<?php
/**
 * Piwik - Open source web analytics
 *
 * @link http://piwik.org
 * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
 *
 */
namespace Piwik\Plugin;

use Exception;
use Piwik\Access;
use Piwik\API\Proxy;
use Piwik\API\Request;
use Piwik\Common;
use Piwik\Config as PiwikConfig;
use Piwik\DataTable\Filter\CalculateEvolutionFilter;
use Piwik\Date;
use Piwik\FrontController;
use Piwik\Menu\MenuTop;
use Piwik\NoAccessException;
use Piwik\Notification\Manager as NotificationManager;
use Piwik\Period\Month;
use Piwik\Period;
use Piwik\Period\Range;
use Piwik\Piwik;
use Piwik\Plugins\CoreAdminHome\CustomLogo;
use Piwik\Plugins\LanguagesManager\LanguagesManager;
use Piwik\Plugins\SitesManager\API as APISitesManager;
use Piwik\Plugins\UsersManager\API as APIUsersManager;
use Piwik\Registry;
use Piwik\SettingsPiwik;
use Piwik\Site;
use Piwik\Url;
use Piwik\View;
use Piwik\View\ViewInterface;
use Piwik\ViewDataTable\Factory as ViewDataTableFactory;

/**
 * Base class of all plugin Controllers.
 * 
 * Plugins that wish to add display HTML should create a Controller that either
 * extends from this class or from {@link ControllerAdmin}. Every public method in
 * the controller will be exposed as a controller method and can be invoked via
 * an HTTP request.
 * 
 * Learn more about Piwik's MVC system [here](/guides/mvc-in-piwik).
 * 
 * ### Examples
 * 
 * **Defining a controller**
 * 
 *     class Controller extends \Piwik\Plugin\Controller
 *     {
 *         public function index()
 *         {
 *             $view = new View("@MyPlugin/index.twig");
 *             // ... setup view ...
 *             return $view->render();
 *         }
 *     }
 * 
 * **Linking to a controller action**
 *
 *     <a href="?module=MyPlugin&action=index&idSite=1&period=day&date=2013-10-10">Link</a>
 * 
 */
abstract class Controller
{
    /**
     * The plugin name, eg. `'Referrers'`.
     * 
     * @var string
     * @api
     */
    protected $pluginName;

    /**
     * The value of the **date** query parameter.
     *
     * @var string
     * @api
     */
    protected $strDate;

    /**
     * The Date object created with ($strDate)[#strDate] or null if the requested date is a range.
     *
     * @var Date|null
     * @api
     */
    protected $date;

    /**
     * The value of the **idSite** query parameter.
     * 
     * @var int
     * @api
     */
    protected $idSite;

    /**
     * The Site object created with {@link $idSite}.
     * 
     * @var Site
     * @api
     */
    protected $site = null;

    /**
     * Constructor.
     * 
     * @api
     */
    public function __construct()
    {
        $this->init();
    }

    protected function init()
    {
        $aPluginName = explode('\\', get_class($this));
        $this->pluginName = $aPluginName[2];

        $date = Common::getRequestVar('date', 'yesterday', 'string');
        try {
            $this->idSite = Common::getRequestVar('idSite', false, 'int');
            $this->site = new Site($this->idSite);
            $date = $this->getDateParameterInTimezone($date, $this->site->getTimezone());
            $this->setDate($date);
        } catch (Exception $e) {
            // the date looks like YYYY-MM-DD,YYYY-MM-DD or other format
            $this->date = null;
        }
    }

    /**
     * Helper method that converts `"today"` or `"yesterday"` to the specified timezone.
     * If the date is absolute, ie. YYYY-MM-DD, it will not be converted to the timezone.
     *
     * @param string $date `'today'`, `'yesterday'`, `'YYYY-MM-DD'`
     * @param string $timezone The timezone to use.
     * @return Date
     * @api
     */
    protected function getDateParameterInTimezone($date, $timezone)
    {
        $timezoneToUse = null;
        // if the requested date is not YYYY-MM-DD, we need to ensure
        //  it is relative to the website's timezone
        if (in_array($date, array('today', 'yesterday'))) {
            // today is at midnight; we really want to get the time now, so that
            // * if the website is UTC+12 and it is 5PM now in UTC, the calendar will allow to select the UTC "tomorrow"
            // * if the website is UTC-12 and it is 5AM now in UTC, the calendar will allow to select the UTC "yesterday"
            if ($date == 'today') {
                $date = 'now';
            } elseif ($date == 'yesterday') {
                $date = 'yesterdaySameTime';
            }
            $timezoneToUse = $timezone;
        }
        return Date::factory($date, $timezoneToUse);
    }

