P0: Rust engine, wire daemon and audio-reactive descent surface

2026-11-01 00:36:04 +03:00
parent cd967cced4
commit db4368efae
68 changed files with 19507 additions and 3 deletions
@@ -0,0 +1,340 @@
+//! ZHILA wire protocol, version 1.
+//!
+//! Text frames carry JSON control messages. Audio meters travel in a compact
+//! binary frame (see [`MeterFrame`]) at ~30 Hz, never inside JSON.
+
+use serde::{Deserialize, Serialize};
+
+pub const PROTOCOL_VERSION: u32 = 1;
+pub const VEIN_COUNT: usize = 5;
+pub const LOOP_STEPS: usize = 16;
+pub const STEPS_PER_BAR: usize = 8;
+pub const LOOP_BARS: f32 = 2.0;
+pub const MIN_BPM: f32 = 40.0;
+pub const MAX_BPM: f32 = 220.0;
+pub const MIN_GAIN: f32 = 0.0;
+pub const MAX_GAIN: f32 = 1.2;
+
+pub const METER_FRAME_KIND: u8 = 1;
+/// `kind (1) | count (2) | bar (4) | master (4) | levels (5 * 4)`
+pub const METER_FRAME_LEN: usize = 3 + 4 * (2 + VEIN_COUNT);
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
+#[serde(rename_all = "snake_case")]
+pub enum VeinId {
+    Bass,
+    Crack,
+    Voice,
+    Noise,
+    Silt,
+}
+
+impl VeinId {
+    pub const ALL: [VeinId; VEIN_COUNT] = [
+        VeinId::Bass,
+        VeinId::Crack,
+        VeinId::Voice,
+        VeinId::Noise,
+        VeinId::Silt,
+    ];
+
+    pub const fn index(self) -> usize {
+        match self {
+            VeinId::Bass => 0,
+            VeinId::Crack => 1,
+            VeinId::Voice => 2,
+            VeinId::Noise => 3,
+            VeinId::Silt => 4,
+        }
+    }
+
+    pub const fn name(self) -> &'static str {
+        match self {
+            VeinId::Bass => "bass",
+            VeinId::Crack => "crack",
+            VeinId::Voice => "voice",
+            VeinId::Noise => "noise",
+            VeinId::Silt => "silt",
+        }
+    }
+
+    pub const fn from_index(index: usize) -> Option<Self> {
+        match index {
+            0 => Some(VeinId::Bass),
+            1 => Some(VeinId::Crack),
+            2 => Some(VeinId::Voice),
+            3 => Some(VeinId::Noise),
+            4 => Some(VeinId::Silt),
+            _ => None,
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "snake_case")]
+pub enum Actor {
+    Hand,
+    Api,
+    Mcp,
+    System,
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+#[serde(tag = "type", rename_all = "snake_case")]
+pub enum ClientMessage {
+    Hello {
+        protocol: u32,
+        token: String,
+        client: String,
+    },
+    Command {
+        id: u64,
+        command: Command,
+    },
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+#[serde(tag = "type", rename_all = "snake_case")]
+pub enum ServerMessage {
+    Hello {
+        protocol: u32,
+        session: String,
+        engine: AudioInfo,
+    },
+    Snapshot {
+        revision: u64,
+        state: State,
+    },
+    Event {
+        revision: u64,
+        event: Event,
+    },
+    Result {
+        id: u64,
+        result: CommandResult,
+    },
+    Error {
+        id: Option<u64>,
+        code: ErrorCode,
+        message: String,
+    },
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+#[serde(tag = "type", rename_all = "snake_case")]
+pub enum Command {
+    GetSnapshot,
+    Play,
+    Stop,
+    Strike { vein: VeinId, velocity: f32 },
+    SetTempo { bpm: f32 },
+    SetVeinGain { vein: VeinId, gain: f32 },
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+#[serde(tag = "kind", rename_all = "snake_case")]
+pub enum CommandResult {
+    Snapshot { state: State },
+    State { state: State },
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+#[serde(tag = "kind", rename_all = "snake_case")]
+pub enum Event {
+    Transport { playing: bool },
+    Tempo { bpm: f32 },
+    VeinGain { vein: VeinId, gain: f32 },
+    Struck { vein: VeinId, velocity: f32 },
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "snake_case")]
+pub enum ErrorCode {
+    BadRequest,
+    Unauthorized,
+    Protocol,
+    Audio,
+    Internal,
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct AudioInfo {
+    pub running: bool,
+    pub device: String,
+    pub sample_rate: u32,
+    pub buffer_frames: u32,
+    pub channels: u16,
+}
+
+impl AudioInfo {
+    pub fn offline() -> Self {
+        Self {
+            running: false,
+            device: "none".into(),
+            sample_rate: 48_000,
+            buffer_frames: 0,
+            channels: 2,
+        }
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct State {
+    pub revision: u64,
+    pub transport: TransportState,
+    pub veins: Vec<VeinState>,
+    pub pattern: Pattern,
+    pub audio: AudioInfo,
+    pub journal_len: usize,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Serialize, Deserialize)]
+pub struct TransportState {
+    pub playing: bool,
+    pub bpm: f32,
+    pub bar: f32,
+    pub loop_bars: f32,
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct VeinState {
+    pub id: VeinId,
+    pub name: String,
+    pub gain: f32,
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct Pattern {
+    pub steps: u16,
+    pub steps_per_bar: u16,
+    pub rows: Vec<PatternRow>,
+}
+
+impl Pattern {
+    pub fn row(&self, vein: VeinId) -> Option<&PatternRow> {
+        self.rows.iter().find(|row| row.vein == vein)
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct PatternRow {
+    pub vein: VeinId,
+    /// One velocity per step, 0..=127. Zero means the step is empty.
