/**
 * Main Navigation Sidebar
 * Displays navigation links for the main application (projects, agents, etc.)
 * Collapsible on mobile with responsive behavior
 */

'use client';

import { useState, useCallback, useEffect } from 'react';
import { Link } from '@/lib/i18n/routing';
import { usePathname } from '@/lib/i18n/routing';
import { cn } from '@/lib/utils';
import { Button } from '@/components/ui/button';
import {
  Sheet,
  SheetContent,
  SheetHeader,
  SheetTitle,
  SheetTrigger,
} from '@/components/ui/sheet';
import {
  FolderKanban,
  Bot,
  LayoutDashboard,
  ListTodo,
  IterationCw,
  Settings,
  ChevronLeft,
  ChevronRight,
  Menu,
  Shield,
} from 'lucide-react';
import { useAuth } from '@/lib/auth/AuthContext';

interface NavItem {
  name: string;
  href: string;
  icon: React.ComponentType<{ className?: string }>;
  /** If true, only matches exact path */
  exact?: boolean;
  /** If true, only visible to superusers */
  adminOnly?: boolean;
}

const mainNavItems: NavItem[] = [
  {
    name: 'Projects',
    href: '/projects',
    icon: FolderKanban,
    exact: true,
  },
];

const projectNavItems: NavItem[] = [
  {
    name: 'Dashboard',
    href: '/dashboard',
    icon: LayoutDashboard,
    exact: true,
  },
  {
    name: 'Issues',
    href: '/issues',
    icon: ListTodo,
  },
  {
    name: 'Sprints',
    href: '/sprints',
    icon: IterationCw,
  },
  {
    name: 'Agents',
    href: '/agents',
    icon: Bot,
  },
  {
    name: 'Settings',
    href: '/settings',
    icon: Settings,
  },
];

const adminNavItems: NavItem[] = [
  {
    name: 'Agent Types',
    href: '/admin/agent-types',
    icon: Bot,
    adminOnly: true,
  },
  {
    name: 'Admin Panel',
    href: '/admin',
    icon: Shield,
    adminOnly: true,
    exact: true,
  },
];

interface SidebarProps {
  /** Current project slug, if viewing a project */
  projectSlug?: string;
  /** Additional className */
  className?: string;
}

interface NavLinkProps {
  item: NavItem;
  collapsed: boolean;
  basePath?: string;
}

function NavLink({ item, collapsed, basePath = '' }: NavLinkProps) {
  const pathname = usePathname();
  const href = basePath ? `${basePath}${item.href}` : item.href;

  const isActive = item.exact
    ? pathname === href
    : pathname.startsWith(href);

  const Icon = item.icon;

  return (
    <Link
      href={href}
      className={cn(
        'flex items-center gap-3 rounded-md px-3 py-2 text-sm font-medium transition-colors',
        'hover:bg-accent hover:text-accent-foreground',
        'focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2',
        isActive ? 'bg-accent text-accent-foreground' : 'text-muted-foreground',
        collapsed && 'justify-center'
      )}
      title={collapsed ? item.name : undefined}
      data-testid={`nav-${item.name.toLowerCase().replace(/\s+/g, '-')}`}
      aria-current={isActive ? 'page' : undefined}
    >
      <Icon className="h-5 w-5 flex-shrink-0" aria-hidden="true" />
      {!collapsed && <span>{item.name}</span>}
    </Link>
  );
}

function SidebarContent({
  collapsed,
  projectSlug,
  onToggle,
}: {
  collapsed: boolean;
  projectSlug?: string;
  onToggle: () => void;
}) {
  const { user } = useAuth();
  const isAdmin = user?.is_superuser ?? false;

  return (
    <div className="flex h-full flex-col">
      {/* Sidebar Header */}
      <div className="flex h-14 items-center justify-between border-b px-4">
        {!collapsed && (
          <span className="text-lg font-semibold text-foreground">Navigation</span>
        )}
        <Button
          variant="ghost"
          size="icon"
          onClick={onToggle}
          className="h-8 w-8"
          aria-label={collapsed ? 'Expand sidebar' : 'Collapse sidebar'}
          data-testid="sidebar-toggle"
        >
          {collapsed ? (
            <ChevronRight className="h-4 w-4" aria-hidden="true" />
          ) : (
            <ChevronLeft className="h-4 w-4" aria-hidden="true" />
          )}
        </Button>
      </div>

