// components/NavBar.tsx
// Top-of-page navigation. Logo lockup on the left, primary nav
// center, secondary status on the right. Sticky on scroll with the
// signature hairline border-bottom.
//
// Mobile (<md): no tab bar. The header carries a hamburger that opens
// a full-screen menu panel listing every section, grouped. A previous
// iteration tried a fixed bottom tab bar, but all 15 routes were
// crammed into a 390px phone width (≈17px per tab, labels cut to one
// letter) — unusable. The full-screen menu keeps every section one
// tap away with full-size rows.
//
// Desktop (md+): primary links inline, everything else behind a
// "More" dropdown. The full 15-link row needed 1752px inside a
// 1280px container, which pushed the right-hand cluster off-screen
// and gave the whole page a horizontal scrollbar.
//
// Icons use stroke-currentColor at 1.6px per the design system
// (anti-slop rule: emoji and gradient icons are forbidden). Brand
// mark "Y" pill in the top-left stays on all viewports.

"use client";

import Link from "next/link";
import { usePathname } from "next/navigation";
import { useTheme } from "next-themes";
import { useEffect, useRef, useState } from "react";
import type { ReactNode } from "react";

const LINKS = [
  { href: "/", label: "Overview", icon: IconHome },
  { href: "/notes", label: "Notes", icon: IconNotepad },
  { href: "/bizportal", label: "BizPortal", icon: IconSearch },
  { href: "/bizportal-2", label: "BizPortal 2.0", icon: IconSearch, badge: "test" },
  { href: "/cipc", label: "CIPC", icon: IconSearch },
  { href: "/cipc-2", label: "CIPC2.0", icon: IconSearch, badge: "test" },
  { href: "/cipc-report", label: "CIPC Report", icon: IconCheckSquare },
  { href: "/sars-returns", label: "SARS Returns", icon: IconReceipt },
  { href: "/sars-registrations", label: "SARS Registrations", icon: IconRegistry },
  { href: "/tasks", label: "Tasks", icon: IconClipboard },
  { href: "/directors", label: "Directors", icon: IconUsers },
  { href: "/companies", label: "Companies", icon: IconBuilding },
  { href: "/groups", label: "Groups", icon: IconTag },
  { href: "/compliance", label: "Compliance", icon: IconCheckSquare },
  { href: "/resolutions", label: "Resolutions", icon: IconDocument },
] as const;

type LinkItem = (typeof LINKS)[number];

const LINK_BY_HREF: Record<string, LinkItem> = Object.fromEntries(
  LINKS.map((l) => [l.href, l]),
) as Record<string, LinkItem>;

/** Sections that stay one click away in the desktop header. */
const DESKTOP_PRIMARY = [
  "/",
  "/notes",
  "/companies",
  "/directors",
  "/tasks",
  "/compliance",
] as const;

/** Every section, grouped — the shared source of truth for the mobile
 *  menu panel and the desktop "More" dropdown. */
const MENU_GROUPS: { title: string; hrefs: string[] }[] = [
  { title: "Main", hrefs: ["/", "/tasks", "/directors", "/companies"] },
  {
    title: "CIPC & BizPortal",
    hrefs: ["/bizportal", "/bizportal-2", "/cipc", "/cipc-2", "/cipc-report"],
  },
  { title: "SARS", hrefs: ["/sars-returns", "/sars-registrations"] },
  { title: "Practice", hrefs: ["/notes", "/groups", "/compliance", "/resolutions"] },
];

export default function NavBar() {
  const pathname = usePathname() ?? "/";
  const [menuOpen, setMenuOpen] = useState(false);
  const [moreOpen, setMoreOpen] = useState(false);
  const moreRef = useRef<HTMLDivElement | null>(null);
  const closeRef = useRef<HTMLButtonElement | null>(null);

  // Navigating away closes whichever surface was open.
  useEffect(() => {
    setMenuOpen(false);
    setMoreOpen(false);
  }, [pathname]);