    /**
     * Sets the date to be used by all other methods in the controller.
     * If the date has to be modified, this method should be called just after
     * construction.
     *
     * @param Date $date The new Date.
     * @return void
     * @api
     */
    protected function setDate(Date $date)
    {
        $this->date = $date;
        $this->strDate = $date->toString();
    }

    /**
     * Returns the name of the default method that will be called
     * when visiting: index.php?module=PluginName without the action parameter.
     *
     * @return string
     * @api
     */
    public function getDefaultAction()
    {
        return 'index';
    }

    /**
     * A helper method that renders a view either to the screen or to a string.
     *
     * @param ViewInterface $view The view to render.
     * @return string|void
     */
    protected function renderView(ViewInterface $view)
    {
        return $view->render();
    }

    /**
     * Convenience method that creates and renders a ViewDataTable for a API method.
     *
     * @param string $pluginName The name of the plugin (eg, `'UserSettings'`).
     * @param string $apiAction The name of the API action (eg, `'getResolution'`).
     * @param bool $fetch If `true`, the rendered string is returned, if `false` it is `echo`'d.
     * @throws \Exception if `$pluginName` is not an existing plugin or if `$apiAction` is not an
     *                    existing method of the plugin's API.
     * @return string|void See `$fetch`.
     * @api
     */
    protected function renderReport($apiAction)
    {
        $pluginName = $this->pluginName;

        /** @var Proxy $apiProxy */
        $apiProxy = Proxy::getInstance();

        if (!$apiProxy->isExistingApiAction($pluginName, $apiAction)) {
            throw new \Exception("Invalid action name '$apiAction' for '$pluginName' plugin.");
        }

        $apiAction = $apiProxy->buildApiActionName($pluginName, $apiAction);

        $view      = ViewDataTableFactory::build(null, $apiAction);
        $rendered  = $view->render();

        return $rendered;
    }

    /**
     * Returns a ViewDataTable object that will render a jqPlot evolution graph
     * for the last30 days/weeks/etc. of the current period, relative to the current date.
     *
     * @param string $currentModuleName The name of the current plugin.
     * @param string $currentControllerAction The name of the action that renders the desired
     *                                        report.
     * @param string $apiMethod The API method that the ViewDataTable will use to get
     *                          graph data.
     * @return ViewDataTable
     * @api
     */
    protected function getLastUnitGraph($currentModuleName, $currentControllerAction, $apiMethod)
    {
        $view = ViewDataTableFactory::build(
            'graphEvolution', $apiMethod, $currentModuleName . '.' . $currentControllerAction, $forceDefault = true);
        $view->config->show_goals = false;
        return $view;
    }

    /**
     * Same as {@link getLastUnitGraph()}, but will set some properties of the ViewDataTable
     * object based on the arguments supplied.
     *
     * @param string $currentModuleName The name of the current plugin.
     * @param string $currentControllerAction The name of the action that renders the desired
     *                                        report.
     * @param array $columnsToDisplay The value to use for the ViewDataTable's columns_to_display config
     *                                property.
     * @param array $selectableColumns The value to use for the ViewDataTable's selectable_columns config
     *                                 property.
     * @param bool|string $reportDocumentation The value to use for the ViewDataTable's documentation config
     *                                         property.
     * @param string $apiMethod The API method that the ViewDataTable will use to get graph data.
     * @return ViewDataTable
     * @api
     */
    protected function getLastUnitGraphAcrossPlugins($currentModuleName, $currentControllerAction, $columnsToDisplay = false,
                                                     $selectableColumns = array(), $reportDocumentation = false,
                                                     $apiMethod = 'API.get')
    {
        // load translations from meta data
        $idSite = Common::getRequestVar('idSite');
        $period = Common::getRequestVar('period');
        $date = Common::getRequestVar('date');
        $meta = \Piwik\Plugins\API\API::getInstance()->getReportMetadata($idSite, $period, $date);

