<?php

/**
 * Part of the Joomla Framework Database Package
 *
 * @copyright  Copyright (C) 2005 - 2021 Open Source Matters, Inc. All rights reserved.
 * @license    GNU General Public License version 2 or later; see LICENSE
 */

namespace Joomla\Database\Mysqli;

use Joomla\Database\Exception\ExecutionFailureException;
use Joomla\Database\Exception\PrepareStatementFailureException;
use Joomla\Database\FetchMode;
use Joomla\Database\FetchOrientation;
use Joomla\Database\ParameterType;
use Joomla\Database\StatementInterface;

/**
 * MySQLi Database Statement.
 *
 * This class is modeled on \Doctrine\DBAL\Driver\Mysqli\MysqliStatement
 *
 * @since  2.0.0
 */
class MysqliStatement implements StatementInterface
{
    /**
     * Values which have been bound to the statement.
     *
     * @var    array
     * @since  2.0.0
     */
    protected $bindedValues;

    /**
     * Mapping between named parameters and position in query.
     *
     * @var    array
     * @since  2.0.0
     */
    protected $parameterKeyMapping;

    /**
     * Mapping array for parameter types.
     *
     * @var    array
     * @since  2.0.0
     */
    protected $parameterTypeMapping = [
        ParameterType::BOOLEAN      => 'i',
        ParameterType::INTEGER      => 'i',
        ParameterType::LARGE_OBJECT => 's',
        ParameterType::NULL         => 's',
        ParameterType::STRING       => 's',
    ];

    /**
     * Column names from the executed statement.
     *
     * @var    array|boolean|null
     * @since  2.0.0
     */
    protected $columnNames;

    /**
     * The database connection resource.
     *
     * @var    \mysqli
     * @since  2.0.0
     */
    protected $connection;

    /**
     * The default fetch mode for the statement.
     *
     * @var    integer
     * @since  2.0.0
     */
    protected $defaultFetchStyle = FetchMode::MIXED;

    /**
     * The query string being prepared.
     *
     * @var    string
     * @since  2.0.0
     */
    protected $query;

    /**
     * Internal tracking flag to set whether there is a result set available for processing
     *
     * @var    boolean
     * @since  2.0.0
     */
    private $result = false;

    /**
     * Values which have been bound to the rows of each result set.
     *
     * @var    array
     * @since  2.0.0
     */
    protected $rowBindedValues;

    /**
     * The prepared statement.
     *
     * @var    \mysqli_stmt
     * @since  2.0.0
     */
    protected $statement;

    /**
     * Bound parameter types.
     *
     * @var    array
     * @since  2.0.0
     */
    protected $typesKeyMapping;

    /**
     * Constructor.
     *
     * @param   \mysqli  $connection  The database connection resource
     * @param   string   $query       The query this statement will process
     *
     * @since   2.0.0
     * @throws  PrepareStatementFailureException
     */
    public function __construct(\mysqli $connection, string $query)
    {
        $this->connection   = $connection;
        $this->query        = $query;

        $query = $this->prepareParameterKeyMapping($query);

        $this->statement  = $connection->prepare($query);

        if (!$this->statement) {
            throw new PrepareStatementFailureException($this->connection->error, $this->connection->errno);
        }
    }

    /**
     * Replace named parameters with numbered parameters
     *
     * @param   string  $sql  The SQL statement to prepare.
     *
     * @return  string  The processed SQL statement.
     *
     * @since   2.0.0
     */
    public function prepareParameterKeyMapping($sql)
    {
        $escaped    = false;
        $startPos   = 0;
        $quoteChar  = '';
        $literal    = '';
        $mapping    = [];
        $replace    = [];
        $matches    = [];
        $pattern    = '/([:][a-zA-Z0-9_]+)/';

        if (!preg_match($pattern, $sql, $matches)) {
            return $sql;
        }

        $sql = trim($sql);
        $n   = \strlen($sql);

        while ($startPos < $n) {
            if (!preg_match($pattern, $sql, $matches, 0, $startPos)) {
                break;
            }

            $j = strpos($sql, "'", $startPos);
            $k = strpos($sql, '"', $startPos);

            if (($k !== false) && (($k < $j) || ($j === false))) {
                $quoteChar = '"';
                $j         = $k;
            } else {
                $quoteChar = "'";
            }

            if ($j === false) {
                $j = $n;
            }

            // Search for named prepared parameters and replace it with ? and save its position
            $substring = substr($sql, $startPos, $j - $startPos);

            if (preg_match_all($pattern, $substring, $matches, PREG_PATTERN_ORDER + PREG_OFFSET_CAPTURE)) {
                foreach ($matches[0] as $i => $match) {
                    if ($i === 0) {
                        $literal .= substr($substring, 0, $match[1]);
                    }

                    $mapping[$match[0]]     = \count($mapping);
                    $endOfPlaceholder       = $match[1] + strlen($match[0]);
                    $beginOfNextPlaceholder = $matches[0][$i + 1][1] ?? strlen($substring);
                    $beginOfNextPlaceholder -= $endOfPlaceholder;
                    $literal .= '?' . substr($substring, $endOfPlaceholder, $beginOfNextPlaceholder);
                }
            } else {
                $literal .= $substring;
            }

