import { useNavigate, useLocation } from "react-router-dom";
import { useEffect, useRef, useState } from "react";
import { useTranslation } from "react-i18next";
import { api, ApiError } from "../api/client";
import { useAuth } from "../context/AuthContext";
import { useDemoGuide } from "../context/DemoGuideContext";
import { useDemoManifest } from "../context/DemoManifestContext";
import { useViewportTier } from "../hooks/useViewportTier";
import { DEMO_GUIDE_STEPS } from "../data/demoGuideSteps";
import { Icon } from "./Icons";

export function DemoGuideTrigger() {
  const { t } = useTranslation("demo");
  const { user } = useAuth();
  const { open, toggleGuide, currentIndex, completed, totalSteps } = useDemoGuide();

  if (user?.role !== "operations_manager") return null;

  return (
    <button
      type="button"
      className="demo-guide-trigger"
      aria-expanded={open}
      aria-haspopup="dialog"
      onClick={toggleGuide}
    >
      <Icon name="spark" />
      <span>{t("guide.trigger")}</span>
      <span className="demo-guide-progress-pill">{completed.size}/{totalSteps}</span>
      <span className="visually-hidden">, {t("guide.kicker", { current: currentIndex + 1, total: totalSteps })}</span>
    </button>
  );
}

function highlightTarget(selector: string | undefined) {
  if (!selector) return;
  const el = document.querySelector<HTMLElement>(selector);
  if (!el) return;
  el.scrollIntoView({ behavior: "smooth", block: "center" });
  const previousTabIndex = el.getAttribute("tabindex");
  if (!el.hasAttribute("tabindex")) el.setAttribute("tabindex", "-1");
  el.focus({ preventScroll: true });
  el.classList.add("demo-guide-highlight");
  window.setTimeout(() => {
    el.classList.remove("demo-guide-highlight");
    if (previousTabIndex === null) el.removeAttribute("tabindex");
  }, 2200);
}

export function DemoGuide() {
  const { t } = useTranslation("demo");
  const navigate = useNavigate();
  const location = useLocation();
  const { logout } = useAuth();
  const { manifest, refresh } = useDemoManifest();
  const tier = useViewportTier();
  const {
    open,
    closeGuide,
    currentIndex,
    completed,
    totalSteps,
    goToStep,
    completeAndAdvance,
    restart,
    collapsedToChip,
    setCollapsedToChip,
  } = useDemoGuide();
  const [resetting, setResetting] = useState(false);
  const [resetError, setResetError] = useState<string | null>(null);
  const [mobileSheetState, setMobileSheetState] = useState<"collapsed" | "half" | "full">("half");
  const pendingTarget = useRef<string | null>(null);

  const step = DEMO_GUIDE_STEPS[currentIndex];
  const isLastStep = currentIndex === totalSteps - 1;

  useEffect(() => {
    if (!open) return;
    function handleKeydown(event: KeyboardEvent) {
      if (event.key !== "Escape") return;
      if (tier === "standard" && !collapsedToChip) {
        setCollapsedToChip(true);
      } else if (tier === "mobile" && mobileSheetState !== "collapsed") {
        setMobileSheetState("collapsed");
      } else {
        closeGuide();
      }
    }
    document.addEventListener("keydown", handleKeydown);
    return () => document.removeEventListener("keydown", handleKeydown);
  }, [open, tier, collapsedToChip, mobileSheetState, closeGuide]);

  useEffect(() => {
    if (!pendingTarget.current) return;
    const target = pendingTarget.current;
    pendingTarget.current = null;
    const raf = requestAnimationFrame(() => highlightTarget(target));
    return () => cancelAnimationFrame(raf);
  }, [location.pathname]);

  if (!open) return null;

  function goToStepRoute() {
    pendingTarget.current = step.target ?? null;
    navigate(step.route(manifest));
    if (tier === "standard") setCollapsedToChip(true);
    if (tier === "mobile") setMobileSheetState("collapsed");
  }

  async function handleRestartDemo() {
    setResetError(null);
    setResetting(true);
    try {
      await api.post("/api/v1/demo/reset");
      restart();
      refresh();
      closeGuide();
      await logout();
      navigate("/login");
    } catch (err) {
      setResetError(err instanceof ApiError ? err.message : t("guide.restartFailed"));
    } finally {
      setResetting(false);
    }
  }

