<?php
/*
* Question.inc.php
*
* This is the domain logic managing the fundamental behaviors and data of Questions.
*
* @author   Quinn Comendant <quinn@strangecode.com>
* @version  1.0
* @since    20 Aug 2014 17:20:09
*/

require_once 'models/Model.inc.php';

class Question extends Model
{
    // The database fields used by this model.
    public static $fields = array(
        'account_id' => '',
        'question_id' => '',
        'survey_id' => '',
        'rank' => 0,
        'question_text' => '',
        'auto_continue' => '',
        // 'added_datetime' => '',
        // 'added_by_user_id' => '',
        // 'modified_datetime' => '',
        // 'modified_by_user_id' => '',
    );

    /*
    *
    *
    * @access   public
    * @param
    * @return
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    16 Nov 2014 17:45:40
    */
    static public function insert($frm)
    {
        global $auth, $cache;
    	$db =& DB::getInstance();
    	$app =& App::getInstance();

        // Remove any stale cached list data.
        $cache->delete('question list');

        // Create the record under the user's account, unless an account_id was provided.
        $account_id = isset($frm['account_id']) && is_numeric($frm['account_id']) ? $frm['account_id'] : $auth->get('account_id');

        // Insert record data.
        $app->logMsg(sprintf('%s with data %s', __METHOD__, getDump($frm)), LOG_DEBUG, __FILE__, __LINE__);
        $db->query("
            INSERT INTO question_tbl (
                account_id,
                rank,
                survey_id,
                question_text,
                auto_continue,
                added_datetime,
                added_by_user_id,
                modified_datetime,
                modified_by_user_id
            ) VALUES (
                '" . $db->escapeString($account_id) . "',
                '" . $db->escapeString($frm['rank']) . "',
                '" . $db->escapeString($frm['survey_id']) . "',
                '" . $db->escapeString($frm['question_text']) . "',
                '" . (isset($frm['auto_continue']) && !empty($frm['auto_continue'])) . "',
                NOW(),
                '" . $db->escapeString($auth->get('user_id')) . "',
                NOW(),
                '" . $db->escapeString($auth->get('user_id')) . "'
            )
        ");
        $last_insert_id = mysql_insert_id($db->getDBH());

        // Process question actions.
        self::saveQuestionActions($last_insert_id, $frm);

        // Create version.
        $version = Version::getInstance($auth);
        $version->create('question_tbl', 'question_id', $last_insert_id, $frm['question_text']);

        return $last_insert_id;
    }

    /*
    *
    *
    * @access   public
    * @param
    * @return
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    16 Nov 2014 17:45:40
    */
    static public function update($frm)
    {
    	global $auth, $lock, $cache;
    	$db =& DB::getInstance();
    	$app =& App::getInstance();

        $lock->select('question_tbl', 'question_id', $frm['question_id']);
        if ($lock->isLocked() && !$lock->isMine()) {
            $lock->dieErrorPage();
        }

        // Remove any stale cached list data.
        $cache->delete('question list');

        // Create the record under the user's account, unless an account_id was provided.
        $account_id = isset($frm['account_id']) && is_numeric($frm['account_id']) ? $frm['account_id'] : $auth->get('account_id');

        // Update record data.
        $app->logMsg(sprintf('%s with data %s', __METHOD__, getDump($frm)), LOG_DEBUG, __FILE__, __LINE__);
        $db->query("
            UPDATE question_tbl SET
                account_id = '" . $db->escapeString($account_id) . "',
                question_text = '" . $db->escapeString($frm['question_text']) . "',
                auto_continue = '" . (isset($frm['auto_continue']) && !empty($frm['auto_continue'])) . "',
                modified_datetime = NOW(),
                modified_by_user_id = '" . $db->escapeString($auth->get('user_id')) . "'
            WHERE question_id = '" . $db->escapeString($frm['question_id']) . "'
        ");

