//! The launch sequence, as an explicit state machine.
//!
//! # Why this exists
//!
//! The launcher used to make the user perform OpenFUT's internal launch order by
//! hand: start LSX, start autopatch, run pre-launch checks, "Arm client", then
//! press a button called *Start Services & Launch Game*. Every one of those is an
//! implementation detail of how FIFA 17 is persuaded to talk to OpenFUT, and
//! getting the order wrong produced failures that surfaced much later as "the
//! game crashed" — autopatch started before `ptrace_scope` was 0 silently does
//! nothing at all.
//!
//! So the sequence lives here, once, and the UI renders it. One button.
//!
//! # Ordering, and where it deviates from the obvious
//!
//! Client preparation (`arm`) runs BEFORE autopatch, not after: autopatch writes
//! `/proc/<FIFA17.exe>/mem`, which Yama forbids until arming sets
//! `kernel.yama.ptrace_scope=0`. Starting autopatch first would "succeed" and
//! then quietly fail to patch anything.
//!
//! # Idempotence
//!
//! Every step asks what is already true before acting. A healthy service is
//! reused, never restarted; client preparation is skipped when the checks it
//! would repair already pass, which also avoids an unnecessary Polkit prompt.
//!
//! # Testability
//!
//! The effects — spawning services, elevating for arming, writing the hook
//! config, starting the game — sit behind [`LaunchOps`]. [`run_sequence`] is
//! therefore a pure decision procedure over observed state, and the sequencing
//! rules that matter (don't launch after a failed step, don't restart healthy
//! services, don't kill what we didn't start) are unit-testable without a FIFA
//! install, a Polkit agent, or root.

use std::sync::Arc;

use crate::config::LauncherConfig;
use crate::fifa17_capability::Fifa17ClientCapabilities;
use crate::local_services::{
    CapabilityWiring, Ensured, Service, ServiceRuntime, ServiceSupervisor, SpawnSpec,
};
use crate::logs::LogBuffer;
use crate::preflight::{self, Check, State};
use parking_lot::Mutex;

/// Where the launch sequence is. Rendered directly by the UI; the UI never
/// coordinates services itself.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub enum Phase {
    /// Nothing in flight. Readiness still comes from observed state, not from
    /// having been here.
    #[default]
    Idle,
    /// Looking at the world: checks + service + hook state.
    Checking,
    /// Elevated client preparation in flight (this is what shows a password
    /// prompt).
    PreparingClient,
    StartingServices,
    /// Re-checking after repair, before committing to a launch.
    Validating,
    Launching,
    /// FIFA is up. Left when the process exits.
    Running,
    Failed,
}

impl Phase {
    /// Whether a launch is under way, i.e. the primary button must not start a
    /// second one.
    pub fn busy(self) -> bool {
        matches!(
            self,
            Phase::Checking
                | Phase::PreparingClient
                | Phase::StartingServices
                | Phase::Validating
                | Phase::Launching
        )
    }
}

/// One step of the sequence, in execution order.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum Step {
    Server,
    ClientFiles,
    ClientPreparation,
    Lsx,
    Autopatch,
    FinalChecks,
    Game,
}

impl Step {
    /// User-facing name. Deliberately not the internal vocabulary: "arm" is
    /// implementation terminology and never appears in the normal flow.
    pub fn label(self) -> &'static str {
        match self {
            Step::Server => "OpenFUT server",
            Step::ClientFiles => "Client files",
            Step::ClientPreparation => "Client preparation",
            Step::Lsx => "LSX",
            Step::Autopatch => "Autopatch",
            Step::FinalChecks => "Final checks",
            Step::Game => "FIFA 17",
        }
    }
}

/// How a step ended. `Skipped` is a success that did nothing — the state it
/// would have produced was already true.
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum Outcome {
    Done(String),
    Skipped(String),
    Failed(String),
}

impl Outcome {
    pub fn ok(&self) -> bool {
        !matches!(self, Outcome::Failed(_))
    }

    pub fn detail(&self) -> &str {
        match self {
            Outcome::Done(d) | Outcome::Skipped(d) | Outcome::Failed(d) => d,
        }
    }
}

