<?php
declare(strict_types=1);

namespace App\Dto;

/**
 * 分页数据传输对象
 */
class PaginationDto extends BaseDto
{
    private array $items = [];

    #[Required]
    private int $total = 0;

    #[Required]
    private int $page = 1;

    #[Required]
    private int $pageSize = 10;

    private ?int $totalPages = null;

    private ?bool $hasMore = null;

    private ?bool $hasPrev = null;

    private ?bool $hasNext = null;

    private ?int $from = null;

    private ?int $to = null;

    private array $filters = [];

    private array $sorts = [];

    public function getItems(): array
    {
        return $this->items;
    }

    public function setItems(array $items): self
    {
        $this->items = $items;
        $this->calculateDerivedValues();
        return $this;
    }

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

    public function setTotal(int $total): self
    {
        $this->total = $total;
        $this->calculateDerivedValues();
        return $this;
    }

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

    public function setPage(int $page): self
    {
        $this->page = max(1, $page);
        $this->calculateDerivedValues();
        return $this;
    }

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

    public function setPageSize(int $pageSize): self
    {
        $this->pageSize = max(1, $pageSize);
        $this->calculateDerivedValues();
        return $this;
    }

    public function getTotalPages(): ?int
    {
        return $this->totalPages;
    }

    public function getHasMore(): ?bool
    {
        return $this->hasMore;
    }

    public function getHasPrev(): ?bool
    {
        return $this->hasPrev;
    }

    public function getHasNext(): ?bool
    {
        return $this->hasNext;
    }

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

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

    public function getFilters(): array
    {
        return $this->filters;
    }

    public function setFilters(array $filters): self
    {
        $this->filters = $filters;
        return $this;
    }

    public function getSorts(): array
    {
        return $this->sorts;
    }

    public function setSorts(array $sorts): self
    {
        $this->sorts = $sorts;
        return $this;
    }

    /**
     * 添加过滤器
     */
    public function addFilter(string $key, mixed $value): self
    {
        $this->filters[$key] = $value;
        return $this;
    }

    /**
     * 添加排序
     */
    public function addSort(string $field, string $direction = 'asc'): self
    {
        $this->sorts[$field] = strtolower($direction);
        return $this;
    }

    /**
     * 计算派生值
     */
    private function calculateDerivedValues(): void
    {
        $this->totalPages = $this->pageSize > 0 ? (int) ceil($this->total / $this->pageSize) : 0;
        $this->hasMore = $this->page * $this->pageSize < $this->total;
        $this->hasPrev = $this->page > 1;
        $this->hasNext = $this->page < $this->totalPages;
        $this->from = $this->total > 0 ? (($this->page - 1) * $this->pageSize) + 1 : null;
        $this->to = min($this->page * $this->pageSize, $this->total);
    }

    /**
     * 获取偏移量
     */
    public function getOffset(): int
    {
        return ($this->page - 1) * $this->pageSize;
    }

    /**
     * 获取限制数量
     */
    public function getLimit(): int
    {
        return $this->pageSize;
    }

    /**
     * 检查是否为第一页
     */
    public function isFirstPage(): bool
    {
        return $this->page === 1;
    }

    /**
     * 检查是否为最后一页
     */
    public function isLastPage(): bool
    {
        return !$this->hasNext;
    }

    /**
     * 获取上一页页码
     */
    public function getPrevPage(): ?int
    {
        return $this->hasPrev ? $this->page - 1 : null;
    }

    /**
     * 获取下一页页码
     */
    public function getNextPage(): ?int
    {
        return $this->hasNext ? $this->page + 1 : null;
    }

    /**
     * 创建分页对象
     */
    public static function create(array $items, int $total, int $page = 1, int $pageSize = 10): self
    {
        return (new self())
            ->setItems($items)
            ->setTotal($total)
            ->setPage($page)
            ->setPageSize($pageSize);
    }

    /**
     * 从查询结果创建分页对象
     */
    public static function fromQuery(array $items, int $total, array $params = []): self
    {
        $page = (int) ($params['page'] ?? 1);
        $pageSize = (int) ($params['page_size'] ?? $params['limit'] ?? 10);
        $filters = $params['filters'] ?? [];
        $sorts = $params['sorts'] ?? [];

        return (new self())
            ->setItems($items)
            ->setTotal($total)
            ->setPage($page)
            ->setPageSize($pageSize)
            ->setFilters($filters)
            ->setSorts($sorts);
    }

    /**
     * 转换为数组
     */
    public function toArray(): array
    {
        return [
            'items' => $this->items,
            'pagination' => [
                'total' => $this->total,
                'page' => $this->page,
                'page_size' => $this->pageSize,
                'total_pages' => $this->totalPages,
                'has_more' => $this->hasMore,
                'has_prev' => $this->hasPrev,
                'has_next' => $this->hasNext,
                'from' => $this->from,
                'to' => $this->to,
                'prev_page' => $this->getPrevPage(),
                'next_page' => $this->getNextPage(),
            ],
            'filters' => empty($this->filters) ? null : $this->filters,
            'sorts' => empty($this->sorts) ? null : $this->sorts,
        ];
    }

    /**
     * 获取分页信息数组
     */
    public function getPaginationInfo(): array
    {
        return [
            'total' => $this->total,
            'page' => $this->page,
            'page_size' => $this->pageSize,
            'total_pages' => $this->totalPages,
            'has_more' => $this->hasMore,
            'has_prev' => $this->hasPrev,
            'has_next' => $this->hasNext,
            'from' => $this->from,
            'to' => $this->to,
            'prev_page' => $this->getPrevPage(),
            'next_page' => $this->getNextPage(),
        ];
    }

    /**
     * 获取SQL LIMIT子句
     */
    public function getSqlLimit(): string
    {
        return "LIMIT {$this->pageSize} OFFSET " . $this->getOffset();
    }

    /**
     * 验证分页参数
     */
    public function validate(): array
    {
        $errors = parent::validate();

        if ($this->page < 1) {
            $errors['page'] = 'Page must be greater than 0';
        }

        if ($this->pageSize < 1 || $this->pageSize > 1000) {
            $errors['page_size'] = 'Page size must be between 1 and 1000';
        }

        if ($this->total < 0) {
            $errors['total'] = 'Total must be greater than or equal to 0';
        }

        return $errors;
    }

    /**
     * 克隆分页对象，修改页码
     */
    public function withPage(int $page): self
    {
        $new = clone $this;
        $new->setPage($page);
        return $new;
    }

    /**
     * 克隆分页对象，修改页大小
     */
    public function withPageSize(int $pageSize): self
    {
        $new = clone $this;
        $new->setPageSize($pageSize);
        return $new;
    }

    /**
     * 克隆分页对象，修改过滤器
     */
    public function withFilters(array $filters): self
    {
        $new = clone $this;
        $new->setFilters($filters);
        return $new;
    }

    /**
     * 克隆分页对象，修改排序
     */
    public function withSorts(array $sorts): self
    {
        $new = clone $this;
        $new->setSorts($sorts);
        return $new;
    }
}