use crate::model::Trojan;
use anyhow::{Result, bail};
use async_trait::async_trait;

/// A verified local proxy connection owned by a runtime probe session.
pub struct ProbeConnection<'a> {
    pub proxy_url: &'a str,
    pub certificate: &'a str,
}

#[async_trait]
pub trait ProbeSession: Send {
    fn connection(&self) -> ProbeConnection<'_>;
    async fn stop(self: Box<Self>);
}

#[async_trait]
pub trait Runtime: Send {
    /// Protection must be installed before durable enabled intent changes.
    async fn arm(&mut self) -> Result<()>;
    async fn apply(&mut self, connection: Option<&Trojan>, generation: u64) -> Result<()>;
    async fn block(&mut self) -> Result<()> {
        self.arm().await?;
        self.apply(None, 0).await
    }
    async fn maintain(&mut self, connection: Option<&Trojan>, generation: u64) -> Result<()> {
        self.apply(connection, generation).await
    }
    async fn probe(&mut self, _: &Trojan, _: u64) -> Result<Box<dyn ProbeSession>> {
        bail!("Protected diagnostic probes are unavailable in this runtime")
    }
    /// Called only after disabled intent has been durably recorded.
    async fn disable(&mut self) -> Result<()>;
    fn routing(&self) -> &str;
}

/// Allows managing saved subscriptions without claiming that host capture is available.
pub struct OfflineRuntime;
#[async_trait]
impl Runtime for OfflineRuntime {
    async fn arm(&mut self) -> Result<()> {
        bail!("Host networking is unavailable; install and start the Roentgen service")
    }
    async fn apply(&mut self, _: Option<&Trojan>, _: u64) -> Result<()> {
        bail!("Host networking is unavailable")
    }
    async fn disable(&mut self) -> Result<()> {
        Ok(())
    }
    fn routing(&self) -> &str {
        "unavailable"
    }
}