#!/usr/bin/perl
# Copyright (C) 2014 Laurentian University
# Author: Dan Scott <dscott@laurentian.ca>
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

use strict; use warnings;
use XML::LibXML;
use File::Copy;
use Getopt::Long;
use File::Spec;
use File::Basename;
use DBI qw(:sql_types);
use DBD::Pg qw(:pg_types);

my ($dbhost, $dbport, $dbname, $dbuser, $dbpw, $help);
my $config_file = '';
my $sysconfdir = '';

=item create_sitemaps() - Write the sitemap files

With a maximum of 50,000 URLs per sitemap, this method
automatically increments the sitemap file numbers and
generates a corresponding sitemap index that lists all
of the individual sitemap files.

See http://www.sitemaps.org/ for the specification

=cut
sub create_sitemaps {
    my ($settings, $bibs, $aou_id) = @_;

    my $f_cnt = 1;
    my $r_cnt = 0;
    my @sitemaps;
    my $fn = $settings->{'prefix'} . "sitemap$f_cnt.xml";
    push(@sitemaps, $fn);
    open(FH, '>', $fn) or die "Could not write sitemap $f_cnt\n";
    print FH '<?xml version="1.0" encoding="UTF-8"?>' . "\n";
    print FH '<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">' . "\n";

    foreach my $bib (@$bibs) {
        print FH "<url><loc>" . $settings->{'lib-hostname'} . "/eg/opac/record/" . $bib->[0];
        if ($aou_id) {
            print FH "?locg=$aou_id";
        }
        print FH "</loc><lastmod>" . $bib->[1] . "</lastmod></url>\n";
        $r_cnt++;
        if ($r_cnt % 50000 == 0) {
            $f_cnt++;
            print FH "</urlset>\n";
            close(FH);
            my $fn = $settings->{'prefix'} . "sitemap$f_cnt.xml";
            push(@sitemaps, $fn);
            open(FH, '>', $fn) or die "Could not write bibs\n";
            print FH '<?xml version="1.0" encoding="UTF-8"?>' . "\n";
            print FH '<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">' . "\n";
        }
    }
    print FH "</urlset>\n";
    close(FH);

    open(INDEXFH, '>', $settings->{'prefix'} . "sitemapindex.xml") or die "Could not write sitemap index\n";
    print INDEXFH '<?xml version="1.0" encoding="UTF-8"?>' . "\n";
    print INDEXFH '<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">' . "\n";
    foreach my $fn (@sitemaps) {
        print INDEXFH "<sitemap><loc>" . $settings->{'lib-hostname'} . "/$fn</loc></sitemap>\n";
    }
    print INDEXFH "</sitemapindex>\n";
    close(INDEXFH);
    

}

=item get_settings() - Extracts database settings from opensrf.xml
=cut
sub get_settings {
    my $settings = shift;

    my $host = "/opensrf/default/apps/open-ils.reporter-store/app_settings/database/host/text()";
    my $port = "/opensrf/default/apps/open-ils.reporter-store/app_settings/database/port/text()";
    my $dbname = "/opensrf/default/apps/open-ils.reporter-store/app_settings/database/db/text()";
    my $user = "/opensrf/default/apps/open-ils.reporter-store/app_settings/database/user/text()";
    my $pw = "/opensrf/default/apps/open-ils.reporter-store/app_settings/database/pw/text()";

    my $parser = XML::LibXML->new();
    my $opensrf_config = $parser->parse_file($config_file);

    # If the user passed in settings at the command line,
    # we don't want to override them
    $settings->{host} = $settings->{host} || $opensrf_config->findnodes($host);
    $settings->{port} = $settings->{port} || $opensrf_config->findnodes($port);
    $settings->{db} = $settings->{db} || $opensrf_config->findnodes($dbname);
    $settings->{user} = $settings->{user} || $opensrf_config->findnodes($user);
    $settings->{pw} = $settings->{pw} || $opensrf_config->findnodes($pw);
}

=item get_record_ids() - Gets a list of record IDs
=cut
sub get_record_ids {
    my $settings = shift;
    my $aou_id;

    my $dbh = DBI->connect('dbi:Pg:dbname=' . $settings->{db} . 
        ';host=' . $settings->{host} . ';port=' . $settings->{port} . ';',
         $settings->{user} . "", $settings->{pw} . "", {AutoCommit => 1}
    );
    if ($dbh->err) {
        print STDERR "Could not connect to database. ";
        print STDERR "Error was " . $dbh->errstr . "\n";
        return;
    }

    if ($settings->{'lib-shortname'}) {
        my $stmt = $dbh->prepare("SELECT id FROM actor.org_unit WHERE shortname = ?");
        $stmt->execute(($settings->{'lib-shortname'}));
        my $rv = $stmt->bind_columns(\$aou_id);
        $stmt->fetch();
    }

