetime_local . "," . $temp_c . "," . $dewpoint_c . ",". $humidity_rh . "," . $wind_dir_degrees . "," . $wind_speed_mph . "," . $wind_gust_mph . "," . $pressure_hpa . "," . $rain_last_minute . "," . $rain_today . "," . $heat_index . "," . $rain_rate . "," . $soil_temp . "," . $weather_conditions . "," . $heat_word . "," . $ground_temp . "," . $solar . "," . $uv_index . "," . $solar_percentage . "," . $solar_description . "," . $et . "," . $burntime . "," . $sunshine . "," . $soil_moisture . "," . $leaf_wetness . "," . $cloud_height_metres . "," . $indoor_temp_c . "," . $indoor_humidity_rh . "," . $apparent_temp . "," . $apparent_solar_temp . "," . $humidex . "," . $air_density . "\n";

		print $record_line;

		my $file = "C:\\WEATHER_DATA_COLLECTOR\\BATHGATE\\" . $rep_year . $rep_month . "_BATHGATE.CSV";

		open (TXT, ">>", $file);
		print TXT $record_line;
		close (TXT);
	
		$prev_dst = $curr_dst;

	}	

}