use embassy_futures::select::{select3, Either3};
use embassy_net_driver_channel as ch;
use embassy_sync::pubsub::PubSubBehavior;

use crate::mac::event::Events;
use crate::mac::ioctl::{IoctlState, PendingIoctl};
use crate::mac::MTU;
use crate::sub::mac::Mac;

pub struct Runner<'a> {
    ch: ch::Runner<'a, MTU>,
    mac: Mac,

    ioctl_state: &'a IoctlState,
    ioctl_id: u16,
    sdpcm_seq: u8,
    sdpcm_seq_max: u8,

    events: &'a Events,
}

impl<'a> Runner<'a> {
    pub(crate) fn new(ch: ch::Runner<'a, MTU>, mac: Mac, ioctl_state: &'a IoctlState, events: &'a Events) -> Self {
        Self {
            ch,
            mac,
            ioctl_state,
            ioctl_id: 0,
            sdpcm_seq: 0,
            sdpcm_seq_max: 1,
            events,
        }
    }

    pub(crate) async fn init(&mut self, firmware: &[u8]) {
        self.bus.init().await;

        #[cfg(feature = "firmware-logs")]
        self.log_init().await;

        debug!("wifi init done");
    }

    pub async fn run(mut self) -> ! {
        let mut buf = [0; 512];
        loop {
            #[cfg(feature = "firmware-logs")]
            self.log_read().await;

            if self.has_credit() {
                let ioctl = self.ioctl_state.wait_pending();
                let tx = self.ch.tx_buf();
                let ev = self.bus.wait_for_event();

                match select3(ioctl, tx, ev).await {
                    Either3::First(PendingIoctl {
                        buf: iobuf,
                        kind,
                        cmd,
                        iface,
                    }) => {
                        self.send_ioctl(kind, cmd, iface, unsafe { &*iobuf }).await;
                        self.check_status(&mut buf).await;
                    }
                    Either3::Second(packet) => {
                        trace!("tx pkt {:02x}", Bytes(&packet[..packet.len().min(48)]));

                        let mut buf = [0; 512];
                        let buf8 = slice8_mut(&mut buf);

                        // There MUST be 2 bytes of padding between the SDPCM and BDC headers.
                        // And ONLY for data packets!
                        // No idea why, but the firmware will append two zero bytes to the tx'd packets
                        // otherwise. If the packet is exactly 1514 bytes (the max MTU), this makes it
                        // be oversized and get dropped.
                        // WHD adds it here https://github.com/Infineon/wifi-host-driver/blob/c04fcbb6b0d049304f376cf483fd7b1b570c8cd5/WiFi_Host_Driver/src/include/whd_sdpcm.h#L90
                        // and adds it to the header size her https://github.com/Infineon/wifi-host-driver/blob/c04fcbb6b0d049304f376cf483fd7b1b570c8cd5/WiFi_Host_Driver/src/whd_sdpcm.c#L597
                        // ¯\_(ツ)_/¯
                        const PADDING_SIZE: usize = 2;
                        let total_len = SdpcmHeader::SIZE + PADDING_SIZE + BdcHeader::SIZE + packet.len();

                        let seq = self.sdpcm_seq;
                        self.sdpcm_seq = self.sdpcm_seq.wrapping_add(1);

                        let sdpcm_header = SdpcmHeader {
                            len: total_len as u16, // TODO does this len need to be rounded up to u32?
                            len_inv: !total_len as u16,
                            sequence: seq,
                            channel_and_flags: CHANNEL_TYPE_DATA,
                            next_length: 0,
                            header_length: (SdpcmHeader::SIZE + PADDING_SIZE) as _,
                            wireless_flow_control: 0,
                            bus_data_credit: 0,
                            reserved: [0, 0],
                        };

                        let bdc_header = BdcHeader {
                            flags: BDC_VERSION << BDC_VERSION_SHIFT,
                            priority: 0,
                            flags2: 0,
                            data_offset: 0,
                        };
                        trace!("tx {:?}", sdpcm_header);
                        trace!("    {:?}", bdc_header);

                        buf8[0..SdpcmHeader::SIZE].copy_from_slice(&sdpcm_header.to_bytes());
                        buf8[SdpcmHeader::SIZE + PADDING_SIZE..][..BdcHeader::SIZE]
                            .copy_from_slice(&bdc_header.to_bytes());
                        buf8[SdpcmHeader::SIZE + PADDING_SIZE + BdcHeader::SIZE..][..packet.len()]
                            .copy_from_slice(packet);

