<?php
/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

namespace Apache\Log4php\Pattern;

use Apache\Log4php\Helpers\FormattingInfo;
use Apache\Log4php\LoggingEvent;

/**
 * AbstractConverter is an abstract class that provides the formatting
 * functionality that derived classes need.
 *
 * Conversion specifiers in a conversion patterns are parsed to
 * individual PatternConverters. Each of which is responsible for
 * converting a logging event in a converter specific manner.
 *
 * @license http://www.apache.org/licenses/LICENSE-2.0 Apache License, Version 2.0
 * @since 0.3
 */
abstract class AbstractConverter
{
    /**
     * Next converter in the converter chain.
     * @var AbstractConverter
     */
    public $next = null;

    /**
     * Formatting information, parsed from pattern modifiers.
     * @var FormattingInfo
     */
    protected $formattingInfo;

    /**
     * Converter-specific formatting options.
     * @var array
     */
    protected $option;

    /**
     * Constructor
     * @param FormattingInfo $formattingInfo
     * @param array          $option
     */
    public function __construct(FormattingInfo $formattingInfo = null, $option = null)
    {
        $this->formattingInfo = $formattingInfo;
        $this->option = $option;
        $this->activateOptions();
    }

    /**
     * Called in constructor. Converters which need to process the options
     * can override this method.
     */
    public function activateOptions()
    {

    }

    /**
     * Converts the logging event to the desired format. Derived pattern
     * converters must implement this method.
     *
     * @param LoggingEvent $event
     */
    abstract public function convert(LoggingEvent $event);

    /**
     * Converts the event and formats it according to setting in the
     * Formatting information object.
     *
     * @param string       &$sbuf string buffer to write to
     * @param LoggingEvent $event Event to be formatted.
     */
    public function format(&$sbuf, $event)
    {
        $string = $this->convert($event);

        if (!isset($this->formattingInfo)) {
            $sbuf .= $string;

            return;
        }

        $fi = $this->formattingInfo;

        // Empty string
        if ($string === '' || is_null($string)) {
            if ($fi->min > 0) {
                $sbuf .= str_repeat(' ', $fi->min);
            }

            return;
        }

        $len = strlen($string);

        // Trim the string or add padding if needed
        if ($len > $fi->max) {
            // Trim
            if ($fi->trimLeft) {
                $sbuf .= substr($string, $len - $fi->max, $fi->max);
            } else {
                $sbuf .= substr($string, 0, $fi->max);
            }
        } elseif ($len < $fi->min) {
            // Pad
            if ($fi->padLeft) {
                $sbuf .= str_repeat(' ', $fi->min - $len);
                $sbuf .= $string;
            } else {
                $sbuf .= $string;
                $sbuf .= str_repeat(' ', $fi->min - $len);
            }
        } else {
            // No action needed
            $sbuf .= $string;
        }
    }
}