<?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/>.

/**
 * Base renderer for outputting course formats.
 *
 * @package core
 * @copyright 2012 Dan Poltawski
 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 * @since Moodle 2.3
 */

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


/**
 * This is a convenience renderer which can be used by section based formats
 * to reduce code duplication. It is not necessary for all course formats to
 * use this and its likely to change in future releases.
 *
 * @package core
 * @copyright 2012 Dan Poltawski
 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 * @since Moodle 2.3
 */
abstract class format_section_renderer_base extends plugin_renderer_base {

    /**
     * Generate the starting container html for a list of sections
     * @return string HTML to output.
     */
    abstract protected function start_section_list();

    /**
     * Generate the closing container html for a list of sections
     * @return string HTML to output.
     */
    abstract protected function end_section_list();

    /**
     * Generate the title for this section page
     * @return string the page title
     */
    abstract protected function page_title();

    /**
     * Generate the content to displayed on the right part of a section
     * before course modules are included
     *
     * @param stdClass $section The course_section entry from DB
     * @param stdClass $course The course entry from DB
     * @param bool $onsectionpage true if being printed on a section page
     * @return string HTML to output.
     */
    protected function section_right_content($section, $course, $onsectionpage) {
        $o = $this->output->spacer();

        if ($section->section != 0) {
            $controls = $this->section_edit_controls($course, $section, $onsectionpage);
            if (!empty($controls)) {
                $o = implode('<br />', $controls);
            }
        }

        return $o;
    }

    /**
     * Generate the content to displayed on the left part of a section
     * before course modules are included
     *
     * @param stdClass $section The course_section entry from DB
     * @param stdClass $course The course entry from DB
     * @param bool $onsectionpage true if being printed on a section page
     * @return string HTML to output.
     */
    protected function section_left_content($section, $course, $onsectionpage) {
        $o = $this->output->spacer();

        if ($section->section != 0) {
            // Only in the non-general sections.
            if ($this->is_section_current($section, $course)) {
                $o = get_accesshide(get_string('currentsection', 'format_'.$course->format));
            }
        }

        return $o;
    }

    /**
     * Generate the display of the header part of a section before
     * course modules are included
     *
     * @param stdClass $section The course_section entry from DB
     * @param stdClass $course The course entry from DB
     * @param bool $onsectionpage true if being printed on a section page
     * @return string HTML to output.
     */
    protected function section_header($section, $course, $onsectionpage) {
        global $PAGE;

        $o = '';
        $currenttext = '';
        $sectionstyle = '';
        $linktitle = false;

        if ($section->section != 0) {
            // Only in the non-general sections.
            if (!$section->visible) {
                $sectionstyle = ' hidden';
            } else if ($this->is_section_current($section, $course)) {
                $sectionstyle = ' current';
            }
            $linktitle = ($course->coursedisplay == COURSE_DISPLAY_MULTIPAGE);
        }

        $o.= html_writer::start_tag('li', array('id' => 'section-'.$section->section,
            'class' => 'section main clearfix'.$sectionstyle));

        $leftcontent = $this->section_left_content($section, $course, $onsectionpage);
        $o.= html_writer::tag('div', $leftcontent, array('class' => 'left side'));

        $rightcontent = $this->section_right_content($section, $course, $onsectionpage);
        $o.= html_writer::tag('div', $rightcontent, array('class' => 'right side'));
        $o.= html_writer::start_tag('div', array('class' => 'content'));

        if (!$onsectionpage) {
            $title = get_section_name($course, $section);
            if ($linktitle) {
                $title = html_writer::link(course_get_url($course, $section->section), $title);
            }
            $o.= $this->output->heading($title, 3, 'sectionname');
        }

        $o.= html_writer::start_tag('div', array('class' => 'summary'));
        $o.= $this->format_summary_text($section);

        $context = context_course::instance($course->id);
        if ($PAGE->user_is_editing() && has_capability('moodle/course:update', $context)) {
            $url = new moodle_url('/course/editsection.php', array('id'=>$section->id));

            if ($onsectionpage) {
                $url->param('sectionreturn', 1);
            }

            $o.= html_writer::link($url,
                html_writer::empty_tag('img', array('src' => $this->output->pix_url('t/edit'), 'class' => 'iconsmall edit')),
                array('title' => get_string('editsummary')));
        }
        $o.= html_writer::end_tag('div');

