Send wind even if it hasn't changed
[dweather.git] / loop.pl
1 #!/usr/bin/perl
2 use strict;
3
4 use v5.10.1;
5
6 use Mojolicious::Lite;
7 use Serial;
8 use Mojo::IOLoop;
9 use Mojo::IOLoop::Stream;
10 use Mojo::Transaction::WebSocket;
11 #use Mojo::JSON  qw(decode_json encode_json);
12 use JSON;
13 use Debug;
14 use SMGLog;
15 use Math::Round qw(nearest);
16 use File::Copy;
17 use Data::Random qw(rand_chars);
18 use IO::File;
19
20 use constant pi => 3.14159265358979; 
21
22 my $randomfn = '/dev/urandom';
23 my $devname = "/dev/davis";
24 my $datafn = ".loop_data";
25 my $dataf;
26
27 my $poll_interval = 2.5;
28 my $rain_mult = 0.2;                            # 0.1 or 0.2 mm or 0.01 inches
29 my $tid;
30 my $rid;
31 our $did;
32 my $nlcount;
33 my $state = "ready";
34 my $buf;
35 my $dbg;
36 our $ser;                                                       # the serial port Mojo::IOLoop::Stream
37 our $ob;                                                        # the Serial Port filehandle
38 my $last_min_h;
39 my $last_hour_h;
40
41 our $json = JSON->new->canonical(1);
42 our $WS = {};                                   # websocket connections
43
44 our $ld = {};
45 our @last10minsr = ();
46 our @last5daysh = ();
47 our $windmins = 2;                              # no of minutes of wind data for the windrose
48 our $histdays = 5;                              # no of days of (half)hour data to search for main graph
49 our $updatepermin = 60 / 2.5;   # no of updates per minute
50
51 our $loop_count;                                # how many LOOPs we have done, used as start indicator
52
53 our     @crc_table = (
54                                   0x0, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
55                                   0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
56                                   0x1231, 0x210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
57                                   0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
58                                   0x2462, 0x3443, 0x420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
59                                   0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
60                                   0x3653, 0x2672, 0x1611, 0x630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
61                                   0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
62                                   0x48c4, 0x58e5, 0x6886, 0x78a7, 0x840, 0x1861, 0x2802, 0x3823,
63                                   0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
64                                   0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0xa50, 0x3a33, 0x2a12,
65                                   0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
66                                   0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0xc60, 0x1c41,
67                                   0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
68                                   0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0xe70,
69                                   0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
70                                   0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
71                                   0x1080, 0xa1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
72                                   0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
73                                   0x2b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
74                                   0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
75                                   0x34e2, 0x24c3, 0x14a0, 0x481, 0x7466, 0x6447, 0x5424, 0x4405,
76                                   0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
77                                   0x26d3, 0x36f2, 0x691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
78                                   0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
79                                   0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x8e1, 0x3882, 0x28a3,
80                                   0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
81                                   0x4a75, 0x5a54, 0x6a37, 0x7a16, 0xaf1, 0x1ad0, 0x2ab3, 0x3a92,
82                                   0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
83                                   0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0xcc1,
84                                   0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
85                                   0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0xed1, 0x1ef0
86                                  );
87
88 our %bar_trend;
89
90 $bar_trend{-60} = "Falling Rapidly";
91 $bar_trend{196} = "Falling Rapidly";
92 $bar_trend{-20} = "Falling Slowly";
93 $bar_trend{236} = "Falling Slowly";
94 $bar_trend{0} = "Steady";
95 $bar_trend{20} = "Rising Slowly";
96 $bar_trend{60} = "Rising Rapidly";
97
98 our $ending = 0;
99
100 $SIG{TERM} = $SIG{INT} = sub {$ending = 1; Mojo::IOLoop->stop;};
