//! 闭环集成测试：`EscBus` + 内存通道 + 一阶电机仿真。
//!
//! 全部可在任意平台（macOS / Linux / CI）运行，无需硬件。

#![allow(clippy::unwrap_used, clippy::expect_used)]

use std::time::Duration;

use dji_esc::{
    BusOptions, CanFrame, CanLink, EscBus, EscBusError, EscConfig, EscFeedback,
    encode_feedback_frame,
};
use dji_esc_sim::spawn_plant;
use motor_core::{Disable, EffortDrive, MotorFeedback, VelocityDrive, VelocityGains};
use tokio::sync::mpsc;
use tokio::task::JoinHandle;
use tokio::time::{MissedTickBehavior, interval, sleep, timeout};

/// 与 `PlantParams::gm3508` 增益精确匹配的速度环参数（ff = 16384 / 9254）。
fn tuned(esc_id: u8, direction: f32) -> EscConfig {
    let mut cfg = EscConfig::gm3508(format!("m{esc_id}"), esc_id, direction);
    cfg.kp = 8.0;
    cfg.ki = 2.0;
    cfg.kd = 0.0;
    cfg.feedforward = 16384.0 / 9254.0;
    cfg
}

/// 轮询直到条件满足或超时（毫秒，仿真时间）。
async fn wait_until(total_ms: u64, mut cond: impl FnMut() -> bool) -> bool {
    let mut waited = 0u64;
    while waited < total_ms {
        if cond() {
            return true;
        }
        sleep(Duration::from_millis(5)).await;
        waited += 5;
    }
    cond()
}

/// 与 [`wait_until`] 相同，但每次轮询都重新下发 `target_rpm`。
///
/// **命令是租约**：驱动在 [`BusOptions::command_timeout`]（默认 50ms）内未收到
/// 新命令就强制 0 输出。真实底盘循环每 1ms 重发一次，这里以 5ms 节拍模拟。
async fn hold_until<M: VelocityDrive>(
    total_ms: u64,
    motor: &M,
    target_rpm: f32,
    mut cond: impl FnMut() -> bool,
) -> bool {
    let mut waited = 0u64;
    loop {
        motor.set_velocity(target_rpm); // 续租
        if cond() {
            return true;
        }
        if waited >= total_ms {
            return false;
        }
        sleep(Duration::from_millis(5)).await;
        waited += 5;
    }
}

/// 保持 `target_rpm` 共 `ms` 毫秒（期间持续续租），仅推进仿真时间。
async fn hold<M: VelocityDrive>(motor: &M, target_rpm: f32, ms: u64) {
    let _ = hold_until(ms, motor, target_rpm, || false).await;
}

/// 手动向总线注入一帧所有电机的反馈（新鲜度 100ms 内有效）。
async fn send_feedback(peer: &CanLink, esc_ids: &[u8]) {
    for &id in esc_ids {
        let fb = EscFeedback { angle_raw: 0, speed_rpm: 0, current_raw: 0, temperature_c: 30 };
        peer.outgoing_tx.send(encode_feedback_frame(id, &fb)).await.unwrap();
    }
}

async fn recv_command(peer: &mut CanLink) -> CanFrame {
    timeout(Duration::from_millis(100), peer.incoming_rx.recv())
        .await
        .expect("timed out waiting for command frame")
        .expect("link closed")
}

fn slot_current(frame: &CanFrame, slot: usize) -> i16 {
    i16::from_be_bytes([frame.data[slot * 2], frame.data[slot * 2 + 1]])
}

// ---------------------------------------------------------------- 收敛性

#[tokio::test(start_paused = true)]
async fn velocity_loop_converges() {
    let (bus_link, plant_link) = CanLink::pair(512);
    let plant = spawn_plant(plant_link, &[1], Duration::from_millis(1));
    let bus = EscBus::spawn(bus_link, vec![tuned(1, 1.0)], BusOptions::default()).unwrap();
    let motor = bus.motor(1).unwrap().clone();

    motor.set_velocity(3000.0);
    let ok = hold_until(2000, &motor, 3000.0, || motor.state().rotor_speed_rpm >= 2950.0).await;
    assert!(ok, "not converged, rpm = {}", motor.state().rotor_speed_rpm);

