use crate::device::sys_timer;
use core::cell::RefCell;
use cortex_m::interrupt::{CriticalSection, Mutex};
use log::{debug, info, warn};
use smoltcp::{
    iface::{
        self, Interface, SocketHandle, SocketSet, SocketStorage
    },
    socket::tcp::{State, SocketBuffer, Socket},
    wire::{EthernetAddress, IpAddress, IpCidr, Ipv4Address, Ipv4Cidr},
    time::Instant,
};
use stm32_eth::{
    Parts, EthPins, PartsIn, 
    dma::{
        TxRingEntry, RxRingEntry, EthernetDMA
    }};
use stm32f4xx_hal::{
    gpio::{gpioa::*, gpiob::*, gpioc::*, Alternate, Input}, 
    rcc::Clocks,
    interrupt,
};

const IPV4_ADDR: (u8, u8, u8, u8) = (192, 168, 1, 132);
const IP_INIT: IpCidr = IpCidr::Ipv4(Ipv4Cidr::new(
    Ipv4Address::new(IPV4_ADDR.0, IPV4_ADDR.1, IPV4_ADDR.2, IPV4_ADDR.3),
    24,
));
const ADDRESS: (IpAddress, u16) = (
    IpAddress::Ipv4(Ipv4Address::new(
        IPV4_ADDR.0,
        IPV4_ADDR.1,
        IPV4_ADDR.2,
        IPV4_ADDR.3,
    )),
    1337,
);

/// Interrupt pending flag: set by the `ETH` interrupt handler, should
/// be cleared before polling the interface.
static NET_PENDING: Mutex<RefCell<bool>> = Mutex::new(RefCell::new(false));
static mut INCOMING_BYTE: [u8; 512] = [0; 512];

pub struct ServerHandle {
    socket_handle: SocketHandle,
    socket_set: SocketSet<'static>,
    iface: EthInterface,
    dma: EthernetDMA<'static, 'static>,
}
pub type EthernetPins =
    EthPins<PA1<Input>, PA7<Input>, PB11<Input>, PB12<Input>, PB13<Input>, PC4<Input>, PC5<Input>>;
pub struct EthernetMgmtPins {
    pub mdio: PA2<Alternate<11>>,
    pub mdc: PC1<Alternate<11>>,
}
pub type EthInterface = Interface;

static mut RX_RING: Option<[RxRingEntry; 8]> = None;
static mut TX_RING: Option<[TxRingEntry; 2]> = None;
static mut SOCKET_STORAGE: Option<[SocketStorage<'static>; 1]> = None;

static mut TCP_SOCKET_STORAGE : Option<TcpSocketStorage> = None;

#[derive(Copy, Clone)]
pub struct TcpSocketStorage {
    rx_storage: [u8; 2048],
    tx_storage: [u8; 2048],
}

impl TcpSocketStorage {
    const fn new() -> Self {
        Self {
            rx_storage: [0; 2048],
            tx_storage: [0; 2048],
        }
    }
}

fn now_fn() -> smoltcp::time::Instant {
    Instant::from_millis(i64::from(sys_timer::now()))
}

static mut SERVER_HANDLE : Option<ServerHandle> = None;

impl ServerHandle {
    pub fn new (eth_pins: EthernetPins,
        eth_mgmt_pins: EthernetMgmtPins,
        ethernet_parts_in: PartsIn,
        clocks: Clocks,
        mac_addr: [u8; 6]
    ) {        
        let rx_ring = unsafe { RX_RING.get_or_insert(Default::default()) };
        let tx_ring = unsafe { TX_RING.get_or_insert(Default::default()) };
        let tcp_socket_storage = unsafe { TCP_SOCKET_STORAGE.get_or_insert(TcpSocketStorage::new()) };
        let socket_storage = unsafe { SOCKET_STORAGE.get_or_insert([SocketStorage::EMPTY; 1]) };

        let Parts {
            mut dma,
            mac,
            #[cfg(feature = "ptp")]
            ..
        } = stm32_eth::new_with_mii(
            ethernet_parts_in,
            &mut rx_ring[..],
            &mut tx_ring[..],
            clocks,
            eth_pins,
            eth_mgmt_pins.mdio,
            eth_mgmt_pins.mdc
        ).unwrap();

        let mut routes = smoltcp::iface::Routes::new();
        routes
            .add_default_ipv4_route(Ipv4Address::new(192, 168, 1, 1))
            .ok();
        dma.enable_interrupt();

        let rx_buffer = SocketBuffer::new(&mut tcp_socket_storage.rx_storage[..]);
        let tx_buffer = SocketBuffer::new(&mut tcp_socket_storage.tx_storage[..]);
        let socket = Socket::new(rx_buffer, tx_buffer);