        $columns = array_merge($columnsToDisplay, $selectableColumns);
        $translations = array_combine($columns, $columns);
        foreach ($meta as $reportMeta) {
            if ($reportMeta['action'] == 'get' && !isset($reportMeta['parameters'])) {
                foreach ($columns as $column) {
                    if (isset($reportMeta['metrics'][$column])) {
                        $translations[$column] = $reportMeta['metrics'][$column];
                    }
                }
            }
        }

        // initialize the graph and load the data
        $view = $this->getLastUnitGraph($currentModuleName, $currentControllerAction, $apiMethod);
        if ($columnsToDisplay !== false) {
            $view->config->columns_to_display = $columnsToDisplay;
        }

        if (property_exists($view->config, 'selectable_columns')) {
            $view->config->selectable_columns = array_merge($view->config->selectable_columns ? : array(), $selectableColumns);
        }

        $view->config->translations += $translations;

        if ($reportDocumentation) {
            $view->config->documentation = $reportDocumentation;
        }

        return $view;
    }

    /**
     * Returns the array of new processed parameters once the parameters are applied.
     * For example: if you set range=last30 and date=2008-03-10,
     *  the date element of the returned array will be "2008-02-10,2008-03-10"
     *
     * Parameters you can set:
     * - range: last30, previous10, etc.
     * - date: YYYY-MM-DD, today, yesterday
     * - period: day, week, month, year
     *
     * @param array $paramsToSet array( 'date' => 'last50', 'viewDataTable' =>'sparkline' )
     * @throws \Piwik\NoAccessException
     * @return array
     */
    protected function getGraphParamsModified($paramsToSet = array())
    {
        if (!isset($paramsToSet['period'])) {
            $period = Common::getRequestVar('period');
        } else {
            $period = $paramsToSet['period'];
        }
        if ($period == 'range') {
            return $paramsToSet;
        }
        if (!isset($paramsToSet['range'])) {
            $range = 'last30';
        } else {
            $range = $paramsToSet['range'];
        }

        if (!isset($paramsToSet['date'])) {
            $endDate = $this->strDate;
        } else {
            $endDate = $paramsToSet['date'];
        }

        if (is_null($this->site)) {
            throw new NoAccessException("Website not initialized, check that you are logged in and/or using the correct token_auth.");
        }
        $paramDate = Range::getRelativeToEndDate($period, $range, $endDate, $this->site);

        $params = array_merge($paramsToSet, array('date' => $paramDate));
        return $params;
    }

    /**
     * Returns a numeric value from the API.
     * Works only for API methods that originally returns numeric values (there is no cast here)
     *
     * @param string $methodToCall Name of method to call, eg. Referrers.getNumberOfDistinctSearchEngines
     * @param bool|string $date A custom date to use when getting the value. If false, the 'date' query
     *                                          parameter is used.
     *
     * @return int|float
     */
    protected function getNumericValue($methodToCall, $date = false)
    {
        $params = $date === false ? array() : array('date' => $date);

        $return = Request::processRequest($methodToCall, $params);
        $columns = $return->getFirstRow()->getColumns();
        return reset($columns);
    }

    /**
     * Returns a URL to a sparkline image for a report served by the current plugin.
     * 
     * The result of this URL should be used with the [sparkline()](/api-reference/Piwik/View#twig) twig function.
     * 
     * The current site ID and period will be used.
     * 
     * @param string $action Method name of the controller that serves the report.
     * @param array $customParameters The array of query parameter name/value pairs that
     *                                should be set in result URL.
     * @return string The generated URL.
     * @api
     */
    protected function getUrlSparkline($action, $customParameters = array())
    {
        $params = $this->getGraphParamsModified(
            array('viewDataTable' => 'sparkline',
                  'action'        => $action,
                  'module'        => $this->pluginName)
            + $customParameters
        );
        // convert array values to comma separated
        foreach ($params as &$value) {
            if (is_array($value)) {
                $value = rawurlencode(implode(',', $value));
            }
        }
        $url = Url::getCurrentQueryStringWithParametersModified($params);
        return $url;
    }

    /**
     * Sets the first date available in the period selector's calendar.
     *
     * @param Date $minDate The min date.
     * @param View $view The view that contains the period selector.
     * @api
     */
    protected function setMinDateView(Date $minDate, $view)
    {
        $view->minDateYear = $minDate->toString('Y');
        $view->minDateMonth = $minDate->toString('m');
        $view->minDateDay = $minDate->toString('d');
    }

