<?php

/**
 * Very stable interface for MySQL - object-oriented at last :)
 * Select builder is inspired by MediaWiki's one.
 * Also usable for querying SphinxQL.
 * Version: 2015-05-13
 * (c) Vitaliy Filippov, 2012-2015
 */

if (!defined('MS_HASH'))
{
    define('MS_HASH', 0);
    define('MS_LIST', 1);
    define('MS_ROW', 2);
    define('MS_ONE', 2);
    define('MS_COL', 4);
    define('MS_VALUE', 6);
    define('MS_RESULT', 8);
}

class DatabaseException extends Exception
{
    function isDuplicateKey()
    {
        return $this->getCode() == 1062;
    }
}

if (!interface_exists('Database'))
{
    interface Database {}
}

class DatabaseMysql implements Database
{
    var $host, $port, $socket, $username, $password, $dbname;

    var $tableNames = array();
    var $queryLogFile, $loggedQueries = '';
    var $reconnect = true;
    var $autoBegin;
    var $ondestroy = 'commit';

    var $queryCount = 0;
    var $link;
    var $transactions = array();

    /**
     * Creates a MySQL connection object.
     *
     * @param array $options Possible options:
     *     host         Host name or IP address to connect to   [localhost]
     *     socket       Path to UNIX socket to connect to       [/var/run/mysqld/mysqld.sock]
     *     port         TCP port to connect to                  [3306]
     *     dbname       DB name to use
     *     username     Username
     *     password     Password
     *     tableNames   Table name mappings (virtual => real)
     *     queryLogFile Path to query log file
     *     reconnect    Whether to reconnect on idle timeout    [true]
     *     autoBegin    Whether to automatically begin a transaction of first query [false]
     *     ondestroy    commit/rollback/none during destruction [commit]
     */
    function __construct($options)
    {
        $defOpts = array(
            'host' => 'localhost',
            'port' => 3306,
            'socket' => '/var/run/mysqld/mysqld.sock',
            'dbname' => '',
            'username' => '',
            'password' => '',
            'reconnect' => true,
            'tableNames' => array(),
            'queryLogFile' => '',
            'autoBegin' => false,
            'ondestroy' => 'commit',
        );
        $options += $defOpts;
        if ($options['socket'])
        {
            $options['host'] = 'localhost';
        }
        foreach ($defOpts as $k => $v)
        {
            $this->$k = $options[$k];
        }
    }

    function __destruct()
    {
        $o = $this->ondestroy;
        if (($o === 'commit' || $o === 'rollback') && $this->transactions)
        {
            $this->transactions = array(false);
            $this->$o();
        }
        if ($this->queryLogFile)
        {
            file_put_contents($this->queryLogFile, $this->loggedQueries, FILE_APPEND);
        }
    }

    function connect()
    {
        if ($this->socket !== NULL)
        {
            $this->link = new mysqli($this->host, $this->username, $this->password, $this->dbname, $this->port, $this->socket);
        }
        elseif ($this->port !== NULL)
        {
            $this->link = new mysqli($this->host, $this->username, $this->password, $this->dbname, $this->port);
        }
        else
        {
            $this->link = new mysqli($this->host, $this->username, $this->password, $this->dbname);
        }
        $errno = $this->link->connect_errno;
        $error = $this->link->connect_error;
        if ($errno)
        {
            $this->link = NULL;
            throw new DatabaseException($error, $errno);
        }
        else
        {
            $this->transactions = array();
            $this->link->set_charset('utf8');
            if ($this->username || $this->dbname) // skip for Sphinx
            {
                // READ COMMITTED is more consistent for average usage
                $this->link->query('SET SESSION TRANSACTION ISOLATION LEVEL READ COMMITTED');
            }
            if ($this->autoBegin)
            {
                $this->begin();
            }
        }
    }

    function getDBName()
    {
        return $this->dbname;
    }

    function quoteId($name)
    {
        return "`".str_replace("`", "``", $name)."`";
    }

    function quoteInto($str, $params)
    {
        $i = 0;
        $r = '';
        while (($p = strpos($str, '?')) !== false)
        {
            $r .= substr($str, 0, $p) . $this->quote($params[$i++]);
            $str = substr($str, $p+1);
        }
        return $r.$str;
    }

