import { useEffect, useMemo, useRef, useState } from 'react'
import { useInfiniteQuery } from '@tanstack/react-query'
import { Ic } from '@/icons'
import { cn } from '@/lib/utils'
import { Popover, PopoverContent, PopoverTrigger } from '@/components/ui/popover'

type SingleSelectProps = {
  label?: string
  items?: string[]
  value: string
  onChange: (value: string) => void
  placeholder?: string
  searchPlaceholder?: string
  emptyLabel?: string
  className?: string
  contentClassName?: string
  searchable?: boolean
  queryKey?: readonly unknown[]
  loadOptions?: (params: { query: string; page: number }) => Promise<{ items: string[]; nextPage?: number }>
}

export default function SingleSelect({
  label,
  items = [],
  value,
  onChange,
  placeholder = 'انتخاب کنید…',
  searchPlaceholder = 'جستجو…',
  emptyLabel,
  className,
  contentClassName,
  searchable = true,
  queryKey,
  loadOptions,
}: SingleSelectProps) {
  const [open, setOpen] = useState(false)
  const [query, setQuery] = useState('')
  const searchRef = useRef<HTMLInputElement>(null)
  const listRef = useRef<HTMLDivElement>(null)

  const infinite = useInfiniteQuery({
    queryKey: [...(queryKey ?? ['single-select-options']), query],
    queryFn: ({ pageParam }) => loadOptions!({ query, page: pageParam }),
    initialPageParam: 1,
    getNextPageParam: (lastPage) => lastPage.nextPage,
    enabled: open && !!loadOptions,
  })

  useEffect(() => {
    if (open && searchable) setTimeout(() => searchRef.current?.focus(), 50)
  }, [open, searchable])

  const setPopoverOpen = (nextOpen: boolean) => {
    if (!nextOpen) setQuery('')
    setOpen(nextOpen)
  }

  const options = useMemo(() => {
    if (loadOptions) return infinite.data?.pages.flatMap((page) => page.items) ?? []
    return query ? items.filter((item) => item.includes(query)) : items
  }, [items, query, loadOptions, infinite.data])

  const renderedOptions = emptyLabel ? [emptyLabel, ...options] : options
  const selectedLabel = value || ''

  const select = (item: string) => {
    onChange(item === emptyLabel ? '' : item)
    setOpen(false)
  }

  const onListScroll = () => {
    const list = listRef.current
    if (!list || !loadOptions || !infinite.hasNextPage || infinite.isFetchingNextPage) return
    if (list.scrollTop + list.clientHeight >= list.scrollHeight - 24) infinite.fetchNextPage()
  }

  return (
    <div className={cn(className)}>
      {label && <p className="mb-1.5 text-[12px] font-semibold text-grey-2">{label}</p>}

      <Popover open={open} onOpenChange={setPopoverOpen}>
        <PopoverTrigger asChild>
          <button
            type="button"
            className={cn(
              'flex h-11 w-full items-center gap-2 rounded-md border border-border-soft bg-input px-3.5 text-right text-[13.5px] outline-none transition-colors hover:bg-white/9',
              open && 'border-red-mid/50',
            )}
          >
            <span className={cn('min-w-0 flex-1 truncate', selectedLabel ? 'text-foreground' : 'text-grey-4')}>
              {selectedLabel || placeholder}
            </span>
            <Ic name="chevDown" className="size-4 shrink-0 opacity-60" />
          </button>
        </PopoverTrigger>

        <PopoverContent
          align="start"
          sideOffset={6}
          className={cn(
            'z-[100] max-h-56 w-[var(--radix-popover-trigger-width)] overflow-y-hidden rounded-lg border border-border-soft bg-[#27282e] p-0 shadow-[0_16px_48px_rgba(0,0,0,.5)]',
            contentClassName,
          )}
        >
          {searchable && (
            <div className="border-b border-border-soft p-2">
              <input
                ref={searchRef}
                type="text"
                value={query}
                onChange={(e) => setQuery(e.target.value)}
                placeholder={searchPlaceholder}
                className="w-full rounded-md border border-border-soft bg-white/5 px-3 py-1.5 text-[12.5px] text-grey-2 outline-none transition-colors placeholder:text-grey-4 focus:border-red-mid/50"
              />
            </div>
          )}

          <div ref={listRef} onScroll={onListScroll} className="max-h-48 overflow-y-auto p-1.5">
            {infinite.isLoading ? (
              <p className="px-3 py-4 text-center text-[12px] text-grey-4">در حال بارگذاری…</p>
            ) : renderedOptions.length === 0 ? (
              <p className="px-3 py-4 text-center text-[12px] text-grey-4">نتیجه‌ای یافت نشد</p>
            ) : (
              renderedOptions.map((item) => {
                const active = item === selectedLabel || (item === emptyLabel && !selectedLabel)
                return (
                  <button
                    key={item}
                    type="button"
                    onClick={() => select(item)}
                    className={cn(
                      'flex w-full cursor-pointer items-center gap-2 rounded-sm px-3 py-2 text-[13px] transition-colors hover:bg-white/8',
                      active ? 'text-foreground' : 'text-grey-2',
                    )}
                  >
                    <span className="flex size-4 shrink-0 items-center justify-center text-red-mid">
                      {active && <Ic name="check" className="size-3.5" />}
                    </span>
                    {item}
                  </button>
                )
              })
            )}
            {infinite.isFetchingNextPage && (
              <div className="flex items-center justify-center gap-2 px-3 py-2 text-[11.5px] text-grey-3">
                <span className="size-3 animate-spin rounded-full border border-white/20 border-t-red-mid" />
                بارگذاری موارد بیشتر…
              </div>
            )}
          </div>
        </PopoverContent>
      </Popover>
    </div>
  )
}