/// Everything the UI needs to render the launch surface.
#[derive(Debug, Clone, Default)]
pub struct LaunchState {
    pub phase: Phase,
    /// Steps attempted by the most recent run, in order.
    pub steps: Vec<(Step, Outcome)>,
    /// One-line reason the run failed, for the top of the failure card. The
    /// per-step detail carries the specifics.
    pub failure: Option<String>,
    /// The most recent preflight results and when they were taken. Cached
    /// because the checks open sockets with timeouts and cannot run per frame.
    pub checks: Option<Vec<Check>>,
    pub checks_age: Option<std::time::Instant>,
}

impl LaunchState {
    fn begin(&mut self, phase: Phase) {
        self.phase = phase;
        self.steps.clear();
        self.failure = None;
    }

    fn record(&mut self, step: Step, outcome: Outcome) {
        if let Outcome::Failed(reason) = &outcome {
            self.failure = Some(format!("{}: {reason}", step.label()));
        }
        self.steps.push((step, outcome));
    }
}

/// The effects the sequence performs. Implemented for real by [`RealOps`] and
/// substituted in tests.
pub trait LaunchOps {
    /// Confirm the configured OpenFUT server is answering AND select the account
    /// for this session. The server is remote by design, so this is a network
    /// fact, never "is something local up". Returns a user-facing summary.
    fn connect_server(&mut self) -> Result<String, String>;
    /// Version.dll + a readable openfut.cfg. `Err` is a hard stop: without them
    /// FIFA talks to EA, not OpenFUT.
    fn ensure_client_files(&mut self) -> Result<String, String>;
    /// Which of the arming-repairable checks are currently failing.
    fn run_checks(&mut self) -> Vec<Check>;
    /// Elevated client preparation (`arm`). Returns what it changed.
    fn prepare_client(&mut self) -> Result<Vec<String>, String>;
    fn ensure_service(&mut self, service: Service) -> Result<Ensured, String>;
    fn start_game(&mut self) -> Result<(), String>;
}

/// Checks that client preparation is able to repair. A failure in any of these
/// means "prepare the client", not "give up".
fn preparation_repairs(check: &Check) -> bool {
    const REPAIRABLE: [&str; 3] = [
        "ptrace_scope (autopatch)",
        "EA redirector IP is redirected",
        "EA hostnames point at OpenFUT",
    ];
    REPAIRABLE.contains(&check.name.as_str())
}

/// Run the whole sequence, publishing progress into `state` as it goes.
///
/// Returns whether FIFA was started. Stops at the first failed step: launching
/// into a known-broken client produces a session that fails minutes later with
/// no message naming the cause, which is precisely the failure mode this
/// launcher exists to prevent.
pub fn run_sequence(ops: &mut dyn LaunchOps, state: &Arc<Mutex<LaunchState>>) -> bool {
    macro_rules! step {
        ($phase:expr, $step:expr, $body:expr) => {{
            state.lock().phase = $phase;
            let outcome: Outcome = $body;
            let ok = outcome.ok();
            state.lock().record($step, outcome);
            if !ok {
                state.lock().phase = Phase::Failed;
                return false;
            }
        }};
    }

    state.lock().begin(Phase::Checking);

    // ── The server, which is remote and not ours to start ────────────────────
    step!(Phase::Checking, Step::Server, {
        match ops.connect_server() {
            Ok(detail) => Outcome::Done(detail),
            Err(e) => Outcome::Failed(e),
        }
    });

    // ── The hook the game loads, reconciled with the current settings ────────
    step!(Phase::Checking, Step::ClientFiles, {
        match ops.ensure_client_files() {
            Ok(detail) => Outcome::Done(detail),
            Err(e) => Outcome::Failed(e),
        }
    });