            $startPos = $j;
            $j++;

            if ($j >= $n) {
                break;
            }

            // Quote comes first, find end of quote
            while (true) {
                $k       = strpos($sql, $quoteChar, $j);
                $escaped = false;

                if ($k === false) {
                    break;
                }

                $l = $k - 1;

                while ($l >= 0 && $sql[$l] === '\\') {
                    $l--;
                    $escaped = !$escaped;
                }

                if ($escaped) {
                    $j = $k + 1;

                    continue;
                }

                break;
            }

            if ($k === false) {
                // Error in the query - no end quote; ignore it
                break;
            }

            $literal .= substr($sql, $startPos, $k - $startPos + 1);
            $startPos = $k + 1;
        }

        if ($startPos < $n) {
            $literal .= substr($sql, $startPos, $n - $startPos);
        }

        $this->parameterKeyMapping = $mapping;

        return $literal;
    }

    /**
     * Binds a parameter to the specified variable name.
     *
     * @param   string|integer  $parameter      Parameter identifier. For a prepared statement using named placeholders, this will be a parameter
     *                                          name of the form `:name`. For a prepared statement using question mark placeholders, this will be
     *                                          the 1-indexed position of the parameter.
     * @param   mixed           $variable       Name of the PHP variable to bind to the SQL statement parameter.
     * @param   integer         $dataType       Constant corresponding to a SQL datatype, this should be the processed type from the QueryInterface.
     * @param   integer         $length         The length of the variable. Usually required for OUTPUT parameters.
     * @param   array           $driverOptions  Optional driver options to be used.
     *
     * @return  boolean
     *
     * @since   2.0.0
     */
    public function bindParam($parameter, &$variable, string $dataType = ParameterType::STRING, ?int $length = null, ?array $driverOptions = null)
    {
        $this->bindedValues[$parameter] =& $variable;

        // Validate parameter type
        if (!isset($this->parameterTypeMapping[$dataType])) {
            throw new \InvalidArgumentException(sprintf('Unsupported parameter type `%s`', $dataType));
        }

        $this->typesKeyMapping[$parameter] = $this->parameterTypeMapping[$dataType];

        return true;
    }

    /**
     * Binds a array of values to bound parameters.
     *
     * @param   array  $values  The values to bind to the statement
     *
     * @return  boolean
     *
     * @since   2.0.0
     */
    private function bindValues(array $values)
    {
        $params = [];
        $types  = str_repeat('s', \count($values));

        if (!empty($this->parameterKeyMapping)) {
            foreach ($values as $key => &$value) {
                $params[$this->parameterKeyMapping[$key]] =& $value;
            }

            ksort($params);
        } else {
            foreach ($values as $key => &$value) {
                $params[] =& $value;
            }
        }

        array_unshift($params, $types);

        return \call_user_func_array([$this->statement, 'bind_param'], $params);
    }

    /**
     * Closes the cursor, enabling the statement to be executed again.
     *
     * @return  void
     *
     * @since   2.0.0
     */
    public function closeCursor(): void
    {
        $this->statement->free_result();
        $this->result = false;
    }

    /**
     * Fetches the SQLSTATE associated with the last operation on the statement handle.
     *
     * @return  int
     *
     * @since   2.0.0
     */
    public function errorCode()
    {
        return $this->statement->errno;
    }

    /**
     * Fetches extended error information associated with the last operation on the statement handle.
     *
     * @return  string
     *
     * @since   2.0.0
     */
    public function errorInfo()
    {
        return $this->statement->error;
    }

    /**
     * Executes a prepared statement
     *
     * @param   array|null  $parameters  An array of values with as many elements as there are bound parameters in the SQL statement being executed.
     *
     * @return  boolean
     *
     * @since   2.0.0
     */
    public function execute(?array $parameters = null)
    {
        if ($this->bindedValues !== null) {
            $params = [];
            $types  = [];

            if (!empty($this->parameterKeyMapping)) {
                foreach ($this->bindedValues as $key => &$value) {
                    $params[$this->parameterKeyMapping[$key]] =& $value;
                    $types[$this->parameterKeyMapping[$key]]  = $this->typesKeyMapping[$key];
                }
            } else {
                foreach ($this->bindedValues as $key => &$value) {
                    $params[]    =& $value;
                    $types[$key] = $this->typesKeyMapping[$key];
                }
            }

            ksort($params);
            ksort($types);

            array_unshift($params, implode('', $types));

            if (!\call_user_func_array([$this->statement, 'bind_param'], $params)) {
                throw new PrepareStatementFailureException($this->statement->error, $this->statement->errno);
            }
        } elseif ($parameters !== null) {
            if (!$this->bindValues($parameters)) {
                throw new PrepareStatementFailureException($this->statement->error, $this->statement->errno);
            }
        }

        try {
            if (!$this->statement->execute()) {
                throw new ExecutionFailureException($this->query, $this->statement->error, $this->statement->errno);
            }
        } catch (\Throwable $e) {
            throw new ExecutionFailureException($this->query, $e->getMessage(), $e->getCode(), $e);
        }

        if ($this->columnNames === null) {
            $meta = $this->statement->result_metadata();

            if ($meta !== false) {
                $columnNames = [];

                foreach ($meta->fetch_fields() as $col) {
                    $columnNames[] = $col->name;
                }

