#![macro_use]

use crate::dma::NoDma;
use crate::gpio::{AnyPin, Pin};
use crate::pac::gpio::vals::{Afr, Moder};
use crate::pac::gpio::Gpio;
use crate::pac::spi;
use crate::spi::{
    ByteOrder, Config, Error, Instance, MisoPin, MosiPin, RxDmaChannel, SckPin, TxDmaChannel,
    WordSize,
};
use crate::time::Hertz;
use core::future::Future;
use core::marker::PhantomData;
use core::ptr;
use embassy::util::Unborrow;
use embassy_extras::unborrow;
use embassy_traits::spi as traits;
pub use embedded_hal::spi::{Mode, Phase, Polarity, MODE_0, MODE_1, MODE_2, MODE_3};

use futures::future::join;

impl WordSize {
    fn dsize(&self) -> u8 {
        match self {
            WordSize::EightBit => 0b0111,
            WordSize::SixteenBit => 0b1111,
        }
    }

    fn _frxth(&self) -> spi::vals::Fthlv {
        match self {
            WordSize::EightBit => spi::vals::Fthlv::ONEFRAME,
            WordSize::SixteenBit => spi::vals::Fthlv::ONEFRAME,
        }
    }
}

#[allow(unused)]
pub struct Spi<'d, T: Instance, Tx = NoDma, Rx = NoDma> {
    sck: AnyPin,
    mosi: AnyPin,
    miso: AnyPin,
    txdma: Tx,
    rxdma: Rx,
    phantom: PhantomData<&'d mut T>,
}

impl<'d, T: Instance, Tx, Rx> Spi<'d, T, Tx, Rx> {
    pub fn new<F>(
        _peri: impl Unborrow<Target = T> + 'd,
        sck: impl Unborrow<Target = impl SckPin<T>>,
        mosi: impl Unborrow<Target = impl MosiPin<T>>,
        miso: impl Unborrow<Target = impl MisoPin<T>>,
        txdma: impl Unborrow<Target = Tx>,
        rxdma: impl Unborrow<Target = Rx>,
        freq: F,
        config: Config,
    ) -> Self
    where
        F: Into<Hertz>,
    {
        unborrow!(sck, mosi, miso, txdma, rxdma);

        unsafe {
            Self::configure_pin(sck.block(), sck.pin() as _, sck.af_num());
            //sck.block().otyper().modify(|w| w.set_ot(sck.pin() as _, crate::pac::gpio::vals::Ot::PUSHPULL));
            Self::configure_pin(mosi.block(), mosi.pin() as _, mosi.af_num());
            //mosi.block().otyper().modify(|w| w.set_ot(mosi.pin() as _, crate::pac::gpio::vals::Ot::PUSHPULL));
            Self::configure_pin(miso.block(), miso.pin() as _, miso.af_num());
        }

        let sck = sck.degrade();
        let mosi = mosi.degrade();
        let miso = miso.degrade();

        let pclk = T::frequency();
        let br = Self::compute_baud_rate(pclk, freq.into());
        unsafe {
            T::enable();
            T::reset();
            T::regs().ifcr().write(|w| w.0 = 0xffff_ffff);
            T::regs().cfg2().modify(|w| {
                //w.set_ssoe(true);
                w.set_ssoe(false);
                w.set_cpha(
                    match config.mode.phase == Phase::CaptureOnSecondTransition {
                        true => spi::vals::Cpha::SECONDEDGE,
                        false => spi::vals::Cpha::FIRSTEDGE,
                    },
                );
                w.set_cpol(match config.mode.polarity == Polarity::IdleHigh {
                    true => spi::vals::Cpol::IDLEHIGH,
                    false => spi::vals::Cpol::IDLELOW,
                });
                w.set_lsbfrst(match config.byte_order {
                    ByteOrder::LsbFirst => spi::vals::Lsbfrst::LSBFIRST,
                    ByteOrder::MsbFirst => spi::vals::Lsbfrst::MSBFIRST,
                });
                w.set_ssm(true);
                w.set_master(spi::vals::Master::MASTER);
                w.set_comm(spi::vals::Comm::FULLDUPLEX);
                w.set_ssom(spi::vals::Ssom::ASSERTED);
                w.set_midi(0);
                w.set_mssi(0);
                w.set_afcntr(spi::vals::Afcntr::CONTROLLED);
                w.set_ssiop(spi::vals::Ssiop::ACTIVEHIGH);
            });
            T::regs().cfg1().modify(|w| {
                w.set_crcen(false);
                w.set_mbr(spi::vals::Mbr(br));
                w.set_dsize(WordSize::EightBit.dsize());
                //w.set_fthlv(WordSize::EightBit.frxth());
            });
            T::regs().cr2().modify(|w| {
                w.set_tsize(0);
                w.set_tser(0);
            });
            T::regs().cr1().modify(|w| {
                w.set_ssi(false);
                w.set_spe(true);
            });
        }

