autocore-std 3.3.34

use crate::motion::{
    AxisView,
    cia402::{
        Cia402Control, Cia402Status, Cia402State, ModesOfOperation,
        PpControl, PpStatus,
        HomingControl, HomingStatus,
    },
};
use crate::ethercat::teknic::types::{
    TeknicPpControlWord, TeknicPpStatusWord,
    TeknicPpControl, TeknicPpStatus,
    TeknicHomingControlWord, TeknicHomingStatusWord,
};

// ──────────────────────────────────────────────
// HomingProgress
// ──────────────────────────────────────────────

/// Homing procedure progress, decoded from status word bits 10, 12, 13.
///
/// | Error (13) | Attained (12) | Reached (10) | Progress     |
/// |------------|---------------|--------------|--------------|
/// | 0          | 0             | 1            | `Idle`       |
/// | 0          | 0             | 0            | `InProgress` |
/// | 0          | 1             | 0            | `Attained`   |
/// | 0          | 1             | 1            | `Complete`   |
/// | 1          | x             | x            | `Error`      |
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum HomingProgress {
    /// Homing not started or interrupted (motor stationary).
    Idle,
    /// Homing actively in progress (motor searching).
    InProgress,
    /// Reference found; offset move still in progress.
    Attained,
    /// Homing completed successfully — position is now referenced.
    Complete,
    /// A homing error occurred (motor may still be moving).
    Error,
}

impl std::fmt::Display for HomingProgress {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::Idle       => write!(f, "Idle"),
            Self::InProgress => write!(f, "In Progress"),
            Self::Attained   => write!(f, "Attained"),
            Self::Complete   => write!(f, "Complete"),
            Self::Error      => write!(f, "Error"),
        }
    }
}

// ──────────────────────────────────────────────
// TeknicPpView — borrowed view for one axis
// ──────────────────────────────────────────────

