import { useEffect, useState, useCallback, useRef } from 'react';
import { Row, Col, Spin, theme } from 'antd';
import {
  UserOutlined,
  SafetyCertificateOutlined,
  FileTextOutlined,
  BellOutlined,
  ThunderboltOutlined,
  SettingOutlined,
  PartitionOutlined,
  ClockCircleOutlined,
  ApartmentOutlined,
  CheckCircleOutlined,
  TeamOutlined,
  FileProtectOutlined,
  RiseOutlined,
  FallOutlined,
  RightOutlined,
} from '@ant-design/icons';
import { useNavigate } from 'react-router-dom';
import client from '../api/client';
import { useMessageStore } from '../stores/message';

interface DashboardStats {
  userCount: number;
  roleCount: number;
  processInstanceCount: number;
  unreadMessages: number;
}

interface TrendData {
  value: string;
  direction: 'up' | 'down' | 'neutral';
  label: string;
}

interface StatCardConfig {
  key: string;
  title: string;
  value: number;
  icon: React.ReactNode;
  gradient: string;
  iconBg: string;
  delay: string;
  trend: TrendData;
  sparkline: number[];
  onClick?: () => void;
}

interface TaskItem {
  id: string;
  title: string;
  priority: 'high' | 'medium' | 'low';
  assignee: string;
  dueText: string;
  color: string;
  icon: React.ReactNode;
  path: string;
}

interface ActivityItem {
  id: string;
  text: string;
  time: string;
  icon: React.ReactNode;
}

function useCountUp(end: number, duration = 800) {
  const [count, setCount] = useState(0);
  const prevEnd = useRef(end);

  useEffect(() => {
    if (end === prevEnd.current && count > 0) return;
    prevEnd.current = end;

    if (end === 0) { setCount(0); return; }

    const startTime = performance.now();
    const startVal = 0;

    function tick(now: number) {
      const elapsed = now - startTime;
      const progress = Math.min(elapsed / duration, 1);
      const eased = 1 - Math.pow(1 - progress, 3);
      setCount(Math.round(startVal + (end - startVal) * eased));
      if (progress < 1) requestAnimationFrame(tick);
    }

    requestAnimationFrame(tick);
  }, [end, duration]);

  return count;
}

function StatValue({ value, loading }: { value: number; loading: boolean }) {
  const animatedValue = useCountUp(value);
  if (loading) return <Spin size="small" />;
  return <span className="erp-count-up">{animatedValue.toLocaleString()}</span>;
}

export default function Home() {
  const [stats, setStats] = useState<DashboardStats>({
    userCount: 0,
    roleCount: 0,
    processInstanceCount: 0,
    unreadMessages: 0,
  });
  const [loading, setLoading] = useState(true);
  const unreadCount = useMessageStore((s) => s.unreadCount);
  const fetchUnreadCount = useMessageStore((s) => s.fetchUnreadCount);
  const { token } = theme.useToken();
  const navigate = useNavigate();

  const isDark = token.colorBgContainer === '#111827' || token.colorBgContainer === 'rgb(17, 24, 39)';

  useEffect(() => {
    let cancelled = false;

    async function loadStats() {
      setLoading(true);
      try {
        const [usersRes, rolesRes, instancesRes] = await Promise.allSettled([
          client.get('/users', { params: { page: 1, page_size: 1 } }),
          client.get('/roles', { params: { page: 1, page_size: 1 } }),
          client.get('/workflow/instances', { params: { page: 1, page_size: 1 } }),
        ]);

        if (cancelled) return;

        const extractTotal = (res: PromiseSettledResult<{ data: { data?: { total?: number } } }>) => {
          if (res.status !== 'fulfilled') return 0;
          const body = res.value.data;
          if (body && typeof body === 'object' && 'data' in body) {
            const inner = (body as { data?: { total?: number } }).data;
            return inner?.total ?? 0;
          }
          return 0;
        };

