"use client";

import * as React from "react";
import {
  Controller,
  FormProvider,
  useFormContext,
  useFormState,
  type ControllerProps,
  type FieldPath,
  type FieldValues,
} from "react-hook-form";
import { Label } from "@/components/ui/label";
import { cn } from "@/lib/utils";

const Form = FormProvider;

interface FormFieldContextValue<
  TFieldValues extends FieldValues = FieldValues,
  TName extends FieldPath<TFieldValues> = FieldPath<TFieldValues>,
> {
  name: TName;
}

const FormFieldContext = React.createContext<FormFieldContextValue | null>(
  null,
);

function FormField<
  TFieldValues extends FieldValues = FieldValues,
  TName extends FieldPath<TFieldValues> = FieldPath<TFieldValues>,
>(props: ControllerProps<TFieldValues, TName>) {
  return (
    <FormFieldContext.Provider value={{ name: props.name }}>
      <Controller {...props} />
    </FormFieldContext.Provider>
  );
}

const FormItemContext = React.createContext<{ id: string } | null>(null);

function useFormField() {
  const fieldContext = React.useContext(FormFieldContext);
  const itemContext = React.useContext(FormItemContext);
  const { getFieldState } = useFormContext();
  const formState = useFormState({ name: fieldContext?.name });

  if (!fieldContext || !itemContext)
    throw new Error("useFormField must be used within <FormItem>/<FormField>");

  const fieldState = getFieldState(fieldContext.name, formState);
  const { id } = itemContext;

  return {
    id,
    name: fieldContext.name,
    formItemId: `${id}-form-item`,
    formDescriptionId: `${id}-form-item-description`,
    formMessageId: `${id}-form-item-message`,
    ...fieldState,
  };
}

function FormItem({ className, ...props }: React.ComponentProps<"div">) {
  const id = React.useId();
  return (
    <FormItemContext.Provider value={{ id }}>
      <div
        data-slot="form-item"
        className={cn("flex flex-col gap-1.5", className)}
        {...props}
      />
    </FormItemContext.Provider>
  );
}

function FormLabel({
  className,
  ...props
}: React.ComponentProps<typeof Label>) {
  const { error, formItemId } = useFormField();
  return (
    <Label
      data-slot="form-label"
      data-error={!!error}
      className={cn("data-[error=true]:text-destructive", className)}
      htmlFor={formItemId}
      {...props}
    />
  );
}

function FormControl({ ...props }: React.ComponentProps<"div">) {
  const { error, formItemId, formDescriptionId, formMessageId } =
    useFormField();
  return (
    <div
      data-slot="form-control"
      id={formItemId}
      aria-describedby={
        !error ? formDescriptionId : `${formDescriptionId} ${formMessageId}`
      }
      aria-invalid={!!error}
      {...props}
    />
  );
}

function FormDescription({ className, ...props }: React.ComponentProps<"p">) {
  const { formDescriptionId } = useFormField();
  return (
    <p
      data-slot="form-description"
      id={formDescriptionId}
      className={cn("text-muted-foreground text-xs", className)}
      {...props}
    />
  );
}

function FormMessage({ className, ...props }: React.ComponentProps<"p">) {
  const { error, formMessageId } = useFormField();
  const body = error ? String(error?.message ?? "") : props.children;
  if (!body) return null;
  return (
    <p
      data-slot="form-message"
      id={formMessageId}
      className={cn("text-destructive text-xs font-medium", className)}
      {...props}
    >
      {body}
    </p>
  );
}

export {
  useFormField,
  Form,
  FormItem,
  FormLabel,
  FormControl,
  FormDescription,
  FormMessage,
  FormField,
};