<?php

/**

 * Plugins may load this file to gain access to special helper functions for

 * plugin installation. This file is not included by WordPress and it is

 * recommended, to prevent fatal errors, that this file is included using

 * require_once.

 *

 * These functions are not optimized for speed, but they should only be used

 * once in a while, so speed shouldn't be a concern. If it is and you are

 * needing to use these functions a lot, you might experience time outs. If you

 * do, then it is advised to just write the SQL code yourself.

 *

 *     check_column( 'wp_links', 'link_description', 'mediumtext' );

 *     if ( check_column( $wpdb->comments, 'comment_author', 'tinytext' ) ) {

 *         echo "ok\n";

 *     }

 *

 *     $error_count = 0;

 *     $tablename = $wpdb->links;

 *     // Check the column.

 *     if ( ! check_column( $wpdb->links, 'link_description', 'varchar( 255 )' ) ) {

 *         $ddl = "ALTER TABLE $wpdb->links MODIFY COLUMN link_description varchar(255) NOT NULL DEFAULT '' ";

 *         $q = $wpdb->query( $ddl );

 *     }

 *

 *     if ( check_column( $wpdb->links, 'link_description', 'varchar( 255 )' ) ) {

 *         $res .= $tablename . ' - ok <br />';

 *     } else {

 *         $res .= 'There was a problem with ' . $tablename . '<br />';

 *         ++$error_count;

 *     }

 *

 * @package WordPress

 * @subpackage Plugin

 */

/** Load WordPress Bootstrap */

require_once dirname( __DIR__ ) . '/wp-load.php';

if ( ! function_exists( 'maybe_create_table' ) ) :

	/**

	 * Creates a table in the database if it doesn't already exist.

	 *

	 * @since 1.0.0

	 *

	 * @global wpdb $wpdb WordPress database abstraction object.

	 *

	 * @param string $table_name Database table name.

	 * @param string $create_ddl SQL statement to create table.

	 * @return bool True on success or if the table already exists. False on failure.

	 */

	function maybe_create_table( $table_name, $create_ddl ) {

		global $wpdb;

		foreach ( $wpdb->get_col( 'SHOW TABLES', 0 ) as $table ) {

			if ( $table === $table_name ) {

				return true;

			}

		}

		// Didn't find it, so try to create it.

		$wpdb->query( $create_ddl );

		// We cannot directly tell that whether this succeeded!

		foreach ( $wpdb->get_col( 'SHOW TABLES', 0 ) as $table ) {

			if ( $table === $table_name ) {

				return true;

			}

		}

		return false;

	}

endif;

if ( ! function_exists( 'maybe_add_column' ) ) :

	/**

	 * Adds column to database table, if it doesn't already exist.

	 *

	 * @since 1.0.0

	 *

	 * @global wpdb $wpdb WordPress database abstraction object.

	 *

	 * @param string $table_name  Database table name.

	 * @param string $column_name Table column name.

	 * @param string $create_ddl  SQL statement to add column.

	 * @return bool True on success or if the column already exists. False on failure.

	 */

	function maybe_add_column( $table_name, $column_name, $create_ddl ) {

		global $wpdb;

		foreach ( $wpdb->get_col( "DESC $table_name", 0 ) as $column ) {

			if ( $column === $column_name ) {

				return true;

			}

		}

		// Didn't find it, so try to create it.

		$wpdb->query( $create_ddl );

		// We cannot directly tell that whether this succeeded!

		foreach ( $wpdb->get_col( "DESC $table_name", 0 ) as $column ) {

			if ( $column === $column_name ) {

				return true;

			}

		}

		return false;

	}

endif;

/**

 * Drops column from database table, if it exists.

 *

 * @since 1.0.0

 *

 * @global wpdb $wpdb WordPress database abstraction object.

 *

 * @param string $table_name  Database table name.

 * @param string $column_name Table column name.

 * @param string $drop_ddl    SQL statement to drop column.

 * @return bool True on success or if the column doesn't exist. False on failure.

 */

function maybe_drop_column( $table_name, $column_name, $drop_ddl ) {

	global $wpdb;

	foreach ( $wpdb->get_col( "DESC $table_name", 0 ) as $column ) {

		if ( $column === $column_name ) {

			// Found it, so try to drop it.

			$wpdb->query( $drop_ddl );

			// We cannot directly tell that whether this succeeded!

			foreach ( $wpdb->get_col( "DESC $table_name", 0 ) as $column ) {

				if ( $column === $column_name ) {

					return false;

				}

			}

		}

	}

	// Else didn't find it.

	return true;

}

/**

 * Checks that database table column matches the criteria.

 *

 * Uses the SQL DESC for retrieving the table info for the column. It will help

 * understand the parameters, if you do more research on what column information

 * is returned by the SQL statement. Pass in null to skip checking that

 * criteria.

 *

 * Column names returned from DESC table are case sensitive and are listed:

 *      Field

 *      Type

 *      Null

 *      Key

 *      Default

 *      Extra

 *

 * @since 1.0.0

 *

 * @global wpdb $wpdb WordPress database abstraction object.

 *

 * @param string $table_name Database table name.

 * @param string $col_name   Table column name.

 * @param string $col_type   Table column type.

 * @param bool   $is_null    Optional. Check is null.

 * @param mixed  $key        Optional. Key info.

 * @param mixed  $default    Optional. Default value.

 * @param mixed  $extra      Optional. Extra value.

 * @return bool True, if matches. False, if not matching.

 */

function check_column( $table_name, $col_name, $col_type, $is_null = null, $key = null, $default = null, $extra = null ) {

	global $wpdb;

	$diffs   = 0;

	$results = $wpdb->get_results( "DESC $table_name" );

	foreach ( $results as $row ) {

		if ( $row->Field === $col_name ) {

			// Got our column, check the params.

			if ( ( null !== $col_type ) && ( $row->Type !== $col_type ) ) {

				++$diffs;

			}

			if ( ( null !== $is_null ) && ( $row->Null !== $is_null ) ) {

				++$diffs;

			}

			if ( ( null !== $key ) && ( $row->Key !== $key ) ) {

				++$diffs;

			}

			if ( ( null !== $default ) && ( $row->Default !== $default ) ) {

				++$diffs;

			}

			if ( ( null !== $extra ) && ( $row->Extra !== $extra ) ) {

				++$diffs;

			}

			if ( $diffs > 0 ) {

				return false;

			}

			return true;

		} // End if found our column.

	}

	return false;

}