#!/usr/bin/perl
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.
#
# This Source Code Form is "Incompatible With Secondary Licenses", as
# defined by the Mozilla Public License, v. 2.0.

use 5.10.1;
use strict;
use warnings;

use lib qw(. lib);

use Getopt::Long qw(:config bundling);
use Pod::Usage;
use List::Util qw(first);
use Cwd;

use Bugzilla;
use Bugzilla::Constants;
use Bugzilla::Error;
use Bugzilla::Util;
use Bugzilla::Search;
use Bugzilla::User;
use Bugzilla::Product;
use Bugzilla::Field;
use Bugzilla::Install::Filesystem qw(fix_dir_permissions);

my %switch;
GetOptions(\%switch, 'help|h', 'regenerate');

# Print the help message if that switch was selected.
pod2usage({-verbose => 1, -exitval => 1}) if $switch{'help'};

# Turn off output buffering (probably needed when displaying output feedback
# in the regenerate mode).
$| = 1;

my $datadir = bz_locations()->{'datadir'};
my $graphsdir = bz_locations()->{'graphsdir'};

# We use a dummy product instance with ID 0, representing all products
my $product_all = {id => 0, name => '-All-'};
bless($product_all, 'Bugzilla::Product');

# Tidy up after graphing module
my $cwd = Cwd::getcwd();
if (chdir($graphsdir)) {
    unlink <./*.gif>;
    unlink <./*.png>;
    # chdir("..") doesn't work if graphs is a symlink, see bug 429378
    chdir($cwd);
}

my $dbh = Bugzilla->switch_to_shadow_db();

# As we can now customize statuses and resolutions, looking at the current list
# of legal values only is not enough as some now removed statuses and resolutions
# may have existed in the past, or have been renamed. We want them all.
my $fields = {};
foreach my $field ('bug_status', 'resolution') {
    my $values = get_legal_field_values($field);
    my $old_values = $dbh->selectcol_arrayref(
                             "SELECT bugs_activity.added
                                FROM bugs_activity
                          INNER JOIN fielddefs
                                  ON fielddefs.id = bugs_activity.fieldid
                           LEFT JOIN $field
                                  ON $field.value = bugs_activity.added
                               WHERE fielddefs.name = ?
                                 AND $field.id IS NULL

                               UNION

                              SELECT bugs_activity.removed
                                FROM bugs_activity
                          INNER JOIN fielddefs
                                  ON fielddefs.id = bugs_activity.fieldid
                           LEFT JOIN $field
                                  ON $field.value = bugs_activity.removed
                               WHERE fielddefs.name = ?
                                 AND $field.id IS NULL",
                               undef, ($field, $field));

    push(@$values, @$old_values);
    $fields->{$field} = $values;
}

my @statuses = @{$fields->{'bug_status'}};
my @resolutions = @{$fields->{'resolution'}};
# Exclude "" from the resolution list.
@resolutions = grep {$_} @resolutions;

# --regenerate was taking an enormous amount of time to query everything
# per bug, per day. Instead, we now just get all the data out of the DB
# at once and stuff it into some data structures.
my (%bug_status, %bug_resolution, %removed);
if ($switch{'regenerate'}) {
    %bug_resolution = @{ $dbh->selectcol_arrayref(
        'SELECT bug_id, resolution FROM bugs', {Columns=>[1,2]}) };
    %bug_status = @{ $dbh->selectcol_arrayref(
        'SELECT bug_id, bug_status FROM bugs', {Columns=>[1,2]}) };

    my $removed_sth = $dbh->prepare(
        q{SELECT bugs_activity.bug_id, bugs_activity.removed,}
        . $dbh->sql_to_days('bugs_activity.bug_when')
       . q{ FROM bugs_activity
           WHERE bugs_activity.fieldid = ?
        ORDER BY bugs_activity.bug_when});

