webapp/app.js

window.onload = function () {
    const tg = window.Telegram?.WebApp;
    if (!tg) {
        console.warn('Not in Telegram Web App');
        return;
    }

    // Payment Slip Form
    document.getElementById('slip-form').addEventListener('submit', async (e) => {
        e.preventDefault();
        const formData = new FormData(e.target);
        const file = formData.get('slip_image');

        const reader = new FileReader();
        reader.onload = () => {
            const base64 = reader.result.split(',')[1];
            tg.sendData(JSON.stringify({
                type: "payment_slip",
                booking_id: formData.get('booking_id'),
                reference: formData.get('reference') || "",
                file_base64: base64,
                file_name: file.name
            }));
            tg.close();
        };
        reader.readAsDataURL(file);
    });

    // Expense Form
    document.getElementById('expense-form').addEventListener('submit', (e) => {
        e.preventDefault();
        const data = new FormData(e.target);
        tg.sendData(JSON.stringify({
            type: "expense_entry",
            amount: data.get('amount'),
            category: data.get('category') || "อื่นๆ",
            note: data.get('note') || ""
        }));
        tg.close();
    });
};