app.py

import gradio as gr
import pretty_midi
import numpy as np
import tempfile
import os
import scipy
from scipy import signal
import librosa
import io
import base64
from pathlib import Path

class HumanizeBot:
    def __init__(self):
        self.groove_profiles = {
            "drums": {"timing_var": 0.02, "velocity_var": 15, "swing_factor": 0.1},
            "melody": {"timing_var": 0.01, "velocity_var": 10, "swing_factor": 0.05},
            "bass": {"timing_var": 0.015, "velocity_var": 12, "swing_factor": 0.07},
            "chords": {"timing_var": 0.008, "velocity_var": 8, "swing_factor": 0.03},
            "other": {"timing_var": 0.01, "velocity_var": 10, "swing_factor": 0.05}
        }
    
    def classify_instrument(self, instrument):
        """Classify instrument type for appropriate humanization"""
        if instrument.is_drum:
            return "drums"
        elif 32 <= instrument.program <= 39:  # Bass
            return "bass"
        elif 0 <= instrument.program <= 7:  # Piano
            return "chords"
        elif 40 <= instrument.program <= 55:  # Strings, orchestra
            return "chords"
        elif 80 <= instrument.program <= 104:  # Synth leads, pads
            return "melody"
        else:
            return "melody"
    
    def apply_swing(self, notes, swing_factor, tempo):
        """Apply swing/groove to notes"""
        swung_notes = []
        for note in notes:
            # Simple swing: push even 8th notes slightly later
            beat_position = (note.start * tempo / 60) % 1
            if 0.25 < beat_position < 0.75:  # Off-beat positions
                note.start += 0.01 * swing_factor
                note.end += 0.01 * swing_factor
            swung_notes.append(note)
        return swung_notes
    
    def humanize_midi(self, midi_file, intensity=0.7, style="organic", add_swing=True):
        """Main humanization function"""
        try:
            # Load MIDI file
            midi_data = pretty_midi.PrettyMIDI(midi_file.name)
            tempo = midi_data.estimate_tempo()
            
            # Process each instrument
            for instrument in midi_data.instruments:
                inst_type = self.classify_instrument(instrument)
                profile = self.groove_profiles[inst_type]
                
                # Apply swing if requested
                if add_swing and inst_type in ["drums", "bass"]:
                    instrument.notes = self.apply_swing(
                        instrument.notes, 
                        profile["swing_factor"] * intensity, 
                        tempo
                    )
                
                # Humanize timing and velocity
                for note in instrument.notes:
                    # Humanize timing (more variation for drums)
                    timing_shift = np.random.normal(0, profile["timing_var"] * intensity)
                    note.start = max(0, note.start + timing_shift)
                    
                    # Humanize note duration (except for drums)
                    if not instrument.is_drum:
                        duration_shift = np.random.normal(0, profile["timing_var"] * 0.5 * intensity)
                        note.end = max(note.start + 0.05, note.end + duration_shift)
                    
                    # Humanize velocity
                    vel_pattern = self.get_velocity_pattern(note, instrument, style)
                    vel_shift = np.random.randint(-profile["velocity_var"], profile["velocity_var"])
                    new_velocity = note.velocity + int(vel_shift * intensity * vel_pattern)
                    note.velocity = max(20, min(127, new_velocity))
            
            # Save humanized MIDI
            output_path = tempfile.mktemp(suffix='_humanized.mid')
            midi_data.write(output_path)
            return output_path, "✅ Humanization successful! File is ready for download."
            
