/* ============================================================
   Exchange Monitor Dashboard — Frontend Logic
   ============================================================ */

(function() {
'use strict';

// ---- DOM refs ----
const $ = id => document.getElementById(id);

const els = {
  clock:      $('clock'),
  connStatus: $('conn-status'),
  priceBody:  $('price-body'),
  arbBody:    $('arb-body'),
  posBody:    $('positions-body'),
  tradesBody: $('trades-body'),
  statTotal:  $('stat-total'),
  statConv:   $('stat-converged'),
  statDiv:    $('stat-diverged'),
  statFlat:   $('stat-flat'),
  statPos:    $('stat-positions'),
  statCoins:  $('stat-coins'),
  chartCoin:  $('chart-coin'),
  chartExch:  $('chart-exchange'),
  chartCanvas: $('priceChart'),
};

// ---- Clock ----
function updateClock() {
  const now = new Date();
  els.clock.textContent = now.toLocaleTimeString('zh-CN', { hour12: false });
}
setInterval(updateClock, 1000);
updateClock();

// ---- Price table helpers ----
const EXCHANGES = ['Binance', 'HyperLiquid', 'Bitget', 'dYdX'];
const COINS = ['DOGE', 'LINK', 'ONDO', 'OP', 'WIF', 'ARB'];

function formatPrice(p) {
  if (p == null || p <= 0) return '-';
  if (p >= 100) return p.toFixed(2);
  if (p >= 1) return p.toFixed(4);
  return p.toFixed(6);
}

function priceClass(lastPrice, currentPrice) {
  if (lastPrice == null || currentPrice == null) return '';
  if (currentPrice > lastPrice) return 'text-green';
  if (currentPrice < lastPrice) return 'text-red';
  return '';
}

// ---- Price history for chart ----
const priceCache = {}; // coin.exchange -> { last: float, points: [{t,p}] }

// ---- SSE Connection ----
let eventSource = null;

function connectSSE() {
  if (eventSource) {
    eventSource.close();
  }

  eventSource = new EventSource('/events');

  eventSource.addEventListener('connected', () => {
    els.connStatus.textContent = '● 已连接';
    els.connStatus.className = 'status-online';
  });

  eventSource.onerror = () => {
    els.connStatus.textContent = '● 已断开 (重连中...)';
    els.connStatus.className = 'status-offline';
    setTimeout(connectSSE, 3000);
  };

  eventSource.onmessage = (e) => {
    try {
      const msg = JSON.parse(e.data);
      const handler = eventHandlers[msg.event];
      if (handler) handler(msg.data);
    } catch(err) {
      // ignore parse errors
    }
  };
}

// ---- Event Handlers ----
const eventHandlers = {};

eventHandlers.prices = (prices) => {
  if (!prices || prices.length === 0) return;

  // Build table rows
  let html = '';
  let coinsOnline = 0;

  for (const coin of COINS) {
    const row = prices.find(p => p.coin === coin);
    if (!row) {
      html += `<tr><td>${coin}</td>${EXCHANGES.map(() => '<td class="text-dim">-</td>').join('')}</tr>`;
      continue;
    }
    coinsOnline++;

    const cells = EXCHANGES.map(ex => {
      const p = row[ex];
      const sp = row[ex + '_spread'];
      const key = coin + '.' + ex;
      const prev = priceCache[key];
      const curP = p || 0;
      const cls = prev ? priceClass(prev.last, curP) : '';

      // Store for directional arrows next time
      if (prev) {
        prev.last = curP;
      } else {
        priceCache[key] = { last: curP, points: [] };
      }

      // Record for chart
      if (p > 0) {
        const pt = { t: Date.now(), p: p };
        if (!priceCache[key]) priceCache[key] = { last: p, points: [] };
        priceCache[key].points.push(pt);
        if (priceCache[key].points.length > 500) {
          priceCache[key].points = priceCache[key].points.slice(-500);
        }
      }

      let display = formatPrice(p);
      if (sp && sp > 0.01) {
        display += `<span class="text-dim" style="font-size:10px"> (${sp.toFixed(3)}%)</span>`;
      }
      return `<td class="${cls}">${display}</td>`;
    });

    html += `<tr><td><strong>${coin}</strong></td>${cells.join('')}</tr>`;
  }

  els.priceBody.innerHTML = html;