  // The mobile panel is a modal surface: lock the page behind it.
  useEffect(() => {
    if (!menuOpen) return;
    const previous = document.body.style.overflow;
    document.body.style.overflow = "hidden";
    closeRef.current?.focus();
    const onKey = (e: KeyboardEvent) => {
      if (e.key === "Escape") setMenuOpen(false);
    };
    document.addEventListener("keydown", onKey);
    return () => {
      document.body.style.overflow = previous;
      document.removeEventListener("keydown", onKey);
    };
  }, [menuOpen]);

  // The desktop dropdown closes on an outside click or Escape.
  useEffect(() => {
    if (!moreOpen) return;
    const onKey = (e: KeyboardEvent) => {
      if (e.key === "Escape") setMoreOpen(false);
    };
    const onPointer = (e: MouseEvent) => {
      if (!moreRef.current?.contains(e.target as Node)) setMoreOpen(false);
    };
    document.addEventListener("keydown", onKey);
    document.addEventListener("mousedown", onPointer);
    return () => {
      document.removeEventListener("keydown", onKey);
      document.removeEventListener("mousedown", onPointer);
    };
  }, [moreOpen]);

  const primaryLinks = LINKS.filter((l) =>
    (DESKTOP_PRIMARY as readonly string[]).includes(l.href),
  );

  return (
    <>
      <header
        data-od-id="navbar"
        className="sticky top-0 z-30 bg-surface border-b border-border"
      >
        <div className="container-x flex items-center justify-between h-[calc(5rem+env(safe-area-inset-top))] pt-[env(safe-area-inset-top)]">
          <Link
            href="/"
            data-od-id="brand-mark"
            className="flex items-center gap-2 no-underline"
          >
            <span
              aria-hidden="true"
              className="inline-flex items-center justify-center w-8 h-8 rounded-pill bg-accent text-accent-on font-bold text-sm"
            >
              Y
            </span>
            <span className="text-lg font-bold text-fg tracking-tight">
              Workflow
            </span>
          </Link>

          <nav
            className="hidden md:flex items-center gap-2"
            aria-label="Primary"
          >
            {primaryLinks.map((link) => {
              const isActive = isActiveLink(pathname, link.href);
              return (
                <Link
                  key={link.href}
                  href={link.href}
                  data-od-id={`nav-${link.label.toLowerCase().replace(/\s+/g, "-")}`}
                  className={
                    "px-4 py-2 rounded-md text-sm font-semibold no-underline transition-colors inline-flex items-center gap-2 " +
                    (isActive
                      ? "bg-surface-warm text-fg"
                      : "text-fg hover:bg-surface-warm")
                  }
                >
                  <span>{link.label}</span>
                </Link>
              );
            })}

            {/* Overflow dropdown — the desktop counterpart of the
                mobile menu panel. */}
            <div className="relative" ref={moreRef}>
              <button
                type="button"
                onClick={() => setMoreOpen((v) => !v)}
                aria-expanded={moreOpen}
                aria-haspopup="true"
                aria-label="More sections"
                data-od-id="desktop-more-button"
                className={
                  "px-4 py-2 rounded-md text-sm font-semibold transition-colors inline-flex items-center gap-1.5 " +
                  (moreOpen || isOverflowActive(pathname)
                    ? "bg-surface-warm text-fg"
                    : "text-fg hover:bg-surface-warm")
                }
              >
                More
                <svg
                  viewBox="0 0 24 24"
                  fill="none"
                  stroke="currentColor"
                  strokeWidth="1.8"
                  strokeLinecap="round"
                  strokeLinejoin="round"
                  className={
                    "w-4 h-4 transition-transform " + (moreOpen ? "rotate-180" : "")
                  }
                  aria-hidden="true"
                >
                  <polyline points="6,9 12,15 18,9" />
                </svg>
              </button>

              {moreOpen ? (
                <div
                  data-od-id="desktop-more-panel"
                  className="absolute right-0 top-full mt-2 w-[340px] max-h-[70vh] overflow-y-auto bg-surface border border-border rounded-lg shadow-raised p-2 z-40"
                >
                  <GroupedList onNavigate={() => setMoreOpen(false)} />
                </div>
              ) : null}
            </div>
          </nav>

