#!/usr/bin/perl

#
#    Grabs the latest local weather conditions from the National Weather Service (NWS).
#    Uses the decoded METAR reports.
#
#    Need to give the 4-character METAR station code on the Command Line. E.g.;
#
#           GrabWeather KLAM
#


    require "ctime.pl";


    #
    #  Change to users home directory. We used to dump into /tmp
    #  but using home dir instead avoids multiple users interfering
    #  with one another. (Yeah, we could "unique-ize" the filenames, but
    #  this is easier for now...)
    #
    $home = (getpwuid($<))[7];
    $ok = chdir() || chdir($home);


    #
    #  Check to see if .wmWeatherReports exists.
    #  If not, make it and move to it.
    #
    if ( !(-e ".wmWeatherReports") ){
	mkdir(".wmWeatherReports", 0775);
    }
    chdir(".wmWeatherReports");





    $StationID    = $ARGV[0];
    $HTMLFileName = "$StationID.TXT";
    $URL          = "ftp://weather.noaa.gov/data/observations/metar/decoded/$HTMLFileName";
    $DataFileName = "$StationID.dat";




    #
    #  I think some of these wget command line options may cause problems
    #  for some people? Dont know why... (Perhaps they have a ~/.wgetrc file
    #  that overrides command line options?).
    #
    $GrabCmd = "wget --proxy=off --passive-ftp --tries 0 -q -O $home/.wmWeatherReports/$StationID.TXT $URL";
    system "$GrabCmd";




    #
    # Parse HTML File.
    #
    $Temp     = -999.0;
    $Chill    = -999.0;
    $DewPnt   = -999.0;
    $Pressure = -999.0;
    $Hum      = -999.0;
    $Flag = 0;
    open(TmpFile, "$HTMLFileName");
    while (<TmpFile>){
        chop;
	if ($Flag == 0) { $StationInfo = $_; };
	if ($Flag == 1) { $UpdateTime = $_; };
	if ($_ =~ /^Sky conditions:/ ){ $SkyConditions = $_; $SkyConditions =~ s/Sky conditions: (.*)/\1/; }
	if ($_ =~ /^Temperature:/ ){ $Temp = $_; $Temp =~ s/Temperature:\s*(\-{0,1}[0-9.]{1,}).*/\1/; }
	if ($_ =~ /^Windchill:/ ){ $Chill = $_; $Chill =~ s/Windchill:\s*(\-{0,1}[0-9.]{1,}).*/\1/; }
	if ($_ =~ /^Dew Point:/ ){ $DewPnt = $_; $DewPnt =~ s/Dew Point:\s*(\-{0,1}[0-9.]{1,}).*/\1/; }
	if ($_ =~ /^Pressure \(.*\):/ ){ $Pressure = $_; $Pressure =~ s/Pressure \(.*\):\s*([0-9.]{2,}).*/\1/; }
	if ($_ =~ /^Relative Humidity:/ ){ $Hum = $_; $Hum =~ s/Relative Humidity:\s*(\d{1,})\%.*/\1/; }
	if ($_ =~ /^ob: / ){ $CodedMETAR = $_; $CodedMETAR =~ s/ob: (.*)/\1/; }
	++$Flag;
    }
    close(TmpFile);




    #
    #  Isolate the Wind groups out of the coded METAR report.
    #  There may be two groups - the normal one and a variability set.
    #
    $WindGroup = $CodedMETAR;
    $WindGroup =~ s/ RMK\s.*$//;
    $VarWindGroup = $WindGroup;


    if ($WindGroup =~ /.*\s\w{3}\d{2,3}KT\s\d{3}V\d{3}\s.*/ ) {
        $VarWindGroup =~ s/.*\s\w{3}\d{2,3}KT\s(\d{3}V\d{3})\s.*/\1/;
        $VarFlag = 1;
    } elsif ($WindGroup =~ /.*\s\w{3}\d{2,3}MPS\s\d{3}V\d{3}\s.*/ ) {
        $VarWindGroup =~ s/.*\s\w{3}\d{2,3}MPS\s(\d{3}V\d{3})\s.*/\1/;
        $VarFlag = 1;
    } elsif ($WindGroup =~ /.*\s\w{3}\d{2,3}G\d{2,3}KT\s(\d{2,3}V\d{2,3})\s.*/ ) {
        $VarWindGroup =~ s/.*\s\w{3}\d{2,3}G\d{2,3}KT\s(\d{2,3}V\d{2,3})\s.*/\1/;
        $VarFlag = 1;
    } elsif ($WindGroup =~ /.*\s\w{3}\d{2,3}G\d{2,3}MPS\s(\d{2,3}V\d{2,3})\s.*/ ) {
        $VarWindGroup =~ s/.*\s\w{3}\d{2,3}G\d{2,3}MPS\s(\d{2,3}V\d{2,3})\s.*/\1/;
        $VarFlag = 1;
    } else {
	$VarWindGroup = "";
        $VarFlag = 0;
    }
    $Direction1 = $VarWindGroup; $Direction1 =~ s/(\d{3})V\d{3}/\1/;
    $Direction2 = $VarWindGroup; $Direction2 =~ s/\d{3}V(\d{3})/\1/;



