<?php
/**
 * Manage specific tools.
 *
 * @todo convert into a class
 */

// Database table definitions
$table_sf = Database::get_main_table(TABLE_MAIN_SPECIFIC_FIELD);
$table_sf_val = Database::get_main_table(TABLE_MAIN_SPECIFIC_FIELD_VALUES);

/**
 * Add a specific field.
 *
 * @param string $name specific field name
 */
function add_specific_field($name)
{
    $table_sf = Database::get_main_table(TABLE_MAIN_SPECIFIC_FIELD);
    $name = trim($name);
    if (empty($name)) {
        return false;
    }
    $sql = 'INSERT INTO %s(id, code, name) VALUES(NULL, \'%s\', \'%s\')';
    $_safe_name = Database::escape_string($name);
    $_safe_code = substr($_safe_name, 0, 1);
    $_safe_code = get_specific_field_code_from_name($_safe_code);
    if (false === $_safe_code) {
        return false;
    }
    $sql = sprintf($sql, $table_sf, $_safe_code, $_safe_name);
    $result = Database::query($sql);
    if ($result) {
        return Database::insert_id();
    } else {
        return false;
    }
}

/**
 * Delete a specific field.
 *
 * @param int $id specific field id
 */
function delete_specific_field($id)
{
    $table_sf = Database::get_main_table(TABLE_MAIN_SPECIFIC_FIELD);
    $id = (int) $id;
    if (!is_numeric($id)) {
        return false;
    }
    $sql = 'DELETE FROM %s WHERE id=%s LIMIT 1';
    $sql = sprintf($sql, $table_sf, $id);
    Database::query($sql);
    //TODO also delete the corresponding values
}

/**
 * Edit a specific field.
 *
 * @param int    $id   specific field id
 * @param string $name new field name
 */
function edit_specific_field($id, $name)
{
    $table_sf = Database::get_main_table(TABLE_MAIN_SPECIFIC_FIELD);
    $id = (int) $id;
    if (!is_numeric($id)) {
        return false;
    }
    $sql = 'UPDATE %s SET name = \'%s\' WHERE id = %s LIMIT 1';
    $sql = sprintf($sql, $table_sf, $name, $id);
    Database::query($sql);
}

/**
 * @param array $conditions a list of condition (exemple : status=>STUDENT)
 * @param array $order_by   a list of fields on which to sort
 *
 * @return array An array with all specific fields, at platform level
 */
function get_specific_field_list($conditions = [], $order_by = [])
{
    $table_sf = Database::get_main_table(TABLE_MAIN_SPECIFIC_FIELD);
    $return_array = [];
    $sql = "SELECT * FROM $table_sf";
    if (count($conditions) > 0) {
        $sql .= ' WHERE ';
        $conditions_string_array = [];
        foreach ($conditions as $field => $value) {
            $conditions_string_array[] = $field.' = '.$value;
        }
        $sql .= implode(' AND ', $conditions_string_array);
    }
    if (count($order_by) > 0) {
        $sql .= ' ORDER BY '.implode(',', $order_by);
    }
    $sql_result = Database::query($sql);
    while ($result = Database::fetch_array($sql_result)) {
        $return_array[] = $result;
    }

    return $return_array;
}

/**
 * @param array $conditions a list of condition (exemple : status=>STUDENT)
 * @param array $order_by   a list of fields on which sort
 *
 * @return array an array with all users of the platform
 */
function get_specific_field_values_list(
    $conditions = [],
    $order_by = []
) {
    $table_sfv = Database::get_main_table(TABLE_MAIN_SPECIFIC_FIELD_VALUES);
    $return_array = [];
    $sql = "SELECT * FROM $table_sfv";
    if (count($conditions) > 0) {
        $sql .= ' WHERE ';

        //Fixing course id
        if (isset($conditions['c_id'])) {
            $course_info = api_get_course_info_by_id(intval($conditions['c_id']));
            $conditions['course_code'] = " '".$course_info['code']."' ";
            unset($conditions['c_id']);
        }
        //If any course_code is provided try to insert the current course code
        if (!isset($conditions['course_code'])) {
            $conditions['course_code'] = " '".api_get_course_id()."' ";
        }

        $conditions_string_array = [];
        foreach ($conditions as $field => $value) {
            $conditions_string_array[] = $field.' = '.$value;
        }
        $sql .= implode(' AND ', $conditions_string_array);
    }
    if (count($order_by) > 0) {
        $sql .= ' ORDER BY '.implode(',', $order_by);
    }
    $sql_result = Database::query($sql);
    while ($result = Database::fetch_array($sql_result)) {
        $return_array[] = $result;
    }

