const $ = id => document.getElementById(id);
let lastResult = null;

function log(msg, cls = "") {
  const line = document.createElement("div");
  line.textContent = msg;
  if (cls) line.className = cls;
  $("log").appendChild(line);
  $("log").scrollTop = $("log").scrollHeight;
}

function setStatus(online) {
  $("status").textContent = online ? "● ONLINE" : "● OFFLINE";
  $("status").className = online ? "status online" : "status offline";
}

function fmt(n) {
  return Number(n || 0).toLocaleString("en-IN", {
    minimumFractionDigits: 2,
    maximumFractionDigits: 2
  });
}

function fmtDate(s) {
  if (!s) return "";
  return new Date(`${s}T00:00:00Z`).toLocaleDateString("en-IN", {
    day: "2-digit", month: "short", year: "numeric", timeZone: "UTC"
  });
}

function initDates() {
  const today = new Date();
  const end = new Date(Date.UTC(today.getUTCFullYear(), today.getUTCMonth(), today.getUTCDate()));
  const start = new Date(end);
  start.setUTCDate(start.getUTCDate() - 30);
  $("start").value = start.toISOString().slice(0,10);
  $("end").value = end.toISOString().slice(0,10);
}

async function refreshStatus() {
  try {
    const r = await fetch("/api/status");
    const d = await r.json();
    setStatus(Boolean(d.connected));
  } catch {
    setStatus(false);
  }
}

$("loginLink").onclick = async () => {
  try {
    const r = await fetch("/api/login-url");
    const d = await r.json();
    if (!d.url) throw new Error(d.error || "Login URL unavailable");
    window.open(d.url, "_blank", "noopener,noreferrer");
    log("> ICICI Direct login opened", "ok");
  } catch (e) {
    log("> " + e.message, "error");
  }
};

$("connect").onclick = async () => {
  const apiSession = $("session").value.trim();
  if (!apiSession) {
    log("> API Session is required", "error");
    return;
  }

  $("connect").disabled = true;
  $("log").textContent = "";
  log("> POST /api/connect");
  log("> generating Breeze session …");

  try {
    const r = await fetch("/api/connect", {
      method: "POST",
      headers: {"Content-Type":"application/json"},
      body: JSON.stringify({ apiSession })
    });
    const d = await r.json();
    if (!r.ok) throw new Error(d.error || "Breeze connection failed");
    log("> generate_session → OK", "ok");
    log("> BREEZE SESSION ESTABLISHED", "ok");
    setStatus(true);
  } catch (e) {
    setStatus(false);
    log("> " + e.message, "error");
  } finally {
    $("connect").disabled = false;
  }
};

$("logout").onclick = async () => {
  await fetch("/api/logout", {method:"POST"});
  $("session").value = "";
  $("log").textContent = "/ session cleared";
  setStatus(false);
};

function renderMetrics(m) {
  const cards = [
    ["TOTAL LEGS", m.trades],
    ["WIN RATE", `${Number(m.winRate).toFixed(2)}%`],
    ["NET P&L", `₹ ${fmt(m.netPnl)}`],
    ["PROFIT FACTOR", m.profitFactor == null ? "∞" : Number(m.profitFactor).toFixed(2)],
    ["MAX DRAWDOWN", `₹ ${fmt(m.maxDrawdown)}`],
    ["EXPECTANCY / LEG", `₹ ${fmt(m.expectancy)}`],
    ["GROSS PROFIT", `₹ ${fmt(m.grossProfit)}`],
    ["GROSS LOSS", `₹ ${fmt(m.grossLoss)}`],
    ["BROKERAGE", `₹ ${fmt(m.brokerage)}`],
    ["WINS", m.wins],
    ["LOSSES", m.losses]
  ];
  $("metrics").innerHTML = cards.map(([a,b]) =>
    `<div class="metric"><div class="label">${a}</div><div class="value">${b}</div></div>`
  ).join("");
}

function renderTables(r) {
  $("dailyTable").innerHTML = `
    <thead><tr>
      <th>ENTRY</th><th>EXIT</th><th>P&L</th><th>CUMULATIVE</th><th>RESULT</th>
    </tr></thead>
    <tbody>${r.daily.map(d => `
      <tr>
        <td>${fmtDate(d.entryDate)} ${d.entryTime}</td>
        <td>${fmtDate(d.exitDate)} ${d.exitTime}</td>
        <td class="${d.pnl >= 0 ? "pos":"neg"}">₹ ${fmt(d.pnl)}</td>
        <td class="${d.cum >= 0 ? "pos":"neg"}">₹ ${fmt(d.cum)}</td>
        <td>${d.result}</td>
      </tr>`).join("")}</tbody>`;

