const transferSaveButton = document.querySelector("[data-transfer-save]");
const transferBroadcastButton = document.querySelector("[data-transfer-broadcast]");
const ATOMIC_UNITS_PER_COIN = 100000000n;
const NON_BASE_TRANSFER_MIN_FEE_ATOMIC = 100000000n;
let transferBalancesRefreshPromise = null;

function setTransferMessage(message, type = "") {
  setScopedTransactionMessage("Transfer", transferMessage, message, type);
}

function balanceAtomicValue(balance) {
  try {
    return BigInt(balance?.balance || "0");
  } catch (_) {
    return 0n;
  }
}

function transferAssetKey(balance) {
  return `${balance?.asset || ""}|${Number(balance?.nft_series || 0)}`;
}

function transferAssetLabel(balance) {
  const amount = formatAtomicBalance(balance?.balance || "0");
  const series = Number(balance?.nft_series || 0);
  if (series > 0) {
    return `${balance.asset} #${series} (${amount})`;
  }
  return `${balance.asset} (${amount})`;
}

function decimalToAtomic(value) {
  const text = String(value || "").trim();
  if (!/^\d+(\.\d{0,8})?$/.test(text)) {
    return null;
  }

  const [whole, fraction = ""] = text.split(".");
  const paddedFraction = fraction.padEnd(8, "0");
  return BigInt(whole || "0") * ATOMIC_UNITS_PER_COIN + BigInt(paddedFraction || "0");
}

function atomicToDecimal(value) {
  const atomic = BigInt(value || 0);
  const whole = atomic / ATOMIC_UNITS_PER_COIN;
  const fraction = String(atomic % ATOMIC_UNITS_PER_COIN).padStart(8, "0");
  return `${whole}.${fraction}`;
}

function isBaseTransferAsset(asset) {
  return String(asset || "").trim().toUpperCase() === activeBaseCoin();
}

function minimumTransferFee(amount, asset) {
  if (isBaseTransferAsset(asset)) {
    return (amount + 99n) / 100n;
  }
  return NON_BASE_TRANSFER_MIN_FEE_ATOMIC;
}

function baseCoinBalanceAtomic() {
  const baseCoin = activeBaseCoin();
  const baseBalance = (Array.isArray(activeWalletBalances) ? activeWalletBalances : []).find((balance) => {
    return String(balance.asset || "").trim().toUpperCase() === baseCoin && !Number(balance.nft_series || 0);
  });
  return balanceAtomicValue(baseBalance);
}

function selectedTransferAsset() {
  if (!transferAssetSelect?.value) {
    return null;
  }

  const option = transferAssetSelect.selectedOptions?.[0];
  if (!option) {
    return null;
  }

  return {
    asset: option.dataset.asset || "",
    nftSeries: Number(option.dataset.nftSeries || 0),
    balance: BigInt(option.dataset.balance || "0")
  };
}

function updateTransferDerivedFields() {
  const selected = selectedTransferAsset();
  const sender = activeWalletAddressShort || activeWalletAddressHex || "--";

  if (transferSender) {
    transferSender.textContent = sender;
  }

  if (!selected) {
    if (transferCoin) {
      transferCoin.textContent = "--";
    }
    if (transferNftSeries) {
      transferNftSeries.textContent = "0";
    }
    if (transferBalance) {
      transferBalance.textContent = "--";
    }
    if (transferAmountInput) {
      transferAmountInput.disabled = false;
    }
    if (transferFeeInput) {
      transferFeeInput.value = "";
    }
    return;
  }

  if (transferCoin) {
    transferCoin.textContent = selected.asset || "--";
  }
  if (transferNftSeries) {
    transferNftSeries.textContent = String(selected.nftSeries || 0);
  }
  if (transferBalance) {
    const seriesLabel = selected.nftSeries > 0 ? ` #${selected.nftSeries}` : "";
    transferBalance.textContent = `${formatAtomicBalance(String(selected.balance))} ${selected.asset}${seriesLabel}`;
  }

