use std::pin::Pin;
use std::sync::{Arc, Mutex};
use std::time::Duration;

use async_trait::async_trait;
use futures::stream::{self, Stream};
use futures::StreamExt;

use crate::ble::source::SensorSource;
use crate::ble::BleError;
use crate::commands::Command;
use crate::device::{get_device_types, Device, DeviceType};
use crate::telemetry::Telemetry;

/// Виртуальный источник: scripted-поток, без реального BLE.
pub(crate) struct MockSource {
    devices: Vec<Device>,
    commands: Arc<Mutex<Vec<Command>>>,
}

impl MockSource {
    pub(crate) fn new() -> Self {
        let devices = vec![
            Device {
                id: "mock-hr".into(),
                address: "00:00:00:00:00:01".into(),
                display_name: Some("Mock HR".into()),
                rssi: Some(-45),
                service_uuids: vec!["0000180d-0000-1000-8000-00805f9b34fb".into()],
                characteristics: vec!["180d::2a37".into()],
                manufacturer_data: None,
                metadata: None,
            },
            Device {
                id: "mock-cad".into(),
                address: "00:00:00:00:00:02".into(),
                display_name: Some("Mock Cadence".into()),
                rssi: Some(-50),
                service_uuids: vec!["00001816-0000-1000-8000-00805f9b34fb".into()],
                characteristics: vec!["1816::2a5b".into()],
                manufacturer_data: None,
                metadata: None,
            },
            Device {
                id: "mock-trainer".into(),
                address: "00:00:00:00:00:03".into(),
                display_name: Some("Mock Trainer".into()),
                rssi: Some(-55),
                service_uuids: vec!["00001826-0000-1000-8000-00805f9b34fb".into()],
                characteristics: vec!["1826::2ad2".into()],
                manufacturer_data: None,
                metadata: None,
            },
        ];
        Self {
            devices,
            commands: Arc::new(Mutex::new(Vec::new())),
        }
    }

    /// Записанные команды — читаются только в тестах движка воркаута.
    #[allow(dead_code)]
    pub(crate) fn commands(&self) -> Vec<Command> {
        self.commands.lock().unwrap().clone()
    }
}

#[async_trait]
impl SensorSource for MockSource {
    async fn scan(&self, _seconds: u64) -> Result<Vec<Device>, BleError> {
        Ok(self.devices.clone())
    }

    async fn stream(&self, device: &Device)
        -> Result<Pin<Box<dyn Stream<Item = Telemetry> + Send>>, BleError>
    {
        let types = get_device_types(device);
        let s: Pin<Box<dyn Stream<Item = Telemetry> + Send>> = if types.contains(&DeviceType::Trainer) {
            // мощность 150..300 Вт + каденс 85..95 rpm (как FTMS 0x2AD2 — оба поля)
            stream::unfold(0u16, |i| async move {
                tokio::time::sleep(Duration::from_millis(250)).await;
                let item = if i % 2 == 0 {
                    let watts = 150 + ((i / 2 % 16) * 10) as i16;
                    Telemetry::Power { watts }
                } else {
                    let rpm = 85.0 + (i / 2 % 10) as f32;
                    Telemetry::Cadence { rpm }
                };
                Some((item, i.wrapping_add(1)))
            })
            .boxed()
        } else if types.contains(&DeviceType::CadSensor) {
            // каденс 85..95 rpm
            stream::unfold(0u16, |i| async move {
                tokio::time::sleep(Duration::from_millis(500)).await;
                let rpm = 85.0 + (i % 10) as f32;
                Some((Telemetry::Cadence { rpm }, i.wrapping_add(1)))
            })
            .boxed()
        } else {
            // пульс 120..169
            stream::unfold(0u16, |i| async move {
                tokio::time::sleep(Duration::from_millis(1000)).await;
                let bpm = 120 + (i % 50);
                Some((Telemetry::HeartRate { bpm }, i.wrapping_add(1)))
            })
            .boxed()
        };
        Ok(s)
    }

    async fn command(&self, _device: &Device, cmd: Command) -> Result<(), BleError> {
        self.commands.lock().unwrap().push(cmd);
        Ok(())
    }

    async fn request_control(&self, _device: &Device) -> Result<(), BleError> {
        Ok(())
    }

    async fn battery(&self, device: &Device) -> Result<u8, BleError> {
        let percent = match device.id.as_str() {
            "mock-hr" => 15,
            "mock-cad" => 60,
            "mock-trainer" => 85,
            _ => 100,
        };
        Ok(percent)
    }
}

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

    #[tokio::test]
    async fn test_mock_scan_returns_three_devices() {
        let src = MockSource::new();
        let devices = src.scan(0).await.unwrap();
        assert_eq!(devices.len(), 3);
    }

    #[tokio::test]
    async fn test_mock_stream_yields_telemetry() {
        let src = MockSource::new();
        let devices = src.scan(0).await.unwrap();
        let hr = devices.iter().find(|d| d.id == "mock-hr").unwrap();
        let mut stream = src.stream(hr).await.unwrap();
        let first = stream.next().await;
        assert!(matches!(first, Some(Telemetry::HeartRate { .. })));
    }

    #[tokio::test]
    async fn test_mock_trainer_emits_power_and_cadence() {
        let src = MockSource::new();
        let devices = src.scan(0).await.unwrap();
        let trainer = devices.iter().find(|d| d.id == "mock-trainer").unwrap();
        let mut stream = src.stream(trainer).await.unwrap();
        let mut saw_power = false;
        let mut saw_cadence = false;
        for _ in 0..8 {
            match stream.next().await {
                Some(Telemetry::Power { .. }) => saw_power = true,
                Some(Telemetry::Cadence { .. }) => saw_cadence = true,
                _ => {}
            }
        }
        assert!(saw_power, "тренер должен эмитить мощность");
        assert!(saw_cadence, "тренер должен эмитить каденс");
    }
}