<?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/>.

/**
 * Mandatory public API of imscp module
 *
 * @package   mod-imscp
 * @copyright 2009 Petr Skoda (http://skodak.org)
 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

/**
 * List of features supported in IMS CP module
 * @param string $feature FEATURE_xx constant for requested feature
 * @return mixed True if module supports feature, false if not, null if doesn't know
 */
function imscp_supports($feature) {
    switch($feature) {
        case FEATURE_MOD_ARCHETYPE:           return MOD_ARCHETYPE_RESOURCE;
        case FEATURE_GROUPS:                  return false;
        case FEATURE_GROUPINGS:               return false;
        case FEATURE_GROUPMEMBERSONLY:        return true;
        case FEATURE_MOD_INTRO:               return true;
        case FEATURE_COMPLETION_TRACKS_VIEWS: return true;
        case FEATURE_GRADE_HAS_GRADE:         return false;
        case FEATURE_GRADE_OUTCOMES:          return false;

        default: return null;
    }
}

/**
 * Returns all other caps used in module
 * @return array
 */
function imscp_get_extra_capabilities() {
    return array('moodle/site:accessallgroups');
}

/**
 * This function is used by the reset_course_userdata function in moodlelib.
 * @param $data the data submitted from the reset course.
 * @return array status array
 */
function imscp_reset_userdata($data) {
    return array();
}

/**
 * List of view style log actions
 * @return array
 */
function imscp_get_view_actions() {
    return array('view', 'view all');
}

/**
 * List of update style log actions
 * @return array
 */
function imscp_get_post_actions() {
    return array('update', 'add');
}

/**
 * Add imscp instance.
 * @param object $data
 * @param object $mform
 * @return int new imscp instance id
 */
function imscp_add_instance($data, $mform) {
    global $CFG, $DB;
    require_once("$CFG->dirroot/mod/imscp/locallib.php");

    $cmid = $data->coursemodule;

    $data->timemodified = time();
    $data->revision     = 1;
    $data->structure    = null;

    $data->id = $DB->insert_record('imscp', $data);

    // we need to use context now, so we need to make sure all needed info is already in db
    $DB->set_field('course_modules', 'instance', $data->id, array('id'=>$cmid));
    $context = get_context_instance(CONTEXT_MODULE, $cmid);
    $imscp = $DB->get_record('imscp', array('id'=>$data->id), '*', MUST_EXIST);

    if ($filename = $mform->get_new_filename('package')) {
        if ($package = $mform->save_stored_file('package', $context->id, 'imscp_backup', 1, '/', $filename)) {
            // extract package content
            $packer = get_file_packer('application/zip');
            $package->extract_to_storage($packer, $context->id, 'imscp_content', 1, '/');
            $structure = imscp_parse_structure($imscp, $context);
            $imscp->structure = is_array($structure) ? serialize($structure) : null;
            $DB->update_record('imscp', $imscp);
        }
    }

    return $data->id;
}

/**
 * Update imscp instance.
 * @param object $data
 * @param object $mform
 * @return bool true
 */
function imscp_update_instance($data, $mform) {
    global $CFG, $DB;
    require_once("$CFG->dirroot/mod/imscp/locallib.php");

    $cmid = $data->coursemodule;

    $data->timemodified = time();
    $data->id           = $data->instance;
    $imscp->structure   = null; // better reparse structure after each update

    $DB->update_record('imscp', $data);

    $context = get_context_instance(CONTEXT_MODULE, $cmid);
    $imscp = $DB->get_record('imscp', array('id'=>$data->id), '*', MUST_EXIST);

    if ($filename = $mform->get_new_filename('package')) {
        $fs = get_file_storage();

        $imscp->revision++;
        $DB->update_record('imscp', $imscp);

        // get a list of existing packages before adding new package
        if ($imscp->keepold > -1) {
            $packages = $fs->get_area_files($context->id, 'imscp_backup', false, "itemid ASC", false);
        } else {
            $packages = array();
        }

        $package = $mform->save_stored_file('package', $context->id, 'imscp_backup', $imscp->revision, '/', $filename);

        // purge all extracted content
        $fs->delete_area_files($context->id, 'imscp_content');

        // extract package content
        if ($package) {
            $packer = get_file_packer('application/zip');
            $package->extract_to_storage($packer, $context->id, 'imscp_content', $imscp->revision, '/');
        }

        // cleanup old package files, keep current + keepold
        while ($packages and (count($packages) > $imscp->keepold)) {
            $package = array_shift($packages);
            $fs->delete_area_files($context->id, 'imscp_backup', $package->get_itemid());
        }
    }

    $structure = imscp_parse_structure($imscp, $context);
    $imscp->structure = is_array($structure) ? serialize($structure) : null;
    $DB->update_record('imscp', $imscp);

    return true;
}

/**
 * Delete imscp instance.
 * @param int $id
 * @return bool true
 */
function imscp_delete_instance($id) {
    global $DB;

    if (!$imscp = $DB->get_record('imscp', array('id'=>$id))) {
        return false;
    }

    // note: all context files are deleted automatically

    $DB->delete_records('imscp', array('id'=>$imscp->id));

    return true;
}

/**
 * Return use outline
 * @param object $course
 * @param object $user
 * @param object $mod
 * @param object $imscp
 * @return object|null
 */
function imscp_user_outline($course, $user, $mod, $imscp) {
    global $DB;

    if ($logs = $DB->get_records('log', array('userid'=>$user->id, 'module'=>'imscp',
                                              'action'=>'view', 'info'=>$imscp->id), 'time ASC')) {