        setStats({
          userCount: extractTotal(usersRes),
          roleCount: extractTotal(rolesRes),
          processInstanceCount: extractTotal(instancesRes),
          unreadMessages: unreadCount,
        });
      } catch {
        // 静默处理
      } finally {
        if (!cancelled) setLoading(false);
      }
    }

    fetchUnreadCount();
    loadStats();

    return () => { cancelled = true; };
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  const handleNavigate = useCallback((path: string) => {
    navigate(path);
  }, [navigate]);

  const statCards: StatCardConfig[] = [
    {
      key: 'users',
      title: '用户总数',
      value: stats.userCount,
      icon: <UserOutlined />,
      gradient: 'linear-gradient(135deg, #4F46E5, #6366F1)',
      iconBg: 'rgba(79, 70, 229, 0.12)',
      delay: 'erp-fade-in erp-fade-in-delay-1',
      trend: { value: '+2', direction: 'up', label: '较上周' },
      sparkline: [30, 45, 35, 50, 40, 55, 60, 50, 65, 70],
      onClick: () => handleNavigate('/users'),
    },
    {
      key: 'roles',
      title: '角色数量',
      value: stats.roleCount,
      icon: <SafetyCertificateOutlined />,
      gradient: 'linear-gradient(135deg, #059669, #10B981)',
      iconBg: 'rgba(5, 150, 105, 0.12)',
      delay: 'erp-fade-in erp-fade-in-delay-2',
      trend: { value: '+1', direction: 'up', label: '较上月' },
      sparkline: [20, 25, 30, 28, 35, 40, 38, 42, 45, 50],
      onClick: () => handleNavigate('/roles'),
    },
    {
      key: 'processes',
      title: '流程实例',
      value: stats.processInstanceCount,
      icon: <FileTextOutlined />,
      gradient: 'linear-gradient(135deg, #D97706, #F59E0B)',
      iconBg: 'rgba(217, 119, 6, 0.12)',
      delay: 'erp-fade-in erp-fade-in-delay-3',
      trend: { value: '0', direction: 'neutral', label: '较昨日' },
      sparkline: [10, 15, 12, 20, 18, 25, 22, 28, 24, 20],
      onClick: () => handleNavigate('/workflow'),
    },
    {
      key: 'messages',
      title: '未读消息',
      value: stats.unreadMessages,
      icon: <BellOutlined />,
      gradient: 'linear-gradient(135deg, #E11D48, #F43F5E)',
      iconBg: 'rgba(225, 29, 72, 0.12)',
      delay: 'erp-fade-in erp-fade-in-delay-4',
      trend: { value: '0', direction: 'neutral', label: '全部已读' },
      sparkline: [5, 8, 3, 10, 6, 12, 8, 4, 7, 5],
      onClick: () => handleNavigate('/messages'),
    },
  ];

  const quickActions = [
    { icon: <UserOutlined />, label: '用户管理', path: '/users', color: '#4F46E5' },
    { icon: <SafetyCertificateOutlined />, label: '权限管理', path: '/roles', color: '#059669' },
    { icon: <ApartmentOutlined />, label: '组织架构', path: '/organizations', color: '#D97706' },
    { icon: <PartitionOutlined />, label: '工作流', path: '/workflow', color: '#7C3AED' },
    { icon: <BellOutlined />, label: '消息中心', path: '/messages', color: '#E11D48' },
    { icon: <SettingOutlined />, label: '系统设置', path: '/settings', color: '#64748B' },
  ];

  const pendingTasks: TaskItem[] = [
    { id: '1', title: '审核新用户注册申请', priority: 'high', assignee: '系统', dueText: '待处理', color: '#DC2626', icon: <UserOutlined />, path: '/users' },
    { id: '2', title: '配置工作流审批节点', priority: 'medium', assignee: '管理员', dueText: '进行中', color: '#D97706', icon: <PartitionOutlined />, path: '/workflow' },
    { id: '3', title: '更新角色权限策略', priority: 'low', assignee: '管理员', dueText: '计划中', color: '#059669', icon: <SafetyCertificateOutlined />, path: '/roles' },
  ];

