#!/usr/bin/perl -T
# 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 Bugzilla;
use Bugzilla::Constants;
use Bugzilla::Util;
use Bugzilla::Error;
use Bugzilla::Status;

use File::Basename;
use Digest::SHA qw(hmac_sha256_base64);

# If we're using bug groups for products, we should apply those restrictions
# to viewing reports, as well.  Time to check the login in that case.
my $user     = Bugzilla->login();
my $cgi      = Bugzilla->cgi;
my $template = Bugzilla->template;
my $vars     = {};

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

if (!Bugzilla->feature('old_charts')) {
  ThrowUserError('feature_disabled', {feature => 'old_charts'});
}

my $dir        = bz_locations()->{'datadir'} . "/mining";
my $graph_dir  = bz_locations()->{'graphsdir'};
my $graph_url  = basename($graph_dir);
my $product_id = $cgi->param('product_id');

Bugzilla->switch_to_shadow_db();

if (!defined($product_id)) {

  # Can we do bug charts?
  (-d $dir && -d $graph_dir)
    || ThrowCodeError('chart_dir_nonexistent',
    {dir => $dir, graph_dir => $graph_dir});

  my %default_sel = map { $_ => 1 } BUG_STATE_OPEN;

  my @datasets;
  my @data = get_data($dir);

  foreach my $dataset (@data) {
    my $datasets = {};
    $datasets->{'value'}    = $dataset;
    $datasets->{'selected'} = $default_sel{$dataset} ? 1 : 0;
    push(@datasets, $datasets);
  }

  $vars->{'datasets'} = \@datasets;

  print $cgi->header();
}
else {
  my $product;

  # For security and correctness, validate the value of the "product_id" form
  # variable. Valid values are IDs of those products for which the user has
  # permissions which appear in the "product_id" drop-down menu on the report
  # generation form. The product_id 0 is a special case, meaning "All
  # Products".
  if ($product_id) {
    $product = Bugzilla::Product->new($product_id);
    $product && $user->can_see_product($product->name)
      || ThrowUserError('product_access_denied', {id => $product_id});
  }
  else {
    $product = $product_all;
  }

  # Make sure there is something to plot.
  my @datasets = $cgi->param('datasets');
  scalar(@datasets) || ThrowUserError('missing_datasets');

  if (grep { $_ !~ /^[A-Za-z0-9:_-]+$/ } @datasets) {
    ThrowUserError('invalid_datasets', {'datasets' => \@datasets});
  }

  # Filenames must not be guessable as they can point to products
  # you are not allowed to see. Also, different projects can have
  # the same product IDs.
  my $project    = bz_locations()->{'project'} || '';
  my $image_file = join(':', ($project, $product->id, @datasets));
  my $key        = Bugzilla->localconfig->{'site_wide_secret'};
  $image_file = hmac_sha256_base64($image_file, $key) . '.png';
  $image_file =~ s/\+/-/g;
  $image_file =~ s/\//_/g;
  trick_taint($image_file);

  if (!-e "$graph_dir/$image_file") {
    generate_chart($dir, "$graph_dir/$image_file", $product, \@datasets);
  }

  $vars->{'url_image'} = "$graph_url/$image_file";

  print $cgi->header(
    -Content_Disposition => 'inline; filename=bugzilla_report.html');
}

$template->process('reports/old-charts.html.tmpl', $vars)
  || ThrowTemplateError($template->error());

#####################
#    Subroutines    #
#####################

sub get_data {
  my $dir = shift;

  my @datasets;
  open(DATA, '<', "$dir/0")
    || ThrowCodeError('chart_file_open_fail', {filename => "$dir/0"});

  while (<DATA>) {
    if (/^# fields?: (.+)\s*$/) {
      @datasets = grep !/date/i, (split /\|/, $1);
      last;
    }
  }
  close(DATA);
  return @datasets;
}

sub generate_chart {
  my ($dir, $image_file, $product, $datasets) = @_;
  my $data_file = $dir . '/' . $product->id;

  if (!open(FILE, '<', $data_file)) {
    ThrowCodeError('chart_data_not_generated', {'product' => $product});
  }

  my $product_in_title = $product->id ? $product->name : 'All Products';
  my @fields;
  my @labels   = qw(DATE);
  my %datasets = map { $_ => 1 } @$datasets;

  my %data = ();
  while (<FILE>) {
    chomp;
    next unless $_;
    if (/^#/) {
      if (/^# fields?: (.*)\s*$/) {
        @fields = split /\||\r/, $1;
        $data{$_} ||= [] foreach @fields;
        unless ($fields[0] =~ /date/i) {
          ThrowCodeError('chart_datafile_corrupt', {'file' => $data_file});
        }
        push @labels, grep($datasets{$_}, @fields);
      }
      next;
    }

    unless (@fields) {
      ThrowCodeError('chart_datafile_corrupt', {'file' => $data_file});
    }

    my @line = split /\|/;
    my $date = $line[0];
    my ($yy, $mm, $dd) = $date =~ /^\d{2}(\d{2})(\d{2})(\d{2})$/;
    push @{$data{DATE}}, "$mm/$dd/$yy";

    for my $i (1 .. $#fields) {
      my $field = $fields[$i];
      if (!defined $line[$i] or $line[$i] eq '') {

        # no data point given, don't plot (this will probably
        # generate loads of Chart::Base warnings, but that's not
        # our fault.)
        push @{$data{$field}}, undef;
      }
      else {
        push @{$data{$field}}, $line[$i];
      }
    }
  }

  shift @labels;

  close FILE;

  if (!@{$data{DATE}}) {
    ThrowUserError('insufficient_data_points');
  }

  my $img = Chart::Lines->new(800, 600);
  my $i   = 0;

  my $MAXTICKS = 20;    # Try not to show any more x ticks than this.
  my $skip     = 1;
  if (@{$data{DATE}} > $MAXTICKS) {
    $skip = int((@{$data{DATE}} + $MAXTICKS - 1) / $MAXTICKS);
  }

  my %settings = (
    "title"           => "Status Counts for $product_in_title",
    "x_label"         => "Dates",
    "y_label"         => "Bug Counts",
    "legend_labels"   => \@labels,
    "skip_x_ticks"    => $skip,
    "y_grid_lines"    => "true",
    "grey_background" => "false",
    "colors"          => {

      # default dataset colours are too alike
      dataset4 => [0, 0, 0],    # black
    },
  );

  $img->set(%settings);
  $img->png($image_file, [@data{('DATE', @labels)}]);
}