    // 稳态保持（速度无漂移、反馈持续流入）；期间必须继续续租命令。
    let count_before = motor.state().feedback_count;
    hold(&motor, 3000.0, 300).await;
    let st = motor.state();
    assert!((2950.0..=3050.0).contains(&st.rotor_speed_rpm), "steady state drifted: {st:?}");
    assert!(
        st.feedback_count >= count_before + 280,
        "feedback should keep flowing: {} → {}",
        count_before,
        st.feedback_count
    );

    plant.abort();
    bus.shutdown().await;
}

#[tokio::test(start_paused = true)]
async fn reversed_motor_converges_in_physical_frame() {
    // direction = -1：物理 +2000 rpm ⇔ 电调侧 -2000 rpm。
    let (bus_link, plant_link) = CanLink::pair(512);
    let plant = spawn_plant(plant_link, &[2], Duration::from_millis(1));
    let bus = EscBus::spawn(bus_link, vec![tuned(2, -1.0)], BusOptions::default()).unwrap();
    let motor = bus.motor(2).unwrap().clone();

    motor.set_velocity(2000.0);
    let ok = hold_until(2000, &motor, 2000.0, || motor.state().rotor_speed_rpm >= 1950.0).await;
    assert!(ok, "not converged, rpm = {}", motor.state().rotor_speed_rpm);

    let st = motor.state();
    assert!((1950.0..=2050.0).contains(&st.rotor_speed_rpm), "{st:?}");
    // 物理转速为正 ⇒ 电调电流为负 ⇒ 物理电流 = dir × esc > 0。
    assert!(st.effort_raw > 0, "{st:?}");

    plant.abort();
    bus.shutdown().await;
}

// ---------------------------------------------------------------- 安全

#[tokio::test(start_paused = true)]
async fn motor_without_feedback_commands_zero_current() {
    let (bus_link, mut peer) = CanLink::pair(64);
    // 不接 plant → 永远没有反馈。
    let bus = EscBus::spawn(bus_link, vec![tuned(1, 1.0)], BusOptions::default()).unwrap();

    bus.motor(1).unwrap().set_velocity(5000.0);
    for _ in 0..5 {
        let frame = recv_command(&mut peer).await;
        assert_eq!(frame.id, 0x200);
        assert_eq!(frame.data, [0; 8], "must send zero current while offline");
    }
    bus.shutdown().await;
}

#[tokio::test(start_paused = true)]
async fn current_limit_clamps_saturation() {
    let (bus_link, mut peer) = CanLink::pair(64);
    let mut cfg = tuned(1, 1.0);
    cfg.current_limit = 5000;
    let bus = EscBus::spawn(bus_link, vec![cfg], BusOptions::default()).unwrap();

    send_feedback(&peer, &[1]).await;
    bus.motor(1).unwrap().set_velocity(30000.0); // 不可达目标 → 深度饱和
    sleep(Duration::from_millis(5)).await;

    let mut saw_saturated = false;
    for _ in 0..5 {
        bus.motor(1).unwrap().set_velocity(30000.0); // 续租，避免读到租约到期后的 0
        let frame = recv_command(&mut peer).await;
        let raw = slot_current(&frame, 0);
        assert!(raw <= 5000, "current {raw} exceeds limit 5000");
        saw_saturated |= raw == 5000;
    }
    assert!(saw_saturated, "loop should reach the configured limit");
    bus.shutdown().await;
}

// ---------------------------------------------------------------- 命令租约

/// 反馈喂食器：每 5ms 注入一帧所有电机的反馈，让电机保持"在线"，
/// 从而把「租约到期归零」与「离线保护归零」区分开。
fn spawn_feedback(yield_tx: mpsc::Sender<CanFrame>, esc_ids: Vec<u8>) -> JoinHandle<()> {
    tokio::spawn(async move {
        let mut ticker = interval(Duration::from_millis(5));
        ticker.set_missed_tick_behavior(MissedTickBehavior::Skip);
        let fb = EscFeedback { angle_raw: 0, speed_rpm: 0, current_raw: 0, temperature_c: 30 };
        loop {
            ticker.tick().await;
            for &id in &esc_ids {
                if yield_tx.send(encode_feedback_frame(id, &fb)).await.is_err() {
                    return;
                }
            }
        }
    })
}

/// 一次性 `set_velocity` 在租约内出力，租约到期后必须自动归零；
/// 重新下发又能恢复出力——这就是"命令是租约"契约的可执行规范。
#[tokio::test(start_paused = true)]
async fn command_lease_expires_and_renews() {
    let (bus_link, mut peer) = CanLink::pair(256);
    let feeder = spawn_feedback(peer.outgoing_tx.clone(), vec![1]);
    let bus = EscBus::spawn(bus_link, vec![tuned(1, 1.0)], BusOptions::default()).unwrap();
    let motor = bus.motor(1).unwrap().clone();

