#!/usr/bin/perl -w
use strict;
use warnings;
use DBI;
use DBD::SQLite::Constants qw/:file_open/;
use JSON;

my $dbpath = "./posts.db";
my $json = JSON->new;

sub get_info {
	my $clientIP = ($ENV{"REMOTE_ADDR"} or "0.0.0.0");
	my $proto = ($ENV{"REQUEST_SCHEME"} or "http");
	my $query = (split(/\?/,($ENV{"QUERY_STRING"} or "")))[0];
	my $referrer = ($ENV{"HTTP_REFERER"} or "");
	return ($proto,$clientIP,$query,$referrer);
}

sub http_status {
	my ($status,$content,$target) = @_;
	my $header = "";
	$header .= "status: ".$status."\r\n";
	$header .= "Location: ".$target."\r\n" if $target;
	$header .= "Content-Type: ".$content."\r\n" if $content;
	$header .= "\r\n";
	return $header;
}

sub soft_die {
	print http_status(500,"text/json");
	print '{"error":"'.shift.'"}';
	exit;
}

sub clean_input {
	my $input = shift;
	unless ($input) { return ""; }
	$input =~ s!%(..)!chr hex $1!ge;
	$input =~ s!\+! !g;
	$input =~ s!;!\;!g; #antivaxx
	return $input;
}

my $db = DBI->connect("DBI:SQLite:dbname=$dbpath", "", "", { RaiseError => 1, sqlite_open_flags => SQLITE_OPEN_READONLY }) or soft_die($DBI::errstr);
my $sth;

my @request = get_info();
my @get_params = split("&",clean_input($request[2]));
my $directive = shift(@get_params);
if ( "rand" eq $directive ) {
	# select a random post
	$sth = $db->prepare('SELECT * FROM posts ORDER BY RANDOM() LIMIT 1');
} elsif ( "last" eq $directive ) {
	# select the last post only
	$sth = $db->prepare('SELECT * FROM posts ORDER BY DATE DESC LIMIT 1');
} elsif ( "range" eq $directive ) {
	# select range starting with lastest as 1
	my $start = $get_params[0];
	my $count = $get_params[1];
	$sth = $db->prepare('SELECT * FROM posts ORDER BY DATE DESC LIMIT '.$start.', '.$count);
} else {
	# select the last 10 posts
	$sth = $db->prepare('SELECT * FROM posts ORDER BY DATE DESC LIMIT 10');
}
$sth->execute or soft_die($sth->errstr);

print http_status(200,"text/json");
print $json->encode( $sth->fetchall_arrayref({}));