#!/usr/bin/perl -w

# Copyright Dmitri Vassilenko (dv [at] glyphy [dot] com)
# Personal use is OK. Keep the ownership info.

# Needs to be called from cron (or whatever you have) once in a while.
# Upon each successive call with no arguments, it will query del.icio.us
# for new posts under a certain tag and store the fetched data on disk along
# with the last post time. Naturally, you shouldn't run this in a tight loop.
# I run this a couple of times a day. You may get throttled by del.icio.us if
# you poll too often.
# To force a post, use the -u cmd-line option.
# If you post a lot, you may wish to append "&count=n" to $DEL_API, where n
# is the number of posts you'd like to fetch. The default is 15 and max is 100.

### Requirements
use strict;
use Getopt::Std;
use Data::Dumper;
use LWP::UserAgent;
use XML::Simple;
use Storable;
use DateTime::Format::W3CDTF;
use Mail::Send;

########## Define constants ##########
use constant LJ_USERNAME  => 'YourLJUsername';
use constant LJ_PIN       => 'YourLJEmailPostingPin';
my  $DEL_USERNAME          = 'YourDeliciousUsername';
my  $DEL_PASSWORD          = 'YourDeliciousPassword';
my  $DEL_TAG               = 'postingTag';

# changing the following is optional
my  $DEL_API = "https://api.del.icio.us/v1/posts/recent?tag=$DEL_TAG";
use constant TIME_FILE    => '/home/you/last'; # stores last update time
use constant POSTS_FILE   => '/home/you/posts'; # stores queued items for posting
use constant MAX_DOC_SIZE => 100000; # in bytes
use constant TIMEOUT      => 10;
use constant MAX_POSTS    => 7; # after this # of new items, an lj-cut is used
use constant MIN_POSTS    => 3; # don't post less than this # of items
######################################

sub usage {
  print "Usage: ljdelpost [-u] [-s] [-t n]
Fetches the last few posts from del.icio.us and stores them on disk.
      -u updates and forces a post
      -s shows the latest posts currently stored on disk without posting them
      -t n trims the posts list to n last posts\n";
}

# Parse commands
my $cmds = getopts('usht:');
our($opt_h, $opt_s, $opt_u, $opt_t);
if (defined $opt_h) { usage(); exit 0 }

########## Fetch stored data from disk ##########
if (! -e TIME_FILE) {
  my $initial_time = 0;
  store(\$initial_time, TIME_FILE);
}
my $last = retrieve(TIME_FILE); # Last update time from epoch

if (! -e POSTS_FILE) {
  my @initial_posts;
  store(\@initial_posts, POSTS_FILE);
}
my $sposts = retrieve(POSTS_FILE); # Posts stored on disk
#################################################

if (defined $opt_t) {
	splice(@{$sposts}, $opt_t);
	store($sposts, POSTS_FILE) or die "Can't store %a in " . POSTS_FILE . "\n";
	$opt_s = 1;
}

if (defined $opt_s) {
  print "Stored posts:\n";
  print Dumper($sposts);
  exit 0;
}

my $ua = new LWP::UserAgent;
my $content;

$ua->max_size(MAX_DOC_SIZE);
$ua->timeout(TIMEOUT);
$ua->agent("LJDelPost (http://www.livejournal.com/users/troworld/162341.html)");

my $req = new HTTP::Request GET => $DEL_API;
$req->authorization_basic($DEL_USERNAME, $DEL_PASSWORD);
my $res;

while ($res = $ua->request($req)) {
  if ($res->is_success) {
    $content = $res->content;
    last;
  } else {
    warn "Error: " . $res->code . ' ' . $res->message;
    exit 1 if ($res->code == 503 || $res->code == 401); # Back off
    sleep 60;
  }
}

my $posts = XMLin($content, ForceArray => 1)->{post};
my $f = DateTime::Format::W3CDTF->new;

my $dt; # Date of $i'th post
my @newposts; # will be copied to disk when complete
my $newtime = $f->parse_datetime($posts->[0]->{time}); # date of last new post
foreach my $i (@{$posts}) {
  $dt = $f->parse_datetime($i->{time});
  last unless ($dt->epoch() > ${$last}); # Posts are in descending order sorted
                                         # by time
  push @newposts, $i;
}

# Copy new posts to disk
if ($#newposts >= 0) {
  unshift @{$sposts}, @newposts;
  store($sposts, POSTS_FILE) or die "Can't store %a in " . POSTS_FILE . "\n";
  store(\$newtime->epoch(), TIME_FILE) or die "Can't store %a in " . TIME_FILE . "\n"; # update last post time
}

if (defined $opt_u) {
  if ($#{$sposts} < 0 || $#{$sposts} < MIN_POSTS) {
    warn 'Not enough new posts. Not sending any messages.';
    exit 0;
  }
  my $msg = new Mail::Send;
  $msg->to(LJ_USERNAME . '+' . LJ_PIN . '@post.livejournal.com');
  #$msg->cc('your@email.com'); # CC yourself
  $msg->subject('Links for ' . $newtime->day . ' ' . $newtime->month_name . ' ' . $newtime->year);
  my $mailer = $msg->open;
  #open(my $mailer, '>-'); # for debugging purposes
  
  print $mailer "lj-security: public\nlj-tags: links\nlj-userpic: default\n\n";
  print $mailer "<lj-cut text=\"" . @{$sposts} . " links\">" if ($#{$sposts}+1 > MAX_POSTS);
  print $mailer "<lj-raw>\n<ul class='delList'>\n";
  
  foreach my $i (reverse @{$sposts}) {
    my $posted_time = $f->parse_datetime($i->{time});
    print $mailer '    <li class="delPost">
        <a href="' . $i->{href} .
    '">' . $i->{description} . '</a> <small>(Posted on ' . $posted_time->day . ' ' . $posted_time->month_name . ' ' . $posted_time->year . ' @ ' . $posted_time->hms . ' ' . $posted_time->time_zone_short_name . ")</small>\n";
    print $mailer '        <div class="delExt">' . $i->{extended} . "</div>\n" if (exists $i->{extended});
    my $tagline = $i->{tag};
    $tagline =~ s|$DEL_TAG||; # kill the lj tag
    if (length $tagline > 0) {
      my @tags = split(' ', $tagline);
      print $mailer '        <div class="delTags">Tags: ';
      foreach my $j (@tags) {
        print $mailer '<a href="http://del.icio.us/' . $DEL_USERNAME . "/$j\">$j</a> ";
      }
      print $mailer "</div>\n";
    }
    print $mailer "    </li>\n";
  }
  print $mailer "</ul>\n";
  print $mailer '</lj-raw>';
  print $mailer "</lj-cut>\n" if ($#{$sposts}+1 > MAX_POSTS);
  $mailer->close; # Send the message
  
  my @cleanposts;
  store(\@cleanposts, POSTS_FILE) or die "Can't store %a in " . POSTS_FILE . "\n";
}