  if (transferAmountInput) {
    if (selected.nftSeries > 0) {
      transferAmountInput.value = "1";
      transferAmountInput.disabled = true;
    } else {
      transferAmountInput.disabled = false;
    }
  }

  updateTransferFee();
}

function updateTransferFee() {
  if (!transferFeeInput) {
    return;
  }

  const selected = selectedTransferAsset();
  if (!selected) {
    transferFeeInput.value = "";
    return;
  }

  const amount = selected.nftSeries > 0 ? 1n : decimalToAtomic(transferAmountInput?.value);
  if (amount === null || amount <= 0n) {
    transferFeeInput.value = "";
    return;
  }

  transferFeeInput.value = atomicToDecimal(minimumTransferFee(amount, selected.asset));
}

function refreshTransferAssetOptions() {
  if (!transferAssetSelect) {
    return;
  }

  const previous = transferAssetSelect.value;
  transferAssetSelect.innerHTML = "";

  const spendableBalances = (Array.isArray(activeWalletBalances) ? activeWalletBalances : [])
    .filter((balance) => (balance.asset || "").trim() && balanceAtomicValue(balance) > 0n)
    .sort((left, right) => {
      const leftSeries = Number(left.nft_series || 0);
      const rightSeries = Number(right.nft_series || 0);
      if ((left.asset || "") !== (right.asset || "")) {
        return (left.asset || "").localeCompare(right.asset || "");
      }
      return leftSeries - rightSeries;
    });

  if (!spendableBalances.length) {
    const option = document.createElement("option");
    option.value = "";
    option.textContent = walletLoaded ? "No spendable assets found" : "Load a wallet first";
    transferAssetSelect.appendChild(option);
    updateTransferDerivedFields();
    return;
  }

  spendableBalances.forEach((balance) => {
    const option = document.createElement("option");
    option.value = transferAssetKey(balance);
    option.textContent = transferAssetLabel(balance);
    option.dataset.asset = balance.asset || "";
    option.dataset.nftSeries = String(Number(balance.nft_series || 0));
    option.dataset.balance = String(balance.balance || "0");
    transferAssetSelect.appendChild(option);
  });

  if ([...transferAssetSelect.options].some((option) => option.value === previous)) {
    transferAssetSelect.value = previous;
  }

  updateTransferDerivedFields();
}

async function refreshTransferBalancesIfNeeded() {
  if (activeWalletBalances.length || !walletLoaded || !registrationRegistered) {
    refreshTransferAssetOptions();
    return;
  }

  if (transferBalancesRefreshPromise) {
    return transferBalancesRefreshPromise;
  }

  const invoke = window.__TAURI__?.core?.invoke;
  const broadcastNode = activeBroadcastNode();
  if (!invoke || !broadcastNode) {
    refreshTransferAssetOptions();
    return;
  }

  transferBalancesRefreshPromise = (async () => {
    setTransferMessage("Loading spendable assets...");
    try {
      const balances = await invoke("get_active_wallet_balances", { broadcastNode });
      activeWalletBalances = Array.isArray(balances) ? balances : [];
      refreshTransferAssetOptions();
      setTransferMessage("");
    } catch (error) {
      refreshTransferAssetOptions();
      setTransferMessage(String(error), "error");
      throw error;
    } finally {
      transferBalancesRefreshPromise = null;
    }
  })();

  return transferBalancesRefreshPromise;
}

function parseTransferPaymentUri(value) {
  const text = String(value || "").trim();
  let uri;
  try {
    uri = new URL(text);
  } catch (_) {
    throw new Error("Enter a valid Contractless payment URI.");
  }

  if (uri.protocol.toLowerCase() !== "contractless:") {
    throw new Error("Payment URI must begin with contractless:.");
  }

  const encodedAddress = uri.hostname || uri.pathname.replace(/^\/+/, "");
  let receiver;
  try {
    receiver = decodeURIComponent(encodedAddress).trim();
  } catch (_) {
    throw new Error("Payment URI contains an invalid receiver address.");
  }
  if (!receiver) {
    throw new Error("Payment URI does not contain a receiver address.");
  }

