// ============================================================
// BUILD ORDER REQUEST — HMAC-SHA256 signed Binance order
// Pure-JS HMAC (crypto module blocked by n8n task-runner sandbox)
// ============================================================

const API_KEY    = 'kFYcAx3hJjlAtxbtSjl0DuY1s6zIXLm0YNnwhEqueWMkHvOEAkyBfAAGGfJTfoJS';
const SECRET_KEY = 'x7Em12CzxC7bTWmCUah7W6Q8DAFiZgXkmzRRLJnxnaJyAdmQtcCkU4Spun7QjYMt';
const ORDER_PATH = '/api/v3/order';          // LIVE — real orders

function sha256(msgBytes) {
  const K = [0x428a2f98,0x71374491,0xb5c0fbcf,0xe9b5dba5,0x3956c25b,0x59f111f1,0x923f82a4,0xab1c5ed5,0xd807aa98,0x12835b01,0x243185be,0x550c7dc3,0x72be5d74,0x80deb1fe,0x9bdc06a7,0xc19bf174,0xe49b69c1,0xefbe4786,0x0fc19dc6,0x240ca1cc,0x2de92c6f,0x4a7484aa,0x5cb0a9dc,0x76f988da,0x983e5152,0xa831c66d,0xb00327c8,0xbf597fc7,0xc6e00bf3,0xd5a79147,0x06ca6351,0x14292967,0x27b70a85,0x2e1b2138,0x4d2c6dfc,0x53380d13,0x650a7354,0x766a0abb,0x81c2c92e,0x92722c85,0xa2bfe8a1,0xa81a664b,0xc24b8b70,0xc76c51a3,0xd192e819,0xd6990624,0xf40e3585,0x106aa070,0x19a4c116,0x1e376c08,0x2748774c,0x34b0bcb5,0x391c0cb3,0x4ed8aa4a,0x5b9cca4f,0x682e6ff3,0x748f82ee,0x78a5636f,0x84c87814,0x8cc70208,0x90befffa,0xa4506ceb,0xbef9a3f7,0xc67178f2];
  let h = [0x6a09e667,0xbb67ae85,0x3c6ef372,0xa54ff53a,0x510e527f,0x9b05688c,0x1f83d9ab,0x5be0cd19];
  const ml = msgBytes.length * 8;
  msgBytes.push(0x80);
  while (msgBytes.length % 64 !== 56) msgBytes.push(0);
  for (let i = 56; i >= 0; i -= 8) msgBytes.push((ml / Math.pow(2, i)) & 0xff);
  for (let i = 0; i < msgBytes.length; i += 64) {
    const w = [];
    for (let j = 0; j < 16; j++) w[j] = (msgBytes[i+j*4]<<24)|(msgBytes[i+j*4+1]<<16)|(msgBytes[i+j*4+2]<<8)|msgBytes[i+j*4+3];
    for (let j = 16; j < 64; j++) {
      const s0 = (w[j-15]>>>7|w[j-15]<<25)^(w[j-15]>>>18|w[j-15]<<14)^(w[j-15]>>>3);
      const s1 = (w[j-2]>>>17|w[j-2]<<15)^(w[j-2]>>>19|w[j-2]<<13)^(w[j-2]>>>10);
      w[j] = (w[j-16]+s0+w[j-7]+s1) >>> 0;
    }
    let [a,b,c,d,e,f,g,hh] = h;
    for (let j = 0; j < 64; j++) {
      const S1 = (e>>>6|e<<26)^(e>>>11|e<<21)^(e>>>25|e<<7);
      const ch = (e&f)^(~e&g);
      const t1 = (hh+S1+ch+K[j]+w[j]) >>> 0;
      const S0 = (a>>>2|a<<30)^(a>>>13|a<<19)^(a>>>22|a<<10);
      const maj = (a&b)^(a&c)^(b&c);
      const t2 = (S0+maj) >>> 0;
      hh=g; g=f; f=e; e=(d+t1)>>>0; d=c; c=b; b=a; a=(t1+t2)>>>0;
    }
    h = h.map((v,i)=>[a,b,c,d,e,f,g,hh][i]+v>>>0);
  }
  return h.map(v=>v.toString(16).padStart(8,'0')).join('');
}
function strToBytes(s) { return Array.from(s).map(c => c.charCodeAt(0) & 0xff); }
function hmacSha256(key, msg) {
  let k = strToBytes(key);
  const blockSize = 64;
  if (k.length > blockSize) { const h = sha256([...k]); k = h.match(/../g).map(x => parseInt(x,16)); }
  while (k.length < blockSize) k.push(0);
  const ipad = k.map(b => b ^ 0x36);
  const opad = k.map(b => b ^ 0x5c);
  const innerBytes = sha256([...ipad, ...strToBytes(msg)]).match(/../g).map(x => parseInt(x,16));
  return sha256([...opad, ...innerBytes]);
}

function roundStep(qty, decimals) {
  const factor = Math.pow(10, decimals);
  return Math.floor(qty * factor) / factor;
}

// Decision comes from Sign Balance URL node (passed through from Decision Engine)
const signNode = $('Sign Balance URL').first().json;
const decision = signNode.decision || {};
const action   = signNode.action || decision.action;
const trade    = { ...(signNode.trade || decision.trade || {}) };  // copy so we can mutate

// Helper: always return a valid output with full tradeContext so Process Order Fill can read symbol etc
function makeOutput(url, side, sym, qParam, qValue) {
  return [{ json: {
    url,
    headers: { 'X-MBX-APIKEY': API_KEY },
    orderSide: side, symbol: sym, quantityParam: qParam, quantityValue: qValue,
    action, tradeContext: trade,
    btcSignal:   decision.btcSignal   || null,
    portfolio:   decision.portfolio   || {},
    scanSummary: decision.scanSummary || []
  } }];
}

let side, symbol, quantityParam, quantityValue;

if (action === 'buy') {
  const sd = $getWorkflowStaticData('global');

