<?php

# Copyright (c) 2009-2015 Yubico AB
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
#   * Redistributions of source code must retain the above copyright
#     notice, this list of conditions and the following disclaimer.
#
#   * Redistributions in binary form must reproduce the above
#     copyright notice, this list of conditions and the following
#     disclaimer in the documentation and/or other materials provided
#     with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

/**
 * Class for managing database connection
 */

require_once('ykval-log.php');

abstract class Db
{
    /**
     * static function to determine database type and instantiate the correct subclass
     *
     * */
    public static function GetDatabaseHandle($baseParams, $logname)
    {
        if(substr($baseParams['__YKVAL_DB_DSN__'], 0, 3) == 'oci') {
            require_once 'ykval-db-oci.php';
        } else {
            require_once 'ykval-db-pdo.php';
        }
        return new DbImpl($baseParams['__YKVAL_DB_DSN__'],
                          $baseParams['__YKVAL_DB_USER__'],
                          $baseParams['__YKVAL_DB_PW__'],
                          $baseParams['__YKVAL_DB_OPTIONS__'],
                          $logname . ':db');
    }

    function addField($name, $value)
    {
        $this->myLog->addField($name, $value);
    }

    /**
     * function to convert Db timestamps to unixtime(s)
     *
     * @param string $updated Database timestamp
     * @return int Timestamp in unixtime format
     *
     */
    public function timestampToTime($updated)
    {
        $stamp=strptime($updated, '%F %H:%M:%S');
        return mktime($stamp[tm_hour], $stamp[tm_min], $stamp[tm_sec], $stamp[tm_mon]+1, $stamp[tm_mday], $stamp[tm_year]);

    }

    /**
     * function to compute delta (s) between 2 Db timestamps
     *
     * @param string $first Database timestamp 1
     * @param string $second Database timestamp 2
     * @return int Deltatime (s)
     *
     */
    public function timestampDeltaTime($first, $second)
    {
        return Db::timestampToTime($second) - Db::timestampToTime($first);
    }

    /**
     * function to disconnect from database
     *
     * @return boolean True on success, otherwise false.
     *
     */
    public function disconnect()
    {
        $this->dbh=NULL;
    }

    /**
     * function to check if database is connected
     *
     * @return boolean True if connected, otherwise false.
     *
     */
    public function isConnected()
    {
        if ($this->dbh!=NULL) return True;
        else return False;
    }

    /**
     * function to update row in database by a where condition
     *
     * @param string $table Database table to update row in
     * @param int $id Id on row to update
     * @param array $values Array with key=>values to update
     * @return boolean True on success, otherwise false.
     *
     */
    public function updateBy($table, $k, $v, $values)
    {
        if (!ctype_alnum($v) && !filter_var($v, FILTER_VALIDATE_URL)) {
            $this->myLog->log(LOG_WARNING, "updateBy: attempted to use an invalid value: " . $v);
            return false;
        }
        $query = "";

        foreach ($values as $key=>$value) {
            if ($key != 'server' && !(ctype_alnum($value) || is_null($value))) {
                $this->myLog->log(LOG_WARNING, "updateBy: attempted to write non-alphanumeric to the database: " . $table . "." . $key . " <= " . $value);
                return false;
            }
            elseif ($key == 'server' && !filter_var($value, FILTER_VALIDATE_URL))
            {
                $this->myLog->log(LOG_WARNING, "updateBy: attempted to write invalid URL to the database: " . $table . "." . $key . " <= " . $value);
                return false;
            }
            if (!is_null($value)) $query .= ' ' . $key . "='" . $value . "',";
            else $query .= ' ' . $key . '=NULL,';
        }
        if (! $query) {
            $this->myLog->log(LOG_DEBUG, "no values to set in query. Not updating DB");
            return true;
        }

        $query = rtrim($query, ",") . " WHERE " . $k . " = '" . $v . "'";
        // Insert UPDATE statement at beginning
        $query = "UPDATE " . $table . " SET " . $query;

        return $this->query($query, false);
    }

    /**
     * function to update row in database
     *
     * @param string $table Database table to update row in
     * @param int $id Id on row to update
     * @param array $values Array with key=>values to update
     * @return boolean True on success, otherwise false.
     *
     */
    public function update($table, $id, $values)
    {
        return $this->updateBy($table, 'id', $id, $values);
    }