    /**
     * Sets the last date available in the period selector's calendar. Usually this is just the "today" date
     * for a site (which varies based on the timezone of a site).
     *
     * @param Date $maxDate The max date.
     * @param View $view The view that contains the period selector.
     * @api
     */
    protected function setMaxDateView(Date $maxDate, $view)
    {
        $view->maxDateYear = $maxDate->toString('Y');
        $view->maxDateMonth = $maxDate->toString('m');
        $view->maxDateDay = $maxDate->toString('d');
    }

    /**
     * Assigns variables to {@link Piwik\View} instances that display an entire page.
     * 
     * The following variables assigned:
     * 
     * **date** - The value of the **date** query parameter.
     * **idSite** - The value of the **idSite** query parameter.
     * **rawDate** - The value of the **date** query parameter.
     * **prettyDate** - A pretty string description of the current period.
     * **siteName** - The current site's name.
     * **siteMainUrl** - The URL of the current site.
     * **startDate** - The start date of the current period. A {@link Piwik\Date} instance.
     * **endDate** - The end date of the current period. A {@link Piwik\Date} instance.
     * **language** - The current language's language code.
     * **config_action_url_category_delimiter** - The value of the `[General] action_url_category_delimiter`
     *                                            INI config option.
     * **topMenu** - The result of `MenuTop::getInstance()->getMenu()`.
     * 
     * As well as the variables set by {@link setPeriodVariablesView()}.
     * 
     * Will exit on error.
     * 
     * @param View $view
     * @return void
     * @api
     */
    protected function setGeneralVariablesView($view)
    {
        $view->date = $this->strDate;

        try {
            $view->idSite = $this->idSite;
            if (empty($this->site) || empty($this->idSite)) {
                throw new Exception("The requested website idSite is not found in the request, or is invalid.
				Please check that you are logged in Piwik and have permission to access the specified website.");
            }
            $this->setPeriodVariablesView($view);

            $rawDate = Common::getRequestVar('date');
            $periodStr = Common::getRequestVar('period');
            if ($periodStr != 'range') {
                $date = Date::factory($this->strDate);
                $period = Period::factory($periodStr, $date);
            } else {
                $period = new Range($periodStr, $rawDate, $this->site->getTimezone());
            }
            $view->rawDate = $rawDate;
            $view->prettyDate = self::getCalendarPrettyDate($period);

            $view->siteName = $this->site->getName();
            $view->siteMainUrl = $this->site->getMainUrl();

            $datetimeMinDate = $this->site->getCreationDate()->getDatetime();
            $minDate = Date::factory($datetimeMinDate, $this->site->getTimezone());
            $this->setMinDateView($minDate, $view);

            $maxDate = Date::factory('now', $this->site->getTimezone());
            $this->setMaxDateView($maxDate, $view);

            // Setting current period start & end dates, for pre-setting the calendar when "Date Range" is selected
            $dateStart = $period->getDateStart();
            if ($dateStart->isEarlier($minDate)) {
                $dateStart = $minDate;
            }
            $dateEnd = $period->getDateEnd();
            if ($dateEnd->isLater($maxDate)) {
                $dateEnd = $maxDate;
            }

            $view->startDate = $dateStart;
            $view->endDate = $dateEnd;

            $language = LanguagesManager::getLanguageForSession();
            $view->language = !empty($language) ? $language : LanguagesManager::getLanguageCodeForCurrentUser();

            $view->config_action_url_category_delimiter = PiwikConfig::getInstance()->General['action_url_category_delimiter'];

            $this->setBasicVariablesView($view);

            $view->topMenu       = MenuTop::getInstance()->getMenu();
            $view->notifications = NotificationManager::getAllNotificationsToDisplay();
            NotificationManager::cancelAllNonPersistent();
        } catch (Exception $e) {
            Piwik_ExitWithMessage($e->getMessage(), $e->getTraceAsString());
        }
    }