/// A borrowed view into GlobalMemory for one Teknic ClearPath axis.
///
/// Supports both **Profile Position (PP)** moves and the **Homing**
/// phase that typically precedes them. Holds mutable references to
/// RxPDO (output) fields and shared references to TxPDO (input) fields.
/// Reuse the same struct for multiple axes — just point the references
/// at different GlobalMemory fields via [`teknic_pp_view!`].
///
/// # Homing Example
///
/// Homing is performed once at startup. Configure homing parameters
/// (method, speeds, acceleration) via SDO before entering the control
/// loop.
///
/// ```ignore
/// use crate::teknic::view::{TeknicPpView, HomingProgress};
/// use crate::motion::types::{Cia402State, ModesOfOperation};
///
/// #[derive(Debug, Clone, Copy, PartialEq)]
/// enum HomingState {
///     Init,
///     WaitMode,
///     WaitComplete,
///     Done,
///     Failed,
/// }
///
/// fn tick_homing(view: &mut TeknicPpView, state: &mut HomingState) {
///     if view.is_faulted() && *state != HomingState::Failed {
///         log::error!("Drive fault during homing");
///         *state = HomingState::Failed;
///     }
///
///     match state {
///         HomingState::Init => {
///             view.ensure_homing_mode();
///             view.cmd_enable_operation();
///             *state = HomingState::WaitMode;
///         }
///         HomingState::WaitMode => {
///             if view.state() == Cia402State::OperationEnabled
///                 && view.current_mode() == Some(ModesOfOperation::Homing)
///             {
///                 view.trigger_homing();
///                 *state = HomingState::WaitComplete;
///             }
///         }
///         HomingState::WaitComplete => {
///             match view.homing_progress() {
///                 HomingProgress::Complete => {
///                     view.clear_homing_start();
///                     log::info!("Homing complete at pos {}", view.position());
///                     *state = HomingState::Done;
///                 }
///                 HomingProgress::Error => {
///                     log::error!("Homing error!");
///                     *state = HomingState::Failed;
///                 }
///                 _ => {} // still in progress
///             }
///         }
///         HomingState::Done => {
///             // Switch to PP mode for positioning.
///             view.ensure_pp_mode();
///         }
///         HomingState::Failed => {
///             view.cmd_fault_reset();
///             if view.state() == Cia402State::SwitchOnDisabled {
///                 *state = HomingState::Init;
///             }
///         }
///     }
/// }
/// ```
///
/// # Profile Position Example
///
/// After homing, use PP mode to make absolute or relative moves.
///
/// ```ignore
/// use crate::teknic::view::TeknicPpView;
/// use crate::motion::types::Cia402State;
///
/// #[derive(Debug, Clone, Copy, PartialEq)]
/// enum MoveState {
///     Init,
///     WaitReady,
///     WaitEnabled,
///     StartMove,
///     WaitAck,
///     WaitComplete,
///     Done,
///     Faulted,
/// }
///
/// fn tick_move(view: &mut TeknicPpView, state: &mut MoveState) {
///     if view.is_faulted() && *state != MoveState::Faulted {
///         log::error!("Drive fault detected in state {:?}", state);
///         *state = MoveState::Faulted;
///     }
///
///     match state {
///         MoveState::Init => {
///             view.ensure_pp_mode();
///             view.cmd_shutdown();           // → Ready to Switch On
///             *state = MoveState::WaitReady;
///         }
///         MoveState::WaitReady => {
///             if view.state() == Cia402State::ReadyToSwitchOn {
///                 view.cmd_enable_operation(); // → Operation Enabled
///                 *state = MoveState::WaitEnabled;
///             }
///         }
///         MoveState::WaitEnabled => {
///             if view.state() == Cia402State::OperationEnabled {
///                 *state = MoveState::StartMove;
///             }
///         }
///         MoveState::StartMove => {
///             // Absolute move to 100 000 counts at 50 000 cts/s
///             view.set_target(100_000, 50_000, 10_000, 10_000);
///             view.set_relative(false);      // absolute move
///             view.trigger_move();
///             *state = MoveState::WaitAck;
///         }
///         MoveState::WaitAck => {
///             if view.set_point_acknowledged() {
///                 view.ack_set_point();       // complete handshake
///                 *state = MoveState::WaitComplete;
///             }
///         }
///         MoveState::WaitComplete => {
///             if view.following_error() {
///                 log::error!("Following error at pos {}", view.position());
///                 *state = MoveState::Faulted;
///             } else if view.target_reached() && view.in_range() {
///                 *state = MoveState::Done;
///             }
///         }
///         MoveState::Done => {
///             // Move complete — start another or disable the drive.
///         }
///         MoveState::Faulted => {
///             view.cmd_fault_reset();
///             if view.state() == Cia402State::SwitchOnDisabled {
///                 *state = MoveState::Init;   // recovered, restart
///             }
///         }
///     }
/// }
/// ```
pub struct TeknicPpView<'a> {
    // ── RxPDO — master → drive ──
    pub control_word: &'a mut u16,
    pub target_position: &'a mut i32,
    pub profile_velocity: &'a mut u32,
    pub profile_acceleration: &'a mut u32,
    pub profile_deceleration: &'a mut u32,
    pub modes_of_operation: &'a mut i8,

    // ── TxPDO — drive → master ──
    pub status_word: &'a u16,
    pub position_actual: &'a i32,
    pub velocity_actual: &'a i32,
    pub torque_actual: &'a i16,
    pub modes_of_operation_display: &'a i8,
}

/// Teknic-specific convenience methods for `TeknicPpView` (borrowed).
/// The macro parameter `$deref` controls whether field access dereferences
/// a reference (`*`) or reads directly. Includes both standard CiA 402 methods
/// and Teknic vendor-specific extensions (has_homed, in_range, at_velocity).
macro_rules! impl_teknic_pp_methods {
    ($T:ty, deref: $($d:tt)*) => {
        impl $T {
            // ── Typed access ──

            /// Read the control word as a typed Teknic PP control word.
            pub fn pp_control(&self) -> TeknicPpControlWord {
                TeknicPpControlWord($($d)* self.control_word)
            }

            /// Read the status word as a typed Teknic PP status word.
            pub fn pp_status(&self) -> TeknicPpStatusWord {
                TeknicPpStatusWord($($d)* self.status_word)
            }

            /// Write back a modified PP control word.
            pub fn set_pp_control(&mut self, cw: TeknicPpControlWord) {
                $($d)* self.control_word = cw.raw();
            }

            // ── State machine ──

            /// Current CiA 402 state.
            pub fn state(&self) -> Cia402State {
                self.pp_status().state()
            }