        // Process question actions.
        self::saveQuestionActions($frm['question_id'], $frm);

        // Create version.
        $version = Version::getInstance($auth);
        $version->create('question_tbl', 'question_id', $frm['question_id'], $frm['question_text']);

        // Unlock record.
        $lock->remove();
    }

    /*
    *
    *
    * @access   public
    * @param
    * @return
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    16 Nov 2014 17:45:40
    */
    static public function updateRank($survey_id, $newrank)
    {
    	$db =& DB::getInstance();
    	$app =& App::getInstance();

        // Check if submitted data is valid.
        if (!isset($newrank[0][0]['question_id'])) {
            $app->logMsg(sprintf('Saving rank failed; data is not valid: %s', getDump($newrank)), LOG_ERR, __FILE__, __LINE__);
            return false;
        }

        // Check each submited value of submitted data to ensure it is the required type.
        foreach ($newrank[0] as $rank => $q) {
            if (!is_numeric($rank) || !isset($q['question_id']) || !is_numeric($q['question_id'])) {
                $app->logMsg(sprintf('Saving rank failed; invalid array element: %s => %s', $rank, getDump($q)), LOG_ERR, __FILE__, __LINE__);
                return false;
            }
        }

        // Everything looks ok, update the database.
        // We correlate with survey_id so ensure the questions being updated belong to the correct survey.
        // Add + 1 to zero-index array.
        $result = '';
        foreach ($newrank[0] as $rank => $q) {
            $rank++;
            $result[] = sprintf('%s => %s', $rank, $q['question_id']);
            $db->query("
                UPDATE question_tbl SET
                    rank = '" . $db->escapeString($rank) . "'
                WHERE question_id = '" . $db->escapeString($q['question_id']) . "'
                AND survey_id = '" . $db->escapeString($survey_id) . "'
            ");
        }

        $app->logMsg(sprintf('Saved rank for questions in survey_id %s: %s', $survey_id, join(', ', $result)), LOG_DEBUG, __FILE__, __LINE__);
        return true;
    }

    /*
    *
    *
    * @access   public
    * @param
    * @return
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    16 Nov 2014 17:45:40
    */
    static public function delete($id)
    {
        global $lock, $cache, $locally_carried_queries;
    	$db =& DB::getInstance();
    	$app =& App::getInstance();

        $lock->select('question_tbl', 'question_id', $id);
        if ($lock->isLocked() && !$lock->isMine()) {
            $lock->dieErrorPage();
        }

        // Remove any stale cached list data.
        $cache->delete('question list');

        // Delete the record.
        $db->query("DELETE FROM question_tbl WHERE question_id = '" . $db->escapeString($id) . "'");

        // Unlock record.
        $lock->remove();
    }

    /*
    *
    *
    * @access   public
    * @param
    * @return
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    16 Nov 2014 17:45:40
    */
    static public function getPaginatedList($where_clause='')
    {
        global $page, $so, $cache;
    	$db =& DB::getInstance();
    	$app =& App::getInstance();

        // Build search query if available.
        if (getFormData('q', false)) {
            $qry_words = preg_split('/[^\w]/', getFormData('q'));
            for ($i=0; $i<sizeof($qry_words); $i++) {
                $where_clause .= (empty($where_clause) ? 'WHERE' : 'AND') . "
                    (
                        question_tbl.question_text LIKE '%" . $db->escapeString($qry_words[$i]) . "%'
                    )
                ";
            }
        }

        if (getFormData('filter_survey_id', false)) {
            // Limit by filter.
            $where_clause .= (empty($where_clause) ? 'WHERE' : 'AND') . " survey_id = '" . $db->escapeString(getFormData('filter_survey_id')) . "'";
        }

        // Count the total number of records so we can do something about the page numbers.
        $qid = $db->query("
            SELECT COUNT(*)
            FROM question_tbl
            $where_clause
        ");
        list($num_results) = mysql_fetch_row($qid);

