use std::{
    sync::{Arc, Mutex},
    thread::{sleep, spawn},
    time::Duration,
};

use embedded_hal::{adc::Channel, prelude::_embedded_hal_adc_OneShot};
use embedded_svc::event_bus::Postbox;
use esp_idf_hal::{
    adc::{
        config::{self},
        Analog, Atten6dB, PoweredAdc, ADC1,
    },
    gpio::{Gpio1, Gpio2, Gpio3, Input},
};
use esp_idf_svc::eventloop::{
    Background, EspBackgroundEventLoop, EspEventFetchData, EspEventLoop, EspEventPostData,
    EspTypedEventDeserializer, EspTypedEventSerializer, EspTypedEventSource,
};
use esp_idf_sys::c_types;
use log::{debug, warn};
use serde::{Deserialize, Serialize};

use crate::time::Time;

pub static mut VOLTAGE_EVENTLOOP: Option<EspEventLoop<esp_idf_svc::eventloop::User<Background>>> =
    None;

const ADAPTER_OFFSET: f32 = 12002f32 / 900f32;
const BATTERY_OFFSET: f32 = 12002f32 / 900f32;
const OUTPUT_OFFSET: f32 = 12002f32 / 900f32;

pub struct VoltageDetection {
    pub worker: VoltageDetectionWorker,
}

#[derive(Clone, Copy, Serialize, Deserialize)]
pub struct VoltageDetectionWorker {
    pub adapter_voltage: u16,
    pub battery_voltage: u16,
    pub output_voltage: u16,
}

impl VoltageDetection {
    pub fn new() -> anyhow::Result<Self> {
        return anyhow::Ok(Self {
            worker: VoltageDetectionWorker::new(),
        });
    }

    pub fn watching(&mut self) -> anyhow::Result<()> {
        match EspBackgroundEventLoop::new(&Default::default()) {
            Ok(eventloop) => unsafe { VOLTAGE_EVENTLOOP = Some(eventloop) },
            Err(err) => anyhow::bail!("Init Event Loop failed. {:?}", err),
        }
        let worker = Arc::new(Mutex::new(self.worker));

        spawn(move || {
            let handler = || -> anyhow::Result<()> {
                let mut adapter_pin = unsafe { Gpio1::<Input>::new() }
                    .into_analog_atten_6db()
                    .map_err(|err| {
                        anyhow::anyhow!("Failed to set GPIO 1 as analog input. {}", err)
                    })?;
                let mut battery_pin = unsafe { Gpio2::<Input>::new() }
                    .into_analog_atten_6db()
                    .map_err(|err| {
                        anyhow::anyhow!("Failed to set GPIO 2 as analog input. {}", err)
                    })?;
                let mut output_pin = unsafe { Gpio3::<Input>::new() }
                    .into_analog_atten_6db()
                    .map_err(|err| {
                        anyhow::anyhow!("Failed to set GPIO 3 as analog input. {}", err)
                    })?;

                let mut adc = PoweredAdc::new(unsafe { ADC1::new() }, config::Config::new())?;

                let mut worker = worker.lock().map_err(|err| {
                    anyhow::anyhow!("Lock VoltageDetection Worker Failed. {}", err)
                })?;

                let mut last_runing_at;

                loop {
                    last_runing_at = Time::new().get_time();
                    match worker.read_once(
                        &mut adc,
                        &mut adapter_pin,
                        &mut battery_pin,
                        &mut output_pin,
                    ) {
                        Ok(_) => debug!(
                            "Adapter: {},\tBattery: {},\t Output: {}",
                            worker.adapter_voltage, worker.battery_voltage, worker.output_voltage
                        ),
                        Err(err) => warn!("Read Failed. {}", err),
                    }

                    if let Some(eventloop) = unsafe { VOLTAGE_EVENTLOOP.as_mut() } {
                        if let Err(err) = eventloop.post(
                            &mut VoltageDetectionWorker {
                                adapter_voltage: worker.adapter_voltage,
                                battery_voltage: worker.battery_voltage,
                                output_voltage: worker.output_voltage,
                            },
                            None,
                        ) {
                            warn!("Post Result to Event Loop failed. {}", err);
                        }
                    } else {
                        warn!("EVENTLOOP IS NONE");
                    }
                    let mut delta = Time::new().get_time() - last_runing_at;

                    if delta >= Duration::from_millis(5000) {
                        delta = Duration::ZERO
                    }

                    sleep(Duration::from_millis(5000) - delta);
                }
            };

            if let Err(err) = handler() {
                warn!("init failed. {}", err)
            }
        });
        return anyhow::Ok(());
    }
}

impl VoltageDetectionWorker {
    pub fn new() -> Self {
        return Self {
            adapter_voltage: 0,
            battery_voltage: 0,
            output_voltage: 0,
        };
    }

    pub fn read_once(
        &mut self,
        adc: &mut PoweredAdc<ADC1>,
        adapter_pin: &mut Gpio1<Atten6dB<ADC1>>,
        battery_pin: &mut Gpio2<Atten6dB<ADC1>>,
        output_pin: &mut Gpio3<Atten6dB<ADC1>>,
    ) -> anyhow::Result<()> {
        match self.read_pin_once(adc, adapter_pin) {
            Ok(voltage) => {
                self.adapter_voltage = ((voltage as f32) * ADAPTER_OFFSET) as u16;
            }
            Err(err) => {
                warn!("Adapter Voltage read failed: {:?}", err);
            }
        }

        match self.read_pin_once(adc, battery_pin) {
            Ok(voltage) => {
                self.battery_voltage = ((voltage as f32) * BATTERY_OFFSET) as u16;
            }
            Err(err) => {
                warn!("Adapter Voltage read failed: {:?}", err);
            }
        }
        match self.read_pin_once(adc, output_pin) {
            Ok(voltage) => {
                self.output_voltage = ((voltage as f32) * OUTPUT_OFFSET) as u16;
            }
            Err(err) => {
                warn!("Adapter Voltage read failed: {:?}", err);
            }
        }

        return anyhow::Ok(());
    }
    pub fn read_pin_once<AN: Analog<ADC1>, PIN: Channel<AN, ID = u8>>(
        &mut self,
        adc: &mut PoweredAdc<ADC1>,
        pin: &mut PIN,
    ) -> anyhow::Result<u16> {
        let mut avg_voltage: u16 = 0;
        for _ in 0..10 {
            let voltage = adc.read(pin);
            match voltage {
                Ok(voltage) => {
                    avg_voltage += voltage;
                }
                Err(err) => {
                    anyhow::bail!("Adapter Voltage read failed: {:?}", err)
                }
            };
            sleep(Duration::from_millis(100));
        }
        anyhow::Ok(avg_voltage / 10)
    }
}

impl EspTypedEventSource for VoltageDetectionWorker {
    fn source() -> *const c_types::c_char {
        b"VOLTAGES\0".as_ptr() as *const _
    }
}

impl EspTypedEventSerializer<VoltageDetectionWorker> for VoltageDetectionWorker {
    fn serialize<R>(
        event: &VoltageDetectionWorker,
        f: impl for<'a> FnOnce(&'a EspEventPostData) -> R,
    ) -> R {
        f(&unsafe { EspEventPostData::new(Self::source(), Self::event_id(), event) })
    }
}

impl EspTypedEventDeserializer<VoltageDetectionWorker> for VoltageDetectionWorker {
    fn deserialize<R>(
        data: &EspEventFetchData,
        f: &mut impl for<'a> FnMut(&'a VoltageDetectionWorker) -> R,
    ) -> R {
        f(unsafe { data.as_payload() })
    }
}