            /// Shutdown → Ready to Switch On.
            pub fn cmd_shutdown(&mut self) {
                let mut cw = self.pp_control();
                cw.cmd_shutdown();
                self.set_pp_control(cw);
            }

            /// Switch On → Switched On.
            pub fn cmd_switch_on(&mut self) {
                let mut cw = self.pp_control();
                cw.cmd_switch_on();
                self.set_pp_control(cw);
            }

            /// Enable Operation → Operation Enabled.
            pub fn cmd_enable_operation(&mut self) {
                let mut cw = self.pp_control();
                cw.cmd_enable_operation();
                self.set_pp_control(cw);
            }

            /// Disable Operation → Switched On.
            pub fn cmd_disable_operation(&mut self) {
                let mut cw = self.pp_control();
                cw.cmd_disable_operation();
                self.set_pp_control(cw);
            }

            /// Disable Voltage → Switch On Disabled.
            pub fn cmd_disable_voltage(&mut self) {
                let mut cw = self.pp_control();
                cw.cmd_disable_voltage();
                self.set_pp_control(cw);
            }

            /// Quick Stop → Quick Stop Active.
            pub fn cmd_quick_stop(&mut self) {
                let mut cw = self.pp_control();
                cw.cmd_quick_stop();
                self.set_pp_control(cw);
            }

            /// Fault Reset (rising edge on bit 7).
            pub fn cmd_fault_reset(&mut self) {
                let mut cw = self.pp_control();
                cw.cmd_fault_reset();
                self.set_pp_control(cw);
            }

            /// Clear/reset Fault Reset bit (bit 7).
            pub fn cmd_clear_fault_reset(&mut self) {
                let mut cw = self.pp_control();
                cw.cmd_clear_fault_reset();
                self.set_pp_control(cw);
            }

            // ── PP motion ──

            /// Set mode to Profile Position.
            pub fn ensure_pp_mode(&mut self) {
                $($d)* self.modes_of_operation = ModesOfOperation::ProfilePosition.as_i8();
            }

            /// Configure move parameters (does not trigger the move).
            pub fn set_target(&mut self, position: i32, velocity: u32, accel: u32, decel: u32) {
                $($d)* self.target_position = position;
                $($d)* self.profile_velocity = velocity;
                $($d)* self.profile_acceleration = accel;
                $($d)* self.profile_deceleration = decel;
            }

            /// Assert New Set-Point (bit 4). Call after set_target().
            pub fn trigger_move(&mut self) {
                let mut cw = self.pp_control();
                cw.set_new_set_point(true);
                self.set_pp_control(cw);
            }

            /// Clear New Set-Point. Call when set_point_acknowledged() is true.
            pub fn ack_set_point(&mut self) {
                let mut cw = self.pp_control();
                cw.set_new_set_point(false);
                self.set_pp_control(cw);
            }

            /// Bit 8 — Halt: decelerate to stop.
            pub fn set_halt(&mut self, v: bool) {
                let mut cw = self.pp_control();
                cw.set_halt(v);
                self.set_pp_control(cw);
            }

            /// Bit 6 — Relative: when true, target_position is relative to the
            /// current *command* position. When false, target_position is absolute.
            pub fn set_relative(&mut self, v: bool) {
                let mut cw = self.pp_control();
                cw.set_relative(v);
                self.set_pp_control(cw);
            }

            /// Bit 13 (Teknic) — Relative to Actual: when true *and* bit 6 is set,
            /// target_position is relative to the *actual* position rather than the
            /// command position. Only meaningful when `set_relative(true)`.
            pub fn set_relative_to_actual(&mut self, v: bool) {
                let mut cw = self.pp_control();
                cw.set_relative_to_actual(v);
                self.set_pp_control(cw);
            }

            // ── PP status queries ──

            /// Drive has reached the target position.
            pub fn target_reached(&self) -> bool {
                self.pp_status().pp_target_reached()
            }

            /// Set-point was acknowledged by the drive.
            pub fn set_point_acknowledged(&self) -> bool {
                self.pp_status().set_point_acknowledge()
            }

            /// Teknic: position within in-range window.
            pub fn in_range(&self) -> bool {
                self.pp_status().in_range()
            }

            /// Teknic bit 8 — Has Homed: persistent flag that remains set after any
            /// successful homing procedure, even after switching back to PP or PV mode.
            pub fn has_homed(&self) -> bool {
                self.pp_status().has_homed()
            }

