"use client"

import * as React from "react"
import { Slot } from "radix-ui"
import {
  Controller,
  FormProvider,
  useFormContext,
  type ControllerProps,
  type FieldPath,
  type FieldValues,
} from "react-hook-form"

import { cn } from "../../lib/utils"
import { Label } from "./label"

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>) {
  const fieldContextValue = React.useMemo(
    () => ({ name: props.name }),
    [props.name],
  )
  return (
    <FormFieldContext.Provider value={fieldContextValue}>
      <Controller {...props} />
    </FormFieldContext.Provider>
  )
}

function useFormField() {
  const fieldContext = React.useContext(FormFieldContext)
  const itemContext  = React.useContext(FormItemContext)
  const formContext = useFormContext()

  if (!fieldContext) {
    throw new Error("useFormField must be used inside <FormField>")
  }
  if (!itemContext) {
    throw new Error("useFormField must be used inside <FormItem>")
  }
  if (!formContext) {
    throw new Error("useFormField must be used inside <Form>")
  }

  const { getFieldState, formState } = formContext
  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,
  }
}

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

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

function FormLabel({
  className,
  onClick,
  ...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-ink", className)}
      htmlFor={formItemId}
      onClick={(event) => {
        onClick?.(event)
        if (event.defaultPrevented) return
        const target = document.getElementById(formItemId)
        const isNativeLabelTarget = target?.matches(
          "button, input, meter, output, progress, select, textarea",
        )
        if (target && !isNativeLabelTarget) target.focus()
      }}
      {...props}
    />
  )
}

function FormControl({ ...props }: React.ComponentProps<typeof Slot.Root>) {
  const { error, formItemId, formDescriptionId, formMessageId } = useFormField()
  return (
    <Slot.Root
      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-sm", className)}
      {...props}
    />
  )
}

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

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