uniffi::setup_scaffolding!();

mod backdrop;
pub mod scenes;

use std::path::Path;

// A simple test function to ensure the Kotlin <-> Rust bridge is working.
#[uniffi::export]
pub fn oxygen_greeting(name: String) -> String {
    format!("Hello, {}! Oxygen Native Core is active.", name)
}

/// Why a runner call failed, in OxygenFlow's words.
#[derive(Debug, uniffi::Error)]
pub enum RunnerError {
    Failed { reason: String },
}

impl std::fmt::Display for RunnerError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            RunnerError::Failed { reason } => f.write_str(reason),
        }
    }
}

impl std::error::Error for RunnerError {}

fn failed(e: anyhow::Error) -> RunnerError {
    RunnerError::Failed { reason: format!("{e:#}") }
}

/// The phone as an OxygenFlow runner (oxygenhub-android#8): OxygenFlow's
/// own runner, built into the app, offering only the WASM tier. `home` is
/// the app's directory for it; `register` keeps the runner's credential
/// there (runner.toml), as `flow runner register` does on a host.
#[uniffi::export]
pub fn runner_register(home: String, hub: String, token: String, name: String) -> Result<String, RunnerError> {
    let h = flow::home::Home::locate(Some(Path::new(&home))).map_err(failed)?;
    let r = flow::runner::register(&h, &hub, &token, &name, None, vec!["android".into()]).map_err(failed)?;
    Ok(r.name)
}

/// Whether `home` holds a registration, and so can serve.
#[uniffi::export]
pub fn runner_is_registered(home: String) -> bool {
    Path::new(&home).join(flow::home::RUNNER_TOML).is_file()
}

/// Claim and run jobs until [`runner_stop`] drains the runner: returns
/// once the jobs it holds are done and reported. Blocks, so call it from
/// a thread of its own (the app's runner service).
#[uniffi::export]
pub fn runner_serve(home: String) -> Result<(), RunnerError> {
    let h = flow::home::Home::locate(Some(Path::new(&home))).map_err(failed)?;
    flow::runner::serve_embedded(&h).map_err(failed)
}

/// Drain the runner: claim nothing more, finish and report what it
/// holds, then [`runner_serve`] returns. For leaving the charger or the
/// allowed network, or the owner stopping it.
#[uniffi::export]
pub fn runner_stop() {
    flow::runner::stop();
}

/// Leave (oxygenflow#76): claim nothing more, and hand the jobs it holds
/// back to the hub, which gives them to another runner ahead of new work;
/// [`runner_serve`] then returns. With `notice_secs`, a job the hub expects
/// to finish within the notice finishes first (its checkpoint saved if
/// not). 0 for leaving the allowed network, where finishing would use the
/// network the owner ruled out; a minute for leaving the charger.
#[uniffi::export]
pub fn runner_leave(reason: String, notice_secs: u64) {
    flow::runner::leave_within(&reason, std::time::Duration::from_secs(notice_secs));
}

/// The tiers this phone offers (the WASM tier), and why not the others.
#[uniffi::export]
pub fn runner_tiers(home: String) -> Vec<String> {
    let Ok(h) = flow::home::Home::locate(Some(Path::new(&home))) else { return vec![] };
    match flow::runner::tiers(&h) {
        Ok((have, _)) => have,
        Err(_) => vec![],
    }
}

/// A new X25519 secret for this phone's alerts (#16), to keep wrapped by
/// the Android Keystore.
#[uniffi::export]
pub fn alert_new_secret() -> Vec<u8> {
    flow_core::alert::new_secret().to_vec()
}

/// The public key of an alert secret, for the hub; empty for a secret that
/// is not 32 bytes.
#[uniffi::export]
pub fn alert_public_key(secret: Vec<u8>) -> Vec<u8> {
    <[u8; 32]>::try_from(secret.as_slice()).map(|s| flow_core::alert::public_key(&s).to_vec()).unwrap_or_default()
}

/// Open an alert the hub sealed to this phone; `None` when it was not
/// sealed to `secret` or was changed on the way.
#[uniffi::export]
pub fn alert_open(secret: Vec<u8>, sealed: Vec<u8>) -> Option<Vec<u8>> {
    let s = <[u8; 32]>::try_from(secret.as_slice()).ok()?;
    flow_core::alert::open(&s, &sealed)
}