#![no_main]
#![no_std]

//extern crate cortex_m_rt as rt;
use core::sync::atomic::{AtomicU32, Ordering};

//#[macro_use]
//extern crate log;

//extern crate cortex_m
use panic_semihosting as _;

use cortex_m;
use cortex_m::asm::nop;
use cortex_m_rt::{
    entry,
    exception,
};
use cortex_m_semihosting::hprintln;

extern crate smoltcp;
extern crate stm32h7_ethernet as ethernet;

use stm32h7xx_hal::gpio::Speed;
use stm32h7xx_hal::hal::digital::v2::OutputPin;
use stm32h7xx_hal::rcc::CoreClocks;
use stm32h7xx_hal::{pac, prelude::*, stm32, stm32::interrupt};
use Speed::*;

/*
#[cfg(feature = "itm")]
use cortex_m_log::log::{trick_init, Logger};

#[cfg(feature = "itm")]
use cortex_m_log::{
    destination::Itm, printer::itm::InterruptSync as InterruptSyncItm,
};
*/

use core::{
    str,
    fmt::Write
};
use core::mem::uninitialized;

// Exception: no phy::wait
//use smoltcp::phy::wait as phy_wait;
use smoltcp::wire::{EthernetAddress, IpAddress, IpCidr};
use smoltcp::iface::{NeighborCache, EthernetInterfaceBuilder};
use smoltcp::socket::SocketSet;
//use smoltcp::socket::{UdpSocket, UdpSocketBuffer, UdpPacketMetadata};
use smoltcp::socket::{SocketHandle, TcpSocket, TcpSocketBuffer};
use smoltcp::time::{Duration, Instant};


/// Configure SYSTICK for 1ms timebase
fn systick_init(syst: &mut stm32::SYST, clocks: CoreClocks) {
    let c_ck_mhz = clocks.c_ck().0 / 1_000_000;

    let syst_calib = 0x3E8;

    syst.set_clock_source(cortex_m::peripheral::syst::SystClkSource::Core);
    syst.set_reload((syst_calib * c_ck_mhz) - 1);
    syst.enable_interrupt();
    syst.enable_counter();
}

/// ======================================================================
/// Entry point
/// ======================================================================

/// TIME is an atomic u32 that counts milliseconds. Although not used
/// here, it is very useful to have for network protocols
static TIME: AtomicU32 = AtomicU32::new(0);

/// Locally administered MAC address
const MAC_ADDRESS: [u8; 6] = [0x02, 0x00, 0x11, 0x22, 0x33, 0x44];

/// Ethernet descriptor rings are a global singleton
#[link_section = ".sram3.eth"]
static mut DES_RING: ethernet::DesRing = ethernet::DesRing::new();

// Theoratical maximum number of socket that can be handled
const SOCKET_COUNT: usize = 2;

// Give buffer sizes of transmitting and receiving TCP packets
const TCP_RX_BUFFER_SIZE: usize = 2048;
const TCP_TX_BUFFER_SIZE: usize = 2048;

// the program entry point
#[entry]
fn main() -> ! {

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

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

    // Initialise SRAM3
    dp.RCC.ahb2enr.modify(|_, w| w.sram3en().set_bit());

    // Initialise clocks...
    let rcc = dp.RCC.constrain();
    let ccdr = rcc
        .sys_ck(200.mhz())
        .hclk(200.mhz())
        .pll1_r_ck(100.mhz()) // for TRACECK
        .freeze(vos, &dp.SYSCFG);

    // Get the delay provider.
    let delay = cp.SYST.delay(ccdr.clocks);

    // Initialise system...
    cp.SCB.invalidate_icache();
    cp.SCB.enable_icache();
    // TODO: ETH DMA coherence issues
    // cp.SCB.enable_dcache(&mut cp.CPUID);
    cp.DWT.enable_cycle_counter();

    // Initialise IO...
    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 gpioe = dp.GPIOE.split(ccdr.peripheral.GPIOE);
    let gpiog = dp.GPIOG.split(ccdr.peripheral.GPIOG);
    let mut link_led = gpiob.pb0.into_push_pull_output(); // LED1, green
    let mut status_led = gpioe.pe1.into_push_pull_output(); // LD2, yellow
    let mut listen_led = gpiob.pb14.into_push_pull_output(); // LD3, red
    link_led.set_low().ok();
    status_led.set_low().ok();
    listen_led.set_low().ok();

    let _rmii_ref_clk = gpioa.pa1.into_alternate_af11().set_speed(VeryHigh);
    let _rmii_mdio = gpioa.pa2.into_alternate_af11().set_speed(VeryHigh);
    let _rmii_mdc = gpioc.pc1.into_alternate_af11().set_speed(VeryHigh);
    let _rmii_crs_dv = gpioa.pa7.into_alternate_af11().set_speed(VeryHigh);
    let _rmii_rxd0 = gpioc.pc4.into_alternate_af11().set_speed(VeryHigh);
    let _rmii_rxd1 = gpioc.pc5.into_alternate_af11().set_speed(VeryHigh);
    let _rmii_tx_en = gpiog.pg11.into_alternate_af11().set_speed(VeryHigh);
    let _rmii_txd0 = gpiog.pg13.into_alternate_af11().set_speed(VeryHigh);
    let _rmii_txd1 = gpiob.pb13.into_alternate_af11().set_speed(VeryHigh);