        // Set page numbers now we know (needed for next step).
        $page->setTotalItems($num_results);
        $page->calculate();

        // Final SQL, with sort and page limiters.
        $sql = "
            SELECT
                question_tbl.*,
                a1.username AS added_by_username,
                a2.username AS modified_by_username
            FROM question_tbl
            LEFT JOIN user_tbl a1 ON (question_tbl.added_by_user_id = a1.user_id)
            LEFT JOIN user_tbl a2 ON (question_tbl.modified_by_user_id = a2.user_id)
            $where_clause
            " . $so->getSortOrderSQL() . "
            " . $page->getLimitSQL() . "
        ";

        // Use a cache hash to determine if the result-set has changed.
        // A unique key for this query, with the total_items in case db records
        // were added since the last cache. This identifies a unique set of
        // cached data, but we must refer to the list that is cached by a more
        // generic name. so that we can flush the cache (if records updated)
        // without knowing the hash.
        $cache_hash = md5($sql . '|' . $page->total_items);
        $tmp_prefs = new Prefs('session', array('storagetype' => 'session'));
        if ($tmp_prefs->get('cache_hash') != $cache_hash) {
            $cache->delete('question list');
            $tmp_prefs->set('cache_hash', $cache_hash);
        }

        // First try to return from the cache.
        if ($cache->exists('question list')) {
            return $cache->get('question list');
        }

        // The list was not cached, so issue the real query.
        $qid = $db->query($sql);
        $list = array();
        while ($row = mysql_fetch_assoc($qid)) {
            $list[] = $row;
        }

        // Save this list into the cache.
        if (isset($list) && !empty($list)) {
            $cache->set('question list', $list);
        }

        return $list;
    }

    /*
    *
    *
    * @access   public
    * @param
    * @return
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    08 Nov 2013 18:48:25
    */
    static public function getListBySurvey($survey_id, $rank=0)
    {
        $db =& DB::getInstance();
        $qid = $db->query("
            SELECT question_id, question_text, rank, account_id
            FROM question_tbl
            WHERE question_tbl.survey_id = '" . $db->escapeString($survey_id) . "'
            AND rank > '" . $db->escapeString($rank) . "'
            ORDER BY question_tbl.rank ASC
        ");
        $results = array();
        while ($row = mysql_fetch_assoc($qid)) {
            $results[] = $row;
        }
        return $results;
    }

    /*
    * Save the question option actions.
    *
    * @access   public
    * @param    int     $question_id    The ID of the question.
    * @param    array   $frm            Form values submitted from the Question actions table (options, actions, targets).
    * @return   null
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    08 Nov 2013 23:44:14
    */
    static public function saveQuestionActions($question_id, $frm)
    {
        $app =& App::getInstance();
        $db =& DB::getInstance();

        if (!isset($frm['actions'])) {
            $app->logMsg(sprintf('No actions posted: %s', getDump($frm)), LOG_DEBUG, __FILE__, __LINE__);
            return false;
        }

        foreach ($frm['actions'] as $i => $a) {
            switch ($a) {
            case 'continue' :
                break;

            case 'goto' :
                $db->query("
                    REPLACE INTO question_action_tbl (
                        question_id,
                        question_option,
                        question_action,
                        target_question_id
                    ) VALUES (
                        '" . $db->escapeString($question_id) . "',
                        '" . $db->escapeString($frm['options'][$i]) . "',
                        '" . $db->escapeString($a) . "',
                        '" . $db->escapeString($frm['targets'][$i]) . "'
                    )
                ");
                break;

            case 'end' :
                $db->query("
                    REPLACE INTO question_action_tbl (
                        question_id,
                        question_option,
                        question_action,
                        target_question_id
                    ) VALUES (
                        '" . $db->escapeString($question_id) . "',
                        '" . $db->escapeString($frm['options'][$i]) . "',
                        '" . $db->escapeString($a) . "',
                        NULL
                    )
                ");
                break;

            default :
                $app->logMsg(sprintf('Unknown question action: %s', $a), LOG_ERR, __FILE__, __LINE__);
                return;
            }

