document.addEventListener('DOMContentLoaded', () => {
    // DOM Elements
    const uploadBtn = document.getElementById('upload-btn');
    const audioUpload = document.getElementById('audio-upload');
    const audioControls = document.getElementById('audio-controls');
    const songTitle = document.getElementById('song-title');
    const songDuration = document.getElementById('song-duration');
    const currentTimeEl = document.getElementById('current-time');
    const totalTimeEl = document.getElementById('total-time');
    const playBtn = document.getElementById('play-btn');
    const visualPreview = document.getElementById('visual-preview');
    const styleOptions = document.getElementById('style-options');
    const renderSection = document.getElementById('render-section');
    const generateBtn = document.getElementById('generate-btn');
    const progressContainer = document.getElementById('progress-container');
    const progressBar = document.getElementById('progress-bar');
    const progressPercent = document.getElementById('progress-percent');
    const downloadSection = document.getElementById('download-section');
    const downloadBtn = document.getElementById('download-btn');
    const visualizerCanvas = document.getElementById('visualizer');
    const videoCanvas = document.getElementById('video-canvas');
    
    // Audio context and variables
    let audioContext;
    let analyser;
    let audioBuffer;
    let audioElement;
    let wavesurfer;
    let isPlaying = false;
    let selectedStyle = 'abstract';
    let animationId;
    
    // Initialize Wavesurfer
    function initWavesurfer() {
        wavesurfer = WaveSurfer.create({
            container: '#waveform',
            waveColor: '#8B5CF6',
            progressColor: '#EC4899',
            cursorColor: '#EC4899',
            barWidth: 2,
            barRadius: 3,
            cursorWidth: 1,
            height: 60,
            barGap: 2,
            responsive: true,
        });
        
        wavesurfer.on('ready', () => {
            audioElement = wavesurfer.backend.getAudioElement();
            setupAudioAnalysis();
            updateDuration();
            playBtn.innerHTML = '<i data-feather="play" class="w-5 h-5"></i>';
            feather.replace();
        });
        
        wavesurfer.on('audioprocess', updateCurrentTime);
        wavesurfer.on('seek', updateCurrentTime);
        wavesurfer.on('finish', () => {
            isPlaying = false;
            playBtn.innerHTML = '<i data-feather="play" class="w-5 h-5"></i>';
            feather.replace();
        });
    }
    
    // Setup audio analysis
    function setupAudioAnalysis() {
        audioContext = new (window.AudioContext || window.webkitAudioContext)();
        analyser = audioContext.createAnalyser();
        analyser.fftSize = 256;
        
        const source = audioContext.createMediaElementSource(audioElement);
        source.connect(analyser);
        analyser.connect(audioContext.destination);
        
        startVisualizer();
    }
    
    // Audio visualizer
    function startVisualizer() {
        const canvasCtx = visualizerCanvas.getContext('2d');
        const WIDTH = visualizerCanvas.width = visualizerCanvas.offsetWidth;
        const HEIGHT = visualizerCanvas.height = visualizerCanvas.offsetHeight;
        
        const bufferLength = analyser.frequencyBinCount;
        const dataArray = new Uint8Array(bufferLength);
        
        function draw() {
            animationId = requestAnimationFrame(draw);
            
            analyser.getByteFrequencyData(dataArray);
            
            canvasCtx.fillStyle = 'rgba(0, 0, 0, 0.1)';
            canvasCtx.fillRect(0, 0, WIDTH, HEIGHT);
            
            const barWidth = (WIDTH / bufferLength) * 2.5;
            let x = 0;
            
            for (let i = 0; i < bufferLength; i++) {
                const barHeight = (dataArray[i] / 255) * HEIGHT;
                const hue = i / bufferLength * 360;
                
                canvasCtx.fillStyle = `hsla(${hue}, 100%, 50%, 0.8)`;
                canvasCtx.fillRect(x, HEIGHT - barHeight, barWidth, barHeight);
                
                x += barWidth + 1;
            }
        }
        
        draw();
    }
    
    // Update current time display
    function updateCurrentTime() {
        if (audioElement) {
            const currentTime = formatTime(audioElement.currentTime);
            currentTimeEl.textContent = currentTime;
        }
    }
    
