#![no_main]
#![no_std]
#![feature(core_intrinsics)]
#![feature(assoc_char_funcs)]
#![feature(alloc_error_handler)]

use log::{ trace, warn };
use stm32h7xx_hal::gpio::Speed;
use stm32h7xx_hal::rng::Rng;
use stm32h7xx_hal::{pac, prelude::*, spi};
use stm32h7xx_hal::ethernet;

use smoltcp as net;
use SaiTLS as tls;

use minimq::{ MqttClient, QoS };

use cortex_m;
use cortex_m_rt::entry;
use alloc_cortex_m::CortexMHeap;
use rtic::cyccnt::{Instant, U32Ext};
use rand_core::{RngCore, CryptoRng};

use tls::TlsRng;
use tls::tls::TlsSocket;
use tls::tcp_stack::NetworkStack;
use heapless::{ String, consts, consts::* };
use core::alloc::Layout;

#[macro_use]
pub mod bitmask_macro;
pub mod spi_slave;
pub mod cpld;
use crate::cpld::CPLD;
pub mod config_register;
pub mod attenuator;
pub mod dds;
pub mod net_store;
use crate::net_store::NetStorage;
pub mod fpga;
use crate::fpga::flash_ice40_fpga;
pub mod mqtt_mux;
use crate::mqtt_mux::MqttMux;
pub mod urukul;
use crate::urukul::Urukul;
pub mod flash;
pub mod config;
use crate::config::get_net_config;
pub mod flash_store;
use crate::flash_store::init_flash;

mod logger;

#[global_allocator]
static ALLOCATOR: CortexMHeap = CortexMHeap::empty();

#[alloc_error_handler]
fn oom(_: Layout) -> ! {
    warn!("Out of memory!");
    loop {}
}

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],
    routes_cache: [None; 8],
};

#[link_section = ".sram3.eth"]
static mut DES_RING: ethernet::DesRing = ethernet::DesRing::new();
#[link_section = ".sram3.tx_store"]
static mut TX_STORAGE: [u8; 8192] = [0; 8192];
#[link_section = ".sram3.rx_store"]
static mut RX_STORAGE: [u8; 8192] = [0; 8192];

struct RngStruct {
    rng: Rng
}

impl RngCore for RngStruct {
    fn next_u32(&mut self) -> u32 {
        self.rng.gen().unwrap()
    }

    fn next_u64(&mut self) -> u64 {
        (u64::from(self.next_u32()) << 32) | u64::from(self.next_u32())
    }

    fn fill_bytes(&mut self, dest: &mut [u8]) {
        self.rng.fill(dest).unwrap();
    }

    fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), rand_core::Error> {
        Ok(self.fill_bytes(dest))
    }
}

impl CryptoRng for RngStruct {}

impl TlsRng for RngStruct {}

#[entry]
fn main() -> ! {

    // Initialize the allocator BEFORE you use it
    let start = cortex_m_rt::heap_start() as usize;
    let size = 32768; // in bytes
    unsafe { ALLOCATOR.init(start, size) }

    let mut cp = cortex_m::Peripherals::take().unwrap();
    let dp = pac::Peripherals::take().unwrap();

    unsafe {
        logger::enable_itm(&dp.DBGMCU, &mut cp.DCB, &mut cp.ITM);
    }
    logger::init();

    // Enable SRAM3 for the descriptor ring and smoltcp buffers.
    dp.RCC.ahb2enr.modify(|_, w| w.sram3en().set_bit());
    // Enable SRAM2 for the RAM management buffer
    dp.RCC.ahb2enr.modify(|_, w| w.sram2en().set_bit());

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

    let rcc = dp.RCC.constrain();
    let ccdr = rcc
        .use_hse(8.mhz())
        .sys_ck(400.mhz())
        .hclk(200.mhz())
        .pll1_q_ck(48.mhz())
        .pll1_r_ck(400.mhz())
        .freeze(vos, &dp.SYSCFG);
    
    let delay = cp.SYST.delay(ccdr.clocks);
    
    cp.SCB.invalidate_icache();
    cp.SCB.enable_icache();

    cp.DWT.enable_cycle_counter();

    // Instantiate random number generator
    let mut rng = RngStruct {
        rng: dp.RNG.constrain(ccdr.peripheral.RNG, &ccdr.clocks)
    };