        let config = iface::Config::new(EthernetAddress::from_bytes(&mac_addr).into());
        let mut iface = Interface::new(config, &mut &mut dma, smoltcp::time::Instant::ZERO);
        iface.set_hardware_addr(EthernetAddress(mac_addr).into());
        debug!("MAC ADDRESS: {:02X?}", EthernetAddress(mac_addr));

        iface.update_ip_addrs(|addr| {
            addr.push(IP_INIT).unwrap();
        });

        let mut sockets = SocketSet::new(&mut socket_storage[..]);
        let tcp_handle = sockets.add(socket);
        let socket = sockets.get_mut::<Socket>(tcp_handle);
        socket.listen(ADDRESS).ok();
        iface.poll(Instant::from_millis(i64::from(sys_timer::now())), &mut &mut dma, &mut sockets);
        
        let server = ServerHandle {
            socket_handle: tcp_handle,
            socket_set: sockets,
            iface: iface,
            dma: dma,
        };

        if let Ok(mut phy) = EthernetPhy::from_miim(mac, 0) {
            info!(
                "Resetting PHY as an extra step. Type: {}",
                phy.ident_string()
            );

            phy.phy_init();
        } else {
            info!("Not resetting unsupported PHY.");
        }

        unsafe {
            SERVER_HANDLE = Some(server);
        }
    }

    pub fn echo(&mut self, buffer: &mut [u8]) {
        self.iface.poll(now_fn(),  &mut &mut self.dma, &mut self.socket_set);
        let socket = self.socket_set.get_mut::<Socket>(self.socket_handle);

        if let Ok(recv_bytes) = socket.recv_slice(buffer) {
            if recv_bytes > 0 {
                socket.send_slice(&buffer[..recv_bytes]).ok();
                info!("Echoed {} bytes.", recv_bytes);
            }
        }

        if !socket.is_listening() && !socket.is_open() || socket.state() == State::CloseWait {
            socket.abort();
            socket.listen(ADDRESS).ok();
            warn!("Disconnected... Reopening listening socket.");
        }

        self.iface.poll(now_fn(), &mut &mut self.dma, &mut self.socket_set);
    }

    pub fn recv(&mut self, buffer: &mut [u8])-> Result<usize, smoltcp::socket::tcp::RecvError> {
        self.iface.poll(now_fn(),  &mut &mut self.dma, &mut self.socket_set);
        let socket = self.socket_set.get_mut::<Socket>(self.socket_handle);

        socket.recv_slice(buffer)
    }

    pub fn send(&mut self, buffer: &mut [u8], num_bytes: usize) {
        let socket = self.socket_set.get_mut::<Socket>(self.socket_handle);
        if num_bytes > 0 {
            socket.send_slice(&buffer[..num_bytes]).ok();
            info!("Sent {} bytes.", num_bytes);
        }
        
        // Send bytes out
        self.iface.poll(now_fn(), &mut &mut self.dma, &mut self.socket_set);
    }

    pub fn poll_socket_status(&mut self)-> bool {
        let socket = self.socket_set.get_mut::<Socket>(self.socket_handle);
        if !socket.is_listening() && !socket.is_open() || socket.state() == State::CloseWait {
            socket.abort();
            socket.listen(ADDRESS).ok();
            info!("Disconnected... Reopening listening socket.");
            return false;
        } else if socket.state() == State::Closed || socket.state() == State::Closing {
            return false;
        }
        return true;
    }
}

use ieee802_3_miim::{
    phy::{
        lan87xxa::{LAN8720A, LAN8742A},
        BarePhy, KSZ8081R,
    },
    Miim, Pause, Phy,
};

/// An ethernet PHY
pub enum EthernetPhy<M: Miim> {
    /// LAN8720A
    LAN8720A(LAN8720A<M>),
    /// LAN8742A
    LAN8742A(LAN8742A<M>),
    /// KSZ8081R
    KSZ8081R(KSZ8081R<M>),
}

impl<M: Miim> Phy<M> for EthernetPhy<M> {
    fn best_supported_advertisement(&self) -> ieee802_3_miim::AutoNegotiationAdvertisement {
        unimplemented!()
    }

    fn get_miim(&mut self) -> &mut M {
        match self {
            EthernetPhy::LAN8720A(phy) => phy.get_miim(),
            EthernetPhy::LAN8742A(phy) => phy.get_miim(),
            EthernetPhy::KSZ8081R(phy) => phy.get_miim(),
        }
    }