        Self {
            sck,
            mosi,
            miso,
            txdma,
            rxdma,
            phantom: PhantomData,
        }
    }

    unsafe fn configure_pin(block: Gpio, pin: usize, af_num: u8) {
        let (afr, n_af) = if pin < 8 { (0, pin) } else { (1, pin - 8) };
        block.moder().modify(|w| w.set_moder(pin, Moder::ALTERNATE));
        block.afr(afr).modify(|w| w.set_afr(n_af, Afr(af_num)));
        block
            .ospeedr()
            .modify(|w| w.set_ospeedr(pin, crate::pac::gpio::vals::Ospeedr::VERYHIGHSPEED));
    }

    unsafe fn unconfigure_pin(block: Gpio, pin: usize) {
        block.moder().modify(|w| w.set_moder(pin, Moder::ANALOG));
    }

    fn compute_baud_rate(clocks: Hertz, freq: Hertz) -> u8 {
        match clocks.0 / freq.0 {
            0 => unreachable!(),
            1..=2 => 0b000,
            3..=5 => 0b001,
            6..=11 => 0b010,
            12..=23 => 0b011,
            24..=39 => 0b100,
            40..=95 => 0b101,
            96..=191 => 0b110,
            _ => 0b111,
        }
    }

    fn set_word_size(word_size: WordSize) {
        unsafe {
            T::regs().cr1().modify(|w| {
                w.set_csusp(true);
            });
            while T::regs().sr().read().eot() {}
            T::regs().cr1().modify(|w| {
                w.set_spe(false);
            });
            T::regs().cfg1().modify(|w| {
                w.set_dsize(word_size.dsize());
            });
            T::regs().cr1().modify(|w| {
                w.set_spe(true);
            });
        }
    }

    #[allow(unused)]
    async fn write_dma_u8(&mut self, write: &[u8]) -> Result<(), Error>
    where
        Tx: TxDmaChannel<T>,
    {
        let request = self.txdma.request();
        let dst = T::regs().txdr().ptr() as *mut u8;
        let f = self.txdma.write(request, write, dst);
        unsafe {
            T::regs().cfg1().modify(|reg| {
                reg.set_txdmaen(true);
            });
        }

        f.await;
        Ok(())
    }

    #[allow(unused)]
    async fn read_dma_u8(&mut self, read: &mut [u8]) -> Result<(), Error>
    where
        Tx: TxDmaChannel<T>,
        Rx: RxDmaChannel<T>,
    {
        let clock_byte_count = read.len();

        let rx_request = self.rxdma.request();
        let rx_src = T::regs().rxdr().ptr() as *mut u8;
        let rx_f = self.rxdma.read(rx_request, rx_src, read);

        let tx_request = self.txdma.request();
        let tx_dst = T::regs().txdr().ptr() as *mut u8;
        let clock_byte = 0x00;
        let tx_f = self
            .txdma
            .write_x(tx_request, &clock_byte, clock_byte_count, tx_dst);

        unsafe {
            T::regs().cfg1().modify(|reg| {
                reg.set_txdmaen(true);
                reg.set_rxdmaen(true);
            });
        }