    function quote($value)
    {
        if ($value === NULL)
        {
            return "NULL";
        }
        if (!$this->link)
        {
            $this->connect();
        }
        return "'" . $this->link->real_escape_string($value) . "'";
    }

    function query($sql, $fetchMode = MYSQLI_STORE_RESULT)
    {
        if (!$this->link)
        {
            $this->connect();
        }
        $this->queryCount++;
        if ($this->queryLogFile)
        {
            $begin = explode(' ', microtime(), 2);
        }
        $r = $this->link->query($sql, $fetchMode);
        if ($this->queryLogFile)
        {
            $end = explode(' ', microtime(), 2);
            $this->loggedQueries .= date("[Y-m-d H:i:s.").substr($end[0], 2, 6)."] [".
                sprintf("%.05fs", $end[1]-$begin[1]+$end[0]-$begin[0])."] $sql\n";
        }
        if (!$r)
        {
            if ($this->link->errno == 2006 && $this->reconnect && !$this->transactions)
            {
                // "MySQL server has gone away"
                $this->connect();
                $r = $this->link->query($sql, $fetchMode);
                if (!$r && $this->link->errno == 2006)
                {
                    $this->link = false;
                }
            }
            if (!$r)
            {
                throw new DatabaseException($this->link->error . "\nQuery: $sql", $this->link->errno);
            }
        }
        return $r;
    }

    function multi_select(array $queries, $format = 0)
    {
        if (!$this->link)
        {
            $this->connect();
        }
        $this->queryCount += count($queries);
        $log = '';
        foreach ($queries as &$sql)
        {
            if (!is_string($sql))
            {
                $sql = $this->select_builder($sql[0], $sql[1], $sql[2], @$sql[3]);
            }
            $log .= date("[Y-m-d H:i:s] ").$sql."\n";
        }
        unset($sql);
        if ($this->queryLogFile)
        {
            file_put_contents($this->queryLogFile, $log, FILE_APPEND);
        }
        $sql = implode('; ', $queries);
        $r = $this->link->multi_query($sql);
        if (!$r)
        {
            if ($this->link->errno == 2006 && $this->reconnect && !$this->transactions)
            {
                // "MySQL server has gone away"
                $this->connect();
                $r = $this->link->multi_query($sql);
                if (!$r && $this->link->errno == 2006)
                {
                    $this->link = false;
                }
            }
            if (!$r)
            {
                throw new DatabaseException($this->link->error, $this->link->errno);
            }
        }
        $results = array();
        $i = 0;
        foreach ($queries as $k => $q)
        {
            if ($i++)
            {
                $this->link->next_result();
            }
            $r = $this->link->store_result();
            $results[$k] = $this->fetch_all($r, $format);
        }
        return $results;
    }

    /**
     * Starts a transaction, supports nested calls and savepoints.
     * @param boolean $savepoint Creates savepoints only this parameter is true.
     */
    function begin($savepoint = false)
    {
        $this->transactions[] = $savepoint;
        $n = count($this->transactions);
        if ($n == 1)
        {
            return $this->query("BEGIN");
        }
        elseif ($savepoint)
        {
            return $this->query("SAVEPOINT sp$n");
        }
        return true;
    }

    /**
     * Commits transaction or releases last savepoint.
     * If there is no last savepoint, just returns true.
     */
    function commit()
    {
        $savepoint = array_pop($this->transactions);
        if (!$this->transactions)
        {
            return $this->query("COMMIT");
        }
        elseif ($savepoint)
        {
            return $this->query("RELEASE SAVEPOINT sp".(1+count($this->transactions)));
        }
        return true;
    }

