#![deny(warnings)]
#![allow(clippy::missing_safety_doc)]
#![no_std]
#![no_main]
#![cfg_attr(feature = "nightly", feature(asm))]
// Enable returning `!`
#![cfg_attr(feature = "nightly", feature(never_type))]
#![cfg_attr(feature = "nightly", feature(core_intrinsics))]

#[inline(never)]
#[panic_handler]
#[cfg(all(feature = "nightly", not(feature = "semihosting")))]
fn panic(_info: &core::panic::PanicInfo) -> ! {
    let gpiod = unsafe { &*hal::stm32::GPIOD::ptr() };
    gpiod.odr.modify(|_, w| w.odr6().high().odr12().high()); // FP_LED_1, FP_LED_3
    unsafe {
        core::intrinsics::abort();
    }
}

#[cfg(feature = "semihosting")]
extern crate panic_semihosting;

#[cfg(not(any(feature = "nightly", feature = "semihosting")))]
extern crate panic_halt;

#[macro_use]
extern crate log;

// use core::sync::atomic::{AtomicU32, AtomicBool, Ordering};
use rtfm::cyccnt::{Instant, U32Ext};
use cortex_m_rt::exception;
use cortex_m;
use stm32h7xx_hal as hal;
use stm32h7xx_hal::{
    prelude::*,
};

use embedded_hal::{
    digital::v2::OutputPin,
};

use stm32h7_ethernet as ethernet;
use smoltcp as net;

use heapless::{
    String,
    consts::*,
};

#[link_section = ".sram3.eth"]
static mut DES_RING: ethernet::DesRing = ethernet::DesRing::new();

mod afe;
mod eeprom;
mod iir;
mod server;

#[cfg(not(feature = "semihosting"))]
fn init_log() {}

#[cfg(feature = "semihosting")]
fn init_log() {
    use cortex_m_log::log::{init as init_log, Logger};
    use cortex_m_log::printer::semihosting::{hio::HStdout, InterruptOk};
    use log::LevelFilter;
    static mut LOGGER: Option<Logger<InterruptOk<HStdout>>> = None;
    let logger = Logger {
        inner: InterruptOk::<_>::stdout().unwrap(),
        level: LevelFilter::Info,
    };
    let logger = unsafe { LOGGER.get_or_insert(logger) };

    init_log(logger).unwrap();
}

// Pull in build information (from `built` crate)
mod build_info {
    #![allow(dead_code)]
    // include!(concat!(env!("OUT_DIR"), "/built.rs"));
}

pub struct NetStorage {
    ip_addrs: [net::wire::IpCidr; 1],
    neighbor_cache: [Option<(net::wire::IpAddress, net::iface::Neighbor)>; 8],
}

static mut NET_STORE: NetStorage = NetStorage {
    // Placeholder for the real IP address, which is initialized at runtime.
    ip_addrs: [net::wire::IpCidr::Ipv6(net::wire::Ipv6Cidr::SOLICITED_NODE_PREFIX)],

    neighbor_cache: [None; 8],
};

const SCALE: f32 = ((1 << 15) - 1) as f32;

const SPI_START_CODE: u32 = 0x201;

// static ETHERNET_PENDING: AtomicBool = AtomicBool::new(true);

const TCP_RX_BUFFER_SIZE: usize = 8192;
const TCP_TX_BUFFER_SIZE: usize = 8192;

type AFE1 = afe::ProgrammableGainAmplifier<
    hal::gpio::gpiof::PF2<hal::gpio::Output<hal::gpio::PushPull>>,
    hal::gpio::gpiof::PF5<hal::gpio::Output<hal::gpio::PushPull>>>;

type AFE2 = afe::ProgrammableGainAmplifier<
    hal::gpio::gpiod::PD14<hal::gpio::Output<hal::gpio::PushPull>>,
    hal::gpio::gpiod::PD15<hal::gpio::Output<hal::gpio::PushPull>>>;

macro_rules! route_request {
    ($request:ident,
            readable_attributes: [$(($read_attribute:tt, $getter:tt)),*],
            modifiable_attributes: [$(($write_attribute:tt, $TYPE:ty, $setter:tt)),*]) => {
        match $request.req {
            server::AccessRequest::Read => {
                match $request.attribute {
                $(
                    $read_attribute => {
                        let value = match $getter() {
                            Ok(data) => data,
                            Err(_) => return server::Response::error($request.attribute,
                                                                     "Failed to set attribute"),
                        };