          {/* Right-side desktop cluster: label + theme toggle. Hidden
              on mobile — the menu panel carries both. */}
          <div className="hidden md:flex items-center gap-3">
            <span className="hidden lg:inline text-xs text-muted">
              Registry Browser
            </span>
            <ThemeToggle />
          </div>

          {/* Mobile: hamburger opens the full-screen menu. */}
          <button
            type="button"
            onClick={() => setMenuOpen(true)}
            aria-label="Open menu"
            aria-haspopup="dialog"
            aria-expanded={menuOpen}
            data-od-id="mobile-menu-button"
            className="md:hidden inline-flex items-center justify-center w-10 h-10 -mr-2 rounded-md text-fg"
          >
            <IconMenu className="w-6 h-6" />
          </button>
        </div>
      </header>

      {/* Mobile full-screen menu panel. */}
      {menuOpen ? (
        <div
          role="dialog"
          aria-modal="true"
          aria-label="Main menu"
          data-od-id="mobile-menu-panel"
          className="md:hidden fixed inset-0 z-50 bg-bg overflow-y-auto"
        >
          <div className="sticky top-0 bg-surface border-b border-border">
            <div className="container-x flex items-center justify-between h-[calc(5rem+env(safe-area-inset-top))] pt-[env(safe-area-inset-top)]">
              <Link href="/" className="flex items-center gap-2 no-underline">
                <span
                  aria-hidden="true"
                  className="inline-flex items-center justify-center w-8 h-8 rounded-pill bg-accent text-accent-on font-bold text-sm"
                >
                  Y
                </span>
                <span className="text-lg font-bold text-fg tracking-tight">
                  Workflow
                </span>
              </Link>
              <button
                ref={closeRef}
                type="button"
                onClick={() => setMenuOpen(false)}
                aria-label="Close menu"
                data-od-id="mobile-menu-close"
                className="w-10 h-10 -mr-2 inline-flex items-center justify-center rounded-md text-fg"
              >
                <IconClose className="w-6 h-6" />
              </button>
            </div>
          </div>

          <GroupedList onNavigate={() => setMenuOpen(false)} />

          <div className="container-x flex items-center justify-between py-6 pb-[calc(env(safe-area-inset-bottom)+24px)]">
            <span className="text-xs text-muted">Registry Browser</span>
            <ThemeToggle />
          </div>
        </div>
      ) : null}
    </>
  );
}

/**
 * Grouped list of every section, shared by the mobile menu panel and
 * the desktop "More" dropdown.
 */
function GroupedList({ onNavigate }: { onNavigate?: () => void }) {
  const pathname = usePathname() ?? "/";
  return (
    <div className="px-4 pb-2 md:px-0">
      {MENU_GROUPS.map((group) => (
        <div key={group.title} className="pt-5">
          <p className="text-[11px] font-bold uppercase tracking-wider text-meta mb-1 px-1">
            {group.title}
          </p>
          <ul>
            {group.hrefs.map((href) => {
              const link = LINK_BY_HREF[href];
              if (!link) return null;
              const Icon = link.icon;
              const active = isActiveLink(pathname, href);
              return (
                <li key={href}>
                  <Link
                    href={href}
                    onClick={onNavigate}
                    className="flex items-center gap-3 py-2.5 no-underline rounded-md px-1"
                  >
                    <span
                      className={
                        "w-9 h-9 rounded-md inline-flex items-center justify-center shrink-0 " +
                        (active
                          ? "bg-accent text-accent-on"
                          : "bg-surface-warm text-muted")
                      }
                    >
                      <Icon className="w-5 h-5" active={active} />
                    </span>
                    <span
                      className={
                        "text-[15px] font-semibold " +
                        (active ? "text-accent" : "text-fg")
                      }
                    >
                      {link.label}
                    </span>
                    {"badge" in link && link.badge ? (
                      <span className="text-[10px] font-bold uppercase tracking-wider px-1.5 py-0.5 rounded bg-amber-100 text-amber-800 border border-amber-300">
                        {link.badge}
                      </span>
                    ) : null}
                    <IconChevronRight className="w-4 h-4 ml-auto text-meta shrink-0" />
                  </Link>
                </li>
              );
            })}
          </ul>
        </div>
      ))}
    </div>
  );
}

function isActiveLink(pathname: string, href: string): boolean {
  if (href === "/") return pathname === "/";
  return pathname === href || pathname.startsWith(href + "/");
}

