<?php

/**

 * I18N: WP_Translation_File_MO class.

 *

 * @package WordPress

 * @subpackage I18N

 * @since 6.5.0

 */

/**

 * Class WP_Translation_File_MO.

 *

 * @since 6.5.0

 */

class WP_Translation_File_MO extends WP_Translation_File {

	/**

	 * Endian value.

	 *

	 * V for little endian, N for big endian, or false.

	 *

	 * Used for unpack().

	 *

	 * @since 6.5.0

	 * @var false|'V'|'N'

	 */

	protected $uint32 = false;

	/**

	 * The magic number of the GNU message catalog format.

	 *

	 * @since 6.5.0

	 * @var int

	 */

	const MAGIC_MARKER = 0x950412de;

	/**

	 * Detects endian and validates file.

	 *

	 * @since 6.5.0

	 *

	 * @param string $header File contents.

	 * @return false|'V'|'N' V for little endian, N for big endian, or false on failure.

	 */

	protected function detect_endian_and_validate_file( string $header ) {

		$big = unpack( 'N', $header );

		if ( false === $big ) {

			return false;

		}

		$big = reset( $big );

		if ( false === $big ) {

			return false;

		}

		$little = unpack( 'V', $header );

		if ( false === $little ) {

			return false;

		}

		$little = reset( $little );

		if ( false === $little ) {

			return false;

		}

		// Force cast to an integer as it can be a float on x86 systems. See https://core.trac.wordpress.org/ticket/60678.

		if ( (int) self::MAGIC_MARKER === $big ) {

			return 'N';

		}

		// Force cast to an integer as it can be a float on x86 systems. See https://core.trac.wordpress.org/ticket/60678.

		if ( (int) self::MAGIC_MARKER === $little ) {

			return 'V';

		}

		$this->error = 'Magic marker does not exist';

		return false;

	}

	/**

	 * Parses the file.

	 *

	 * @since 6.5.0

	 *

	 * @return bool True on success, false otherwise.

	 */

	protected function parse_file(): bool {

		$this->parsed = true;

		$file_contents = file_get_contents( $this->file ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents

		if ( false === $file_contents ) {

			return false;

		}

		$file_length = strlen( $file_contents );

		if ( $file_length < 24 ) {

			$this->error = 'Invalid data';

			return false;

		}

		$this->uint32 = $this->detect_endian_and_validate_file( substr( $file_contents, 0, 4 ) );

		if ( false === $this->uint32 ) {

			return false;

		}

		$offsets = substr( $file_contents, 4, 24 );

		if ( false === $offsets ) {

			return false;

		}

		$offsets = unpack( "{$this->uint32}rev/{$this->uint32}total/{$this->uint32}originals_addr/{$this->uint32}translations_addr/{$this->uint32}hash_length/{$this->uint32}hash_addr", $offsets );

		if ( false === $offsets ) {

			return false;

		}

		$offsets['originals_length']    = $offsets['translations_addr'] - $offsets['originals_addr'];

		$offsets['translations_length'] = $offsets['hash_addr'] - $offsets['translations_addr'];

		if ( $offsets['rev'] > 0 ) {

			$this->error = 'Unsupported revision';

			return false;

		}

		if ( $offsets['translations_addr'] > $file_length || $offsets['originals_addr'] > $file_length ) {

			$this->error = 'Invalid data';

			return false;

		}

		// Load the Originals.

		$original_data     = str_split( substr( $file_contents, $offsets['originals_addr'], $offsets['originals_length'] ), 8 );

		$translations_data = str_split( substr( $file_contents, $offsets['translations_addr'], $offsets['translations_length'] ), 8 );

		foreach ( array_keys( $original_data ) as $i ) {

			$o = unpack( "{$this->uint32}length/{$this->uint32}pos", $original_data[ $i ] );

			$t = unpack( "{$this->uint32}length/{$this->uint32}pos", $translations_data[ $i ] );

			if ( false === $o || false === $t ) {

				continue;

			}

			$original    = substr( $file_contents, $o['pos'], $o['length'] );

			$translation = substr( $file_contents, $t['pos'], $t['length'] );

			// GlotPress bug.

			$translation = rtrim( $translation, "\0" );

			// Metadata about the MO file is stored in the first translation entry.

			if ( '' === $original ) {

				foreach ( explode( "\n", $translation ) as $meta_line ) {

						continue;

					}

					list( $name, $value ) = array_map( 'trim', explode( ':', $meta_line, 2 ) );

					$this->headers[ strtolower( $name ) ] = $value;

				}

			} else {

				/*

				 * In MO files, the key normally contains both singular and plural versions.

				 * However, this just adds the singular string for lookup,

				 * which caters for cases where both __( 'Product' ) and _n( 'Product', 'Products' )

				 * are used and the translation is expected to be the same for both.

				 */

				$parts = explode( "\0", (string) $original );

				$this->entries[ $parts[0] ] = $translation;

			}

		}

		return true;

	}

	/**

	 * Exports translation contents as a string.

	 *

	 * @since 6.5.0

	 *

	 * @return string Translation file contents.

	 */

	public function export(): string {

		// Prefix the headers as the first key.

		$headers_string = '';

		foreach ( $this->headers as $header => $value ) {

			$headers_string .= "{$header}: $value\n";

		}

		$entries     = array_merge( array( '' => $headers_string ), $this->entries );

		$entry_count = count( $entries );

		if ( false === $this->uint32 ) {

			$this->uint32 = 'V';

		}

		$bytes_for_entries = $entry_count * 4 * 2;

		// Pair of 32bit ints per entry.

		$originals_addr    = 28; /* header */

		$translations_addr = $originals_addr + $bytes_for_entries;

		$hash_addr         = $translations_addr + $bytes_for_entries;

		$entry_offsets     = $hash_addr;

		$file_header = pack(

			$this->uint32 . '*',

			// Force cast to an integer as it can be a float on x86 systems. See https://core.trac.wordpress.org/ticket/60678.

			(int) self::MAGIC_MARKER,

			0, /* rev */

			$entry_count,

			$originals_addr,

			$translations_addr,

			0, /* hash_length */

			$hash_addr

		);

		$o_entries = '';

		$t_entries = '';

		$o_addr    = '';

		$t_addr    = '';

		foreach ( array_keys( $entries ) as $original ) {

			$o_addr        .= pack( $this->uint32 . '*', strlen( $original ), $entry_offsets );

			$entry_offsets += strlen( $original ) + 1;

			$o_entries     .= $original . "\0";

		}

		foreach ( $entries as $translations ) {

			$t_addr        .= pack( $this->uint32 . '*', strlen( $translations ), $entry_offsets );

			$entry_offsets += strlen( $translations ) + 1;

			$t_entries     .= $translations . "\0";

		}

		return $file_header . $o_addr . $t_addr . $o_entries . $t_entries;

	}

}