// utils/timeline-template-processor.js

export const generateTimelineFromTemplate = (dimensions, template, mediaStoreData) => {
    const { selectedMeme, selectedBackground, currentCaption } = mediaStoreData;

    // If no selections, return empty timeline
    if (!selectedMeme && !selectedBackground) {
        return [];
    }

    // Calculate duration based on template config
    let maxDuration = 5; // default fallback
    if (template.max_duration_based_on === 'memes' && selectedMeme?.duration) {
        maxDuration = parseFloat(selectedMeme.duration);
    }

    // Process each timeline element
    const processedTimeline = template.timeline
        .map((element) => {
            let processedElement = { ...element };

            // Update duration for all elements
            processedElement.duration = maxDuration;

            // Process by element ID/type
            switch (element.id) {
                case 'background':
                    if (selectedBackground) {
                        processedElement.source = selectedBackground.media_url;
                        processedElement.name = selectedBackground.prompt || 'Background';
                        processedElement.media_width = selectedBackground.media_width;
                        processedElement.media_height = selectedBackground.media_height;

                        const canvasWidth = dimensions.width;
                        const canvasHeight = dimensions.height;

                        // Calculate scale factors to fit media within canvas while maintaining aspect ratio
                        const scaleX = canvasWidth / selectedBackground.media_width;
                        const scaleY = canvasHeight / selectedBackground.media_height;

                        // Use the larger scale factor to ensure the media fills the entire canvas
                        const scale = Math.max(scaleX, scaleY);

                        // Calculate final dimensions
                        const scaledWidth = selectedBackground.media_width * scale;
                        const scaledHeight = selectedBackground.media_height * scale;

                        // Center the scaled media within the canvas
                        const offsetX = (canvasWidth - scaledWidth) / 2;
                        const offsetY = (canvasHeight - scaledHeight) / 2;

                        // Set the processed element properties
                        processedElement.width = scaledWidth;
                        processedElement.height = scaledHeight;
                        processedElement.x = offsetX;
                        processedElement.y = offsetY;
                    } else {
                        return null; // Skip if no background selected
                    }
                    break;

                case 'meme':
                    if (selectedMeme) {
                        processedElement.source_webm = selectedMeme.webm_url;
                        processedElement.source_mov = selectedMeme.mov_url;
                        processedElement.poster = selectedMeme.webp_url;
                        processedElement.name = selectedMeme.name;
                        processedElement.media_width = selectedMeme.media_width;
                        processedElement.media_height = selectedMeme.media_height;
                        processedElement.width = selectedMeme.media_width;
                        processedElement.height = selectedMeme.media_height;
                    } else {
                        return null; // Skip if no meme selected
                    }
                    break;

                case 'caption':
                    if (currentCaption) {
                        processedElement.text = currentCaption;
                    } else {
                        return null; // Skip if no caption
                    }
                    break;

                default:
                    // Keep element as-is for any other types
                    break;
            }

            return processedElement;
        })
        .filter(Boolean); // Remove null elements

    return processedTimeline;
};