app.py

import random
import gradio as gr
import numpy as np
from midi_model import MIDIModel, MIDIModelConfig
from midi_synthesizer import MidiSynthesizer
import MIDI
import base64
import io
from huggingface_hub import hf_hub_download

MAX_SEED = np.iinfo(np.int32).max

class MIDIManager:
    def __init__(self):
        self.soundfont_path = hf_hub_download(repo_id="skytnt/midi-model", filename="soundfont.sf2")
        self.synthesizer = MidiSynthesizer(self.soundfont_path)
        self.loaded_midi = {}  # Store multiple MIDI files
        self.modified_files = []  # Track generated files for download
        self.is_playing = False

    def load_midi(self, file_path):
        midi = MIDI.load(file_path)
        midi_id = f"midi_{len(self.loaded_midi)}"
        self.loaded_midi[midi_id] = midi
        return midi_id, self.extract_notes_and_instruments(midi)

    def extract_notes_and_instruments(self, midi):
        notes = []
        instruments = set()
        for track in midi.tracks:
            for event in track.events:
                if event.type == 'note_on' and event.velocity > 0:
                    notes.append((event.note, event.velocity, event.time))
                if hasattr(event, 'program'):
                    instruments.add(event.program)
        return notes, list(instruments)

    def generate_variation(self, midi_id, length_factor=2, variation_level=0.3):
        if midi_id not in self.loaded_midi:
            return None
        original = self.loaded_midi[midi_id]
        notes, instruments = self.extract_notes_and_instruments(original)
        
        # Generate longer sequence
        new_notes = []
        for _ in range(int(length_factor)):
            for note, vel, time in notes:
                if random.random() < variation_level:
                    new_note = note + random.randint(-2, 2)
                    new_vel = min(127, max(0, vel + random.randint(-10, 10)))
                    new_notes.append((new_note, new_vel, time))
                else:
                    new_notes.append((note, vel, time))

        new_midi = MIDI.MIDIFile(1)
        new_midi.addTrack()
        for note, vel, time in new_notes:
            new_midi.addNote(0, 0, note, time, 100, vel)
        
        output = io.BytesIO()
        new_midi.writeFile(output)
        midi_data = base64.b64encode(output.getvalue()).decode('utf-8')
        self.modified_files.append(midi_data)
        return midi_data

    def apply_synth_effect(self, midi_id, effect_type, intensity):
        if midi_id not in self.loaded_midi:
            return None
        midi = self.loaded_midi[midi_id].copy()  # Work on a copy
        if effect_type == "tempo":
            factor = 1 + (intensity - 0.5) * 0.4  # -20% to +20%
            for track in midi.tracks:
                for event in track.events:
                    event.time = int(event.time * factor)
        elif effect_type == "pitch":
            shift = int((intensity - 0.5) * 12)  # -6 to +6 semitones
            for track in midi.tracks:
                for event in track.events:
                    if hasattr(event, 'note'):
                        event.note = min(127, max(0, event.note + shift))
        output = io.BytesIO()
        midi.writeFile(output)
        midi_data = base64.b64encode(output.getvalue()).decode('utf-8')
        self.modified_files.append(midi_data)
        return midi_data

    def play_with_loop(self, midi_data):
        self.is_playing = True
        midi_file = MIDI.load(io.BytesIO(base64.b64decode(midi_data)))
        while self.is_playing:
            self.synthesizer.play_midi(midi_file)
        return "Playback stopped"

    def stop_playback(self):
        self.is_playing = False
        return "Stopping playback..."

midi_manager = MIDIManager()

def create_download_list(modified_files):
    html = "<h3>Generated MIDI Files</h3><ul>"
    for i, data in enumerate(modified_files):
        html += f'<li><a href="data:audio/midi;base64,{data}" download="generated_midi_{i}.mid">Download MIDI {i}</a></li>'
    html += "</ul>"
    return html

with gr.Blocks(theme=gr.themes.Soft()) as app:
    gr.Markdown("<h1>🎵 MIDI Sequence Generator & Performer 🎵</h1>")
    
    with gr.Tabs():
        # Tab 1: MIDI Upload
        with gr.Tab("Upload MIDI"):
            midi_files = gr.File(label="Upload MIDI Files", file_count="multiple")
            midi_list = gr.State({})
            file_display = gr.HTML(value="No files loaded")
            
            def handle_upload(files):
                midi_list_val = {}
                html = "<h3>Loaded MIDI Files</h3>"
                for file in files:
                    midi_id, (notes, instruments) = midi_manager.load_midi(file.name)
                    midi_list_val[midi_id] = file.name
                    html += f'<div>{file.name} <button onclick="remove_midi(\'{midi_id}\')">X</button></div>'
                return midi_list_val, html
            
            midi_files.change(handle_upload, inputs=[midi_files], outputs=[midi_list, file_display])

