let smsModalInstance = null;

function normalizeSmsNumber(number) {
    const raw = String(number || '').trim();
    if (!raw) return '';
    let cleaned = raw.replace(/[^\d+]/g, '');
    if (cleaned.startsWith('+')) cleaned = cleaned.slice(1);
    if (cleaned.startsWith('00')) cleaned = cleaned.slice(2);
    if (/^\d{8}$/.test(cleaned)) cleaned = `45${cleaned}`;
    return cleaned;
}

async function sendSms(number, message, sender = null, contactId = null) {
    const to = normalizeSmsNumber(number);
    if (!to) {
        alert('Ugyldigt mobilnummer');
        return { ok: false };
    }

    const response = await fetch('/api/v1/sms/send', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        credentials: 'include',
        body: JSON.stringify({ to, message, sender: sender || null, contact_id: contactId || null })
    });

    if (!response.ok) {
        const text = await response.text();
        alert('SMS fejlede: ' + text);
        return { ok: false };
    }

    const data = await response.json();
    alert('SMS sendt ✅');
    return { ok: true, data };
}

function updateSmsCounter() {
    const textarea = document.getElementById('smsMessageInput');
    const counter = document.getElementById('smsCharCounter');
    if (!textarea || !counter) return;
    const len = String(textarea.value || '').length;
    counter.textContent = `${len}/1530`;
    counter.classList.toggle('text-danger', len > 1530);
}

function ensureSmsModal() {
    const modalEl = document.getElementById('smsModal');
    if (!modalEl || !window.bootstrap) return null;
    if (!smsModalInstance) {
        smsModalInstance = new bootstrap.Modal(modalEl);
    }
    return smsModalInstance;
}

async function submitSmsFromModal() {
    const recipientInput = document.getElementById('smsRecipientInput');
    const senderInput = document.getElementById('smsSenderInput');
    const messageInput = document.getElementById('smsMessageInput');
    const sendBtn = document.getElementById('smsSendBtn');
    if (!recipientInput || !messageInput || !sendBtn) return;

    const recipient = String(recipientInput.value || '').trim();
    const message = String(messageInput.value || '').trim();
    const sender = String(senderInput?.value || '').trim();
    const contactIdRaw = String(recipientInput.dataset.contactId || '').trim();
    const contactId = contactIdRaw ? Number(contactIdRaw) : null;

    if (!recipient) {
        alert('Modtager mangler');
        return;
    }
    if (!message) {
        alert('Besked må ikke være tom');
        return;
    }
    if (message.length > 1530) {
        alert('Besked er for lang (max 1530 tegn)');
        return;
    }

    const original = sendBtn.innerHTML;
    sendBtn.disabled = true;
    sendBtn.innerHTML = '<span class="spinner-border spinner-border-sm me-2"></span>Sender...';

    try {
        const result = await sendSms(recipient, message, sender || null, contactId);
        if (result.ok) {
            const modal = ensureSmsModal();
            if (modal) modal.hide();
            messageInput.value = '';
            updateSmsCounter();
        }
    } finally {
        sendBtn.disabled = false;
        sendBtn.innerHTML = original;
    }
}

async function openSmsPrompt(number, label = '', contactId = null) {
    const recipient = String(number || '').trim();
    if (!recipient || recipient === '-') {
        alert('Intet gyldigt mobilnummer');
        return;
    }

    const modal = ensureSmsModal();
    const recipientInput = document.getElementById('smsRecipientInput');
    const title = document.getElementById('smsModalTitle');
    const messageInput = document.getElementById('smsMessageInput');
    if (modal && recipientInput && title && messageInput) {
        recipientInput.value = recipient;
        recipientInput.dataset.contactId = contactId ? String(contactId) : '';
        title.textContent = label ? `Send SMS til ${label}` : 'Send SMS';
        if (!messageInput.value) {
            messageInput.value = '';
        }
        updateSmsCounter();
        modal.show();
        setTimeout(() => messageInput.focus(), 200);
        return;
    }

    const fallbackPrefix = label ? `SMS til ${label} (${recipient})` : `SMS til ${recipient}`;
    const fallbackMessage = window.prompt(`${fallbackPrefix}\n\nSkriv besked:`);
    if (fallbackMessage === null) return;
    if (!String(fallbackMessage).trim()) {
        alert('Besked må ikke være tom');
        return;
    }

    try {
        await sendSms(recipient, String(fallbackMessage), null, contactId);
    } catch (error) {
        console.error('SMS send failed:', error);
        alert('Kunne ikke sende SMS');
    }
}

document.addEventListener('DOMContentLoaded', () => {
    const messageInput = document.getElementById('smsMessageInput');
    const sendBtn = document.getElementById('smsSendBtn');
    if (messageInput) {
        messageInput.addEventListener('input', updateSmsCounter);
        updateSmsCounter();
    }
    if (sendBtn) {
        sendBtn.addEventListener('click', submitSmsFromModal);
    }
});