    /**
     * Assigns a set of generally useful variables to a {@link Piwik\View} instance.
     * 
     * The following variables assigned:
     * 
     * **debugTrackVisitsInsidePiwikUI** - The value of the `[Debug] track_visits_inside_piwik_ui`
     *                                     INI config option.
     * **isSuperUser** - True if the current user is the Super User, false if otherwise.
     * **hasSomeAdminAccess** - True if the current user has admin access to at least one site,
     *                          false if otherwise.
     * **isCustomLogo** - The value of the `branding_use_custom_logo` option.
     * **logoHeader** - The header logo URL to use.
     * **logoLarge** - The large logo URL to use.
     * **logoSVG** - The SVG logo URL to use.
     * **hasSVGLogo** - True if there is a SVG logo, false if otherwise.
     * **enableFrames** - The value of the `[General] enable_framed_pages` INI config option. If
     *                    true, {@link Piwik\View::setXFrameOptions()} is called on the view.
     * 
     * Also calls {@link setHostValidationVariablesView()}.
     *
     * @param View $view
     * @api
     */
    protected function setBasicVariablesView($view)
    {
        $view->debugTrackVisitsInsidePiwikUI = PiwikConfig::getInstance()->Debug['track_visits_inside_piwik_ui'];
        $view->isSuperUser = Access::getInstance()->hasSuperUserAccess();
        $view->hasSomeAdminAccess = Piwik::isUserHasSomeAdminAccess();

        $customLogo = new CustomLogo();
        $view->isCustomLogo = $customLogo->isEnabled();

        $view->logoHeader = \Piwik\Plugins\API\API::getInstance()->getHeaderLogoUrl();
        $view->logoLarge = \Piwik\Plugins\API\API::getInstance()->getLogoUrl();
        $view->logoSVG = \Piwik\Plugins\API\API::getInstance()->getSVGLogoUrl();
        $view->hasSVGLogo = \Piwik\Plugins\API\API::getInstance()->hasSVGLogo();

        $general = PiwikConfig::getInstance()->General;
        $view->enableFrames = $general['enable_framed_pages']
                || (isset($general['enable_framed_logins']) && $general['enable_framed_logins']);
        if (!$view->enableFrames) {
            $view->setXFrameOptions('sameorigin');
        }

        self::setHostValidationVariablesView($view);
    }

    /**
     * Checks if the current host is valid and sets variables on the given view, including:
     *
     * - **isValidHost** - true if host is valid, false if otherwise
     * - **invalidHostMessage** - message to display if host is invalid (only set if host is invalid)
     * - **invalidHost** - the invalid hostname (only set if host is invalid)
     * - **mailLinkStart** - the open tag of a link to email the Super User of this problem (only set
     *                       if host is invalid)
     *
     * @param View $view
     * @api
     */
    public static function setHostValidationVariablesView($view)
    {
        // check if host is valid
        $view->isValidHost = Url::isValidHost();
        if (!$view->isValidHost) {
            // invalid host, so display warning to user
            $validHost = PiwikConfig::getInstance()->General['trusted_hosts'][0];
            $invalidHost = Common::sanitizeInputValue($_SERVER['HTTP_HOST']);

            $emailSubject = rawurlencode(Piwik::translate('CoreHome_InjectedHostEmailSubject', $invalidHost));
            $emailBody = rawurlencode(Piwik::translate('CoreHome_InjectedHostEmailBody'));
            $superUserEmail = implode(',', Piwik::getAllSuperUserAccessEmailAddresses());

            $mailToUrl = "mailto:$superUserEmail?subject=$emailSubject&body=$emailBody";
            $mailLinkStart = "<a href=\"$mailToUrl\">";

            $invalidUrl = Url::getCurrentUrlWithoutQueryString($checkIfTrusted = false);
            $validUrl = Url::getCurrentScheme() . '://' . $validHost
                . Url::getCurrentScriptName();
            $invalidUrl = Common::sanitizeInputValue($invalidUrl);
            $validUrl = Common::sanitizeInputValue($validUrl);

            $changeTrustedHostsUrl = "index.php"
                . Url::getCurrentQueryStringWithParametersModified(array(
                                                                        'module' => 'CoreAdminHome',
                                                                        'action' => 'generalSettings'
                                                                   ))
                . "#trustedHostsSection";

