let card;
let stripe;
const cardMessages = document.getElementById("card-messages");
const payButton = document.getElementById("pay-button");
const processing = document.getElementById("processing-payment");

// FIXME: not working in this way
stripe = Stripe('{{index .StringMap "publishable_key"}}');

function hidePayButton() {
    payButton.classList.add("d-none");
    processing.classList.remove("d-none");
}

function showPayButton() {
    payButton.classList.remove("d-none");
    processing.classList.add("d-none");
}

function showCardError(msg) {
    cardMessages.classList.add("alert-danger");
    cardMessages.classList.remove("alert-success");
    cardMessages.classList.remove("d-none");
    cardMessages.innerText = msg;
}

function showCardSuccess() {
    cardMessages.classList.add("alert-success");
    cardMessages.classList.remove("alert-danger");
    cardMessages.classList.remove("d-none");
    cardMessages.innerText = "Trasaction successful";
}

function val() {
    let form = document.getElementById("charge_form");

    if (form.checkValidity() === false) {
        this.event.preventDefault();
        this.event.stopPropagation();
        form.classList.add("was-validated");
        return;
    }
    form.classList.add("was-validated");
    hidePayButton();

    let amountToCharge = String(parseFloat(document.getElementById("amount").value) * 100);
    let payload = {
        amount: amountToCharge,
        currency: 'eur',
    };

    const requestOptions = {
        method: 'post',
        headers: {
            'Accept': 'application/json',
            'Content-Type': 'application/json',
        },
        body: JSON.stringify(payload),
    };

    fetch("{{index .API}}/api/payment-intent", requestOptions)
    .then(response => response.text())
        .then(response => {
            let data;
            try {
                data = JSON.parse(response);
                stripe.confirmCardPayment(data.client_secret, {
                    payment_method: {
                        card: card,
                        billing_details: {
                            name: document.getElementById("cardholder-name").value,
                        }
                    }
                }).then(function(result) {
                        if (result.error) {
                            // card declined, or sth went wrong with the card
                            showCardError(result.error.message);
                            showPayButton();
                        } else if (result.paymentIntent) {
                            if (result.paymentIntent.status === "succeeded") {
                                // we have charged the card
                                document.getElementById("payment_intent").value = result.paymentIntent.id;
                                document.getElementById("payment_method").value = result.paymentIntent.payment_method_types[0];
                                document.getElementById("payment_amount").value = result.paymentIntent.amount;
                                document.getElementById("payment_currency").value = result.paymentIntent.currency;
                                processing.classList.add("d-none");
                                showCardSuccess();
                                document.getElementById("charge_form").submit();
                            }
                        }
                    })
                console.log(data);

            } catch (err) {
                console.log(err);
                showCardError("Invalid response from payment gateway!");
                showPayButton();
            }
        });
}

(function () {
    // create stripe & elements
    const elements = stripe.elements();
    const style = {
        base: {
            fontSize: '16px',
            lineHeight: '24px',
        }
    };

    // create card entry
    card = elements.create('card', {
        style:style,
        hidePostalCode: true,
    });
    card.mount("#card-element");

    // check for input errors
    card.addEventListener('change', function(event) {
        var displayError = document.getElementById("card-errors");
        if (event.error) {
            displayError.classList.remove('d-none');
            displayError.textContent = event.error.message;
        } else {
            displayError.classList.add('d-none');
            displayError.textContent = "";
        }
    });
})();