    %removed = (bug_status => {}, resolution => {});
    foreach my $field (qw(bug_status resolution)) {
        my $field_id = Bugzilla::Field->check($field)->id;
        my $rows = $dbh->selectall_arrayref($removed_sth, undef, $field_id);
        my $hash = $removed{$field};
        foreach my $row (@$rows) {
            my ($bug_id, $removed, $when) = @$row;
            $hash->{$bug_id} ||= [];
            push(@{ $hash->{$bug_id} }, { when    => int($when),
                                          removed => $removed });
        }
    }
}

my $tstart = time;

my @myproducts = Bugzilla::Product->get_all;
unshift(@myproducts, $product_all);

my $dir = "$datadir/mining";
if (!-d $dir) {
    mkdir $dir or die "mkdir $dir failed: $!";
    fix_dir_permissions($dir);
}

foreach (@myproducts) {
    if ($switch{'regenerate'}) {
        regenerate_stats($dir, $_, \%bug_resolution, \%bug_status, \%removed);
    } else {
        &collect_stats($dir, $_);
    }
}
# Fix permissions for all files in mining/.
fix_dir_permissions($dir);

my $tend = time;
# Uncomment the following line for performance testing.
#say "Total time taken " . delta_time($tstart, $tend);

CollectSeriesData();

sub collect_stats {
    my $dir = shift;
    my $product = shift;
    my $when = localtime (time);
    my $dbh = Bugzilla->dbh;

    my $file = join '/', $dir, $product->id;
    my $exists = -f $file;

    # if the file exists, get the old status and resolution list for that product.
    my @data;
    @data = get_old_data($file) if $exists;

    # If @data is not empty, then we have to recreate the data file.
    if (scalar(@data)) {
        open(DATA, '>', $file)
          || ThrowCodeError('chart_file_open_fail', {'filename' => $file});
    }
    else {
        open(DATA, '>>', $file)
          || ThrowCodeError('chart_file_open_fail', {'filename' => $file});
    }

    if (Bugzilla->params->{'utf8'}) {
        binmode DATA, ':utf8';
    }

    # Now collect current data.
    my @row = (today());
    my $status_sql = q{SELECT COUNT(*) FROM bugs WHERE bug_status = ?};
    my $reso_sql   = q{SELECT COUNT(*) FROM bugs WHERE resolution = ?};

    if ($product->id) {
        $status_sql .= q{ AND product_id = ?};
        $reso_sql   .= q{ AND product_id = ?};
    }

    my $sth_status = $dbh->prepare($status_sql);
    my $sth_reso   = $dbh->prepare($reso_sql);

    my @values ;
    foreach my $status (@statuses) {
        @values = ($status);
        push (@values, $product->id) if ($product->id);
        my $count = $dbh->selectrow_array($sth_status, undef, @values);
        push(@row, $count);
    }
    foreach my $resolution (@resolutions) {
        @values = ($resolution);
        push (@values, $product->id) if ($product->id);
        my $count = $dbh->selectrow_array($sth_reso, undef, @values);
        push(@row, $count);
    }

    if (!$exists || scalar(@data)) {
        my $fields = join('|', ('DATE', @statuses, @resolutions));
        my $product_name = $product->name;
        print DATA <<FIN;
# Bugzilla Daily Bug Stats
#
# Do not edit me! This file is generated.
#
# fields: $fields
# Product: $product_name
# Created: $when
FIN
    }

    # Add existing data, if needed. Note that no count is not treated
    # the same way as a count with 0 bug.
    foreach my $data (@data) {
        print DATA join('|', map {defined $data->{$_} ? $data->{$_} : ''}
                                 ('DATE', @statuses, @resolutions)) . "\n";
    }
    print DATA (join '|', @row) . "\n";
    close DATA;
}

sub get_old_data {
    my $file = shift;

    open(DATA, '<', $file)
      || ThrowCodeError('chart_file_open_fail', {'filename' => $file});

    if (Bugzilla->params->{'utf8'}) {
        binmode DATA, ':utf8';
    }

    my @data;
    my @columns;
    my $recreate = 0;
    while (<DATA>) {
        chomp;
        next unless $_;
        if (/^# fields?:\s*(.+)\s*$/) {
            @columns = split(/\|/, $1);
            # Compare this list with @statuses and @resolutions.
            # If they are identical, then we can safely append new data
            # to the end of the file; else we have to recreate it.
            $recreate = 1;
            my @new_cols = ($columns[0], @statuses, @resolutions);
            if (scalar(@columns) == scalar(@new_cols)) {
                my $identical = 1;
                for (0 .. $#columns) {
                    $identical = 0 if ($columns[$_] ne $new_cols[$_]);
                }
                last if $identical;
            }
        }
        next unless $recreate;
        next if (/^#/); # Ignore comments.
        # If we have to recreate the file, we have to load all existing
        # data first.
        my @line = split /\|/;
        my %data;
        foreach my $column (@columns) {
            $data{$column} = shift @line;
        }
        push(@data, \%data);
    }
    close(DATA);
    return @data;
}