        # Tab 2: Generate Variations
        with gr.Tab("Generate"):
            midi_select = gr.Dropdown(label="Select MIDI", choices=[])
            length_factor = gr.Slider(1, 10, value=2, step=1, label="Length Multiplier")
            variation_level = gr.Slider(0, 1, value=0.3, label="Variation Level")
            generate_btn = gr.Button("Generate Variation")
            generated_output = gr.Audio(label="Generated Preview", type="bytes")
            
            def update_dropdown(midi_list):
                return gr.update(choices=list(midi_list.keys()))
            
            midi_list.change(update_dropdown, inputs=[midi_list], outputs=[midi_select])
            
            def generate(midi_id, length, variation):
                if not midi_id:
                    return None
                midi_data = midi_manager.generate_variation(midi_id, length, variation)
                return io.BytesIO(base64.b64decode(midi_data))
            
            generate_btn.click(generate, inputs=[midi_select, length_factor, variation_level], 
                             outputs=[generated_output])

        # Tab 3: Synthesizer Controls
        with gr.Tab("Perform"):
            midi_play_select = gr.Dropdown(label="Select MIDI to Play", choices=[])
            synth_effects = gr.Radio(["tempo", "pitch"], label="Synth Effect", value="tempo")
            effect_intensity = gr.Slider(0, 1, value=0.5, label="Effect Intensity")
            apply_effect_btn = gr.Button("Apply Effect")
            play_btn = gr.Button("Play with Auto-Loop")
            stop_btn = gr.Button("Stop")
            playback_status = gr.Textbox(label="Playback Status", value="Stopped")
            
            midi_list.change(update_dropdown, inputs=[midi_list], outputs=[midi_play_select])
            
            def apply_and_preview(midi_id, effect, intensity):
                if not midi_id:
                    return None, "No MIDI selected"
                midi_data = midi_manager.apply_synth_effect(midi_id, effect, intensity)
                return io.BytesIO(base64.b64decode(midi_data)), "Effect applied"
            
            apply_effect_btn.click(apply_and_preview, 
                                 inputs=[midi_play_select, synth_effects, effect_intensity],
                                 outputs=[generated_output, playback_status])
            
            play_btn.click(midi_manager.play_with_loop, inputs=[generated_output], 
                          outputs=[playback_status])
            stop_btn.click(midi_manager.stop_playback, inputs=None, outputs=[playback_status])

        # Tab 4: Downloads
        with gr.Tab("Downloads"):
            download_list = gr.HTML(value="No generated files yet")
            def update_downloads(_):
                return create_download_list(midi_manager.modified_files)
            gr.on(triggers=[generate_btn.click, apply_effect_btn.click], 
                  fn=update_downloads, inputs=None, outputs=[download_list])

    # Hugging Face Branding
    gr.Markdown("""
    <div style='text-align: center; margin-top: 20px;'>
        <img src='https://huggingface.co/front/assets/huggingface_logo-noborder.svg' alt='Hugging Face Logo' style='width: 50px;'><br>
        <strong>Hugging Face</strong><br>
        <a href='https://huggingface.co/models'>Models</a> | 
        <a href='https://huggingface.co/datasets'>Datasets</a> | 
        <a href='https://huggingface.co/spaces'>Spaces</a> | 
        <a href='https://huggingface.co/posts'>Posts</a> | 
        <a href='https://huggingface.co/docs'>Docs</a> | 
        <a href='https://huggingface.co/enterprise'>Enterprise</a> | 
        <a href='https://huggingface.co/pricing'>Pricing</a>
    </div>
    """)

app.queue().launch(inbrowser=True)