101 $SIG{HUP} = 'IGNORE';
102
103
104 # WebSocket weather service
105 websocket '/weather' => sub {
106   my $c = shift;
107   my $msg = shift;
108   my $tx = $c->tx;
109
110   # Opened
111   app->log->debug('WebSocket opened.');
112   dbg 'WebSocket opened' if isdbg 'chan';
113   $WS->{$tx} = $tx; 
114
115   # send historical data
116   $c->send($ld->{lasthour_h}) if exists $ld->{lasthour_h};
117   $c->send($ld->{lastmin_h}) if exists $ld->{lastmin_h};
118
119   # disable timeout
120   $c->inactivity_timeout(3615);
121  
122   # Incoming message
123   $c->on(
124                  message => sub {
125                          my ($c, $msg) = @_;
126                          dbg "websocket: text $msg" if isdbg 'chan';
127                  },
128                  json => sub {
129                          my ($c, $msg) = @_;
130                          dbg "websocket: json $msg" if isdbg 'chan';
131                  }
132   );
133  
134   # Closed
135   $c->on(finish => sub {
136     my ($c, $code, $reason) = @_;
137     app->log->debug("WebSocket closed with status $code.");
138         dbg "websocket closed with status $code" if isdbg 'chan';
139         delete $WS->{$tx};
140   });
141 };
142
143 get '/' => {template => 'index'};
144
145
146 dbginit();
147 if (@ARGV) {
148         dbgadd(@ARGV);
149
150 dbgadd('chan');
151
152 dbg '***';
153 dbg "*** starting $0";
154 dbg '***';
155
156 read_ld();
157
158 my $tnow = time;
159 my $dayno = int ($tnow/86400);
160 for (my $i = 0-$histdays; $i < 0; ++$i ) {
161         push @last5daysh, grab_history(SMGLog->new("day"), "h", $tnow-(86400*$histdays), $dayno+$i+1); 
162 }
163 @last10minsr = map {my ($t, $js) = split(/\s/, $_, 2); $js} grab_history(SMGLog->new("debug"), "r", $tnow-(60*$windmins), $dayno);
164 dbg sprintf("last5days = %d last10mins = %d", scalar @last5daysh, scalar @last10minsr);
165
166 sysopen(R, $randomfn, 0) or die "cannot open $randomfn $!\n";
167 my $rs;
168 sysread(R, $rs, 8) or die "not enough randomness available\n";
169 close R;
170
171 app->secrets([qw(Here's something that's really seakrett), $rs]);
172
173 our $dlog = SMGLog->new("day");
174 $did = Mojo::IOLoop->recurring(1 => sub {$dlog->flushall});
175
176 dbg "before next tick";
177 Mojo::IOLoop->next_tick(sub { loop() });        
178 dbg "before app start";
179 app->start;
180 dbg "after app start";
181
182 doclose();
183
184 write_ld();
185 $dataf->close if $dataf;
186 undef $dataf;
187
188
189 # move all the files along one 
190 cycle_loop_data_files();
191
192 dbg '***';
193 dbg "*** ending $0 (\$ending = $ending)";
194 dbg '***';
195
196 exit 0;
197
198 ##################################################################################
199         
200 sub loop
201 {
202         dbg "last_min: " . scalar gmtime($ld->{last_min});
203         dbg "last_hour: " . scalar gmtime($ld->{last_hour});
204         
205         $ser = doopen($devname);
206         start_loop() if $ser;
207 }
208
209
210
211 sub on_read
212 {
213         my ($ser, $d) = @_;
214         $buf .= $d;
215         $d =~ s/([\%\x00-\x1f\x7f-\xff])/sprintf("%%%02X", ord($1))/eg; 
216         dbg "read added '$d' buf lth=" . length $buf if isdbg 'raw';
217         if ($state eq 'waitnl' && $buf =~ /[\cJ\cM]+/) {
218                 dbg "Got \\n" if isdbg 'state';
219                 Mojo::IOLoop->remove($tid) if $tid;
220                 undef $tid;
221                 undef $buf;
222                 $nlcount = 0;
223                 $ser->write("LPS 1 1\n");
224                 chgstate("waitloop");
225         } elsif ($state eq "waitloop") {
226                 if ($buf =~ /\x06/) {
227                         dbg "Got ACK 0x06" if isdbg 'state';
228                         chgstate('waitlooprec');
229                         undef $buf;
230                 }
231         } elsif ($state eq 'waitlooprec') {
232                 if (length $buf >= 99) {
233                         dbg "got loop record" if isdbg 'chan';
234                         chgstate('');
235                         process($buf);
236                         undef $buf;
237                 }
238         }
239 }
240
241 sub start_loop
242 {
243         $nlcount = 1;
244         dbg "start_loop writing $nlcount \\n" if isdbg 'state';
245         $ser->write("\n");
246         Mojo::IOLoop->remove($tid) if $tid;
247         undef $tid;
248         $tid = Mojo::IOLoop->recurring(0.6 => sub {
249                                                                            if (++$nlcount > 10) {
250                                                                                    doclose();
251                                                                                    return;
252                                                                            }
253                                                                            dbg "writing $nlcount \\n" if isdbg 'state'; 
254                                                                            $ser->write("\n");
255                                                                    });
256         chgstate("waitnl");
257 }
258
259 sub chgstate
260 {
261         dbg "state '$state' -> '$_[0]'" if isdbg 'state';
