import { ChevronLeft, ChevronRight } from "lucide-react"
import type { ChangeEvent } from "react"

import { Button } from "@/shared/ui/button"
import { cn } from "@/shared/ui/utils"

interface PaginationProps {
  page: number
  pageSize: number
  total: number
  pageSizeOptions?: readonly number[]
  onPageChange: (page: number) => void
  onPageSizeChange: (pageSize: number) => void
}

const DEFAULT_PAGE_SIZE_OPTIONS = [10, 20, 50] as const

function clamp(value: number, min: number, max: number) {
  return Math.min(max, Math.max(min, value))
}

function rangeLabel(page: number, pageSize: number, total: number) {
  if (total <= 0) return "共 0 条"
  const start = (page - 1) * pageSize + 1
  const end = Math.min(page * pageSize, total)
  return `第 ${start}–${end} 条，共 ${total} 条`
}

function buildPageItems(page: number, pageCount: number) {
  if (pageCount <= 1) return [1]
  const items: Array<number | "ellipsis"> = [1]
  const start = Math.max(2, page - 1)
  const end = Math.min(pageCount - 1, page + 1)
  if (start > 2) items.push("ellipsis")
  for (let p = start; p <= end; p += 1) items.push(p)
  if (end < pageCount - 1) items.push("ellipsis")
  if (pageCount > 1) items.push(pageCount)
  return items
}

export function Pagination({
  page,
  pageSize,
  total,
  pageSizeOptions = DEFAULT_PAGE_SIZE_OPTIONS,
  onPageChange,
  onPageSizeChange,
}: PaginationProps) {
  const pageCount = Math.max(1, Math.ceil(total / pageSize))
  const currentPage = clamp(page, 1, pageCount)
  const hasPrev = currentPage > 1
  const hasNext = currentPage < pageCount
  const items = buildPageItems(currentPage, pageCount)

  function handlePageSizeChange(event: ChangeEvent<HTMLSelectElement>) {
    onPageSizeChange(Number(event.target.value))
  }

  return (
    <footer
      aria-label="表格分页"
      className="flex min-h-12 flex-wrap items-center gap-3 border-t border-border/60 px-3 py-2 text-xs text-muted-foreground"
    >
      <span className="tabular-nums" aria-live="polite">
        {rangeLabel(currentPage, pageSize, total)}
      </span>
      <label className="ml-auto flex items-center gap-1.5">
        每页
        <select
          className="h-11 rounded-md border border-input bg-card px-2 text-xs text-foreground outline-none focus-visible:border-ring focus-visible:ring-3 focus-visible:ring-ring/50 md:h-7"
          aria-label="每页数量"
          value={pageSize}
          onChange={handlePageSizeChange}
        >
          {pageSizeOptions.map((option) => (
            <option key={option} value={option}>
              {option}
            </option>
          ))}
        </select>
        条
      </label>
      <div className="flex items-center gap-1">
        <Button
          aria-label="上一页"
          disabled={!hasPrev}
          onClick={() => onPageChange(currentPage - 1)}
          className="size-11 md:size-7"
          size="icon-sm"
          variant="ghost"
        >
          <ChevronLeft aria-hidden="true" />
        </Button>
        {items.map((item, index) => {
          if (item === "ellipsis") {
            return (
              <span
                key={`ellipsis-${index}`}
                className="px-1.5 text-muted-foreground/70"
                aria-hidden="true"
              >
                …
              </span>
            )
          }
          const active = item === currentPage
          return (
            <button
              key={item}
              type="button"
              aria-current={active ? "page" : undefined}
              aria-label={`第 ${item} 页`}
              onClick={() => onPageChange(item)}
              className={cn(
                "size-11 rounded-md border border-transparent text-xs tabular-nums transition-colors outline-none focus-visible:border-ring focus-visible:ring-3 focus-visible:ring-ring/50 md:size-7",
                active
                  ? "bg-primary text-primary-foreground"
                  : "text-muted-foreground hover:bg-muted hover:text-foreground",
              )}
            >
              {item}
            </button>
          )
        })}
        <Button
          aria-label="下一页"
          disabled={!hasNext}
          onClick={() => onPageChange(currentPage + 1)}
          className="size-11 md:size-7"
          size="icon-sm"
          variant="ghost"
        >
          <ChevronRight aria-hidden="true" />
        </Button>
      </div>
    </footer>
  )
}