  const recentActivities: ActivityItem[] = [
    { id: '1', text: '系统管理员 创建了 管理员角色', time: '刚刚', icon: <TeamOutlined /> },
    { id: '2', text: '系统管理员 配置了 工作流模板', time: '5 分钟前', icon: <FileProtectOutlined /> },
    { id: '3', text: '系统管理员 更新了 组织架构', time: '10 分钟前', icon: <ApartmentOutlined /> },
    { id: '4', text: '系统管理员 设置了 消息通知偏好', time: '30 分钟前', icon: <BellOutlined /> },
  ];

  const priorityLabel: Record<string, string> = { high: '紧急', medium: '一般', low: '低' };

  return (
    <div>
      {/* 欢迎语 */}
      <div className="erp-fade-in" style={{ marginBottom: 24 }}>
        <h2 style={{
          fontSize: 24,
          fontWeight: 700,
          color: isDark ? '#F1F5F9' : '#0F172A',
          margin: '0 0 4px',
          letterSpacing: '-0.5px',
        }}>
          工作台
        </h2>
        <p style={{ fontSize: 14, color: isDark ? '#94A3B8' : '#475569', margin: 0 }}>
          欢迎回来，这是您的系统概览
        </p>
      </div>

      {/* 统计卡片行 */}
      <Row gutter={[16, 16]} style={{ marginBottom: 24 }}>
        {statCards.map((card) => {
          const maxSpark = Math.max(...card.sparkline, 1);
          return (
            <Col xs={24} sm={12} lg={6} key={card.key}>
              <div
                className={`erp-stat-card ${card.delay}`}
                style={{ '--card-gradient': card.gradient, '--card-icon-bg': card.iconBg } as React.CSSProperties}
                onClick={card.onClick}
                role="button"
                tabIndex={0}
                onKeyDown={(e) => { if (e.key === 'Enter') card.onClick?.(); }}
              >
                <div className="erp-stat-card-bar" />
                <div className="erp-stat-card-body">
                  <div className="erp-stat-card-info">
                    <div className="erp-stat-card-title">{card.title}</div>
                    <div className="erp-stat-card-value">
                      <StatValue value={card.value} loading={loading} />
                    </div>
                    <div className={`erp-stat-card-trend erp-stat-card-trend-${card.trend.direction}`}>
                      {card.trend.direction === 'up' && <RiseOutlined />}
                      {card.trend.direction === 'down' && <FallOutlined />}
                      <span>{card.trend.value}</span>
                      <span className="erp-stat-card-trend-label">{card.trend.label}</span>
                    </div>
                  </div>
                  <div className="erp-stat-card-icon">{card.icon}</div>
                </div>
                <div className="erp-stat-card-sparkline">
                  {card.sparkline.map((v, i) => (
                    <div
                      key={i}
                      className="erp-stat-card-sparkline-bar"
                      style={{
                        height: `${(v / maxSpark) * 100}%`,
                        background: card.gradient,
                      }}
                    />
                  ))}
                </div>
              </div>
            </Col>
          );
        })}
      </Row>