    // Create sfkv store and flash storage manager
    let (flash, mut flash_store) = init_flash(dp.FLASH);

    // Acquire client/broker IP Address, client MAC address from flash memory
    let net_config = get_net_config(&mut flash_store);

    let gpioa = dp.GPIOA.split(ccdr.peripheral.GPIOA);
    let gpiob = dp.GPIOB.split(ccdr.peripheral.GPIOB);
    let gpioc = dp.GPIOC.split(ccdr.peripheral.GPIOC);
    let gpiod = dp.GPIOD.split(ccdr.peripheral.GPIOD);
    let _gpioe = dp.GPIOE.split(ccdr.peripheral.GPIOE);
    let gpiof = dp.GPIOF.split(ccdr.peripheral.GPIOF);
    let gpiog = dp.GPIOG.split(ccdr.peripheral.GPIOG);

    // Note: ITM doesn't work beyond this, due to a pin conflict between:
    // - FPGA_SPI: SCK  (af5)
    // - ST_LINK SWO    (af0)
    // Both demands PB3
    trace!("Flashing configuration bitstream to iCE40 HX8K on Humpback.");

    // Using SPI_1 alternate functions (af5)
    let fpga_sck = gpiob.pb3.into_alternate_af5();
    let fpga_sdo = gpiob.pb4.into_alternate_af5();
    let fpga_sdi = gpiob.pb5.into_alternate_af5();

    // Setup SPI_SS_B and CRESET_B
    let fpga_ss = gpioa.pa4.into_push_pull_output();
    let fpga_creset = gpiof.pf3.into_open_drain_output();

    // Setup CDONE
    let fpga_cdone = gpiod.pd15.into_pull_up_input();

    // Setup SPI interface
    let fpga_cfg_spi = dp.SPI1.spi(
        (fpga_sck, fpga_sdo, fpga_sdi),
        spi::MODE_3,
        12.mhz(),
        ccdr.peripheral.SPI1,
        &ccdr.clocks,
    );

    flash_ice40_fpga(fpga_cfg_spi, fpga_ss, fpga_creset, fpga_cdone, delay).unwrap();

    // Configure ethernet IO
    {
        let _rmii_refclk = gpioa.pa1.into_alternate_af11().set_speed(Speed::VeryHigh);
        let _rmii_mdio = gpioa.pa2.into_alternate_af11().set_speed(Speed::VeryHigh);
        let _rmii_mdc = gpioc.pc1.into_alternate_af11().set_speed(Speed::VeryHigh);
        let _rmii_crs_dv = gpioa.pa7.into_alternate_af11().set_speed(Speed::VeryHigh);
        let _rmii_rxd0 = gpioc.pc4.into_alternate_af11().set_speed(Speed::VeryHigh);
        let _rmii_rxd1 = gpioc.pc5.into_alternate_af11().set_speed(Speed::VeryHigh);
        let _rmii_tx_en = gpiog.pg11.into_alternate_af11().set_speed(Speed::VeryHigh);
        let _rmii_txd0 = gpiog.pg13.into_alternate_af11().set_speed(Speed::VeryHigh);
        let _rmii_txd1 = gpiob.pb13.into_alternate_af11().set_speed(Speed::VeryHigh);
    }

    // Configure ethernet
    // let mac_addr = net::wire::EthernetAddress([0xAC, 0x6F, 0x7A, 0xDE, 0xD6, 0xC8]);
    let (eth_dma, mut eth_mac) = unsafe {
        ethernet::new_unchecked(
            dp.ETHERNET_MAC,
            dp.ETHERNET_MTL,
            dp.ETHERNET_DMA,
            &mut DES_RING,
            net_config.eth_addr.clone(),
        )
    };

    unsafe { ethernet::enable_interrupt() }

    let store = unsafe { &mut NET_STORE };

    store.ip_addrs[0] = net_config.ip_cidr;

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

    let mut routes = net::iface::Routes::new(&mut store.routes_cache[..]);
    let default_v4_gw = net::wire::Ipv4Address::new(192, 168, 1, 1);
    routes.add_default_ipv4_route(default_v4_gw).unwrap();

    let mut net_interface = net::iface::EthernetInterfaceBuilder::new(eth_dma)
        .ethernet_addr(net_config.eth_addr)
        .neighbor_cache(neighbor_cache)
        .ip_addrs(&mut store.ip_addrs[..])
        .routes(routes)
        .finalize();