      {/* Navigation Links */}
      <nav className="flex-1 space-y-1 overflow-y-auto p-2" aria-label="Main navigation">
        {/* Main navigation */}
        <div className="space-y-1">
          {!collapsed && (
            <span className="px-3 py-2 text-xs font-semibold uppercase tracking-wider text-muted-foreground">
              Main
            </span>
          )}
          {mainNavItems.map((item) => (
            <NavLink key={item.href} item={item} collapsed={collapsed} />
          ))}
        </div>

        {/* Project-specific navigation */}
        {projectSlug && (
          <div className="space-y-1 pt-4">
            {!collapsed && (
              <span className="px-3 py-2 text-xs font-semibold uppercase tracking-wider text-muted-foreground">
                Project
              </span>
            )}
            {projectNavItems.map((item) => (
              <NavLink
                key={item.href}
                item={item}
                collapsed={collapsed}
                basePath={`/projects/${projectSlug}`}
              />
            ))}
          </div>
        )}

        {/* Admin navigation */}
        {isAdmin && (
          <div className="space-y-1 pt-4">
            {!collapsed && (
              <span className="px-3 py-2 text-xs font-semibold uppercase tracking-wider text-muted-foreground">
                Admin
              </span>
            )}
            {adminNavItems
              .filter((item) => !item.adminOnly || isAdmin)
              .map((item) => (
                <NavLink key={item.href} item={item} collapsed={collapsed} />
              ))}
          </div>
        )}
      </nav>

      {/* User Info (only when expanded) */}
      {!collapsed && user && (
        <div className="border-t p-4">
          <div className="flex items-center gap-3">
            <div className="flex h-8 w-8 items-center justify-center rounded-full bg-primary text-primary-foreground text-sm font-medium">
              {user.first_name?.[0]?.toUpperCase() || user.email[0].toUpperCase()}
            </div>
            <div className="flex-1 overflow-hidden">
              <p className="text-sm font-medium truncate">
                {user.first_name} {user.last_name}
              </p>
              <p className="text-xs text-muted-foreground truncate">{user.email}</p>
            </div>
          </div>
        </div>
      )}
    </div>
  );
}

export function Sidebar({ projectSlug, className }: SidebarProps) {
  const [collapsed, setCollapsed] = useState(false);
  const [mobileOpen, setMobileOpen] = useState(false);

  const handleToggle = useCallback(() => {
    setCollapsed((prev) => !prev);
  }, []);

  // Close mobile sidebar on route change
  const pathname = usePathname();
  useEffect(() => {
    setMobileOpen(false);
  }, [pathname]);

  // Handle keyboard shortcut for sidebar toggle (Cmd/Ctrl + B)
  useEffect(() => {
    function handleKeyDown(event: KeyboardEvent) {
      if ((event.metaKey || event.ctrlKey) && event.key === 'b') {
        event.preventDefault();
        setCollapsed((prev) => !prev);
      }
    }

    window.addEventListener('keydown', handleKeyDown);
    return () => window.removeEventListener('keydown', handleKeyDown);
  }, []);

  return (
    <>
      {/* Mobile sidebar trigger */}
      <Sheet open={mobileOpen} onOpenChange={setMobileOpen}>
        <SheetTrigger asChild>
          <Button
            variant="ghost"
            size="icon"
            className="lg:hidden fixed left-4 top-4 z-40"
            aria-label="Open navigation menu"
            data-testid="mobile-menu-trigger"
          >
            <Menu className="h-5 w-5" aria-hidden="true" />
          </Button>
        </SheetTrigger>
        <SheetContent side="left" className="w-64 p-0">
          <SheetHeader className="sr-only">
            <SheetTitle>Navigation Menu</SheetTitle>
          </SheetHeader>
          <SidebarContent
            collapsed={false}
            projectSlug={projectSlug}
            onToggle={() => setMobileOpen(false)}
          />
        </SheetContent>
      </Sheet>

      {/* Desktop sidebar */}
      <aside
        className={cn(
          'hidden lg:flex flex-col border-r bg-muted/40 transition-all duration-300',
          collapsed ? 'w-16' : 'w-64',
          className
        )}
        data-testid="sidebar"
        aria-label="Main navigation"
      >
        <SidebarContent
          collapsed={collapsed}
          projectSlug={projectSlug}
          onToggle={handleToggle}
        />
      </aside>
    </>
  );
}