  // Use real USDT balance from Fetch Real Balance — prevents oversized orders
  let realUSDT = 0;
  let balNode = null;
  try {
    balNode = $('Fetch Real Balance').first().json;
    const balances = (balNode.balances) || [];
    const usdtBal = balances.find(b => b.asset === 'USDT');
    realUSDT = usdtBal ? parseFloat(usdtBal.free || 0) : 0;
  } catch(e) { realUSDT = 0; }

  // If real USDT < 10, we may already be in a coin position (state lost but coins held on Binance)
  if (realUSDT < 10) {
    const allBalances = (balNode && balNode.balances) || [];
    const STABLES = new Set(['USDT','USDC','BUSD','TUSD','DAI','FDUSD','USDP','BNB']);
    const heldCoin = allBalances.find(b => !STABLES.has(b.asset) && parseFloat(b.free || 0) > 0);
    if (heldCoin) {
      // We're in a position — recover sd.position from real balance so TP/SL can manage it
      const coinSymbol = heldCoin.asset + 'USDT';
      const coinQty = parseFloat(heldCoin.free);
      let coinPrice = 0;
      try {
        const allItems = $('Fetch All Tickers').all();
        const tickers = allItems.length > 1 ? allItems.map(i => i.json) : (() => { const r = allItems[0].json; return Array.isArray(r) ? r : Object.values(r); })();
        const tk = tickers.find(t => t.symbol === coinSymbol);
        coinPrice = tk ? parseFloat(tk.lastPrice || 0) : 0;
      } catch(e) { coinPrice = 0; }
      if (!sd.position && coinPrice > 0 && coinQty * coinPrice > 5) {
        sd.position = { symbol: coinSymbol, entry: coinPrice, qty: coinQty, tradeValue: +(coinQty * coinPrice).toFixed(2), tpPct: 0.015, slPct: 0.01, highWater: coinPrice, entryTime: new Date().toISOString(), entryScore: 0 };
      }
      sd.pendingFill = null;
      return makeOutput('https://api.binance.com/api/v3/ping', 'BUY', 'SKIP', 'quoteOrderQty', '0');
    }
    // Genuinely no funds — alert via Telegram
    sd.pendingFill = null;
    const balDiag = 'realUSDT=' + realUSDT.toFixed(2) + ' | raw:' + JSON.stringify(balNode || {}).slice(0, 250);
    const out = makeOutput('https://api.binance.com/api/v3/ping', 'BUY', trade.symbol || 'SKIP', 'quoteOrderQty', '0');
    out[0].json.balanceFetchError = true;
    out[0].json.balanceFetchDiag = balDiag;
    return out;
  }

  // Use 98% of real free USDT, also sync sd.capital
  sd.capital = realUSDT;
  const tradeValue = +(realUSDT * 0.98).toFixed(2);

  side          = 'BUY';
  symbol        = trade.symbol;
  quantityParam = 'quoteOrderQty';
  quantityValue = tradeValue.toFixed(2);

  trade.tradeValue  = tradeValue;
  trade.realBalance = realUSDT;

} else if (action === 'close_tp' || action === 'close_sl' || action === 'close_switch') {
  const sd = $getWorkflowStaticData('global');
  symbol = trade.symbol || (sd.position && sd.position.symbol);

  // Use real coin balance from Fetch Real Balance — avoids -2010 from qty mismatch
  let realCoinQty = 0;
  try {
    const balNode  = $('Fetch Real Balance').first().json;
    const balances = balNode.balances || [];
    const base     = symbol.replace('USDT', '');
    const coinBal  = balances.find(b => b.asset === base);
    realCoinQty    = coinBal ? parseFloat(coinBal.free || 0) : 0;
  } catch(e) { realCoinQty = 0; }

  // Fall back to sd.position.qty if balance fetch failed
  if (realCoinQty <= 0) realCoinQty = sd.position ? sd.position.qty : (trade.qty || 0);

  // Get LOT_SIZE stepDecimals from Fetch Exchange Info node
  let stepDp = 2; // safe default
  try {
    const exInfo = $('Fetch Exchange Info').first().json;
    const lot = ((exInfo.symbols || [])[0]?.filters || []).find(f => f.filterType === 'LOT_SIZE');
    if (lot) {
      const step = lot.stepSize.replace(/0+$/, '');
      stepDp = step.includes('.') ? step.split('.')[1].length : 0;
    }
  } catch(e) { stepDp = 2; }
  const factor  = Math.pow(10, stepDp);
  side          = 'SELL';
  quantityParam = 'quantity';
  quantityValue = Math.floor(realCoinQty * factor) / factor + '';
} else {
  // Unknown action — release guard and pass through
  const sd = $getWorkflowStaticData('global');
  sd.pendingFill = null;
  return makeOutput('https://api.binance.com/api/v3/ping', 'BUY', trade.symbol || 'SKIP', 'quoteOrderQty', '0');
}

const timestamp   = Date.now();
const queryString = 'symbol=' + symbol + '&side=' + side + '&type=MARKET&' + quantityParam + '=' + quantityValue + '&recvWindow=5000&timestamp=' + timestamp;
const signature   = hmacSha256(SECRET_KEY, queryString);
const signedUrl   = 'https://api.binance.com' + ORDER_PATH + '?' + queryString + '&signature=' + signature;

return makeOutput(signedUrl, side, symbol, quantityParam, quantityValue);