<?php
/**
 * mysql-convert-latin1-to-utf8.php
 *
 * v1.3
 *
 * Converts incorrect MySQL latin1 columns to UTF8.
 *
 * NOTE: Look for 'TODO's for things you may need to configure.
 *
 * Documentation at:
 *  http://nicj.net/2011/04/17/mysql-converting-an-incorrect-latin1-column-to-utf8
 *
 * Or, read README.md.
 *
 * PHP Version 5
 *
 * @author    Nic Jansma <nic@nicj.net>
 * @copyright 2013 Nic Jansma
 * @link      http://www.nicj.net
 */

// TODO: Pretend-mode -- if set to true, no SQL queries will be executed.  Instead, they will only be echo'd
// to the console.
$pretend = true;

// TODO: Should SET and ENUM columns be processed?
$processEnums = false;

// TODO: The collation you want to convert the overall database to
$defaultCollation = 'utf8_unicode_ci';

// TODO Convert column collations and table defaults using this mapping
// latin1_swedish_ci is included since that's the MySQL default
$collationMap =
 array(
  'latin1_bin'        => 'utf8_bin',
  'latin1_general_ci' => 'utf8_unicode_ci',
  'latin1_swedish_ci' => 'utf8_unicode_ci',
 );

// TODO: Database information
$dbHost = 'localhost';
$dbName = '';
$dbUser = '';
$dbPass = '';

if (file_exists('config.php')) {
    require_once('config.php');
}

if ($dbPass == '') {
    echo 'DB password:';
    $dbPass = trim(fgets(STDIN));
};

$mapstring = '';
foreach ($collationMap as $s => $t) {
    $mapstring .= "'$s',";
}

// Strip trailing comma
$mapstring = substr($mapstring, 0, -1);
echo $mapstring;

// Open a connection to the information_schema database
$infoDB = new mysqli($dbHost, $dbUser, $dbPass);
$infoDB->select_db('information_schema');

// Open a second connection to the target (to be converted) database
$targetDB = new mysqli($dbHost, $dbUser, $dbPass);
$targetDB->select_db($dbName);

//
// TODO: FULLTEXT Indexes
//
// You may need to drop FULLTEXT indexes before the conversion -- execute the drop here.
// eg.
//    sqlExec($targetDB, "ALTER TABLE MyTable DROP INDEX `my_index_name`", $pretend);
//
// If so, you should restore the FULLTEXT index after the conversion -- search for 'TODO'
// later in this script.
//

// Get all tables in the specified database
$tables = sqlObjs($infoDB,
    "SELECT TABLE_NAME, TABLE_COLLATION
     FROM   TABLES
     WHERE  TABLE_SCHEMA = '$dbName'");

foreach ($tables as $table) {
    $tableName      = $table->TABLE_NAME;
    $tableCollation = $table->TABLE_COLLATION;

    // Find all columns whose collation is of one of $mapstring's source types
    $cols = sqlObjs($infoDB,
        "SELECT *
         FROM   COLUMNS
         WHERE  TABLE_SCHEMA    = '$dbName'
            AND TABLE_Name      = '$tableName'
            AND COLLATION_NAME IN($mapstring)
            AND COLLATION_NAME IS NOT NULL");

    $intermediateChanges = array();
    $finalChanges        = array();

    foreach ($cols as $col) {
        // If this column doesn't use one of the collations we want to handle, skip it
        if (!array_key_exists($col->COLLATION_NAME, $collationMap)) {
            continue;
        } else {
            $targetCollation = $collationMap[$col->COLLATION_NAME];
        }

        // Save current column settings
        $colName      = $col->COLUMN_NAME;
        $colCollation = $col->COLLATION_NAME;
        $colType      = $col->COLUMN_TYPE;
        $colDataType  = $col->DATA_TYPE;
        $colLength    = $col->CHARACTER_OCTET_LENGTH;
        $colNull      = ($col->IS_NULLABLE === 'NO') ? 'NOT NULL' : '';

