<?php
/**
 * Piwik - free/libre analytics platform
 *
 * @link http://piwik.org
 * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
 *
 */
namespace Piwik\Plugins\ImageGraph;

use Piwik\API\Request;
use Piwik\Common;
use Piwik\Config;
use Piwik\Container\StaticContainer;
use Piwik\Period;
use Piwik\Period\Range;
use Piwik\Piwik;
use Piwik\Scheduler\Scheduler;
use Piwik\Site;
use Piwik\Url;
use Piwik\Period\Factory as PeriodFactory;

class ImageGraph extends \Piwik\Plugin
{
    private static $CONSTANT_ROW_COUNT_REPORT_EXCEPTIONS = array(
        'Referrers_getReferrerType',
    );

    // row evolution support not yet implemented for these APIs
    private static $REPORTS_DISABLED_EVOLUTION_GRAPH = array(
        'Referrers_getAll',
    );

    /**
     * @see Piwik\Plugin::registerEvents
     */
    public function registerEvents()
    {
        $hooks = array(
            'API.getReportMetadata.end' => array('function' => 'getReportMetadata',
                                                 'after'    => true),
        );
        return $hooks;
    }

    // Number of periods to plot on an evolution graph
    const GRAPH_EVOLUTION_LAST_PERIODS = 30;

    /**
     * @param array $reports
     * @param array $info
     * @return mixed
     */
    public function getReportMetadata(&$reports, $info)
    {
        $idSite = $info['idSite'];

        // If only one website is selected, we add the Graph URL
        if (empty($idSite)) {
            return;
        }
        
        // in case API.getReportMetadata was not called with date/period we use sane defaults
        if (empty($info['period'])) {
            $info['period'] = 'day';
        }
        if (empty($info['date'])) {
            $info['date'] = 'today';
        }

        // need two sets of period & date, one for single period graphs, one for multiple periods graphs
        if (Period::isMultiplePeriod($info['date'], $info['period'])) {
            $periodForMultiplePeriodGraph = $info['period'];
            $dateForMultiplePeriodGraph = $info['date'];

            $periodForSinglePeriodGraph = 'range';
            $dateForSinglePeriodGraph = $info['date'];
        } else {
            $periodForSinglePeriodGraph = $info['period'];
            $dateForSinglePeriodGraph = $info['date'];

            $piwikSite = new Site($idSite);
            if ($periodForSinglePeriodGraph == 'range') {
                // for period=range, show the configured sub-periods
                $periodForMultiplePeriodGraph = Config::getInstance()->General['graphs_default_period_to_plot_when_period_range'];
                $dateForMultiplePeriodGraph = $dateForSinglePeriodGraph;
            } else if ($info['period'] == 'day' || !Config::getInstance()->General['graphs_show_evolution_within_selected_period']) {
                // for period=day, always show the last n days
                // if graphs_show_evolution_within_selected_period=false, show the last n periods
				$periodForMultiplePeriodGraph = $periodForSinglePeriodGraph;
				$dateForMultiplePeriodGraph = Range::getRelativeToEndDate(
					$periodForSinglePeriodGraph,
					'last' . self::getDefaultGraphEvolutionLastPeriods(),
					$dateForSinglePeriodGraph,
					$piwikSite
				);
			} else {
                // if graphs_show_evolution_within_selected_period=true, show the days within the period
                // (except if the period is day, see above)
				$periodForMultiplePeriodGraph = 'day';
				$period = PeriodFactory::build($info['period'], $info['date']);
				$start = $period->getDateStart()->toString();
				$end = $period->getDateEnd()->toString();
				$dateForMultiplePeriodGraph = $start . ',' . $end;
            }
        }

        $token_auth = Common::getRequestVar('token_auth', false);

        $segment = Request::getRawSegmentFromRequest();

        /** @var Scheduler $scheduler */
        $scheduler = StaticContainer::getContainer()->get('Piwik\Scheduler\Scheduler');
        $isRunningTask = $scheduler->isRunningTask();

        // add the idSubtable if it exists
        $idSubtable = Common::getRequestVar('idSubtable', false);

        $urlPrefix = "index.php?";
        foreach ($reports as &$report) {
            $reportModule = $report['module'];
            $reportAction = $report['action'];
            $reportUniqueId = $reportModule . '_' . $reportAction;

            $parameters = array();
            $parameters['module'] = 'API';
            $parameters['method'] = 'ImageGraph.get';
            $parameters['idSite'] = $idSite;
            $parameters['apiModule'] = $reportModule;
            $parameters['apiAction'] = $reportAction;
            if (!empty($token_auth)) {
                $parameters['token_auth'] = $token_auth;
            }

            // Forward custom Report parameters to the graph URL
            if (!empty($report['parameters'])) {
                $parameters = array_merge($parameters, $report['parameters']);
            }
            if (empty($report['dimension'])) {
                $parameters['period'] = $periodForMultiplePeriodGraph;
                $parameters['date'] = $dateForMultiplePeriodGraph;
            } else {
                $parameters['period'] = $periodForSinglePeriodGraph;
                $parameters['date'] = $dateForSinglePeriodGraph;
            }

            if ($idSubtable !== false) {
                $parameters['idSubtable'] = $idSubtable;
            }

            if (!empty($_GET['_restrictSitesToLogin']) && $isRunningTask) {
                $parameters['_restrictSitesToLogin'] = $_GET['_restrictSitesToLogin'];
            }

            if (!empty($segment)) {
                $parameters['segment'] = $segment;
            }

            $report['imageGraphUrl'] = $urlPrefix . Url::getQueryStringFromParameters($parameters);

            // thanks to API.getRowEvolution, reports with dimensions can now be plotted using an evolution graph
            // however, most reports with a fixed set of dimension values are excluded
            // this is done so Piwik Mobile and Scheduled Reports do not display them
            $reportWithDimensionsSupportsEvolution = empty($report['constantRowsCount']) || in_array($reportUniqueId, self::$CONSTANT_ROW_COUNT_REPORT_EXCEPTIONS);

            $reportSupportsEvolution = !in_array($reportUniqueId, self::$REPORTS_DISABLED_EVOLUTION_GRAPH);

            if ($reportSupportsEvolution
                && $reportWithDimensionsSupportsEvolution
            ) {
                $parameters['period'] = $periodForMultiplePeriodGraph;
                $parameters['date'] = $dateForMultiplePeriodGraph;
                $report['imageGraphEvolutionUrl'] = $urlPrefix . Url::getQueryStringFromParameters($parameters);
            }
        }
    }

    public static function getDefaultGraphEvolutionLastPeriods()
    {
        $lastPeriods = (int) Config::getInstance()->General['graphs_default_evolution_graph_last_days_amount'];
        if ($lastPeriods <= 0) {
            throw new \Exception("Invalid value '$lastPeriods' supplied for [General] graphs_default_evolution_graph_last_days_amount config.");
        }
        return $lastPeriods;
    }
}
