/**
 * OpenHamClock Server
 * 
 * Express server that:
 * 1. Serves the static web application
 * 2. Proxies API requests to avoid CORS issues
 * 3. Provides WebSocket support for future real-time features
 * 
 * Usage:
 *   node server.js
 *   PORT=8080 node server.js
 */

const express = require('express');
const cors = require('cors');
const path = require('path');
const fetch = require('node-fetch');

const app = express();
const PORT = process.env.PORT || 3000;

// Middleware
app.use(cors());
app.use(express.json());

// Serve static files from public directory
app.use(express.static(path.join(__dirname, 'public')));

// ============================================
// API PROXY ENDPOINTS
// ============================================

// NOAA Space Weather - Solar Flux
app.get('/api/noaa/flux', async (req, res) => {
  try {
    const response = await fetch('https://services.swpc.noaa.gov/json/f107_cm_flux.json');
    const data = await response.json();
    res.json(data);
  } catch (error) {
    console.error('NOAA Flux API error:', error.message);
    res.status(500).json({ error: 'Failed to fetch solar flux data' });
  }
});

// NOAA Space Weather - K-Index
app.get('/api/noaa/kindex', async (req, res) => {
  try {
    const response = await fetch('https://services.swpc.noaa.gov/products/noaa-planetary-k-index.json');
    const data = await response.json();
    res.json(data);
  } catch (error) {
    console.error('NOAA K-Index API error:', error.message);
    res.status(500).json({ error: 'Failed to fetch K-index data' });
  }
});

// NOAA Space Weather - Sunspots
app.get('/api/noaa/sunspots', async (req, res) => {
  try {
    const response = await fetch('https://services.swpc.noaa.gov/json/solar-cycle/observed-solar-cycle-indices.json');
    const data = await response.json();
    res.json(data);
  } catch (error) {
    console.error('NOAA Sunspots API error:', error.message);
    res.status(500).json({ error: 'Failed to fetch sunspot data' });
  }
});

// NOAA Space Weather - X-Ray Flux
app.get('/api/noaa/xray', async (req, res) => {
  try {
    const response = await fetch('https://services.swpc.noaa.gov/json/goes/primary/xrays-7-day.json');
    const data = await response.json();
    res.json(data);
  } catch (error) {
    console.error('NOAA X-Ray API error:', error.message);
    res.status(500).json({ error: 'Failed to fetch X-ray data' });
  }
});

// POTA Spots
app.get('/api/pota/spots', async (req, res) => {
  try {
    const response = await fetch('https://api.pota.app/spot/activator');
    const data = await response.json();
    res.json(data);
  } catch (error) {
    console.error('POTA API error:', error.message);
    res.status(500).json({ error: 'Failed to fetch POTA spots' });
  }
});

// SOTA Spots
app.get('/api/sota/spots', async (req, res) => {
  try {
    const response = await fetch('https://api2.sota.org.uk/api/spots/50/all');
    const data = await response.json();
    res.json(data);
  } catch (error) {
    console.error('SOTA API error:', error.message);
    res.status(500).json({ error: 'Failed to fetch SOTA spots' });
  }
});

// HamQSL Band Conditions
app.get('/api/hamqsl/conditions', async (req, res) => {
  try {
    const response = await fetch('https://www.hamqsl.com/solarxml.php');
    const text = await response.text();
    res.set('Content-Type', 'application/xml');
    res.send(text);
  } catch (error) {
    console.error('HamQSL API error:', error.message);
    res.status(500).json({ error: 'Failed to fetch band conditions' });
  }
});

// DX Cluster proxy - fetches from multiple sources
app.get('/api/dxcluster/spots', async (req, res) => {
  console.log('[DX Cluster] Fetching spots...');
  
  // Try DXCluster.co API first (very reliable JSON API)
  try {
    const controller = new AbortController();
    const timeout = setTimeout(() => controller.abort(), 5000);
    
    const response = await fetch('https://dxcluster.co/api/v1/spots?limit=30', {
      headers: { 
        'User-Agent': 'OpenHamClock/3.3',
        'Accept': 'application/json'
      },
      signal: controller.signal
    });
    clearTimeout(timeout);
    
    if (response.ok) {
      const data = await response.json();
      console.log('[DX Cluster] dxcluster.co returned', data.length, 'spots');
      if (data && data.length > 0) {
        const spots = data.slice(0, 20).map(spot => ({
          freq: spot.frequency ? (parseFloat(spot.frequency) / 1000).toFixed(3) : '0.000',
          call: spot.dx_callsign || spot.callsign || 'UNKNOWN',
          comment: spot.comment || '',
          time: spot.time ? spot.time.substring(11, 16) + 'z' : '',
          spotter: spot.spotter_callsign || ''
        }));
        return res.json(spots);
      }
    }
  } catch (error) {
    if (error.name === 'AbortError') {
      console.log('[DX Cluster] dxcluster.co timeout');
    } else {
      console.error('[DX Cluster] dxcluster.co error:', error.message);
    }
  }
  
