import { Combobox } from "@headlessui/react";

import { DropDownItem } from "@shared/nej-react-components/Parts/DropDown";
import { useEffect, useRef, useState } from "react";

import tw from "twin.macro";
import "styled-components/macro";
import { useField } from "@shared/nej-react-components/Parts/Input";
import { FieldHookConfig } from "formik";

type Option<T> = string | { value: T, label: string };
type RenderOption<T> = (item: Option<T>, state: { active: boolean, selected: boolean }) => JSX.Element;

export function AutocompleteSelect<T>({ title, titleProps = null, data, nullable = false, renderOption = undefined, onScrollEnd = undefined, onQueryChange = undefined, ...props }:
  FieldHookConfig<T> &
  ({ title: string, titleProps?: any, data: Option<T>[] | ((query: string) => Promise<Option<T>[]>), nullable?: boolean, renderOption?: RenderOption<T>, onScrollEnd?: () => void, onQueryChange?: (query: string) => void } |
  { title: string, titleProps?: any, data: Record<string, string>, nullable?: boolean, renderOption?: RenderOption<string>, onScrollEnd?: () => void, onQueryChange?: (query: string) => void })
) {
  const [field, meta, helpers] = useField<T>(props);

  const [query, setQuery] = useState(field.value as string ?? "");
  const [internalData, setInternalData] = useState<Option<T>[]>([]);
  const sentinelRef = useRef(null);

  useEffect(() => {
    if (!onScrollEnd || !sentinelRef.current) return;
    const observer = new IntersectionObserver(
      (entries) => { if (entries[0].isIntersecting) onScrollEnd(); },
      { threshold: 0.1 }
    );
    observer.observe(sentinelRef.current);
    return () => observer.disconnect();
  }, [onScrollEnd]);

  useEffect(() => {
    (async () => {
      if (typeof data === "function") {
        //if data is async function await it
        setInternalData(await data(query));
      } else if (Array.isArray(data)) {
        // When renderOption is provided the caller manages filtering externally, just show data as-is
        if (renderOption) {
          setInternalData(data);
        } else {
          setInternalData(
            query === ""
              ? data
              : data.filter((item) => {
                if (typeof item === "string")
                  return item.toLowerCase().includes(query.toLowerCase());

                return item.label.toLowerCase().includes(query.toLowerCase());
              })
          );
        }
      } else if (typeof data === "object") {
        // TypeScript enum objects — convert values to { value, label } then filter
        const enumItems = Object.values(data).map((value) => ({ value, label: value }));
        setInternalData(
          !renderOption && query !== ""
            ? enumItems.filter((item) => String(item.label).toLowerCase().includes(query.toLowerCase()))
            : enumItems as any
        );
      }
      else {
        console.error("data is not an array or function :c");
        setInternalData([]);
      }
    })();
  }, [query, data]);

  return <>
    <Combobox<Option<T>>
      {...props as any}
      {...field}
      value={
        field.value
          ? internalData?.filter((item) =>
            typeof item === "string"
              ? item == field.value
              : item.value === field.value
          )[0]
          : null
      }
      onChange={(value) => {
        // If value is an object (from internalData lookup), store only the primitive .value
        if (Array.isArray(value)) {
          const stored = value.map((v) => (typeof v === "string" ? v : v.value));
          field.onChange({ target: { value: stored, name: field.name } });
        } else {
          const stored = value != null && typeof value === "object" ? (value as any).value  : value;
          field.onChange({ target: { value: stored, name: field.name } });
        }
      }
      }
      nullable={nullable as any}
    >
      <div css={[title && tw`my-1`, tw`relative`]} >
        {title && (
          <label
            {...titleProps}
            css={
              [
                tw`block text-secondary text-sm font-bold mb-2`,
                titleProps?.css,
              ]}
          >
            {title}
          </label>
        )}
        <div tw="relative" >
          <Combobox.Input<Option<T>>
            tw="bg-primary cursor-pointer appearance-none border-2 border-secondary rounded w-full py-2 px-4 text-primary leading-tight focus:outline-none focus:bg-secondary focus:border-accent transition duration-150 "
            onChange={(event) => { setQuery(event.target.value); onQueryChange?.(event.target.value); }}
            displayValue={(val) => (typeof val === "string" ? val : val?.label)}
          />
          < Combobox.Button tw="absolute top-0 right-0 left-0 bottom-0 " />
        </div>
        < Combobox.Options tw="absolute z-10 max-h-60 w-full bg-trinary rounded-xl overflow-y-auto overflow-x-hidden" >
          {internalData?.map((val) => (
            <Combobox.Option
              tw=""
              key={typeof val === "string" ? val : val.label}
              value={typeof val === "string" ? val : val.value}
            >
              {
                renderOption ? (state) => renderOption(val as any, state)
                  : <DropDownItem>{typeof val === "string" ? val : val.label} </DropDownItem>
              }
            </Combobox.Option>
          ))}
          {onScrollEnd && <div ref={sentinelRef} />}
        </Combobox.Options>
      </div>
    </Combobox>

    {
      meta?.touched && meta.error ? (
        <div tw="text-[#c23c3c]" > {meta.error} </div>
      ) : null
    }
  </>;
}