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

// --- Shared utilities ---

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`;
}

const ACTION_LABELS: Record<string, string> = {
  create: '创建', created: '创建', update: '更新', updated: '更新', delete: '删除', deleted: '删除',
  login: '登录', 'user.create': '创建', 'user.update': '更新', 'user.delete': '删除',
};
const RESOURCE_LABELS: Record<string, string> = {
  user: '用户', role: '角色', organization: '组织',
  message: '消息', plugin: '插件', process_instance: '流程实例',
};
const RESOURCE_ICONS: Record<string, React.ReactNode> = {
  user: <UserOutlined />, role: <SafetyCertificateOutlined />,
  organization: <ApartmentOutlined />, process_instance: <FileTextOutlined />,
  message: <BellOutlined />,
};

function formatActionLabel(action: string): string {
  return ACTION_LABELS[action] || ACTION_LABELS[action.split('.').pop() || ''] || action;
}
function formatResourceLabel(resource: string): string {
  return RESOURCE_LABELS[resource] || RESOURCE_LABELS[resource.split('.').pop() || ''] || resource;
}

// --- Dashboard config ---

interface QuickActionDef {
  icon: React.ReactNode;
  label: string;
  path: string;
}

const QUICK_ACTIONS: QuickActionDef[] = [
  { icon: <TeamOutlined />, label: '用户管理', path: '/users' },
  { icon: <SafetyCertificateOutlined />, label: '角色权限', path: '/roles' },
  { icon: <CalendarOutlined />, label: '工作流', path: '/workflow' },
  { icon: <BellOutlined />, label: '消息管理', path: '/messages' },
  { icon: <SettingOutlined />, label: '系统设置', path: '/settings' },
  { icon: <BookOutlined />, label: '审计日志', path: '/settings' },
];

const STAT_BAR_COLORS: string[] = [
  'linear-gradient(90deg, #E07A5F, #E8907A)',
  'linear-gradient(90deg, #81B29A, #8FBF9E)',
  'linear-gradient(90deg, #F2CC8F, #D4B878)',
  'linear-gradient(90deg, #D4A5A5, #C4A0A0)',
];
const STAT_TEXT_COLORS: string[] = ['#E07A5F', '#81B29A', '#F2CC8F', '#D4A5A5'];

interface StatCardDef {
  key: string;
  title: string;
  icon: React.ReactNode;
  value: number;
  path: string;
}

const STATS: StatCardDef[] = [
  { key: 'pending-tasks', title: '待办任务', icon: <PartitionOutlined />, value: 0, path: '/workflow' },
  { key: 'users', title: '系统用户', icon: <TeamOutlined />, value: 0, path: '/users' },
  { key: 'messages', title: '消息通知', icon: <BellOutlined />, value: 0, path: '/messages' },
  { key: 'logs', title: '操作日志', icon: <FileTextOutlined />, value: 0, path: '/settings' },
];

// --- Components ---

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 navigate = useNavigate();
  const isDark = useThemeMode();
  const fetchUnreadCount = useMessageStore((s) => s.fetchUnreadCount);

  const [pendingTasks, setPendingTasks] = useState<TaskInfo[]>([]);
  const [recentActivities, setRecentActivities] = useState<AuditLogItem[]>([]);
  const [activitiesLoading, setActivitiesLoading] = useState(true);
  const [statsLoading, setStatsLoading] = useState(true);

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

    listPendingTasks(1, 5)
      .then((result) => { if (!cancelled) setPendingTasks(result.data); })
      .catch((err) => console.warn('[Home] 获取待办任务失败:', err))
      .finally(() => { if (!cancelled) setStatsLoading(false); });

    listAuditLogs({ page: 1, page_size: 5 })
      .then((result) => {
        if (!cancelled) setRecentActivities(result.data.filter((a) => a.action !== 'login_failed'));
        if (!cancelled) STATS[3].value = result.total;
      })
      .catch((err) => console.warn('[Home] 获取审计日志失败:', err))
      .finally(() => { if (!cancelled) setActivitiesLoading(false); });

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

  // 更新统计值
  STATS[0].value = pendingTasks.length;