# This regenerates all statistics from the database.
sub regenerate_stats {
    my ($dir, $product, $bug_resolution, $bug_status, $removed) = @_;

    my $dbh = Bugzilla->dbh;
    my $when = localtime(time());
    my $tstart = time();

    my $file = join '/', $dir, $product->id;

    my $and_product = "";

    my @values = ();
    if ($product->id) {
        $and_product = q{ AND product_id = ?};
        push (@values, $product->id);
    }

    # Determine the start date from the date the first bug in the
    # database was created, and the end date from the current day.
    # If there were no bugs in the search, return early.
    my $query = q{SELECT } .
                $dbh->sql_to_days('creation_ts') . q{ AS start_day, } .
                $dbh->sql_to_days('current_date') . q{ AS end_day, } . 
                $dbh->sql_to_days("'1970-01-01'") . 
                 qq{ FROM bugs
                   WHERE } . $dbh->sql_to_days('creation_ts') . 
                         qq{ IS NOT NULL $and_product 
                ORDER BY start_day } . $dbh->sql_limit(1);
    my ($start, $end, $base) = $dbh->selectrow_array($query, undef, @values);

    if (!defined $start) {
        return;
    }

    if (open DATA, ">", $file) {
        my $fields = join('|', ('DATE', @statuses, @resolutions));
        my $product_name = $product->name;
        print DATA <<FIN;
# Bugzilla Daily Bug Stats
#
# Do not edit me! This file is generated.
#
# fields: $fields
# Product: $product_name
# Created: $when
FIN
        # For each day, generate a line of statistics.
        my $total_days = $end - $start;
        my @bugs;
        for (my $day = $start + 1; $day <= $end; $day++) {
            # Some output feedback
            my $percent_done = ($day - $start - 1) * 100 / $total_days;
            printf "\rRegenerating %s \[\%.1f\%\%]", $product_name,
                                                     $percent_done;

            # Get a list of bugs that were created the previous day, and
            # add those bugs to the list of bugs for this product.
            $query = qq{SELECT bug_id 
                          FROM bugs
                         WHERE bugs.creation_ts < } . 
                         $dbh->sql_from_days($day - 1) . 
                         q{ AND bugs.creation_ts >= } . 
                         $dbh->sql_from_days($day - 2) . 
                        $and_product . q{ ORDER BY bug_id};

            my $bug_ids = $dbh->selectcol_arrayref($query, undef, @values);
            push(@bugs, @$bug_ids);

            my %bugcount;
            foreach (@statuses) { $bugcount{$_} = 0; }
            foreach (@resolutions) { $bugcount{$_} = 0; }
            # Get information on bug states and resolutions.
            for my $bug (@bugs) {
                my $status = _get_value(
                    $removed->{'bug_status'}->{$bug},
                    $bug_status,  $day, $bug);

                if (defined $bugcount{$status}) {
                    $bugcount{$status}++;
                }

                my $resolution = _get_value(
                    $removed->{'resolution'}->{$bug},
                    $bug_resolution, $day, $bug);

                if (defined $bugcount{$resolution}) {
                    $bugcount{$resolution}++;
                }
            }

            # Generate a line of output containing the date and counts
            # of bugs in each state.
            my $date = sqlday($day, $base);
            print DATA "$date";
            foreach (@statuses) { print DATA "|$bugcount{$_}"; }
            foreach (@resolutions) { print DATA "|$bugcount{$_}"; }
            print DATA "\n";
        }

        # Finish up output feedback for this product.
        my $tend = time;
        say "\rRegenerating " . $product_name . ' [100.0%] - ' .
            delta_time($tstart, $tend);

        close DATA;
    }
}

# A helper for --regenerate.
# For each bug that exists on a day, we determine its status/resolution
# at the beginning of the day.  If there were no status/resolution
# changes on or after that day, the status was the same as it
# is today (the "current" value).  Otherwise, the status was equal to the
# first "previous value" entry in the bugs_activity table for that 
# bug made on or after that day.
sub _get_value {
    my ($removed, $current, $day, $bug) = @_;