  // Update coin selector if needed
  updateChartSelectors(prices);
};

eventHandlers.arb = (opps) => {
  if (!opps || opps.length === 0) {
    els.arbBody.innerHTML = '<tr><td colspan="5" class="text-dim">暂无套利机会</td></tr>';
    return;
  }

  const html = opps.slice(0, 10).map(opp => {
    const cls = opp.net_profit > 0.1 ? 'text-green' : opp.net_profit > 0.05 ? 'text-yellow' : '';
    return `<tr>
      <td>${opp.coin}</td>
      <td>${opp.direction}</td>
      <td class="text-right">${formatPrice(opp.buy_price)}</td>
      <td class="text-right">${formatPrice(opp.sell_price)}</td>
      <td class="text-right ${cls}"><strong>${opp.net_profit.toFixed(4)}</strong></td>
    </tr>`;
  }).join('');

  els.arbBody.innerHTML = html;
};

eventHandlers.positions = (positions) => {
  if (!positions || positions.length === 0) {
    els.posBody.innerHTML = '<tr><td colspan="6" class="text-dim">无持仓</td></tr>';
    return;
  }

  const html = positions.map(p => `<tr>
    <td><strong>${p.coin}</strong></td>
    <td>${p.direction}</td>
    <td class="text-right">$${p.amount_usd.toFixed(0)}</td>
    <td class="text-right">${p.entry_spread.toFixed(4)}%</td>
    <td class="text-right">${p.scales}</td>
    <td>${p.duration}</td>
  </tr>`).join('');

  els.posBody.innerHTML = html;
};

eventHandlers.stats = (stats) => {
  els.statTotal.textContent = stats.total_trades || 0;
  els.statConv.textContent = stats.converged || 0;
  els.statDiv.textContent = stats.diverged || 0;
  els.statFlat.textContent = stats.flat || 0;
  els.statPos.textContent = stats.open_positions || 0;
  els.statCoins.textContent = stats.coins || 0;
};

// ---- Chart ----
let chart = null;

function initChart() {
  const ctx = els.chartCanvas.getContext('2d');
  chart = new Chart(ctx, {
    type: 'line',
    data: {
      datasets: [{
        label: 'Price',
        data: [],
        borderColor: '#58a6ff',
        backgroundColor: 'rgba(88, 166, 255, 0.1)',
        borderWidth: 2,
        pointRadius: 0,
        fill: true,
        tension: 0.2,
      }]
    },
    options: {
      responsive: true,
      maintainAspectRatio: false,
      animation: { duration: 0 },
      plugins: {
        legend: { display: false },
        tooltip: {
          mode: 'index',
          intersect: false,
          callbacks: {
            title: (items) => {
              if (items.length > 0) {
                const d = new Date(items[0].parsed.x);
                return d.toLocaleTimeString('zh-CN', { hour12: false });
              }
              return '';
            },
            label: (item) => item.parsed.y.toFixed(4),
          }
        }
      },
      scales: {
        x: {
          type: 'linear',
          display: true,
          ticks: {
            color: '#8b949e',
            maxTicksLimit: 10,
            callback: (val) => {
              const d = new Date(val);
              return d.toLocaleTimeString('zh-CN', { hour12: false, hour: '2-digit', minute: '2-digit', second: '2-digit' });
            }
          },
          grid: { color: 'rgba(48, 54, 61, 0.5)' },
        },
        y: {
          display: true,
          ticks: {
            color: '#8b949e',
            callback: (val) => val.toFixed(4),
          },
          grid: { color: 'rgba(48, 54, 61, 0.3)' },
        }
      }
    }
  });
}

function updateChartSelectors(prices) {
  const coinSel = els.chartCoin;
  const exSel = els.chartExch;

  // Populate coins if empty
  if (coinSel.options.length <= 1) {
    const currentCoin = coinSel.value;
    coinSel.innerHTML = '<option value="">-- 选择币种 --</option>';
    for (const row of prices) {
      const opt = document.createElement('option');
      opt.value = row.coin;
      opt.textContent = row.coin;
      coinSel.appendChild(opt);
    }
    // Try to restore selection
    if (currentCoin) {
      coinSel.value = currentCoin;
    } else if (prices.length > 0) {
      coinSel.value = prices[0].coin;
    }
  }

