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pub mod task_manager;

use crate::{http::DynHttpClient, os::TtyBridge, WasiTtyState};

pub use self::task_manager::{SpawnType, SpawnedMemory, VirtualTaskManager};

use std::{
    fmt,
    sync::{Arc, Mutex},
};

use derivative::Derivative;
use virtual_net::{DynVirtualNetworking, VirtualNetworking};

/// Represents an implementation of the WASI runtime - by default everything is
/// unimplemented.
#[allow(unused_variables)]
pub trait WasiRuntime
where
    Self: fmt::Debug + Sync,
{
    /// Provides access to all the networking related functions such as sockets.
    /// By default networking is not implemented.
    fn networking(&self) -> &DynVirtualNetworking;

    /// Retrieve the active [`VirtualTaskManager`].
    fn task_manager(&self) -> &Arc<dyn VirtualTaskManager>;

    /// Get a [`wasmer::Engine`] for module compilation.
    fn engine(&self) -> Option<wasmer::Engine> {
        None
    }

    /// Create a new [`wasmer::Store`].
    fn new_store(&self) -> wasmer::Store {
        cfg_if::cfg_if! {
            if #[cfg(feature = "sys")] {
                if let Some(engine) = self.engine() {
                    wasmer::Store::new(engine)
                } else {
                    wasmer::Store::default()
                }
            } else {
                wasmer::Store::default()
            }
        }
    }

    /// Returns a HTTP client
    fn http_client(&self) -> Option<&DynHttpClient> {
        None
    }

    /// Get access to the TTY used by the environment.
    fn tty(&self) -> Option<&(dyn TtyBridge + Send + Sync)> {
        None
    }
}

#[derive(Debug, Default)]
pub struct DefaultTty {
    state: Mutex<WasiTtyState>,
}

impl TtyBridge for DefaultTty {
    fn reset(&self) {
        let mut state = self.state.lock().unwrap();
        state.echo = false;
        state.line_buffered = false;
        state.line_feeds = false
    }

    fn tty_get(&self) -> WasiTtyState {
        let state = self.state.lock().unwrap();
        state.clone()
    }

    fn tty_set(&self, tty_state: WasiTtyState) {
        let mut state = self.state.lock().unwrap();
        *state = tty_state;
    }
}

#[derive(Clone, Derivative)]
#[derivative(Debug)]
pub struct PluggableRuntime {
    pub rt: Arc<dyn VirtualTaskManager>,
    pub networking: DynVirtualNetworking,
    pub http_client: Option<DynHttpClient>,
    pub engine: Option<wasmer::Engine>,
    #[derivative(Debug = "ignore")]
    pub tty: Option<Arc<dyn TtyBridge + Send + Sync>>,
}

impl PluggableRuntime {
    pub fn new(rt: Arc<dyn VirtualTaskManager>) -> Self {
        // TODO: the cfg flags below should instead be handled by separate implementations.
        cfg_if::cfg_if! {
            if #[cfg(feature = "host-vnet")] {
                let networking = Arc::new(virtual_net::host::LocalNetworking::default());
            } else {
                let networking = Arc::new(virtual_net::UnsupportedVirtualNetworking::default());
            }
        }
        cfg_if::cfg_if! {
            if #[cfg(feature = "host-reqwest")] {
                let http_client = Some(Arc::new(
                    crate::http::reqwest::ReqwestHttpClient::default()) as DynHttpClient
                );
            } else {
                let http_client = None;
            }
        }

        Self {
            rt,
            networking,
            http_client,
            engine: None,
            tty: None,
        }
    }

    pub fn set_networking_implementation<I>(&mut self, net: I)
    where
        I: VirtualNetworking + Sync,
    {
        self.networking = Arc::new(net)
    }

    pub fn set_engine(&mut self, engine: Option<wasmer::Engine>) {
        self.engine = engine;
    }

    pub fn set_tty(&mut self, tty: Arc<dyn TtyBridge + Send + Sync>) {
        self.tty = Some(tty);
    }
}

impl WasiRuntime for PluggableRuntime {
    fn networking(&self) -> &DynVirtualNetworking {
        &self.networking
    }

    fn http_client(&self) -> Option<&DynHttpClient> {
        self.http_client.as_ref()
    }

    fn engine(&self) -> Option<wasmer::Engine> {
        self.engine.clone()
    }

    fn task_manager(&self) -> &Arc<dyn VirtualTaskManager> {
        &self.rt
    }

    fn tty(&self) -> Option<&(dyn TtyBridge + Send + Sync)> {
        self.tty.as_deref()
    }
}