"use client";

import { onContactTopic } from "./contactTopic";
import * as React from "react";
import { useContent } from "@/src/components/ContentProvider";
import { CONTACT_EMAIL_PARTS } from "@/src/content/site";
import { assembleEmail, mailtoHref, spellOutEmail } from "@/src/domain/email";

const TYPE_MS = 9;
const MONO = "font-mono text-[11px] uppercase tracking-[0.2em]";

/** The text typed out so far. Jumps to the full text when motion is reduced. */
const useTyped = (text: string): string => {
  const [length, setLength] = React.useState(text.length);

  React.useEffect(() => {
    if (window.matchMedia("(prefers-reduced-motion: reduce)").matches) {
      setLength(text.length);
      return;
    }
    setLength(0);
    const timer = window.setInterval(() => {
      setLength((current) => {
        if (current >= text.length) {
          window.clearInterval(timer);
          return current;
        }
        return Math.min(text.length, current + 3);
      });
    }, TYPE_MS);
    return () => window.clearInterval(timer);
  }, [text]);

  return text.slice(0, length);
};

/** Blanks the visitor fills in are set apart from the prepared wording. */
const withBlanks = (text: string): React.ReactNode =>
  text.split(/(\[[^\]]*\]?)/).map((part, index) =>
    part.startsWith("[") ? (
      <span key={index} className="rounded-sm bg-amber-200/15 text-amber-200">
        {part}
      </span>
    ) : (
      part
    ),
  );

/**
 * ContactComposer: pick what you need and the email writes itself. One press
 * opens it in the visitor's own mail app, ready to finish and send. The address
 * is assembled in the browser, so it never appears in the page source.
 */
export const ContactComposer: React.FC = () => {
  const { contact } = useContent();
  const topics = contact.topics;
  const [topicId, setTopicId] = React.useState(topics[0]?.id ?? "");
  const [address, setAddress] = React.useState<string | null>(null);
  const [copied, setCopied] = React.useState(false);

  React.useEffect(() => {
    setAddress(assembleEmail(CONTACT_EMAIL_PARTS));
  }, []);

  // A button elsewhere on the page can open the message with its topic chosen.
  React.useEffect(
    () =>
      onContactTopic((id) => {
        if (topics.some((item) => item.id === id)) setTopicId(id);
      }),
    [topics],
  );

  const topic = topics.find((item) => item.id === topicId) ?? topics[0];
  const typed = useTyped(topic?.draft.body ?? "");

  if (!topic) return null;

  const done = typed.length === topic.draft.body.length;

  const copy = async () => {
    if (!address) return;
    try {
      await navigator.clipboard.writeText(address);
      setCopied(true);
      window.setTimeout(() => setCopied(false), 1800);
    } catch {
      // Clipboard access can be refused; the address stays visible to copy by hand.
    }
  };

  return (
    <div className="overflow-hidden rounded-3xl border border-slate-700 bg-slate-950/60 backdrop-blur-sm">
      <div className="flex items-center justify-between border-b border-slate-800 px-5 py-4 md:px-7">
        <div className="flex items-center gap-3">
          <span className="flex gap-1.5" aria-hidden="true">
            <span className="h-2.5 w-2.5 rounded-full bg-slate-700" />
            <span className="h-2.5 w-2.5 rounded-full bg-slate-700" />
            <span className="h-2.5 w-2.5 rounded-full bg-slate-700" />
          </span>
          <span className={`${MONO} text-slate-400`}>{contact.newMessage}</span>
        </div>
        <span className={`${MONO} flex items-center gap-2 text-slate-500`}>
          <span className="h-1.5 w-1.5 animate-pulse rounded-full bg-emerald-400" />
          {contact.draft}
        </span>
      </div>

      <div className="border-b border-slate-800 px-5 py-5 md:px-7">
        <p className={`${MONO} m-0 text-slate-500`}>{contact.need}</p>
        <div className="mt-3 flex flex-wrap gap-2">
          {topics.map((item) => {
            const selected = item.id === topic.id;
            return (
              <button
                key={item.id}
                type="button"
                aria-pressed={selected}
                onClick={() => setTopicId(item.id)}
                className={`rounded-full border px-4 py-2 font-mono text-[11px] uppercase tracking-[0.15em] transition-colors duration-200 ${
                  selected
                    ? "border-white bg-white text-slate-900"
                    : "border-slate-700 text-slate-300 hover:border-slate-400 hover:text-white"
                }`}
              >
                {item.label}
              </button>
            );
          })}
        </div>
      </div>

      <dl className="m-0 border-b border-slate-800 px-5 py-4 font-mono text-[12px] leading-relaxed md:px-7 md:text-[13px]">
        <div className="flex gap-4">
          <dt className="w-16 shrink-0 text-slate-500">{contact.to}</dt>
          <dd className="m-0 select-all text-slate-200">
            {address ?? spellOutEmail(CONTACT_EMAIL_PARTS)}
          </dd>
        </div>
        <div className="mt-1 flex gap-4">
          <dt className="w-16 shrink-0 text-slate-500">{contact.subject}</dt>
          <dd className="m-0 text-white">{topic.draft.subject}</dd>
        </div>
      </dl>

      <div
        className="min-h-[15.5rem] whitespace-pre-wrap px-5 py-5 font-mono text-[12px] leading-relaxed text-slate-300 md:min-h-[14rem] md:px-7 md:text-[13px]"
        aria-live="off"
      >
        {withBlanks(typed)}
        <span
          aria-hidden="true"
          className={`ml-0.5 inline-block h-[1.05em] w-[0.55em] translate-y-[0.18em] bg-amber-200 ${done ? "animate-pulse" : ""}`}
        />
      </div>

      <div className="flex flex-col gap-3 border-t border-slate-800 p-5 sm:flex-row sm:items-center md:px-7">
        <a
          href={
            address ? mailtoHref(CONTACT_EMAIL_PARTS, topic.draft) : "#contact"
          }
          className="bit-cta bit-cta-light group inline-flex flex-1 items-center justify-between gap-4 rounded-full bg-white px-7 py-4 font-sans text-[12px] font-bold uppercase tracking-[0.18em] text-slate-900 no-underline transition-transform duration-300 hover:-translate-y-0.5"
        >
          {contact.open}
          <span
            aria-hidden="true"
            className="transition-transform duration-300 group-hover:translate-x-1"
          >
            →
          </span>
        </a>
        <button
          type="button"
          onClick={copy}
          className="rounded-full border border-slate-700 px-6 py-4 font-sans text-[12px] font-bold uppercase tracking-[0.18em] text-slate-300 transition-colors duration-200 hover:border-slate-400 hover:text-white"
        >
          {copied ? contact.copied : contact.copy}
        </button>
      </div>
    </div>
  );
};