let accounts = [];
let retainedEarnings = null;
let isLocked = false;

function formatNumber(n) {
  return Number(n || 0).toLocaleString();
}

function recalcTotals() {
  let debit = 0;
  let credit = 0;

  // 先算：不含繰越利益
  accounts.forEach((a) => {
    if (a.account_name === "繰越利益") return;
    debit += Number(a.opening_debit || 0);
    credit += Number(a.opening_credit || 0);
  });

  const diff = debit - credit;

  // 自动计算 繰越利益
  if (retainedEarnings) {
    if (diff > 0) {
      retainedEarnings.opening_debit = 0;
      retainedEarnings.opening_credit = diff;
    } else {
      retainedEarnings.opening_debit = -diff;
      retainedEarnings.opening_credit = 0;
    }
  }

  // 再算一次（包含繰越利益）
  let finalDebit = 0;
  let finalCredit = 0;

  accounts.forEach((a) => {
    finalDebit += Number(a.opening_debit || 0);
    finalCredit += Number(a.opening_credit || 0);
  });

  document.getElementById("totalDebit").innerText = formatNumber(finalDebit);
  document.getElementById("totalCredit").innerText = formatNumber(finalCredit);
  document.getElementById("diff").innerText = formatNumber(
    finalDebit - finalCredit
  );
}

async function loadOpeningBalances() {
  const year = document.getElementById("fiscalYear").value;

  const data = await apiGet("/opening-balances", { fiscal_year: year });

  accounts = data;
  retainedEarnings = accounts.find((a) => a.account_name === "繰越利益");

  const tbody = document.querySelector("#balanceTable tbody");
  tbody.innerHTML = "";

  GROUPS.forEach((group) => {
    // 分组标题行
    const headerTr = document.createElement("tr");
    headerTr.innerHTML = `
    <td colspan="4" style="background:#ddd; font-weight:bold;">
      ${group.label}
    </td>
  `;
    tbody.appendChild(headerTr);

    accounts.forEach((a, i) => {
      if (a.account_type !== group.key) return;

      const isRetained = a.account_name === "繰越利益";
      const tr = document.createElement("tr");

      tr.innerHTML = `
      <td>${a.account_code}</td>
      <td>${a.account_name}</td>
      <td>
        <input type="number" value="${a.opening_debit}"
          ${isRetained ? "readonly" : ""}
          onchange="accounts[${i}].opening_debit=this.value; recalcTotals();">
      </td>
      <td>
        <input type="number" value="${a.opening_credit}"
          ${isRetained ? "readonly" : ""}
          onchange="accounts[${i}].opening_credit=this.value; recalcTotals();">
      </td>
    `;

      tbody.appendChild(tr);
    });
  });

  // 年度锁定チェック
  fetch(
    `http://127.0.0.1:18080/opening-balances/lock-status?fiscal_year=${year}`
  )
    .then((res) => res.json())
    .then((data) => {
      isLocked = data.is_locked;
      document.querySelector(
        "button[onclick='saveOpeningBalances()']"
      ).disabled = isLocked;
      if (isLocked) {
        alert("この会計年度の期首残高は確定されています。");
      }
    });

  recalcTotals();
}

async function saveOpeningBalances() {
  if (isLocked) {
    alert("この会計年度の期首残高は確定されているため、保存できません。");
    return;
  }
  const year = Number(document.getElementById("fiscalYear").value);

  const balances = accounts
    // ❗ 排除 繰越利益
    .filter(
      (a) =>
        a.account_name !== "繰越利益" &&
        (Number(a.opening_debit) !== 0 || Number(a.opening_credit) !== 0)
    )
    .map((a) => ({
      account_id: a.account_id,
      debit: Number(a.opening_debit || 0),
      credit: Number(a.opening_credit || 0),
    }));

  try {
    await fetch("http://127.0.0.1:18080/opening-balances", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({
        fiscal_year: year,
        balances: balances,
      }),
    }).then(async (res) => {
      if (!res.ok) {
        const data = await res.json();
        throw new Error(data.detail);
      }
    });

    alert("期首残高を保存しました");
  } catch (e) {
    alert(e.message);
  }
}