                        let total_len = (total_len + 3) & !3; // round up to 4byte

                        trace!("    {:02x}", Bytes(&buf8[..total_len.min(48)]));

                        self.bus.wlan_write(&buf[..(total_len / 4)]).await;
                        self.ch.tx_done();
                        self.check_status(&mut buf).await;
                    }
                    Either3::Third(()) => {
                        self.handle_irq(&mut buf).await;
                    }
                }
            } else {
                warn!("TX stalled");
                self.bus.wait_for_event().await;
                self.handle_irq(&mut buf).await;
            }
        }
    }

    /// Wait for IRQ on F2 packet available
    async fn handle_irq(&mut self, buf: &mut [u32; 512]) {
        // Receive stuff
        let irq = self.bus.read16(FUNC_BUS, REG_BUS_INTERRUPT).await;
        trace!("irq{}", FormatInterrupt(irq));

        if irq & IRQ_F2_PACKET_AVAILABLE != 0 {
            self.check_status(buf).await;
        }

        if irq & IRQ_DATA_UNAVAILABLE != 0 {
            // TODO what should we do here?
            warn!("IRQ DATA_UNAVAILABLE, clearing...");
            self.bus.write16(FUNC_BUS, REG_BUS_INTERRUPT, 1).await;
        }
    }

    /// Handle F2 events while status register is set
    async fn check_status(&mut self, buf: &mut [u32; 512]) {
        loop {
            let status = self.bus.status();
            trace!("check status{}", FormatStatus(status));

            if status & STATUS_F2_PKT_AVAILABLE != 0 {
                let len = (status & STATUS_F2_PKT_LEN_MASK) >> STATUS_F2_PKT_LEN_SHIFT;
                self.bus.wlan_read(buf, len).await;
                trace!("rx {:02x}", Bytes(&slice8_mut(buf)[..(len as usize).min(48)]));
                self.rx(&mut slice8_mut(buf)[..len as usize]);
            } else {
                break;
            }
        }
    }

    fn rx(&mut self, packet: &mut [u8]) {
        let Some((sdpcm_header, payload)) = SdpcmHeader::parse(packet) else {
            return;
        };

        self.update_credit(&sdpcm_header);

        let channel = sdpcm_header.channel_and_flags & 0x0f;

        match channel {
            CHANNEL_TYPE_CONTROL => {
                let Some((cdc_header, response)) = CdcHeader::parse(payload) else {
                    return;
                };
                trace!("    {:?}", cdc_header);

                if cdc_header.id == self.ioctl_id {
                    if cdc_header.status != 0 {
                        // TODO: propagate error instead
                        panic!("IOCTL error {}", cdc_header.status as i32);
                    }

                    self.ioctl_state.ioctl_done(response);
                }
            }
            CHANNEL_TYPE_EVENT => {
                let Some((_, bdc_packet)) = BdcHeader::parse(payload) else {
                    warn!("BDC event, incomplete header");
                    return;
                };

                let Some((event_packet, evt_data)) = EventPacket::parse(bdc_packet) else {
                    warn!("BDC event, incomplete data");
                    return;
                };

                const ETH_P_LINK_CTL: u16 = 0x886c; // HPNA, wlan link local tunnel, according to linux if_ether.h
                if event_packet.eth.ether_type != ETH_P_LINK_CTL {
                    warn!(
                        "unexpected ethernet type 0x{:04x}, expected Broadcom ether type 0x{:04x}",
                        event_packet.eth.ether_type, ETH_P_LINK_CTL
                    );
                    return;
                }
                const BROADCOM_OUI: &[u8] = &[0x00, 0x10, 0x18];
                if event_packet.hdr.oui != BROADCOM_OUI {
                    warn!(
                        "unexpected ethernet OUI {:02x}, expected Broadcom OUI {:02x}",
                        Bytes(&event_packet.hdr.oui),
                        Bytes(BROADCOM_OUI)
                    );
                    return;
                }
                const BCMILCP_SUBTYPE_VENDOR_LONG: u16 = 32769;
                if event_packet.hdr.subtype != BCMILCP_SUBTYPE_VENDOR_LONG {
                    warn!("unexpected subtype {}", event_packet.hdr.subtype);
                    return;
                }

                const BCMILCP_BCM_SUBTYPE_EVENT: u16 = 1;
                if event_packet.hdr.user_subtype != BCMILCP_BCM_SUBTYPE_EVENT {
                    warn!("unexpected user_subtype {}", event_packet.hdr.subtype);
                    return;
                }