    // 1) 下发后 30ms 内（< 50ms 租约）应看到非零电流。
    motor.set_velocity(3000.0);
    let mut live = false;
    for _ in 0..30 {
        if slot_current(&recv_command(&mut peer).await, 0) != 0 {
            live = true;
            break;
        }
    }
    assert!(live, "租约内应输出非零电流");

    // 2) 沉默 200ms（> 50ms 租约）→ 必须强制归零。
    sleep(Duration::from_millis(200)).await;
    // 排空沉默期间积压的帧：其中前段仍带着租约到期前的旧命令。
    while peer.incoming_rx.try_recv().is_ok() {}
    sleep(Duration::from_millis(10)).await;
    for _ in 0..5 {
        let raw = slot_current(&recv_command(&mut peer).await, 0);
        assert_eq!(raw, 0, "租约到期后必须归零，实测 {raw}");
    }

    // 3) 续租 → 恢复出力。
    motor.set_velocity(3000.0);
    let mut renewed = false;
    for _ in 0..30 {
        if slot_current(&recv_command(&mut peer).await, 0) != 0 {
            renewed = true;
            break;
        }
    }
    assert!(renewed, "续租后应恢复非零电流");

    feeder.abort();
    bus.shutdown().await;
}

// ---------------------------------------------------------------- 组帧与路由

#[tokio::test(start_paused = true)]
async fn current_commands_route_to_group_slots() {
    let (bus_link, mut peer) = CanLink::pair(256);
    let configs = (1..=5).map(|id| tuned(id, 1.0)).collect();
    let bus = EscBus::spawn(bus_link, configs, BusOptions::default()).unwrap();

    bus.motor(3).unwrap().set_effort_raw(1234);
    bus.motor(5).unwrap().set_effort_raw(-567);
    send_feedback(&peer, &(1..=5).collect::<Vec<_>>()).await;
    sleep(Duration::from_millis(5)).await;

    let mut saw_200 = false;
    let mut saw_1ff = false;
    for _ in 0..20 {
        // 续租两条直发命令，避免读到租约到期后的 0 槽。
        bus.motor(3).unwrap().set_effort_raw(1234);
        bus.motor(5).unwrap().set_effort_raw(-567);
        let frame = recv_command(&mut peer).await;
        match frame.id {
            0x200 if !saw_200 => {
                assert_eq!(frame.data, [0, 0, 0, 0, 0x04, 0xD2, 0, 0], "esc3 slot = 1234");
                saw_200 = true;
            }
            0x1FF if !saw_1ff => {
                // -567 = 0xFDC9（i16 补码，大端）。
                assert_eq!(frame.data, [0xFD, 0xC9, 0, 0, 0, 0, 0, 0], "esc5 slot = -567");
                saw_1ff = true;
            }
            _ => {}
        }
        if saw_200 && saw_1ff {
            break;
        }
    }
    assert!(saw_200, "no 0x200 frame observed");
    assert!(saw_1ff, "no 0x1FF frame observed");

    // disable 后槽位清零。
    bus.motor(3).unwrap().disable();
    let zeroed = wait_until(200, || {
        try_find_frame(&mut peer, |frame| frame.id == 0x200 && slot_current(frame, 2) == 0)
    })
    .await;
    assert!(zeroed, "esc3 slot should return to 0 after disable");
    bus.shutdown().await;
}

/// 非阻塞地扫一眼通道里已有的帧。
fn try_find_frame(peer: &mut CanLink, pred: impl Fn(&CanFrame) -> bool) -> bool {
    while let Ok(frame) = peer.incoming_rx.try_recv() {
        if pred(&frame) {
            return true;
        }
    }
    false
}

// ---------------------------------------------------------------- 反馈 → 状态

#[tokio::test]
async fn feedback_updates_state_with_direction() {
    let (bus_link, peer) = CanLink::pair(64);
    let bus = EscBus::spawn(bus_link, vec![tuned(2, -1.0)], BusOptions::default()).unwrap();

    // 两帧正向跨圈：8000 → 100，电调侧圈数 ≈ 1.0122。
    let fb = EscFeedback { angle_raw: 8000, speed_rpm: 600, current_raw: -300, temperature_c: 47 };
    peer.outgoing_tx.send(encode_feedback_frame(2, &fb)).await.unwrap();
    let fb2 = EscFeedback { angle_raw: 100, ..fb };
    peer.outgoing_tx.send(encode_feedback_frame(2, &fb2)).await.unwrap();
    sleep(Duration::from_millis(50)).await;

    let st = bus.motor(2).unwrap().state();
    assert_eq!(st.rotor_angle_raw, 100);
    assert!((st.rotor_speed_rpm + 600.0).abs() < 1e-3); // direction = -1
    assert_eq!(st.effort_raw, 300);
    assert_eq!(st.temperature_c, 47);
    assert_eq!(st.feedback_count, 2);
    let esc_rev = 1.0 + 100.0 / 8192.0;
    assert!(
        (st.rotor_revolutions + esc_rev).abs() < 1e-3,
        "revolutions = {}",
        st.rotor_revolutions
    );
    // 输出轴换算由 `OutputShaft` 负责（见 motor-core gearbox 单测）。
    bus.shutdown().await;
}