            $app->logMsg(sprintf('Saved question_id %s action for option %s: %s %s', $question_id, $frm['options'][$i], $a, (isset($frm['targets'][$i]) ? $frm['targets'][$i] : '')), LOG_DEBUG, __FILE__, __LINE__);
        }
    }

    /*
    *
    *
    * @access   public
    * @param
    * @return
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    03 Nov 2013 13:31:12
    */
    static public function getParsedJSON($question_text)
    {
        $app =& App::getInstance();
        $q_parsed = self::parseOptions($question_text);
        $q_parsed_json = json_encode($q_parsed, JSON_UNESCAPED_UNICODE|JSON_PRETTY_PRINT);
        if (JSON_ERROR_NONE != json_last_error()) {
            $app->logMsg(sprintf('json_encode error: %s', json_last_error()), LOG_WARNING, __FILE__, __LINE__);
        }
        return $q_parsed_json;
    }

    /*
    * Returns the values from question_tbl for the first question in the specified survey_id.
    *
    * @access   public
    * @param    int     $survey_id
    * @return   mixed   Return value from mysql_fetch_assoc() for the query.
    * @return
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    09 Nov 2013 15:20:26
    */
    static public function getFirstInSurvey($survey_id)
    {
    	$db =& DB::getInstance();
    	$app =& App::getInstance();

        $qid = $db->query("
            SELECT *
            FROM question_tbl
            WHERE survey_id = '" . $db->escapeString($survey_id) . "'
            ORDER BY rank ASC
            LIMIT 1
        ");
        if (mysql_num_rows($qid) > 0) {
            return mysql_fetch_assoc($qid);
        } else {
            $app->logMsg(sprintf('Survey_id %s has no questions.', $survey_id), LOG_WARNING, __FILE__, __LINE__);
            return false;
        }

    }

    /*
    * Finds the question *after* the given question_id for survey_id, defined by rank.
    *
    * @access   public
    * @param    int     $question_id
    * @param    int     $survey_id
    * @return   mixed   Return value from mysql_fetch_assoc().
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    02 Nov 2013 18:53:23
    */
    static public function getNextInSurvey($question_id, $survey_id)
    {
    	$db =& DB::getInstance();

        $q = parent::get(array('question_id' => $question_id));

        // Get the question in this survey with the next-greater rank value.
        $qid = $db->query("
            SELECT question_id
            FROM question_tbl
            WHERE survey_id = '" . $db->escapeString($survey_id) . "'
            AND rank > '" . $db->escapeString($q['rank']) . "'
            ORDER BY rank ASC
            LIMIT 1
        ");
        return mysql_fetch_assoc($qid);
    }

    /*
    * Returns the values from question_action_tbl for question_id for the option provided in $response.
    * If there is no action defined for the given response, false is returned (which should be
    * interpreted as 'just continue to the next question')
    *
    * @access   public
    * @param    int     $question_id
    * @param    string  $response       The text reply sent from the participant.
    * @return   mixed   Return value from mysql_fetch_assoc().
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    09 Nov 2013 17:42:49
    */
    static public function getAction($question_id, $response)
    {
        // TODO: Need to parse $response in case either 'a' or 'the answer' is given.
        // I.e., need to do the opposite of function Question::getParsedResponse().
        $db =& DB::getInstance();

        $qid = $db->query("
            SELECT *
            FROM question_action_tbl
            WHERE question_id = '" . $db->escapeString($question_id) . "'
            AND question_option ='" . $db->escapeString(strtolower(trim($response))) . "'
        ");
        return mysql_fetch_assoc($qid);
    }

