'use client';

import { useState } from 'react';
import { ChevronLeft, ChevronRight } from 'lucide-react';

const PAGE_SIZE_OPTIONS = [10, 20, 50, 100];

interface PaginationProps {
  total: number;
  page: number;
  pageSize: number;
  onChange: (page: number) => void;
  onPageSizeChange: (size: number) => void;
}

export function Pagination({ total, page, pageSize, onChange, onPageSizeChange }: PaginationProps) {
  const totalPages = Math.max(1, Math.ceil(total / pageSize));
  if (total === 0) return null;

  const pages: (number | '...')[] = [];
  if (totalPages <= 7) {
    for (let i = 1; i <= totalPages; i++) pages.push(i);
  } else {
    pages.push(1);
    if (page > 3) pages.push('...');
    const start = Math.max(2, page - 1);
    const end = Math.min(totalPages - 1, page + 1);
    for (let i = start; i <= end; i++) pages.push(i);
    if (page < totalPages - 2) pages.push('...');
    pages.push(totalPages);
  }

  return (
    <div className="flex items-center justify-between px-1 py-3">
      <div className="flex items-center gap-2">
        <span className="text-[12px] text-[var(--ink-muted)]">共 {total} 条</span>
        <select
          value={pageSize}
          onChange={(e) => onPageSizeChange(Number(e.target.value))}
          className="h-7 rounded-md border border-[var(--line)] bg-[var(--bg-card)] px-1.5 text-[12px] text-[var(--ink-soft)] focus:border-[var(--accent)] focus:outline-none"
        >
          {PAGE_SIZE_OPTIONS.map((size) => (
            <option key={size} value={size}>{size} 条/页</option>
          ))}
        </select>
      </div>
      <div className="flex items-center gap-1">
        <button
          disabled={page <= 1}
          onClick={() => onChange(page - 1)}
          className="h-7 w-7 flex items-center justify-center rounded-md border border-[var(--line)] text-[var(--ink-muted)] hover:bg-[var(--bg-subtle)] disabled:opacity-40 disabled:pointer-events-none"
        >
          <ChevronLeft className="h-3.5 w-3.5" />
        </button>
        {pages.map((p, idx) =>
          p === '...' ? (
            <span key={`dots-${idx}`} className="w-7 text-center text-[12px] text-[var(--ink-muted)]">...</span>
          ) : (
            <button
              key={p}
              onClick={() => onChange(p as number)}
              className={`h-7 w-7 flex items-center justify-center rounded-md text-[12px] font-medium transition-colors ${page === p ? 'bg-[var(--accent)] text-white' : 'border border-[var(--line)] text-[var(--ink-soft)] hover:bg-[var(--bg-subtle)]'}`}
            >
              {p}
            </button>
          )
        )}
        <button
          disabled={page >= totalPages}
          onClick={() => onChange(page + 1)}
          className="h-7 w-7 flex items-center justify-center rounded-md border border-[var(--line)] text-[var(--ink-muted)] hover:bg-[var(--bg-subtle)] disabled:opacity-40 disabled:pointer-events-none"
        >
          <ChevronRight className="h-3.5 w-3.5" />
        </button>
      </div>
    </div>
  );
}

export function usePagination<T>(items: T[], defaultPageSize: number = 20) {
  const [page, setPage] = useState(1);
  const [pageSize, setPageSize] = useState(defaultPageSize);

  const total = items.length;
  const totalPages = Math.max(1, Math.ceil(total / pageSize));
  const safePage = Math.min(page, totalPages);
  const paged = items.slice((safePage - 1) * pageSize, safePage * pageSize);

  const handlePageSizeChange = (newSize: number) => {
    setPageSize(newSize);
    setPage(1);
  };

  return { paged, page: safePage, setPage, total, pageSize, setPageSize: handlePageSizeChange };
}