document.addEventListener('DOMContentLoaded', function () {
    // UI Elements
    const sceneListEl = document.querySelector('.scene-list');
    const previewPanel = document.getElementById('preview-panel');
    const programPanel = document.getElementById('program-panel');
    const previewContent = previewPanel.querySelector('.scene-content');
    const programContent = programPanel.querySelector('.scene-content');
    const cutButton = document.getElementById('cut-button');
    
    // Modal Elements
    const addSceneBtn = document.getElementById('add-scene-btn');
    const modal = document.getElementById('add-scene-modal');
    const modalCloseBtn = document.getElementById('modal-close-btn');
    const modalCancelBtn = document.getElementById('modal-cancel-btn');
    const modalSaveBtn = document.getElementById('modal-save-btn');
    const sceneNameInput = document.getElementById('scene-name-input');
    const sceneTypeSelect = document.getElementById('scene-type-select');
    const sceneColorInput = document.getElementById('scene-color-input');

    // Data Store
    let scenes = [];
    let activePreviewSceneId = null;
    let activeProgramSceneId = null;
    let sceneIdCounter = 0;

    // --- DATA MANAGEMENT ---
    function addScene(name, type, value) {
        const newScene = {
            id: sceneIdCounter++,
            name: name,
            type: type,
            value: value
        };
        scenes.push(newScene);
        renderSceneList();
        return newScene;
    }

    function removeScene(id) {
        scenes = scenes.filter(scene => scene.id !== id);
        if (activePreviewSceneId === id) {
            clearPreview();
        }
        renderSceneList();
    }

    function getScene(id) {
        return scenes.find(scene => scene.id === id);
    }

    // --- UI RENDERING ---
    function renderSceneList() {
        sceneListEl.innerHTML = ''; // Clear existing list
        scenes.forEach(scene => {
            const icon = getIconForSceneType(scene.type);
            const item = document.createElement('div');
            item.className = 'list-group-item list-group-item-action';
            item.dataset.sceneId = scene.id;
            if (scene.id === activePreviewSceneId) {
                item.classList.add('active');
            }
            item.innerHTML = `
                <span class="scene-name">${icon} ${scene.name}</span>
                <button class="btn-close btn-close-white remove-scene-btn" aria-label="Remove"></button>
            `;
            sceneListEl.appendChild(item);
        });
    }

    function updatePreview(sceneId) {
        const scene = getScene(sceneId);
        if (!scene) return;

        activePreviewSceneId = scene.id;

        previewContent.textContent = scene.name;
        switch (scene.type) {
            case 'color':
                previewPanel.style.backgroundColor = scene.value;
                break;
            default:
                previewPanel.style.backgroundColor = '#000';
                break;
        }
        renderSceneList(); // Re-render to show active state
    }
    
    function clearPreview() {
        activePreviewSceneId = null;
        previewContent.textContent = 'Select a Scene';
        previewPanel.style.backgroundColor = '#000';
        renderSceneList();
    }

    function getIconForSceneType(type) {
        switch (type) {
            case 'color': return '<i class="bi bi-palette-fill"></i>';
            case 'image': return '<i class="bi bi-image-fill"></i>';
            case 'video': return '<i class="bi bi-film"></i>';
            default: return '<i class="bi bi-question-circle-fill"></i>';
        }
    }

    // --- EVENT LISTENERS ---

    // Scene list interactions (select, remove)
    sceneListEl.addEventListener('click', (e) => {
        const target = e.target;
        const sceneItem = target.closest('.list-group-item');
        if (!sceneItem) return;

        const sceneId = parseInt(sceneItem.dataset.sceneId);

        if (target.classList.contains('remove-scene-btn')) {
            removeScene(sceneId);
        } else {
            updatePreview(sceneId);
        }
    });

    // Transition button
    cutButton.addEventListener('click', () => {
        if (activePreviewSceneId === null) return;

        const previewScene = getScene(activePreviewSceneId);
        activeProgramSceneId = previewScene.id;

        programContent.textContent = previewScene.name;
        programPanel.style.backgroundColor = previewPanel.style.backgroundColor;
        
        clearPreview();
    });

    // Modal interactions
    function showModal() { modal.style.display = 'flex'; sceneNameInput.focus(); }
    function hideModal() { modal.style.display = 'none'; }

    addSceneBtn.addEventListener('click', showModal);
    modalCloseBtn.addEventListener('click', hideModal);
    modalCancelBtn.addEventListener('click', hideModal);

    modalSaveBtn.addEventListener('click', () => {
        const name = sceneNameInput.value.trim();
        if (!name) {
            alert('Please enter a scene name.');
            return;
        }
        const type = sceneTypeSelect.value;
        const value = sceneColorInput.value; // For now, only color

        const newScene = addScene(name, type, value);
        updatePreview(newScene.id);

        // Reset form and hide modal
        sceneNameInput.value = '';
        sceneColorInput.value = '#1e90ff';
        hideModal();
    });

    // --- INITIALIZATION ---
    function initialize() {
        // Add some default scenes
        addScene('Main Camera', 'color', '#003366');
        addScene('Screen Share', 'color', '#006633');
        addScene('Starting Soon', 'color', '#333333');

        // Set initial program scene for display
        const firstScene = scenes[0];
        if (firstScene) {
            activeProgramSceneId = firstScene.id;
            programContent.textContent = firstScene.name;
            programPanel.style.backgroundColor = firstScene.value;
        }
        
        // Select the second scene for preview initially
        if (scenes.length > 1) {
            updatePreview(scenes[1].id);
        }
    }

    initialize();
});