  if (tier === "standard" && collapsedToChip) {
    return (
      <div className="demo-guide-chip">
        <button
          type="button"
          className="demo-guide-chip-expand"
          onClick={() => setCollapsedToChip(false)}
          aria-label={`${t("guide.progressChip", { current: currentIndex + 1, total: totalSteps })}, ${t("guide.expand")}`}
        >
          <Icon name="spark" />
          {t("guide.progressChip", { current: currentIndex + 1, total: totalSteps })}
          <Icon name="chevron" />
        </button>
        <button type="button" className="demo-guide-chip-close" onClick={closeGuide} aria-label={t("guide.close")}>
          <Icon name="x" />
        </button>
      </div>
    );
  }

  const panelClassName = [
    "demo-guide-panel",
    tier === "wide" ? "is-wide" : "",
    tier === "mobile" ? `is-mobile sheet-${mobileSheetState}` : "",
  ]
    .filter(Boolean)
    .join(" ");

  return (
    <aside className={panelClassName} role="dialog" aria-label={t("guide.dialogLabel")}>
      {tier === "mobile" && (
        <button
          type="button"
          className="demo-guide-sheet-handle"
          onClick={() =>
            setMobileSheetState((s) => (s === "collapsed" ? "half" : s === "half" ? "full" : "collapsed"))
          }
          aria-label={
            mobileSheetState === "full"
              ? t("guide.collapse")
              : t("guide.expand")
          }
        >
          <span aria-hidden="true" />
        </button>
      )}

      <header className="demo-guide-header">
        <div>
          <p className="demo-guide-kicker">{t("guide.kicker", { current: currentIndex + 1, total: totalSteps })}</p>
          <h2>{t(`guide.steps.${step.id}.title`)}</h2>
        </div>
        {tier !== "mobile" && (
          <button
            type="button"
            className="icon-button"
            onClick={tier === "standard" ? () => setCollapsedToChip(true) : closeGuide}
            aria-label={tier === "standard" ? t("guide.collapse") : t("guide.close")}
          >
            <Icon name="x" />
          </button>
        )}
      </header>

      {mobileSheetState !== "collapsed" && (
        <>
          <div className="demo-guide-progress-bar" aria-hidden="true">
            {DEMO_GUIDE_STEPS.map((s, index) => (
              <span
                key={s.id}
                className={
                  index === currentIndex ? "is-current" : completed.has(s.id) ? "is-done" : ""
                }
              />
            ))}
          </div>

          {(mobileSheetState !== "half" || tier !== "mobile") && (
            <div className="demo-guide-body">
              <p><strong>{t("guide.whatYouWillSee")}</strong><br />{t(`guide.steps.${step.id}.whatYouWillSee`)}</p>
              <p><strong>{t("guide.whyItMatters")}</strong><br />{t(`guide.steps.${step.id}.whyItMatters`)}</p>
              <p><strong>{t("guide.startAction")}</strong><br />{t(`guide.steps.${step.id}.startAction`)}</p>
              <p><strong>{t("guide.expectedOutcome")}</strong><br />{t(`guide.steps.${step.id}.expectedOutcome`)}</p>
            </div>
          )}

          {tier !== "mobile" && (
            <nav className="demo-guide-steps" aria-label={t("guide.allStepsLabel")}>
              {DEMO_GUIDE_STEPS.map((s, index) => (
                <button
                  key={s.id}
                  type="button"
                  className={index === currentIndex ? "is-current" : ""}
                  onClick={() => goToStep(index)}
                >
                  {completed.has(s.id) && <Icon name="check" />}
                  {t(`guide.steps.${s.id}.title`)}
                </button>
              ))}
            </nav>
          )}

          {resetError && <p className="error" role="alert">{resetError}</p>}

          <footer className="demo-guide-footer">
            <button type="button" className="button button-secondary" onClick={goToStepRoute}>
              {t("guide.goToStep")}
            </button>
            <button type="button" className="button button-primary" onClick={completeAndAdvance} disabled={isLastStep}>
              {t("guide.next")}
            </button>
            {tier !== "mobile" && (
              <button type="button" className="demo-guide-restart" onClick={handleRestartDemo} disabled={resetting}>
                {resetting ? t("guide.restarting") : t("guide.restart")}
              </button>
            )}
          </footer>
        </>
      )}
    </aside>
  );
}