        $o .= $this->section_availability_message($section);

        return $o;
    }

    /**
     * Generate the display of the footer part of a section
     *
     * @return string HTML to output.
     */
    protected function section_footer() {
        $o = html_writer::end_tag('div');
        $o.= html_writer::end_tag('li');

        return $o;
    }

    /**
     * Generate the edit controls of a section
     *
     * @param stdClass $course The course entry from DB
     * @param stdClass $section The course_section entry from DB
     * @param bool $onsectionpage true if being printed on a section page
     * @return array of links with edit controls
     */
    protected function section_edit_controls($course, $section, $onsectionpage = false) {
        global $PAGE;

        if (!$PAGE->user_is_editing()) {
            return array();
        }

        if (!has_capability('moodle/course:update', context_course::instance($course->id))) {
            return array();
        }

        if ($onsectionpage) {
            $baseurl = course_get_url($course, $section->section);
        } else {
            $baseurl = course_get_url($course);
        }
        $baseurl->param('sesskey', sesskey());

        $controls = array();

        $url = clone($baseurl);
        if ($section->visible) { // Show the hide/show eye.
            $strhidefromothers = get_string('hidefromothers', 'format_'.$course->format);
            $url->param('hide', $section->section);
            $controls[] = html_writer::link($url,
                html_writer::empty_tag('img', array('src' => $this->output->pix_url('i/hide'),
                'class' => 'icon hide', 'alt' => $strhidefromothers)),
                array('title' => $strhidefromothers, 'class' => 'editing_showhide'));
        } else {
            $strshowfromothers = get_string('showfromothers', 'format_'.$course->format);
            $url->param('show',  $section->section);
            $controls[] = html_writer::link($url,
                html_writer::empty_tag('img', array('src' => $this->output->pix_url('i/show'),
                'class' => 'icon hide', 'alt' => $strshowfromothers)),
                array('title' => $strshowfromothers, 'class' => 'editing_showhide'));
        }

        if (!$onsectionpage) {
            $url = clone($baseurl);
            if ($section->section > 1) { // Add a arrow to move section up.
                $url->param('section', $section->section);
                $url->param('move', -1);
                $strmoveup = get_string('moveup');

                $controls[] = html_writer::link($url,
                    html_writer::empty_tag('img', array('src' => $this->output->pix_url('t/up'),
                    'class' => 'icon up', 'alt' => $strmoveup)),
                    array('title' => $strmoveup, 'class' => 'moveup'));
            }

            $url = clone($baseurl);
            if ($section->section < $course->numsections) { // Add a arrow to move section down.
                $url->param('section', $section->section);
                $url->param('move', 1);
                $strmovedown =  get_string('movedown');

                $controls[] = html_writer::link($url,
                    html_writer::empty_tag('img', array('src' => $this->output->pix_url('t/down'),
                    'class' => 'icon down', 'alt' => $strmovedown)),
                    array('title' => $strmovedown, 'class' => 'movedown'));
            }
        }

        return $controls;
    }

    /**
     * Generate a summary of a section for display on the 'coruse index page'
     *
     * @param stdClass $section The course_section entry from DB
     * @param stdClass $course The course entry from DB
     * @return string HTML to output.
     */
    protected function section_summary($section, $course) {
        // If section is hidden then display grey section link
        $classattr = 'section-summary clearfix';
        If (!$section->visible) {
            $classattr .= ' dimmed_text';
        }

        $o = '';
        $o.= html_writer::start_tag('li', array('id' => 'section-'.$section->section,
            'class' => $classattr));

        $title = get_section_name($course, $section);
        $o.= html_writer::start_tag('a', array('href' => course_get_url($course, $section->section)));
        $o.= $this->output->heading($title, 3, 'header section-title');
        $o.= html_writer::end_tag('a');

        $o.= html_writer::start_tag('div', array('class' => 'summarytext'));
        $o.= $this->format_summary_text($section);
        $o.= html_writer::end_tag('div');

        $o .= $this->section_availability_message($section);

        $o.= html_writer::end_tag('li');

        return $o;
    }

    /**
     * If section is not visible to current user, display the message about that
     * ('Not available until...', that sort of thing). Otherwise, returns blank.
     *
     * @param stdClass $section The course_section entry from DB
     * @return string HTML to output
     */
    protected function section_availability_message($section) {
        $o = '';
        if (!$section->uservisible || $section->availableinfo) {
            $o .= html_writer::start_tag('div', array('class' => 'availabilityinfo'));
            if (!empty($section->availableinfo)) {
                $o .= $section->availableinfo;
            } else {
                $o .= get_string('notavailable');
            }
            $o .= html_writer::end_tag('div');
        }
        return $o;
    }