                $meta->free();

                $this->columnNames = $columnNames;
            } else {
                $this->columnNames = false;
            }
        }

        if ($this->columnNames !== false) {
            $this->statement->store_result();

            $this->rowBindedValues = array_fill(0, \count($this->columnNames), null);
            $refs                  = [];

            foreach ($this->rowBindedValues as $key => &$value) {
                $refs[$key] =& $value;
            }

            if (!\call_user_func_array([$this->statement, 'bind_result'], $refs)) {
                throw new \RuntimeException($this->statement->error, $this->statement->errno);
            }
        }

        $this->result = true;

        return true;
    }

    /**
     * Fetches the next row from a result set
     *
     * @param   integer|null  $fetchStyle         Controls how the next row will be returned to the caller. This value must be one of the
     *                                            FetchMode constants, defaulting to value of FetchMode::MIXED.
     * @param   integer       $cursorOrientation  For a StatementInterface object representing a scrollable cursor, this value determines which row
     *                                            will be returned to the caller. This value must be one of the FetchOrientation constants,
     *                                            defaulting to FetchOrientation::NEXT.
     * @param   integer       $cursorOffset       For a StatementInterface object representing a scrollable cursor for which the cursorOrientation
     *                                            parameter is set to FetchOrientation::ABS, this value specifies the absolute number of the row in
     *                                            the result set that shall be fetched. For a StatementInterface object representing a scrollable
     *                                            cursor for which the cursorOrientation parameter is set to FetchOrientation::REL, this value
     *                                            specifies the row to fetch relative to the cursor position before `fetch()` was called.
     *
     * @return  mixed  The return value of this function on success depends on the fetch type. In all cases, boolean false is returned on failure.
     *
     * @since   2.0.0
     */
    public function fetch(?int $fetchStyle = null, int $cursorOrientation = FetchOrientation::NEXT, int $cursorOffset = 0)
    {
        if (!$this->result) {
            return false;
        }

        $fetchStyle = $fetchStyle ?: $this->defaultFetchStyle;

        if ($fetchStyle === FetchMode::COLUMN) {
            return $this->fetchColumn();
        }

        $values = $this->fetchData();

        if ($values === null) {
            return false;
        }

        if ($values === false) {
            throw new \RuntimeException($this->statement->error, $this->statement->errno);
        }

        switch ($fetchStyle) {
            case FetchMode::NUMERIC:
                return $values;

            case FetchMode::ASSOCIATIVE:
                return array_combine($this->columnNames, $values);

            case FetchMode::MIXED:
                $ret = array_combine($this->columnNames, $values);
                $ret += $values;

                return $ret;

            case FetchMode::STANDARD_OBJECT:
                return (object) array_combine($this->columnNames, $values);

            default:
                throw new \InvalidArgumentException("Unknown fetch type '{$fetchStyle}'");
        }
    }

    /**
     * Returns a single column from the next row of a result set
     *
     * @param   integer  $columnIndex  0-indexed number of the column you wish to retrieve from the row.
     *                                 If no value is supplied, the first column is retrieved.
     *
     * @return  mixed  Returns a single column from the next row of a result set or boolean false if there are no more rows.
     *
     * @since   2.0.0
     */
    public function fetchColumn($columnIndex = 0)
    {
        $row = $this->fetch(FetchMode::NUMERIC);

        if ($row === false) {
            return false;
        }

        return $row[$columnIndex] ?? null;
    }

    /**
     * Fetch the data from the statement.
     *
     * @return  array|boolean
     *
     * @since   2.0.0
     */
    private function fetchData()
    {
        $return = $this->statement->fetch();

        if ($return === true) {
            $values = [];

            foreach ($this->rowBindedValues as $v) {
                $values[] = $v;
            }

            return $values;
        }

        return $return;
    }

    /**
     * Returns the number of rows affected by the last SQL statement.
     *
     * @return  integer
     *
     * @since   2.0.0
     */
    public function rowCount(): int
    {
        if ($this->columnNames === false) {
            return $this->statement->affected_rows;
        }

        return $this->statement->num_rows;
    }

    /**
     * Sets the fetch mode to use while iterating this statement.
     *
     * @param   integer  $fetchMode  The fetch mode, must be one of the FetchMode constants.
     * @param   mixed    ...$args    Optional mode-specific arguments.
     *
     * @return  void
     *
     * @since   2.0.0
     */
    public function setFetchMode(int $fetchMode, ...$args): void
    {
        $this->defaultFetchStyle = $fetchMode;
    }
}