  const asset = (uri.searchParams.get("asset") || activeBaseCoin()).trim();
  if (!asset) {
    throw new Error("Payment URI does not contain a valid asset.");
  }

  const amount = (uri.searchParams.get("amount") || "").trim();
  if (amount) {
    const atomicAmount = decimalToAtomic(amount);
    if (atomicAmount === null || atomicAmount <= 0n) {
      throw new Error("Payment URI contains an invalid amount.");
    }
  }

  const label = (uri.searchParams.get("label") || "").trim();

  return { receiver, asset, amount, label };
}

async function loadTransferPaymentUri(value) {
  const payment = parseTransferPaymentUri(value);
  openTransactionType("Transfer");
  await refreshTransferBalancesIfNeeded();

  const matchingOption = [...(transferAssetSelect?.options || [])].find((option) => {
    return (
      String(option.dataset.asset || "").trim().toLowerCase() === payment.asset.toLowerCase() &&
      Number(option.dataset.nftSeries || 0) === 0
    );
  });

  if (!matchingOption) {
    throw new Error(`The active wallet does not have a spendable ${payment.asset} balance.`);
  }

  transferAssetSelect.value = matchingOption.value;
  transferReceiverInput.value = payment.receiver;
  transferAmountInput.value = payment.amount;
  if (typeof addPaymentUriAddressBookEntry === "function") {
    await addPaymentUriAddressBookEntry(payment.receiver, payment.label);
  }
  updateTransferDerivedFields();
  updateTransferFee();
  setTransferMessage("");
}

function validateTransferForm() {
  const selected = selectedTransferAsset();
  if (!walletLoaded) {
    return "Load a wallet before creating a transfer.";
  }
  if (!registrationRegistered) {
    return "Address registration is required before creating a transfer.";
  }
  if (!selected) {
    return "Select a coin, token, or NFT to transfer.";
  }

  const receiver = String(transferReceiverInput?.value || "").trim();
  if (!receiver) {
    return "Enter a receiver address.";
  }
  if (
    receiver.toLowerCase() === String(activeWalletAddressHex || "").toLowerCase() ||
    receiver.toLowerCase() === String(activeWalletAddressShort || "").toLowerCase()
  ) {
    return "Receiver cannot be the active wallet address.";
  }

  const amount = selected.nftSeries > 0 ? 1n : decimalToAtomic(transferAmountInput?.value);
  if (amount === null || amount <= 0n) {
    return "Enter a valid amount with up to 8 decimal places.";
  }
  if (selected.nftSeries > 0 && String(transferAmountInput?.value || "").trim() !== "1") {
    return "NFT transfers must send exactly 1 item.";
  }
  if (amount > selected.balance) {
    return "Amount exceeds the available balance for this asset.";
  }

  const expectedFee = minimumTransferFee(amount, selected.asset);
  const fee = decimalToAtomic(transferFeeInput?.value || "0");
  if (fee === null) {
    return "Transaction fee could not be calculated.";
  }
  if (fee < expectedFee) {
    return `Transaction fee must be at least ${atomicToDecimal(expectedFee)} ${activeBaseCoin()}.`;
  }

  const baseBalance = baseCoinBalanceAtomic();
  if (isBaseTransferAsset(selected.asset)) {
    if (amount + fee > selected.balance) {
      return "Amount plus transaction fee exceeds the available base coin balance.";
    }
  } else if (fee > baseBalance) {
    return `This transfer needs ${atomicToDecimal(fee)} ${activeBaseCoin()} for the transaction fee.`;
  }

  return "";
}

function transferPayload() {
  const selected = selectedTransferAsset();
  const value = selected?.nftSeries > 0 ? 1n : decimalToAtomic(transferAmountInput?.value);
  const fee = decimalToAtomic(transferFeeInput?.value || "0");