  // Try DX Heat API
  try {
    const controller = new AbortController();
    const timeout = setTimeout(() => controller.abort(), 5000);
    
    const response = await fetch('https://dxheat.com/dxc/data.php?include_modes=cw,ssb,ft8,ft4,rtty&include_bands=160,80,60,40,30,20,17,15,12,10,6&limit=30', {
      headers: { 
        'User-Agent': 'OpenHamClock/3.3',
        'Accept': 'application/json'
      },
      signal: controller.signal
    });
    clearTimeout(timeout);
    
    if (response.ok) {
      const text = await response.text();
      console.log('[DX Cluster] DXHeat response length:', text.length);
      try {
        const data = JSON.parse(text);
        if (data && data.spots && data.spots.length > 0) {
          const spots = data.spots.map(spot => ({
            freq: spot.f ? (parseFloat(spot.f)).toFixed(3) : '0.000',
            call: spot.c || 'UNKNOWN',
            comment: spot.i || '',
            time: spot.t ? spot.t.substring(11, 16) + 'z' : '',
            spotter: spot.s || ''
          })).slice(0, 20);
          console.log('[DX Cluster] DXHeat returned', spots.length, 'spots');
          return res.json(spots);
        }
      } catch (parseErr) {
        console.log('[DX Cluster] DXHeat parse error:', parseErr.message);
      }
    }
  } catch (error) {
    if (error.name === 'AbortError') {
      console.log('[DX Cluster] DXHeat timeout');
    } else {
      console.error('[DX Cluster] DXHeat error:', error.message);
    }
  }

  // Try RBN (Reverse Beacon Network) API
  try {
    const controller = new AbortController();
    const timeout = setTimeout(() => controller.abort(), 5000);
    
    const response = await fetch('https://reversebeacon.net/api/spots.php?r=30', {
      headers: { 
        'User-Agent': 'OpenHamClock/3.3'
      },
      signal: controller.signal
    });
    clearTimeout(timeout);
    
    if (response.ok) {
      const data = await response.json();
      console.log('[DX Cluster] RBN returned', data?.length || 0, 'spots');
      if (data && data.length > 0) {
        const spots = data.slice(0, 20).map(spot => ({
          freq: spot.freq ? (parseFloat(spot.freq) / 1000).toFixed(3) : '0.000',
          call: spot.dx || spot.callsign || 'UNKNOWN',
          comment: spot.mode ? `${spot.mode} ${spot.db || ''}dB` : '',
          time: spot.time || new Date().toISOString().substring(11, 16) + 'z',
          spotter: spot.de || ''
        }));
        return res.json(spots);
      }
    }
  } catch (error) {
    if (error.name === 'AbortError') {
      console.log('[DX Cluster] RBN timeout');
    } else {
      console.error('[DX Cluster] RBN error:', error.message);
    }
  }

  // Try HamQTH DX Cluster
  try {
    const controller = new AbortController();
    const timeout = setTimeout(() => controller.abort(), 5000);
    
    const response = await fetch('https://www.hamqth.com/dxc_csv.php?limit=30', {
      headers: { 'User-Agent': 'OpenHamClock/3.3' },
      signal: controller.signal
    });
    clearTimeout(timeout);
    
    if (response.ok) {
      const text = await response.text();
      console.log('[DX Cluster] HamQTH response length:', text.length);
      const lines = text.trim().split('\n').filter(line => line.trim());
      
      if (lines.length > 0) {
        const spots = lines.slice(0, 20).map(line => {
          const parts = line.split(',');
          return {
            freq: parts[1] ? (parseFloat(parts[1]) / 1000).toFixed(3) : '0.000',
            call: parts[2] || 'UNKNOWN',
            comment: parts[5] || '',
            time: parts[4] ? parts[4].substring(0, 5) + 'z' : '',
            spotter: parts[3] || ''
          };
        }).filter(s => s.call !== 'UNKNOWN' && s.freq !== '0.000');
        
        if (spots.length > 0) {
          console.log('[DX Cluster] HamQTH returned', spots.length, 'spots');
          return res.json(spots);
        }
      }
    }
  } catch (error) {
    if (error.name === 'AbortError') {
      console.log('[DX Cluster] HamQTH timeout');
    } else {
      console.error('[DX Cluster] HamQTH error:', error.message);
    }
  }