    /*
     *    Using SPI6
     *    SCLK -> PA5        (af8)
     *    MOSI -> PG14       (af5)
     *    MISO -> PA6        (af8)
     *    CS -> 0: PB12, 1: PA15, 2: PC7
     */
    let sclk = gpioa.pa5.into_alternate_af8().set_speed(Speed::VeryHigh);
    let mosi = gpiog.pg14.into_alternate_af5().set_speed(Speed::VeryHigh);
    let miso = gpioa.pa6.into_alternate_af8().set_speed(Speed::VeryHigh);
    let (cs0, cs1, cs2) = (
        gpiob.pb12.into_push_pull_output(),
        gpioa.pa15.into_push_pull_output(),
        gpioc.pc7.into_push_pull_output(),
    );

    /*
     *  I/O_Update -> PB15
     */
    let io_update = gpiob.pb15.into_push_pull_output();

    let spi = dp.SPI6.spi(
        (sclk, miso, mosi),
        spi::MODE_0,
        2.mhz(),
        ccdr.peripheral.SPI6,
        &ccdr.clocks,
    );

    let switch = CPLD::new(spi, (cs0, cs1, cs2), io_update);
    let parts = switch.split();

    let urukul = Urukul::new(
        parts.spi1, parts.spi2, parts.spi3, parts.spi4, parts.spi5, parts.spi6, parts.spi7
    );

    let mut mqtt_mux = MqttMux::new(urukul, flash, flash_store, net_config.name.as_str());

    // Time unit in ms
    let mut time: u32 = 0;

    // Cycle counter for 1 ms
    // This effectively provides a conversion from rtic unit to ms
    let mut next_ms = Instant::now();
    next_ms += 400_000.cycles();

    let mut tls_socket_entries: [_; 1] = Default::default();
    let mut tls_socket_set = tls::set::TlsSocketSet::new(
        &mut tls_socket_entries[..]
    );

    let tx_buffer = net::socket::TcpSocketBuffer::new(unsafe { &mut TX_STORAGE[..] });
    let rx_buffer = net::socket::TcpSocketBuffer::new(unsafe { &mut RX_STORAGE[..] });
    let mut tcp_socket = net::socket::TcpSocket::new(rx_buffer, tx_buffer);
    tcp_socket.set_keep_alive(
        Some(net::time::Duration::from_secs(2))
    );

    let tls_socket = TlsSocket::new(
        tcp_socket,
        &mut rng,
        None
    );
    let _ = tls_socket_set.add(tls_socket);

    let tls_stack = NetworkStack::new(
        tls_socket_set
    );

    let mut client = MqttClient::<consts::U2048, _>::new(
        net_config.broker_ip,
        net_config.name.as_str(),
        tls_stack,
    )
    .unwrap();

    let mut tick = false;
    let mut has_subscribed = false;

    loop {
        // Update time accumulator in ms
        // Tick once every ms
        if Instant::now() > next_ms {
            tick = true;
            time += 1;
            next_ms += 400_000.cycles();
        }

        // eth Poll if necessary
        // Do not poll if eth link is down
        while !eth_mac.phy_poll_link() {}
        client.network_stack.poll(&mut net_interface, net::time::Instant::from_millis(time));

        // Process MQTT messages about Urukul/Control
        let connection = match client
            .poll(|_client, topic, message, _properties| {
                mqtt_mux.process_mqtt_ingress(topic, message);
            }) {
                Ok(_) => true,
                Err(e) => {
                    log::info!("Warn: {:?}", e);
                    false
                },
            };
        
        // Process MQTT response messages about Urukul
        for (topic, message) in mqtt_mux.process_mqtt_egress().unwrap() {
            client.publish(
                topic.as_str(),
                message.as_bytes(),
                QoS::AtMostOnce,
                &[]
            ).unwrap();
        }
        
        if connection && !has_subscribed && tick {
            let mut str_builder: String<U128> = String::from(net_config.name.as_str());
            str_builder.push_str("/Control/#").unwrap();
            match client.subscribe(str_builder.as_str(), &[]) {
                Ok(()) => has_subscribed = true,
                Err(minimq::Error::NotReady) => {},
                _e => {},
            };
        }

        // Reset tick flag
        tick = false;
    }
}