                        let encoded_data: String<U128> = match serde_json_core::to_string(&value) {
                            Ok(data) => data,
                            Err(_) => return server::Response::error($request.attribute,
                                    "Failed to encode attribute value"),
                        };

                        // Encoding data into a string surrounds it with qutotations. Because this
                        // value is then serialzed into another string, we remove the double
                        // quotations because they cannot be properly escaped.
                        server::Response::success($request.attribute,
                                &encoded_data[1..encoded_data.len()-1])
                    },
                 )*
                    _ => server::Response::error($request.attribute, "Unknown attribute")
                }
            },
            server::AccessRequest::Write => {
                match $request.attribute {
                $(
                    $write_attribute => {
                        // To avoid sending double quotations in the request, they are eliminated on
                        // the sender side. However, to properly deserialize the data, quotes need
                        // to be added back.
                        let mut value: String<U128> = String::new();
                        value.push('"').unwrap();
                        value.push_str($request.value).unwrap();
                        value.push('"').unwrap();

                        let new_value = match serde_json_core::from_str::<$TYPE>(value.as_str()) {
                            Ok(data) => data,
                            Err(_) => return server::Response::error($request.attribute,
                                    "Failed to decode value"),
                        };

                        match $setter(new_value) {
                            Ok(_) => server::Response::success($request.attribute, $request.value),
                            Err(_) => server::Response::error($request.attribute,
                                    "Failed to set attribute"),
                        }
                    }
                 )*
                    _ => server::Response::error($request.attribute, "Unknown attribute")
                }
            }
        }
    }
}

#[rtfm::app(device = stm32h7xx_hal::stm32, peripherals = true, monotonic = rtfm::cyccnt::CYCCNT)]
const APP: () = {
    struct Resources {
        adc1: hal::spi::Spi<hal::stm32::SPI2>,
        dac1: hal::spi::Spi<hal::stm32::SPI4>,
        afe1: AFE1,

        adc2: hal::spi::Spi<hal::stm32::SPI3>,
        dac2: hal::spi::Spi<hal::stm32::SPI5>,
        afe2: AFE2,

        eeprom_i2c: hal::i2c::I2c<hal::stm32::I2C2>,

        timer: hal::timer::Timer<hal::stm32::TIM2>,
        net_interface: net::iface::EthernetInterface<'static, 'static, 'static,
                                                     ethernet::EthernetDMA<'static>>,
        eth_mac: ethernet::EthernetMAC,
        mac_addr: net::wire::EthernetAddress,

        #[init([[0.; 5]; 2])]
        iir_state: [iir::IIRState; 2],
        #[init([iir::IIR { ba: [1., 0., 0., 0., 0.], y_offset: 0., y_min: -SCALE - 1., y_max: SCALE }; 2])]
        iir_ch: [iir::IIR; 2],
    }

    #[init]
    fn init(c: init::Context) -> init::LateResources {
        let dp = c.device;
        let mut cp = cortex_m::Peripherals::take().unwrap();

        let pwr = dp.PWR.constrain();
        let vos = pwr.freeze();

        let rcc = dp.RCC.constrain();
        let mut clocks = rcc
            //TODO: Re-enable HSE for Stabilizer platform.
//            .use_hse(8.mhz())
            .sysclk(400.mhz())
            .hclk(200.mhz())
            .per_ck(100.mhz())
            .pll2_p_ck(100.mhz())
            .pll2_q_ck(100.mhz())
            .freeze(vos, &dp.SYSCFG);