    // ── Client preparation, only if something it repairs is broken ───────────
    let checks = ops.run_checks();
    let broken: Vec<String> = checks
        .iter()
        .filter(|c| c.state == State::Fail && preparation_repairs(c))
        .map(|c| c.name.clone())
        .collect();
    {
        let mut guard = state.lock();
        guard.checks = Some(checks);
        guard.checks_age = Some(std::time::Instant::now());
    }
    step!(Phase::PreparingClient, Step::ClientPreparation, {
        if broken.is_empty() {
            Outcome::Skipped("already prepared".into())
        } else {
            match ops.prepare_client() {
                Ok(changes) => Outcome::Done(format!("{} change(s) applied", changes.len())),
                Err(e) => Outcome::Failed(e),
            }
        }
    });

    // ── Companion services, in dependency order ─────────────────────────────
    for (service, step) in [
        (Service::Lsx, Step::Lsx),
        (Service::Autopatch, Step::Autopatch),
    ] {
        step!(Phase::StartingServices, step, {
            match ops.ensure_service(service) {
                Ok(Ensured::Reused) => Outcome::Skipped("already running".into()),
                Ok(Ensured::Started) => Outcome::Done("started".into()),
                Err(e) => Outcome::Failed(e),
            }
        });
    }

    // ── Validate what the repairs were supposed to fix ──────────────────────
    step!(Phase::Validating, Step::FinalChecks, {
        let checks = ops.run_checks();
        let failed: Vec<String> = checks
            .iter()
            .filter(|c| c.state == State::Fail)
            .map(|c| c.name.clone())
            .collect();
        {
            let mut guard = state.lock();
            guard.checks = Some(checks);
            guard.checks_age = Some(std::time::Instant::now());
        }
        if failed.is_empty() {
            Outcome::Done("all checks pass".into())
        } else {
            Outcome::Failed(format!("still failing: {}", failed.join(", ")))
        }
    });

    step!(Phase::Launching, Step::Game, {
        match ops.start_game() {
            Ok(()) => Outcome::Done("started".into()),
            Err(e) => Outcome::Failed(e),
        }
    });

    state.lock().phase = Phase::Running;
    true
}

/// Observe the world without changing it, for the status rows on open and after
/// a settings change. Shares [`run_sequence`]'s notion of what "ready" means so
/// the two cannot drift apart.
pub fn refresh_checks(ops: &mut dyn LaunchOps, state: &Arc<Mutex<LaunchState>>) {
    state.lock().phase = Phase::Checking;
    let checks = ops.run_checks();
    let mut guard = state.lock();
    guard.checks = Some(checks);
    guard.checks_age = Some(std::time::Instant::now());
    guard.phase = Phase::Idle;
}

/// What happens to launcher-started services when FIFA exits.
///
/// Exists so the answer is a stated policy rather than an oversight. The shipped
/// value stops nothing:
///
/// * The companion services are reusable across launches — LSX has to be holding
///   :4216 before FIFA dials it, and the next launch would only start them again.
/// * A service the launcher did NOT start is never in the stop list under any
///   value of this policy.
///
/// Client preparation is deliberately absent, and is never reverted: it is host
/// state (`ptrace_scope`, a DNAT, `/etc/hosts`) that `client_arm.sh` also leaves
/// set and that every subsequent launch needs. A flag for it would be a flag
/// nothing honours.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub struct CleanupPolicy {
    pub stop_launcher_started_services: bool,
}

/// Which services cleanup is allowed to stop after `FIFA` exits: only ones this
/// launcher started, and only if the policy says so.
pub fn services_to_stop(
    policy: CleanupPolicy,
    runtimes: &[(Service, ServiceRuntime)],
) -> Vec<Service> {
    if !policy.stop_launcher_started_services {
        return Vec::new();
    }
    runtimes
        .iter()
        .filter(|(_, r)| r.running && r.started_by_launcher)
        .map(|(s, _)| *s)
        .collect()
}

/// Summary of one dependency for the main card.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum Readiness {
    Ready,
    Busy,
    Attention,
    /// Never looked, or the answer is stale. Never rendered as Ready.
    Unknown,
}