    fn get_phy_addr(&self) -> u8 {
        match self {
            EthernetPhy::LAN8720A(phy) => phy.get_phy_addr(),
            EthernetPhy::LAN8742A(phy) => phy.get_phy_addr(),
            EthernetPhy::KSZ8081R(phy) => phy.get_phy_addr(),
        }
    }
}

impl<M: Miim> EthernetPhy<M> {
    /// Attempt to create one of the known PHYs from the given
    /// MIIM.
    ///
    /// Returns an error if the PHY does not support the extended register
    /// set, or if the PHY's identifier does not correspond to a known PHY.
    pub fn from_miim(miim: M, phy_addr: u8) -> Result<Self, M> {
        let mut bare = BarePhy::new(miim, phy_addr, Pause::NoPause);
        let phy_ident = if let Some(id) = bare.phy_ident() {
            id.raw_u32()
        } else {
            return Err(bare.release());
        };
        let miim = bare.release();
        match phy_ident & 0xFFFFFFF0 {
            0x0007C0F0 => Ok(Self::LAN8720A(LAN8720A::new(miim, phy_addr))),
            0x0007C130 => Ok(Self::LAN8742A(LAN8742A::new(miim, phy_addr))),
            0x00221560 => Ok(Self::KSZ8081R(KSZ8081R::new(miim, phy_addr))),
            _ => Err(miim),
        }
    }

    /// Get a string describing the type of PHY
    pub const fn ident_string(&self) -> &'static str {
        match self {
            EthernetPhy::LAN8720A(_) => "LAN8720A",
            EthernetPhy::LAN8742A(_) => "LAN8742A",
            EthernetPhy::KSZ8081R(_) => "KSZ8081R",
        }
    }

    /// Initialize the PHY
    pub fn phy_init(&mut self) {
        match self {
            EthernetPhy::LAN8720A(phy) => phy.phy_init(),
            EthernetPhy::LAN8742A(phy) => phy.phy_init(),
            EthernetPhy::KSZ8081R(phy) => {
                phy.set_autonegotiation_advertisement(phy.best_supported_advertisement());
            }
        }
    }

    #[allow(dead_code)]
    pub fn speed(&mut self) -> Option<ieee802_3_miim::phy::PhySpeed> {
        match self {
            EthernetPhy::LAN8720A(phy) => phy.link_speed(),
            EthernetPhy::LAN8742A(phy) => phy.link_speed(),
            EthernetPhy::KSZ8081R(phy) => phy.link_speed(),
        }
    }

    #[allow(dead_code)]
    pub fn release(self) -> M {
        match self {
            EthernetPhy::LAN8720A(phy) => phy.release(),
            EthernetPhy::LAN8742A(phy) => phy.release(),
            EthernetPhy::KSZ8081R(phy) => phy.release(),
        }
    }
}

pub fn eth_send(buffer: &mut [u8], num_bytes: usize) {
    unsafe {
        if let Some(ref mut server_handle ) = SERVER_HANDLE {
            server_handle.send(buffer, num_bytes);
        }
        else {
            panic!("eth_send is called before init");
        }
    }
}

pub fn eth_recv(buffer: &mut [u8])-> usize{
    unsafe {
        if let Some(ref mut server_handle ) = SERVER_HANDLE {
            match server_handle.recv(buffer){
                Ok(recv_bytes) => {return recv_bytes}
                Err(err) => {
                    debug!("TCP Recv Error: {}", err);
                    return 0
                }
            };
        }
        else {
            panic!("eth_send is called before init");
        }
    }
}

pub fn eth_is_socket_active() -> bool {
    unsafe {
        if let Some(ref mut server_handle ) = SERVER_HANDLE {
            server_handle.poll_socket_status()
        }
        else {
            panic!("eth_is_socket_active is called before init");
        }
    }
}

/// Potentially wake up from `wfi()`, set the interrupt pending flag,
/// clear interrupt flags.
#[interrupt]
fn ETH() {
    let interrupt_reason = stm32_eth::eth_interrupt_handler();
    cortex_m::interrupt::free(|cs| {
        *NET_PENDING.borrow(cs)
            .borrow_mut() = true;
    });

    debug!("Ethernet Interrupt{:?}", interrupt_reason);
}

/// Has an interrupt occurred since last call to `clear_pending()`?
pub fn is_pending(cs: &CriticalSection) -> bool {
    *NET_PENDING.borrow(cs)
        .borrow()
}

/// Clear the interrupt pending flag before polling the interface for
/// data.
pub fn clear_pending(cs: &CriticalSection) {
    *NET_PENDING.borrow(cs)
        .borrow_mut() = false;
}