    # Get the first change that's on or after this day.
    my $item = first { $_->{when} >= $day } @{ $removed || [] };

    # If there's no change on or after this day, then we just return the
    # current value.
    return $item ? $item->{removed} : $current->{$bug};
}

sub today {
    my ($dom, $mon, $year) = (localtime(time))[3, 4, 5];
    return sprintf "%04d%02d%02d", 1900 + $year, ++$mon, $dom;
}

sub today_dash {
    my ($dom, $mon, $year) = (localtime(time))[3, 4, 5];
    return sprintf "%04d-%02d-%02d", 1900 + $year, ++$mon, $dom;
}

sub sqlday {
    my ($day, $base) = @_;
    $day = ($day - $base) * 86400;
    my ($dom, $mon, $year) = (gmtime($day))[3, 4, 5];
    return sprintf "%04d%02d%02d", 1900 + $year, ++$mon, $dom;
}

sub delta_time {
    my $tstart = shift;
    my $tend = shift;
    my $delta = $tend - $tstart;
    my $hours = int($delta/3600);
    my $minutes = int($delta/60) - ($hours * 60);
    my $seconds = $delta - ($minutes * 60) - ($hours * 3600);
    return sprintf("%02d:%02d:%02d" , $hours, $minutes, $seconds);
}

sub CollectSeriesData {
    # We need some way of randomising the distribution of series, such that
    # all of the series which are to be run every 7 days don't run on the same
    # day. This is because this might put the server under severe load if a
    # particular frequency, such as once a week, is very common. We achieve
    # this by only running queries when:
    # (days_since_epoch + series_id) % frequency = 0. So they'll run every
    # <frequency> days, but the start date depends on the series_id.
    my $days_since_epoch = int(time() / (60 * 60 * 24));
    my $today = today_dash();

    # We save a copy of the main $dbh and then switch to the shadow and get
    # that one too. Remember, these may be the same.
    my $dbh = Bugzilla->switch_to_main_db();
    my $shadow_dbh = Bugzilla->switch_to_shadow_db();
    
    my $serieses = $dbh->selectall_hashref("SELECT series_id, query, creator " .
                      "FROM series " .
                      "WHERE frequency != 0 AND " . 
                      "MOD(($days_since_epoch + series_id), frequency) = 0",
                      "series_id");

    # We prepare the insertion into the data table, for efficiency.
    my $sth = $dbh->prepare("INSERT INTO series_data " .
                            "(series_id, series_date, series_value) " .
                            "VALUES (?, " . $dbh->quote($today) . ", ?)");

    # We delete from the table beforehand, to avoid SQL errors if people run
    # collectstats.pl twice on the same day.
    my $deletesth = $dbh->prepare("DELETE FROM series_data 
                                   WHERE series_id = ? AND series_date = " .
                                   $dbh->quote($today));
                                     
    foreach my $series_id (keys %$serieses) {
        # We set up the user for Search.pm's permission checking - each series
        # runs with the permissions of its creator.
        my $user = new Bugzilla::User($serieses->{$series_id}->{'creator'});
        my $cgi = new Bugzilla::CGI($serieses->{$series_id}->{'query'});
        my $data;

        # Do not die if Search->new() detects invalid data, such as an obsolete
        # login name or a renamed product or component, etc.
        eval {
            my $search = new Bugzilla::Search('params' => scalar $cgi->Vars,
                                              'fields' => ["bug_id"],
                                              'allow_unlimited' => 1,
                                              'user'   => $user);
            $data = $search->data;
        };

        if (!$@) {
            # We need to count the returned rows. Without subselects, we can't
            # do this directly in the SQL for all queries. So we do it by hand.
            my $count = scalar(@$data) || 0;

            $deletesth->execute($series_id);
            $sth->execute($series_id, $count);
        }
    }
}

__END__

=head1 NAME

collectstats.pl - Collect data about Bugzilla bugs.

=head1 SYNOPSIS

 ./collectstats.pl [--regenerate] [--help]

Collects data about bugs to be used in Old and New Charts.

=head1 OPTIONS

=over

=item B<--help>

Print this help page.

=item B<--regenerate>

Recreate all the data about bugs, from day 1. This option is only relevant
for Old Charts, and has no effect for New Charts.
This option will overwrite all existing collected data and can take a huge
amount of time. You normally don't need to use this option (do not use it
in a cron job).

=back

=head1 DESCRIPTION

This script collects data about all bugs for Old Charts, triaged by product
and by bug status and resolution. It also collects data for New Charts, based
on existing series. For New Charts, data is only collected once a series is
defined; this script cannot recreate data prior to this date.