        // Enable SRAM3 for the ethernet descriptor ring.
        clocks.rb.ahb2enr.modify(|_, w| w.sram3en().set_bit());

        clocks.rb.rsr.write(|w| w.rmvf().set_bit());

        clocks.rb.d2ccip1r.modify(|_, w| w.spi123sel().pll2_p().spi45sel().pll2_q());

        let mut delay = hal::delay::Delay::new(cp.SYST, clocks.clocks);

        let gpioa = dp.GPIOA.split(&mut clocks);
        let gpiob = dp.GPIOB.split(&mut clocks);
        let gpioc = dp.GPIOC.split(&mut clocks);
        let gpiod = dp.GPIOD.split(&mut clocks);
        let gpioe = dp.GPIOE.split(&mut clocks);
        let gpiof = dp.GPIOF.split(&mut clocks);
        let gpiog = dp.GPIOG.split(&mut clocks);

        let afe1 = {
            let a0_pin = gpiof.pf2.into_push_pull_output();
            let a1_pin = gpiof.pf5.into_push_pull_output();
            afe::ProgrammableGainAmplifier::new(a0_pin, a1_pin)
        };

        let afe2 = {
            let a0_pin = gpiod.pd14.into_push_pull_output();
            let a1_pin = gpiod.pd15.into_push_pull_output();
            afe::ProgrammableGainAmplifier::new(a0_pin, a1_pin)
        };

        // Configure the SPI interfaces to the ADCs and DACs.
        let adc1_spi = {
            let spi_miso = gpiob.pb14.into_alternate_af5().set_speed(hal::gpio::Speed::VeryHigh);
            let spi_sck = gpiob.pb10.into_alternate_af5().set_speed(hal::gpio::Speed::VeryHigh);
            let _spi_nss = gpiob.pb9.into_alternate_af5();

            let config = hal::spi::Config::new(hal::spi::Mode{
                    polarity: hal::spi::Polarity::IdleHigh,
                    phase: hal::spi::Phase::CaptureOnSecondTransition,
                })
                .communication_mode(hal::spi::CommunicationMode::Receiver)
                .manage_cs()
                .transfer_size(1)
                .frame_size(16)
                .cs_delay(220e-9);

            let mut spi = dp.SPI2.spi(
                    (spi_sck, spi_miso, hal::spi::NoMosi),
                    config,
                    50.mhz(),
                    &clocks);

            spi.listen(hal::spi::Event::Eot);

            spi
        };

        let adc2_spi = {
            let spi_miso = gpiob.pb4.into_alternate_af6().set_speed(hal::gpio::Speed::VeryHigh);
            let spi_sck = gpioc.pc10.into_alternate_af6().set_speed(hal::gpio::Speed::VeryHigh);
            let _spi_nss = gpioa.pa15.into_alternate_af6();


            let config = hal::spi::Config::new(hal::spi::Mode{
                    polarity: hal::spi::Polarity::IdleHigh,
                    phase: hal::spi::Phase::CaptureOnSecondTransition,
                })
                .communication_mode(hal::spi::CommunicationMode::Receiver)
                .manage_cs()
                .transfer_size(1)
                .frame_size(16)
                .cs_delay(220e-9);

            let mut spi = dp.SPI3.spi(
                    (spi_sck, spi_miso, hal::spi::NoMosi),
                    config,
                    50.mhz(),
                    &clocks);

            spi.listen(hal::spi::Event::Eot);

            spi
        };

        let dac1_spi = {
            let spi_miso = gpioe.pe5.into_alternate_af5().set_speed(hal::gpio::Speed::VeryHigh);
            let spi_sck = gpioe.pe2.into_alternate_af5().set_speed(hal::gpio::Speed::VeryHigh);
            let _spi_nss = gpioe.pe4.into_alternate_af5();

            let config = hal::spi::Config::new(hal::spi::Mode{
                    polarity: hal::spi::Polarity::IdleHigh,
                    phase: hal::spi::Phase::CaptureOnSecondTransition,
                })
                .communication_mode(hal::spi::CommunicationMode::Transmitter)
                .manage_cs()
                .transfer_size(1)
                .frame_size(16)
                .swap_mosi_miso();

            let spi = dp.SPI4.spi((spi_sck, spi_miso, hal::spi::NoMosi), config, 50.mhz(), &clocks);
            spi
        };