/// Client-integration readiness from the cached checks. `Unknown` until a run has
/// actually happened: "we did not look" must not look like "we looked and it was
/// fine".
pub fn client_integration(state: &LaunchState) -> Readiness {
    if matches!(state.phase, Phase::PreparingClient) {
        return Readiness::Busy;
    }
    match &state.checks {
        None => Readiness::Unknown,
        Some(checks) => {
            let relevant: Vec<&Check> = checks.iter().filter(|c| preparation_repairs(c)).collect();
            if relevant.iter().any(|c| c.state == State::Fail) {
                Readiness::Attention
            } else if relevant.iter().all(|c| c.state == State::Skipped) {
                // Nothing configured to check, so nothing was verified.
                Readiness::Unknown
            } else {
                Readiness::Ready
            }
        }
    }
}

/// Overall readiness for the card's headline pill. Anything short of every
/// dependency being observed-good is not Ready.
pub fn overall(
    phase: Phase,
    server: Readiness,
    integration: Readiness,
    services: Readiness,
    hook: Readiness,
) -> Readiness {
    if phase == Phase::Running {
        return Readiness::Ready;
    }
    if phase.busy() {
        return Readiness::Busy;
    }
    let parts = [server, integration, services, hook];
    if parts.contains(&Readiness::Attention) {
        Readiness::Attention
    } else if parts.contains(&Readiness::Unknown) {
        Readiness::Unknown
    } else {
        Readiness::Ready
    }
}

/// [`LaunchOps`] against the actual machine.
///
/// Holds a snapshot of the config: a launch must not change its mind halfway
/// through because the user edited a field while it ran.
pub struct RealOps {
    config: LauncherConfig,
    services: Arc<Mutex<ServiceSupervisor>>,
    logs: Arc<Mutex<LogBuffer>>,
    caps: Arc<Mutex<Fifa17ClientCapabilities>>,
    state: Arc<Mutex<LaunchState>>,
}

impl RealOps {
    fn say(&self, message: impl Into<String>) {
        self.logs.lock().push(message.into());
    }
}

impl LaunchOps for RealOps {
    fn connect_server(&mut self) -> Result<String, String> {
        self.config.validate_server()?;
        if preflight::backend_reachable(&self.config).state == State::Fail {
            return Err(format!(
                "{} is not answering — is the OpenFUT server running?",
                self.config.openfut_server_host
            ));
        }
        // Selecting the account is part of connecting: LSX and FIFA both
        // authenticate as this persona, and a launch with the wrong one produces
        // a session that looks fine and belongs to nobody.
        let account = crate::account_sync::sync(&self.config)?;
        self.say(format!(
            "[launcher] account synchronized: {}/{} FUT-coins={} unopened-packs={}",
            account.persona_id, account.persona_name, account.coins, account.unopened_packs
        ));
        Ok(format!(
            "{} · {}",
            self.config.openfut_server_host, account.persona_name
        ))
    }

    fn ensure_client_files(&mut self) -> Result<String, String> {
        let game_dir = std::path::PathBuf::from(&self.config.fifa_game_dir);
        if !crate::setup::hook_dll_deployed(&game_dir) {
            return Err("network hook is not deployed — use Setup to deploy it".into());
        }
        // The file the game reads is reconciled here, and only here: this is the
        // one moment it is guaranteed to agree with the settings on screen.
        let contents = self.config.hook_cfg_contents()?;
        crate::setup::update_hook_config(&game_dir, &contents).map_err(|e| {
            format!(
                "cannot write {} in {}: {e}",
                crate::setup::HOOK_CFG_FILE,
                self.config.fifa_game_dir
            )
        })?;
        Ok(format!(
            "hook → {}:{}",
            self.config.openfut_server_host, self.config.openfut_https_port
        ))
    }

    fn run_checks(&mut self) -> Vec<Check> {
        preflight::run(&self.config)
    }

    fn prepare_client(&mut self) -> Result<Vec<String>, String> {
        match crate::arm::arm(&self.config) {
            Ok(changes) => {
                for change in &changes {
                    self.say(format!("[launcher] prepared: {change}"));
                }
                Ok(changes)
            }
            Err(e) => Err(e.to_string()),
        }
    }