262         $state = $_[0];
263 }
264
265 my $closing;
266
267 sub doopen
268 {
269         my $name = shift;
270
271     $ob = Serial->new($name, 19200) || die "$name $!\n";
272         dbg "streaming $name fileno(" . fileno($ob) . ")" if isdbg 'chan';
273         
274         my $ser = Mojo::IOLoop::Stream->new($ob);
275         $ser->on(error=>sub {dbg "error serial $_[1]"; doclose();});
276         $ser->on(close=>sub {dbg "event close";  doclose();});
277         $ser->on(timeout=>sub {dbg "event serial timeout"; doclose();});
278         $ser->on(read=>sub {on_read(@_)});
279         $ser->start;
280
281     $rid = Mojo::IOLoop->recurring($poll_interval => sub {
282                                        start_loop() if !$state;
283                                    });
284
285         chgstate('');
286         $nlcount = 0;
287         
288         return $ser;
289 }
290
291 sub doclose
292 {
293         return if $closing++;
294         
295         dbg "serial port closing" if $ser || $ob;
296         if ($ser) {
297                 $ser->stop;
298                 $ser->close;
299                 undef $ser;
300         }
301         if ($ob) {
302                 $ob->close();
303                 undef $ob;
304         }
305         Mojo::IOLoop->remove($tid) if $tid;
306         undef $tid;
307         Mojo::IOLoop->remove($rid) if $rid;
308         undef $rid;
309
310     if (Mojo::IOLoop->is_running && $ending == 0) {
311                 Mojo::IOLoop->delay(
312                                                         sub {
313                                                                 my $delay = shift;
314                                                                 Mojo::IOLoop->timer(5 => $delay->begin);
315                                                                 dbg "Waiting 5 seconds before opening serial port";
316                                                          },
317
318                                                         sub {
319                                                                 dbg "Opening Serial port";
320                                                                 $ser = doopen($devname);
321                                                                 $closing = 0;
322                                                         }
323                                                    )->wait;
324         }
325         chgstate('');
326         $nlcount = 0;
327 }
328
329 my @min;
330 my @hour;
331
332 sub process
333 {
334         my $blk = shift;
335         my $loo =  substr $blk,0,3;
336         unless ( $loo eq 'LOO') {
337                 dbg "Block invalid loo -> $loo" if isdbg 'chan'; return;
338         }
339
340         my $tmp;
341         my $temp;
342         my $rain;
343         my %h;
344
345         my $crc_calc = CRC_CCITT($blk);
346
347         if ($crc_calc==0) {
348
349                 # Common ones
350                 $tmp = unpack("s", substr $blk,7,2) / 1000;
351                 $h{Pressure} = nearest(0.1, in2mb($tmp));
352
353                 $tmp = unpack("s", substr $blk,9,2) / 10;
354                 $h{Temp_In} = nearest(0.1, f2c($tmp));
355
356                 $temp  = nearest(0.1, f2c(unpack("s", substr $blk,12,2) / 10));
357                 $h{Temp_Out}  = $temp;
358                 if ($temp > 60 || $temp < -60) {
359                         dbg "LOOP Temperature out of range ($temp), record ignored";
360                         return;
361                 }
362
363                 $tmp = unpack("C", substr $blk,14,1);
364                 $h{Wind} = nearest(0.1, mph2mps($tmp));
365                 $h{Dir}     = unpack("s", substr $blk,16,2)+0;
366
367                 my $wind = {w => $h{Wind}, d => $h{Dir}};
368                 $wind = 0 if $wind == 255;
369                 push @{$ld->{wind_min}}, $wind;
370
371                 $tmp = int(unpack("C", substr $blk,33,1)+0);
372                 if ($tmp > 100) {
373                         dbg "LOOP Outside Humidity out of range ($tmp), record ignored";
374                         return;
375                 }
376                 $h{Humidity_Out} = $tmp;
377                 $tmp = int(unpack("C", substr $blk,11,1)+0);
378                 if ($tmp > 100) {
379                         dbg "LOOP Inside Humidity out of range ($tmp), record ignored";
380                         return;
381                 }
382                 $h{Humidity_In}  = $tmp;
383                 
384
385                 $tmp = unpack("C", substr $blk,43,1)+0;
386                 $h{UV} = $tmp unless $tmp >= 255;
387                 $tmp = unpack("s", substr $blk,44,2)+0; # watt/m**2
388                 $h{Solar} = $tmp unless $tmp >= 32767;
389
390                 #       $h{Rain_Rate}  = nearest(0.1,unpack("s", substr $blk,41,2) * $rain_mult);
391                 $rain = $h{Rain_Day}   = nearest(0.1, unpack("s", substr $blk,50,2) * $rain_mult);
392                 my $delta_rain = $h{Rain} = nearest(0.1, ($rain >= $ld->{last_rain} ? $rain - $ld->{last_rain} : $rain)) if $loop_count;
393                 $ld->{last_rain} = $rain;
394
395                 # what sort of packet is it?