  $("tradesTable").innerHTML = `
    <thead><tr>
      <th>ENTRY</th><th>EXIT</th><th>RIGHT</th><th>STRIKE</th><th>EXPIRY</th>
      <th>ENTRY ₹</th><th>EXIT ₹</th><th>GROSS</th><th>NET</th><th>REASON</th>
    </tr></thead>
    <tbody>${r.trades.map(t => `
      <tr>
        <td>${fmtDate(t.entryDate)} ${t.entryTime}</td>
        <td>${fmtDate(t.exitDate)} ${t.exitTime}</td>
        <td>${t.right}</td><td>${t.strike}</td><td>${fmtDate(t.expiry)}</td>
        <td>${fmt(t.entry)}</td><td>${fmt(t.exit)}</td>
        <td class="${t.gross >= 0 ? "pos":"neg"}">₹ ${fmt(t.gross)}</td>
        <td class="${t.net >= 0 ? "pos":"neg"}">₹ ${fmt(t.net)}</td>
        <td>${t.reason}</td>
      </tr>`).join("")}</tbody>`;
}

function downloadCSV(filename, rows) {
  const csv = rows.map(row => row.map(v => {
    const s = String(v ?? "");
    return /[",\n]/.test(s) ? `"${s.replaceAll('"','""')}"` : s;
  }).join(",")).join("\n");
  const blob = new Blob([csv], {type:"text/csv;charset=utf-8"});
  const a = document.createElement("a");
  a.href = URL.createObjectURL(blob);
  a.download = filename;
  a.click();
  URL.revokeObjectURL(a.href);
}

$("run").onclick = async () => {
  const start = $("start").value;
  const end = $("end").value;
  if (!start || !end || start > end) {
    alert("Check the backtest date range.");
    return;
  }

  $("run").disabled = true;
  $("run").textContent = "⏳ FETCHING REAL DATA…";
  $("progress").classList.remove("hidden");
  $("bar").style.width = "10%";
  $("progressText").textContent = "Requesting Breeze historical candles…";

  try {
    const r = await fetch("/api/backtest", {
      method: "POST",
      headers: {"Content-Type":"application/json"},
      body: JSON.stringify({
        start,
        end,
        targetPts: Number($("target").value || 20),
        slPts: Number($("sl").value || 10),
        brokerage: Number($("brokerage").value || 40),
        sqOff: $("sqoff").value || "15:10"
      })
    });

    const d = await r.json();
    if (!r.ok) throw new Error(d.error || "Backtest failed");

    lastResult = d;
    $("bar").style.width = "100%";
    $("progressText").textContent = `REAL DATA COMPLETE · ${d.trades.length} LEGS`;
    renderMetrics(d.metrics);
    renderTables(d);
    $("results").classList.remove("hidden");
  } catch (e) {
    alert(e.message);
    $("progressText").textContent = "ERROR: " + e.message;
  } finally {
    setTimeout(() => $("progress").classList.add("hidden"), 700);
    $("run").disabled = false;
    $("run").textContent = "▶ RUN REAL BREEZE BACKTEST";
  }
};

$("downloadTrades").onclick = () => {
  if (!lastResult) return;
  const rows = [
    ["Entry Date","Entry Time","Exit Date","Exit Time","Right","Strike","Expiry","Entry","Exit","Gross","Brokerage","Net","Reason"],
    ...lastResult.trades.map(t => [
      t.entryDate,t.entryTime,t.exitDate,t.exitTime,t.right,t.strike,t.expiry,
      t.entry,t.exit,t.gross,t.brokerage,t.net,t.reason
    ])
  ];
  downloadCSV("nifty_real_breeze_trades.csv", rows);
};

$("downloadDaily").onclick = () => {
  if (!lastResult) return;
  const rows = [
    ["Entry Date","Entry Time","Exit Date","Exit Time","P&L","Cumulative","Result"],
    ...lastResult.daily.map(d => [
      d.entryDate,d.entryTime,d.exitDate,d.exitTime,d.pnl,d.cum,d.result
    ])
  ];
  downloadCSV("nifty_real_breeze_daily.csv", rows);
};

initDates();
refreshStatus();