<?php

/*
 * This file is part of SwiftMailer.
 * (c) 2004-2009 Chris Corbyn
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

/**
 * A MIME part, in a multipart message.
 *
 * @author Chris Corbyn
 */
class Swift_Mime_MimePart extends Swift_Mime_SimpleMimeEntity
{
    /** The format parameter last specified by the user */
    protected $userFormat;

    /** The charset last specified by the user */
    protected $userCharset;

    /** The delsp parameter last specified by the user */
    protected $userDelSp;

    /** The nesting level of this MimePart */
    private $nestingLevel = self::LEVEL_ALTERNATIVE;

    /**
     * Create a new MimePart with $headers, $encoder and $cache.
     *
     * @param string $charset
     */
    public function __construct(Swift_Mime_SimpleHeaderSet $headers, Swift_Mime_ContentEncoder $encoder, Swift_KeyCache $cache, Swift_IdGenerator $idGenerator, $charset = null)
    {
        parent::__construct($headers, $encoder, $cache, $idGenerator);
        $this->setContentType('text/plain');
        if (null !== $charset) {
            $this->setCharset($charset);
        }
    }

    /**
     * Set the body of this entity, either as a string, or as an instance of
     * {@link Swift_OutputByteStream}.
     *
     * @param mixed  $body
     * @param string $contentType optional
     * @param string $charset     optional
     *
     * @return $this
     */
    public function setBody($body, $contentType = null, $charset = null)
    {
        if (isset($charset)) {
            $this->setCharset($charset);
        }
        $body = $this->convertString($body);

        parent::setBody($body, $contentType);

        return $this;
    }

    /**
     * Get the character set of this entity.
     *
     * @return string
     */
    public function getCharset()
    {
        return $this->getHeaderParameter('Content-Type', 'charset');
    }

    /**
     * Set the character set of this entity.
     *
     * @param string $charset
     *
     * @return $this
     */
    public function setCharset($charset)
    {
        $this->setHeaderParameter('Content-Type', 'charset', $charset);
        if ($charset !== $this->userCharset) {
            $this->clearCache();
        }
        $this->userCharset = $charset;
        parent::charsetChanged($charset);

        return $this;
    }

    /**
     * Get the format of this entity (i.e. flowed or fixed).
     *
     * @return string
     */
    public function getFormat()
    {
        return $this->getHeaderParameter('Content-Type', 'format');
    }

    /**
     * Set the format of this entity (flowed or fixed).
     *
     * @param string $format
     *
     * @return $this
     */
    public function setFormat($format)
    {
        $this->setHeaderParameter('Content-Type', 'format', $format);
        $this->userFormat = $format;

        return $this;
    }

    /**
     * Test if delsp is being used for this entity.
     *
     * @return bool
     */
    public function getDelSp()
    {
        return 'yes' === $this->getHeaderParameter('Content-Type', 'delsp');
    }

    /**
     * Turn delsp on or off for this entity.
     *
     * @param bool $delsp
     *
     * @return $this
     */
    public function setDelSp($delsp = true)
    {
        $this->setHeaderParameter('Content-Type', 'delsp', $delsp ? 'yes' : null);
        $this->userDelSp = $delsp;

        return $this;
    }

    /**
     * Get the nesting level of this entity.
     *
     * @see LEVEL_TOP, LEVEL_ALTERNATIVE, LEVEL_MIXED, LEVEL_RELATED
     *
     * @return int
     */
    public function getNestingLevel()
    {
        return $this->nestingLevel;
    }

    /**
     * Receive notification that the charset has changed on this document, or a
     * parent document.
     *
     * @param string $charset
     */
    public function charsetChanged($charset)
    {
        $this->setCharset($charset);
    }

    /** Fix the content-type and encoding of this entity */
    protected function fixHeaders()
    {
        parent::fixHeaders();
        if (count($this->getChildren())) {
            $this->setHeaderParameter('Content-Type', 'charset', null);
            $this->setHeaderParameter('Content-Type', 'format', null);
            $this->setHeaderParameter('Content-Type', 'delsp', null);
        } else {
            $this->setCharset($this->userCharset);
            $this->setFormat($this->userFormat);
            $this->setDelSp($this->userDelSp);
        }
    }

    /** Set the nesting level of this entity */
    protected function setNestingLevel($level)
    {
        $this->nestingLevel = $level;
    }

    /** Encode charset when charset is not utf-8 */
    protected function convertString($string)
    {
        $charset = strtolower($this->getCharset() ?? '');
        if (!in_array($charset, ['utf-8', 'iso-8859-1', 'iso-8859-15', ''])) {
            // mb_convert_encoding must be the first one to check, since iconv cannot convert some words.
            if (function_exists('mb_convert_encoding')) {
                $string = mb_convert_encoding($string, $charset, 'utf-8');
            } elseif (function_exists('iconv')) {
                $string = iconv('utf-8//TRANSLIT//IGNORE', $charset, $string);
            } else {
                throw new Swift_SwiftException('No suitable convert encoding function (use UTF-8 as your charset or install the mbstring or iconv extension).');
            }

            return $string;
        }

        return $string;
    }
}