/** True when the current route lives behind the "More" dropdown. */
function isOverflowActive(pathname: string): boolean {
  return LINKS.some(
    (l) =>
      !(DESKTOP_PRIMARY as readonly string[]).includes(l.href) &&
      isActiveLink(pathname, l.href),
  );
}

/* ─── Icon set (inline SVG, stroke-currentColor, 1.6px stroke) ──── */

interface IconProps {
  className?: string;
  /** Active state hints — used to swap fill behavior on the home icon
   *  and to thicken the stroke on outlined icons. Always defaults to
   *  the brand "muted" rendering since the active state is owned by
   *  the parent (text color + scale already encodes it). */
  active?: boolean;
}

function IconHome({ className, active }: IconProps): ReactNode {
  return (
    <svg
      viewBox="0 0 24 24"
      fill={active ? "currentColor" : "none"}
      stroke="currentColor"
      strokeWidth={1.6}
      strokeLinecap="round"
      strokeLinejoin="round"
      className={className}
      aria-hidden="true"
    >
      <path d="M3 11.5L12 4l9 7.5" />
      <path d="M5 10.5V20a1 1 0 0 0 1 1h4v-6h4v6h4a1 1 0 0 0 1-1v-9.5" />
    </svg>
  );
}

function IconUsers({ className }: IconProps): ReactNode {
  return (
    <svg
      viewBox="0 0 24 24"
      fill="none"
      stroke="currentColor"
      strokeWidth="1.6"
      strokeLinecap="round"
      strokeLinejoin="round"
      className={className}
      aria-hidden="true"
    >
      <circle cx="9" cy="9" r="3.2" />
      <path d="M3.5 19c.7-3 3-4.6 5.5-4.6S13.8 16 14.5 19" />
      <circle cx="16.5" cy="9" r="2.6" />
      <path d="M15.2 14.4c2 0 4 1.4 4.6 4" />
    </svg>
  );
}

function IconBuilding({ className }: IconProps): ReactNode {
  return (
    <svg
      viewBox="0 0 24 24"
      fill="none"
      stroke="currentColor"
      strokeWidth="1.6"
      strokeLinecap="round"
      strokeLinejoin="round"
      className={className}
      aria-hidden="true"
    >
      <rect x="4" y="3" width="16" height="18" rx="1.5" />
      <path d="M8 7h2M8 11h2M8 15h2M14 7h2M14 11h2M14 15h2" />
      <path d="M10 21v-3h4v3" />
    </svg>
  );
}

function IconDocument({ className }: IconProps): ReactNode {
  return (
    <svg
      viewBox="0 0 24 24"
      fill="none"
      stroke="currentColor"
      strokeWidth="1.6"
      strokeLinecap="round"
      strokeLinejoin="round"
      className={className}
      aria-hidden="true"
    >
      <path d="M14 2H6a2 2 0 0 0-2 2v16a2 2 0 0 0 2 2h12a2 2 0 0 0 2-2V8z" />
      <polyline points="14,2 14,8 20,8" />
      <line x1="9" y1="13" x2="15" y2="13" />
      <line x1="9" y1="17" x2="13" y2="17" />
    </svg>
  );
}

function IconClipboard({ className }: IconProps): ReactNode {
  return (
    <svg
      viewBox="0 0 24 24"
      fill="none"
      stroke="currentColor"
      strokeWidth="1.6"
      strokeLinecap="round"
      strokeLinejoin="round"
      className={className}
      aria-hidden="true"
    >
      <rect x="8" y="2" width="8" height="4" rx="1" />
      <path d="M16 4h2a2 2 0 0 1 2 2v14a2 2 0 0 1-2 2H6a2 2 0 0 1-2-2V6a2 2 0 0 1 2-2h2" />
      <line x1="9" y1="13" x2="15" y2="13" />
      <line x1="9" y1="17" x2="12" y2="17" />
    </svg>
  );
}

