<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle 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 3 of the License, or
// (at your option) any later version.
//
// Moodle 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.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**
 * Moodle site analysable.
 *
 * @package   core_analytics
 * @copyright 2016 David Monllao {@link http://www.davidmonllao.com}
 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

namespace core_analytics;

defined('MOODLE_INTERNAL') || die();

/**
 * Moodle site analysable.
 *
 * @package   core_analytics
 * @copyright 2016 David Monllao {@link http://www.davidmonllao.com}
 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
class site implements \core_analytics\analysable {

    /**
     * @var int
     */
    protected $start;

    /**
     * @var int
     */
    protected $end;

    /**
     * Analysable id
     *
     * @return int
     */
    public function get_id() {
        return SYSCONTEXTID;
    }

    /**
     * Analysable context.
     *
     * @return \context
     */
    public function get_context() {
        return \context_system::instance();
    }

    /**
     * Analysable start timestamp.
     *
     * @return int
     */
    public function get_start() {
        if (!empty($this->start)) {
            return $this->start;
        }

        $logstore = \core_analytics\manager::get_analytics_logstore();
        // Basically a SELECT MIN(timecreated) FROM ...
        $events = $logstore->get_events_select("", array(), "timecreated ASC", 0, 1);
        if ($events) {
            // There should be just 1 event.
            $event = reset($events);
            $this->start = $event->timecreated;
        } else {
            $this->start = 0;
        }

        return $this->start;
    }

    /**
     * Analysable end timestamp.
     *
     * @return int
     */
    public function get_end() {
        if (!empty($this->end)) {
            return $this->end;
        }

        $logstore = \core_analytics\manager::get_analytics_logstore();
        // Basically a SELECT MAX(timecreated) FROM ...
        $events = $logstore->get_events_select("", array(), "timecreated DESC", 0, 1);
        if ($events) {
            // There should be just 1 event.
            $event = reset($events);
            $this->end = $event->timecreated;
        } else {
            $this->end = time();
        }

        return $this->end;
    }
}