#!/usr/bin/perl 

use v5.030;    # strictness implied
use warnings;
use feature qw[ signatures ];
no warnings qw[ experimental::signatures ];

use Astro::Coord::ECI::Utils 'deg2rad';
use Astro::Coords;
use Astro::MoonPhase;
use Astro::Telescope;
use DateTime;
use DateTime::Format::ISO8601;
use DateTime::TimeZone;
use Data::Dumper;
use Log::Log4perl;
use Try::Tiny;

######
# Calculate the moon phase of an event in time.
# Required is the date (time defaults to 00:00:01) of the event
# The moon-phase calculator does not need a location
# since moon phase is the same across the planet (more-or-less)
# with the usual antipodean side-effects
# However, by specifying a timezone or even coordinates of the
# event conversion of event's time to UTC is more accurate
# (else UTC time is assumed)
# author: bliako, modified by aldebaran
# date: 2021-10-10
######

my $debug    = 1;
my $time_str = "03:22:31";
my $alt      = 0;
my $date_str = "2021-10-14";

my @events = (

  #  {
  #    # example event specification
  #    "name" => "a name for reference, required",
  #    "date" => "date of the event in YYYY-MM-DD",
  #    "time" => "optional time as hh:mm:ss, default is 00:00:01",
  #    #specify optional location using one of these for calculating
  #    #epoch which uses UTC time,
  #    #otherwise, UTC timezone will be assumed for event's time:
  #    "timezone" => "standard timezone name, e.g. America/Havana",
  #    "location" => "cuba",
  #    "location" => {lon=>-81.137633, lat=>22.17927},
  #  },

  {
    "name"     => "in the 'Ho",
    "date"     => $date_str,
    "time"     => $time_str,
    "location" => { lon => -116.2, lat => 43.61 },
  },
  {
    "name"     => "on the Scylla",
    "date"     => $date_str,
    "time"     => $time_str,
    "location" => { lon => 38.245833, lat => 15.6325 },
  },
  {
    "name"     => "in Antipo' 'Ho",
    "date"     => $date_str,
    "time"     => $time_str,
    "location" => { lon => 63.8, lat => -43.61 },
  },
  {
    "name"     => "at Antipodlean Scylla",
    "date"     => $date_str,
    "time"     => $time_str,
    "location" => { lon => -141, lat => -15.6325 },
  },
);

# Not wanting to divine the configuration file for Log::Log4perl, module used in
# the query. Better for SSCCE considerations. thx parv
{

  package Log::Log4perl;
  sub get_logger ($pkg) { return bless [], $pkg; }

  sub show  (@arg)             { warn @arg, "\n"; }
  sub debug ( $ignore, @rest ) { show( 'DEBUG: ',   @rest ); }
  sub info  ( $ignore, @rest ) { show( 'INFO: ',    @rest ); }
  sub warn  ( $ignore, @rest ) { show( 'WARNING: ', @rest ); }

  sub error ( $ignore, @rest ) { die 'ERROR: ', @rest, "\n"; }
}

my $logger = Log::Log4perl->get_logger();
$logger->info("$0");

## event loop

for my $event (@events) {
  my $epoch = parse_event($event);

  my ( $MoonPhase, $MoonIllum, $MoonAge, $MoonDist, $MoonAng, $SunDist,
    $SunAng ) = phase($epoch);
  $logger->info("Moon age: $MoonAge days");
  $logger->info( "Moon phase: "
      . sprintf( "%.1f", 100.0 * $MoonPhase )
      . " % of cycle (birth-to-death)" );
  $logger->info( "Moon's illuminated fraction: ",
    sprintf( "%.1f", 100.0 * $MoonIllum ) . " % of full disc" );

## determine altitude
  # usage:
  die unless exists $event->{location};    # restriction
  my $return = get_elevation_from_coordinates( $event->{location}->{lat},
    $event->{location}->{lon}, 0 );
  $logger->info("return from the google is $return meters");
  my $observer = $return + 2;              #(most people stand)
  $logger->info( event2str($event) . " at height $observer  meters" );
  $logger->info("Object\tAzimuth\t\tElevation");
  for my $name (qw/Venus Jupiter Moon Saturn/) {

    my $planet = Astro::Coords->new( planet => $name );

    # use DateTime
    my $date = DateTime->from_epoch( epoch => $epoch, time_zone => 'UTC' );
    $planet->datetime($date);

    $planet->telescope(
      Astro::Telescope->new(
        Name => $event->{name},
        Long => deg2rad( $event->{location}->{lon} ),
        Lat  => deg2rad( $event->{location}->{lat} ),
        Alt  => $observer,                              #meters above sea level
      )
    );

    my $az = $planet->az( format => 'deg' );
    my $el = $planet->el( format => 'deg' );
    $logger->info("$name\t$az\t\t$el");

