/**
 * OG Image Backend Module – live preview via AJAX
 * EXT:vitec/Resources/Public/Javascript/og-image-preview.js
 */
(function () {
    'use strict';

    /** Debounce helper */
    function debounce(fn, ms) {
        let t;
        return function (...args) {
            clearTimeout(t);
            t = setTimeout(() => fn.apply(this, args), ms);
        };
    }

    /** Collect all form values into a FormData-compatible plain object */
    function collectFormData() {
        const form = document.getElementById('vitecOgForm');
        if (!form) return {};
        const fd = new FormData(form);
        const out = {};
        for (const [key, val] of fd.entries()) {
            // key looks like "ogimage[something]"
            const match = key.match(/^ogimage\[(.+)]$/);
            if (match) {
                out[key] = val;
            }
        }
        return out;
    }

    /** POST to the preview endpoint, update the <img> */
    async function requestPreview() {
        const form = document.getElementById('vitecOgForm');
        const spinner = document.getElementById('previewSpinner');
        const img     = document.getElementById('ogPreviewImg');
        const placeholder = document.getElementById('ogPreviewPlaceholder');
        const dl      = document.getElementById('previewDownload');

        if (!form) return;

        if (spinner) spinner.classList.remove('d-none');

        try {
            const body = new URLSearchParams(collectFormData());
            const previewUrl = form.dataset.previewUrl || window.location.href;

            const resp = await fetch(previewUrl, {
                method: 'POST',
                headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
                body: body.toString(),
            });

            if (!resp.ok) throw new Error('Server error ' + resp.status);

            const json = await resp.json();

            if (json.success && json.dataUri) {
                img.src = json.dataUri;
                img.style.display = 'block';
                if (placeholder) placeholder.style.display = 'none';

                if (dl) {
                    dl.href = json.dataUri;
                    dl.classList.remove('d-none');
                }
            } else {
                console.warn('[OG Preview]', json.message);
            }
        } catch (e) {
            console.error('[OG Preview] fetch failed:', e);
        } finally {
            if (spinner) spinner.classList.add('d-none');
        }
    }

    const debouncedPreview = debounce(requestPreview, 600);

    // ── Wire up events once DOM is ready ──────────────────────────────

    document.addEventListener('DOMContentLoaded', function () {

        // Manual preview button
        const btn = document.getElementById('btnPreview');
        if (btn) {
            btn.addEventListener('click', requestPreview);
        }

        // Auto-preview on any .js-live input change
        document.querySelectorAll('.js-live').forEach(function (el) {
            el.addEventListener('input',  debouncedPreview);
            el.addEventListener('change', debouncedPreview);
        });

        // Background type toggle (show colour vs image picker)
        function syncBgType() {
            const colorWrap = document.getElementById('bg-color-wrap');
            const imageWrap = document.getElementById('bg-image-wrap');
            const selected  = document.querySelector('input.js-bg-type:checked');
            if (!selected) return;
            if (selected.value === 'image') {
                colorWrap && (colorWrap.style.display = 'none');
                imageWrap && (imageWrap.style.display = 'block');
            } else {
                colorWrap && (colorWrap.style.display = 'block');
                imageWrap && (imageWrap.style.display = 'none');
            }
        }

        document.querySelectorAll('input.js-bg-type').forEach(function (el) {
            el.addEventListener('change', function () {
                syncBgType();
                debouncedPreview();
            });
        });

        const bgImageSelect = document.querySelector('select[name="ogimage[bg_image]"]');
        if (bgImageSelect) {
            bgImageSelect.addEventListener('change', function () {
                const imageTypeRadio = document.querySelector('input.js-bg-type[value="image"]');
                if (imageTypeRadio) {
                    imageTypeRadio.checked = true;
                }
                syncBgType();
                requestPreview();
            });
        }

        syncBgType(); // initialise on load

        // Hex text ↔ colour picker sync
        document.querySelectorAll('.js-hex-sync').forEach(function (hexInput) {
            const targetId = hexInput.dataset.target;
            const picker   = document.getElementById(targetId);
            if (!picker) return;

            picker.addEventListener('input', function () {
                hexInput.value = picker.value;
            });

            hexInput.addEventListener('input', function () {
                const val = hexInput.value.trim();
                if (/^#[0-9a-fA-F]{6}$/.test(val)) {
                    picker.value = val;
                    picker.dispatchEvent(new Event('input', { bubbles: true }));
                }
            });
        });

        // Preset buttons
        document.querySelectorAll('.js-preset').forEach(function (btn) {
            btn.addEventListener('click', function () {
                const bg = btn.dataset.bg;
                const tc = btn.dataset.titleColor;
                const sc = btn.dataset.subtitleColor;

                const bgInput = document.getElementById('bgColor');
                if (bgInput && bg) { bgInput.value = bg; bgInput.dispatchEvent(new Event('input', {bubbles:true})); }

                const tInput = document.getElementById('titleColor');
                if (tInput && tc) { tInput.value = tc; tInput.dispatchEvent(new Event('input', {bubbles:true})); }

                const sInput = document.getElementById('subtitleColor');
                if (sInput && sc) { sInput.value = sc; sInput.dispatchEvent(new Event('input', {bubbles:true})); }

                debouncedPreview();
            });
        });

    });

})();