<?php

declare(strict_types=1);

namespace LinkCheckup\Features\Fixes;

use LinkCheckup\Shared\DataVersion;

use function array_reverse;
use function array_slice;

final class FixUndoer implements FixStep {

	public function __construct(
		private PostContentWriter $post_content_writer,
		private LinkOutcomeStore $link_outcome_store,
		private FixRepository $fix_repository,
		private DataVersion $data_version
	) {
	}

	public function next_step( Fix $fix ): Fix {
		if ( FixState::Undone === $fix->progress->state ) {
			return $fix;
		}

		$undoing  = $fix->with_progress(
			$fix->progress->with_state( FixState::Undoing )
		);
		$restored = $this->restore_posts( $undoing );
		$stepped  = array() === $restored->progress->journal
			? $this->revert_links( $restored )
			: $restored;

		$this->fix_repository->save_progress( $stepped );
		$this->data_version->bump();

		return $stepped;
	}

	private function restore_posts( Fix $fix ): Fix {
		$newest_entries = array_slice(
			array_reverse( $fix->progress->journal ),
			0,
			StepLimits::POSTS_PER_STEP
		);

		foreach ( $newest_entries as $entry ) {
			$this->post_content_writer->restore( $entry );
			$fix = $fix->with_progress( $fix->progress->without_last_place() );
			$this->fix_repository->save_progress( $fix );
		}

		return $fix;
	}

	private function revert_links( Fix $fix ): Fix {
		$reverted = $this->link_outcome_store->revert(
			$fix->id,
			StepLimits::LINKS_PER_STEP
		);
		$progress = $fix->progress->with_links_done(
			$fix->progress->links_done - $reverted
		);

		if ( $reverted >= StepLimits::LINKS_PER_STEP ) {
			return $fix->with_progress( $progress );
		}

		return $fix->with_progress(
			$progress->with_links_done( 0 )->with_state( FixState::Undone )
		);
	}
}