import React, { useEffect, useMemo, useRef, useState } from 'react';
import { Search, Settings } from 'lucide-react';
import { Input } from '../ui/input';
import { Button } from '../ui/button';
import { Avatar, AvatarFallback, AvatarImage } from '../ui/avatar';
import { useAuth } from '../auth/AuthProvider';
import { displayNameFromUser, displayRolesFromCodes } from '../../lib/currentUserDisplay';
import { formatRelativeSince } from '../../lib/relativeSince';
import type { CurrentUserMenuNodeDto } from '../../types/authSession';
import {
  buildGlobalMenuSearchItems,
  filterGlobalMenuSearchItems,
} from '../../lib/globalMenuSearch';
import { cn } from '../ui/utils';

interface HeaderProps {
  title: string;
  menus?: CurrentUserMenuNodeDto[];
  /** 选中搜索结果后跳转（与侧栏 setCurrentView 一致） */
  onNavigate?: (view: string) => void;
  /** 右上角设置：默认跳转 Support，与侧栏一致 */
  onSettingsClick?: () => void;
  /** 点击右上角姓名/角色区域：进入当前用户编辑（由 Layout/App 处理路由） */
  onProfileClick?: () => void;
}

export function Header({ title, menus, onNavigate, onSettingsClick, onProfileClick }: HeaderProps) {
  const auth = useAuth();
  const displayName = displayNameFromUser(auth.user);
  /** 第一行：姓名；第二行：接口返回的人类可读角色（如 Partner Admin） */
  const primaryName = auth.roleDisplay
    ? (auth.user?.fullName ?? '').trim() ||
      (auth.user?.nick ?? auth.user?.userName ?? '').trim() ||
      displayName
    : displayName;
  const roleLine = auth.roleDisplay ?? displayRolesFromCodes(auth.roleCodes);
  const initials = primaryName
    .split(/\s+/)
    .filter(Boolean)
    .slice(0, 2)
    .map((w) => w[0]?.toUpperCase() ?? '')
    .join('') || 'U';

  const currentDate = new Date().toLocaleDateString('en-US', {
    year: 'numeric',
    month: 'long',
    day: 'numeric',
  });

  const searchItems = useMemo(() => buildGlobalMenuSearchItems(menus), [menus]);
  const [searchQuery, setSearchQuery] = useState('');
  const [searchOpen, setSearchOpen] = useState(false);
  const [activeIndex, setActiveIndex] = useState(0);
  const searchWrapRef = useRef<HTMLDivElement>(null);

  const searchResults = useMemo(
    () => filterGlobalMenuSearchItems(searchItems, searchQuery),
    [searchItems, searchQuery],
  );

  const showResults = searchOpen && searchQuery.trim().length > 0 && searchResults.length > 0;

  useEffect(() => {
    setActiveIndex(0);
  }, [searchQuery, searchResults.length]);

  useEffect(() => {
    if (!searchOpen) return;
    const onDocDown = (e: MouseEvent) => {
      if (!searchWrapRef.current?.contains(e.target as Node)) {
        setSearchOpen(false);
      }
    };
    document.addEventListener('mousedown', onDocDown);
    return () => document.removeEventListener('mousedown', onDocDown);
  }, [searchOpen]);

  const pickResult = (viewKey: string) => {
    onNavigate?.(viewKey);
    setSearchQuery('');
    setSearchOpen(false);
  };

  const onSearchKeyDown = (e: React.KeyboardEvent<HTMLInputElement>) => {
    if (!searchResults.length) {
      if (e.key === 'Escape') setSearchOpen(false);
      return;
    }
    if (e.key === 'ArrowDown') {
      e.preventDefault();
      setActiveIndex((i) => (i + 1) % searchResults.length);
      return;
    }
    if (e.key === 'ArrowUp') {
      e.preventDefault();
      setActiveIndex((i) => (i - 1 + searchResults.length) % searchResults.length);
      return;
    }
    if (e.key === 'Enter') {
      e.preventDefault();
      const item = searchResults[activeIndex];
      if (item) pickResult(item.viewKey);
      return;
    }
    if (e.key === 'Escape') {
      setSearchOpen(false);
    }
  };

