import React, { useEffect, useState } from 'react';
import { apiClient } from '../services/api';
import Chart from '../components/Chart';
import './Dashboard.css';

interface HealthData {
  date: string;
  steps?: number;
  heartRate?: number;
  sleep?: {
    duration: number;
    quality: number;
  };
  caloriesBurned?: number;
}

function Dashboard() {
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string>('');
  const [summary, setSummary] = useState<HealthData[]>([]);
  const [today, setToday] = useState<HealthData | null>(null);
  const [stats, setStats] = useState({
    avgSteps: 0,
    avgHeartRate: 0,
    avgSleep: 0,
    totalCalories: 0,
  });

  useEffect(() => {
    loadData();
  }, []);

  const loadData = async () => {
    try {
      setLoading(true);
      setError('');

      // Load 30-day summary
      const now = new Date();
      const thirtyDaysAgo = new Date(now.getTime() - 30 * 24 * 60 * 60 * 1000);

      const startDate = thirtyDaysAgo.toISOString().split('T')[0];
      const endDate = now.toISOString().split('T')[0];

      const response = await apiClient.getHealthSummary(startDate, endDate);
      const data = response.data.data || [];

      setSummary(data);

      // Get today's data
      const todayData = data.find((d: HealthData) => d.date === endDate);
      setToday(todayData || null);

      // Calculate stats
      const validData = data.filter((d: HealthData) => d.steps || d.heartRate);
      if (validData.length > 0) {
        const avgSteps =
          Math.round(
            validData.reduce((sum: number, d: HealthData) => sum + (d.steps || 0), 0) /
              validData.length
          ) || 0;

        const heartRates = validData
          .map((d: HealthData) => d.heartRate)
          .filter((hr) => hr);
        const avgHeartRate =
          heartRates.length > 0
            ? Math.round(heartRates.reduce((a, b) => a + b, 0) / heartRates.length)
            : 0;

        const sleeps = validData
          .map((d: HealthData) => d.sleep?.duration)
          .filter((s) => s);
        const avgSleep =
          sleeps.length > 0
            ? Math.round((sleeps.reduce((a, b) => a + b, 0) / sleeps.length) * 10) / 10
            : 0;

        const totalCalories = Math.round(
          validData.reduce((sum: number, d: HealthData) => sum + (d.caloriesBurned || 0), 0)
        );

        setStats({ avgSteps, avgHeartRate, avgSleep, totalCalories });
      }

      setLoading(false);
    } catch (err: any) {
      const errorMsg = err.response?.data?.error?.message || 'Failed to load data';
      setError(errorMsg);
      setLoading(false);
    }
  };

  if (loading) {
    return <div className="page-loading">⏳ 加载中...</div>;
  }

  return (
    <div className="page">
      <h2>📊 健康仪表板</h2>

      {error && <div className="error-message">{error}</div>}

      {/* Today's Summary */}
      {today ? (
        <div className="today-summary">
          <h3>今日概览</h3>
          <div className="stats-grid">
            <div className="stat-card">
              <div className="stat-icon">🚶</div>
              <div className="stat-content">
                <div className="stat-label">步数</div>
                <div className="stat-value">{today.steps || '-'}</div>
              </div>
            </div>

            <div className="stat-card">
              <div className="stat-icon">❤️</div>
              <div className="stat-content">
                <div className="stat-label">心率</div>
                <div className="stat-value">{today.heartRate || '-'} bpm</div>
              </div>
            </div>

            <div className="stat-card">
              <div className="stat-icon">😴</div>
              <div className="stat-content">
                <div className="stat-label">睡眠</div>
                <div className="stat-value">{today.sleep?.duration || '-'} 小时</div>
              </div>
            </div>

            <div className="stat-card">
              <div className="stat-icon">🔥</div>
              <div className="stat-content">
                <div className="stat-label">卡路里</div>
                <div className="stat-value">{today.caloriesBurned || '-'} kcal</div>
              </div>
            </div>
          </div>
        </div>
      ) : (
        <div className="placeholder">暂无今日数据</div>
      )}

      {/* 30-Day Statistics */}
      <div className="statistics">
        <h3>30 日统计</h3>
        <div className="stats-grid">
          <div className="stat-card">
            <div className="stat-icon">📈</div>
            <div className="stat-content">
              <div className="stat-label">平均步数</div>
              <div className="stat-value">{stats.avgSteps.toLocaleString()}</div>
            </div>
          </div>

          <div className="stat-card">
            <div className="stat-icon">❤️</div>
            <div className="stat-content">
              <div className="stat-label">平均心率</div>
              <div className="stat-value">{stats.avgHeartRate} bpm</div>
            </div>
          </div>

          <div className="stat-card">
            <div className="stat-icon">😴</div>
            <div className="stat-content">
              <div className="stat-label">平均睡眠</div>
              <div className="stat-value">{stats.avgSleep}h</div>
            </div>
          </div>

          <div className="stat-card">
            <div className="stat-icon">🔥</div>
            <div className="stat-content">
              <div className="stat-label">总卡路里消耗</div>
              <div className="stat-value">{stats.totalCalories.toLocaleString()}</div>
            </div>
          </div>
        </div>
      </div>

      {/* Charts */}
      {summary.length > 0 && (
        <div className="charts-section">
          <h3>数据趋势</h3>
          <div className="charts-grid">
            <Chart title="步数" data={summary} type="bar" dataKey="steps" fill="#667eea" />
            <Chart
              title="心率"
              data={summary.filter((d) => d.heartRate)}
              type="line"
              dataKey="heartRate"
              stroke="#ff6b9d"
            />
            <Chart
              title="睡眠时长"
              data={summary.filter((d) => d.sleep)}
              type="line"
              dataKey={(d: any) => d.sleep?.duration}
              stroke="#ffd93d"
            />
            <Chart
              title="卡路里消耗"
              data={summary}
              type="bar"
              dataKey="caloriesBurned"
              fill="#6bcf7f"
            />
          </div>
        </div>
      )}
    </div>
  );
}

export default Dashboard;