import { useEffect, useState, useCallback, useRef } from 'react';
import { Row, Col, Spin, Empty } from 'antd';
import {
  UserOutlined,
  SafetyCertificateOutlined,
  FileTextOutlined,
  BellOutlined,
  ThunderboltOutlined,
  SettingOutlined,
  PartitionOutlined,
  ClockCircleOutlined,
  ApartmentOutlined,
  CheckCircleOutlined,
  RightOutlined,
} from '@ant-design/icons';
import { useNavigate } from 'react-router-dom';
import client from '../api/client';
import { useThemeMode } from '../hooks/useThemeMode';
import { useMessageStore } from '../stores/message';
import { listAuditLogs, type AuditLogItem } from '../api/auditLogs';
import { listPendingTasks, type TaskInfo } from '../api/workflowTasks';

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

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

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>;
}

const ACTION_LABELS: Record<string, string> = {
  create: '创建', update: '更新', delete: '删除',
  login: '登录', user_login: '登录', 'user.login': '登录',
  'user.create': '创建', 'user.update': '更新', 'user.delete': '删除',
  'role.create': '创建', 'role.update': '更新', 'role.delete': '删除',
  'patient.create': '创建', 'patient.update': '更新',
  'appointment.create': '创建', 'appointment.update': '更新',
};
const RESOURCE_LABELS: Record<string, string> = {
  user: '用户', role: '角色', permission: '权限',
  organization: '组织', department: '部门', position: '岗位',
  dictionary: '字典', menu: '菜单', setting: '设置',
  process_definition: '流程定义', process_instance: '流程实例',
  message: '消息', plugin: '插件',
  patient: '患者', doctor: '医护', appointment: '预约',
  follow_up_task: '随访', consultation_session: '咨询',
  auth: '认证',
};
const RESOURCE_ICONS: Record<string, React.ReactNode> = {
  user: <UserOutlined />, role: <SafetyCertificateOutlined />,
  organization: <ApartmentOutlined />, process_definition: <PartitionOutlined />,
  process_instance: <FileTextOutlined />, message: <BellOutlined />,
  patient: <UserOutlined />, doctor: <UserOutlined />,
};

function formatTimeAgo(dateStr: string): string {
  const diff = Date.now() - new Date(dateStr).getTime();
  const minutes = Math.floor(diff / 60000);
  if (minutes < 1) return '刚刚';
  if (minutes < 60) return `${minutes} 分钟前`;
  const hours = Math.floor(minutes / 60);
  if (hours < 24) return `${hours} 小时前`;
  const days = Math.floor(hours / 24);
  return `${days} 天前`;
}

function formatActionLabel(action: string): string {
  if (ACTION_LABELS[action]) return ACTION_LABELS[action];
  const lastPart = action.split('.').pop() || action;
  return ACTION_LABELS[lastPart] || lastPart;
}

function formatResourceLabel(resource: string): string {
  if (RESOURCE_LABELS[resource]) return RESOURCE_LABELS[resource];
  const lastPart = resource.split('.').pop() || resource;
  return RESOURCE_LABELS[lastPart] || lastPart;
}

export default function Home() {
  const [stats, setStats] = useState<DashboardStats>({
    userCount: 0,
    roleCount: 0,
    processInstanceCount: 0,
    unreadMessages: 0,
  });
  const [loading, setLoading] = useState(true);
  const [pendingTasks, setPendingTasks] = useState<TaskInfo[]>([]);
  const [recentActivities, setRecentActivities] = useState<AuditLogItem[]>([]);
  const [activitiesLoading, setActivitiesLoading] = useState(true);
  const unreadCount = useMessageStore((s) => s.unreadCount);
  const fetchUnreadCount = useMessageStore((s) => s.fetchUnreadCount);
  const navigate = useNavigate();

  const isDark = useThemeMode();