  // Try DXWatch as last resort
  try {
    const controller = new AbortController();
    const timeout = setTimeout(() => controller.abort(), 5000);
    
    const response = await fetch('https://dxwatch.com/dxsd1/s.php?s=0&r=30', {
      headers: { 
        'User-Agent': 'OpenHamClock/3.3',
        'Accept': '*/*'
      },
      signal: controller.signal
    });
    clearTimeout(timeout);
    
    if (response.ok) {
      const text = await response.text();
      console.log('[DX Cluster] DXWatch response length:', text.length);
      try {
        const data = JSON.parse(text);
        if (Array.isArray(data) && data.length > 0) {
          const spots = data.map(spot => ({
            freq: spot.fr ? (parseFloat(spot.fr) / 1000).toFixed(3) : '0.000',
            call: spot.dx || 'UNKNOWN',
            comment: spot.cm || '',
            time: spot.t || '',
            spotter: spot.sp || ''
          })).slice(0, 20);
          console.log('[DX Cluster] DXWatch returned', spots.length, 'spots');
          return res.json(spots);
        }
      } catch (parseErr) {
        console.log('[DX Cluster] DXWatch parse error');
      }
    }
  } catch (error) {
    if (error.name === 'AbortError') {
      console.log('[DX Cluster] DXWatch timeout');
    } else {
      console.error('[DX Cluster] DXWatch error:', error.message);
    }
  }

  console.log('[DX Cluster] All sources failed, returning empty');
  res.json([]);
});

// QRZ Callsign lookup (requires API key)
app.get('/api/qrz/lookup/:callsign', async (req, res) => {
  const { callsign } = req.params;
  // Note: QRZ requires an API key - this is a placeholder
  res.json({ 
    message: 'QRZ lookup requires API key configuration',
    callsign: callsign.toUpperCase()
  });
});

// ============================================
// CONTEST CALENDAR API
// ============================================

app.get('/api/contests', async (req, res) => {
  console.log('[Contests] Fetching contest calendar...');
  
  // Try WA7BNM Contest Calendar API
  try {
    const response = await fetch('https://www.contestcalendar.com/contestcal.json', {
      headers: { 
        'User-Agent': 'OpenHamClock/3.3',
        'Accept': 'application/json'
      }
    });
    
    if (response.ok) {
      const data = await response.json();
      console.log('[Contests] WA7BNM returned', data.length, 'contests');
      
      const now = new Date();
      const contests = data
        .filter(c => new Date(c.end) > now) // Only future/active
        .slice(0, 20)
        .map(c => {
          const startDate = new Date(c.start);
          const endDate = new Date(c.end);
          let status = 'upcoming';
          if (now >= startDate && now <= endDate) {
            status = 'active';
          }
          
          return {
            name: c.name || c.contest,
            start: startDate.toISOString(),
            end: endDate.toISOString(),
            mode: c.mode || 'Mixed',
            status: status,
            url: c.url || null
          };
        });
      
      return res.json(contests);
    }
  } catch (error) {
    console.error('[Contests] WA7BNM error:', error.message);
  }

  // Fallback: Calculate known recurring contests
  try {
    const contests = calculateUpcomingContests();
    console.log('[Contests] Using calculated contests:', contests.length);
    return res.json(contests);
  } catch (error) {
    console.error('[Contests] Calculation error:', error.message);
  }

  res.json([]);
});

// Helper function to calculate upcoming contests
function calculateUpcomingContests() {
  const now = new Date();
  const contests = [];
  
