# app.py
# =============
# This is a complete app.py file for a Gradio application that allows users to upload an audio file and generate a video with frequency visualization.

import gradio as gr
import numpy as np
import matplotlib.pyplot as plt
import librosa
import librosa.display
import os
import cv2

# Function to generate frequency visualization frames from audio
def generate_frequency_visualization(audio_path, fps, num_bars):
    try:
        # Load the audio file
        y, sr = librosa.load(audio_path, sr=None)
        duration = librosa.get_duration(y=y, sr=sr)
        print(f"Loaded audio file with sampling rate: {sr}, and duration: {duration} seconds.")

        if sr == 0 or len(y) == 0:
            raise ValueError("Invalid audio file: sampling rate or audio data is zero.")

        # Perform Short-Time Fourier Transform (STFT)
        hop_length = int(sr / fps)  # Hop length to match the desired fps
        S = np.abs(librosa.stft(y, n_fft=2048, hop_length=hop_length))
        frequencies = librosa.fft_frequencies(sr=sr)

        # Create frequency bins for the bars
        bins = np.linspace(0, len(frequencies), num_bars + 1, dtype=int)
        bar_heights = []

        # Aggregate power for each bar
        for i in range(len(S[0])):
            frame = S[:, i]
            bar_frame = [np.mean(frame[bins[j]:bins[j+1]]) for j in range(num_bars)]
            bar_heights.append(bar_frame)

        # Create a directory to save the frames
        os.makedirs('frames', exist_ok=True)

        # Generate and save each frame
        for i, heights in enumerate(bar_heights):
            fig, ax = plt.subplots(figsize=(10, 6))
            ax.bar(range(num_bars), heights, color=plt.cm.viridis(np.linspace(0, 1, num_bars)))
            ax.set_ylim(0, np.max(S))
            ax.axis('off')
            plt.savefig(f'frames/frame_{i:04d}.png', bbox_inches='tight', pad_inches=0)
            plt.close()

        print(f"Generated {len(bar_heights)} frames for visualization.")
        return 'frames', duration
    except Exception as e:
        print(f"Error generating frequency visualization: {e}")
        return None, None

# Function to create a video from the generated frames
def create_video_from_frames(frames_directory, audio_path, fps, duration):
    try:
        # Get the list of frame files
        frame_files = [os.path.join(frames_directory, f) for f in os.listdir(frames_directory) if f.endswith('.png')]
        frame_files.sort()

        if not frame_files:
            raise ValueError("No frames found to create the video.")

        # Get video dimensions from the first frame
        first_frame = cv2.imread(frame_files[0])
        height, width, _ = first_frame.shape

        # Initialize video writer
        video_path = 'output_video.mp4'
        fourcc = cv2.VideoWriter_fourcc(*'mp4v')
        video_writer = cv2.VideoWriter(video_path, fourcc, fps, (width, height))

        # Write frames to video
        for frame_file in frame_files:
            frame = cv2.imread(frame_file)
            video_writer.write(frame)

        video_writer.release()

        # Merge audio with video using ffmpeg
        os.system(f"ffmpeg -i {video_path} -i {audio_path} -c:v copy -c:a aac -strict experimental output_with_audio.mp4 -y")

        print(f"Video created with {len(frame_files)} frames.")
        return 'output_with_audio.mp4'
    except Exception as e:
        print(f"Error creating video from frames: {e}")
        return None

# Gradio interface function
def process_audio(audio):
    audio_path = audio
    fps = 60
    num_bars = 12
    frames_directory, duration = generate_frequency_visualization(audio_path, fps, num_bars)
    if frames_directory:
        video_path = create_video_from_frames(frames_directory, audio_path, fps, duration)
        return video_path
    else:
        return None

# Create the Gradio interface with explanations and recommendations
iface = gr.Interface(
    fn=process_audio,
    inputs=gr.Audio(type="filepath", label="Upload Audio File"),
    outputs=gr.Video(label="Generated Video"),
    title="Audio Frequency Visualization",
    description="Upload an audio file to generate a video with frequency visualization. "
                "Supported file types: WAV, MP3, FLAC. "
                "Recommended file duration: 10 seconds to 5 minutes. "
                "The visualization will consist of 12 bars representing frequency ranges.",
)

# Launch the Gradio interface
if __name__ == "__main__":
    iface.launch()

# Dependencies
# =============
# The following dependencies are required to run this app:
# - librosa
# - numpy
# - matplotlib
# - opencv-python
# - ffmpeg (installed separately)