396                 my $sort =  unpack("C", substr $blk,4,1);
397                 if ($sort) {
398
399                         # Newer LOOP2 packet
400                         $tmp = unpack("C", substr $blk,18,2);
401                         #               $h{Wind_Avg_10} = nearest(0.1,mph2mps($tmp/10));
402                         $tmp = unpack("C", substr $blk,20,2);
403                         #               $h{Wind_Avg_2} = nearest(0.1,mph2mps($tmp/10));
404                         $tmp = unpack("C", substr $blk,22,2);
405                         #               $h{Wind_Gust_10} = nearest(0.1,mph2mps($tmp/10));
406
407                         #               $h{Dir_Avg_10} = unpack("C", substr $blk,24,2)+0;
408                         $tmp = unpack("C", substr $blk,30,2);
409                         $h{Dew_Point} = nearest(0.1, f2c($tmp));
410
411                 } else {
412
413                         # Older LOOP packet
414                         $tmp = unpack("C", substr $blk,15,1);
415                         #               $h{Wind_Avg_10} = nearest(0.1,mph2mps($tmp));
416                         $h{Dew_Point}  = nearest(0.1, dew_point($h{Temp_Out}, $h{Humidity_Out}));
417                         $h{Rain_Month}  = nearest(0.1, unpack("s", substr $blk,52,2) * $rain_mult);
418                         $h{Rain_Year}  = nearest(0.1, unpack("s", substr $blk,54,2) * $rain_mult);
419                 }
420
421                 my $ts = time;
422                 my $s;
423                 my $dayno = int($ts/86400);
424                 my $writeld;
425                 my $cycledata;
426                 
427                 if ($dayno > $ld->{last_day}) {
428                         $ld->{Wind_Max} = $wind->{w};
429                         $ld->{Temp_Out_Max} = $ld->{Temp_Out_Min} = $temp;
430                         $ld->{Temp_Out_Max_T} = $ld->{Temp_Out_Min_T} = $ld->{Wind_Max_T} = clocktime($ts, 0);
431                         $ld->{last_day} = $dayno;
432                         ++$writeld;
433                         ++$cycledata;
434                 }
435                 if ($temp > $ld->{Temp_Out_Max}) {
436                         $h{Temp_Out_Max} = $ld->{Temp_Out_Max} = $temp;
437                         $h{Temp_Out_Max_T} = $ld->{Temp_Out_Max_T} = clocktime($ts, 0);
438                         ++$writeld;
439                 }
440                 if ($temp < $ld->{Temp_Out_Min}) {
441                         $h{Temp_Out_Min} = $ld->{Temp_Out_Min} = $temp;
442                         $h{Temp_Out_Min_T} = $ld->{Temp_Out_Min_T} = clocktime($ts, 0);
443                         ++$writeld;
444                 }
445
446                 if ($wind->{w} > $ld->{Wind_Max}) {
447                         $h{Wind_Max} = $ld->{Wind_Max} = $wind->{w};
448                         $h{Wind_Max_T} = $ld->{Wind_Max_T} = clocktime($ts, 0);
449                         ++$writeld;
450                 }
451
452
453                 if ($ts >= $ld->{last_hour} + 1800) {
454                         $h{Pressure_Trend}    = unpack("C", substr $blk,3,1);
455                         $h{Pressure_Trend_txt} = $bar_trend{$h{Pressure_Trend}};
456                         $h{Batt_TX_OK}  = (unpack("C", substr $blk,86,1)+0) ^ 1;
457                         $h{Batt_Console}  = nearest(0.01, unpack("s", substr $blk,87,2) * 0.005859375);
458                         $h{Forecast_Icon}  = unpack("C", substr $blk,89,1);
459                         $h{Forecast_Rule}  = unpack("C", substr $blk,90,1);
460                         $h{Sunrise}  = sprintf( "%04d", unpack("S", substr $blk,91,2) );
461                         $h{Sunrise}  =~ s/(\d{2})(\d{2})/$1:$2/;
462                         $h{Sunset}   = sprintf( "%04d", unpack("S", substr $blk,93,2) );
463                         $h{Sunset}  =~ s/(\d{2})(\d{2})/$1:$2/;
464
465                         if ($loop_count) {      # i.e not the first
