// components/ShareLinkButton.tsx
// Renders the public onboarding URL with a native-share / copy-to-clipboard
// affordance. On mobile we use navigator.share() so the user can fire the
// link off via WhatsApp / SMS / email / any installed share target. On
// desktop (or any browser without navigator.share) we fall back to a
// "Copy link" button. After success we show a transient confirmation
// ("Copied" / "Sent") for ~2s and then revert to the original label.

"use client";

import { useEffect, useState } from "react";

type ShareState = "idle" | "copied" | "shared" | "error";

interface Props {
  /** The full URL the user should send to the client. */
  url: string;
  /** Optional share-sheet title. Defaults to "Workflow onboarding link". */
  title?: string;
  /** Optional one-liner that ships in the share sheet body where
   *  the platform supports it. */
  text?: string;
}

export default function ShareLinkButton({
  url,
  title = "Workflow onboarding link",
  text = "Please complete your company and director information using this secure link:"
}: Props) {
  const [state, setState] = useState<ShareState>("idle");
  const [canNativeShare, setCanNativeShare] = useState(false);

  useEffect(() => {
    // navigator.share is mobile-first; some desktop browsers have it
    // behind a flag. We render the native button optimistically when
    // present (the type narrowing avoids SSR-mismatch issues since
    // we only set the flag in an effect).
    if (
      typeof navigator !== "undefined" &&
      typeof navigator.share === "function"
    ) {
      setCanNativeShare(true);
    }
  }, []);

  async function copyToClipboard() {
    try {
      // Modern path with Clipboard API; falls back to the legacy
      // textarea-trick if the secure API isn't allowed (HTTP context).
      if (navigator.clipboard?.writeText) {
        await navigator.clipboard.writeText(url);
      } else {
        const ta = document.createElement("textarea");
        ta.value = url;
        ta.setAttribute("readonly", "");
        ta.style.position = "fixed";
        ta.style.opacity = "0";
        document.body.appendChild(ta);
        ta.select();
        document.execCommand("copy");
        document.body.removeChild(ta);
      }
      setState("copied");
    } catch {
      setState("error");
    }
    window.setTimeout(() => setState("idle"), 1800);
  }

  async function shareNative() {
    try {
      await navigator.share({ url, title, text });
      setState("shared");
    } catch (err) {
      // User-cancelled share is NOT an error — silent revert.
      if ((err as DOMException)?.name === "AbortError") {
        setState("idle");
        return;
      }
      setState("error");
    }
    window.setTimeout(() => setState("idle"), 1800);
  }

  const label =
    state === "copied"
      ? "Copied ✓"
      : state === "shared"
        ? "Sent ✓"
        : state === "error"
          ? "Try again"
          : canNativeShare
            ? "Share link"
            : "Copy link";

  return (
    <div className="flex flex-wrap items-center gap-3">
      <button
        type="button"
        onClick={canNativeShare ? shareNative : copyToClipboard}
        className={
          "inline-flex items-center gap-2 px-4 py-2 rounded-md text-sm font-semibold no-underline transition-colors " +
          (state === "error"
            ? "bg-danger text-accent-on"
            : "bg-accent text-accent-on hover:bg-accent-hover")
        }
        aria-live="polite"
      >
        <IconShare className="w-4 h-4" />
        <span>{label}</span>
      </button>
      <a
        href={url}
        target="_blank"
        rel="noopener noreferrer"
        className="text-sm font-semibold text-fg hover:underline"
      >
        Open link ↗
      </a>
    </div>
  );
}

function IconShare({ className }: { className?: string }) {
  return (
    <svg
      viewBox="0 0 24 24"
      fill="none"
      stroke="currentColor"
      strokeWidth={1.8}
      strokeLinecap="round"
      strokeLinejoin="round"
      className={className}
      aria-hidden="true"
    >
      <circle cx="6" cy="12" r="2.4" />
      <circle cx="18" cy="6" r="2.4" />
      <circle cx="18" cy="18" r="2.4" />
      <path d="M8.1 11l7.8-4M8.1 13l7.8 4" />
    </svg>
  );
}