+    pub velocities: Vec<u8>,
+}
+
+/// A single binary meter frame. Text frames never carry audio-rate data.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct MeterFrame {
+    pub bar: f32,
+    pub master: f32,
+    pub veins: [f32; VEIN_COUNT],
+}
+
+impl MeterFrame {
+    pub fn silent() -> Self {
+        Self {
+            bar: 1.0,
+            master: 0.0,
+            veins: [0.0; VEIN_COUNT],
+        }
+    }
+
+    pub fn encode(&self) -> Vec<u8> {
+        let mut out = Vec::with_capacity(METER_FRAME_LEN);
+        out.push(METER_FRAME_KIND);
+        out.extend_from_slice(&(VEIN_COUNT as u16).to_le_bytes());
+        out.extend_from_slice(&self.bar.to_le_bytes());
+        out.extend_from_slice(&self.master.to_le_bytes());
+        for level in self.veins {
+            out.extend_from_slice(&level.to_le_bytes());
+        }
+        debug_assert_eq!(out.len(), METER_FRAME_LEN);
+        out
+    }
+
+    pub fn decode(data: &[u8]) -> Option<Self> {
+        if data.len() != METER_FRAME_LEN || data[0] != METER_FRAME_KIND {
+            return None;
+        }
+        let count = u16::from_le_bytes([data[1], data[2]]) as usize;
+        if count != VEIN_COUNT {
+            return None;
+        }
+        let bar = read_f32(data, 3)?;
+        let master = read_f32(data, 7)?;
+        let mut veins = [0.0; VEIN_COUNT];
+        for (index, level) in veins.iter_mut().enumerate() {
+            *level = read_f32(data, 11 + index * 4)?;
+        }
+        Some(Self { bar, master, veins })
+    }
+}
+
+fn read_f32(data: &[u8], offset: usize) -> Option<f32> {
+    let bytes: [u8; 4] = data.get(offset..offset + 4)?.try_into().ok()?;
+    Some(f32::from_le_bytes(bytes))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn hello_roundtrip() {
+        let message = ClientMessage::Hello {
+            protocol: PROTOCOL_VERSION,
+            token: "dev".into(),
+            client: "ui".into(),
+        };
+        let json = serde_json::to_string(&message).unwrap();
+        assert!(json.contains("\"type\":\"hello\""));
+        let back: ClientMessage = serde_json::from_str(&json).unwrap();
+        assert_eq!(back, message);
+    }
+
+    #[test]
+    fn command_roundtrip() {
+        let message = ClientMessage::Command {
+            id: 7,
+            command: Command::Strike {
+                vein: VeinId::Bass,
+                velocity: 0.8,
+            },
+        };
+        let json = serde_json::to_string(&message).unwrap();
+        let back: ClientMessage = serde_json::from_str(&json).unwrap();
+        assert_eq!(back, message);
+    }
+
+    #[test]
+    fn meter_roundtrip_is_exact() {
+        let frame = MeterFrame {
+            bar: 2.75,
+            master: 0.42,
+            veins: [0.1, 0.2, 0.3, 0.4, 0.5],
+        };
+        let bytes = frame.encode();
+        assert_eq!(bytes.len(), METER_FRAME_LEN);
+        let back = MeterFrame::decode(&bytes).expect("valid frame");
+        assert_eq!(back, frame);
+    }
+
+    #[test]
+    fn meter_rejects_garbage() {
+        assert!(MeterFrame::decode(&[]).is_none());
+        assert!(MeterFrame::decode(&[METER_FRAME_KIND; 4]).is_none());
+        let mut bytes = MeterFrame::silent().encode();
+        bytes[0] = 9;
+        assert!(MeterFrame::decode(&bytes).is_none());
+    }
+
+    #[test]
+    fn vein_indices_are_stable() {
+        for (index, vein) in VeinId::ALL.iter().enumerate() {
+            assert_eq!(vein.index(), index);
+            assert_eq!(VeinId::from_index(index), Some(*vein));
+        }
+        assert_eq!(VeinId::from_index(VEIN_COUNT), None);
+    }
+}