<?php

declare(strict_types=1);

namespace Shared\Pagination;

use Shared\DDD\Equatable;

/**
 * Immutable value object representing a pagination range.
 */
final readonly class Pagination implements Equatable
{
    /** ERR_TOO_MANY_RECORDS fixed to 10k */
    public const int MAX_PAGE_SIZE = PageSize::MAX_PAGE_SIZE;

    private function __construct(
        private int $from,
        private int $to,
    ) {
    }

    public function from(): int
    {
        return $this->from;
    }

    public function to(): int
    {
        return $this->to;
    }

    public function pageSize(): PageSize
    {
        return new PageSize($this->to - $this->from + 1);
    }

    public function pageNumber(): PageNumber
    {
        return new PageNumber((int) ($this->from / $this->pageSize()->value()) + 1);
    }

    public function equals(mixed $other): bool
    {
        return $other instanceof self && $this->from === $other->from && $this->to === $other->to;
    }

    public static function ofIndexes(int $from, int $to): self
    {
        $from = max(0, $from);
        $to   = clamp($to, $from + 1, $from + self::MAX_PAGE_SIZE);

        return new self($from, $to);
    }

    public static function ofPage(PageNumber $pageNumber, PageSize $pageSize = new PageSize()): self
    {
        $fromIndex = ($pageNumber->value - 1) * $pageSize->value;
        $toIndex   = $fromIndex + $pageSize->value - 1;

        return new self($fromIndex, $toIndex);
    }

    public static function ofOffsetAndLimit(int $offset, int $limit): self
    {
        $offset = max(0, $offset);
        $limit  = clamp($limit, 1, self::MAX_PAGE_SIZE);

        $fromIndex = $offset;
        $toIndex   = $offset + $limit - 1;

        return new self($fromIndex, $toIndex);
    }

    public static function firstPage(PageSize $pageSize = new PageSize()): self
    {
        return self::ofPage(new PageNumber(1), $pageSize);
    }

    public function __toString(): string
    {
        return sprintf('Pagination{from=%d, to=%d}', $this->from, $this->to);
    }
}