"use client"

import { useActionState, useEffect, useId, useRef } from "react"
import { CircleAlert, CircleCheck } from "lucide-react"

import { Button, ButtonArrow } from "@/components/ui/button"
import { Input } from "@/components/ui/input"
import { Label } from "@/components/ui/label"
import { Textarea } from "@/components/ui/textarea"
import { play } from "@/lib/sound"
import { cn } from "@/lib/utils"
import { CONTACT_PREFILL_EVENT } from "@/modules/landingPage/lib/contact-prefill"
import {
  initialContactState,
  type ContactField,
} from "@/modules/landingPage/schema/contact-schema"
import { submitContact } from "@/modules/landingPage/server/contact-action"

export function ContactForm() {
  const [state, formAction, pending] = useActionState(
    submitContact,
    initialContactState
  )
  const id = useId()
  const messageRef = useRef<HTMLTextAreaElement>(null)

  useEffect(() => {
    if (state.status === "success") play("confirm")
  }, [state])

  // Text handed over by other sections, e.g. the price calculator
  useEffect(() => {
    const onPrefill = (event: Event) => {
      const el = messageRef.current
      if (!el) return
      const text = (event as CustomEvent<string>).detail
      // Keep whatever the visitor already wrote
      el.value = el.value.trim() ? `${text}

${el.value}` : text
      // The page is still scrolling there, so focus without jumping
      el.focus({ preventScroll: true })
      el.setSelectionRange(el.value.length, el.value.length)
    }
    window.addEventListener(CONTACT_PREFILL_EVENT, onPrefill)
    return () => window.removeEventListener(CONTACT_PREFILL_EVENT, onPrefill)
  }, [])

  const fieldId = (field: ContactField) => `${id}-${field}`
  const errorId = (field: ContactField) => `${id}-${field}-error`
  const errorFor = (field: ContactField) => state.fieldErrors?.[field]?.[0]

  // Wires label, error text and aria attributes together for one field
  const fieldProps = (field: ContactField) => ({
    id: fieldId(field),
    name: field,
    "aria-invalid": errorFor(field) ? true : undefined,
    "aria-describedby": errorFor(field) ? errorId(field) : undefined,
  })

  if (state.status === "success") {
    return (
      <div role="status" className="flex flex-col items-start gap-4 py-8">
        <CircleCheck className="size-8 text-signal-success" aria-hidden />
        <p className="text-title font-heading">{state.message}</p>
        <p className="type-body text-fg-muted">
          Du bekommst eine Antwort von einem Menschen, nicht von einem Ticketsystem.
        </p>
      </div>
    )
  }

  return (
    <form action={formAction} noValidate className="grid gap-6 sm:grid-cols-2">
      <Field id={errorId("name")} message={errorFor("name")}>
        <Label htmlFor={fieldId("name")}>Name</Label>
        <Input
          {...fieldProps("name")}
          autoComplete="name"
          required
          defaultValue={state.values?.name}
        />
      </Field>

      <Field id={errorId("email")} message={errorFor("email")}>
        <Label htmlFor={fieldId("email")}>E-Mail</Label>
        <Input
          {...fieldProps("email")}
          type="email"
          autoComplete="email"
          required
          defaultValue={state.values?.email}
        />
      </Field>

      <Field
        id={errorId("company")}
        message={errorFor("company")}
        className="sm:col-span-2"
      >
        <Label htmlFor={fieldId("company")}>
          Unternehmen <span className="text-fg-muted">(optional)</span>
        </Label>
        <Input
          {...fieldProps("company")}
          autoComplete="organization"
          defaultValue={state.values?.company}
        />
      </Field>

      <Field
        id={errorId("message")}
        message={errorFor("message")}
        className="sm:col-span-2"
      >
        <Label htmlFor={fieldId("message")}>Worum geht es?</Label>
        <Textarea
          {...fieldProps("message")}
          ref={messageRef}
          required
          rows={5}
          defaultValue={state.values?.message}
        />
      </Field>

      {/* Honeypot, hidden from people and assistive technology */}
      <div aria-hidden="true" className="absolute -left-[9999px] h-px w-px overflow-hidden">
        <label>
          Website
          <input type="text" name="website" tabIndex={-1} autoComplete="off" />
        </label>
      </div>

      <Field
        id={errorId("privacy")}
        message={errorFor("privacy")}
        className="sm:col-span-2"
      >
        <div className="flex items-start gap-3">
          <input
            {...fieldProps("privacy")}
            type="checkbox"
            required
            defaultChecked={state.values?.privacy}
            className="mt-0.5 size-5 shrink-0 accent-current"
          />
          <label htmlFor={fieldId("privacy")} className="text-sm text-fg-muted">
            Ich bin einverstanden, dass meine Angaben zur Bearbeitung der Anfrage
            gespeichert werden. Details in der{" "}
            <a href="/datenschutz" className="text-fg underline underline-offset-4">
              Datenschutzerklärung
            </a>
            .
          </label>
        </div>
      </Field>

      <div className="flex flex-col items-start gap-4 sm:col-span-2 sm:flex-row sm:items-center">
        <Button type="submit" size="lg" disabled={pending}>
          {pending ? "Wird gesendet …" : "Anfrage senden"}
          <ButtonArrow />
        </Button>
        <p aria-live="polite" className="text-sm text-signal-error">
          {state.status === "error" ? state.message : null}
        </p>
      </div>
    </form>
  )
}

function Field({
  id,
  message,
  className,
  children,
}: {
  id: string
  message?: string
  className?: string
  children: React.ReactNode
}) {
  return (
    <div className={cn("flex flex-col gap-2.5", className)}>
      {children}
      {/* Errors are shown in text and color, never color alone */}
      {message ? (
        <p id={id} className="flex items-center gap-1.5 text-sm text-signal-error">
          <CircleAlert className="size-4 shrink-0" aria-hidden />
          {message}
        </p>
      ) : null}
    </div>
  )
}