    // Initialise ethernet...
    assert_eq!(ccdr.clocks.hclk().0, 200_000_000); // HCLK 200MHz
    assert_eq!(ccdr.clocks.pclk1().0, 100_000_000); // PCLK 100MHz
    assert_eq!(ccdr.clocks.pclk2().0, 100_000_000); // PCLK 100MHz
    assert_eq!(ccdr.clocks.pclk4().0, 100_000_000); // PCLK 100MHz

    let mac_addr = smoltcp::wire::EthernetAddress::from_bytes(&MAC_ADDRESS);
    let (_eth_dma, mut 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();
        cp.NVIC.set_priority(stm32::Interrupt::ETH, 196); // Mid prio
        cortex_m::peripheral::NVIC::unmask(stm32::Interrupt::ETH);
    }

    // ----------------------------------------------------------
    // Begin periodic tasks

    systick_init(&mut delay.free(), ccdr.clocks);
    unsafe {
        cp.SCB.shpr[15 - 4].write(128);
    } // systick exception priority

    // ----------------------------------------------------------
    // Main application loop

    // Setup addresses, maybe not MAC?
    // MAC is set up in prior
    let local_addr = IpAddress::v4(192, 168, 1, 200);
    let mut ip_addrs = [IpCidr::new(local_addr, 24)];

    // let neighbor_cache = NeighborCache::new(BTreeMap::new());
    let mut neighbor_storage = [None; 16];
    let neighbor_cache = NeighborCache::new(&mut neighbor_storage[..]);

    // Device? _eth_dma, as it implements phy::device
    let mut iface = EthernetInterfaceBuilder::new(_eth_dma)
            .ethernet_addr(mac_addr)
            .neighbor_cache(neighbor_cache)
            .ip_addrs(&mut ip_addrs[..])
            .finalize();

    // TODO: Need Iinitialize TCP socket storage?
    // Yes cannot into vectors
    let mut rx_storage = [0; TCP_RX_BUFFER_SIZE];
    let mut tx_storage = [0; TCP_TX_BUFFER_SIZE];

    // Setup TCP sockets
    let tcp1_rx_buffer = TcpSocketBuffer::new(&mut rx_storage[..]);
    let tcp1_tx_buffer = TcpSocketBuffer::new(&mut tx_storage[..]);
    let mut tcp1_socket = TcpSocket::new(tcp1_rx_buffer, tcp1_tx_buffer);

    // Setup a silent socket
    let mut silent_rx_storage = [0; TCP_RX_BUFFER_SIZE];
    let mut silent_tx_storage = [0; TCP_TX_BUFFER_SIZE];
    let silent_rx_buffer = TcpSocketBuffer::new(&mut silent_rx_storage[..]);
    let silent_tx_buffer = TcpSocketBuffer::new(&mut silent_tx_storage[..]);
    let mut silent_socket = TcpSocket::new(silent_rx_buffer, silent_tx_buffer);

    // Socket storage
    let mut sockets_storage = [ None, None ];

    let mut sockets = SocketSet::new(&mut sockets_storage[..]);
    let tcp1_handle = sockets.add(tcp1_socket);
    let silent_handle = sockets.add(silent_socket);
    let mut handles: [SocketHandle; SOCKET_COUNT] = unsafe {
        uninitialized()
    };

    let mut eth_up = false;
    let mut receive_and_not_send = true;
    let mut counter = 0;

    // Record activeness of silent socket, init as false
    let mut silent_socket_active = false;

    loop {
        let _time = TIME.load(Ordering::Relaxed);
        let eth_last = eth_up;
        match iface.poll(&mut sockets, Instant::from_millis(_time as i64)) {
            Ok(_) => {
                eth_up = true;
                link_led.set_high().unwrap();
            },
            Err(e) => {
                eth_up = false;
                link_led.set_low().unwrap();
            },
        };

	// Counting socket (:6969)
        {
            let mut socket = sockets.get::<TcpSocket>(tcp1_handle);
            if !socket.is_open() {
                socket.listen(6969).unwrap();
                socket.set_timeout(Some(Duration::from_millis(5000)));
            }

            match socket.is_listening() {
                false => listen_led.set_low().unwrap(),
                _ => listen_led.set_high().unwrap(),
            };

            match socket.is_active() {
                true => status_led.set_high().unwrap(),
                _ => status_led.set_low().unwrap(),
            };

            if socket.can_recv() && receive_and_not_send {
				hprintln!("recv 6969");
                let data = socket.recv(|buffer| {
                    counter += buffer.len();
                    (buffer.len(), buffer)
                });
				hprintln!("{:?}", data);
       	        receive_and_not_send = false;
            }
		    else if socket.can_recv() {
				hprintln!("{:?}", socket.can_recv());
		    }

            if socket.can_send() && !receive_and_not_send {
                writeln!(socket, "{}", counter);
                receive_and_not_send = true;
            }
        }
		// Silent socket (:7000)
		{
		    let mut socket = sockets.get::<TcpSocket>(silent_handle);
		    if !socket.is_open() {
				socket.listen(7000).unwrap();
				socket.set_timeout(Some(Duration::from_millis(1000000)));
		    }

		    if socket.is_active() && !silent_socket_active {
				hprintln!("tcp:7000 connected").unwrap();
		    }
		    else if !socket.is_active() && silent_socket_active {
				hprintln!("tcp:7000 disconnected").unwrap();
				socket.close();
		    }
		    // Update socket activeness
		    silent_socket_active = socket.is_active();
		

		    if socket.can_recv() {
		//		hprintln!("About to recv").unwrap();
				hprintln!("{:?}", socket.recv(|buffer| {
				    (buffer.len(), str::from_utf8(buffer).unwrap())
				})).unwrap();
		    }
		}
    }
}

#[interrupt]
fn ETH() {
    unsafe { ethernet::interrupt_handler() }
}

#[exception]
fn SysTick() {
    TIME.fetch_add(1, Ordering::Relaxed);
}

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

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