<?php

declare(strict_types=1);

namespace LinkCheckup\Features\Scanning;

use LinkCheckup\Shared\Database\QueryRunner;
use LinkCheckup\Shared\Database\Tables;
use LinkCheckup\Shared\Links\Outcome;
use LinkCheckup\Shared\Links\Reason;
use LinkCheckup\Shared\Links\Verdict;

final class ScanLinks {

	private const EVERY_LINK = '1 = 1';

	public function __construct(
		private QueryRunner $query_runner,
		private Tables $tables
	) {
	}

	public function mark_all_due(): void {
		$this->query_runner->execute(
			$this->query_runner->prepare(
				'UPDATE ' . $this->tables->links()
					. ' SET check_after = 0 WHERE outcome = %s',
				Outcome::Listed->value
			)
		);
	}

	public function listed_total(): int {
		return $this->listed_count_where( self::EVERY_LINK );
	}

	public function recheck_unconfirmed(): void {
		$this->query_runner->execute(
			$this->query_runner->prepare(
				'UPDATE ' . $this->tables->links()
					. ' SET check_after = 0 WHERE outcome = %s AND ',
				Outcome::Listed->value
			) . $this->unconfirmed_condition()
		);
	}

	public function settled_since( int $started_at ): int {
		return $this->listed_count_where(
			'checked_at >= %d AND NOT ' . $this->unconfirmed_condition(),
			$started_at
		);
	}

	public function unfinished_total( int $started_at, int $now ): int {
		return $this->listed_count_where(
			'( ( check_after <= %d
			AND ( checked_at IS NULL OR checked_at < %d ) )
			OR ' . $this->unconfirmed_condition() . ' )',
			$now,
			$started_at
		);
	}

	private function unconfirmed_condition(): string {
		$reasons = array();

		foreach ( Reason::cases() as $reason ) {
			if ( $reason->is_confirmed_by_repeating() ) {
				$reasons[] = $reason->value;
			}
		}

		$placeholders = array_fill( 0, count( $reasons ), '%s' );

		return $this->query_runner->prepare(
			'( verdict = %s AND reason IS NOT NULL AND reason IN ('
				. implode( ', ', $placeholders ) . ') )',
			Verdict::Retrying->value,
			...$reasons
		);
	}

	private function listed_count_where(
		string $condition,
		int ...$values
	): int {
		$count = $this->query_runner->value(
			$this->query_runner->prepare(
				'SELECT COUNT(*) FROM ' . $this->tables->links()
					. ' WHERE outcome = %s AND ' . $condition,
				Outcome::Listed->value,
				...$values
			)
		);

		return (int) $count;
	}
}