            $warningStart = Piwik::translate('CoreHome_InjectedHostWarningIntro', array(
                                                                                      '<strong>' . $invalidUrl . '</strong>',
                                                                                      '<strong>' . $validUrl . '</strong>'
                                                                                 )) . ' <br/>';

            if (Piwik::hasUserSuperUserAccess()) {
                $view->invalidHostMessage = $warningStart . ' '
                    . Piwik::translate('CoreHome_InjectedHostSuperUserWarning', array(
                                                                                    "<a href=\"$changeTrustedHostsUrl\">",
                                                                                    $invalidHost,
                                                                                    '</a>',
                                                                                    "<br/><a href=\"$validUrl\">",
                                                                                    $validHost,
                                                                                    '</a>'
                                                                               ));
            } else if (Piwik::isUserIsAnonymous()) {
                $view->invalidHostMessage = $warningStart . ' '
                    . Piwik::translate('CoreHome_InjectedHostNonSuperUserWarning', array(
                        "<br/><a href=\"$validUrl\">",
                        '</a>',
                        '<span style="display:none">',
                        '</span>'
                    ));
            } else {
                $view->invalidHostMessage = $warningStart . ' '
                    . Piwik::translate('CoreHome_InjectedHostNonSuperUserWarning', array(
                                                                                       "<br/><a href=\"$validUrl\">",
                                                                                       '</a>',
                                                                                       $mailLinkStart,
                                                                                       '</a>'
                                                                                  ));
            }
            $view->invalidHostMessageHowToFix = '<p><b>How do I fix this problem and how do I login again?</b><br/> The Piwik Super User can manually edit the file piwik/config/config.ini.php
						and add the following lines: <pre>[General]' . "\n" . 'trusted_hosts[] = "' . $invalidHost . '"</pre>After making the change, you will be able to login again.</p>
						<p>You may also <i>disable this security feature (not recommended)</i>. To do so edit config/config.ini.php and add:
						<pre>[General]' . "\n" . 'enable_trusted_host_check=0</pre>';

            $view->invalidHost = $invalidHost; // for UserSettings warning
            $view->invalidHostMailLinkStart = $mailLinkStart;
        }
    }

    /**
     * Sets general period variables on a view, including:
     * 
     * - **displayUniqueVisitors** - Whether unique visitors should be displayed for the current
     *                               period.
     * - **period** - The value of the **period** query parameter.
     * - **otherPeriods** - `array('day', 'week', 'month', 'year', 'range')`
     * - **periodsNames** - List of available periods mapped to their singular and plural translations.
     *
     * @param View $view
     * @throws Exception if the current period is invalid.
     * @api
     */
    public static function setPeriodVariablesView($view)
    {
        if (isset($view->period)) {
            return;
        }

        $currentPeriod = Common::getRequestVar('period');
        $view->displayUniqueVisitors = SettingsPiwik::isUniqueVisitorsEnabled($currentPeriod);
        $availablePeriods = array('day', 'week', 'month', 'year', 'range');
        if (!in_array($currentPeriod, $availablePeriods)) {
            throw new Exception("Period must be one of: " . implode(",", $availablePeriods));
        }
        $periodNames = array(
            'day'   => array('singular' => Piwik::translate('CoreHome_PeriodDay'), 'plural' => Piwik::translate('CoreHome_PeriodDays')),
            'week'  => array('singular' => Piwik::translate('CoreHome_PeriodWeek'), 'plural' => Piwik::translate('CoreHome_PeriodWeeks')),
            'month' => array('singular' => Piwik::translate('CoreHome_PeriodMonth'), 'plural' => Piwik::translate('CoreHome_PeriodMonths')),
            'year'  => array('singular' => Piwik::translate('CoreHome_PeriodYear'), 'plural' => Piwik::translate('CoreHome_PeriodYears')),
            // Note: plural is not used for date range
            'range' => array('singular' => Piwik::translate('General_DateRangeInPeriodList'), 'plural' => Piwik::translate('General_DateRangeInPeriodList')),
        );

        $found = array_search($currentPeriod, $availablePeriods);
        if ($found !== false) {
            unset($availablePeriods[$found]);
        }
        $view->period = $currentPeriod;
        $view->otherPeriods = $availablePeriods;
        $view->periodsNames = $periodNames;
    }