      {/* 待办任务 + 最近活动 */}
      <Row gutter={[16, 16]} style={{ marginBottom: 24 }}>
        {/* 待办任务 */}
        <Col xs={24} lg={14}>
          <div className="erp-content-card erp-fade-in erp-fade-in-delay-2">
            <div className="erp-section-header">
              <CheckCircleOutlined className="erp-section-icon" style={{ color: '#E11D48' }} />
              <span className="erp-section-title">待办任务</span>
              <span style={{
                marginLeft: 'auto',
                fontSize: 12,
                color: isDark ? '#94A3B8' : '#64748B',
              }}>
                {pendingTasks.length} 项待处理
              </span>
            </div>
            <div className="erp-task-list">
              {pendingTasks.map((task) => (
                <div
                  key={task.id}
                  className="erp-task-item"
                  style={{ '--task-color': task.color } as React.CSSProperties}
                  onClick={() => handleNavigate(task.path)}
                  role="button"
                  tabIndex={0}
                  onKeyDown={(e) => { if (e.key === 'Enter') handleNavigate(task.path); }}
                >
                  <div className="erp-task-item-icon">{task.icon}</div>
                  <div className="erp-task-item-content">
                    <div className="erp-task-item-title">{task.title}</div>
                    <div className="erp-task-item-meta">
                      <span>{task.assignee}</span>
                      <span>{task.dueText}</span>
                    </div>
                  </div>
                  <span className={`erp-task-priority erp-task-priority-${task.priority}`}>
                    {priorityLabel[task.priority]}
                  </span>
                  <RightOutlined style={{ color: isDark ? '#475569' : '#CBD5E1', fontSize: 12 }} />
                </div>
              ))}
            </div>
          </div>
        </Col>

        {/* 最近活动 */}
        <Col xs={24} lg={10}>
          <div className="erp-content-card erp-fade-in erp-fade-in-delay-3" style={{ height: '100%' }}>
            <div className="erp-section-header">
              <ClockCircleOutlined className="erp-section-icon" style={{ color: '#6366F1' }} />
              <span className="erp-section-title">最近动态</span>
            </div>
            <div className="erp-activity-list">
              {recentActivities.map((activity) => (
                <div key={activity.id} className="erp-activity-item">
                  <div className="erp-activity-dot">{activity.icon}</div>
                  <div className="erp-activity-content">
                    <div className="erp-activity-text">{activity.text}</div>
                    <div className="erp-activity-time">{activity.time}</div>
                  </div>
                </div>
              ))}
            </div>
          </div>
        </Col>
      </Row>

      {/* 快捷入口 + 系统信息 */}
      <Row gutter={[16, 16]}>
        <Col xs={24} lg={16}>
          <div className="erp-content-card erp-fade-in erp-fade-in-delay-3">
            <div className="erp-section-header">
              <ThunderboltOutlined className="erp-section-icon" />
              <span className="erp-section-title">快捷入口</span>
            </div>
            <Row gutter={[12, 12]}>
              {quickActions.map((action) => (
                <Col xs={12} sm={8} md={8} key={action.path}>
                  <div
                    className="erp-quick-action"
                    style={{ '--action-color': action.color } as React.CSSProperties}
                    onClick={() => handleNavigate(action.path)}
                    role="button"
                    tabIndex={0}
                    onKeyDown={(e) => { if (e.key === 'Enter') handleNavigate(action.path); }}
                  >
                    <div className="erp-quick-action-icon">{action.icon}</div>
                    <span className="erp-quick-action-label">{action.label}</span>
                  </div>
                </Col>
              ))}
            </Row>
          </div>
        </Col>

        <Col xs={24} lg={8}>
          <div className="erp-content-card erp-fade-in erp-fade-in-delay-4" style={{ height: '100%' }}>
            <div className="erp-section-header">
              <ClockCircleOutlined className="erp-section-icon" style={{ color: '#6366F1' }} />
              <span className="erp-section-title">系统信息</span>
            </div>
            <div className="erp-system-info-list">
              {[
                { label: '系统版本', value: 'v0.1.0' },
                { label: '后端框架', value: 'Axum 0.8 + Tokio' },
                { label: '数据库', value: 'PostgreSQL 16' },
                { label: '缓存', value: 'Redis 7' },
                { label: '前端框架', value: 'React 19 + Ant Design 6' },
                { label: '模块数量', value: '5 个业务模块' },
              ].map((item) => (
                <div key={item.label} className="erp-system-info-item">
                  <span className="erp-system-info-label">{item.label}</span>
                  <span className="erp-system-info-value">{item.value}</span>
                </div>
              ))}
            </div>
          </div>
        </Col>
      </Row>
    </div>
  );
}