let receiveTokenListRequestId = 0;

function setPaymentMessage(message, mode = "") {
  if (!paymentMessage) {
    return;
  }
  paymentMessage.textContent = message;
  paymentMessage.classList.toggle("error", mode === "error");
  paymentMessage.classList.toggle("success", mode === "success");
}

function receiveAddress() {
  return activeWalletAddressShort || activeWalletAddressHex || "";
}

function paymentRequestUri() {
  const address = receiveAddress();
  if (!address) {
    return "";
  }

  const params = new URLSearchParams();
  const asset = paymentAssetSelect?.value || activeBaseCoin();
  const amount = paymentAmountInput?.value?.trim() || "";
  const label = paymentLabelInput?.value?.trim() || "";

  if (asset) {
    params.set("asset", asset);
  }
  if (amount) {
    params.set("amount", amount);
  }
  if (label) {
    params.set("label", label);
  }

  const query = params.toString();
  return `contractless:${address}${query ? `?${query}` : ""}`;
}

function qrGaloisTables() {
  const exp = new Array(512).fill(0);
  const log = new Array(256).fill(0);
  let value = 1;
  for (let index = 0; index < 255; index += 1) {
    exp[index] = value;
    log[value] = index;
    value <<= 1;
    if (value & 0x100) {
      value ^= 0x11d;
    }
  }
  for (let index = 255; index < 512; index += 1) {
    exp[index] = exp[index - 255];
  }
  return { exp, log };
}

function qrMultiply(left, right, tables) {
  if (!left || !right) {
    return 0;
  }
  return tables.exp[tables.log[left] + tables.log[right]];
}

function qrGeneratorPolynomial(degree, tables) {
  let poly = [1];
  for (let index = 0; index < degree; index += 1) {
    const next = new Array(poly.length + 1).fill(0);
    poly.forEach((coefficient, coefficientIndex) => {
      next[coefficientIndex] ^= coefficient;
      next[coefficientIndex + 1] ^= qrMultiply(coefficient, tables.exp[index], tables);
    });
    poly = next;
  }
  return poly;
}

function qrReedSolomon(data, eccLength) {
  const tables = qrGaloisTables();
  const generator = qrGeneratorPolynomial(eccLength, tables);
  const ecc = new Array(eccLength).fill(0);

  data.forEach((byte) => {
    const factor = byte ^ ecc.shift();
    ecc.push(0);
    for (let index = 0; index < eccLength; index += 1) {
      ecc[index] ^= qrMultiply(generator[index + 1], factor, tables);
    }
  });
  return ecc;
}

function qrAppendBits(bits, value, length) {
  for (let bit = length - 1; bit >= 0; bit -= 1) {
    bits.push((value >>> bit) & 1);
  }
}

function qrEncodeBytes(text) {
  const bytes = Array.from(new TextEncoder().encode(text));
  if (bytes.length > 134) {
    throw new Error("Payment URI is too long for the QR code. Shorten the label or amount.");
  }

  const bits = [];
  qrAppendBits(bits, 0b0100, 4);
  qrAppendBits(bits, bytes.length, 8);
  bytes.forEach((byte) => qrAppendBits(bits, byte, 8));
  const dataBitCapacity = 136 * 8;
  const terminator = Math.min(4, dataBitCapacity - bits.length);
  qrAppendBits(bits, 0, terminator);
  while (bits.length % 8) {
    bits.push(0);
  }

  const data = [];
  for (let index = 0; index < bits.length; index += 8) {
    data.push(bits.slice(index, index + 8).reduce((value, bit) => (value << 1) | bit, 0));
  }
  for (let pad = 0xec; data.length < 136; pad = pad === 0xec ? 0x11 : 0xec) {
    data.push(pad);
  }

  const block1 = data.slice(0, 68);
  const block2 = data.slice(68, 136);
  const ecc1 = qrReedSolomon(block1, 18);
  const ecc2 = qrReedSolomon(block2, 18);
  const codewords = [];
  for (let index = 0; index < 68; index += 1) {
    codewords.push(block1[index], block2[index]);
  }
  for (let index = 0; index < 18; index += 1) {
    codewords.push(ecc1[index], ecc2[index]);
  }
  return codewords.flatMap((byte) => {
    const out = [];
    qrAppendBits(out, byte, 8);
    return out;
  });
}

function qrFormatBits() {
  let data = 0b01000; // ECC level L, mask 0.
  let value = data << 10;
  const generator = 0x537;
  for (let bit = 14; bit >= 10; bit -= 1) {
    if ((value >>> bit) & 1) {
      value ^= generator << (bit - 10);
    }
  }
  return ((data << 10) | value) ^ 0x5412;
}

