#!/usr/bin/env python3
"""Bridge raw MIDI device to Pd via UDP. For host mode with MPK Mini.

Sends parsed MIDI messages as Pd-style 'midi status data1 data2;' strings
to UDP ports for Pd (8081) and LED matrix visualization (8082).
"""
import os, socket, time, select, struct

MIDI_DEV = os.environ.get("MIDI_BRIDGE_DEV", "/dev/snd/midiC0D0")
PD_HOST = os.environ.get("MIDI_BRIDGE_HOST", "127.0.0.1")
PD_PORT = int(os.environ.get("MIDI_BRIDGE_PORT", "8081"))
VIZ_PORT = int(os.environ.get("VIZ_PORT", "8082"))

def midi_msg(status, data1, data2=None):
    if data2 is not None:
        return f"midi {status} {data1} {data2};"
    return f"midi {status} {data1};"

def main():
    while not os.path.exists(MIDI_DEV):
        time.sleep(0.5)

    fd = os.open(MIDI_DEV, os.O_RDWR | os.O_NONBLOCK)
    os.set_blocking(fd, False)
    poll = select.poll()
    poll.register(fd, select.POLLIN)

    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

    running = True
    buf = bytearray()
    while running:
        try:
            events = poll.poll(500)
            for f, flags in events:
                if flags & select.POLLIN:
                    data = os.read(fd, 1024)
                    if not data:
                        continue
                    for byte in data:
                        if byte & 0x80:
                            if len(buf) > 0 and buf[0] >= 0x80:
                                _flush(sock, buf, PD_HOST, PD_PORT, VIZ_PORT)
                            buf = bytearray([byte])
                        else:
                            buf.append(byte)
                            if len(buf) >= 3 and (buf[0] & 0xE0) in (0x80, 0x90, 0xA0, 0xB0, 0xE0):
                                _flush(sock, buf, PD_HOST, PD_PORT, VIZ_PORT)
                                buf = bytearray()
                            elif len(buf) >= 2 and (buf[0] & 0xE0) in (0xC0, 0xD0):
                                _flush(sock, buf, PD_HOST, PD_PORT, VIZ_PORT)
                                buf = bytearray()
        except (BlockingIOError, OSError) as e:
            if isinstance(e, OSError) and e.errno == 19:
                time.sleep(1)
                continue
            if not isinstance(e, BlockingIOError):
                raise
        except KeyboardInterrupt:
            running = False

    os.close(fd)
    sock.close()

def _flush(sock, buf, pd_host, pd_port, viz_port):
    status = buf[0]
    if (buf[0] & 0xF0) == 0xF0:
        return
    data1 = buf[1]
    data2 = buf[2] if len(buf) >= 3 else None
    msg = midi_msg(status, data1, data2)
    sock.sendto(msg.encode(), (pd_host, pd_port))
    sock.sendto(msg.encode(), (pd_host, viz_port))

if __name__ == "__main__":
    main()