"use client"
import { da, de, fi, nb, sv } from "date-fns/locale"
import { useCallback, useEffect, useRef, useState } from "react"
import { useFormContext, useWatch } from "react-hook-form"

import { Lang } from "@/constants/languages"
import { dt } from "@/lib/dt"

import Body from "@/components/TempDesignSystem/Text/Body"
import useLang from "@/hooks/useLang"

import DatePickerDesktop from "./Screen/Desktop"
import DatePickerMobile from "./Screen/Mobile"

import styles from "./date-picker.module.css"

import type { DatePickerFormProps } from "@/types/components/datepicker"

const locales = {
  [Lang.da]: da,
  [Lang.de]: de,
  [Lang.fi]: fi,
  [Lang.no]: nb,
  [Lang.sv]: sv,
}

export default function DatePickerForm({ name = "date" }: DatePickerFormProps) {
  const lang = useLang()
  const [isOpen, setIsOpen] = useState(false)
  const selectedDate = useWatch({ name })
  const { register, setValue } = useFormContext()
  const ref = useRef<HTMLDivElement | null>(null)

  const [isSelectingFrom, setIsSelectingFrom] = useState(true)

  function close() {
    setIsOpen(false)
  }

  function showOnFocus() {
    setIsOpen(true)
  }

  function handleSelectDate(selected: Date) {
    /* check if selected date is not before todays date,
     which happens when "Enter" key is pressed in any other input field of the form */
    if (!dt(selected).isBefore(dt(), "day")) {
      if (isSelectingFrom) {
        setValue(name, {
          fromDate: dt(selected).format("YYYY-MM-DD"),
          toDate: undefined,
        })
        setIsSelectingFrom(false)
      } else if (!dt(selectedDate.fromDate).isSame(dt(selected))) {
        const fromDate = dt(selectedDate.fromDate)
        const toDate = dt(selected)
        if (toDate.isAfter(fromDate)) {
          setValue(name, {
            fromDate: selectedDate.fromDate,
            toDate: toDate.format("YYYY-MM-DD"),
          })
        } else {
          setValue(name, {
            fromDate: toDate.format("YYYY-MM-DD"),
            toDate: selectedDate.fromDate,
          })
        }
        setIsSelectingFrom(true)
      }
    }
  }
  const closeIfOutside = useCallback(
    (target: HTMLElement) => {
      if (ref.current && target && !ref.current.contains(target)) {
        if (!selectedDate.toDate) {
          setValue(name, {
            fromDate: selectedDate.fromDate,
            toDate: dt(selectedDate.fromDate)
              .add(1, "day")
              .format("YYYY-MM-DD"),
          })
          setIsSelectingFrom(true)
        }
        setIsOpen(false)
      }
    },
    [setIsOpen, setValue, setIsSelectingFrom, selectedDate, name, ref]
  )

  function closeOnBlur(evt: FocusEvent) {
    if (isOpen) {
      const target = evt.relatedTarget as HTMLElement
      closeIfOutside(target)
    }
  }

  useEffect(() => {
    function handleClickOutside(evt: Event) {
      if (isOpen) {
        const target = evt.target as HTMLElement
        closeIfOutside(target)
      }
    }
    document.body.addEventListener("click", handleClickOutside)
    return () => {
      document.body.removeEventListener("click", handleClickOutside)
    }
  }, [closeIfOutside, isOpen])

  const selectedFromDate = dt(selectedDate.fromDate)
    .locale(lang)
    .format("ddd D MMM")
  const selectedToDate = !!selectedDate.toDate
    ? dt(selectedDate.toDate).locale(lang).format("ddd D MMM")
    : ""

  return (
    <div
      className={styles.container}
      onBlur={(e) => {
        closeOnBlur(e.nativeEvent)
      }}
      data-isopen={isOpen}
      ref={ref}
    >
      <button className={styles.btn} onFocus={showOnFocus} type="button">
        <Body className={styles.body} asChild>
          <span>
            {selectedFromDate} - {selectedToDate}
          </span>
        </Body>
      </button>
      <input {...register("date.fromDate")} type="hidden" />
      <input {...register("date.toDate")} type="hidden" />
      <div aria-modal className={styles.hideWrapper} role="dialog">
        <DatePickerDesktop
          close={close}
          handleOnSelect={handleSelectDate}
          locales={locales}
          // DayPicker lib needs Daterange in form as below to show appropriate UI
          selectedDate={{
            from: selectedDate.fromDate,
            to: selectedDate.toDate,
          }}
        />
        <DatePickerMobile
          close={close}
          handleOnSelect={handleSelectDate}
          locales={locales}
          // DayPicker lib needs Daterange in form as below to show appropriate UI
          selectedDate={{
            from: selectedDate.fromDate,
            to: selectedDate.toDate,
          }}
        />
      </div>
    </div>
  )
}