        $colDefault = '';
        if ($col->COLUMN_DEFAULT !== null) {
            $colDefault = "DEFAULT '{$col->COLUMN_DEFAULT}'";
        }

        // Determine the target temporary BINARY type
        $tmpDataType = '';
        switch (strtoupper($colDataType)) {
            case 'CHAR':
                $tmpDataType = 'BINARY';
                break;

            case 'VARCHAR':
                $tmpDataType = 'VARBINARY';
                break;

            case 'TINYTEXT':
                $tmpDataType = 'TINYBLOB';
                break;

            case 'TEXT':
                $tmpDataType = 'BLOB';
                break;

            case 'MEDIUMTEXT':
                $tmpDataType = 'MEDIUMBLOB';
                break;

            case 'LONGTEXT':
                $tmpDataType = 'LONGBLOB';
                break;

            //
            // TODO: If your database uses the enum type it is safe to uncomment this block if and only if
            // all of the enum possibilities only use characters in the 0-127 ASCII character set.
            //
            case 'SET':
            case 'ENUM':
                $tmpDataType = 'SKIP';
                if ($processEnums) {
                    // ENUM data-type isn't using a temporary BINARY type -- just convert its column type directly
                    $finalChanges[] = "MODIFY `$colName` $colType COLLATE $defaultCollation $colNull $colDefault";
                }
                break;

            default:
                $tmpDataType = '';
                break;
        }

        // any data types marked as SKIP were already handled
        if ($tmpDataType === 'SKIP') {
            continue;
        }

        if ($tmpDataType === '') {
            print "Unknown type! $colDataType\n";
            exit;
        }

        // Change the column definition to the new type
        $tempColType = str_ireplace($colDataType, $tmpDataType, $colType);

        // Convert the column to the temporary BINARY cousin
        $intermediateChanges[] = "MODIFY `$colName` $tempColType $colNull";

        // Convert it back to the original type with the correct collation
        $finalChanges[] = "MODIFY `$colName` $colType COLLATE $targetCollation $colNull $colDefault";
    }

    if (array_key_exists($tableCollation, $collationMap)) {
        $finalChanges[] = 'DEFAULT COLLATE ' . $collationMap[$tableCollation];
    }

    // Now run the conversions
    if (count($intermediateChanges) > 0) {
        sqlExec($targetDB, "ALTER TABLE `$dbName`.`$tableName`\n". implode(",\n", $intermediateChanges), $pretend);
    }

    if (count($finalChanges) > 0) {
        sqlExec($targetDB, "ALTER TABLE `$dbName`.`$tableName`\n". implode(",\n", $finalChanges), $pretend);
    }
}

//
// TODO: Restore FULLTEXT indexes here
// eg.
//    sqlExec($targetDB, "ALTER TABLE MyTable ADD FULLTEXT KEY `my_index_name` (`mycol1`)", $pretend);
//

// Set the default collation
sqlExec($infoDB, "ALTER DATABASE `$dbName` COLLATE $defaultCollation", $pretend);

// Done!

//
// Functions
//
/**
 * Executes the specified SQL
 *
 * @param object  $db      Target SQL connection
 * @param string  $sql     SQL to execute
 * @param boolean $pretend Pretend mode -- if set to true, don't execute query
 *
 * @return SQL result
 */
function sqlExec($db, $sql, $pretend = false)
{
    echo "$sql;\n";
    if ($pretend === false) {
        $res = $db->query($sql); 	
	if ($res === false) {             
            $error = $db->error_list[0]['error'];     
            print "!!! ERROR: $error\n";               
        }
    }
    return $res;
}

/**
 * Gets the SQL back as objects
 *
 * @param object $db  Target SQL connection
 * @param string $sql SQL to execute
 *
 * @return SQL objects
 */
function sqlObjs($db, $sql)
{
    $res = sqlExec($db, $sql);

    $a = array();

    if ($res !== false) {
        while ($obj = $res->fetch_object()) {
            $a[] = $obj;
        }
    }

    return $a;
}

?>