    /**
     * Show if something is on on the course clipboard (moving around)
     *
     * @param stdClass $course The course entry from DB
     * @param int $sectionno The section number in the coruse which is being dsiplayed
     * @return string HTML to output.
     */
    protected function course_activity_clipboard($course, $sectionno = 0) {
        global $USER;

        $o = '';
        // If currently moving a file then show the current clipboard.
        if (ismoving($course->id)) {
            $url = new moodle_url('/course/mod.php',
                array('sesskey' => sesskey(),
                      'cancelcopy' => true,
                      'sr' => $sectionno,
                )
            );

            $strcancel= get_string('cancel');

            $o.= html_writer::start_tag('li', array('class' => 'clipboard'));
            $o.= strip_tags(get_string('activityclipboard', '', $USER->activitycopyname));
            $o.= ' ('.html_writer::link($url, get_string('cancel')).')';
            $o.= html_writer::end_tag('li');
        }

        return $o;
    }

    /**
     * Generate next/previous section links for naviation
     *
     * @param stdClass $course The course entry from DB
     * @param array $sections The course_sections entries from the DB
     * @param int $sectionno The section number in the coruse which is being dsiplayed
     * @return array associative array with previous and next section link
     */
    protected function get_nav_links($course, $sections, $sectionno) {
        // FIXME: This is really evil and should by using the navigation API.
        $canviewhidden = has_capability('moodle/course:viewhiddensections', context_course::instance($course->id))
            or !$course->hiddensections;

        $links = array('previous' => '', 'next' => '');
        $back = $sectionno - 1;
        while ($back > 0 and empty($links['previous'])) {
            if ($canviewhidden || $sections[$back]->visible) {
                $params = array();
                if (!$sections[$back]->visible) {
                    $params = array('class' => 'dimmed_text');
                }
                $previouslink = html_writer::tag('span', $this->output->larrow(), array('class' => 'larrow'));
                $previouslink .= get_section_name($course, $sections[$back]);
                $links['previous'] = html_writer::link(course_get_url($course, $back), $previouslink, $params);
            }
            $back--;
        }

        $forward = $sectionno + 1;
        while ($forward <= $course->numsections and empty($links['next'])) {
            if ($canviewhidden || $sections[$forward]->visible) {
                $params = array();
                if (!$sections[$forward]->visible) {
                    $params = array('class' => 'dimmed_text');
                }
                $nextlink = get_section_name($course, $sections[$forward]);
                $nextlink .= html_writer::tag('span', $this->output->rarrow(), array('class' => 'rarrow'));
                $links['next'] = html_writer::link(course_get_url($course, $forward), $nextlink, $params);
            }
            $forward++;
        }

        return $links;
    }

    /**
     * Generate the header html of a stealth section
     *
     * @param int $sectionno The section number in the coruse which is being dsiplayed
     * @return string HTML to output.
     */
    protected function stealth_section_header($sectionno) {
        $o = '';
        $o.= html_writer::start_tag('li', array('id' => 'section-'.$sectionno, 'class' => 'section main clearfix orphaned hidden'));
        $o.= html_writer::tag('div', '', array('class' => 'left side'));
        $o.= html_writer::tag('div', '', array('class' => 'right side'));
        $o.= html_writer::start_tag('div', array('class' => 'content'));
        $o.= $this->output->heading(get_string('orphanedactivities'), 3, 'sectionname');
        return $o;
    }

    /**
     * Generate footer html of a stealth section
     *
     * @return string HTML to output.
     */
    protected function stealth_section_footer() {
        $o = html_writer::end_tag('div');
        $o.= html_writer::end_tag('li');
        return $o;
    }

    /**
     * Generate the html for a hidden section
     *
     * @param int $sectionno The section number in the coruse which is being dsiplayed
     * @return string HTML to output.
     */
    protected function section_hidden($sectionno) {
        $o = '';
        $o.= html_writer::start_tag('li', array('id' => 'section-'.$sectionno, 'class' => 'section main clearfix hidden'));
        $o.= html_writer::tag('div', '', array('class' => 'left side'));
        $o.= html_writer::tag('div', '', array('class' => 'right side'));
        $o.= html_writer::start_tag('div', array('class' => 'content'));
        $o.= get_string('notavailable');
        $o.= html_writer::end_tag('div');
        $o.= html_writer::end_tag('li');
        return $o;
    }

