<?php

namespace WP_CLI\I18n;

use DirectoryIterator;
use Gettext\Extractors\Po;
use Gettext\Merge;
use Gettext\Translations;
use IteratorIterator;
use SplFileInfo;
use WP_CLI;
use WP_CLI\Utils;
use WP_CLI_Command;

class UpdatePoCommand extends WP_CLI_Command {
    /**
     * Update PO files from a POT file.
     *
     * This behaves similarly to the [msgmerge](https://www.gnu.org/software/gettext/manual/html_node/msgmerge-Invocation.html) command.
     *
     * ## OPTIONS
     *
     * <source>
     * : Path to an existing POT file to use for updating.
     *
     * [<destination>]
     * : PO file to update or a directory containing multiple PO files.
     *   Defaults to all PO files in the source directory.
     *
     * ## EXAMPLES
     *
     *     # Update all PO files from a POT file in the current directory.
     *     $ wp i18n update-po example-plugin.pot
     *     Success: Updated 3 files.
     *
     *     # Update a PO file from a POT file.
     *     $ wp i18n update-po example-plugin.pot example-plugin-de_DE.po
     *     Success: Updated 1 file.
     *
     *     # Update all PO files in a given directory from a POT file.
     *     $ wp i18n update-po example-plugin.pot languages
     *     Success: Updated 2 files.
     *
     * @when before_wp_load
     *
     * @throws WP_CLI\ExitException
     */
    public function __invoke( $args, $assoc_args ) {
        $source = realpath( $args[0] );
        if ( ! $source || ! is_file( $source ) ) {
            WP_CLI::error( 'Source file does not exist.' );
        }

        $destination = dirname( $source );

        if ( isset( $args[1] ) ) {
            $destination = $args[1];
        }

        if ( ! file_exists( $destination ) ) {
            WP_CLI::error( 'Destination file/folder does not exist.' );
        }

        if ( is_file( $destination ) ) {
            $files = [ new SplFileInfo( $destination ) ];
        } else {
            $files = new IteratorIterator( new DirectoryIterator( $destination ) );
        }

        $pot_translations = Translations::fromPoFile( $source );

        $result_count = 0;
        /** @var DirectoryIterator $file */
        foreach ( $files as $file ) {
            if ( 'po' !== $file->getExtension() ) {
                continue;
            }

            if ( ! $file->isFile() || ! $file->isReadable() ) {
                WP_CLI::warning( sprintf( 'Could not read file %s', $file->getFilename() ) );
                continue;
            }

            $po_translations = Translations::fromPoFile( $file->getPathname() );
            $po_translations->mergeWith(
                $pot_translations,
                Merge::ADD | Merge::REMOVE | Merge::COMMENTS_THEIRS | Merge::EXTRACTED_COMMENTS_THEIRS | Merge::REFERENCES_THEIRS | Merge::DOMAIN_OVERRIDE
            );

            if ( ! $po_translations->toPoFile( $file->getPathname() ) ) {
                WP_CLI::warning( sprintf( 'Could not update file %s', $file->getPathname() ) );
                continue;
            }

            ++$result_count;
        }

        WP_CLI::success( sprintf( 'Updated %d %s.', $result_count, Utils\pluralize( 'file', $result_count ) ) );
    }
}