    // Update duration display
    function updateDuration() {
        if (audioElement) {
            const duration = formatTime(audioElement.duration);
            totalTimeEl.textContent = duration;
            songDuration.textContent = duration;
        }
    }
    
    // Format time (seconds to MM:SS)
    function formatTime(seconds) {
        const mins = Math.floor(seconds / 60);
        const secs = Math.floor(seconds % 60);
        return `${mins}:${secs < 10 ? '0' : ''}${secs}`;
    }
    
    // Generate background image based on audio analysis
    function generateBackgroundImage(style) {
        // In a real app, this would use the audio analysis to generate an image
        // For demo purposes, we'll use placeholder gradients based on style
        
        let gradient;
        switch (style) {
            case 'nature':
                gradient = 'linear-gradient(135deg, #10B981 0%, #3B82F6 100%)';
                break;
            case 'cosmic':
                gradient = 'linear-gradient(135deg, #8B5CF6 0%, #EC4899 100%)';
                break;
            default: // abstract
                gradient = 'linear-gradient(135deg, #6366F1 0%, #A78BFA 50%, #F472B6 100%)';
        }
        
        visualPreview.style.backgroundImage = gradient;
    }
    
    // Event listeners
    uploadBtn.addEventListener('click', () => audioUpload.click());
    
    audioUpload.addEventListener('change', (e) => {
        const file = e.target.files[0];
        if (!file) return;
        
        songTitle.textContent = file.name.replace('.mp3', '');
        
        // Initialize wavesurfer if not already done
        if (!wavesurfer) {
            initWavesurfer();
        }
        
        const blobUrl = URL.createObjectURL(file);
        wavesurfer.load(blobUrl);
        
        audioControls.classList.remove('hidden');
        styleOptions.classList.remove('hidden');
        renderSection.classList.remove('hidden');
        downloadSection.classList.add('hidden');
        
        // Generate initial background
        generateBackgroundImage(selectedStyle);
    });
    
    playBtn.addEventListener('click', () => {
        if (!wavesurfer) return;
        
        if (isPlaying) {
            wavesurfer.pause();
            isPlaying = false;
            playBtn.innerHTML = '<i data-feather="play" class="w-5 h-5"></i>';
        } else {
            wavesurfer.play();
            isPlaying = true;
            playBtn.innerHTML = '<i data-feather="pause" class="w-5 h-5"></i>';
        }
        feather.replace();
    });
    
    // Style selection
    document.querySelectorAll('.style-option').forEach(btn => {
        btn.addEventListener('click', () => {
            selectedStyle = btn.dataset.style;
            document.querySelectorAll('.style-option').forEach(b => {
                b.classList.remove('border-purple-500', 'border-2');
            });
            btn.classList.add('border-purple-500', 'border-2');
            generateBackgroundImage(selectedStyle);
        });
    });
    // Generate video
    generateBtn.addEventListener('click', async () => {
        if (!wavesurfer || wavesurfer.isLoading()) {
            alert('Please wait for the audio to finish loading first');
            return;
        }

        // Reset visualizer if already running
        if (animationId) {
            cancelAnimationFrame(animationId);
        }

        generateBtn.disabled = true;
        generateBtn.innerHTML = '<span class="animate-pulse">Generating...</span>';
        progressContainer.classList.remove('hidden');
        
        // Setup video canvas
        videoCanvas.width = 1280;
        videoCanvas.height = 720;
        const videoCtx = videoCanvas.getContext('2d');
        videoCanvas.classList.remove('hidden');

        // Create a MediaRecorder to capture the visualization
        const stream = videoCanvas.captureStream(30);
        const mediaRecorder = new MediaRecorder(stream, {
            mimeType: 'video/webm;codecs=vp9'
        });

        const chunks = [];
        mediaRecorder.ondataavailable = (event) => {
            chunks.push(event.data);
        };

        mediaRecorder.onstop = () => {
            const blob = new Blob(chunks, { type: 'video/webm' });
            const url = URL.createObjectURL(blob);
            