    /**
     * Output the html for a single section page .
     *
     * @param stdClass $course The course entry from DB
     * @param array $sections The course_sections entries from the DB
     * @param array $mods used for print_section()
     * @param array $modnames used for print_section()
     * @param array $modnamesused used for print_section()
     * @param int $displaysection The section number in the course which is being displayed
     */
    public function print_single_section_page($course, $sections, $mods, $modnames, $modnamesused, $displaysection) {
        global $PAGE;

        // Can we view the section in question?
        $context = context_course::instance($course->id);
        $canviewhidden = has_capability('moodle/course:viewhiddensections', $context);

        if (!isset($sections[$displaysection])) {
            // This section doesn't exist
            print_error('unknowncoursesection', 'error', null, $course->fullname);
            return;
        }

        if (!$sections[$displaysection]->visible && !$canviewhidden) {
            if (!$course->hiddensections) {
                echo $this->start_section_list();
                echo $this->section_hidden($displaysection);
                echo $this->end_section_list();
            }
            // Can't view this section.
            return;
        }

        // General section if non-empty.
        $thissection = $sections[0];
        if ($thissection->summary or $thissection->sequence or $PAGE->user_is_editing()) {
            echo $this->start_section_list();
            echo $this->section_header($thissection, $course, true);
            print_section($course, $thissection, $mods, $modnamesused, true);
            if ($PAGE->user_is_editing()) {
                print_section_add_menus($course, 0, $modnames);
            }
            echo $this->section_footer();
            echo $this->end_section_list();
        }

        // Start single-section div
        echo html_writer::start_tag('div', array('class' => 'single-section'));

        // Title with section navigation links.
        $sectionnavlinks = $this->get_nav_links($course, $sections, $displaysection);
        $sectiontitle = '';
        $sectiontitle .= html_writer::start_tag('div', array('class' => 'section-navigation header headingblock'));
        $sectiontitle .= html_writer::tag('span', $sectionnavlinks['previous'], array('class' => 'mdl-left'));
        $sectiontitle .= html_writer::tag('span', $sectionnavlinks['next'], array('class' => 'mdl-right'));
        // Title attributes
        $titleattr = 'mdl-align title';
        if (!$sections[$displaysection]->visible) {
            $titleattr .= ' dimmed_text';
        }
        $sectiontitle .= html_writer::tag('div', get_section_name($course, $sections[$displaysection]), array('class' => $titleattr));
        $sectiontitle .= html_writer::end_tag('div');
        echo $sectiontitle;

        // Copy activity clipboard..
        echo $this->course_activity_clipboard($course, $displaysection);

        // Now the list of sections..
        echo $this->start_section_list();

        // The requested section page.
        $thissection = $sections[$displaysection];
        echo $this->section_header($thissection, $course, true);
        // Show completion help icon.
        $completioninfo = new completion_info($course);
        echo $completioninfo->display_help_icon();

        print_section($course, $thissection, $mods, $modnamesused, true);
        if ($PAGE->user_is_editing()) {
            print_section_add_menus($course, $displaysection, $modnames);
        }
        echo $this->section_footer();
        echo $this->end_section_list();

        // Display section bottom navigation.
        $courselink = html_writer::link(course_get_url($course), get_string('returntomaincoursepage'));
        $sectionbottomnav = '';
        $sectionbottomnav .= html_writer::start_tag('div', array('class' => 'section-navigation mdl-bottom'));
        $sectionbottomnav .= html_writer::tag('span', $sectionnavlinks['previous'], array('class' => 'mdl-left'));
        $sectionbottomnav .= html_writer::tag('span', $sectionnavlinks['next'], array('class' => 'mdl-right'));
        $sectionbottomnav .= html_writer::tag('div', $courselink, array('class' => 'mdl-align'));
        $sectionbottomnav .= html_writer::end_tag('div');
        echo $sectionbottomnav;

        // close single-section div.
        echo html_writer::end_tag('div');
    }

    /**
     * Output the html for a multiple section page
     *
     * @param stdClass $course The course entry from DB
     * @param array $sections The course_sections entries from the DB
     * @param array $mods used for print_section()
     * @param array $modnames used for print_section()
     * @param array $modnamesused used for print_section()
     */
    public function print_multiple_section_page($course, $sections, $mods, $modnames, $modnamesused) {
        global $PAGE;

        $context = context_course::instance($course->id);
        // Title with completion help icon.
        $completioninfo = new completion_info($course);
        echo $completioninfo->display_help_icon();
        echo $this->output->heading($this->page_title(), 2, 'accesshide');

        // Copy activity clipboard..
        echo $this->course_activity_clipboard($course);