function qrSet(matrix, reserved, row, col, value, isReserved = true) {
  if (row < 0 || col < 0 || row >= matrix.length || col >= matrix.length) {
    return;
  }
  matrix[row][col] = Boolean(value);
  if (isReserved) {
    reserved[row][col] = true;
  }
}

function qrFinder(matrix, reserved, row, col) {
  for (let y = -1; y <= 7; y += 1) {
    for (let x = -1; x <= 7; x += 1) {
      const r = row + y;
      const c = col + x;
      const dark = x >= 0 && x <= 6 && y >= 0 && y <= 6
        && (x === 0 || x === 6 || y === 0 || y === 6 || (x >= 2 && x <= 4 && y >= 2 && y <= 4));
      qrSet(matrix, reserved, r, c, dark);
    }
  }
}

function qrAlignment(matrix, reserved, row, col) {
  for (let y = -2; y <= 2; y += 1) {
    for (let x = -2; x <= 2; x += 1) {
      qrSet(matrix, reserved, row + y, col + x, Math.max(Math.abs(x), Math.abs(y)) !== 1);
    }
  }
}

function qrBuildMatrix(text) {
  const size = 41;
  const matrix = Array.from({ length: size }, () => new Array(size).fill(false));
  const reserved = Array.from({ length: size }, () => new Array(size).fill(false));

  qrFinder(matrix, reserved, 0, 0);
  qrFinder(matrix, reserved, 0, size - 7);
  qrFinder(matrix, reserved, size - 7, 0);
  qrAlignment(matrix, reserved, 34, 34);

  for (let index = 8; index < size - 8; index += 1) {
    qrSet(matrix, reserved, 6, index, index % 2 === 0);
    qrSet(matrix, reserved, index, 6, index % 2 === 0);
  }
  qrSet(matrix, reserved, 33, 8, true);

  for (let index = 0; index < 9; index += 1) {
    if (index !== 6) {
      reserved[8][index] = true;
      reserved[index][8] = true;
    }
  }
  for (let index = 0; index < 8; index += 1) {
    reserved[8][size - 1 - index] = true;
    reserved[size - 1 - index][8] = true;
  }

  const bits = qrEncodeBytes(text);
  let bitIndex = 0;
  let upward = true;
  for (let col = size - 1; col > 0; col -= 2) {
    if (col === 6) {
      col -= 1;
    }
    for (let step = 0; step < size; step += 1) {
      const row = upward ? size - 1 - step : step;
      for (let offset = 0; offset < 2; offset += 1) {
        const c = col - offset;
        if (reserved[row][c]) {
          continue;
        }
        const dark = bitIndex < bits.length ? bits[bitIndex] === 1 : false;
        matrix[row][c] = ((row + c) % 2 === 0) ? !dark : dark;
        bitIndex += 1;
      }
    }
    upward = !upward;
  }

  const format = qrFormatBits();
  for (let index = 0; index < 15; index += 1) {
    const bit = ((format >>> index) & 1) === 1;
    const first = [
      [8, 0], [8, 1], [8, 2], [8, 3], [8, 4], [8, 5], [8, 7], [8, 8],
      [7, 8], [5, 8], [4, 8], [3, 8], [2, 8], [1, 8], [0, 8]
    ][index];
    const second = index < 8 ? [size - 1 - index, 8] : [8, size - 15 + index];
    qrSet(matrix, reserved, first[0], first[1], bit);
    qrSet(matrix, reserved, second[0], second[1], bit);
  }

  return matrix;
}

function drawPaymentQr(canvas, text, label) {
  if (!canvas) {
    return;
  }

  const size = canvas.width || 256;
  const context = canvas.getContext("2d");
  if (!context) {
    return;
  }

  context.fillStyle = "#ffffff";
  context.fillRect(0, 0, size, size);
  context.fillStyle = "#101820";

  try {
    const matrix = qrBuildMatrix(text);
    const modules = matrix.length;
    const quiet = 4;
    const cell = Math.floor(size / (modules + quiet * 2));
    const offset = Math.floor((size - cell * modules) / 2);
    matrix.forEach((row, y) => {
      row.forEach((dark, x) => {
        if (dark) {
          context.fillRect(offset + x * cell, offset + y * cell, cell, cell);
        }
      });
    });
    setPaymentMessage("");
  } catch (error) {
    context.fillStyle = "#101820";
    context.font = "16px sans-serif";
    context.textAlign = "center";
    context.fillText("QR unavailable", size / 2, size / 2 - 8);
    context.font = "12px sans-serif";
    context.fillText("Shorten request text", size / 2, size / 2 + 14);
    setPaymentMessage(String(error), "error");
  }