  return {
    receiver: String(transferReceiverInput?.value || "").trim(),
    coin: selected?.asset || "",
    nftSeries: Number(selected?.nftSeries || 0),
    value: String(value || 0n),
    txfee: String(fee || 0n)
  };
}

function setTransferButtonsDisabled(disabled) {
  if (transferSaveButton) {
    transferSaveButton.disabled = disabled;
  }
  if (transferBroadcastButton) {
    transferBroadcastButton.disabled = disabled;
  }
}

function clearTransferForm() {
  if (transferReceiverInput) {
    transferReceiverInput.value = "";
  }
  if (transferAmountInput) {
    transferAmountInput.value = "";
  }
  if (transferAssetSelect) {
    transferAssetSelect.selectedIndex = -1;
  }
  updateTransferDerivedFields();
}

async function handleTransferAction(action) {
  const error = validateTransferForm();
  if (error) {
    setTransferMessage(error, "error");
    return;
  }

  const invoke = window.__TAURI__?.core?.invoke;
  if (!invoke) {
    setTransferMessage("Wallet bridge is not available.", "error");
    return;
  }

  const walletKey = await requestSigningWalletKey();
  if (guiRuntimeSettings.require_key_before_signing !== false && !walletKey) {
    setTransferMessage("Signing cancelled.");
    return;
  }

  setTransferButtonsDisabled(true);
  try {
    if (action === "save") {
      const broadcastNode = activeBroadcastNode();
      if (!broadcastNode) {
        throw new Error("Select a broadcast node before saving.");
      }
      setTransferMessage("Saving transfer...");
      const review = await invoke("save_transfer_transaction", {
        ...transferPayload(),
        broadcastNode,
        walletKey
      });
      clearTransferForm();
      setTransferMessage(`Transfer saved to unbroadcast transactions: ${review.file_name}`, "success");
      if (typeof refreshUnbroadcastTransactions === "function") {
        refreshUnbroadcastTransactions();
      }
    } else {
      const broadcastNode = activeBroadcastNode();
      if (!broadcastNode) {
        throw new Error("Select a broadcast node before broadcasting.");
      }
      setTransferMessage("Broadcasting transfer...");
      const result = await invoke("broadcast_transfer_transaction", {
        ...transferPayload(),
        broadcastNode,
        walletKey
      });
      clearTransferForm();
      setTransferMessage(result.response || "Transfer broadcast.", "success");
    }
  } catch (error) {
    setTransferMessage(String(error), "error");
  } finally {
    setTransferButtonsDisabled(false);
  }
}

function prepareTransferForm() {
  setTransferMessage("");
  refreshTransferBalancesIfNeeded().catch(() => {
    // The form already displays the RPC error; keep navigation responsive.
  });
}

transferAssetSelect?.addEventListener("change", () => {
  updateTransferDerivedFields();
  setTransferMessage("");
});
transferReceiverInput?.addEventListener("input", () => setTransferMessage(""));
transferAmountInput?.addEventListener("input", () => {
  updateTransferFee();
  setTransferMessage("");
});
transferSaveButton?.addEventListener("click", () => handleTransferAction("save"));
transferBroadcastButton?.addEventListener("click", () => handleTransferAction("broadcast"));

topbarPaymentUriInput?.addEventListener("input", () => {
  topbarPaymentUriInput.setCustomValidity("");
});

topbarPaymentUriForm?.addEventListener("submit", async (event) => {
  event.preventDefault();
  topbarPaymentUriInput?.setCustomValidity("");

  try {
    await loadTransferPaymentUri(topbarPaymentUriInput?.value);
    if (topbarPaymentUriInput) {
      topbarPaymentUriInput.value = "";
    }
  } catch (error) {
    const message = error instanceof Error ? error.message : String(error);
    if (topbarPaymentUriInput) {
      topbarPaymentUriInput.setCustomValidity(message);
      topbarPaymentUriInput.reportValidity();
    }
    if (currentView === "send") {
      setTransferMessage(message, "error");
    }
  }
});