    /**
     * Rollbacks transaction or last savepoint.
     * If there is no savepoint, returns false.
     */
    function rollback()
    {
        $savepoint = array_pop($this->transactions);
        if (!$this->transactions)
        {
            return $this->query("ROLLBACK");
        }
        elseif ($savepoint)
        {
            return $this->query("ROLLBACK TO SAVEPOINT sp".(1+count($this->transactions)));
        }
        return false;
    }

    function errno()
    {
        return $this->link->errno;
    }

    function error()
    {
        return $this->link->error;
    }

    /**
     * Builds WHERE-part of an SQL query.
     * $where can also be a string - then it's passed as-is.
     *
     * @param array $where Query conditions:
     *   array(
     *     'conditional expression',
     *     'field_name' => 'value',
     *     'field_name' => array('one', 'of', 'values'),
     *     'field_name < ?' => 'value',
     *     'field_name < DATE_SUB(?, ?)' => array('arg1', 'arg2'),
     *     'field1,field2' => array(array(1, 2), array(3, 4)),
     *   )
     */
    function where_builder($where)
    {
        if (!is_array($where))
            return $where;
        $wh = array();
        foreach ($where as $k => $v)
        {
            if (ctype_digit("$k"))
            {
                if (is_array($v))
                {
                    $str = array_shift($v);
                    $wh[] = $this->quoteInto($str, $v);
                }
                else
                {
                    $wh[] = $v;
                }
            }
            elseif (($p = strrpos($k, '?')) !== false)
            {
                $wh[] = $this->quoteInto($k, (array)$v);
            }
            elseif (is_array($v))
            {
                if (!$v)
                {
                    // FIXME: It seems we should return empty result in that case
                    throw new DatabaseException("Error: empty array for '$k IN (...)', don't know what to do");
                }
                else
                {
                    if (is_array(reset($v)))
                    {
                        // (a,b) IN ((1,2), (3,4)) ...
                        foreach ($v as &$l)
                        {
                            $l = "(" . implode(",", array_map(array($this, 'quote'), $l)) . ")";
                        }
                        $wh[] = "$k IN (" . implode(",", $v) . ")";
                    }
                    else
                    {
                        $r = '';
                        $null = false;
                        foreach ($v as $i => $l)
                        {
                            if ($l === NULL)
                            {
                                $null = true;
                            }
                            else
                            {
                                $r .= $this->quote($l).',';
                            }
                        }
                        $r = $r !== '' ? "$k IN (" . substr($r, 0, -1) . ")" : '';
                        if ($null)
                        {
                            $r = $r !== '' ? "($r OR $k IS NULL)" : "$k IS NULL";
                        }
                        $wh[] = $r;
                    }
                }
            }
            elseif (preg_match('/^-?\d+(\.\d+)?$/s', $v)) // int/float
                $wh[] = "$k=$v";
            elseif ($v !== NULL)
                $wh[] = "$k=".$this->quote($v);
            else
                $wh[] = "$k IS NULL";
        }
        if (!$this->username && !$this->password && !$this->dbname)
        {
            // Sphinx supports neither brackets nor OR operator as of 2.0.6-release O_o
            $where = join(' AND ', $wh);
        }
        elseif ($where)
            $where = '(' . join(') AND (', $wh) . ')';
        else
            $where = '';
        return $where;
    }