  if (label) {
    const footerHeight = 28;
    context.fillStyle = "rgba(255,255,255,0.92)";
    context.fillRect(0, size - footerHeight, size, footerHeight);
    context.fillStyle = "#101820";
    context.font = "13px sans-serif";
    context.textAlign = "center";
    const trimmed = label.length > 30 ? `${label.slice(0, 27)}...` : label;
    context.fillText(trimmed, size / 2, size - 10);
  }
}

function drawEmptyPaymentQr(canvas) {
  if (!canvas) {
    return;
  }
  const size = canvas.width || 256;
  const context = canvas.getContext("2d");
  if (!context) {
    return;
  }
  context.fillStyle = "#ffffff";
  context.fillRect(0, 0, size, size);
  context.fillStyle = "#101820";
  context.font = "16px sans-serif";
  context.textAlign = "center";
  context.fillText("Load wallet", size / 2, size / 2);
}

function renderPaymentQr(uri, label) {
  if (!uri) {
    drawEmptyPaymentQr(paymentQrCanvas);
    return;
  }
  drawPaymentQr(paymentQrCanvas, uri, label);
}

function updateReceiveDetails() {
  if (receiveRegistration) {
    receiveRegistration.textContent = registrationRegistered ? "Registered" : "Unregistered";
  }
}

function updatePaymentRequest() {
  const uri = paymentRequestUri();
  if (paymentUriInput) {
    paymentUriInput.value = uri;
  }
  if (paymentQrLabel) {
    paymentQrLabel.textContent = paymentLabelInput?.value?.trim() || "Payment Request";
  }
  renderPaymentQr(uri, paymentQrLabel?.textContent || "");
  updateReceiveDetails();
}

async function refreshReceiveTokenList() {
  const invoke = window.__TAURI__?.core?.invoke;
  const broadcastNode = activeBroadcastNode();
  if (!invoke || !walletLoaded || !broadcastNode || !paymentAssetSelect) {
    return;
  }

  const requestId = ++receiveTokenListRequestId;
  const selected = paymentAssetSelect.value || activeBaseCoin();
  paymentAssetSelect.innerHTML = "";
  const baseOption = document.createElement("option");
  baseOption.value = activeBaseCoin();
  baseOption.textContent = activeBaseCoin();
  paymentAssetSelect.appendChild(baseOption);

  try {
    const tokens = await invokeWalletRpcWithBackoff(
      "Token list lookup",
      () => invoke("token_list", { broadcastNode }),
      () => requestId === receiveTokenListRequestId && walletLoaded
    );
    if (requestId !== receiveTokenListRequestId || !walletLoaded) {
      return;
    }

    (Array.isArray(tokens) ? tokens : []).forEach((token) => {
      const ticker = String(token?.ticker || "").trim();
      if (!ticker || ticker.toLowerCase() === activeBaseCoin().toLowerCase()) {
        return;
      }
      const option = document.createElement("option");
      option.value = ticker;
      option.textContent = ticker;
      paymentAssetSelect.appendChild(option);
    });
    paymentAssetSelect.value = [...paymentAssetSelect.options].some((option) => option.value === selected)
      ? selected
      : activeBaseCoin();
  } catch (error) {
    setPaymentMessage(String(error), "error");
  } finally {
    updatePaymentRequest();
  }
}

async function copyPaymentUri() {
  const uri = paymentRequestUri();
  if (!uri || !(await writeClipboardText(uri))) {
    setPaymentMessage("Payment URI is not available to copy.", "error");
    return;
  }
  setPaymentMessage("Payment URI copied.", "success");
}

async function copyPaymentQr() {
  if (!paymentQrCanvas || !navigator.clipboard || typeof ClipboardItem === "undefined") {
    await copyPaymentUri();
    return;
  }

  paymentQrCanvas.toBlob(async (blob) => {
    if (!blob) {
      setPaymentMessage("Payment QR is not available to copy.", "error");
      return;
    }
    try {
      await navigator.clipboard.write([
        new ClipboardItem({
          [blob.type]: blob
        })
      ]);
      setPaymentMessage("Payment request QR copied.", "success");
    } catch (_) {
      await copyPaymentUri();
    }
  }, "image/png");
}

function refreshReceivePage() {
  updateReceiveDetails();
  updatePaymentRequest();
  refreshReceiveTokenList();
}

[paymentAssetSelect, paymentAmountInput, paymentLabelInput].forEach((input) => {
  input?.addEventListener("input", updatePaymentRequest);
  input?.addEventListener("change", updatePaymentRequest);
});

copyPaymentUriButton?.addEventListener("click", copyPaymentUri);
copyPaymentQrButton?.addEventListener("click", copyPaymentQr);