// =======================
// Load members into accounting dropdown
// =======================
async function loadMembersForAccounting() {
  try {
    const res = await fetch('/api/members');
    if (!res.ok) throw new Error('Failed to fetch members');
    
    const members = await res.json();
    const select = document.getElementById('memberSelect');
    select.innerHTML = '<option value="">Select Member</option>';
    
    members.forEach(m => {
      const opt = document.createElement('option');
      opt.value = m.id;
      opt.textContent = `${m.name} (#${m.id})`;
      select.appendChild(opt);
    });
  } catch (error) {
    console.error(error);
  }
}

// =======================
// Show/hide payerName input based on payer type
// =======================
document.getElementById('payerType').addEventListener('change', (e) => {
  const isNonMember = e.target.value === 'non-member';
  document.getElementById('payerName').style.display = isNonMember ? 'inline-block' : 'none';
});

// =======================
// Load transactions and apply filters
// =======================
async function loadTransactions() {
  try {
    const res = await fetch('/api/accounting');
    if (!res.ok) throw new Error('Failed to fetch transactions');
    
    let transactions = await res.json();

    // Apply filters (assumes filters object exists with start/end properties)
    if (filters?.start || filters?.end) {
      transactions = transactions.filter(tx => {
        const txDate = new Date(tx.month + "-01");
        const start = filters.start ? new Date(filters.start + "-01") : null;
        const end = filters.end ? new Date(filters.end + "-01") : null;
        return (!start || txDate >= start) && (!end || txDate <= end);
      });
    }

    const tbody = document.getElementById('accountingBody');
tbody.innerHTML = transactions.map((t, i) => `
  <tr class="${t.category === 'expense' ? 'expense' : 'income'}">
    <td>${i + 1}</td>
    <td>${t.payerType === 'member' ? t.memberId : t.payerName}</td>
    <td>${t.payerType}</td>
    <td>${t.month}</td>
    <td>${t.amount}</td>
    <td>${t.category}</td>
    <td>${t.description || ''}</td>
    <td>
      <button class="btn btn-sm btn-primary" onclick="openActionModal(${t.id})">Actions</button>
    </td>
  </tr>
`).join('');

    // Update summary and charts with the filtered transactions
    updateAccountingSummary(transactions);
    renderMonthlyChart(transactions);
    renderIncomeExpenseChart(transactions);

  } catch (error) {
    console.error(error);
  }
}

// =======================
// Update accounting summary table
// =======================
async function updateAccountingSummary(transactionsParam = null) {
  try {
    const transactions = transactionsParam || await (await fetch('/api/accounting')).json();

    const summary = {
      contribution: 0,
      donation: 0,
      sale: 0,
      expense: 0,
      memberIncome: 0,
      nonMemberIncome: 0
    };

    transactions.forEach(tx => {
      if (tx.category === 'contribution') summary.contribution += tx.amount;
      else if (tx.category === 'donation') summary.donation += tx.amount;
      else if (tx.category === 'sale') summary.sale += tx.amount;
      else if (tx.category === 'expense') summary.expense += tx.amount;

      if (tx.payerType === 'member' && tx.category !== 'expense') summary.memberIncome += tx.amount;
      if (tx.payerType === 'non-member' && tx.category !== 'expense') summary.nonMemberIncome += tx.amount;
    });

    const tbody = document.getElementById('summaryBody');
    tbody.innerHTML = `
      <tr class="income-summary"><td>Contribution (Income)</td><td>${summary.contribution}</td></tr>
      <tr class="income-summary"><td>Donation (Income)</td><td>${summary.donation}</td></tr>
      <tr class="income-summary"><td>Sales (Income)</td><td>${summary.sale}</td></tr>
      <tr class="income-summary"><td>Total Income from Members</td><td>${summary.memberIncome}</td></tr>
      <tr class="income-summary"><td>Total Income from Non-Members</td><td>${summary.nonMemberIncome}</td></tr>
      <tr class="expense-summary"><td>Total Expenses</td><td>${summary.expense}</td></tr>
      <tr class="income-summary"><td>Net Total</td><td>${(summary.contribution + summary.donation + summary.sale) - summary.expense}</td></tr>
    `;
  } catch (error) {
    console.error(error);
  }
}

// =======================
// Handle transaction form submission
// =======================
document.getElementById('transactionForm').addEventListener('submit', async (e) => {
  e.preventDefault();

  const category = document.getElementById('transactionCategory').value;

  const transaction = {
    payerType: document.getElementById('payerType').value,
    memberId: document.getElementById('memberSelect').value || null,
    payerName: document.getElementById('payerName').value || null,
    month: document.getElementById('transactionMonth').value,
    amount: parseFloat(document.getElementById('transactionAmount').value),
    category,
    type: category === 'expense' ? 'expense' : 'income', // additional field for convenience
    description: document.getElementById('transactionDesc').value.trim()
  };

  try {
    const res = await fetch('/api/accounting', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify(transaction)
    });

    if (!res.ok) throw new Error('Failed to add transaction');

    document.getElementById('transactionForm').reset();
    loadTransactions();
    updateAccountingSummary();
    renderMonthlyChart();

  } catch (error) {
    console.error(error);
    alert('Failed to save transaction');
  }
});

// =======================
// Export accounting data as JSON
// =======================
document.getElementById('exportAccounting').addEventListener('click', () => {
  window.location.href = '/api/accounting/export';
});

// =======================
// Initial data load
// =======================
loadMembersForAccounting();
loadTransactions();
updateAccountingSummary();



let selectedTransaction = null;

// Open modal and load transaction data
window.openActionModal = async function (id) {
  const res = await fetch('/api/accounting');
  const transactions = await res.json();
  selectedTransaction = transactions.find(t => t.id === id);
  if (!selectedTransaction) return alert('Transaction not found');

  // Fill the form
  document.getElementById('editTransactionId').value = selectedTransaction.id;
  document.getElementById('editTransactionMonth').value = selectedTransaction.month;
  document.getElementById('editTransactionAmount').value = selectedTransaction.amount;
  document.getElementById('editTransactionCategory').value = selectedTransaction.category;
  document.getElementById('editTransactionDesc').value = selectedTransaction.description || '';

  // Show modal
  document.getElementById('transactionModal').classList.remove('hidden');
};

window.closeModal = function () {
  document.getElementById('transactionModal').classList.add('hidden');
  selectedTransaction = null;
};

// Save edited transaction
document.getElementById('editTransactionForm').addEventListener('submit', async function (e) {
  e.preventDefault();
  const id = document.getElementById('editTransactionId').value;

  const updatedTx = {
    ...selectedTransaction,
    month: document.getElementById('editTransactionMonth').value,
    amount: parseFloat(document.getElementById('editTransactionAmount').value),
    category: document.getElementById('editTransactionCategory').value,
    description: document.getElementById('editTransactionDesc').value
  };

  const res = await fetch(`/api/accounting/${id}`, {
    method: 'PUT',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify(updatedTx)
  });

  if (!res.ok) {
    alert('Failed to update transaction');
    return;
  }

  closeModal();
  loadTransactions();
});

// Delete transaction
window.deleteTransaction = async function () {
  const id = document.getElementById('editTransactionId').value;

  if (!confirm('Are you sure you want to delete this transaction?')) return;

  const res = await fetch(`/api/accounting/${id}`, {
    method: 'DELETE'
  });

  if (!res.ok) {
    alert('Failed to delete transaction');
    return;
  }

  closeModal();
  loadTransactions();
};