"use client";

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

const Form = FormProvider;

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

const FormFieldContext = React.createContext<FormFieldContextValue>(
  {} as FormFieldContextValue
);

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 }>({ id: "" });

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

  if (!fieldContext.name) {
    throw new Error("useFormField must be used within <FormField>");
  }

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

function FormItem({ className, ...props }: React.HTMLAttributes<HTMLDivElement>) {
  const id = React.useId();
  return (
    <FormItemContext.Provider value={{ id }}>
      <div className={cn("space-y-2", className)} {...props} />
    </FormItemContext.Provider>
  );
}

function FormLabel({
  className,
  ...props
}: React.ComponentProps<typeof Label>) {
  const { error, formItemId } = useFormField();
  return (
    <Label
      className={cn(error && "text-destructive", className)}
      htmlFor={formItemId}
      {...props}
    />
  );
}

function FormControl({ ...props }: React.ComponentPropsWithoutRef<typeof Slot.Root>) {
  const { error, formItemId, formDescriptionId, formMessageId } = useFormField();
  return (
    <Slot.Root
      id={formItemId}
      aria-describedby={
        !error ? formDescriptionId : `${formDescriptionId} ${formMessageId}`
      }
      aria-invalid={!!error}
      {...props}
    />
  );
}

function FormDescription({
  className,
  ...props
}: React.HTMLAttributes<HTMLParagraphElement>) {
  const { formDescriptionId } = useFormField();
  return (
    <p
      id={formDescriptionId}
      className={cn("text-sm text-muted-foreground", className)}
      {...props}
    />
  );
}

function FormMessage({
  className,
  children,
  ...props
}: React.HTMLAttributes<HTMLParagraphElement>) {
  const { error, formMessageId } = useFormField();
  const body = error ? String(error?.message ?? "") : children;

  if (!body) return null;

  return (
    <p
      id={formMessageId}
      className={cn(
        "font-[family-name:var(--mono)] text-[10px] tracking-[0.12em] uppercase text-destructive",
        className
      )}
      {...props}
    >
      {body}
    </p>
  );
}

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