/**
 * @file OnboardingTour.tsx
 * @description The step-by-step spotlight tour after the first-run setup
 * (docs/plans/onboarding): it dims the page around ONE real control and says
 * what to do with it — Add workspace → the folder → Add → the prompt box →
 * the live session → done. The overlay never takes a click (the user works
 * the real UI); a step moves on when what it asked for has happened (the
 * dialog opened, the workspace exists, the session started), and steps back
 * when the user backed out (the dialog closed with nothing made). Targets are
 * existing `data-testid`s plus `data-tour` marks in AddLaneModal and
 * FolderBrowseModal. The
 * step reached is `localStorage["agenthub.tour"]`, so it is synced to the
 * account and survives a reload; `done` ends it.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

import { useEffect, useState } from "react";
import { createPortal } from "react-dom";
import { useTranslation } from "react-i18next";
import { useLocation, useNavigate } from "react-router-dom";

const KEY = "agenthub.tour";
const EVENT = "agenthub-tour";
const POLL_MS = 250;

type StepId = "add" | "folder" | "create" | "prompt" | "session" | "finish";
const ORDER: StepId[] = ["add", "folder", "create", "prompt", "session", "finish"];

const $ = (sel: string) => document.querySelector(sel);
/** An element that is on screen (a console collapsed with CSS has no box). */
function shown(sel: string): Element | null {
  const el = $(sel);
  if (!el) return null;
  const r = el.getBoundingClientRect();
  return r.width > 0 && r.height > 0 ? el : null;
}

const modalOpen = () => !!$('[data-tour="add-lane"]');
const composer = () => shown('[data-testid="workspace-home-composer"]');
const sessionLive = () =>
  !!new URLSearchParams(window.location.search).get("run") && !!shown('[data-testid="pane-grid"]');

/** Where each step points, and what moves it on (or back). */
const STEPS: Record<
  StepId,
  { target: () => Element | null; next?: () => StepId | null; info?: boolean }
> = {
  add: {
    // The sidebar's +; folded to a rail, its tree icon (which unfolds it).
    target: () =>
      shown('[data-testid="workspace-tree-add"]') || shown('[data-testid="sidebar-tree-rail"]'),
    next: () => (modalOpen() ? "folder" : null),
  },
  folder: {
    // The folder browser while it is open: it sits over the field.
    target: () => $('[data-tour="folder-browse"]') || $('[data-tour="add-lane-folder"]'),
    next: () => (modalOpen() ? null : composer() ? "prompt" : "add"),
    info: true,
  },
  create: {
    target: () => $('[data-tour="add-lane-create"]'),
    next: () => (modalOpen() ? null : composer() ? "prompt" : "add"),
  },
  prompt: {
    target: composer,
    next: () => (sessionLive() ? "session" : null),
  },
  session: { target: () => shown('[data-testid="pane-grid"]'), info: true },
  finish: { target: () => null, info: true },
};

function read(): StepId | null {
  try {
    const v = localStorage.getItem(KEY);
    return (ORDER as string[]).includes(v ?? "") ? (v as StepId) : null;
  } catch {
    return null;
  }
}
function write(v: StepId | "done") {
  try {
    localStorage.setItem(KEY, v);
  } catch {
    /* storage blocked: the tour just ends with the page */
  }
  window.dispatchEvent(new Event(EVENT));
}

/** Begin the tour at its first step (the setup's last button). */
export const startTour = () => write("add");

/** Mounted once in the layout; renders nothing unless a tour is running. */
export function OnboardingTour() {
  const { t } = useTranslation("onboarding");
  const navigate = useNavigate();
  const location = useLocation();
  const [step, setStep] = useState<StepId | null>(read);
  const [rect, setRect] = useState<DOMRect | null>(null);
  // The dialog the target sits in, if any: the card goes beside the dialog.
  const [box, setBox] = useState<DOMRect | null>(null);

  useEffect(() => {
    const sync = () => setStep(read());
    window.addEventListener(EVENT, sync);
    window.addEventListener("storage", sync);
    return () => {
      window.removeEventListener(EVENT, sync);
      window.removeEventListener("storage", sync);
    };
  }, []);