        let dac2_spi = {
            let spi_miso = gpiof.pf8.into_alternate_af5().set_speed(hal::gpio::Speed::VeryHigh);
            let spi_sck = gpiof.pf7.into_alternate_af5().set_speed(hal::gpio::Speed::VeryHigh);
            let _spi_nss = gpiof.pf6.into_alternate_af5();

            let config = hal::spi::Config::new(hal::spi::Mode{
                    polarity: hal::spi::Polarity::IdleHigh,
                    phase: hal::spi::Phase::CaptureOnSecondTransition,
                })
                .communication_mode(hal::spi::CommunicationMode::Transmitter)
                .manage_cs()
                .transfer_size(1)
                .frame_size(16)
                .swap_mosi_miso();

            let spi = dp.SPI5.spi((spi_sck, spi_miso, hal::spi::NoMosi), config, 50.mhz(), &clocks);

            spi
        };

        let mut fp_led_0 = gpiod.pd5.into_push_pull_output();
        let mut fp_led_1 = gpiod.pd6.into_push_pull_output();
        let mut fp_led_2 = gpiog.pg4.into_push_pull_output();
        let mut fp_led_3 = gpiod.pd12.into_push_pull_output();

        fp_led_0.set_low().unwrap();
        fp_led_1.set_low().unwrap();
        fp_led_2.set_low().unwrap();
        fp_led_3.set_low().unwrap();

        let mut eeprom_i2c = {
            let sda = gpiof.pf0.into_alternate_af4().set_open_drain();
            let scl = gpiof.pf1.into_alternate_af4().set_open_drain();
            dp.I2C2.i2c((scl, sda), 100.khz(), &clocks)
        };

        // Configure ethernet pins.
        {
            // Reset the PHY before configuring pins.
            let mut eth_phy_nrst = gpioe.pe3.into_push_pull_output();
            eth_phy_nrst.set_low().unwrap();
            delay.delay_us(200u8);
            eth_phy_nrst.set_high().unwrap();
            let _rmii_ref_clk = gpioa.pa1.into_alternate_af11().set_speed(hal::gpio::Speed::VeryHigh);
            let _rmii_mdio = gpioa.pa2.into_alternate_af11().set_speed(hal::gpio::Speed::VeryHigh);
            let _rmii_mdc = gpioc.pc1.into_alternate_af11().set_speed(hal::gpio::Speed::VeryHigh);
            let _rmii_crs_dv = gpioa.pa7.into_alternate_af11().set_speed(hal::gpio::Speed::VeryHigh);
            let _rmii_rxd0 = gpioc.pc4.into_alternate_af11().set_speed(hal::gpio::Speed::VeryHigh);
            let _rmii_rxd1 = gpioc.pc5.into_alternate_af11().set_speed(hal::gpio::Speed::VeryHigh);
            let _rmii_tx_en = gpiob.pb11.into_alternate_af11().set_speed(hal::gpio::Speed::VeryHigh);
            let _rmii_txd0 = gpiob.pb12.into_alternate_af11().set_speed(hal::gpio::Speed::VeryHigh);
            let _rmii_txd1 = gpiog.pg14.into_alternate_af11().set_speed(hal::gpio::Speed::VeryHigh);
        }

        let mac_addr = match eeprom::read_eui48(&mut eeprom_i2c) {
            Err(_) => {
                info!("Could not read EEPROM, using default MAC address");
                net::wire::EthernetAddress([0x10, 0xE2, 0xD5, 0x00, 0x03, 0x00])
            }
            Ok(raw_mac) => net::wire::EthernetAddress(raw_mac),
        };

        let (network_interface, eth_mac) = {
            // Configure the ethernet controller
            let (eth_dma, eth_mac) = unsafe {
                ethernet::ethernet_init(
                        dp.ETHERNET_MAC,
                        dp.ETHERNET_MTL,
                        dp.ETHERNET_DMA,
                        &mut DES_RING,
                        mac_addr.clone())
            };

            unsafe { ethernet::enable_interrupt() };

            let store = unsafe { &mut NET_STORE };

            store.ip_addrs[0] = net::wire::IpCidr::new(net::wire::IpAddress::v4(10, 0, 16, 99), 24);

            let neighbor_cache = net::iface::NeighborCache::new(&mut store.neighbor_cache[..]);

            let interface = net::iface::EthernetInterfaceBuilder::new(eth_dma)
                    .ethernet_addr(mac_addr)
                    .neighbor_cache(neighbor_cache)
                    .ip_addrs(&mut store.ip_addrs[..])
                    .finalize();

