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