            /// Teknic: actual velocity has reached target.
            pub fn at_velocity(&self) -> bool {
                self.pp_status().at_velocity()
            }

            // ── Error / fault status ──

            /// Bit 13 — Following Error: position tracking error exceeded the
            /// configured limit. Typically leads to a fault transition.
            pub fn following_error(&self) -> bool {
                self.pp_status().following_error()
            }

            /// Bit 11 — Internal Limit Active: a hardware or software limit
            /// is currently active (e.g. position or velocity limit).
            pub fn internal_limit(&self) -> bool {
                self.pp_status().internal_limit()
            }

            /// Bit 7 — Warning: a non-fatal warning condition exists.
            pub fn warning(&self) -> bool {
                self.pp_status().warning()
            }

            /// True if the drive is in Fault or Fault Reaction Active state.
            pub fn is_faulted(&self) -> bool {
                matches!(self.state(), Cia402State::Fault | Cia402State::FaultReactionActive)
            }

            // ── Homing ──

            /// Set mode to Homing.
            pub fn ensure_homing_mode(&mut self) {
                $($d)* self.modes_of_operation = ModesOfOperation::Homing.as_i8();
            }

            /// Start the homing procedure (rising edge on bit 4).
            pub fn trigger_homing(&mut self) {
                let mut cw = TeknicHomingControlWord($($d)* self.control_word);
                cw.set_homing_start(true);
                $($d)* self.control_word = cw.raw();
            }

            /// Clear the homing start bit. Call after homing completes.
            pub fn clear_homing_start(&mut self) {
                let mut cw = TeknicHomingControlWord($($d)* self.control_word);
                cw.set_homing_start(false);
                $($d)* self.control_word = cw.raw();
            }

            /// Decode the current homing progress from status word bits 10, 12, 13.
            pub fn homing_progress(&self) -> HomingProgress {
                let sw = TeknicHomingStatusWord($($d)* self.status_word);
                let attained = sw.homing_attained();
                let reached  = sw.homing_target_reached();
                let error    = sw.homing_error();

                if error {
                    HomingProgress::Error
                } else if attained && reached {
                    HomingProgress::Complete
                } else if attained {
                    HomingProgress::Attained
                } else if reached {
                    HomingProgress::Idle
                } else {
                    HomingProgress::InProgress
                }
            }

            // ── Feedback ──

            /// Actual position in encoder counts.
            pub fn position(&self) -> i32 {
                $($d)* self.position_actual
            }

            /// Actual velocity in encoder counts/s.
            pub fn velocity(&self) -> i32 {
                $($d)* self.velocity_actual
            }

            /// Actual torque in per-mille of rated torque.
            pub fn torque(&self) -> i16 {
                $($d)* self.torque_actual
            }

            /// Mode the drive is currently operating in.
            pub fn current_mode(&self) -> Option<ModesOfOperation> {
                ModesOfOperation::from_i8($($d)* self.modes_of_operation_display)
            }
        }
    };
}

// Apply shared methods to TeknicPpView (dereferences references)
impl_teknic_pp_methods!(TeknicPpView<'_>, deref: *);

// ──────────────────────────────────────────────
// AxisView implementation for TeknicPpView
// ──────────────────────────────────────────────

impl AxisView for TeknicPpView<'_> {
    fn control_word(&self) -> u16 { *self.control_word }
    fn set_control_word(&mut self, word: u16) { *self.control_word = word; }
    fn status_word(&self) -> u16 { *self.status_word }
    fn set_target_position(&mut self, pos: i32) { *self.target_position = pos; }
    fn set_profile_velocity(&mut self, vel: u32) { *self.profile_velocity = vel; }
    fn set_profile_acceleration(&mut self, accel: u32) { *self.profile_acceleration = accel; }
    fn set_profile_deceleration(&mut self, decel: u32) { *self.profile_deceleration = decel; }
    fn set_modes_of_operation(&mut self, mode: i8) { *self.modes_of_operation = mode; }
    fn modes_of_operation_display(&self) -> i8 { *self.modes_of_operation_display }
    fn position_actual(&self) -> i32 { *self.position_actual }
    fn velocity_actual(&self) -> i32 { *self.velocity_actual }
    // error_code: uses default (0) — Teknic error code not in standard view fields
}