    /*
    * This function parses the question, with or without options, and returns the options as an array, or empty array for no options.
    *
    * @access   public
    * @param    string  $text   The text of the question.
    * @return   mixed           An array containing the type of question and its options; or false if the question could not be parsed.
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    02 Nov 2013 20:09:11
    */
    static public function parseOptions($text)
    {
        $app =& App::getInstance();

        $options = array();

        // Choose one only (radio).
        if (preg_match_all('/(?P<options>[A-Z])\) *(?P<labels>[\w ]+\b)[,; ]?(?!\))/ui', $text, $matches)) {
            if (count(array_unique($matches['options'])) < count($matches['options'])
            || count(array_unique($matches['labels'])) < count($matches['labels'])) {
                $app->logMsg(sprintf('Duplicate option keys or values: %s', $text), LOG_NOTICE, __FILE__, __LINE__);
                return false;
            }
            $matches['options'] = array_map('trim', $matches['options']);
            $matches['labels'] = array_map('trim', $matches['labels']);
            foreach ($matches['options'] as $i => $o) {
                if (!ctype_upper($o) || '' == $matches['labels'][$i]) {
                    // Error on non-uppercase option or empty label.
                    $app->logMsg(sprintf('Non-uppercase option or empty label: %s => %s', $o, $matches['labels'][$i]), LOG_NOTICE, __FILE__, __LINE__);
                    return false;
                }
                $options[strtolower($o)] = $matches['labels'][$i];
            }
            return array(
                'type' => 'radio',
                'text' => $text,
                'options' => $options
            );
        }

        // Choose all that apply [checkboxes].
        if (preg_match_all('/(?P<options>[A-Z])\] *(?P<labels>[\w ]+)[,; ]?(?!\])/u', $text, $matches)) {
            if (count(array_unique($matches['options'])) < count($matches['options'])
            || count(array_unique($matches['labels'])) < count($matches['labels'])) {
                return false; // Duplicate option keys or values.
            }
            foreach ($matches['options'] as $i => $o) {
                $options[strtolower($o)] = trim($matches['labels'][$i]);
            }
            return array(
                'type' => 'checkboxes',
                'text' => $text,
                'options' => $options
            );
        }

        // Open question (textfield).
        if (preg_match('/\?$/u', $text)) {
            return array(
                'type' => 'text',
                'text' => $text,
                'options' => $options
            );
        }

        // Statement (not a question)
        if (preg_match('/[\.!]$/u', $text)) {
            return array(
                'type' => 'statement',
                'text' => $text,
                'options' => $options
            );
        }

        $app->logMsg(sprintf('Question options failed parsing: %s', $text), LOG_INFO, __FILE__, __LINE__);
        return false;
    }

    /*
    * Tests if the given text response conforms with the format of the question.
    *
    * @access   public
    * @param    int     $question_id        The ID of the question
    * @param    string  $response_text      The Body received from the SMS.
    * @return   bool                        True of it matches, false otherwise.
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    02 Nov 2013 20:06:11
    */
    static public function validateResponse($question_id, $response_text)
    {
        $app =& App::getInstance();

        $q = parent::get(array('question_id' => $question_id));
        $q_parsed = self::parseOptions($q['question_text']);

        if ('' == trim($response_text)) {
            $app->logMsg(sprintf('Received empty response.', null), LOG_INFO, __FILE__, __LINE__);
            return false;
        }

        if ('statement' == $q_parsed['type']) {
            // Statements should not receive a response.
            $app->logMsg(sprintf('Received a response to a statement.', null), LOG_NOTICE, __FILE__, __LINE__);
            return false;
        }

        if ('text' == $q_parsed['type']) {
            // Any response value is a valid response.
            return true;
        }