    /**
     * function to update row in database based on a condition
     *
     * @param string $table Database table to update row in
     * @param string $k Column to select row on
     * @param string $v Value to select row on
     * @param array $values Array with key=>values to update
     * @param string $condition conditional statement
     * @return boolean True on success, otherwise false.
     *
     */
    public function conditionalUpdateBy($table, $k, $v, $values, $condition)
    {
        if (!ctype_alnum($v) || preg_match('/^[a-zA-Z0-9><=()_ ]*$/', $condition) == 0)
        {
            $this->myLog->log(LOG_WARNING, "conditionalUpdateBy: attempted to use non-alphanumeric value: " . $v . " - " . $condition);
            return false;
        }
        $query = ""; /* quiet the PHP Notice */

        foreach ($values as $key=>$value){
            if ($key != 'server' && !is_int($value) && !ctype_alnum($value)) {
                $this->myLog->log(LOG_WARNING, "conditionalUpdateBy: attempted to write non-alphanumeric to the database: " . $value);
                return false;
            }
            elseif ($key == 'server' && !filter_var($value, FILTER_VALIDATE_URL))
            {
                $this->myLog->log(LOG_WARNING, "conditionalUpdateBy: attempted to write invalid URL to the database: " . $value);
                return false;
            }
            $query = $query . " " . $key . "='" . $value . "',";
        }
        if (! $query) {
            $this->myLog->log(LOG_DEBUG, "no values to set in query. Not updating DB");
            return true;
        }

        $query = rtrim($query, ",") . " WHERE " . $k . " = '" . $v . "' and " . $condition;
        // Insert UPDATE statement at beginning
        $query = "UPDATE " . $table . " SET " . $query;

        return $this->query($query, false);
    }

    /**
     * Function to update row in database based on a condition.
     * An ID value is passed to select the appropriate column
     *
     * @param string $table Database table to update row in
     * @param int $id Id on row to update
     * @param array $values Array with key=>values to update
     * @param string $condition conditional statement
     * @return boolean True on success, otherwise false.
     *
     */
    public function conditionalUpdate($table, $id, $values, $condition)
    {
        return $this->conditionalUpdateBy($table, 'id', $id, $values, $condition);
    }

    /**
     * function to insert new row in database
     *
     * @param string $table Database table to update row in
     * @param array $values Array with key=>values to update
     * @return boolean True on success, otherwise false.
     *
     */
    public function save($table, $values)
    {
        $query= 'INSERT INTO ' . $table . " (";
        foreach ($values as $key=>$value){
            if ($key == 'server') {
                $v = filter_var($value, FILTER_VALIDATE_URL);
                if (!$v) {
                    $this->myLog->log(LOG_WARNING, "save: bad server URL provided: " . $value);
                    return false;
                }
                $value = $v;
            } else if ($key == 'info') {
                if (preg_match('/[a-zA-Z0-9&_=,]+/', $value) == 0) {
                    $this->myLog->log(LOG_WARNING, "save: bad info string provided: " . $value);
                    return false;
                }
            } else {
                if ($value != '' && !is_int($value) && !ctype_alnum($value)) {
                    $this->myLog->log(LOG_WARNING, "save: attempted to write non-alphanumeric to the database: " . $value);
                    return false;
                }
            }
            if (!is_null($value)) $query = $query . $key . ",";
        }
        $query = rtrim($query, ",") . ') VALUES (';
        foreach ($values as $key=>$value){
            if (!is_null($value)) $query = $query . "'" . $value . "',";
        }
        $query = rtrim($query, ",");
        $query = $query . ")";
        return $this->query($query, false);
    }
    /**
     * helper function to collect last row[s] in database
     *
     * @param string $table Database table to update row in
     * @param int $nr Number of rows to collect. NULL=>inifinity. DEFAULT=1.
     * @return mixed Array with values from Db row or 2d-array with multiple rows
     or false on failure.
     *
     */
    public function last($table, $nr=1)
    {
        return Db::findBy($table, null, null, $nr, 1);
    }

    /**
     * main function used to get rows from Db table.
     *
     * @param string $table Database table to update row in
     * @param string $key Column to select rows by
     * @param string $value Value to select rows by
     * @param int $nr Number of rows to collect. NULL=>inifinity. Default=NULL.
     * @param int $rev rev=1 indicates order should be reversed. Default=NULL.
     * @return mixed Array with values from Db row or 2d-array with multiple rows
     *
     */
    public function findBy($table, $key, $value, $nr=null, $rev=null)
    {
        return $this->findByMultiple($table, array($key=>$value), $nr, $rev);
    }

    /**
     * Function to do a custom query on database connection
     *
     * @param string $query Database query
     * @return mixed
     *
     */
    public function customQuery($query)
    {
        return $this->query($query, true);
    }
}