// ──────────────────────────────────────────────
// View factory macro
// ──────────────────────────────────────────────

/// Create a [`TeknicPpView`] by projecting GlobalMemory fields with a common prefix.
///
/// Fields must follow the naming convention `{prefix}_control_word`,
/// `{prefix}_target_position`, etc.
///
/// # Example
///
/// ```ignore
/// let mut view = teknic_pp_view!(ctx.gm, axis1);
/// view.ensure_pp_mode();
/// view.cmd_enable_operation();
/// view.set_target(10_000, 5_000, 1_000, 1_000);
/// view.trigger_move();
/// ```
#[macro_export]
macro_rules! teknic_pp_view {
    ($gm:expr, $prefix:ident) => {
        paste::paste! {
            $crate::teknic::view::TeknicPpView {
                control_word:              &mut $gm.[<$prefix _control_word>],
                target_position:           &mut $gm.[<$prefix _target_position>],
                profile_velocity:          &mut $gm.[<$prefix _profile_velocity>],
                profile_acceleration:      &mut $gm.[<$prefix _profile_acceleration>],
                profile_deceleration:      &mut $gm.[<$prefix _profile_deceleration>],
                modes_of_operation:        &mut $gm.[<$prefix _modes_of_operation>],
                status_word:               & $gm.[<$prefix _status_word>],
                position_actual:           & $gm.[<$prefix _position_actual>],
                velocity_actual:           & $gm.[<$prefix _velocity_actual>],
                torque_actual:             & $gm.[<$prefix _torque_actual>],
                modes_of_operation_display: & $gm.[<$prefix _modes_of_operation_display>],
            }
        }
    };
}

// ──────────────────────────────────────────────
// Tests
// ──────────────────────────────────────────────

#[cfg(test)]
mod tests {
    use super::*;

    /// Local storage for PDO fields used in tests. Avoids depending on
    /// auto-generated GlobalMemory field names.
    #[derive(Default)]
    struct TestPdo {
        control_word: u16,
        target_position: i32,
        profile_velocity: u32,
        profile_acceleration: u32,
        profile_deceleration: u32,
        modes_of_operation: i8,
        status_word: u16,
        position_actual: i32,
        velocity_actual: i32,
        torque_actual: i16,
        modes_of_operation_display: i8,
    }

    impl TestPdo {
        fn view(&mut self) -> TeknicPpView<'_> {
            TeknicPpView {
                control_word:              &mut self.control_word,
                target_position:           &mut self.target_position,
                profile_velocity:          &mut self.profile_velocity,
                profile_acceleration:      &mut self.profile_acceleration,
                profile_deceleration:      &mut self.profile_deceleration,
                modes_of_operation:        &mut self.modes_of_operation,
                status_word:               &self.status_word,
                position_actual:           &self.position_actual,
                velocity_actual:           &self.velocity_actual,
                torque_actual:             &self.torque_actual,
                modes_of_operation_display: &self.modes_of_operation_display,
            }
        }
    }

    // ── State machine ──

    #[test]
    fn test_view_reads_state() {
        let mut pdo = TestPdo { status_word: 0x0040, ..Default::default() };
        let view = pdo.view();
        assert_eq!(view.state(), Cia402State::SwitchOnDisabled);
    }

    #[test]
    fn test_view_cmd_shutdown() {
        let mut pdo = TestPdo { status_word: 0x0040, ..Default::default() };
        let mut view = pdo.view();
        view.cmd_shutdown();
        assert_eq!(*view.control_word & 0x008F, 0x0006);
    }

    #[test]
    fn test_view_cmd_enable_operation() {
        let mut pdo = TestPdo::default();
        let mut view = pdo.view();
        view.cmd_enable_operation();
        assert_eq!(*view.control_word & 0x008F, 0x000F);
    }

    // ── PP motion ──

    #[test]
    fn test_view_set_target_and_trigger() {
        let mut pdo = TestPdo::default();
        let mut view = pdo.view();
        view.cmd_enable_operation();
        view.set_target(50_000, 10_000, 2_000, 2_000);
        view.trigger_move();

        assert_eq!(*view.target_position, 50_000);
        assert_eq!(*view.profile_velocity, 10_000);
        assert_eq!(*view.profile_acceleration, 2_000);
        assert_eq!(*view.profile_deceleration, 2_000);
        assert!(*view.control_word & (1 << 4) != 0);
    }