  return (
    <header className="bg-white border-b border-gray-200 px-8 flex items-center justify-between shadow-sm sticky top-0 z-10 shrink-0" style={{ height: 90 }}>
      <div>
        <h1 className="text-2xl font-bold" style={{ color: 'rgb(43, 50, 143)' }}>{title} Overview</h1>
        <p className="text-sm text-gray-500 mt-1 flex items-center gap-2">
          {currentDate} | Last updated:{' '}
          {auth.loading && !auth.user?.lastUpdated
            ? '…'
            : formatRelativeSince(auth.user?.lastUpdated ?? null)}
        </p>
      </div>

      <div className="flex items-center gap-4">
        <div ref={searchWrapRef} className="relative">
          <div
            className={cn(
              'flex items-center w-64 h-9 rounded-md border border-gray-200 bg-gray-50 transition-colors overflow-hidden',
              searchOpen && 'bg-white ring-2 ring-ring/50 border-ring',
            )}
          >
            <Search className="h-4 w-4 text-gray-400 shrink-0 ml-3 pointer-events-none" />
            <Input
              type="search"
              placeholder="Search..."
              value={searchQuery}
              onChange={(e) => {
                setSearchQuery(e.target.value);
                setSearchOpen(true);
              }}
              onFocus={() => setSearchOpen(true)}
              onKeyDown={onSearchKeyDown}
              className="flex-1 min-w-0 border-0 bg-transparent focus-visible:ring-0 focus-visible:ring-offset-0 py-2 px-2 h-full"
              aria-label="Search menus"
              aria-expanded={showResults}
              aria-autocomplete="list"
              role="combobox"
            />
          </div>

          {showResults && (
            <ul
              className="absolute left-0 right-0 top-full mt-1 max-h-72 overflow-y-auto rounded-md border border-gray-200 bg-white py-1 shadow-lg z-50"
              role="listbox"
            >
              {searchResults.map((item, index) => (
                <li key={item.viewKey} role="option" aria-selected={index === activeIndex}>
                  <button
                    type="button"
                    className={cn(
                      'w-full px-3 py-2 text-left transition-colors',
                      index === activeIndex ? 'bg-blue-50' : 'hover:bg-gray-50',
                    )}
                    onMouseEnter={() => setActiveIndex(index)}
                    onClick={() => pickResult(item.viewKey)}
                  >
                    <div className="text-sm font-medium text-gray-900">{item.label}</div>
                    {item.breadcrumb ? (
                      <div className="text-xs text-gray-500 mt-0.5 truncate">{item.breadcrumb}</div>
                    ) : null}
                  </button>
                </li>
              ))}
            </ul>
          )}
        </div>

        <Button
          type="button"
          variant="ghost"
          size="icon"
          className="text-gray-500 hover:text-gray-700"
          aria-label="Open Support"
          onClick={() => onSettingsClick?.()}
        >
          <Settings className="w-5 h-5" />
        </Button>

        <div className="h-8 w-px bg-gray-200 mx-2" />

        <button
          type="button"
          onClick={() => onProfileClick?.()}
          className="flex items-center gap-3 rounded-lg border border-transparent px-2 py-1.5 text-left transition-colors hover:border-gray-200 hover:bg-gray-50 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-blue-500/40"
          aria-label="Open my profile"
        >
          <div className="text-right hidden md:block min-w-0 max-w-[12rem]">
            <div className="text-sm font-medium text-gray-900 truncate">{primaryName}</div>
            <div className="text-xs text-gray-500 truncate" title={roleLine}>
              {roleLine}
            </div>
          </div>
          <Avatar className="h-10 w-10 shrink-0 border border-gray-200">
            <AvatarImage src="https://github.com/shadcn.png" />
            <AvatarFallback>{initials}</AvatarFallback>
          </Avatar>
        </button>
      </div>
    </header>
  );
}