466                                 my $a = wind_average(scalar @{$ld->{wind_hour}} ? @{$ld->{wind_hour}} : {w => $h{Wind}, d => $h{Dir}});
467
468                                 $h{Wind_1h} = nearest(0.1, $a->{w});
469                                 $h{Dir_1h} = nearest(0.1, $a->{d});
470
471                                 $a = wind_average(@{$ld->{wind_min}});
472                                 $h{Wind_1m} = nearest(0.1, $a->{w});
473                                 $h{Dir_1m} = nearest(1, $a->{d});
474
475                                 ($h{Rain_1m}, $h{Rain_1h}, $h{Rain_24h}) = calc_rain($rain);
476                                 
477                         }
478                         $ld->{last_rain_min} = $ld->{last_rain_hour} = $rain;
479                         $h{Temp_Out_Max} = $ld->{Temp_Out_Max};
480                         $h{Temp_Out_Max_T} = $ld->{Temp_Out_Max_T};
481                         $h{Temp_Out_Min} = $ld->{Temp_Out_Min};
482                         $h{Temp_Out_Min_T} = $ld->{Temp_Out_Min_T};
483                         $h{Wind_Max} = $ld->{Wind_Max};
484                         $h{Wind_Max_T} = $ld->{Wind_Max_T};
485
486                         $last_hour_h = {%h};
487                         $s = genstr($ts, 'h', \%h);
488                         $ld->{lasthour_h} = $s;
489                         
490                         $ld->{last_hour} = int($ts/1800)*1800;
491                         $ld->{last_min} = int($ts/60)*60;
492                         @{$ld->{wind_hour}} = ();
493                         @{$ld->{wind_min}} = ();
494
495                         if ($s) {
496                                 output_str($s, 1);
497                                 push @last5daysh, $s;
498                                 shift @last5daysh if @last5daysh > 5*24;
499                         }
500                         ++$writeld;
501                         
502                 } elsif ($ts >= $ld->{last_min} + 60) {
503                         my $a = wind_average(@{$ld->{wind_min}});
504                         my %save;
505
506                         push @{$ld->{wind_hour}}, $a;
507
508                         if ($loop_count) {      # i.e not the first
509                                 my $rm;
510                                 
511                                 $h{Wind_1m} = nearest(0.1, $a->{w});
512                                 $h{Dir_1m} = nearest(1, $a->{d});
513                                 ($h{Rain_1m}, $h{Rain_1h}, $h{Rain_24h}) = calc_rain($rain);
514
515                                 my $wkph = $a->{w} * 3.6;
516                                 $h{WindChill} = nearest(0.1, $a->{w} >= 1.2 ? 13.12 + 0.6215 * $temp - 11.37 * $wkph ** 0.16 + 0.3965 * $temp * $wkph ** 0.16 : $temp); 
517                         }
518                         $ld->{last_rain_min} = $rain;
519                         $h{Temp_Out_Max} = $ld->{Temp_Out_Max};
520                         $h{Temp_Out_Max_T} = $ld->{Temp_Out_Max_T};
521                         $h{Temp_Out_Min} = $ld->{Temp_Out_Min};
522                         $h{Temp_Out_Min_T} = $ld->{Temp_Out_Min_T};
523                         $h{Wind_Max} = $ld->{Wind_Max};
524                         $h{Wind_Max_T} = $ld->{Wind_Max_T};
525
526                         $last_min_h = {%h};
527                         $s = genstr($ts, 'm', \%h);
528                         $ld->{lastmin_h} = $s;
529                         
530                         $ld->{last_min} = int($ts/60)*60;
531                         @{$ld->{wind_min}} = ();
532                         
533                         output_str($s, 1) if $s;
534                         ++$writeld;
535
536                 } else {
537                         my $o = gen_hash_diff($ld->{last_h}, \%h);
538                         $o ||= {};
539                         # we always send wind even if it hasn't changed in order to update the wind rose.