        let r = join(tx_f, rx_f).await;
        Ok(())
    }

    #[allow(unused)]
    async fn read_write_dma_u8(&mut self, read: &mut [u8], write: &[u8]) -> Result<(), Error>
    where
        Tx: TxDmaChannel<T>,
        Rx: RxDmaChannel<T>,
    {
        let clock_byte_count = read.len();

        let rx_request = self.rxdma.request();
        let rx_src = T::regs().rxdr().ptr() as *mut u8;
        let rx_f = self.rxdma.read(rx_request, rx_src, read);

        let tx_request = self.txdma.request();
        let tx_dst = T::regs().txdr().ptr() as *mut u8;
        let tx_f = self.txdma.write(tx_request, write, tx_dst);

        unsafe {
            T::regs().cfg1().modify(|reg| {
                reg.set_txdmaen(true);
                reg.set_rxdmaen(true);
            });
        }

        let r = join(tx_f, rx_f).await;
        Ok(())
    }
}

impl<'d, T: Instance, Tx, Rx> Drop for Spi<'d, T, Tx, Rx> {
    fn drop(&mut self) {
        unsafe {
            Self::unconfigure_pin(self.sck.block(), self.sck.pin() as _);
            Self::unconfigure_pin(self.mosi.block(), self.mosi.pin() as _);
            Self::unconfigure_pin(self.miso.block(), self.miso.pin() as _);
        }
    }
}

impl<'d, T: Instance> embedded_hal::blocking::spi::Write<u8> for Spi<'d, T, NoDma> {
    type Error = Error;

    fn write(&mut self, words: &[u8]) -> Result<(), Self::Error> {
        Self::set_word_size(WordSize::EightBit);
        let regs = T::regs();

        for word in words.iter() {
            while unsafe { !regs.sr().read().txp() } {
                // spin
            }
            unsafe {
                let txdr = regs.txdr().ptr() as *mut u8;
                ptr::write_volatile(txdr, *word);
                regs.cr1().modify(|reg| reg.set_cstart(true));
            }
            loop {
                let sr = unsafe { regs.sr().read() };
                if sr.tifre() {
                    return Err(Error::Framing);
                }
                if sr.ovr() {
                    return Err(Error::Overrun);
                }
                if sr.crce() {
                    return Err(Error::Crc);
                }
                if !sr.txp() {
                    // loop waiting for TXE
                }
            }
        }

        Ok(())
    }
}

impl<'d, T: Instance> embedded_hal::blocking::spi::Transfer<u8> for Spi<'d, T, NoDma> {
    type Error = Error;

    fn transfer<'w>(&mut self, words: &'w mut [u8]) -> Result<&'w [u8], Self::Error> {
        Self::set_word_size(WordSize::EightBit);
        let regs = T::regs();

        for word in words.iter_mut() {
            unsafe {
                regs.cr1().modify(|reg| {
                    reg.set_ssi(false);
                });
            }
            while unsafe { !regs.sr().read().txp() } {
                // spin
            }
            unsafe {
                let txdr = regs.txdr().ptr() as *mut u8;
                ptr::write_volatile(txdr, *word);
                regs.cr1().modify(|reg| reg.set_cstart(true));
            }
            loop {
                let sr = unsafe { regs.sr().read() };

                if sr.rxp() {
                    break;
                }
                if sr.tifre() {
                    return Err(Error::Framing);
                }
                if sr.ovr() {
                    return Err(Error::Overrun);
                }
                if sr.crce() {
                    return Err(Error::Crc);
                }
            }
            unsafe {
                let rxdr = regs.rxdr().ptr() as *const u8;
                *word = ptr::read_volatile(rxdr);
            }
            let sr = unsafe { regs.sr().read() };
            if sr.tifre() {
                return Err(Error::Framing);
            }
            if sr.ovr() {
                return Err(Error::Overrun);
            }
            if sr.crce() {
                return Err(Error::Crc);
            }
        }

