use crate::common::*;
use crate::runtime::{errors::*, *};

pub fn random_controller_id() -> ControllerId {
    type Bytes8 = [u8; std::mem::size_of::<ControllerId>()];
    let mut bytes = Bytes8::default();
    getrandom::getrandom(&mut bytes).unwrap();
    unsafe { std::mem::transmute::<Bytes8, ControllerId>(bytes) }
}

impl Default for Unconfigured {
    fn default() -> Self {
        let controller_id = random_controller_id();
        Self { controller_id }
    }
}
impl Default for Connector {
    fn default() -> Self {
        Self::Unconfigured(Unconfigured::default())
    }
}
impl Connector {
    /// Configure the Connector with the given Pdl description.
    pub fn configure(&mut self, pdl: &[u8]) -> Result<(), ConfigErr> {
        use ConfigErr::*;
        let controller_id = match self {
            Connector::Configured(_) => return Err(AlreadyConfigured),
            Connector::Connected(_) => return Err(AlreadyConnected),
            Connector::Unconfigured(Unconfigured { controller_id }) => *controller_id,
        };
        let protocol_description = Arc::new(ProtocolD::parse(pdl).map_err(ParseErr)?);
        let proto_maybe_bindings = protocol_description
            .main_interface_polarities()
            .into_iter()
            .zip(std::iter::repeat(None))
            .collect();
        let configured = Configured { controller_id, protocol_description, proto_maybe_bindings };
        *self = Connector::Configured(configured);
        Ok(())
    }

    /// Bind the (configured) connector's port corresponding to the
    pub fn bind_port(
        &mut self,
        proto_port_index: usize,
        binding: PortBinding,
    ) -> Result<(), PortBindErr> {
        use PortBindErr::*;
        match self {
            Connector::Unconfigured { .. } => Err(NotConfigured),
            Connector::Connected(_) => Err(AlreadyConnected),
            Connector::Configured(configured) => {
                match configured.proto_maybe_bindings.get_mut(proto_port_index) {
                    None => Err(IndexOutOfBounds),
                    Some((_polarity, Some(_))) => Err(PortAlreadyBound),
                    Some((_polarity, x @ None)) => {
                        *x = Some(binding);
                        Ok(())
                    }
                }
            }
        }
    }
    pub fn connect(&mut self, timeout: Duration) -> Result<(), ConnectErr> {
        let deadline = Instant::now() + timeout;
        use ConnectErr::*;
        let configured = match self {
            Connector::Unconfigured { .. } => return Err(NotConfigured),
            Connector::Connected(_) => return Err(AlreadyConnected),
            Connector::Configured(configured) => configured,
        };
        // 1. Unwrap bindings or err
        let bound_proto_interface: Vec<(_, _)> = configured
            .proto_maybe_bindings
            .iter()
            .copied()
            .enumerate()
            .map(|(native_index, (polarity, maybe_binding))| {
                Ok((maybe_binding.ok_or(PortNotBound { native_index })?, polarity))
            })
            .collect::<Result<Vec<(_, _)>, ConnectErr>>()?;
        let (controller, native_interface) = Controller::connect(
            configured.controller_id,
            configured.protocol_description.clone(),
            &bound_proto_interface[..],
            deadline,
        )?;
        *self = Connector::Connected(Connected {
            native_interface,
            sync_batches: vec![Default::default()],
            controller,
        });
        Ok(())
    }

    pub fn put(&mut self, native_port_index: usize, payload: Payload) -> Result<(), PortOpErr> {
        use PortOpErr::*;
        let connected = match self {
            Connector::Connected(connected) => connected,
            _ => return Err(NotConnected),
        };
        let (ekey, native_polarity) =
            *connected.native_interface.get(native_port_index).ok_or(IndexOutOfBounds)?;
        if native_polarity != Putter {
            return Err(WrongPolarity);
        }
        let sync_batch = connected.sync_batches.iter_mut().last().unwrap();
        if sync_batch.puts.contains_key(&ekey) {
            return Err(DuplicateOperation);
        }
        sync_batch.puts.insert(ekey, payload);
        Ok(())
    }

    pub fn get(&mut self, native_port_index: usize) -> Result<(), PortOpErr> {
        use PortOpErr::*;
        let connected = match self {
            Connector::Connected(connected) => connected,
            _ => return Err(NotConnected),
        };
        let (ekey, native_polarity) =
            *connected.native_interface.get(native_port_index).ok_or(IndexOutOfBounds)?;
        if native_polarity != Getter {
            return Err(WrongPolarity);
        }
        let sync_batch = connected.sync_batches.iter_mut().last().unwrap();
        if sync_batch.gets.contains(&ekey) {
            return Err(DuplicateOperation);
        }
        sync_batch.gets.insert(ekey);
        Ok(())
    }
    pub fn next_batch(&mut self) -> Result<usize, ()> {
        let connected = match self {
            Connector::Connected(connected) => connected,
            _ => return Err(()),
        };
        connected.sync_batches.push(SyncBatch::default());
        Ok(connected.sync_batches.len() - 1)
    }

    pub fn sync(&mut self, timeout: Duration) -> Result<usize, SyncErr> {
        let deadline = Instant::now() + timeout;
        use SyncErr::*;
        let connected = match self {
            Connector::Connected(connected) => connected,
            _ => return Err(NotConnected),
        };

        // do the synchronous round!
        connected.controller.sync_round(deadline, Some(connected.sync_batches.drain(..)))?;
        connected.sync_batches.push(SyncBatch::default());

        let mono_n = connected.controller.inner.mono_n.as_mut().unwrap();
        let result = mono_n.result.as_mut().unwrap();
        Ok(result.0)
    }

    pub fn read_gotten(&self, native_port_index: usize) -> Result<&[u8], ReadGottenErr> {
        use ReadGottenErr::*;
        let connected = match self {
            Connector::Connected(connected) => connected,
            _ => return Err(NotConnected),
        };
        let &(key, polarity) =
            connected.native_interface.get(native_port_index).ok_or(IndexOutOfBounds)?;
        if polarity != Getter {
            return Err(WrongPolarity);
        }
        let mono_n = connected.controller.inner.mono_n.as_ref().expect("controller has no mono_n?");
        let result = mono_n.result.as_ref().ok_or(NoPreviousRound)?;
        let payload = result.1.get(&key).ok_or(DidntGet)?;
        Ok(payload)
    }
}