        $q_parsed_options_lowercase = array_map('strtolower', $q_parsed['options']);

        if ('radio' == $q_parsed['type']
        && (isset($q_parsed['options'][strtolower(trim($response_text))])
        || in_array(strtolower(trim($response_text)), $q_parsed_options_lowercase))
        ) {
            // The response value matches one of the options
            return true;
        }

        if ('checkboxes' == $q_parsed['type']) {
            $return = 0;
            $response_array = array_diff(preg_split('/[\W -]/', $response_text), array(''));
            foreach ($response_array as $v) {
                if (isset($q_parsed['options'][strtolower(trim($v))]) || in_array(strtolower(trim($v)), $q_parsed_options_lowercase)) {
                    $return++;
                } else {
                    $return--;
                }
            }
            // The response had some unmatched values. :(
            return $return == sizeof($response_array);
        }

        return false;
    }

    /*
    * Returns the parsed value of a response (i.e. instead of "A" it returns "The option text")
    *
    * @access   public
    * @param    int     $question_id        The ID of the question
    * @param    string  $response_text      The Body received from the SMS.
    * @return   string                      A human-readable value for the response.
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    02 Nov 2013 20:06:11
    */
    static public function getParsedResponse($question_id, $response_text)
    {
        $app =& App::getInstance();

        $q = parent::get(array('question_id' => $question_id));
        $q_parsed = self::parseOptions($q['question_text']);

        if ('' == trim($response_text) || !$q_parsed['type']) {
            $app->logMsg(sprintf('Response was empty or failed to parse question text "%s"', $q['question_text']), LOG_DEBUG, __FILE__, __LINE__);
            return false;
        }

        if ('statement' == $q_parsed['type']) {
            // There shouldn't be any response.
            return $response_text;
        }

        if ('text' == $q_parsed['type']) {
            // Any response value is a valid response.
            return $response_text;
        }

        $q_parsed_options_lowercase = array_map('strtolower', $q_parsed['options']);

        if ('radio' == $q_parsed['type']) {
            if (isset($q_parsed['options'][strtolower(trim($response_text))])) {
                // The response value matches one of the options.
                return $q_parsed['options'][strtolower(trim($response_text))];
            } else if (false !== ($key_of_match = array_search(strtolower(trim($response_text)), $q_parsed_options_lowercase))) {
                // The response value matches one of the labels.
                return $q_parsed['options'][$key_of_match];
            }
        }

        if ('checkboxes' == $q_parsed['type']) {
            $return = array();
            $response_array = array_diff(preg_split('/[\W -]/', $response_text), array(''));
            foreach ($response_array as $v) {
                if (isset($q_parsed['options'][strtolower(trim($v))])) {
                    // The response value matches one of the options.
                    $return[] = $q_parsed['options'][strtolower(trim($v))];
                } else if (false !== ($key_of_match = array_search(strtolower(trim($v)), $q_parsed_options_lowercase))) {
                    // The response value matches one of the labels.
                    $return[] = $q_parsed['options'][$key_of_match];
                }
            }
            if (!empty($return)) {
                // Return only if we found something.
                return join(', ', $return);
            }
        }

        $app->logMsg(sprintf('Failed to get parsed response for question %s: %s', $question_id, $response_text), LOG_WARNING, __FILE__, __LINE__);
        return false;
    }

    /*
    * Returns an array of question statistics.
    *
    * @access   public
    * @param    int     $question_id
    * @return   mixed       The result from mysql_fetch_assoc() for the query.
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    10 Nov 2013 14:33:17
    */
    static public function getStats($question_id)
    {
        $db =& DB::getInstance();
        $qid = $db->query("
            SELECT (
                SELECT COUNT(*)
                FROM response_tbl
                WHERE question_id = '" . $db->escapeString($question_id) . "'
            ) AS num_responses, (
                SELECT ROUND((num_responses / COUNT(*)) * 100, 2)
                FROM question_tbl
                LEFT JOIN participant_survey_tbl ON (question_tbl.survey_id = participant_survey_tbl.survey_id)
                WHERE question_id = '" . $db->escapeString($question_id) . "'
            ) AS percent_of_participants
        ");
        return mysql_fetch_assoc($qid);
    }

}