max / audiofiles

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1	//! MIDI input: enumerate ports, connect/disconnect, and parse incoming messages.
2
3	use std::sync::Arc;
4	use std::time::Instant;
5
6	use audiofiles_browser::state::{MidiNoteEvent, SharedState};
7	use audiofiles_core::instrument::note_name;
8	use midir::{ConnectError, InitError, MidiInput, MidiInputConnection};
9	use thiserror::Error;
10	use tracing::instrument;
11
12	/// An active MIDI input connection. Dropping this disconnects.
13	pub struct MidiConnection {
14	_conn: MidiInputConnection<()>,
15	}
16
17	/// Errors from MIDI port enumeration and connection.
18	#[derive(Error, Debug)]
19	pub enum MidiError {
20	#[error("MIDI init: {0}")]
21	Init(#[from] InitError),
22	#[error("MIDI port index {idx} out of range ({count} ports available)")]
23	PortOutOfRange { idx: usize, count: usize },
24	#[error("MIDI connect: {0}")]
25	Connect(#[from] ConnectError<MidiInput>),
26	}
27
28	/// List available MIDI input port names.
29	#[instrument(skip_all)]
30	pub fn list_input_ports() -> Vec<String> {
31	let Ok(midi_in) = MidiInput::new("audiofiles-enumerate") else {
32	return Vec::new();
33	};
34	midi_in
35	.ports()
36	.iter()
37	.filter_map(\|p\| midi_in.port_name(p).ok())
38	.collect()
39	}
40
41	/// Connect to a MIDI input port by index.
42	///
43	/// The callback parses note-on/note-off messages and calls `note_on`/`note_off`
44	/// on the instrument directly (low latency). Also pushes `MidiNoteEvent`s to
45	/// `shared.midi_recent_notes` for the GUI activity display.
46	#[instrument(skip_all)]
47	pub fn connect(port_index: usize, shared: Arc<SharedState>) -> Result<MidiConnection, MidiError> {
48	let midi_in = MidiInput::new("audiofiles-input")?;
49	let ports = midi_in.ports();
50	let port = ports
51	.get(port_index)
52	.ok_or(MidiError::PortOutOfRange { idx: port_index, count: ports.len() })?;
53
54	let shared_cb = shared.clone();
55	let conn = midi_in
56	.connect(
57	port,
58	"audiofiles-midi-in",
59	move \|_timestamp, message, _\| {
60	if message.len() < 3 {
61	return;
62	}
63	let status = message[0] & 0xF0;
64	let note = message[1];
65	let velocity = message[2];
66
67	match status {
68	0x90 if velocity > 0 => {
69	// Note On
70	shared_cb.instrument.lock().note_on(note, velocity);
71	shared_cb.midi_recent_notes.lock().push(MidiNoteEvent {
72	note,
73	velocity,
74	note_name: note_name(note),
75	timestamp: Instant::now(),
76	});
77	}
78	0x80 \| 0x90 => {
79	// Note Off (0x80 or 0x90 with velocity 0)
80	shared_cb.instrument.lock().note_off(note);
81	}
82	_ => {}
83	}
84	},
85	(),
86	)?;
87
88	Ok(MidiConnection { _conn: conn })
89	}
90