        // Now the list of sections..
        echo $this->start_section_list();

        // General section if non-empty.
        $thissection = $sections[0];
        unset($sections[0]);
        if ($thissection->summary or $thissection->sequence or $PAGE->user_is_editing()) {
            echo $this->section_header($thissection, $course, true);
            print_section($course, $thissection, $mods, $modnamesused, true);
            if ($PAGE->user_is_editing()) {
                print_section_add_menus($course, 0, $modnames);
            }
            echo $this->section_footer();
        }

        $canviewhidden = has_capability('moodle/course:viewhiddensections', $context);
        for ($section = 1; $section <= $course->numsections; $section++) {
            if (!empty($sections[$section])) {
                $thissection = $sections[$section];
            } else {
                // This will create a course section if it doesn't exist..
                $thissection = get_course_section($section, $course->id);

                // The returned section is only a bare database object rather than
                // a section_info object - we will need at least the uservisible
                // field in it.
                $thissection->uservisible = true;
                $thissection->availableinfo = null;
                $thissection->showavailability = 0;
            }
            // Show the section if the user is permitted to access it, OR if it's not available
            // but showavailability is turned on
            $showsection = $thissection->uservisible ||
                    ($thissection->visible && !$thissection->available && $thissection->showavailability);
            if (!$showsection) {
                // Hidden section message is overridden by 'unavailable' control
                // (showavailability option).
                if (!$course->hiddensections && $thissection->available) {
                    echo $this->section_hidden($section);
                }

                unset($sections[$section]);
                continue;
            }

            if (!$PAGE->user_is_editing() && $course->coursedisplay == COURSE_DISPLAY_MULTIPAGE) {
                // Display section summary only.
                echo $this->section_summary($thissection, $course);
            } else {
                echo $this->section_header($thissection, $course, false);
                if ($thissection->uservisible) {
                    print_section($course, $thissection, $mods, $modnamesused);
                    if ($PAGE->user_is_editing()) {
                        print_section_add_menus($course, $section, $modnames);
                    }
                }
                echo $this->section_footer();
            }

            unset($sections[$section]);
        }

        if ($PAGE->user_is_editing() and has_capability('moodle/course:update', $context)) {
            // Print stealth sections if present.
            $modinfo = get_fast_modinfo($course);
            foreach ($sections as $section => $thissection) {
                if (empty($modinfo->sections[$section])) {
                    continue;
                }
                echo $this->stealth_section_header($section);
                print_section($course, $thissection, $mods, $modnamesused);
                echo $this->stealth_section_footer();
            }

            echo $this->end_section_list();

            echo html_writer::start_tag('div', array('class' => 'mdl-right'));

            // Increase number of sections.
            $straddsection = get_string('increasesections', 'moodle');
            $url = new moodle_url('/course/changenumsections.php',
                array('courseid' => $course->id,
                      'increase' => true,
                      'sesskey' => sesskey()));
            $icon = $this->output->pix_icon('t/switch_plus', $straddsection);
            echo html_writer::link($url, $icon.get_accesshide($straddsection), array('class' => 'increase-sections'));

            if ($course->numsections > 0) {
                // Reduce number of sections sections.
                $strremovesection = get_string('reducesections', 'moodle');
                $url = new moodle_url('/course/changenumsections.php',
                    array('courseid' => $course->id,
                          'increase' => false,
                          'sesskey' => sesskey()));
                $icon = $this->output->pix_icon('t/switch_minus', $strremovesection);
                echo html_writer::link($url, $icon.get_accesshide($strremovesection), array('class' => 'reduce-sections'));
            }

            echo html_writer::end_tag('div');
        } else {
            echo $this->end_section_list();
        }

    }

    /**
     * Generate html for a section summary text
     *
     * @param stdClass $section The course_section entry from DB
     * @return string HTML to output.
     */
    protected function format_summary_text($section) {
        $context = context_course::instance($section->course);
        $summarytext = file_rewrite_pluginfile_urls($section->summary, 'pluginfile.php',
            $context->id, 'course', 'section', $section->id);

        $options = new stdClass();
        $options->noclean = true;
        $options->overflowdiv = true;
        return format_text($summarytext, $section->summaryformat, $options);
    }

    /**
     * Is the section passed in the current section? (Note this isn't strictly
     * a renderering method, but neater here).
     *
     * @param stdClass $course The course entry from DB
     * @param stdClass $section The course_section entry from the DB
     * @return bool true if the section is current
     */
    protected function is_section_current($section, $course) {
        return ($course->marker == $section->section);
    }
}