        except Exception as e:
            return None, f"❌ Error processing file: {str(e)}"
    
    def get_velocity_pattern(self, note, instrument, style):
        """Get velocity multiplier based on style and musical context"""
        if style == "organic":
            return 1.0
        elif style == "groovy":
            # Accentuate beats more
            beat_position = (note.start * 2) % 1  # Simple beat detection
            if beat_position < 0.1:  # On strong beats
                return 1.2
            else:
                return 0.9
        elif style == "gentle":
            return 0.8
        return 1.0

def create_audio_preview(midi_path):
    """Create a simple audio preview from MIDI"""
    try:
        midi_data = pretty_midi.PrettyMIDI(midi_path)
        # Generate audio using fluidsynth (simplified)
        audio_data = midi_data.synthesize()
        return 44100, audio_data.astype(np.float32)
    except:
        return None, None

def process_files(files, intensity, style, add_swing):
    if not files:
        return None, None, "Please upload MIDI files to begin."
    
    bot = HumanizeBot()
    processed_files = []
    audio_previews = []
    
    for file in files:
        humanized_path, message = bot.humanize_midi(file, intensity, style, add_swing)
        if humanized_path:
            processed_files.append(humanized_path)
            
            # Create audio preview
            sr, audio = create_audio_preview(humanized_path)
            if audio is not None:
                audio_previews.append((sr, audio))
    
    if processed_files:
        return processed_files, audio_previews[0] if audio_previews else None, f"✅ Successfully processed {len(processed_files)} files!"
    else:
        return None, None, "❌ No files were processed successfully."

# Create the Gradio interface
with gr.Blocks(theme=gr.themes.Soft(), title="HumanizeBot") as demo:
    gr.Markdown("""
    # 🎵 HumanizeBot
    **Remove AI traces from your music and make it sound human-made!**
    
    Upload MIDI files from AI music generators to apply natural humanization: subtle timing variations, velocity changes, and musical feel.
    """)
    
    with gr.Row():
        with gr.Column(scale=1):
            gr.Markdown("### 📁 Upload & Settings")
            
            file_input = gr.File(
                file_count="multiple",
                file_types=[".mid", ".midi"],
                label="Upload MIDI Files",
                type="filepath"
            )
            
            intensity = gr.Slider(
                0.1, 1.0, 
                value=0.7, 
                label="🎚️ Humanization Intensity",
                info="Low = subtle, High = very human"
            )
            
            style = gr.Radio(
                ["organic", "groovy", "gentle"], 
                value="organic", 
                label="🎸 Humanization Style",
                info="Organic = natural, Groovy = rhythmic, Gentle = subtle"
            )
            
            add_swing = gr.Checkbox(
                value=True,
                label="🔄 Add Swing/Groove",
                info="Add rhythmic push and pull"
            )
            
            process_btn = gr.Button(
                "✨ Humanize My Music!",
                variant="primary",
                size="lg"
            )
        
        with gr.Column(scale=1):
            gr.Markdown("### 📥 Download Results")
            
            file_output = gr.File(
                file_count="multiple",
                label="Download Humanized MIDI Files"
            )
            
            audio_output = gr.Audio(
                label="Audio Preview (First File)",
                interactive=False
            )
            
            status = gr.Textbox(
                label="Status",
                interactive=False,
                max_lines=3
            )
    
    # Examples section
    with gr.Accordion("🎯 Examples & Tips", open=False):
        gr.Markdown("""
        **Best used with:**
        - AI-generated MIDI from Soundraw, AIVA, MuseNet, etc.
        - Robotic-sounding drum patterns
        - Static piano or synth sequences
        
        **How it works:**
        - Adds subtle timing variations (like a human player)
        - Adjusts velocity (note strength) dynamically
        - Can add swing/groove for rhythmic parts
        - Preserves the original musical content
        
        **Pro tip:** Start with intensity 0.7 for balanced results!
        """)
    
    # Connect the processing function
    process_btn.click(
        fn=process_files,
        inputs=[file_input, intensity, style, add_swing],
        outputs=[file_output, audio_output, status]
    )
    
    gr.Markdown("""
    ---
    *Built with ❤️ using Gradio and PrettyMIDI. Works best with MIDI files from AI music generators.*
    """)

if __name__ == "__main__":
    demo.launch(debug=True)