'use client';

import { useState, useEffect, useCallback } from 'react';
import * as Icons from './Icons';

interface AnalyticsData {
  trackingEnabled?: boolean;
  summary: {
    totalViews: number;
    lastUpdated: string;
  };
  days: Record<
    string,
    {
      pageviews: number;
      pages: Record<string, number>;
      devices: Record<string, number>;
    }
  >;
  topPages: { path: string; count: number }[];
  devices: { desktop: number; mobile: number };
}

export default function AnalyticsView() {
  const [data, setData] = useState<AnalyticsData | null>(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);

  const fetchAnalytics = useCallback(async () => {
    setLoading(true);
    setError(null);
    try {
      const res = await fetch('/api/admin/analytics');
      if (!res.ok) throw new Error('Failed to fetch analytics');
      const json = await res.json();
      setData(json);
    } catch (err: any) {
      setError(err.message || 'Error loading analytics');
    } finally {
      setLoading(false);
    }
  }, []);

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

  if (loading) {
    return (
      <div className="admin-loading-container">
        <div className="admin-spinner" />
      </div>
    );
  }

  if (error || !data) {
    return (
      <div className="admin-panel" style={{ padding: '2rem', textAlign: 'center' }}>
        <p style={{ color: 'var(--admin-text-muted)', marginBottom: '1rem' }}>
          {error || 'No analytics data'}
        </p>
        <button className="admin-btn admin-btn-primary" onClick={fetchAnalytics}>
          <Icons.IconRefresh size={14} /> Retry
        </button>
      </div>
    );
  }

  const totalViews = data.summary?.totalViews || 0;
  const maxPageViews = data.topPages[0]?.count || 1;
  const daysList = Object.entries(data.days || {})
    .sort((a, b) => a[0].localeCompare(b[0]))
    .slice(-14); // Last 14 days
  const maxDayViews = Math.max(...daysList.map(([, d]) => d.pageviews || 0), 1);

  const desktopRatio =
    data.devices.desktop + data.devices.mobile > 0
      ? Math.round((data.devices.desktop / (data.devices.desktop + data.devices.mobile)) * 100)
      : 50;

  return (
    <div className="analytics-view">
      {/* Header */}
      <div className="analytics-header">
        <div>
          <h2>
            <Icons.IconSparkles size={20} /> Visitor Insights &amp; Analytics
          </h2>
          <p className="analytics-subtitle">
            Privacy-first aggregate traffic stats. No personal data collected.
          </p>
        </div>
        <button className="admin-btn admin-btn-ghost admin-btn-sm" onClick={fetchAnalytics}>
          <Icons.IconRefresh size={14} /> Refresh
        </button>
      </div>

      {data.trackingEnabled === false && (
        <div
          className="backup-status-alert error"
          style={{ margin: 0, display: 'flex', alignItems: 'center', gap: '0.5rem' }}
        >
          <Icons.IconLock size={16} />
          <span>
            <strong>Analytics Tracking is Currently Disabled.</strong> No new visitor views are
            being recorded. You can re-enable tracking anytime under{' '}
            <em>Settings &rarr; General</em>.
          </span>
        </div>
      )}

      {/* Top Metric Cards */}
      <div className="analytics-metrics-grid">
        <div className="metric-card">
          <span className="metric-label">Total Page Views</span>
          <span className="metric-value">{totalViews.toLocaleString()}</span>
          <span className="metric-sub">Lifetime aggregate</span>
        </div>
        <div className="metric-card">
          <span className="metric-label">Active Days Tracked</span>
          <span className="metric-value">{Object.keys(data.days || {}).length}</span>
          <span className="metric-sub">Days recorded</span>
        </div>
        <div className="metric-card">
          <span className="metric-label">Desktop vs Mobile</span>
          <span className="metric-value">
            {desktopRatio}% / {100 - desktopRatio}%
          </span>
          <span className="metric-sub">Device distribution</span>
        </div>
      </div>

      {/* Daily Trends Chart */}
      <div className="analytics-panel">
        <div className="analytics-section-title">
          <h3>
            <Icons.IconGrid size={16} /> Daily Traffic Trend (Last 14 Days)
          </h3>
        </div>
        {daysList.length === 0 ? (
          <p className="analytics-empty">
            No pageviews recorded yet. Visit portfolio pages to start tracking!
          </p>
        ) : (
          <div className="analytics-bar-chart">
            {daysList.map(([dateStr, dayData]) => {
              const heightPct = Math.round((dayData.pageviews / maxDayViews) * 100);
              const formattedDate = dateStr.slice(5); // MM-DD
              return (
                <div
                  key={dateStr}
                  className="bar-col"
                  title={`${dateStr}: ${dayData.pageviews} views`}
                >
                  <div className="bar-wrapper">
                    <div className="bar-fill" style={{ height: `${Math.max(heightPct, 8)}%` }}>
                      <span className="bar-val">{dayData.pageviews}</span>
                    </div>
                  </div>
                  <span className="bar-label">{formattedDate}</span>
                </div>
              );
            })}
          </div>
        )}
      </div>

      {/* Top Pages List */}
      <div className="analytics-panel">
        <div className="analytics-section-title">
          <h3>
            <Icons.IconTarget size={16} /> Top Visited Pages &amp; Subpages
          </h3>
        </div>
        {data.topPages.length === 0 ? (
          <p className="analytics-empty">No pages recorded yet.</p>
        ) : (
          <div className="analytics-top-pages">
            {data.topPages.map((p, idx) => {
              const widthPct = Math.round((p.count / maxPageViews) * 100);
              return (
                <div key={p.path} className="top-page-row">
                  <span className="page-rank">#{idx + 1}</span>
                  <div className="page-info">
                    <div className="page-path-line">
                      <span className="page-path">{p.path}</span>
                      <span className="page-count">{p.count} views</span>
                    </div>
                    <div className="page-progress-bg">
                      <div className="page-progress-fill" style={{ width: `${widthPct}%` }} />
                    </div>
                  </div>
                </div>
              );
            })}
          </div>
        )}
      </div>
    </div>
  );
}