// ---------------------------------------------------------------- 生命周期

#[tokio::test(start_paused = true)]
async fn shutdown_stops_tasks_and_closes_link() {
    let (bus_link, mut peer) = CanLink::pair(128);
    // 不接 plant，直接验证任务生命周期。
    let bus = EscBus::spawn(bus_link, vec![tuned(1, 1.0)], BusOptions::default()).unwrap();
    bus.motor(1).unwrap().set_velocity(1000.0);
    sleep(Duration::from_millis(20)).await;
    // 有命令帧在流动。
    assert!(peer.incoming_rx.recv().await.is_some());

    bus.shutdown().await;
    // 排空残留缓冲帧后应立即得到 None（发送端已全部退出）；
    // 若任务仍在运行，帧会持续流入并触发超时。
    loop {
        match timeout(Duration::from_millis(100), peer.incoming_rx.recv()).await {
            Ok(None) => break,
            Ok(Some(_)) => {} // 排空残留缓冲帧
            Err(elapsed) => panic!("bus tasks still running after shutdown (waited {elapsed:?})"),
        }
    }
}

#[test]
fn spawn_rejects_bad_configs() {
    let link = || CanLink::pair(8).0;
    assert_eq!(
        EscBus::spawn(link(), vec![], BusOptions::default()).err(),
        Some(EscBusError::NoMotors)
    );
    assert_eq!(
        EscBus::spawn(link(), vec![tuned(2, 1.0), tuned(2, -1.0)], BusOptions::default()).err(),
        Some(EscBusError::DuplicateEscId(2))
    );
    let mut bad = tuned(1, 1.0);
    bad.direction = 0.0;
    let err = EscBus::spawn(link(), vec![bad], BusOptions::default()).err();
    assert!(
        matches!(err, Some(EscBusError::InvalidConfig { .. })),
        "expected InvalidConfig, got {err:?}"
    );
}

// ---------------------------------------------------------------- 增益热更新

/// 自动整定的真机后端靠这条路径逐次试验：不重启总线，只换增益。
/// 契约：① 读取即得到最新增益；② 换增益后控制器**状态复位**（无旧积分残留）；
/// ③ 限幅等安全字段不受影响。
#[tokio::test(start_paused = true)]
async fn velocity_gains_can_be_hot_swapped() {
    let (bus_link, plant_link) = CanLink::pair(256);
    let plant = spawn_plant(plant_link, &[1], Duration::from_millis(1));
    let cfg = tuned(1, 1.0);
    let limit = i32::from(cfg.current_limit);
    let bus = EscBus::spawn(bus_link, vec![cfg.clone()], BusOptions::default()).unwrap();
    let motor = bus.motor(1).unwrap().clone();

    // ① 初始增益来自 EscConfig（含前馈）。
    assert_eq!(motor.velocity_gains(), cfg.velocity_gains());

    // 让旧增益的积分先积累起来（大静差 + 深度饱和）。
    motor.set_velocity(9000.0);
    hold(&motor, 9000.0, 200).await;
    let stale = motor.velocity_gains();

    // ② 热更新：控制器被重建。
    let swapped = VelocityGains::new(1.0, 0.0, 0.0, 0.0);
    motor.set_velocity_gains(swapped);
    assert_eq!(motor.velocity_gains(), swapped);
    assert_ne!(motor.velocity_gains(), stale);

    // 新增益生效：误差 e 时输出 = kp·e = e（无前馈、无积分），并仍被限幅夹住。
    motor.set_velocity(30_000.0);
    let saturated =
        hold_until(500, &motor, 30_000.0, || i32::from(motor.state().effort_raw) >= limit).await;
    assert!(saturated, "effort = {} 未达到限幅 {}", motor.state().effort_raw, limit);

    // ③ 限幅仍是启动时的 current_limit：热更新不得放宽安全边界。
    let effort = i32::from(motor.state().effort_raw);
    assert_eq!(effort, limit, "饱和值必须正好是 current_limit");
    assert_eq!(motor.velocity_gains(), swapped, "热更新后增益保持不变");

    plant.abort();
    bus.shutdown().await;
}