    /**
     * Helper method used to redirect the current HTTP request to another module/action.
     * 
     * This function will exit immediately after executing.
     *
     * @param string $moduleToRedirect The plugin to redirect to, eg. `"MultiSites"`.
     * @param string $actionToRedirect Action, eg. `"index"`.
     * @param int|null $websiteId The new idSite query parameter, eg, `1`.
     * @param string|null $defaultPeriod The new period query parameter, eg, `'day'`.
     * @param string|null $defaultDate The new date query parameter, eg, `'today'`.
     * @param array $parameters Other query parameters to append to the URL.
     * @api
     */
    public function redirectToIndex($moduleToRedirect, $actionToRedirect, $websiteId = null, $defaultPeriod = null,
                                    $defaultDate = null, $parameters = array())
    {
        if (empty($websiteId)) {
            $websiteId = $this->getDefaultWebsiteId();
        }
        if (empty($defaultDate)) {
            $defaultDate = $this->getDefaultDate();
        }
        if (empty($defaultPeriod)) {
            $defaultPeriod = $this->getDefaultPeriod();
        }
        $parametersString = '';
        if (!empty($parameters)) {
            $parametersString = '&' . Url::getQueryStringFromParameters($parameters);
        }

        if ($websiteId) {
            $url = "Location: index.php?module=" . $moduleToRedirect
                . "&action=" . $actionToRedirect
                . "&idSite=" . $websiteId
                . "&period=" . $defaultPeriod
                . "&date=" . $defaultDate
                . $parametersString;
            header($url);
            exit;
        }

        if (Piwik::hasUserSuperUserAccess()) {
            Piwik_ExitWithMessage("Error: no website was found in this Piwik installation.
			<br />Check the table '" . Common::prefixTable('site') . "' in your database, it should contain your Piwik websites.", false, true);
        }

        $currentLogin = Piwik::getCurrentUserLogin();
        if (!empty($currentLogin)
            && $currentLogin != 'anonymous'
        ) {
            $emails = implode(',', Piwik::getAllSuperUserAccessEmailAddresses());
            $errorMessage = sprintf(Piwik::translate('CoreHome_NoPrivilegesAskPiwikAdmin'), $currentLogin, "<br/><a href='mailto:" . $emails . "?subject=Access to Piwik for user $currentLogin'>", "</a>");
            $errorMessage .= "<br /><br />&nbsp;&nbsp;&nbsp;<b><a href='index.php?module=" . Registry::get('auth')->getName() . "&amp;action=logout'>&rsaquo; " . Piwik::translate('General_Logout') . "</a></b><br />";
            Piwik_ExitWithMessage($errorMessage, false, true);
        }

        echo FrontController::getInstance()->dispatch(Piwik::getLoginPluginName(), false);
        exit;
    }

    /**
     * Returns default site ID that Piwik should load.
     * 
     * _Note: This value is a Piwik setting set by each user._
     *
     * @return bool|int
     * @api
     */
    protected function getDefaultWebsiteId()
    {
        $defaultWebsiteId = false;

        // User preference: default website ID to load
        $defaultReport = APIUsersManager::getInstance()->getUserPreference(Piwik::getCurrentUserLogin(), APIUsersManager::PREFERENCE_DEFAULT_REPORT);
        if (is_numeric($defaultReport)) {
            $defaultWebsiteId = $defaultReport;
        }

        if ($defaultWebsiteId && Piwik::isUserHasViewAccess($defaultWebsiteId)) {
            return $defaultWebsiteId;
        }

        $sitesId = APISitesManager::getInstance()->getSitesIdWithAtLeastViewAccess();
        if (!empty($sitesId)) {
            return $sitesId[0];
        }
        return false;
    }

    /**
     * Returns default date for Piwik reports.
     *
     * _Note: This value is a Piwik setting set by each user._
     * 
     * @return string `'today'`, `'2010-01-01'`, etc.
     * @api
     */
    protected function getDefaultDate()
    {
        // NOTE: a change in this function might mean a change in plugins/UsersManager/javascripts/usersSettings.js as well
        $userSettingsDate = APIUsersManager::getInstance()->getUserPreference(Piwik::getCurrentUserLogin(), APIUsersManager::PREFERENCE_DEFAULT_REPORT_DATE);
        if ($userSettingsDate == 'yesterday') {
            return $userSettingsDate;
        }
        // if last7, last30, etc.
        if (strpos($userSettingsDate, 'last') === 0
            || strpos($userSettingsDate, 'previous') === 0
        ) {
            return $userSettingsDate;
        }
        return 'today';
    }