            (interface, eth_mac)
        };

        cp.SCB.enable_icache();

        // info!("Version {} {}", build_info::PKG_VERSION, build_info::GIT_VERSION.unwrap());
        // info!("Built on {}", build_info::BUILT_TIME_UTC);
        // info!("{} {}", build_info::RUSTC_VERSION, build_info::TARGET);

        // Utilize the cycle counter for RTFM scheduling.
        cp.DWT.enable_cycle_counter();

        let mut dma = hal::dma::Dma::dma(dp.DMA1, dp.DMAMUX1, &clocks);
        dma.configure_m2p_stream(hal::dma::Stream::One,
                             &SPI_START_CODE as *const _ as u32,
                             &adc1_spi.spi.cr1 as *const _ as u32,
                             hal::dma::DMAREQ_ID::TIM2_CH1);

        dma.configure_m2p_stream(hal::dma::Stream::Two,
                             &SPI_START_CODE as *const _ as u32,
                             &adc2_spi.spi.cr1 as *const _ as u32,
                             hal::dma::DMAREQ_ID::TIM2_CH2);

        // Configure timer 2 to trigger conversions for the ADC
        let mut timer2 = dp.TIM2.timer(500.khz(), &mut clocks);
        timer2.configure_channel(hal::timer::Channel::One, 0.25);
        timer2.configure_channel(hal::timer::Channel::Two, 0.75);

        timer2.listen(hal::timer::Event::ChannelOneDma);
        timer2.listen(hal::timer::Event::ChannelTwoDma);

        init::LateResources {
            adc1: adc1_spi,
            dac1: dac1_spi,
            adc2: adc2_spi,
            dac2: dac2_spi,
            afe1: afe1,
            afe2: afe2,

            timer: timer2,

            eeprom_i2c: eeprom_i2c,
            net_interface: network_interface,
            eth_mac: eth_mac,
            mac_addr: mac_addr,
        }
    }

    #[task(binds = SPI3, resources = [adc2, dac2, iir_state, iir_ch], priority = 2)]
    fn spi3(c: spi3::Context) {
        c.resources.adc2.spi.ifcr.write(|w| w.eotc().set_bit());

        let output: u16 = {
            let a: u16 = c.resources.adc2.read().unwrap();
            let x0 = f32::from(a as i16);
            let y0 = c.resources.iir_ch[1].update(&mut c.resources.iir_state[1], x0);
            y0 as i16 as u16 ^ 0x8000
        };

        c.resources.dac2.spi.ifcr.write(|w| w.eotc().set_bit().txtfc().set_bit());
        c.resources.dac2.send(output).unwrap();
    }

    #[task(binds = SPI2, resources = [adc1, dac1, iir_state, iir_ch], priority = 2)]
    fn spi2(c: spi2::Context) {
        c.resources.adc1.spi.ifcr.write(|w| w.eotc().set_bit());

        let output: u16 = {
            let a: u16 = c.resources.adc1.read().unwrap();
            let x0 = f32::from(a as i16);
            let y0 = c.resources.iir_ch[0].update(&mut c.resources.iir_state[0], x0);
            y0 as i16 as u16 ^ 0x8000
        };

        c.resources.dac1.spi.ifcr.write(|w| w.eotc().set_bit().txtfc().set_bit());
        c.resources.dac1.send(output).unwrap();
    }