        Ok(words)
    }
}

impl<'d, T: Instance> embedded_hal::blocking::spi::Write<u16> for Spi<'d, T, NoDma> {
    type Error = Error;

    fn write(&mut self, words: &[u16]) -> Result<(), Self::Error> {
        Self::set_word_size(WordSize::SixteenBit);
        let regs = T::regs();

        for word in words.iter() {
            while unsafe { !regs.sr().read().txp() } {
                // spin
            }
            unsafe {
                let txdr = regs.txdr().ptr() as *mut u16;
                ptr::write_volatile(txdr, *word);
                regs.cr1().modify(|reg| reg.set_cstart(true));
            }
            loop {
                let sr = unsafe { regs.sr().read() };
                if sr.tifre() {
                    return Err(Error::Framing);
                }
                if sr.ovr() {
                    return Err(Error::Overrun);
                }
                if sr.crce() {
                    return Err(Error::Crc);
                }
                if !sr.txp() {
                    // loop waiting for TXE
                }
            }
        }

        Ok(())
    }
}

impl<'d, T: Instance> embedded_hal::blocking::spi::Transfer<u16> for Spi<'d, T, NoDma> {
    type Error = Error;

    fn transfer<'w>(&mut self, words: &'w mut [u16]) -> Result<&'w [u16], Self::Error> {
        Self::set_word_size(WordSize::SixteenBit);
        let regs = T::regs();

        for word in words.iter_mut() {
            while unsafe { !regs.sr().read().txp() } {
                // spin
            }
            unsafe {
                let txdr = regs.txdr().ptr() as *mut u16;
                ptr::write_volatile(txdr, *word);
                regs.cr1().modify(|reg| reg.set_cstart(true));
            }

            loop {
                let sr = unsafe { regs.sr().read() };

                if sr.rxp() {
                    break;
                }
                if sr.tifre() {
                    return Err(Error::Framing);
                }
                if sr.ovr() {
                    return Err(Error::Overrun);
                }
                if sr.crce() {
                    return Err(Error::Crc);
                }
            }

            unsafe {
                let rxdr = regs.rxdr().ptr() as *const u16;
                *word = ptr::read_volatile(rxdr);
            }
            let sr = unsafe { regs.sr().read() };
            if sr.tifre() {
                return Err(Error::Framing);
            }
            if sr.ovr() {
                return Err(Error::Overrun);
            }
            if sr.crce() {
                return Err(Error::Crc);
            }
        }

        Ok(words)
    }
}

impl<'d, T: Instance, Tx, Rx> traits::Spi<u8> for Spi<'d, T, Tx, Rx> {
    type Error = super::Error;
}

impl<'d, T: Instance, Tx: TxDmaChannel<T>, Rx> traits::Write<u8> for Spi<'d, T, Tx, Rx> {
    #[rustfmt::skip]
    type WriteFuture<'a> where Self: 'a = impl Future<Output = Result<(), Self::Error>> + 'a;

    fn write<'a>(&'a mut self, data: &'a [u8]) -> Self::WriteFuture<'a> {
        self.write_dma_u8(data)
    }
}

impl<'d, T: Instance, Tx: TxDmaChannel<T>, Rx: RxDmaChannel<T>> traits::Read<u8>
    for Spi<'d, T, Tx, Rx>
{
    #[rustfmt::skip]
    type ReadFuture<'a> where Self: 'a = impl Future<Output = Result<(), Self::Error>> + 'a;

    fn read<'a>(&'a mut self, data: &'a mut [u8]) -> Self::ReadFuture<'a> {
        self.read_dma_u8(data)
    }
}

impl<'d, T: Instance, Tx: TxDmaChannel<T>, Rx: RxDmaChannel<T>> traits::FullDuplex<u8>
    for Spi<'d, T, Tx, Rx>
{
    #[rustfmt::skip]
    type WriteReadFuture<'a> where Self: 'a = impl Future<Output = Result<(), Self::Error>> + 'a;

    fn read_write<'a>(
        &'a mut self,
        read: &'a mut [u8],
        write: &'a [u8],
    ) -> Self::WriteReadFuture<'a> {
        self.read_write_dma_u8(read, write)
    }
}