    #[test]
    fn test_view_ack_set_point() {
        let mut pdo = TestPdo::default();
        let mut view = pdo.view();
        view.cmd_enable_operation();
        view.trigger_move();
        assert!(*view.control_word & (1 << 4) != 0);

        view.ack_set_point();
        assert!(*view.control_word & (1 << 4) == 0);
        assert_eq!(*view.control_word & 0x000F, 0x000F);
    }

    #[test]
    fn test_view_absolute_move() {
        let mut pdo = TestPdo::default();
        let mut view = pdo.view();
        view.cmd_enable_operation();
        view.set_relative(false);
        view.set_target(100_000, 50_000, 10_000, 10_000);
        view.trigger_move();

        assert_eq!(*view.control_word & (1 << 6), 0);
        assert!(*view.control_word & (1 << 4) != 0);
    }

    #[test]
    fn test_view_relative_move() {
        let mut pdo = TestPdo::default();
        let mut view = pdo.view();
        view.cmd_enable_operation();
        view.set_relative(true);
        view.set_target(5_000, 10_000, 2_000, 2_000);
        view.trigger_move();

        assert!(*view.control_word & (1 << 6) != 0);
    }

    #[test]
    fn test_view_relative_to_actual() {
        let mut pdo = TestPdo::default();
        let mut view = pdo.view();
        view.cmd_enable_operation();
        view.set_relative(true);
        view.set_relative_to_actual(true);
        view.set_target(1_000, 5_000, 1_000, 1_000);
        view.trigger_move();

        assert!(*view.control_word & (1 << 6) != 0);
        assert!(*view.control_word & (1 << 13) != 0);
    }

    // ── Feedback ──

    #[test]
    fn test_view_feedback() {
        let mut pdo = TestPdo {
            position_actual: 12345,
            velocity_actual: -500,
            torque_actual: 100,
            modes_of_operation_display: 1,
            ..Default::default()
        };
        let view = pdo.view();

        assert_eq!(view.position(), 12345);
        assert_eq!(view.velocity(), -500);
        assert_eq!(view.torque(), 100);
        assert_eq!(view.current_mode(), Some(ModesOfOperation::ProfilePosition));
    }

    #[test]
    fn test_view_teknic_status_bits() {
        let mut pdo = TestPdo {
            // Operation Enabled (0x27) + has_homed (bit 8) + in_range (bit 15)
            status_word: 0x8127,
            ..Default::default()
        };
        let view = pdo.view();

        assert_eq!(view.state(), Cia402State::OperationEnabled);
        assert!(view.has_homed());
        assert!(view.in_range());
        assert!(!view.at_velocity());
    }

    #[test]
    fn test_view_ensure_pp_mode() {
        let mut pdo = TestPdo::default();
        let mut view = pdo.view();
        view.ensure_pp_mode();
        assert_eq!(*view.modes_of_operation, 1);
    }

    // ── Error / fault ──

    #[test]
    fn test_view_following_error() {
        let mut pdo = TestPdo {
            // Operation Enabled (0x27) + following error (bit 13)
            status_word: 0x2027,
            ..Default::default()
        };
        let view = pdo.view();

        assert_eq!(view.state(), Cia402State::OperationEnabled);
        assert!(view.following_error());
        assert!(!view.is_faulted());
    }

    #[test]
    fn test_view_internal_limit() {
        let mut pdo = TestPdo { status_word: 0x0827, ..Default::default() };
        let view = pdo.view();
        assert!(view.internal_limit());
    }

    #[test]
    fn test_view_warning() {
        let mut pdo = TestPdo { status_word: 0x00A7, ..Default::default() };
        let view = pdo.view();
        assert_eq!(view.state(), Cia402State::OperationEnabled);
        assert!(view.warning());
    }

    #[test]
    fn test_view_is_faulted() {
        let mut pdo = TestPdo::default();

        pdo.status_word = 0x0008; // Fault
        let view = pdo.view();
        assert!(view.is_faulted());
        assert_eq!(view.state(), Cia402State::Fault);

        pdo.status_word = 0x000F; // Fault Reaction Active
        let view = pdo.view();
        assert!(view.is_faulted());

        pdo.status_word = 0x0027; // Operation Enabled — not faulted
        let view = pdo.view();
        assert!(!view.is_faulted());
    }