    /**
     * Returns default period type for Piwik reports.
     *
     * @return string `'day'`, `'week'`, `'month'`, `'year'` or `'range'`
     * @api
     */
    protected function getDefaultPeriod()
    {
        $userSettingsDate = APIUsersManager::getInstance()->getUserPreference(Piwik::getCurrentUserLogin(), APIUsersManager::PREFERENCE_DEFAULT_REPORT_DATE);
        if ($userSettingsDate === false) {
            return PiwikConfig::getInstance()->General['default_period'];
        }
        if (in_array($userSettingsDate, array('today', 'yesterday'))) {
            return 'day';
        }
        if (strpos($userSettingsDate, 'last') === 0
            || strpos($userSettingsDate, 'previous') === 0
        ) {
            return 'range';
        }
        return $userSettingsDate;
    }

    /**
     * Checks that the token_auth in the URL matches the currently logged-in user's token_auth.
     * 
     * This is a protection against CSRF and should be used in all controller
     * methods that modify Piwik or any user settings.
     * 
     * **The token_auth should never appear in the browser's address bar.**
     *
     * @throws \Piwik\NoAccessException If the token doesn't match.
     * @api
     */
    protected function checkTokenInUrl()
    {
        if (Common::getRequestVar('token_auth', false) != Piwik::getCurrentUserTokenAuth()) {
            throw new NoAccessException(Piwik::translate('General_ExceptionInvalidToken'));
        }
    }

    /**
     * Returns a prettified date string for use in period selector widget.
     *
     * @param Period $period The period to return a pretty string for.
     * @return string
     * @api
     */
    public static function getCalendarPrettyDate($period)
    {
        if ($period instanceof Month) // show month name when period is for a month
        {
            return $period->getLocalizedLongString();
        } else {
            return $period->getPrettyString();
        }
    }

    /**
     * Returns the pretty date representation
     *
     * @param $date string
     * @param $period string
     * @return string Pretty date
     */
    public static function getPrettyDate($date, $period)
    {
        return self::getCalendarPrettyDate(Period::factory($period, Date::factory($date)));
    }

    /**
     * Calculates the evolution from one value to another and returns HTML displaying
     * the evolution percent. The HTML includes an up/down arrow and is colored red, black or
     * green depending on whether the evolution is negative, 0 or positive.
     *
     * No HTML is returned if the current value and evolution percent are both 0.
     *
     * @param string $date The date of the current value.
     * @param int $currentValue The value to calculate evolution to.
     * @param string $pastDate The date of past value.
     * @param int $pastValue The value in the past to calculate evolution from.
     * @return string|false The HTML or `false` if the evolution is 0 and the current value is 0.
     * @api
     */
    protected function getEvolutionHtml($date, $currentValue, $pastDate, $pastValue)
    {
        $evolutionPercent = CalculateEvolutionFilter::calculate(
            $currentValue, $pastValue, $precision = 1);

        // do not display evolution if evolution percent is 0 and current value is 0
        if ($evolutionPercent == 0
            && $currentValue == 0
        ) {
            return false;
        }

        $titleEvolutionPercent = $evolutionPercent;
        if ($evolutionPercent < 0) {
            $class = "negative-evolution";
            $img = "arrow_down.png";
        } else if ($evolutionPercent == 0) {
            $class = "neutral-evolution";
            $img = "stop.png";
        } else {
            $class = "positive-evolution";
            $img = "arrow_up.png";
            $titleEvolutionPercent = '+' . $titleEvolutionPercent;
        }

        $title = Piwik::translate('General_EvolutionSummaryGeneric', array(
                                                                         Piwik::translate('General_NVisits', $currentValue),
                                                                         $date,
                                                                         Piwik::translate('General_NVisits', $pastValue),
                                                                         $pastDate,
                                                                         $titleEvolutionPercent
                                                                    ));

        $result = '<span class="metricEvolution" title="' . $title
            . '"><img style="padding-right:4px" src="plugins/MultiSites/images/' . $img . '"/><strong';

        if (isset($class)) {
            $result .= ' class="' . $class . '"';
        }
        $result .= '>' . $evolutionPercent . '</strong></span>';

        return $result;
    }
}