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

  return (
    <div>
      {/* 欢迎语 */}
      <div className="erp-fade-in" style={{ marginBottom: 24 }}>
        <h2 style={{
          fontSize: 24,
          fontWeight: 700,
          color: isDark ? '#f8fafc' : 'var(--erp-text-primary)',
          margin: '0 0 4px',
          letterSpacing: '-0.5px',
        }}>
          <SmileOutlined style={{ marginRight: 8, color: '#E07A5F' }} />
          暖记管理后台
        </h2>
        <p style={{ fontSize: 14, color: 'var(--erp-text-secondary)', margin: 0 }}>
          班级管理 · 日记审核 · 成长追踪
        </p>
      </div>

      {/* 统计卡片行 */}
      <div style={{ display: 'grid', gridTemplateColumns: 'repeat(4, 1fr)', gap: 16, marginBottom: 24 }}>
        {STATS.map((def, i) => (
          <div
            key={def.key}
            className={`erp-fade-in erp-fade-in-delay-${i + 1}`}
            style={{
              background: 'var(--erp-bg-card, white)',
              borderRadius: 12,
              border: '1px solid var(--erp-border, #E2E8F0)',
              overflow: 'hidden',
              cursor: 'pointer',
              transition: 'all 0.2s',
            }}
            onClick={() => handleNavigate(def.path)}
            role="button"
            tabIndex={0}
            onKeyDown={(e) => { if (e.key === 'Enter') handleNavigate(def.path); }}
            onMouseEnter={(e) => { e.currentTarget.style.boxShadow = '0 2px 8px rgba(0,0,0,0.06)'; e.currentTarget.style.transform = 'translateY(-1px)'; }}
            onMouseLeave={(e) => { e.currentTarget.style.boxShadow = 'none'; e.currentTarget.style.transform = 'none'; }}
          >
            <div style={{ height: 3, background: STAT_BAR_COLORS[i] || STAT_BAR_COLORS[0] }} />
            <div style={{ padding: '16px 20px' }}>
              <div style={{ fontSize: 12, color: '#94A3B8', marginBottom: 6 }}>{def.title}</div>
              <div style={{ fontSize: 28, fontWeight: 700, lineHeight: 1.2, color: STAT_TEXT_COLORS[i] || STAT_TEXT_COLORS[0] }}>
                <StatValue value={def.value} loading={statsLoading} />
              </div>
            </div>
          </div>
        ))}
      </div>

      {/* 待办任务 + 最近动态 */}
      <Row gutter={[16, 16]} style={{ marginBottom: 24 }}>
        <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" />
              <span className="erp-section-title">待办任务</span>
              <span style={{ marginLeft: 'auto', fontSize: 12, color: 'var(--erp-text-secondary)' }}>
                {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': 'var(--erp-primary)' } 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: 'var(--erp-text-tertiary)', fontSize: 12 }} />
                  </div>
                ))
              )}
            </div>
          </div>
        </Col>

        <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" />
              <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 */}
      <Row gutter={[16, 16]}>
        <Col span={24}>
          <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]}>
              {QUICK_ACTIONS.map((action) => (
                <Col xs={12} sm={8} md={4} key={action.path}>
                  <div
                    className="erp-quick-action"
                    style={{ '--action-color': 'var(--erp-primary)' } 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>
      </Row>

      {/* 暖记介绍卡片 */}
      <Row gutter={[16, 16]} style={{ marginTop: 24 }}>
        <Col span={24}>
          <div className="erp-content-card erp-fade-in erp-fade-in-delay-4" style={{
            background: 'linear-gradient(135deg, #FFF8F0 0%, #FFE8DE 100%)',
            border: '1px solid #F0D5C8',
            borderRadius: 16,
            padding: '24px 32px',
          }}>
            <Row align="middle" gutter={24}>
              <Col flex="auto">
                <h3 style={{ fontSize: 18, fontWeight: 600, color: '#2D2420', margin: '0 0 8px' }}>
                  <HeartOutlined style={{ marginRight: 8, color: '#E07A5F' }} />
                  欢迎使用暖记管理后台
                </h3>
                <p style={{ fontSize: 14, color: '#6B5E52', margin: 0, lineHeight: 1.6 }}>
                  暖记是一款温暖治愈风格的手账日记 App，以手写/涂鸦为核心输入方式，面向小学生首发。
                  通过管理后台可以管理班级、审核日记、追踪学生成长。
                </p>
              </Col>
              <Col>
                <BookOutlined style={{ fontSize: 48, color: '#E07A5F', opacity: 0.3 }} />
              </Col>
            </Row>
          </div>
        </Col>
      </Row>
    </div>
  );
}