    /**
     * Builds SQL query text.
     *
     * @param mixed $tables see $this->tablesBuilder()
     * @param mixed $fields Field definitions - either a string or an array.
     *   Strings are passed to resulting query text as-is.
     *   Arrays have the following format:
     *   array('field1', 'alias2' => 'expression2', ...)
     * @param mixed $where see $this->whereBuilder()
     * @param array $options query options - array of:
     *   'CALC_FOUND_ROWS'
     *   'NO_CACHE' or 'CACHE'
     *   'FOR UPDATE' or 'LOCK IN SHARE MODE'
     *   'GROUP BY' => array($groupby_field1 => 'ASC', $groupby_field2 => 'DESC')
     *   'ORDER BY' => array($orderby_field1 => 'ASC', $orderby_field2 => 'DESC')
     *   'LIMIT' => array($offset, $limit) or array($limit) or just $limit
     *   'OFFSET' => $offset, for the case when 'LIMIT' is just $limit
     *
     *   Sphinx Search extensions:
     *   'WITHIN GROUP ORDER BY' => array($orderby_field => 'ASC')
     *   'FIELD_WEIGHTS' => array('field' => <weight>, ...)
     *   'RANKER' => bm25|sph04|...|expr('...ranker expression...')
     */
    function select_builder($tables, $fields, $where, $options = NULL)
    {
        if (!$options)
            $options = array();
        else
        {
            foreach ($options as $k => $v)
                if (ctype_digit("$k"))
                    $options[$v] = true;
        }
        if (is_array($fields))
        {
            foreach ($fields as $k => $v)
                if (!ctype_digit("$k"))
                    $fields[$k] = "$v AS ".$this->quoteId($k);
            $fields = join(',', $fields);
        }
        $where = $this->where_builder($where);
        $tables = $this->tables_builder($tables);
        $sql = 'SELECT ';
        if (isset($options['CALC_FOUND_ROWS']) || isset($options['SQL_CALC_FOUND_ROWS']))
            $sql .= 'SQL_CALC_FOUND_ROWS ';
        if (isset($options['NO_CACHE']) || isset($options['SQL_NO_CACHE']))
            $sql .= 'SQL_NO_CACHE ';
        elseif (isset($options['CACHE']) || isset($options['SQL_CACHE']))
            $sql .= 'SQL_CACHE ';
        $sql .= "$fields FROM $tables";
        if ($where)
        {
            $sql .= " WHERE $where";
        }
        if (!empty($options['GROUP BY']) && $options['GROUP BY'] !== '0')
        {
            $sql .= " GROUP BY ".$this->order_option($options['GROUP BY']);
        }
        if (!empty($options['ORDER BY']) && $options['ORDER BY'] !== '0')
        {
            $sql .= " ORDER BY ".$this->order_option($options['ORDER BY']);
        }
        if (!empty($options['WITHIN GROUP ORDER BY']) && $options['WITHIN GROUP GROUP BY'] !== '0')
        {
            // Sphinx Search extension
            $sql .= " WITHIN GROUP ORDER BY ".$this->order_option($options['WITHIN GROUP ORDER BY']);
        }
        $sql .= $this->limit_option($options);
        if (!empty($options['FIELD_WEIGHTS']) || !empty($options['RANKER']))
        {
            // Sphinx Search extension
            $opt = array();
            if (!empty($options['FIELD_WEIGHTS']))
            {
                $weights = array();
                foreach ($options['FIELD_WEIGHTS'] as $f => $w)
                {
                    $weights[] = "`$f`=$w";
                }
                $opt[] = "field_weights=(".implode(', ', $weights).")";
            }
            if (!empty($options['RANKER']))
            {
                $opt[] = "ranker=".$options['RANKER'];
            }
            $sql .= " OPTION ".implode(', ', $opt);
        }
        if (isset($options['FOR UPDATE']))
            $sql .= ' FOR UPDATE';
        elseif (isset($options['LOCK IN SHARE MODE']))
            $sql .= ' LOCK IN SHARE MODE';
        return $sql;
    }

    /**
     * Handles ORDER BY or GROUP BY options
     */
    protected function order_option($g)
    {
        if (is_array($g))
        {
            $g1 = array();
            foreach ($g as $k => $v)
            {
                if (ctype_digit("$k"))
                    $g1[] = $v;
                else
                    $g1[] = "$k $v";
            }
            $g = join(',', $g1);
        }
        return $g;
    }

    /**
     * Handles a single LIMIT or LIMIT and OFFSET options.
     */
    protected function limit_option($options)
    {
        if (isset($options['LIMIT']))
        {
            $g = $options['LIMIT'];
            if (is_array($g))
                $g = join(',', $g);
            elseif ($g && isset($options['OFFSET']))
                $g = "$options[OFFSET], $g";
            if ($g)
                return " LIMIT $g";
        }
        return '';
    }