  // Major contest definitions with typical schedules
  const majorContests = [
    { name: 'CQ WW DX CW', month: 10, weekend: -1, duration: 48, mode: 'CW' }, // Last full weekend Nov
    { name: 'CQ WW DX SSB', month: 9, weekend: -1, duration: 48, mode: 'SSB' }, // Last full weekend Oct
    { name: 'ARRL DX CW', month: 1, weekend: 3, duration: 48, mode: 'CW' }, // 3rd full weekend Feb
    { name: 'ARRL DX SSB', month: 2, weekend: 1, duration: 48, mode: 'SSB' }, // 1st full weekend Mar
    { name: 'CQ WPX SSB', month: 2, weekend: -1, duration: 48, mode: 'SSB' }, // Last full weekend Mar
    { name: 'CQ WPX CW', month: 4, weekend: -1, duration: 48, mode: 'CW' }, // Last full weekend May
    { name: 'IARU HF Championship', month: 6, weekend: 2, duration: 24, mode: 'Mixed' }, // 2nd full weekend Jul
    { name: 'ARRL Field Day', month: 5, weekend: 4, duration: 27, mode: 'Mixed' }, // 4th full weekend Jun
    { name: 'ARRL Sweepstakes CW', month: 10, weekend: 1, duration: 24, mode: 'CW' }, // 1st full weekend Nov
    { name: 'ARRL Sweepstakes SSB', month: 10, weekend: 3, duration: 24, mode: 'SSB' }, // 3rd full weekend Nov
    { name: 'ARRL 10m Contest', month: 11, weekend: 2, duration: 48, mode: 'Mixed' }, // 2nd full weekend Dec
    { name: 'ARRL RTTY Roundup', month: 0, weekend: 1, duration: 24, mode: 'RTTY' }, // 1st full weekend Jan
    { name: 'NA QSO Party CW', month: 0, weekend: 2, duration: 12, mode: 'CW' },
    { name: 'NA QSO Party SSB', month: 0, weekend: 3, duration: 12, mode: 'SSB' },
    { name: 'CQ 160m CW', month: 0, weekend: -1, duration: 42, mode: 'CW' },
    { name: 'CQ WW RTTY', month: 8, weekend: -1, duration: 48, mode: 'RTTY' },
    { name: 'JIDX CW', month: 3, weekend: 2, duration: 48, mode: 'CW' },
    { name: 'JIDX SSB', month: 10, weekend: 2, duration: 48, mode: 'SSB' },
  ];

  // Weekly mini-contests (CWT, SST, etc.)
  const weeklyContests = [
    { name: 'CWT 1300z', dayOfWeek: 3, hour: 13, duration: 1, mode: 'CW' },
    { name: 'CWT 1900z', dayOfWeek: 3, hour: 19, duration: 1, mode: 'CW' },
    { name: 'CWT 0300z', dayOfWeek: 4, hour: 3, duration: 1, mode: 'CW' },
    { name: 'NCCC Sprint', dayOfWeek: 5, hour: 3, minute: 30, duration: 0.5, mode: 'CW' },
    { name: 'K1USN SST', dayOfWeek: 0, hour: 0, duration: 1, mode: 'CW' },
    { name: 'ICWC MST', dayOfWeek: 1, hour: 13, duration: 1, mode: 'CW' },
  ];

  // Calculate next occurrences of weekly contests
  weeklyContests.forEach(contest => {
    const next = new Date(now);
    const currentDay = now.getUTCDay();
    let daysUntil = contest.dayOfWeek - currentDay;
    if (daysUntil < 0) daysUntil += 7;
    if (daysUntil === 0) {
      // Check if it's today but already passed
      const todayStart = new Date(now);
      todayStart.setUTCHours(contest.hour, contest.minute || 0, 0, 0);
      if (now > todayStart) daysUntil = 7;
    }
    
    next.setUTCDate(now.getUTCDate() + daysUntil);
    next.setUTCHours(contest.hour, contest.minute || 0, 0, 0);
    
    const endTime = new Date(next.getTime() + contest.duration * 3600000);
    
    contests.push({
      name: contest.name,
      start: next.toISOString(),
      end: endTime.toISOString(),
      mode: contest.mode,
      status: (now >= next && now <= endTime) ? 'active' : 'upcoming'
    });
  });

  // Calculate next occurrences of major contests
  const year = now.getFullYear();
  majorContests.forEach(contest => {
    for (let y = year; y <= year + 1; y++) {
      let startDate;
      
      if (contest.weekend === -1) {
        // Last weekend of month
        startDate = getLastWeekendOfMonth(y, contest.month);
      } else {
        // Nth weekend of month
        startDate = getNthWeekendOfMonth(y, contest.month, contest.weekend);
      }
      
      // Most contests start at 00:00 UTC Saturday
      startDate.setUTCHours(0, 0, 0, 0);
      const endDate = new Date(startDate.getTime() + contest.duration * 3600000);
      
      if (endDate > now) {
        const status = (now >= startDate && now <= endDate) ? 'active' : 'upcoming';
        contests.push({
          name: contest.name,
          start: startDate.toISOString(),
          end: endDate.toISOString(),
          mode: contest.mode,
          status: status
        });
        break; // Only add next occurrence
      }
    }
  });