function IconSearch({ className }: IconProps): ReactNode {
  return (
    <svg
      viewBox="0 0 24 24"
      fill="none"
      stroke="currentColor"
      strokeWidth="1.6"
      strokeLinecap="round"
      strokeLinejoin="round"
      className={className}
      aria-hidden="true"
    >
      <circle cx="11" cy="11" r="7" />
      <line x1="21" y1="21" x2="16.65" y2="16.65" />
    </svg>
  );
}

function IconTag({ className }: IconProps): ReactNode {
  return (
    <svg
      viewBox="0 0 24 24"
      fill="none"
      stroke="currentColor"
      strokeWidth="1.6"
      strokeLinecap="round"
      strokeLinejoin="round"
      className={className}
      aria-hidden="true"
    >
      <path d="M20.59 13.41l-7.17 7.17a2 2 0 0 1-2.83 0L2 12V2h10l8.59 8.59a2 2 0 0 1 0 2.82z" />
      <line x1="7" y1="7" x2="7.01" y2="7" />
    </svg>
  );
}

function IconCheckSquare({ className }: IconProps): ReactNode {
  return (
    <svg
      viewBox="0 0 24 24"
      fill="none"
      stroke="currentColor"
      strokeWidth="1.6"
      strokeLinecap="round"
      strokeLinejoin="round"
      className={className}
      aria-hidden="true"
    >
      <rect x="3" y="3" width="18" height="18" rx="2" />
      <path d="M9 12l2 2 4-4" />
    </svg>
  );
}

/**
 * Tax-receipt glyph for the SARS Returns tab. Deliberately a torn-
 * edge receipt (zig-zag bottom) to distinguish it from IconDocument
 * (which is a sealed page) and IconClipboard (which has a clip).
 */
function IconReceipt({ className }: IconProps): ReactNode {
  return (
    <svg
      viewBox="0 0 24 24"
      fill="none"
      stroke="currentColor"
      strokeWidth="1.6"
      strokeLinecap="round"
      strokeLinejoin="round"
      className={className}
      aria-hidden="true"
    >
      <path d="M5 3h14v18l-2-1.6L15 21l-2-1.6L11 21l-2-1.6L7 21l-2-1.6V3z" />
      <line x1="9" y1="8" x2="15" y2="8" />
      <line x1="9" y1="12" x2="15" y2="12" />
      <line x1="9" y1="16" x2="13" y2="16" />
    </svg>
  );
}

/**
 * Registry / ID-badge glyph for the SARS Registrations tab. A card with
 * two horizontal ruled lines and a small "stamp" circle in the corner —
 * visually distinct from IconReceipt (torn-edge paper), IconNotepad
 * (folded top-right page), IconDocument (sealed page), and
 * IconClipboard (task list with a clip).
 */
function IconRegistry({ className }: IconProps): ReactNode {
  return (
    <svg
      viewBox="0 0 24 24"
      fill="none"
      stroke="currentColor"
      strokeWidth="1.6"
      strokeLinecap="round"
      strokeLinejoin="round"
      className={className}
      aria-hidden="true"
    >
      <rect x="3.5" y="4.5" width="14" height="13" rx="1.6" />
      <line x1="6.5" y1="8.5" x2="14.5" y2="8.5" />
      <line x1="6.5" y1="11.5" x2="14.5" y2="11.5" />
      <line x1="6.5" y1="14" x2="11.5" y2="14" />
      <circle cx="17.5" cy="17" r="3" />
      <path d="M16.2 17l1 1 1.6-1.8" />
    </svg>
  );
}

/**
 * Notepad glyph for the Notes tab. Rounded rectangle with a horizontal
 * ruled line and a folded top-right corner — distinguishes it from
 * IconClipboard (task list with a clip) and IconDocument (sealed page).
 */
function IconNotepad({ className }: IconProps): ReactNode {
  return (
    <svg
      viewBox="0 0 24 24"
      fill="none"
      stroke="currentColor"
      strokeWidth="1.6"
      strokeLinecap="round"
      strokeLinejoin="round"
      className={className}
      aria-hidden="true"
    >
      <path d="M14 2H6a2 2 0 0 0-2 2v16a2 2 0 0 0 2 2h11a1 1 0 0 0 1-1V8z" />
      <polyline points="14,2 14,8 19,8" />
      <line x1="8" y1="13" x2="16" y2="13" />
      <line x1="8" y1="17" x2="14" y2="17" />
    </svg>
  );
}

