Proyectos de Subversion Moodle

<?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/>.

declare(strict_types=1);

namespace core_reportbuilder\local\aggregation;

use lang_string;

use core_reportbuilder\local\report\column;

/**

 * Base class for column aggregation types

 *

 * @package     core_reportbuilder

 * @copyright   2021 Paul Holden <paulh@moodle.com>

 * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

abstract class base {

    /**

     * Return the class name of the aggregation type

     *

     * @return string

     */

    final public static function get_class_name(): string {

        $namespacedclass = explode('\\', get_called_class());

        return end($namespacedclass);

    }

    /**

     * Return the display name of the aggregation

     *

     * @return lang_string

     */

    abstract public static function get_name(): lang_string;

    /**

     * Whether the aggregation is compatible with the given column type

     *

     * @param int $columntype The type as defined by the {@see column::set_type} method

     * @return bool

     */

    abstract public static function compatible(int $columntype): bool;

    /**

     * Whether the aggregation is sortable, by default return the sortable status of the column itself

     *

     * @param bool $columnsortable

     * @return bool

     */

    public static function sortable(bool $columnsortable): bool {

        return $columnsortable;

    }

    /**

     * Return SQL suitable for using within {@see get_field_sql} for column fields, by default just the first one

     *

     * @param string[] $sqlfields

     * @return string

     */

    public static function get_column_field_sql(array $sqlfields): string {

        return reset($sqlfields);

    }

    /**

     * Helper method for concatenating given fields for a column, so they are suitable for aggregation

     *

     * @param string[] $sqlfields

     * @param string $delimeter

     * @param string $coalescechar

     * @return string

     */

    final protected static function get_column_fields_concat(

        array $sqlfields,

        string $delimeter = ',',

        string $coalescechar = ' '

    ): string {

        global $DB;

        // We need to ensure all values are char.

        $sqlfieldrequirescast = in_array($DB->get_dbfamily(), ['mssql', 'oracle', 'postgres']);

        $concatfields = [];

        foreach ($sqlfields as $sqlfield) {

            if ($sqlfieldrequirescast) {

                $sqlfield = $DB->sql_cast_to_char($sqlfield);

            }

            // Coalesce all the SQL fields. Ensure cross-DB compatibility, and that we always get string data back.

            $concatfields[] = "COALESCE({$sqlfield}, '{$coalescechar}')";

            $concatfields[] = "'{$delimeter}'";

        }

        // Slice off the last delimeter.

        return $DB->sql_concat(...array_slice($concatfields, 0, -1));

    }

    /**

     * Return the aggregated field SQL

     *

     * @param string $field

     * @param int $columntype

     * @return string

     */

    abstract public static function get_field_sql(string $field, int $columntype): string;

    /**

     * Return formatted value for column when applying aggregation, by default executing all callbacks on the value

     *

     * Should be overridden in child classes that need to format the column value differently (e.g. 'sum' would just show

     * a numeric count value)

     *

     * @param mixed $value

     * @param array $values

     * @param array $callbacks Array of column callbacks, {@see column::add_callback} for definition

     * @param int $columntype The original type of the column, to ensure it is preserved for callbacks

     * @return mixed

     */

    public static function format_value($value, array $values, array $callbacks, int $columntype) {

        foreach ($callbacks as $callback) {

            [$callable, $arguments] = $callback;

            $value = ($callable)($value, (object) $values, $arguments, static::get_class_name());

        }

        return $value;

    }

}