    my $q = "
        WITH date_floor AS (
            SELECT ?::date AS val
        )
    ";
    if ($aou_id) {
        $q .= "
        , copy_orgs AS (
            SELECT id
            FROM actor.org_unit
            WHERE id IN (SELECT id FROM actor.org_unit_descendants(?))
        ),
        uri_orgs AS (
            SELECT id
            FROM actor.org_unit
            WHERE id IN (SELECT id FROM actor.org_unit_ancestors(?))
                AND id NOT IN (SELECT id FROM org_top())
        )
        ";
    }
    $q .= "
        SELECT DISTINCT id, edit_date FROM (
            SELECT bre.id,
                CASE
                    WHEN bre.edit_date::date < (SELECT val FROM date_floor LIMIT 1) THEN (SELECT val FROM date_floor LIMIT 1)
                    ELSE bre.edit_date::date
                END AS edit_date
            FROM biblio.record_entry bre
                INNER JOIN asset.opac_visible_copies aovc ON bre.id = aovc.record
    ";
    if ($aou_id) {
        $q .= " WHERE circ_lib IN (SELECT id FROM copy_orgs)";
    }
    $q .= "
            UNION 
            SELECT bre.id,
                CASE
                    WHEN bre.edit_date::date < (SELECT val FROM date_floor LIMIT 1) THEN (SELECT val FROM date_floor LIMIT 1)
                    ELSE bre.edit_date::date
                END AS edit_date
            FROM biblio.record_entry bre
                INNER JOIN asset.call_number acn ON bre.id = acn.record
            WHERE bre.deleted IS FALSE AND acn.deleted IS FALSE 
    ";
    if ($aou_id) {
        $q .= "
            AND owning_lib IN (SELECT id FROM uri_orgs) AND label = '##URI##'
        ";
    }
    $q .= "
        ) x
        ORDER BY edit_date DESC, id DESC
    ";
    my $stmt = $dbh->prepare($q);
    if ($aou_id) {
        $stmt->bind_param(1, $settings->{'date'}, { pg_type => PG_DATE });
        $stmt->bind_param(2, $aou_id, SQL_INTEGER);
        $stmt->bind_param(3, $aou_id, SQL_INTEGER);
    } else {
        $stmt->bind_param(1, $settings->{'date'}, { pg_type => PG_DATE });
    }
    $stmt->execute();

    my $bibs = $stmt->fetchall_arrayref([0, 1]);

    if ($dbh->err) {
        print STDERR "Error was " . $dbh->errstr . "\n";
        return;
    }
    return ($bibs, $aou_id);
}

my $hostname;
my $aou_shortname;
my %settings = (
    prefix => '',
    date => '2010-01-01'
);

GetOptions(
        "lib-hostname=s" => \$settings{'lib-hostname'},
        "lib-shortname=s" => \$settings{'lib-shortname'},
        "prefix=s" => \$settings{'prefix'},
        "date-floor=s" => \$settings{'date'},
        "config-file=s" => \$config_file,
        "user=s" => \$settings{'user'},
        "password=s" => \$settings{'pw'},
        "database=s" => \$settings{'db'},
        "hostname=s" => \$settings{'host'},
        "port=i" => \$settings{'port'}, 
        "help" => \$help
);

if (!$config_file) { 
    my @temp = `eg_config --sysconfdir`;
    chomp $temp[0];
    $sysconfdir = $temp[0];
    $config_file = File::Spec->catfile($sysconfdir, "opensrf.xml");
}

unless (-e $config_file) { die "Error: $config_file does not exist. \n"; }

if ($settings{'lib-hostname'}) {
    # Get additional settings from the config file
    get_settings(\%settings);

    my ($bibs, $aou_id) = get_record_ids(\%settings);
    create_sitemaps(\%settings, $bibs, $aou_id);
} else {
    $help = 1;
}

if ($help) {
    print <<HERE;

SYNOPSIS
    sitemap_generator [OPTION] ... [COMMAND] ... [CONFIG OPTIONS]

DESCRIPTION
    Creates a set of sitemaps for enabling web crawlers to crawl
    freshly changed bibliographic records.

OPTIONS
    --config-file
        specifies the opensrf.xml file

    --lib-hostname
        REQUIRED: hostname for the catalog (e.g "https://example.com")

    --prefix
        filename to add as a prefix to the generated set of sitemap files

    --date-floor
        a date in YYYY-MM-DD format that specifies the minimum date that
        should be reflected for when a record was last updated; useful if
        you enrich or change the HTML without changing records. Defaults
        to 2010-01-01

    --lib-shortname
        include all records for the specified library and its children;
        defaults to all records

EXAMPLES
   This script will normally be run as a cron job by the opensrf user from
   the web root directory.

   sitemap_generator --lib-hostname https://example.com --lib-shortname BR1 \
      --prefix example_

   This generates a set of sitemap files like so:
     * example_sitemapindex.xml
     * example_sitemap1.xml
     * example_sitemap2.xml
     * ...

HERE
}