    #[idle(resources=[net_interface, mac_addr, eth_mac, iir_state, iir_ch, afe1, afe2])]
    fn idle(mut c: idle::Context) -> ! {

        let mut socket_set_entries: [_; 8] = Default::default();
        let mut sockets = net::socket::SocketSet::new(&mut socket_set_entries[..]);

        let mut rx_storage = [0; TCP_RX_BUFFER_SIZE];
        let mut tx_storage = [0; TCP_TX_BUFFER_SIZE];
        let tcp_handle = {
            let tcp_rx_buffer = net::socket::TcpSocketBuffer::new(&mut rx_storage[..]);
            let tcp_tx_buffer = net::socket::TcpSocketBuffer::new(&mut tx_storage[..]);
            let tcp_socket = net::socket::TcpSocket::new(tcp_rx_buffer, tcp_tx_buffer);
            sockets.add(tcp_socket)
        };

        let mut server = server::Server::new();

        let mut time = 0u32;
        let mut next_ms = Instant::now();

        // TODO: Replace with reference to CPU clock from CCDR.
        next_ms += 400_000.cycles();

        loop {
            let tick = Instant::now() > next_ms;

            if tick {
                next_ms += 400_000.cycles();
                time += 1;
            }

            {
                let socket =
                    &mut *sockets.get::<net::socket::TcpSocket>(tcp_handle);
                if socket.state() == net::socket::TcpState::CloseWait {
                    socket.close();
                } else if !(socket.is_open() || socket.is_listening()) {
                    socket
                        .listen(1235)
                        .unwrap_or_else(|e| warn!("TCP listen error: {:?}", e));
                } else {
                    server.poll(socket, |req| {
                        info!("Got request: {:?}", req);
                        route_request!(req,
                            readable_attributes: [
                                ("stabilizer/iir/state", (|| {
                                    let state = c.resources.iir_state.lock(|iir_state|
                                        server::Status {
                                            t: time,
                                            x0: iir_state[0][0],
                                            y0: iir_state[0][2],
                                            x1: iir_state[1][0],
                                            y1: iir_state[1][2],
                                    });

                                    Ok::<server::Status, ()>(state)
                                })),
                                ("stabilizer/afe1/gain", (|| c.resources.afe1.get_gain())),
                                ("stabilizer/afe2/gain", (|| c.resources.afe2.get_gain()))
                            ],

                            modifiable_attributes: [
                                ("stabilizer/iir1/state", server::IirRequest, (|req: server::IirRequest| {
                                    c.resources.iir_ch.lock(|iir_ch| {
                                        if req.channel > 1 {
                                            return Err(());
                                        }

                                        iir_ch[req.channel as usize] = req.iir;

                                        Ok::<server::IirRequest, ()>(req)
                                    })
                                })),
                                ("stabilizer/iir2/state", server::IirRequest, (|req: server::IirRequest| {
                                    c.resources.iir_ch.lock(|iir_ch| {
                                        if req.channel > 1 {
                                            return Err(());
                                        }

                                        iir_ch[req.channel as usize] = req.iir;

                                        Ok::<server::IirRequest, ()>(req)
                                    })
                                })),
                                ("stabilizer/afe1/gain", afe::Gain, (|gain| {
                                    Ok::<(), ()>(c.resources.afe1.set_gain(gain))
                                })),
                                ("stabilizer/afe2/gain", afe::Gain, (|gain| {
                                    Ok::<(), ()>(c.resources.afe2.set_gain(gain))
                                }))
                            ]
                        )
                    });
                }
            }

            let sleep = match c.resources.net_interface.poll(&mut sockets,
                                             net::time::Instant::from_millis(time as i64)) {
                Ok(changed) => changed == false,
                Err(net::Error::Unrecognized) => true,
                Err(e) => {
                    info!("iface poll error: {:?}", e);
                    true
                }
            };

            if sleep {
                cortex_m::asm::wfi();
            }
        }
    }

    #[task(binds = ETH, priority = 1)]
    fn eth(_: eth::Context) {
        unsafe { ethernet::interrupt_handler() }
    }

    extern "C" {
        // hw interrupt handlers for RTFM to use for scheduling tasks
        // one per priority
        fn DCMI();
        fn JPEG();
        fn SDMMC();
    }
};

#[exception]
fn HardFault(ef: &cortex_m_rt::ExceptionFrame) -> ! {
    panic!("HardFault at {:#?}", ef);
}

#[exception]
fn DefaultHandler(irqn: i16) {
    panic!("Unhandled exception (IRQn = {})", irqn);
}