<?php

declare(strict_types=1);

namespace LinkCheckup\Features\LinkLists;

use LinkCheckup\Shared\Database\QueryRunner;

use function count;
use function strtoupper;

final class LinkListOrder {

	private const USES_COLUMN       = 'uses_count';
	private const CHECKED_AT_COLUMN = 'links.checked_at';
	private const URL_COLUMN        = 'links.url';
	private const TIE_BREAKER       = ', links.id ASC';

	public function __construct( private QueryRunner $query_runner ) {
	}

	public function order_clause( LinkListQuery $query ): string {
		if ( LinkSortField::Priority === $query->sort_field ) {
			return $this->priority_order();
		}

		return $this->column_of( $query->sort_field ) . ' '
			. strtoupper( $query->sort_direction->value ) . self::TIE_BREAKER;
	}

	private function priority_order(): string {
		$group_ranks = '';

		foreach ( LinkStatusFilter::PROBLEM_VERDICTS as $rank => $verdict ) {
			$group_ranks .= $this->query_runner->prepare(
				' WHEN %s THEN %d',
				$verdict->value,
				$rank
			);
		}

		$last_rank = count( LinkStatusFilter::PROBLEM_VERDICTS );

		return 'CASE links.verdict' . $group_ranks . ' ELSE ' . $last_rank
			. ' END, ' . self::USES_COLUMN . ' DESC' . self::TIE_BREAKER;
	}

	private function column_of( LinkSortField $sort_field ): string {
		if ( LinkSortField::Uses === $sort_field ) {
			return self::USES_COLUMN;
		}

		if ( LinkSortField::CheckedAt === $sort_field ) {
			return self::CHECKED_AT_COLUMN;
		}

		return self::URL_COLUMN;
	}
}