use stm32f4xx_hal::hal::digital::v2::OutputPin;
use smoltcp::time::Instant;
use crate::{
    ad7172,
    channel::{Channel, Channel0, Channel1},
    channel_state::ChannelState,
    pins,
    units::Volts,
};

pub const CHANNELS: usize = 2;

pub struct Channels {
    pub channel0: Channel<Channel0>,
    pub channel1: Channel<Channel1>,
    pub adc: ad7172::Adc<pins::AdcSpi, pins::AdcNss>,
    pub pwm: pins::PwmPins,
}

impl Channels {
    pub fn new(pins: pins::Pins) -> Self {
        let channel0 = Channel::new(pins.channel0);
        let channel1 = Channel::new(pins.channel1);
        let pwm = pins.pwm;

        let mut adc = ad7172::Adc::new(pins.adc_spi, pins.adc_nss).unwrap();
        // Feature not used
        adc.set_sync_enable(false).unwrap();
        // Setup channels
        adc.setup_channel(0, ad7172::Input::Ain0, ad7172::Input::Ain1).unwrap();
        adc.setup_channel(1, ad7172::Input::Ain2, ad7172::Input::Ain3).unwrap();
        adc.calibrate_offset().unwrap();

        Channels { channel0, channel1, adc, pwm }
    }

    pub fn channel_state<I: Into<usize>>(&mut self, channel: I) -> &mut ChannelState {
        match channel.into() {
            0 => &mut self.channel0.state,
            1 => &mut self.channel1.state,
            _ => unreachable!(),
        }
    }

    /// ADC input + PID processing
    pub fn poll_adc(&mut self, instant: Instant) -> Option<u8> {
        self.adc.data_ready().unwrap().map(|channel| {
            let data = self.adc.read_data().unwrap();

            let dac_value = {
                let state = self.channel_state(channel);
                let pid_output = state.update_pid(instant, data);

                if state.pid_engaged {
                    Some(pid_output)
                } else {
                    None
                }
            };
            if let Some(dac_value) = dac_value {
                // Forward PID output to i_set DAC
                self.set_dac(channel.into(), dac_value);
            }

            channel
        })
    }

    /// i_set DAC
    pub fn set_dac(&mut self, channel: usize, duty: u32) {
        match channel {
            0 => {
                self.channel0.dac.set(duty).unwrap();
                self.channel0.state.dac_value = duty;
                self.channel0.shdn.set_high().unwrap();
            }
            1 => {
                self.channel1.dac.set(duty).unwrap();
                self.channel1.state.dac_value = duty;
                self.channel1.shdn.set_high().unwrap();
            }
            _ => unreachable!(),
        }
    }

    pub fn read_dac_loopback(&mut self, channel: usize) -> Volts {
        match channel {
            0 => {
                let sample = self.channel0.adc.convert(
                    &self.channel0.dac_loopback_pin,
                    stm32f4xx_hal::adc::config::SampleTime::Cycles_480
                );
                let mv = self.channel0.adc.sample_to_millivolts(sample);
                Volts(mv as f64 / 1000.0)
            }
            1 => {
                let sample = self.channel1.adc.convert(
                    &self.channel1.dac_loopback_pin,
                    stm32f4xx_hal::adc::config::SampleTime::Cycles_480
                );
                let mv = self.channel1.adc.sample_to_millivolts(sample);
                Volts(mv as f64 / 1000.0)
            }
            _ => unreachable!(),
        }
    }

    pub fn read_itec(&mut self, channel: usize) -> Volts {
        match channel {
            0 => {
                let sample = self.channel0.adc.convert(
                    &self.channel0.itec_pin,
                    stm32f4xx_hal::adc::config::SampleTime::Cycles_480
                );
                let mv = self.channel0.adc.sample_to_millivolts(sample);
                Volts(mv as f64 / 1000.0)
            }
            1 => {
                let sample = self.channel1.adc.convert(
                    &self.channel1.itec_pin,
                    stm32f4xx_hal::adc::config::SampleTime::Cycles_480
                );
                let mv = self.channel1.adc.sample_to_millivolts(sample);
                Volts(mv as f64 / 1000.0)
            }
            _ => unreachable!(),
        }
    }
}