import { useEffect, useMemo, useRef, useState } from 'react'
import { ChevronDown, Loader2, Search, X } from 'lucide-react'
import { useLocale } from '@meshkee/dashboard-ui'
import { useT } from '../i18n/useT'
import styles from './SearchableSelect.module.css'

export const PRODUCT_SEARCH_DEBOUNCE_MS = 350

export interface ProductSearchOption {
  id: string
  title: string
  nameFa: string
}

interface ProductSearchSelectProps {
  options: ProductSearchOption[]
  value: string
  onChange: (value: string) => void
  placeholder?: string
  disabled?: boolean
  id?: string
  minSearchLength?: number
  isSearching?: boolean
  /**
   * When set, typing is debounced and the parent fetches results.
   * Local filtering is skipped.
   */
  onQueryChange?: (query: string) => void
  debounceMs?: number
  'aria-label'?: string
}

function formatProductLabel(option: ProductSearchOption, preferFa: boolean) {
  if (preferFa && option.nameFa) {
    return option.title ? `${option.nameFa} / ${option.title}` : option.nameFa
  }
  return option.nameFa ? `${option.title} / ${option.nameFa}` : option.title
}

export function ProductSearchSelect({
  options,
  value,
  onChange,
  placeholder = 'Search products...',
  disabled = false,
  id,
  minSearchLength = 3,
  isSearching = false,
  onQueryChange,
  debounceMs = PRODUCT_SEARCH_DEBOUNCE_MS,
  'aria-label': ariaLabel,
}: ProductSearchSelectProps) {
  const t = useT()
  const { locale } = useLocale()
  const preferFa = locale === 'fa'
  const [open, setOpen] = useState(false)
  const [query, setQuery] = useState('')
  const containerRef = useRef<HTMLDivElement>(null)
  const inputRef = useRef<HTMLInputElement>(null)
  const onQueryChangeRef = useRef(onQueryChange)
  onQueryChangeRef.current = onQueryChange

  const selected = options.find((option) => option.id === value)
  const selectedLabel = selected ? formatProductLabel(selected, preferFa) : ''
  const trimmedQuery = query.trim()
  const canSearch = trimmedQuery.length >= minSearchLength

  useEffect(() => {
    const cb = onQueryChangeRef.current
    if (!cb) return
    if (!canSearch) {
      cb('')
      return
    }
    const timer = window.setTimeout(() => cb(trimmedQuery), debounceMs)
    return () => window.clearTimeout(timer)
  }, [canSearch, trimmedQuery, debounceMs])

  const filtered = useMemo(() => {
    if (!canSearch) return []
    if (onQueryChange) return options
    const q = trimmedQuery.toLowerCase()
    return options.filter(
      (option) =>
        option.title.toLowerCase().includes(q) ||
        option.nameFa.includes(trimmedQuery),
    )
  }, [canSearch, onQueryChange, options, trimmedQuery])

  useEffect(() => {
    if (!open) return
    const onClickOutside = (e: MouseEvent) => {
      if (containerRef.current && !containerRef.current.contains(e.target as Node)) {
        setOpen(false)
        setQuery('')
      }
    }
    document.addEventListener('mousedown', onClickOutside)
    return () => document.removeEventListener('mousedown', onClickOutside)
  }, [open])

  function selectOption(id: string) {
    onChange(id)
    setOpen(false)
    setQuery('')
    onQueryChangeRef.current?.('')
  }

  function handleFocus() {
    if (!disabled) setOpen(true)
  }

  const showDropdown = open && (canSearch || trimmedQuery.length > 0)

  return (
    <div className={styles.wrapper} ref={containerRef} dir={preferFa ? 'rtl' : 'ltr'}>
      <div className={`${styles.inputWrap} ${open ? styles.inputWrapOpen : ''}`}>
        <Search size={16} className={styles.searchIcon} />
        <input
          ref={inputRef}
          id={id}
          type="text"
          className={styles.input}
          placeholder={selected ? selectedLabel : placeholder}
          value={open ? query : selectedLabel}
          onChange={(e) => {
            setQuery(e.target.value)
            if (!open) setOpen(true)
            if (value) onChange('')
          }}
          onFocus={handleFocus}
          disabled={disabled}
          aria-label={ariaLabel ?? placeholder}
          dir={preferFa ? 'rtl' : 'ltr'}
        />
        {value && !open && (
          <button
            type="button"
            className={styles.clearBtn}
            onClick={() => onChange('')}
            aria-label={t('storeItems.search.clear')}
          >
            <X size={14} />
          </button>
        )}
        {isSearching && open ? (
          <Loader2 size={16} className={`${styles.chevron} ${styles.spin}`} />
        ) : (
          <ChevronDown size={16} className={`${styles.chevron} ${open ? styles.chevronOpen : ''}`} />
        )}
      </div>

      {showDropdown && canSearch && (
        <ul className={`${styles.dropdown} ${styles.dropdownInFlow}`} role="listbox">
          {isSearching && filtered.length === 0 ? (
            <li className={styles.noResults}>{t('storeItems.search.searching')}</li>
          ) : filtered.length === 0 ? (
            <li className={styles.noResults}>{t('storeItems.search.noMatch')}</li>
          ) : (
            filtered.map((option) => (
              <li key={option.id}>
                <button
                  type="button"
                  role="option"
                  aria-selected={option.id === value}
                  className={`${styles.option} ${option.id === value ? styles.optionSelected : ''}`}
                  onClick={() => selectOption(option.id)}
                >
                  {preferFa && option.nameFa ? (
                    <>
                      <span className={styles.optionFa} dir="rtl">
                        {option.nameFa}
                      </span>
                      {option.title && (
                        <>
                          <span className={styles.optionSep}>/</span>
                          <span className={styles.optionEn} dir="rtl">
                            {option.title}
                          </span>
                        </>
                      )}
                    </>
                  ) : (
                    <>
                      <span className={styles.optionEn} dir={preferFa ? 'rtl' : 'ltr'}>
                        {option.title}
                      </span>
                      {option.nameFa && (
                        <>
                          <span className={styles.optionSep}>/</span>
                          <span className={styles.optionFa} dir="rtl">
                            {option.nameFa}
                          </span>
                        </>
                      )}
                    </>
                  )}
                </button>
              </li>
            ))
          )}
        </ul>
      )}

      {open && trimmedQuery.length > 0 && trimmedQuery.length < minSearchLength && (
        <ul className={`${styles.dropdown} ${styles.dropdownInFlow}`}>
          <li className={styles.noResults}>
            {t('storeItems.search.minChars', { count: minSearchLength })}
          </li>
        </ul>
      )}
    </div>
  )
}