"use client";

/**
 * BuilderNav.tsx
 * -----------------------------------------------------------------------------
 * Top navigation for the Builder experience.
 *
 * MAJOR LAYOUT IDEA:
 * - Keep all primary nav items on the LEFT
 * - Put *everything else* (search, viewing state, theme toggle later, user menu later)
 *   into a RIGHT "actions cluster" using a single `ml-auto` wrapper.
 *
 * WHY:
 * - Prevents multiple `ml-auto` elements fighting each other
 * - Makes the right side easy to extend without breaking alignment
 */

import Link from "next/link";
import { useSearchParams } from "next/navigation";
import { CATEGORIES } from "@/data/gunbuilderParts";
import type { Category } from "@/types/builderSlots";

type BuilderNavProps = {
  // Optional override if a parent wants to force the active category
  activeCategoryId?: string | null;
};

/**
 * Helper: group categories for dropdowns.
 * This assumes your Category has a `group` field like "lower" | "upper" | "accessories".
 */
function groupCategories(group: "lower" | "upper" | "accessories"): Category[] {
  return CATEGORIES.filter((c) => c.group === group);
}

export function BuilderNav({ activeCategoryId }: BuilderNavProps) {
  const searchParams = useSearchParams();

  // ---- Data / derived state --------------------------------------------------
  const lower = groupCategories("lower");
  const upper = groupCategories("upper");
  const accessories = groupCategories("accessories");

  // Determine which category is "active" so we can highlight dropdown items
  // and show the "Viewing" indicator on the right.
  const currentCategory =
    activeCategoryId ?? searchParams.get("category") ?? undefined;

  // Base route for parts browsing (used for dropdown links + "Clear")
  const baseHref = "/parts";

  /**
   * Dropdown renderer (hover-based).
   * - Uses Tailwind `group` + `group-hover` to show/hide the menu.
   * - Highlights the active item.
   */
  const renderDropdown = (label: string, items: Category[]) => {
    if (!items.length) return null;

    const platform = searchParams.get("platform");

    return (
      <div className="relative group">
        {/* Dropdown trigger */}
        <button
          type="button"
          className={`inline-flex items-center gap-1 font-medium tracking-wide uppercase text-[11px] transition-colors ${
            items.some((cat) => cat.id === currentCategory)
              ? "text-white"
              : "text-neutral-300 hover:text-white"
          }`}
        >
          {label}
          <span className="text-[9px]">▾</span>
        </button>

        {/* Dropdown menu */}
        <div className="invisible opacity-0 group-hover:visible group-hover:opacity-100 transition-all absolute left-0 mt-2 rounded-md border border-neutral-800 bg-black/95 shadow-xl z-100 min-w-[220px]">
          <ul className="py-2 text-sm">
            {items.map((cat) => {
              const isActive = currentCategory === cat.id;
              return (
                <li key={cat.id}>
                  <Link
                    href={{
                      pathname: `${baseHref}/${cat.id}`,
                      query: platform ? { platform } : {},
                    }}
                    className={`block w-full px-3 py-1.5 transition-colors ${
                      isActive
                        ? "bg-neutral-800 text-white"
                        : "text-neutral-300 hover:bg-neutral-800 hover:text-white"
                    }`}
                  >
                    {cat.name}
                  </Link>
                </li>
              );
            })}
          </ul>
        </div>
      </div>
    );
  };

  return (
    /**
     * Outer container matches TopNav width:
     * - max-w-6xl mx-auto w-full ensures consistent alignment across app
     */
    <div className="max-w-6xl mx-auto w-full">
      {/**
       * FLEX STRATEGY:
       * - Everything before the RIGHT cluster is "left side"
       * - Then a single `ml-auto` cluster pushes everything else to the right
       */}
      <nav className="relative z-50 flex items-center gap-6 border-b border-neutral-900 px-6 py-3 text-sm backdrop-blur-sm">
        {/* ------------------------------------------------------------------ */}
        {/* LEFT SIDE: primary nav */}
        {/* ------------------------------------------------------------------ */}

        <Link
          href="/builder"
          className="font-semibold text-neutral-100 hover:text-white tracking-[0.25em] uppercase text-[11px]"
        >
          Builder
        </Link>

        {renderDropdown("Lower Parts", lower)}
        {renderDropdown("Upper Parts", upper)}
        {renderDropdown("Accessories", accessories)}

        <Link
          href="/builds"
          className="font-medium text-neutral-300 hover:text-white tracking-[0.25em] uppercase text-[11px]"
        >
          Builds
        </Link>

        {/* ------------------------------------------------------------------ */}
        {/* RIGHT SIDE: actions + state */}
        {/* IMPORTANT: this is the ONLY `ml-auto` in the nav to avoid conflicts */}
        {/* ------------------------------------------------------------------ */}
        <div className="ml-auto flex items-center gap-3">
          {/* Search icon (placeholder action) */}
          <button
            type="button"
            className="inline-flex h-8 w-8 items-center justify-center rounded-full border border-zinc-700 bg-zinc-900/60 text-zinc-400 hover:text-zinc-200 hover:bg-zinc-800 hover:border-zinc-500 transition-colors"
            aria-label="Search (coming soon)"
            title="Search (coming soon)"
          >
            <svg
              xmlns="http://www.w3.org/2000/svg"
              viewBox="0 0 24 24"
              fill="none"
              stroke="currentColor"
              strokeWidth={2}
              strokeLinecap="round"
              strokeLinejoin="round"
              className="h-4 w-4"
            >
              <circle cx="11" cy="11" r="6" />
              <line x1="16.5" y1="16.5" x2="21" y2="21" />
            </svg>
          </button>

          {/* "Viewing" indicator (only shows when a category is active) */}
          {currentCategory && (
            <div className="flex items-center gap-2 text-neutral-400 text-xs">
              <span className="uppercase tracking-wide text-[10px]">
                Viewing
              </span>

              <span className="font-medium text-neutral-100">
                {CATEGORIES.find((c) => c.id === currentCategory)?.name ??
                  currentCategory}
              </span>

              {/* Clears category filter -> go back to /parts */}
              <Link
                href={baseHref}
                className="rounded border border-neutral-700 px-2 py-0.5 text-[10px] uppercase tracking-wide hover:bg-neutral-800 hover:text-white"
              >
                Clear
              </Link>
            </div>
          )}

          {/* FUTURE: drop in ThemeToggle, UserMenu, Notifications here */}
          {/* <ThemeToggle /> */}
          {/* <UserMenu /> */}
        </div>
      </nav>
    </div>
  );
}

export default BuilderNav;