  // Populate exchanges if empty
  if (exSel.options.length <= 1) {
    exSel.innerHTML = '<option value="">-- 选择交易所 --</option>';
    for (const ex of EXCHANGES) {
      const opt = document.createElement('option');
      opt.value = ex;
      opt.textContent = ex;
      exSel.appendChild(opt);
    }
    exSel.value = 'HyperLiquid';
  }

  // Update chart when selections change
  const selectedCoin = coinSel.value;
  const selectedEx = exSel.value;
  if (selectedCoin && selectedEx) {
    updateChart(selectedCoin, selectedEx);
  }
}

function updateChart(coin, exchange) {
  const key = coin + '.' + exchange;
  const cache = priceCache[key];
  if (!cache || !cache.points || cache.points.length < 2) {
    if (chart) {
      chart.data.datasets[0].data = [];
      chart.data.datasets[0].label = `${coin} @ ${exchange}`;
      chart.update('none');
    }
    return;
  }

  const pts = cache.points;
  const data = pts.map(p => ({ x: p.t, y: p.p }));

  if (chart) {
    chart.data.datasets[0].data = data;
    chart.data.datasets[0].label = `${coin} @ ${exchange}`;
    chart.update('none');
  }
}

// ---- Chart controls ----
els.chartCoin.addEventListener('change', () => {
  const coin = els.chartCoin.value;
  const ex = els.chartExch.value;
  if (coin && ex) updateChart(coin, ex);
});

els.chartExch.addEventListener('change', () => {
  const coin = els.chartCoin.value;
  const ex = els.chartExch.value;
  if (coin && ex) updateChart(coin, ex);
});

// ---- Chart auto-refresh ----
let chartRefreshTimer = null;
let chartRefreshInterval = 2000; // refresh chart every 2s

function startChartRefresh() {
  if (chartRefreshTimer) return;
  chartRefreshTimer = setInterval(() => {
    const coin = els.chartCoin.value;
    const ex = els.chartExch.value;
    if (coin && ex) updateChart(coin, ex);
  }, chartRefreshInterval);
}

// ---- Trades loading ----
async function loadTrades() {
  try {
    const resp = await fetch('/api/trades');
    const data = await resp.json();
    const trades = data.trades || [];

    if (trades.length === 0) {
      els.tradesBody.innerHTML = '<tr><td colspan="8" class="text-dim">暂无交易记录</td></tr>';
      return;
    }

    const html = trades.slice(0, 20).map(t => {
      const pnlCls = t.NetPnl > 0 ? 'text-green' : t.NetPnl < 0 ? 'text-red' : '';
      const convCls = t.Convergence === '价差收敛' ? 'text-green' :
                      t.Convergence === '价差发散' ? 'text-red' : 'text-yellow';
      return `<tr>
        <td class="text-dim">${t.ClosedAt ? new Date(t.ClosedAt).toLocaleTimeString('zh-CN', { hour12: false }) : '-'}</td>
        <td><strong>${t.Coin}</strong></td>
        <td>${t.Direction}</td>
        <td class="text-right">${t.EntrySpread ? t.EntrySpread.toFixed(4) : '-'}</td>
        <td class="text-right">${t.ExitSpread ? t.ExitSpread.toFixed(4) : '-'}</td>
        <td class="text-right ${pnlCls}"><strong>${t.NetPnl != null ? t.NetPnl.toFixed(4) : '-'}</strong></td>
        <td class="${convCls}">${t.Convergence || '-'}</td>
        <td>${t.ExitReason || '-'}</td>
      </tr>`;
    }).join('');

    els.tradesBody.innerHTML = html;
  } catch (err) {
    els.tradesBody.innerHTML = '<tr><td colspan="8" class="text-red">加载失败</td></tr>';
  }
}

// ---- Init ----
function init() {
  connectSSE();
  initChart();
  startChartRefresh();
  loadTrades();

  // Refresh trades every 10s
  setInterval(loadTrades, 10000);
}

// Start when DOM ready
if (document.readyState === 'loading') {
  document.addEventListener('DOMContentLoaded', init);
} else {
  init();
}

})();