        $numviews = count($logs);
        $lastlog = array_pop($logs);

        $result = new object();
        $result->info = get_string('numviews', '', $numviews);
        $result->time = $lastlog->time;

        return $result;
    }
    return NULL;
}

/**
 * Return use complete
 * @param object $course
 * @param object $user
 * @param object $mod
 * @param object $imscp
 */
function imscp_user_complete($course, $user, $mod, $imscp) {
    global $CFG, $DB;

    if ($logs = $DB->get_records('log', array('userid'=>$user->id, 'module'=>'imscp',
                                              'action'=>'view', 'info'=>$imscp->id), 'time ASC')) {
        $numviews = count($logs);
        $lastlog = array_pop($logs);

        $strmostrecently = get_string('mostrecently');
        $strnumviews = get_string('numviews', '', $numviews);

        echo "$strnumviews - $strmostrecently ".userdate($lastlog->time);

    } else {
        print_string('neverseen', 'imscp');
    }
}

/**
 * Returns the users with data in one imscp
 *
 * @param int $imscpid
 * @return bool false
 */
function imscp_get_participants($imscpid) {
    return false;
}

/**
 * Lists all browsable file areas
 * @param object $course
 * @param object $cm
 * @param object $context
 * @return array
 */
function imscp_get_file_areas($course, $cm, $context) {
    $areas = array();
    if (has_capability('moodle/course:managefiles', $context)) {
        $areas['imscp_content'] = get_string('areacontent', 'imscp');
        $areas['imscp_backup']  = get_string('areabackup', 'imscp');
    }
    return $areas;
}

/**
 * File browsing support for imscp module ontent area.
 * @param object $browser
 * @param object $areas
 * @param object $course
 * @param object $cm
 * @param object $context
 * @param string $filearea
 * @param int $itemid
 * @param string $filepath
 * @param string $filename
 * @return object file_info instance or null if not found
 */
function imscp_get_file_info($browser, $areas, $course, $cm, $context, $filearea, $itemid, $filepath, $filename) {
    global $CFG, $DB;
    require_once("$CFG->dirroot/mod/imscp/locallib.php");

    // note: imscp_intro handled in file_browser automatically

    if (!has_capability('moodle/course:managefiles', $context)) {
        // no peaking here, sorry
        return null;
    }

    if ($filearea !== 'imscp_content' and $filearea !== 'imscp_backup') {
        return null;
    }
    if (is_null($itemid)) {
        return new imscp_file_info($browser, $course, $cm, $context, $areas, $filearea, $itemid);
    }

    $fs = get_file_storage();
    $filepath = is_null($filepath) ? '/' : $filepath;
    $filename = is_null($filename) ? '.' : $filename;
    if (!$storedfile = $fs->get_file($context->id, $filearea, $itemid, $filepath, $filename)) {
        return null;
    }

    // do not allow manual modification of any files!
    $urlbase = $CFG->wwwroot.'/pluginfile.php';
    return new file_info_stored($browser, $context, $storedfile, $urlbase, $itemid, true, true, false, false);
}

/**
 * Serves the imscp files.
 *
 * @param object $course
 * @param object $cminfo
 * @param object $context
 * @param string $filearea
 * @param array $args
 * @param bool $forcedownload
 * @return bool false if file not found, does not return if found - justsend the file
 */
function imscp_pluginfile($course, $cminfo, $context, $filearea, $args, $forcedownload) {
    global $CFG, $DB;

    if (!$cminfo->uservisible) {
        return false;
    }

    if (!$cm = get_coursemodule_from_instance('imscp', $cminfo->instance, $course->id)) {
        return false;
    }

    if ($filearea === 'imscp_content') {
        require_course_login($course, true, $cm);
        $revision = array_shift($args);
        $fs = get_file_storage();
        $relativepath = '/'.implode('/', $args);
        if ($relativepath === '/imsmanifest.xml') {
            if (!has_capability('moodle/course:managefiles', $context)) {
                // no stealing of detailed package info ;-)
                return false;
            }
        }
        $fullpath = $context->id.$filearea.$revision.$relativepath;
        if (!$file = $fs->get_file_by_hash(sha1($fullpath)) or $file->is_directory()) {
            return false;
        }

        // finally send the file
        send_stored_file($file, 86400, 0, $forcedownload);

    } else if ($filearea === 'imscp_backup') {
        require_login($course, false, $cm);
        if (!has_capability('moodle/course:managefiles', $context)) {
            // no stealing of package backups
            return false;
        }
        $revision = array_shift($args);
        $fs = get_file_storage();
        $relativepath = '/'.implode('/', $args);
        $fullpath = $context->id.$filearea.$revision.$relativepath;
        if (!$file = $fs->get_file_by_hash(sha1($fullpath)) or $file->is_directory()) {
            return false;
        }

        // finally send the file
        send_stored_file($file, 86400, 0, $forcedownload);

    } else {
        return false;
    }
}

/**
 * This function extends the global navigaiton for the site.
 * It is important to note that you should not rely on PAGE objects within this
 * body of code as there is no guarantee that during an AJAX request they are
 * available
 *
 * @param navigation_node $navigation The imscp node within the global navigation
 * @param stdClass $course The course object returned from the DB
 * @param stdClass $module The module object returned from the DB
 * @param stdClass $cm The course module isntance returned from the DB
 */
function imscp_extend_navigation($navigation, $course, $module, $cm) {
    /**
     * This is currently just a stub so that it can be easily expanded upon.
     * When expanding just remove this comment and the line below and then add
     * you content.
     */
    $navigation->nodetype = navigation_node::NODETYPE_LEAF;
}