/** Hamburger glyph for the mobile menu button. */
function IconMenu({ className }: IconProps): ReactNode {
  return (
    <svg
      viewBox="0 0 24 24"
      fill="none"
      stroke="currentColor"
      strokeWidth="1.8"
      strokeLinecap="round"
      className={className}
      aria-hidden="true"
    >
      <line x1="3.5" y1="7" x2="20.5" y2="7" />
      <line x1="3.5" y1="12" x2="20.5" y2="12" />
      <line x1="3.5" y1="17" x2="20.5" y2="17" />
    </svg>
  );
}

/** Close glyph for the mobile menu panel. */
function IconClose({ className }: IconProps): ReactNode {
  return (
    <svg
      viewBox="0 0 24 24"
      fill="none"
      stroke="currentColor"
      strokeWidth="1.8"
      strokeLinecap="round"
      className={className}
      aria-hidden="true"
    >
      <line x1="5" y1="5" x2="19" y2="19" />
      <line x1="19" y1="5" x2="5" y2="19" />
    </svg>
  );
}

/** Right-chevron used as the list affordance in the grouped lists. */
function IconChevronRight({ className }: IconProps): ReactNode {
  return (
    <svg
      viewBox="0 0 24 24"
      fill="none"
      stroke="currentColor"
      strokeWidth="1.8"
      strokeLinecap="round"
      strokeLinejoin="round"
      className={className}
      aria-hidden="true"
    >
      <polyline points="9.5,5 16.5,12 9.5,19" />
    </svg>
  );
}

/* ─── Theme toggle ────────────────────────────────────────────────── */

/**
 * Sun/moon button. Uses next-themes' `resolvedTheme` so system
 * preference is honoured. The icon shown represents the mode you'd
 * switch TO (moon in light, sun in dark).
 *
 * `mounted` guard avoids SSR/CSR mismatch — `useTheme` returns
 * undefined on the first render. Until mounted, we render a neutral
 * placeholder so the button's box doesn't pop in late.
 */
function ThemeToggle() {
  const [mounted, setMounted] = useState(false);
  const { resolvedTheme, setTheme } = useTheme();
  useEffect(() => setMounted(true), []);

  const isDark = mounted && resolvedTheme === "dark";
  const next = isDark ? "light" : "dark";

  return (
    <button
      type="button"
      onClick={() => setTheme(next)}
      aria-label={mounted ? `Switch to ${next} mode` : "Toggle theme"}
      title={`Switch to ${next} mode`}
      data-od-id="theme-toggle"
      className="inline-flex items-center justify-center w-9 h-9 rounded-md text-fg hover:bg-surface-warm transition-colors"
    >
      {mounted ? (
        isDark ? (
          <IconSun className="w-5 h-5" />
        ) : (
          <IconMoon className="w-5 h-5" />
        )
      ) : (
        // Neutral placeholder slot — same dimensions so layout doesn't shift.
        <span className="w-5 h-5 block" aria-hidden="true" />
      )}
    </button>
  );
}

function IconSun({ className }: IconProps): ReactNode {
  return (
    <svg
      viewBox="0 0 24 24"
      fill="none"
      stroke="currentColor"
      strokeWidth="1.6"
      strokeLinecap="round"
      strokeLinejoin="round"
      className={className}
      aria-hidden="true"
    >
      <circle cx="12" cy="12" r="4" />
      <path d="M12 2v2M12 20v2M4.93 4.93l1.41 1.41M17.66 17.66l1.41 1.41M2 12h2M20 12h2M4.93 19.07l1.41-1.41M17.66 6.34l1.41-1.41" />
    </svg>
  );
}

function IconMoon({ className }: IconProps): ReactNode {
  return (
    <svg
      viewBox="0 0 24 24"
      fill="none"
      stroke="currentColor"
      strokeWidth="1.6"
      strokeLinecap="round"
      strokeLinejoin="round"
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      aria-hidden="true"
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  );
}