                let evt_type = events::Event::from(event_packet.msg.event_type as u8);
                debug!(
                    "=== EVENT {:?}: {:?} {:02x}",
                    evt_type,
                    event_packet.msg,
                    Bytes(evt_data)
                );

                if self.events.mask.is_enabled(evt_type) {
                    let status = event_packet.msg.status;
                    let event_payload = match evt_type {
                        Event::ESCAN_RESULT if status == EStatus::PARTIAL => {
                            let Some((_, bss_info)) = ScanResults::parse(evt_data) else {
                                return;
                            };
                            let Some(bss_info) = BssInfo::parse(bss_info) else {
                                return;
                            };
                            events::Payload::BssInfo(*bss_info)
                        }
                        Event::ESCAN_RESULT => events::Payload::None,
                        _ => events::Payload::None,
                    };

                    // this intentionally uses the non-blocking publish immediate
                    // publish() is a deadlock risk in the current design as awaiting here prevents ioctls
                    // The `Runner` always yields when accessing the device, so consumers always have a chance to receive the event
                    // (if they are actively awaiting the queue)
                    self.events.queue.publish_immediate(events::Message::new(
                        Status {
                            event_type: evt_type,
                            status,
                        },
                        event_payload,
                    ));
                }
            }
            CHANNEL_TYPE_DATA => {
                let Some((_, packet)) = BdcHeader::parse(payload) else {
                    return;
                };
                trace!("rx pkt {:02x}", Bytes(&packet[..packet.len().min(48)]));

                match self.ch.try_rx_buf() {
                    Some(buf) => {
                        buf[..packet.len()].copy_from_slice(packet);
                        self.ch.rx_done(packet.len())
                    }
                    None => warn!("failed to push rxd packet to the channel."),
                }
            }
            _ => {}
        }
    }

    fn update_credit(&mut self, sdpcm_header: &SdpcmHeader) {
        if sdpcm_header.channel_and_flags & 0xf < 3 {
            let mut sdpcm_seq_max = sdpcm_header.bus_data_credit;
            if sdpcm_seq_max.wrapping_sub(self.sdpcm_seq) > 0x40 {
                sdpcm_seq_max = self.sdpcm_seq + 2;
            }
            self.sdpcm_seq_max = sdpcm_seq_max;
        }
    }

    fn has_credit(&self) -> bool {
        self.sdpcm_seq != self.sdpcm_seq_max && self.sdpcm_seq_max.wrapping_sub(self.sdpcm_seq) & 0x80 == 0
    }

    async fn send_ioctl(&mut self, kind: IoctlType, cmd: u32, iface: u32, data: &[u8]) {
        let mut buf = [0; 512];
        let buf8 = slice8_mut(&mut buf);

        let total_len = SdpcmHeader::SIZE + CdcHeader::SIZE + data.len();

        let sdpcm_seq = self.sdpcm_seq;
        self.sdpcm_seq = self.sdpcm_seq.wrapping_add(1);
        self.ioctl_id = self.ioctl_id.wrapping_add(1);

        let sdpcm_header = SdpcmHeader {
            len: total_len as u16, // TODO does this len need to be rounded up to u32?
            len_inv: !total_len as u16,
            sequence: sdpcm_seq,
            channel_and_flags: CHANNEL_TYPE_CONTROL,
            next_length: 0,
            header_length: SdpcmHeader::SIZE as _,
            wireless_flow_control: 0,
            bus_data_credit: 0,
            reserved: [0, 0],
        };

        let cdc_header = CdcHeader {
            cmd: cmd,
            len: data.len() as _,
            flags: kind as u16 | (iface as u16) << 12,
            id: self.ioctl_id,
            status: 0,
        };
        trace!("tx {:?}", sdpcm_header);
        trace!("    {:?}", cdc_header);

        buf8[0..SdpcmHeader::SIZE].copy_from_slice(&sdpcm_header.to_bytes());
        buf8[SdpcmHeader::SIZE..][..CdcHeader::SIZE].copy_from_slice(&cdc_header.to_bytes());
        buf8[SdpcmHeader::SIZE + CdcHeader::SIZE..][..data.len()].copy_from_slice(data);

        let total_len = (total_len + 3) & !3; // round up to 4byte

        trace!("    {:02x}", Bytes(&buf8[..total_len.min(48)]));

        self.bus.wlan_write(&buf[..total_len / 4]).await;
    }
}