    $GustFlag = 0;
    if ($WindGroup =~ /.*\s\w{3}\d{2,3}KT\s.*/ ) {
        $WindGroup =~ s/.*\s(\w{3}\d{2,3}KT)\s.*/\1/;
	$Direction = $WindGroup; $Direction =~ s/(\w{3})\d{2,3}KT/\1/;
	$Speed = $WindGroup; $Speed =~ s/\w{3}(\d{2,3})KT/\1/;
    } elsif ($WindGroup =~ /.*\s\w{3}\d{2,3}MPS\s.*/ ) {
        $WindGroup =~ s/.*\s(\w{3}\d{2,3}MPS)\s.*/\1/;
	$Direction = $WindGroup; $Direction =~ s/(\w{3})\d{2,3}MPS/\1/;
	$Speed = $WindGroup; $Speed =~ s/\w{3}(\d{2,3})MPS/\1/;
	$Speed *= 1.942;
    } elsif ($WindGroup =~ /.*\s\w{3}\d{2,3}G\d{2,3}KT\s.*/ ) {
        $WindGroup =~ s/.*\s(\w{3}\d{2,3}G\d{2,3}KT)\s.*/\1/;
	$Direction = $WindGroup; $Direction =~ s/(\w{3})\d{2,3}G\d{2,3}KT/\1/;
	$Speed1 = $WindGroup; $Speed1 =~ s/\w{3}(\d{2,3})G\d{2,3}KT/\1/;
	$Speed2 = $WindGroup; $Speed2 =~ s/\w{3}\d{2,3}G(\d{2,3})KT/\1/;
	$GustFlag = 1;
    } elsif ($WindGroup =~ /.*\s\w{3}\d{2,3}G\d{2,3}MPS\s.*/ ) {
        $WindGroup =~ s/.*\s(\w{3}\d{2,3}G\d{2,3}MPS)\s.*/\1/;
	$Direction = $WindGroup; $Direction =~ s/(\w{3})\d{2,3}G\d{2,3}MPS/\1/;
	$Speed1 = $WindGroup; $Speed1 =~ s/\w{3}(\d{2,3})G\d{2,3}MPS/\1/;
	$Speed2 = $WindGroup; $Speed2 =~ s/\w{3}\d{2,3}G(\d{2,3})MPS/\1/;
	$Speed1 *= 1.942; $Speed2 *= 1.942;
	$GustFlag = 1;
    } else {
        $WindGroup = "";
    }



    #
    #  Get the Time out of the coded Metar Report.
    #
    $UniversalTime = $CodedMETAR;
    if ($UniversalTime =~ /$StationID \d{1,2}\d{2}\d{2}Z/ ){

        $UniversalTime =~ s/$StationID (\d{1,2})(\d{2})(\d{2})Z .*/\2:\3/;

    } else {

        $UniversalTime = "99:99";

    }









    #
    #  Write out the stuff we need to the Data File. This is the file that will
    #  be read by wmWeather.
    #
    if ($Flag > 0){
        open(TmpFile, ">$DataFileName");
        print TmpFile "$StationInfo\n";
        print TmpFile "$UpdateTime\n";
        print TmpFile "$SkyConditions\n";
        print TmpFile "$UniversalTime\n";
        print TmpFile "$Temp\n";
        print TmpFile "$DewPnt\n";
        print TmpFile "$Chill\n";
        print TmpFile "$Pressure\n";
        print TmpFile "$Hum\n";

	if ($Direction eq "" ){
	    print TmpFile "-9999\n";
	} elsif ($Direction =~ /VRB/ ){
	    print TmpFile "999\n";
	} elsif ($VarFlag) {
	    $Direction += 0;
	    print TmpFile "-$Direction\n";
	} else {
	    $Direction += 0;
	    print TmpFile "$Direction\n";
	}

	if ($WindGroup eq "" ) {
	    print TmpFile "-9999\n";
	} elsif ($GustFlag) {
	    $AvgSpeed = ($Speed1 + $Speed2)/2.0;
	    $AvgSpeed *= 1.15155;
	    print TmpFile "-$AvgSpeed\n";
	} else {
	    $Speed += 0;
	    $Speed *= 1.15155;
	    print TmpFile "$Speed\n";
	}

        close(TmpFile);
    }