540                         $o->{Dir} ||= ($h{Dir} + 0);
541                         $o->{Wind} ||= ($h{Wind} + 0);
542                         $s = genstr($ts, 'r', $o);
543                         push @last10minsr, $s;
544                         shift @last10minsr while @last10minsr > ($windmins * $updatepermin);
545                         output_str($s, 0) if $s;
546                 }
547                 $ld->{last_h} = \%h;
548                 write_ld() if $writeld;
549                 cycle_loop_data_files() if $cycledata;
550                 ++$loop_count;
551         } else {
552                 dbg "CRC check failed for LOOP data!";
553         }
554         return;
555 }
556
557 sub genstr
558 {
559         my $ts = shift;
560         my $let = shift;
561         my $h = shift;
562         
563         my $j =  $json->encode($h);
564         my $tm = clocktime($ts, 1);
565         return qq|{"tm":"$tm","t":$ts,"$let":$j}|;
566 }
567
568 sub clocktime
569 {
570         my $ts = shift;
571         my $secsreq = shift;
572         my ($sec,$min,$hr) = (gmtime $ts)[0,1,2];
573         my $s;
574         if ($secsreq) {
575                 $s = sprintf "%02d:%02d:%02d", $hr, $min, $sec;
576         } else {
577                 $s = sprintf "%02d:%02d", $hr, $min;
578         }
579         return $s;
580 }
581
582 sub output_str
583 {
584         my $s = shift;
585         my $logit = shift;
586         
587         dbg $s;
588 #       say $s;
589         $dlog->writenow($s) if $logit;
590         foreach my $ws (keys $WS) {
591                 my $tx = $WS->{$ws};
592                 if ($tx) {
593                         $tx->send($s);
594                 } else {
595                         delete $WS->{$tx};
596                 }
597         }
598 }
599
600 sub gen_hash_diff
601 {
602         my $last = shift;
603         my $now = shift;
604         my %o;
605         my $count;
606
607         while (my ($k, $v) = each %$now) {
608                 if (!exists $last->{$k} || $last->{$k} ne $now->{$k}) {
609                         $o{$k} = $v;
610                         ++$count;
611                 }
612         }
613         return $count ? \%o : undef;
614 }
615
616 sub dew_point
617 {
618         my $temp = shift @_;
619         my $rh   = shift @_;
620
621         #  Using the simplified approximation for dew point
622         #  Accurate to 1 degree C for humidities > 50 %
623         #  http://en.wikipedia.org/wiki/Dew_point
624
625         my $dewpoint = $temp - ((100 - $rh) / 5);
626
627         # this is the more complete one (which doesn't work)
628         #my $a = 6.1121;
629         #my $b = 18.678;
630         #my $c = 257.14;
631         #my $ytrh = log(($rh/100) + ($b * $temp) / ($c + $temp));
632         #my $dewpoint = ($c * $ytrh) / ($b - $ytrh); 
633
634         return $dewpoint;
635 }
636
637 sub CRC_CCITT
638 {
639     # Expects packed data...