    // ── Homing ──

    #[test]
    fn test_view_ensure_homing_mode() {
        let mut pdo = TestPdo::default();
        let mut view = pdo.view();
        view.ensure_homing_mode();
        assert_eq!(*view.modes_of_operation, 6);
    }

    #[test]
    fn test_view_trigger_and_clear_homing() {
        let mut pdo = TestPdo::default();
        let mut view = pdo.view();
        view.cmd_enable_operation();

        // Bit 4 should be clear initially
        assert_eq!(*view.control_word & (1 << 4), 0);

        // Trigger homing — bit 4 set
        view.trigger_homing();
        assert!(*view.control_word & (1 << 4) != 0);
        // State machine bits preserved
        assert_eq!(*view.control_word & 0x000F, 0x000F);

        // Clear homing start — bit 4 clear
        view.clear_homing_start();
        assert_eq!(*view.control_word & (1 << 4), 0);
        assert_eq!(*view.control_word & 0x000F, 0x000F);
    }

    #[test]
    fn test_homing_progress_idle() {
        let mut pdo = TestPdo {
            // Bit 10 = 1, bit 12 = 0, bit 13 = 0 → Idle (not started)
            status_word: 0x0427, // OpEnabled + bit10
            ..Default::default()
        };
        let view = pdo.view();
        assert_eq!(view.homing_progress(), HomingProgress::Idle);
    }

    #[test]
    fn test_homing_progress_in_progress() {
        let mut pdo = TestPdo {
            // Bit 10 = 0, bit 12 = 0, bit 13 = 0 → In Progress
            status_word: 0x0027, // OpEnabled, bits 10/12/13 clear
            ..Default::default()
        };
        let view = pdo.view();
        assert_eq!(view.homing_progress(), HomingProgress::InProgress);
    }

    #[test]
    fn test_homing_progress_attained() {
        let mut pdo = TestPdo {
            // Bit 12 = 1, bit 10 = 0, bit 13 = 0 → Attained
            status_word: 0x1027,
            ..Default::default()
        };
        let view = pdo.view();
        assert_eq!(view.homing_progress(), HomingProgress::Attained);
    }

    #[test]
    fn test_homing_progress_complete() {
        let mut pdo = TestPdo {
            // Bit 12 = 1, bit 10 = 1, bit 13 = 0 → Complete
            status_word: 0x1427,
            ..Default::default()
        };
        let view = pdo.view();
        assert_eq!(view.homing_progress(), HomingProgress::Complete);
    }

    #[test]
    fn test_homing_progress_error() {
        let mut pdo = TestPdo {
            // Bit 13 = 1 → Error (regardless of other bits)
            status_word: 0x2027,
            ..Default::default()
        };
        let view = pdo.view();
        assert_eq!(view.homing_progress(), HomingProgress::Error);

        // Error + attained + reached → still Error
        pdo.status_word = 0x3427;
        let view = pdo.view();
        assert_eq!(view.homing_progress(), HomingProgress::Error);
    }

    #[test]
    fn test_homing_has_homed_persists_across_modes() {
        let mut pdo = TestPdo {
            // OpEnabled + bit8 (has_homed)
            status_word: 0x0127,
            modes_of_operation_display: 1, // PP mode
            ..Default::default()
        };
        let view = pdo.view();

        assert!(view.has_homed());
        assert_eq!(view.current_mode(), Some(ModesOfOperation::ProfilePosition));
    }

    // ── AxisView ──

    #[test]
    fn test_axis_view_impl() {
        let mut pdo = TestPdo {
            status_word: 0x0027,
            position_actual: 5000,
            velocity_actual: 1000,
            modes_of_operation_display: 1,
            ..Default::default()
        };
        let mut view = pdo.view();

        // AxisView reads
        assert_eq!(AxisView::status_word(&view), 0x0027);
        assert_eq!(AxisView::position_actual(&view), 5000);
        assert_eq!(AxisView::velocity_actual(&view), 1000);
        assert_eq!(AxisView::modes_of_operation_display(&view), 1);

        // AxisView writes
        AxisView::set_control_word(&mut view, 0x000F);
        assert_eq!(*view.control_word, 0x000F);
        AxisView::set_target_position(&mut view, 10_000);
        assert_eq!(*view.target_position, 10_000);
    }
}