    /**
     * Builds FROM-part of an SQL query.
     *
     * $tables = array(
     *   'table',
     *   'alias' => 'table',
     *   'alias' => array('INNER', 'table_name', $where_for_on_clause),
     *   'alias' => array('INNER', $nested_tables),
     * )
     * or just a string "`table1` INNER JOIN `table2` ON ..."
     * names taken into `backticks` will be transformed using $this->tableNames
     */
    function tables_builder($tables)
    {
        if (is_array($tables))
        {
            $t = '';
            foreach ($tables as $k => $v)
            {
                if (!ctype_digit("$k"))
                {
                    if (is_array($v))
                    {
                        $join = strtolower(substr($v[0], 0, 4));
                        if ($join == 'righ')
                            $join = 'RIGHT';
                        elseif ($join == 'left')
                            $join = 'LEFT';
                        else /* if (!$join || $join == 'inne' || $join == 'join') */
                            $join = 'INNER';
                        if (is_array($v[1])) // nested join (left join (A join B on ...) on ...)
                            $table = '('.$this->tables_builder($v[1]).')';
                        else
                            $table = (isset($this->tableNames[$v[1]]) ? $this->quoteId($this->tableNames[$v[1]]) : $v[1]) . ' ' . $k;
                        if ($t)
                            $t .= " $join JOIN $table ON ".($this->where_builder($v[2]) ?: '1=1');
                        else
                            $t = $table;
                        continue;
                    }
                    else
                        $v = (isset($this->tableNames[$v]) ? $this->quoteId($this->tableNames[$v]) : $v) . ' ' . $k;
                }
                else
                    $v = (isset($this->tableNames[$v]) ? $this->quoteId($this->tableNames[$v]).' '.$v : $v);
                if ($t)
                    $t .= " INNER JOIN $v";
                else
                    $t = $v;
            }
            $tables = $t;
        }
        else
            $tables = preg_replace_callback('/((?:,|JOIN)\s*`)([^`]+)/s', array($this, 'tables_builder_pregcb1'), $tables);
        return $tables;
    }

    function tables_builder_pregcb1($m)
    {
        if (isset($this->tableNames[$m[2]]))
            return $m[1].$this->tableNames[$m[2]];
        return $m[1].$m[2];
    }

    /**
     * Run a SELECT query and return results.
     *
     * Usage: either
     * $this->select($tables, $fields, $where, $options, $format)
     *   using $this->select_builder() or
     * $this->select($sql_text, $format)
     *   using query text.
     *
     * @param int $format Return format, bitmask of MS_XX constants:
     *   MS_RESULT = return mysqli result object to manually fetch from
     *   MS_LIST   = return rows as indexed arrays
     *   MS_HASH   = return rows as associative arrays (default)
     *   MS_ROW    = only return the first row
     *   MS_COL    = only return the first column
     *   MS_VALUE  = only return the first cell (just 1 value)
     */
    function select($tables, $fields = '*', $where = 1, $options = NULL, $format = 0)
    {
        if (is_int($fields))
        {
            $sql = $tables;
            $format = $fields;
        }
        else
            $sql = $this->select_builder($tables, $fields, $where, $options);
        if ($format & MS_RESULT)
            return $this->query($sql, MYSQLI_USE_RESULT);
        $res = $this->query($sql);
        return $this->fetch_all($res, $format);
    }

    function fetch_all($res, $format = 0)
    {
        if ($format & MS_LIST)
            $r = $this->get_rows($res);
        else
            $r = $this->get_assocs($res);
        if (!$r)
            $r = array();
        if ($format & MS_ROW)
        {
            if (!count($r))
                return NULL;
            if ($format & MS_COL)
            {
                $r = $r[0];
                $k = array_keys($r);
                $r = $r[$k[0]];
            }
            else
                $r = $r[0];
        }
        elseif ($format & MS_COL)
        {
            $k = false;
            foreach ($r as $i => $v)
            {
                if (!$k)
                {
                    $k = array_keys($v);
                    $k = $k[0];
                }
                $r[$i] = $v[$k];
            }
        }
        return $r;
    }

    function found_rows()
    {
        return $this->select('SELECT FOUND_ROWS()', MS_VALUE);
    }

    /**
     * Delete a set of rows.
     * @param mixed $tables see $this->tables_builder()
     * @param mixed $where see $this->where_builder()
     * @param array $options Options for query:
     *   'LIMIT' => array($limit, $offset) or array($limit) or just $limit
     *   'OFFSET' => $offset, for the case when 'LIMIT' is just $limit
     */
    function delete($tables, $where, $options = NULL)
    {
        $tables = $this->tables_builder($tables);
        $where = $this->where_builder($where) ?: '1=1';
        $sql = "DELETE FROM $tables WHERE $where";
        $sql .= $this->limit_option($options);
        $this->query($sql);
        return $this->link->affected_rows;
    }

