// src/contracts.rs
//! Cross-feature message contracts.
//! 
//! This is the ONLY coupling point between features.
//! Features depend on these types, not on each other.

use heapless::String as HString;

/// IMU sensor reading from MPU6050
#[derive(Clone, Copy, Default, Debug)]
pub struct ImuReading {
    /// Acceleration in g (earth gravity units)
    pub accel_g: [f32; 3],
    /// Angular velocity in degrees per second
    pub gyro_dps: [f32; 3],
    /// Temperature in Celsius
    pub temp_c: f32,
    /// Timestamp in milliseconds since boot
    pub timestamp_ms: u64,
}

/// Commands that can be sent to the display actor
#[derive(Clone, Debug)]
pub enum DisplayCommand {
    /// Show IMU sensor data
    SetImu(ImuReading),
    /// Show a status line (max 32 chars)
    SetStatus(HString<32>),
    /// Show an error message (max 64 chars)
    ShowError(HString<64>),
    /// Show MQTT connection status
    SetMqttStatus { connected: bool, msg_count: u32 },
    /// Clear the display to default state
    Clear,
}