  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);
      }
    }

    async function loadTasks() {
      try {
        const result = await listPendingTasks(1, 5);
        if (!cancelled) setPendingTasks(result.data);
      } catch {
        // 静默处理
      }
    }

    async function loadActivities() {
      setActivitiesLoading(true);
      try {
        const result = await listAuditLogs({ page: 1, page_size: 5 });
        if (!cancelled) setRecentActivities(result.data);
      } catch {
        // 静默处理
      } finally {
        if (!cancelled) setActivitiesLoading(false);
      }
    }

    fetchUnreadCount();
    loadStats();
    loadTasks();
    loadActivities();

    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, #2563eb, #60a5fa)',
      iconBg: 'rgba(79, 70, 229, 0.12)',
      delay: 'erp-fade-in erp-fade-in-delay-1',
      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',
      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',
      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',
      onClick: () => handleNavigate('/messages'),
    },
  ];

  const quickActions = [
    { icon: <UserOutlined />, label: '用户管理', path: '/users', color: '#2563eb' },
    { 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: '#475569' },
  ];

  return (
    <div>
      {/* 欢迎语 */}
      <div className="erp-fade-in" style={{ marginBottom: 24 }}>
        <h2 style={{
          fontSize: 24,
          fontWeight: 700,
          color: isDark ? '#f8fafc' : 'rgba(0,0,0,0.95)',
          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) => (
          <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>
                <div className="erp-stat-card-icon">{card.icon}</div>
              </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: '#2563eb' }} />
              <span className="erp-section-title">待办任务</span>
              <span style={{
                marginLeft: 'auto',
                fontSize: 12,
                color: isDark ? '#94a3b8' : '#475569',
              }}>
                {pendingTasks.length} 项待处理
              </span>
            </div>
            <div className="erp-task-list">
              {pendingTasks.length === 0 ? (
                <Empty description="暂无待办任务" image={Empty.PRESENTED_IMAGE_SIMPLE} />
              ) : (
                pendingTasks.map((task) => (
                  <div
                    key={task.id}
                    className="erp-task-item"
                    style={{ '--task-color': '#2563eb' } as React.CSSProperties}
                    onClick={() => handleNavigate('/workflow')}
                    role="button"
                    tabIndex={0}
                    onKeyDown={(e) => { if (e.key === 'Enter') handleNavigate('/workflow'); }}
                  >
                    <div className="erp-task-item-icon"><PartitionOutlined /></div>
                    <div className="erp-task-item-content">
                      <div className="erp-task-item-title">{task.node_name || task.definition_name || '流程任务'}</div>
                      <div className="erp-task-item-meta">
                        <span>{task.definition_name || '工作流'}</span>
                        <span>{task.status === 'pending' ? '待处理' : task.status}</span>
                      </div>
                    </div>
                    <span className="erp-task-priority erp-task-priority-medium">一般</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: '#60a5fa' }} />
              <span className="erp-section-title">最近动态</span>
            </div>
            <div className="erp-activity-list">
              {activitiesLoading ? (
                <div style={{ textAlign: 'center', padding: 24 }}><Spin /></div>
              ) : recentActivities.length === 0 ? (
                <Empty description="暂无动态" image={Empty.PRESENTED_IMAGE_SIMPLE} />
              ) : (
                recentActivities.map((log) => (
                  <div key={log.id} className="erp-activity-item">
                    <div className="erp-activity-dot">
                      {RESOURCE_ICONS[log.resource_type] || <FileTextOutlined />}
                    </div>
                    <div className="erp-activity-content">
                      <div className="erp-activity-text">
                        {formatActionLabel(log.action)}了{formatResourceLabel(log.resource_type)}
                      </div>
                      <div className="erp-activity-time">{formatTimeAgo(log.created_at)}</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: '#60a5fa' }} />
              <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 18' },
                { label: '缓存', value: 'Redis 7' },
                { label: '前端框架', value: 'React 19 + Ant Design 6' },
                { label: '模块数量', value: '6 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>
  );
}