    /**
     * Builds an INSERT query.
     * @param string $table Table name to insert rows to.
     * @param array $rows Array of table rows to be inserted.
     * @param boolean $onduplicatekey If true, create MySQL-specific "UPSERT" query using
     *   INSERT .. ON DUPLICATE KEY UPDATE column=VALUES(column) for all columns.
     * @param boolean $replace If true, use REPLACE instead of INSERT
     */
    function insert_builder($table, $rows, $onduplicatekey = false, $replace = false)
    {
        if (isset($this->tableNames[$table]))
        {
            $table = $this->tableNames[$table];
        }
        $key = array_keys($rows[0]);
        foreach ($rows as &$r)
        {
            $rs = array();
            foreach ($key as &$k)
                $rs[] = $this->quote($r[$k]);
            $r = "(".implode(",", $rs).")";
        }
        $sphinx = !$this->username && !$this->password && !$this->dbname;
        foreach ($key as &$k)
            if (strpos($k, '`') === false && (!$sphinx || $k !== 'id'))
                $k = $this->quoteId($k);
        $sql = ($replace ? "REPLACE" : "INSERT").
            " INTO $table (".implode(",",$key).") VALUES ".implode(",",$rows);
        if ($onduplicatekey)
        {
            foreach ($key as &$k)
                $k = "$k=VALUES($k)";
            $sql .= " ON DUPLICATE KEY UPDATE ".implode(",",$key);
        }
        return $sql;
    }

    /**
     * Insert a single row into $table and return inserted ID.
     * @param string $table Table name to insert row to.
     * @param array $rows Row to be inserted.
     * @return int $insert_id Autoincrement ID of inserted row (if appropriate).
     */
    function insert_row($table, $row)
    {
        $sql = $this->insert_builder($table, array($row));
        if ($this->query($sql))
            return $this->link->insert_id;
        return NULL;
    }

    function insert_id()
    {
        return $this->link->insert_id;
    }

    /**
     * Update or insert rows into $table.
     * Update query: $this->update($table, $set, $where, $options);
     * Insert-or-update query: $this->update($table, $rows);
     *
     * @param string $table Table name to update.
     * @param array $rows One row or array of rows for insert-or-update query.
     * @param array $set Assoc array with values for update query.
     * @param array $where Conditions for update query, see $this->where_builder().
     * @param array $options Options for update query:
     *   'LIMIT' => array($limit, $offset) or array($limit) or just $limit
     *   'OFFSET' => $offset, for the case when 'LIMIT' is just $limit
     *   'REPLACE' => true to use REPLACE instead of INSERT
     */
    function update($table, $rows, $where = NULL, $options = NULL)
    {
        if (!$rows)
            return false;
        if (is_null($where))
        {
            if (!is_array($rows))
                return false;
            if (!is_array(@$rows[0]))
                $rows = array($rows);
            $sql = $this->insert_builder($table, $rows, empty($options['REPLACE']), !empty($options['REPLACE']));
        }
        else
        {
            $sql = array();
            foreach ((array)$rows as $k => $v)
            {
                if (!ctype_digit("$k"))
                    $sql[] = $k.'='.$this->quote($v);
                else
                    $sql[] = $v;
            }
            $where = $this->where_builder($where) ?: '1=1';
            $sql = 'UPDATE ' . $this->tables_builder($table) . ' SET ' . implode(', ', $sql) . ' WHERE ' . $where;
            $sql .= $this->limit_option($options);
        }
        if ($this->query($sql))
            return $this->link->affected_rows;
        return false;
    }

    function replace($table, $rows, $where = NULL, $options = array())
    {
        $options['REPLACE'] = true;
        return $this->update($table, $rows, $where, $options);
    }

    protected function get_rows($res)
    {
        $r = array();
        if ($res)
        {
            while ($row = $res->fetch_row())
                $r[] = $row;
            $res->free();
        }
        return $r;
    }

    protected function get_assocs($res)
    {
        $r = array();
        if ($res)
        {
            while ($row = $res->fetch_assoc())
                $r[] = $row;
            $res->free();
        }
        return $r;
    }
}