import mido
import argparse
import sys
import os

def remove_redundant_midi(input_path, verbose=False):
    """
    Removes redundant MIDI data from the input MIDI file and saves the cleaned file
    with '_redundancy_check' appended to the original filename.

    Args:
        input_path (str): Path to the input MIDI file.
        verbose (bool): If True, prints detailed processing information.
    """
    try:
        midi = mido.MidiFile(input_path)
        if verbose:
            print(f"Loaded MIDI file '{input_path}' successfully.")
    except IOError:
        print(f"Error: Cannot open input MIDI file '{input_path}'. Please check the path.")
        sys.exit(1)
    except mido.KeySignatureError as e:
        print(f"Error reading MIDI file: {e}")
        sys.exit(1)

    cleaned_midi = mido.MidiFile()
    cleaned_midi.ticks_per_beat = midi.ticks_per_beat

    total_messages = 0
    removed_messages = 0

    for i, track in enumerate(midi.tracks):
        cleaned_track = mido.MidiTrack()
        last_state = {}  # To keep track of the last control change or similar messages
        last_msg = None
        track_removed = 0
        track_total = 0

        for msg in track:
            track_total += 1
            total_messages += 1

            # Remove consecutive duplicate messages
            if last_msg is not None and msg == last_msg:
                if verbose:
                    print(f"Track {i}: Removed duplicate message {msg}")
                removed_messages += 1
                track_removed += 1
                continue

            # Remove redundant control change messages
            if msg.type in ['control_change', 'program_change', 'pitchwheel', 'aftertouch', 'channel_pressure']:
                channel = msg.channel
                key = f"{msg.type}_{channel}"
                if key in last_state and last_state[key] == msg:
                    if verbose:
                        print(f"Track {i}: Removed redundant state message {msg}")
                    removed_messages += 1
                    track_removed += 1
                    continue  # Redundant state message
                last_state[key] = msg
                cleaned_track.append(msg)
            # Remove redundant note_off messages if note_on with velocity 0 is used
            elif msg.type == 'note_off':
                # Depending on MIDI implementation, decide if it's redundant
                # For this script, we'll assume they are necessary and keep them
                cleaned_track.append(msg)
            elif msg.type == 'note_on' and msg.velocity == 0:
                # This is equivalent to note_off; decide whether to keep or remove note_off messages
                # For simplicity, keep both
                cleaned_track.append(msg)
            else:
                # For all other message types, simply append if not duplicate
                cleaned_track.append(msg)

            last_msg = msg

        cleaned_midi.tracks.append(cleaned_track)
        if verbose:
            print(f"Track {i}: Processed {track_total} messages, removed {track_removed} redundant messages.")

    # Generate the output file name by appending '_redundancy_check' before the file extension
    base, ext = os.path.splitext(input_path)
    output_path = f"{base}_redundancy_check{ext}"

    try:
        cleaned_midi.save(output_path)
        if verbose:
            print(f"Saved cleaned MIDI to '{output_path}'.")
            print(f"Total messages processed: {total_messages}")
            print(f"Total messages removed: {removed_messages}")
        else:
            print(f"Successfully saved cleaned MIDI to '{output_path}'.")
    except IOError:
        print(f"Error: Cannot write to output file '{output_path}'. Please check the path and permissions.")
        sys.exit(1)

def parse_arguments():
    """
    Parses command-line arguments.

    Returns:
        argparse.Namespace: The parsed arguments.
    """
    parser = argparse.ArgumentParser(description="Remove redundant MIDI data from a MIDI file and save the cleaned file with '_redundancy_check' appended to the filename.")
    parser.add_argument('input_midi', type=str, help='Path to the input MIDI file.')
    parser.add_argument('-v', '--verbose', action='store_true', help='Enable verbose output.')

    return parser.parse_args()

def main():
    args = parse_arguments()

    # Check if input file exists
    if not os.path.isfile(args.input_midi):
        print(f"Error: The input file '{args.input_midi}' does not exist.")
        sys.exit(1)

    remove_redundant_midi(args.input_midi, args.verbose)

if __name__ == "__main__":
    main()