    return $return_array;
}

/**
 * @param string $prefix      xapian prefix
 * @param string $course_code
 * @param string $tool_id     Constant from mainapi.lib.php
 * @param int    $ref_id      representative id inside one tool item
 *
 * @return array
 */
function get_specific_field_values_list_by_prefix(
    $prefix,
    $course_code,
    $tool_id,
    $ref_id
) {
    $table_sf = Database::get_main_table(TABLE_MAIN_SPECIFIC_FIELD);
    $table_sfv = Database::get_main_table(TABLE_MAIN_SPECIFIC_FIELD_VALUES);
    $sql = 'SELECT sfv.value FROM %s sf LEFT JOIN %s sfv ON sf.id = sfv.field_id'.
        ' WHERE sf.code = \'%s\' AND sfv.c_id = \'%s\' AND tool_id = \'%s\' AND sfv.ref_id = %s';
    $sql = sprintf(
        $sql,
        $table_sf,
        $table_sfv,
        $prefix,
        $course_code,
        $tool_id,
        $ref_id
    );
    $sql_result = Database::query($sql);
    while ($result = Database::fetch_array($sql_result)) {
        $return_array[] = $result;
    }

    return $return_array;
}

/**
 * Add a specific field value.
 *
 * @param int    $id_specific_field specific field id
 * @param string $course_id         course code
 * @param string $tool_id           tool id, from main.api.lib
 * @param int    $ref_id            intern id inside specific tool table
 * @param string $value             specific field value
 */
function add_specific_field_value(
    $id_specific_field,
    $course_id,
    $tool_id,
    $ref_id,
    $value
) {
    $table_sf_values = Database::get_main_table(
        TABLE_MAIN_SPECIFIC_FIELD_VALUES
    );
    $value = trim($value);
    if (empty($value)) {
        return false;
    }
    $sql = 'INSERT INTO %s(id, course_code, tool_id, ref_id, field_id, value) VALUES(NULL, \'%s\', \'%s\', %s, %s, \'%s\')';
    $sql = sprintf(
        $sql,
        $table_sf_values,
        $course_id,
        $tool_id,
        $ref_id,
        $id_specific_field,
        Database::escape_string($value)
    );
    $result = Database::query($sql);
    if ($result) {
        return Database::insert_id();
    } else {
        return false;
    }
}

/**
 * Delete all values from a specific field id, course_id, ref_id and tool.
 *
 * @param string $course_id         course code
 * @param int    $id_specific_field specific field id
 * @param string $tool_id           tool id, from main.api.lib
 * @param int    $ref_id            intern id inside specific tool table
 */
function delete_all_specific_field_value($course_id, $id_specific_field, $tool_id, $ref_id)
{
    $table_sf_values = Database::get_main_table(TABLE_MAIN_SPECIFIC_FIELD_VALUES);
    $sql = 'DELETE FROM %s WHERE course_code = \'%s\' AND tool_id = \'%s\' AND ref_id = %s AND field_id = %s';
    $sql = sprintf($sql, $table_sf_values, $course_id, $tool_id, $ref_id, $id_specific_field);
    Database::query($sql);
}

/**
 * Delete all values from a specific item (course_id, tool_id and ref_id).
 * To be used when deleting such item from Dokeos.
 *
 * @param   string  Course code
 * @param   string  Tool ID
 * @param   int     Internal ID used in specific tool table
 */
function delete_all_values_for_item($course_id, $tool_id, $ref_id)
{
    $table_sf_values = Database::get_main_table(TABLE_MAIN_SPECIFIC_FIELD_VALUES);
    $sql = 'DELETE FROM %s WHERE course_code = \'%s\' AND tool_id = \'%s\' AND ref_id = %s';
    $sql = sprintf($sql, $table_sf_values, $course_id, $tool_id, $ref_id);
    Database::query($sql);
}

/**
 * Generates a code (one-letter string) for a given field name
 * Defaults to the first letter of the name, otherwise iterate through available
 * letters.
 *
 * @param   string  Name
 *
 * @return string One-letter code, upper-case
 */
function get_specific_field_code_from_name($name)
{
    // Z is used internally by Xapian
    // O & C already used by tool_id and course_id
    $list = [
        'A',
        'B',
        'D',
        'E',
        'F',
        'G',
        'H',
        'I',
        'J',
        'K',
        'L',
        'M',
        'N',
        'P',
        'Q',
        'R',
        'S',
        'T',
        'U',
        'V',
        'W',
        'X',
        'Y',
    ];
    $table_sf = Database::get_main_table(TABLE_MAIN_SPECIFIC_FIELD);
    $sql = "SELECT code FROM $table_sf ORDER BY code";
    $res = Database::query($sql);
    $code = strtoupper(substr($name, 0, 1));
    //if no code exists in DB, return current one
    if (Database::num_rows($res) < 1) {
        return $code;
    }

    $existing_list = [];
    while ($row = Database::fetch_array($res)) {
        $existing_list[] = $row['code'];
    }
    //if the current code doesn't exist in DB, return current one
    if (!in_array($code, $existing_list)) {
        return $code;
    }

    $idx = array_search($code, $list);
    $c = count($list);
    for ($i = $idx + 1, $j = 0; $j < $c; $i++, $j++) {
        if (!in_array($list[$i], $existing_list)) {
            return $idx[$i];
        }
    }

    // all 26 codes are used
    return false;
}
