#! /usr/bin/perl -w

use strict;
use warnings;
use utf8;

## IMPORTANT ##
# When Net::Twitter::Lite encounters a Twitter API error or a network error, 
# it throws a Net::Twitter::Lite::Error object. 
# You can catch and process these exceptions by using eval blocks and testing $@
## from http://search.cpan.org/perldoc?Net::Twitter::Lite#ERROR_HANDLING
use Net::Twitter::Lite;
use FindBin qw($Bin);
use YAML::Tiny;

sub VERBOSE () { $ARGV[0] eq 'verbose' };
sub DEBUG   () { VERBOSE or $ARGV[0] eq 'debug' };
use Data::Dumper;

DEBUG and warn "$0: debug mode";

my $conf = loadconf("$Bin/config.yml");
if (! defined $conf) {
    die "$0: cannot parse config file.\n";
}
my $stat = loadconf("$Bin/status.yml");
if (! defined $stat) {
    $stat = {};
}

my $bot = login($conf);
if (! $bot->authorized) {
    die "$0: this client is not yet authorized.\n";
}

my $tweets = {};
my $tweet;

$tweet = or_search($bot, $conf->{hashtag}, $stat->{search});
if ($tweet) {
    %$tweets = (%$tweets, %$tweet);
}

$tweet = mentions_ids($bot, $stat->{mention});
if ($tweet) {
    %$tweets = (%$tweets, %$tweet);
}

foreach my $id (sort keys %$tweets) {
    # $tweets->{$id}{type} eq 'search'  => found by search API
    #                      eq 'mention' => found by mention API
    if ($tweets->{$id}{type} eq 'retweet') {
        next;
    }
    DEBUG or sleep($conf->{sleep});
    
    # do retweet found tweets
    my $res;
    eval {
        DEBUG  or $res = $bot->retweet($id);
        DEBUG and warn "retweet($id) => ", Dumper($tweets->{$id});
    };
    if ($@) {
        evalrescue($@);
        warn "status_id => $id\n";
        next;
    }
    
    $stat->{$tweets->{$id}{type}} = $id;
}

if ($tweets) {
    # save last status to yaml file
    DEBUG  or YAML::Tiny::DumpFile("$Bin/status.yml", $stat);
    DEBUG and warn "status.yml => ", Dumper($stat);
}


sub loadconf {
    # load configration data from yaml formatted file
    #   param   => scalar string of filename
    #   ret     => hash object of yaml data
    
    my $file = shift @_;
    
    my $yaml = YAML::Tiny->read($file);
    
    if ($!) {
        warn "$0: '$file' $!\n";
    }
    
    return $yaml->[0];
}

sub login {
    # make Net::Twitter::Lite object and login
    #   param   => hash object of configration
    #   ret     => Net::Twitter::Lite object
    
    my $conf = shift @_;
    
    my $bot = Net::Twitter::Lite->new(
        consumer_key    => $conf->{consumer_key},
        consumer_secret => $conf->{consumer_secret},
    );
    
    $bot->access_token($conf->{access_token});
    $bot->access_token_secret($conf->{access_token_secret});
    
    return $bot;
}

sub or_search {
    # search tweets containing keywords
    #   param   => Net::Twitter::Lite object, ArrayRef of keywords, since_id
    #   ret     => HashRef of status_id (timeline order is destroyed)
    #               or undef (none is found)
    
    my $bot      = shift @_;
    my $keywords = shift @_;
    my $since_id = shift @_ || 1;
    
    my $key = "";
    foreach my $word (@$keywords) {
        if ($key) {
            $key .= " OR $word";
        }
        else {
            $key = $word;
        }
    }
    DEBUG and warn "searching '$key'";
    
    my $res;
    my $ids = {};
    eval {
        if ($key) {
            $res = $bot->search(
                {
                    q           => $key,
                    since_id    => $since_id,
                }
            );
        }
        if ($res->{results}) {
            VERBOSE and warn Dumper($res);
            foreach my $tweet (@{$res->{results}}) {
                my $res = $bot->show_status($tweet->{id});
                if ($res->{retweeted_status}) {
                    $ids->{$tweet->{id}}{type} = 'retweet';
                }
                else {
                    $ids->{$tweet->{id}}{type} = 'search';
                }
                VERBOSE and warn Dumper($res);
            }
        }
    };
    if ($@) {
        evalrescue($@);
    }
    
    DEBUG and warn "search result => ", Dumper($ids);
    return $ids;
}

sub mentions_ids {
    # return status_ids mentioned to me
    #   param   => Net::Twitter::Lite object, since_id
    #   ret     => HashRef of status_id (timeline order is destroyed)
    #               or undef (none is found)
    
    my $bot      = shift @_;
    my $since_id = shift @_ || 1;
    
    my $res;
    eval {
        $res = $bot->mentions(
            {
                since_id    => $since_id,
            }
        );
        VERBOSE and warn Dumper($res);
    };
    if ($@) {
        evalrescue($@);
    }
    
    my $ids = {};
    if ($res && @{$res}) {
        $ids = {
            map {
                $_->{id} => {
                    type => 'mention',
                }
            } @{$res}
        };
    }
    
    DEBUG and warn "mentions result => ", Dumper($ids);
    return $ids;
}

sub evalrescue {
    # output error message at eval error
    
    use Scalar::Util qw(blessed);
    
    if (blessed $@ && $@->isa('Net::Twitter::Lite::Error')) {
        warn $@->error;
        if ($@->twitter_error) {
            my %twitter_error = %{$@->twitter_error};
            map {
                $twitter_error{"$_ => "} = $twitter_error{$_} . "\n";
                delete $twitter_error{$_}
            } keys %twitter_error;
            warn join("", %twitter_error);
        }
    }
    else {
        warn $@;
    }
}