  useEffect(() => {
    if (!step) return;
    const tick = () => {
      const def = STEPS[step];
      const moved = def.next?.();
      if (moved && moved !== step) return write(moved);
      const el = def.target();
      let r = el ? el.getBoundingClientRect() : null;
      // The folder field's suggestions hang below it: light them too.
      const list = el?.querySelector("[data-cwd-suggestions]")?.getBoundingClientRect();
      if (r && list) {
        const top = Math.min(r.top, list.top);
        const left = Math.min(r.left, list.left);
        r = new DOMRect(
          left,
          top,
          Math.max(r.right, list.right) - left,
          Math.max(r.bottom, list.bottom) - top
        );
      }
      const d = el?.closest("[role=dialog]")?.getBoundingClientRect() ?? null;
      setBox((prev) => (prev && d && prev.right === d.right ? prev : d));
      // Only when it moved: a new DOMRect every tick would re-render forever.
      setRect((prev) =>
        prev &&
        r &&
        prev.x === r.x &&
        prev.y === r.y &&
        prev.width === r.width &&
        prev.height === r.height
          ? prev
          : r
      );
    };
    tick();
    const id = window.setInterval(tick, POLL_MS);
    return () => window.clearInterval(id);
  }, [step, location]);

  if (!step) return null;
  const n = ORDER.indexOf(step) + 1;
  const end = () => write("done");
  const advance = () => {
    if (step === "folder") return write("create");
    if (step === "session") return write("finish");
    end();
  };
  const lost = !rect && step !== "finish";

  // Beside a narrow target (a field in a dialog: below it, the card would
  // cover the rest of the dialog), else under it when there is room, else
  // above; centred when there is no target (the finish, or the page moved).
  const W = 320;
  let style: React.CSSProperties = { left: "50%", top: "50%", transform: "translate(-50%, -50%)" };
  if (rect) {
    const right = (box ?? rect).right;
    const top = Math.min(Math.max(12, rect.top), window.innerHeight - 220);
    const left = Math.min(Math.max(12, rect.left), window.innerWidth - W - 12);
    if (rect.width < window.innerWidth / 2 && right + W + 24 < window.innerWidth) {
      style = { left: right + 16, top };
    } else if (rect.bottom + 180 < window.innerHeight) {
      style = { left, top: rect.bottom + 12 };
    } else {
      style = { left, top: Math.max(12, rect.top - 12), transform: "translateY(-100%)" };
    }
  }

  return createPortal(
    <div className="pointer-events-none fixed inset-0 z-[70]" data-testid="onboarding-tour">
      {rect ? (
        <div
          aria-hidden
          className="absolute rounded-lg ring-2 ring-accent transition-all duration-200"
          style={{
            left: rect.left - 6,
            top: rect.top - 6,
            width: rect.width + 12,
            height: rect.height + 12,
            boxShadow: "0 0 0 9999px rgba(0, 0, 0, 0.55)",
          }}
        />
      ) : (
        step === "finish" && <div aria-hidden className="absolute inset-0 bg-black/55" />
      )}
      <div
        role="dialog"
        aria-live="polite"
        aria-label={t(`tour.${step}.title`)}
        className="pointer-events-auto absolute w-80 space-y-2 rounded-xl border border-border bg-surface-1 p-4 shadow-2xl shadow-black/50"
        style={style}
      >
        <p className="text-[11px] font-semibold uppercase tracking-[0.14em] text-fg-muted">
          {t("tour.progress", { n, total: ORDER.length })}
        </p>
        <p className="text-sm font-semibold text-fg-primary">{t(`tour.${step}.title`)}</p>
        <p className="text-xs leading-relaxed text-fg-secondary">{t(`tour.${step}.body`)}</p>
        <div className="flex items-center gap-2 pt-1">
          {step !== "finish" && (
            <button type="button" onClick={end} className="btn-ghost px-0 text-xs">
              {t("tour.skip")}
            </button>
          )}
          <span className="flex-1" />
          {lost && !location.pathname.startsWith("/workspace") && (
            <button
              type="button"
              onClick={() => navigate("/workspace")}
              className="btn-ghost border border-border text-xs"
            >
              {t("tour.goWorkspaces")}
            </button>
          )}
          {STEPS[step].info && (
            <button
              type="button"
              onClick={advance}
              data-testid="onboarding-tour-next"
              className="btn-primary text-xs"
            >
              {step === "finish" ? t("tour.done") : t("tour.next")}
            </button>
          )}
        </div>
      </div>
    </div>,
    document.body
  );
}