  // Sort by start date
  contests.sort((a, b) => new Date(a.start) - new Date(b.start));
  
  return contests.slice(0, 15);
}

function getNthWeekendOfMonth(year, month, n) {
  const date = new Date(Date.UTC(year, month, 1, 0, 0, 0));
  let weekendCount = 0;
  
  while (date.getUTCMonth() === month) {
    if (date.getUTCDay() === 6) { // Saturday
      weekendCount++;
      if (weekendCount === n) return new Date(date);
    }
    date.setUTCDate(date.getUTCDate() + 1);
  }
  
  return date;
}

function getLastWeekendOfMonth(year, month) {
  // Start from last day of month and work backwards
  const date = new Date(Date.UTC(year, month + 1, 0)); // Last day of month
  
  while (date.getUTCDay() !== 6) { // Find last Saturday
    date.setUTCDate(date.getUTCDate() - 1);
  }
  
  return date;
}

// ============================================
// HEALTH CHECK
// ============================================

app.get('/api/health', (req, res) => {
  res.json({
    status: 'ok',
    version: '3.3.0',
    uptime: process.uptime(),
    timestamp: new Date().toISOString()
  });
});

// ============================================
// CONFIGURATION ENDPOINT
// ============================================

app.get('/api/config', (req, res) => {
  res.json({
    version: '3.0.0',
    features: {
      spaceWeather: true,
      pota: true,
      sota: true,
      dxCluster: true,
      satellites: false, // Coming soon
      contests: false    // Coming soon
    },
    refreshIntervals: {
      spaceWeather: 300000,
      pota: 60000,
      sota: 60000,
      dxCluster: 30000
    }
  });
});

// ============================================
// CATCH-ALL FOR SPA
// ============================================

app.get('*', (req, res) => {
  res.sendFile(path.join(__dirname, 'public', 'index.html'));
});

// ============================================
// START SERVER
// ============================================

app.listen(PORT, () => {
  console.log('');
  console.log('╔═══════════════════════════════════════════════════════╗');
  console.log('║                                                       ║');
  console.log('║   ██████╗ ██████╗ ███████╗███╗   ██╗                  ║');
  console.log('║  ██╔═══██╗██╔══██╗██╔════╝████╗  ██║                  ║');
  console.log('║  ██║   ██║██████╔╝█████╗  ██╔██╗ ██║                  ║');
  console.log('║  ██║   ██║██╔═══╝ ██╔══╝  ██║╚██╗██║                  ║');
  console.log('║  ╚██████╔╝██║     ███████╗██║ ╚████║                  ║');
  console.log('║   ╚═════╝ ╚═╝     ╚══════╝╚═╝  ╚═══╝                  ║');
  console.log('║                                                       ║');
  console.log('║  ██╗  ██╗ █████╗ ███╗   ███╗ ██████╗██╗      ██╗  ██╗ ║');
  console.log('║  ██║  ██║██╔══██╗████╗ ████║██╔════╝██║      ██║ ██╔╝ ║');
  console.log('║  ███████║███████║██╔████╔██║██║     ██║      █████╔╝  ║');
  console.log('║  ██╔══██║██╔══██║██║╚██╔╝██║██║     ██║      ██╔═██╗  ║');
  console.log('║  ██║  ██║██║  ██║██║ ╚═╝ ██║╚██████╗███████╗██║  ██╗ ║');
  console.log('║  ╚═╝  ╚═╝╚═╝  ╚═╝╚═╝     ╚═╝ ╚═════╝╚══════╝╚═╝  ╚═╝ ║');
  console.log('║                                                       ║');
  console.log('╚═══════════════════════════════════════════════════════╝');
  console.log('');
  console.log(`  🌐 Server running at http://localhost:${PORT}`);
  console.log('  📡 API proxy enabled for NOAA, POTA, SOTA, DX Cluster');
  console.log('  🖥️  Open your browser to start using OpenHamClock');
  console.log('');
  console.log('  In memory of Elwood Downey, WB0OEW');
  console.log('  73 de OpenHamClock contributors');
  console.log('');
});

// Graceful shutdown
process.on('SIGTERM', () => {
  console.log('SIGTERM received, shutting down gracefully');
  process.exit(0);
});

process.on('SIGINT', () => {
  console.log('\nShutting down...');
  process.exit(0);
});