            // Convert to MP4 (simulated)
            setTimeout(() => {
                progressBar.style.width = '100%';
                progressPercent.textContent = '100%';
                progressPercent.previousElementSibling.textContent = 'Finalizing...';
                
                setTimeout(() => {
                    generateBtn.disabled = false;
                    generateBtn.innerHTML = 'Generate Video';
                    progressContainer.classList.add('hidden');
                    downloadSection.classList.remove('hidden');
                    
                    downloadBtn.href = url;
                    downloadBtn.download = `${songTitle.textContent || 'audio-visualization'}.mp4`;
                }, 500);
            }, 1000);
        };

        // Start recording
        mediaRecorder.start(100); // Collect data every 100ms

        // Animation frame for video generation
        let startTime = Date.now();
        const duration = wavesurfer.getDuration() * 1000;
        let lastFrameTime = 0;
        const frameRate = 30;
        const frameInterval = 1000 / frameRate;

        function renderVideoFrame() {
            const currentTime = Date.now() - startTime;
            const progress = Math.min(100, (currentTime / duration) * 100);
            
            progressBar.style.width = `${progress}%`;
            progressPercent.textContent = `${Math.round(progress)}%`;
            progressPercent.previousElementSibling.textContent = 'Rendering...';

            // Update visualization
            const analyserData = new Uint8Array(analyser.frequencyBinCount);
            analyser.getByteFrequencyData(analyserData);

            // Draw visualization
            videoCtx.fillStyle = 'rgba(0, 0, 0, 1)';
            videoCtx.fillRect(0, 0, videoCanvas.width, videoCanvas.height);

            // Create gradient based on selected style
            let gradient;
            switch(selectedStyle) {
                case 'nature':
                    gradient = videoCtx.createLinearGradient(0, 0, videoCanvas.width, videoCanvas.height);
                    gradient.addColorStop(0, '#10B981');
                    gradient.addColorStop(1, '#3B82F6');
                    break;
                case 'cosmic':
                    gradient = videoCtx.createLinearGradient(0, 0, videoCanvas.width, videoCanvas.height);
                    gradient.addColorStop(0, '#8B5CF6');
                    gradient.addColorStop(1, '#EC4899');
                    break;
                default: // abstract
                    gradient = videoCtx.createLinearGradient(0, 0, videoCanvas.width, videoCanvas.height);
                    gradient.addColorStop(0, '#6366F1');
                    gradient.addColorStop(0.5, '#A78BFA');
                    gradient.addColorStop(1, '#F472B6');
            }

            // Draw bars based on audio data
            const barWidth = videoCanvas.width / analyserData.length;
            for (let i = 0; i < analyserData.length; i++) {
                const barHeight = (analyserData[i] / 255) * videoCanvas.height;
                videoCtx.fillStyle = gradient;
                videoCtx.fillRect(i * barWidth, videoCanvas.height - barHeight, barWidth, barHeight);
            }

            // Add song title
            videoCtx.fillStyle = 'white';
            videoCtx.font = 'bold 48px Poppins';
            videoCtx.textAlign = 'center';
            videoCtx.fillText(songTitle.textContent || 'Audio Visualization', videoCanvas.width/2, videoCanvas.height/2);

            if (currentTime < duration) {
                animationId = requestAnimationFrame(renderVideoFrame);
            } else {
                mediaRecorder.stop();
            }
        }

        // Start the visualization
        renderVideoFrame();
});
    // Clean up on unmount
    window.addEventListener('beforeunload', () => {
        if (animationId) {
            cancelAnimationFrame(animationId);
        }
        if (audioContext && audioContext.state !== 'closed') {
            audioContext.close();
        }
        // Clean up any media streams
        const streams = videoCanvas.captureStream().getTracks();
        streams.forEach(stream => stream.stop());
    });
});