  }
  ## end planets loop
}
## end event loop

sub event2str {
  my $event = shift;

  if ( !exists $event->{_is_parsed} ) {
    warn "event has not been parsed, just dumping it...";
    print Dump($event);
  }
  my $str =
      $event->{name} . " on "
    . $event->{datetime} . " ("
    . $event->{datetime}->epoch
    . " seconds unix-epoch)"
    . " timezone: "
    . $event->{datetime}->time_zone->name;
  if ( exists $event->{location} ) {
    if ( ref( $event->{location} ) eq 'HASH' ) {
      $str .=
          " (lat: "
        . $event->{location}->{lat}
        . ", lon: "
        . $event->{location}->{lon} . ")";
    }
    else { $str .= "(" . $event->{location} . ")" }
  }
  return $str;
}

sub parse_event {
  my $event = shift;

  if ( !exists $event->{date} ) { die "date field is missing from event." }

  my $datestr = $event->{date};

  die "event does not have a 'name' field, please specify one, anything really."
    unless exists $event->{name};

  my $timestr = "00:00:01";
  if ( exists $event->{time} ) {
    $timestr = $event->{time};
    print "event2epoch(): setting time to '$timestr' ...\n"
      if $debug > 0;
    die "time '$timestr' is not valid, it must be in the form 'hh:mm:ss'."
      unless $timestr =~ /^\d{2}:\d{2}:\d{2}$/;
  }
  else { $event->{time} = $timestr }

  my $isostr = $datestr . 'T' . $timestr;
  my $dt     = DateTime::Format::ISO8601->parse_datetime($isostr);
  die "failed to parse date '$isostr', check date and time fields."
    unless defined $dt;
  $event->{datetime} = $dt;

  my $tzstr = 'UTC';
  if ( exists $event->{timezone} ) {
    $tzstr = $event->{timezone};
    print
"event2epoch(): found a timezone via 'timezone' field as '$tzstr' (that does not mean it is valid) ...\n"
      if $debug > 0;
  }
  elsif ( exists $event->{location} ) {
    my $loc = $event->{location};
    if ( ( ref($loc) eq '' ) && ( $loc =~ /^[a-zA-Z]$/ ) ) {

      # we have a location string
      my @alltzs = DateTime::TimeZone->all_names;
      my $tzstr;
      for (@alltzs) {
        if ( $_ =~ /$loc/i ) { $tzstr = $_; last }
      }
      die
"event's location can not be converted to a timezone, consider specifying the 'timezone' directly or setting 'location' coordinates with: \[lat,lon\]."
        unless $tzstr;
      print
"event2epoch(): setting timezone via 'location' name to '$timestr' ...\n"
        if $debug > 0;
    }
    elsif ( ( ref($loc) eq 'HASH' )
      && ( exists $loc->{lat} )
      && ( exists $loc->{lon} ) )
    {
      # we have a [lat,lon] array for location
      require Geo::Location::TimeZone;
      my $gltzobj = Geo::Location::TimeZone->new();
      $tzstr = $gltzobj->lookup( lat => $loc->{lat}, lon => $loc->{lon} );
      if ( !$tzstr ) {
        die "timezone lookup from location coordinates lat:"
          . $loc->{lat}
          . ", lon:"
          . $loc->{lon}
          . " has failed.";
      }
      print "event2epoch(): setting timezone via 'location' coordinates lat:"
        . $loc->{lat}
        . ", lon:"
        . $loc->{lon}
        . " ...\n"
        if $debug > 0;
    }
  }
  if ($tzstr) {
    print "event2epoch(): deduced timezone to '$tzstr' and setting it ...\n"
      if $debug > 0;
    try {
      $dt->set_time_zone($tzstr)
    }
    catch {
      die "$_\n failed to set the timezone '$tzstr', is it valid?"
    }
  }

  $event->{_is_parsed} = 1;
  $event->{epoch}      = $dt->epoch;
  return $event->{epoch};
}

sub get_elevation_from_coordinates {
  my ( $lat, $lon, $debug ) = @_;

  use LWP::UserAgent;
  use HTTP::Request;
  use Data::Roundtrip;

  $debug //= 0;

  my $ua = LWP::UserAgent->new( agent =>
      'Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Firefox/78.0', );

  my $response;
  my $payload =
      'latitude='
    . $lat
    . '&longitude='
    . $lon
    . '&application_max_assets_mtime=1559625591';
  my $payloadlen = length($payload);

  # this request was translated from Curl command-line
  # by [Corion]'s https://corion.net/curl2lwp.psgi
  my $req = HTTP::Request->new(
    'POST' =>
'https://www.mapcoordinates.net/admin/component/edit/Vpc_MapCoordinates_Advanced_GoogleMapCoords_Component/Component/json-get-elevation',
    [
      'Connection'      => 'keep-alive',
      'Accept'          => '*/*',
      'Accept-Encoding' => 'gzip, x-gzip, deflate, x-bzip2, bzip2',
      'Accept-Language' => 'en-US,en;q=0.5',

      #        'Host'            => 'www.mapcoordinates.net:443',
      'Referer'    => 'https://www.mapcoordinates.net/en',
      'User-Agent' =>
        'Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Firefox/78.0',
      'Content-Length'   => $payloadlen,
      'Content-Type'     => 'application/x-www-form-urlencoded; charset=UTF-8',
      'DNT'              => '1',
      'Origin'           => 'https://www.mapcoordinates.net',
      'X-Requested-With' => 'XMLHttpRequest'
    ],
    $payload
  );
  die "call to HTTP::Request has failed" unless $req;

  if ( $debug > 0 ) {
    print
      "$0 : $payload\n$0 : sending above payload, of $payloadlen bytes...\n";
  }

  $response = $ua->request($req);
  die "Error fetching: " . $response->status_line
    unless $response->is_success;

  my $content = $response->decoded_content;
  my $data    = Data::Roundtrip::json2perl($content);
  die "failed to parse received data:\n$content\n"
    unless exists $data->{'elevation'};

  return $data->{'elevation'};
}

__END__