640     my $data_str = shift @_;
641
642         my $crc = 0;
643         my @lst = split //, $data_str;
644         foreach my $data (@lst) {
645                 my $data = unpack("c",$data);
646
647                 my $crc_prev = $crc;
648                 my $index = $crc >> 8 ^ $data;
649                 my $lhs = $crc_table[$index];
650                 #print "lhs=$lhs, crc=$crc\n";
651                 my $rhs = ($crc << 8) & 0xFFFF;
652                 $crc = $lhs ^ $rhs;
653
654
655         }
656
657         return $crc;
658 }
659
660 sub f2c
661 {
662         return ($_[0] - 32) * 5/9;
663 }
664
665 sub mph2mps
666 {
667         return $_[0] * 0.44704;
668 }
669
670 sub in2mb
671 {
672         return $_[0] * 33.8637526;
673 }
674
675 sub wind_average
676 {
677         my ($sindir, $cosdir, $wind);
678         my $count;
679         
680         foreach my $r (@_) {
681                 $wind += $r->{w};
682                 $sindir += sin(d2r($r->{d})) * $r->{w};
683                 $cosdir += cos(d2r($r->{d})) * $r->{w};
684                 ++$count;
685         }
686
687         my $avhdg = r2d(atan2($sindir, $cosdir));
688         $avhdg += 360 if $avhdg < 0; 
689         return {w => nearest(0.1,$wind / $count), d => nearest(0.1,$avhdg)};
690 }
691
692 # radians to degrees
693 sub r2d
694 {
695     my $n = shift;
696     return ($n / pi) * 180;
697 }
698
699 # degrees to radians
700 sub d2r 
701 {
702     my $n = shift;
703     return ($n / 180) * pi;
704 }
705
706 sub calc_rain
707 {
708         my $rain = shift;
709         
710         $ld->{rain24} ||= [];
711         
712         my $Rain_1h = nearest(0.1, $rain >= $ld->{last_rain_hour} ? $rain - $ld->{last_rain_hour} : $rain); # this is the rate for this hour, so far
713         my $rm = nearest(0.1, $rain >= $ld->{last_rain_min} ? $rain - $ld->{last_rain_min} : $rain);
714         my $Rain_1m = nearest(0.1, $rm);
715         push @{$ld->{rain24}}, $Rain_1m;
716         $ld->{rain_24} += $rm;
717         while (@{$ld->{rain24}} > 24*60) {
718                 $ld->{rain_24} -= shift @{$ld->{rain24}};
719         }
720         my $Rain_24h = nearest(0.1, $ld->{rain_24});
721         return ($Rain_1m, $Rain_1h, $Rain_24h);
722 }
723
724 sub read_ld
725 {
726         unless ($dataf) {
727                 $dataf = IO::File->new("+>> $datafn") or die "cannot open $datafn $!";
728                 $dataf->autoflush(1);
729         }
730
731         seek $dataf, 0, 0;
732         my $s = <$dataf>;
733         chomp $s;
734         dbg "read loop data: $s" if isdbg 'json';
735         $ld = $json->decode($s) if length $s;
736         
737         # sort out rain stats
738         my $c;
739         if ($ld->{rain24} && ($c = @{$ld->{rain24}}) < 24*60) {
740                 my $diff = 24*60 - $c;
741                 unshift @{$ld->{rain24}}, 0 for 0 .. $diff;  
742         }
743         my $rain;
744         
745         if ($ld->{rain24}) {
746                 $rain += $_ for @{$ld->{rain24}};
747         }
748         
749         $ld->{rain_24} = nearest(0.1, $rain);
750         delete $ld->{hour};
751         delete $ld->{min};
752 }
753
754 sub write_ld
755 {
756         unless ($dataf) {
757                 $dataf = IO::File->new("+>> $datafn") or die "cannot open $datafn $!";
758                 $dataf->autoflush(1);
759         }
760
761         seek $dataf, 0, 0;
762         truncate $dataf, 0;
763         $ld->{ts} = time;
764         my $s = $json->encode($ld);
765         dbg "write loop data: $s" if isdbg 'json';
766         print $dataf "$s\n";
767 }
768
769 sub cycle_loop_data_files
770 {
771         $dataf->close if $dataf;
772         undef $dataf;
773         
774         rename "$datafn.oooo", "$datafn.ooooo";
775         rename "$datafn.ooo", "$datafn.oooo";
776         rename "$datafn.oo", "$datafn.ooo";
777         rename "$datafn.o", "$datafn.oo";
778         copy $datafn, "$datafn.o";
779 }
780
781 sub grab_history
782 {
783         my $lg = shift;
784         my $let = shift;
785         my $start = shift || time - 86400;
786         my $dayno = shift;
787         my @out;
788         
789         if ($lg->open($dayno, 'r+')) {
790                 while (my $l = $lg->read) {
791                         next unless $l =~ /,"$let":/;
792                         my ($t) = $l =~ /"t":(\d+)/;
793                         if ($t && $t >= $start) {
794                                 push @out, $l;
795                         }
796                 }
797                 $lg->close;
798         }
799         return @out;
800 }