    fn ensure_service(&mut self, service: Service) -> Result<Ensured, String> {
        let spec = SpawnSpec {
            persona_id: self.config.fut_persona_id,
            persona_name: self.config.fut_persona_name.clone(),
            // Only autopatch advertises the verified resolver guard, so only it
            // receives the shared capability sink.
            capability: match service {
                Service::Autopatch => Some(CapabilityWiring {
                    server_host: self.config.openfut_server_host.clone(),
                    account_sync_port: self.config.openfut_account_sync_port,
                    sink: Arc::clone(&self.caps),
                }),
                Service::Lsx => None,
            },
        };
        self.services.lock().ensure_running(service, spec)
    }

    fn start_game(&mut self) -> Result<(), String> {
        // A new FIFA process starts with UNKNOWN capability: never inherit the
        // previous launch's. The autopatch stdout reader repopulates it.
        *self.caps.lock() = Default::default();

        let state = Arc::clone(&self.state);
        let logs = Arc::clone(&self.logs);
        let services = Arc::clone(&self.services);
        let on_exit = move || {
            // Cleanup goes through the policy rather than through habit, so the
            // list can never include a service this launcher did not start.
            let runtimes: Vec<_> = {
                let mut supervisor = services.lock();
                [Service::Lsx, Service::Autopatch]
                    .into_iter()
                    .map(|s| {
                        let runtime = supervisor.observe(s);
                        (s, runtime)
                    })
                    .collect()
            };
            for service in services_to_stop(CleanupPolicy::default(), &runtimes) {
                if let Err(e) = services.lock().stop(service) {
                    logs.lock().push(format!("[launcher] cleanup: {e}"));
                }
            }
            state.lock().phase = Phase::Idle;
            logs.lock()
                .push("[launcher] FIFA exited; launcher back to Ready.".to_string());
        };

        // Prefer the native profile; fall back to the user's shell command so an
        // existing working setup keeps working after an upgrade.
        if self.config.game_profile.configured() {
            crate::game_launch::launch(&self.config.game_profile, &self.logs, on_exit)
                .map_err(|e| e.to_string())
        } else {
            crate::setup::launch_game(
                &self.config.game_launch_command,
                &self.config.game_launch_workdir,
                Arc::clone(&self.logs),
                on_exit,
            )
            .map_err(|e| e.to_string())
        }
    }
}

/// Drives [`run_sequence`] on a worker thread. The UI thread never blocks on a
/// socket, a Polkit prompt or a process spawn.
pub struct Controller {
    pub state: Arc<Mutex<LaunchState>>,
    pub services: Arc<Mutex<ServiceSupervisor>>,
}

impl Controller {
    pub fn new(logs: Arc<Mutex<LogBuffer>>) -> Self {
        Self {
            state: Arc::new(Mutex::new(LaunchState::default())),
            services: Arc::new(Mutex::new(ServiceSupervisor::new(logs))),
        }
    }

    pub fn snapshot(&self) -> LaunchState {
        self.state.lock().clone()
    }

    fn ops(
        &self,
        config: &LauncherConfig,
        logs: &Arc<Mutex<LogBuffer>>,
        caps: &Arc<Mutex<Fifa17ClientCapabilities>>,
    ) -> RealOps {
        RealOps {
            config: config.clone(),
            services: Arc::clone(&self.services),
            logs: Arc::clone(logs),
            caps: Arc::clone(caps),
            state: Arc::clone(&self.state),
        }
    }

    /// Start the full sequence. Ignored while one is already in flight or the
    /// game is up — the button reflects that state rather than queueing work.
    pub fn launch(
        &self,
        config: &LauncherConfig,
        logs: &Arc<Mutex<LogBuffer>>,
        caps: &Arc<Mutex<Fifa17ClientCapabilities>>,
    ) {
        {
            let phase = self.state.lock().phase;
            if phase.busy() || phase == Phase::Running {
                return;
            }
        }
        let mut ops = self.ops(config, logs, caps);
        let state = Arc::clone(&self.state);
        std::thread::spawn(move || {
            run_sequence(&mut ops, &state);
        });
    }

    /// Re-observe without changing anything, for startup and after a settings
    /// change. Skipped while a launch owns the state.
    pub fn refresh(
        &self,
        config: &LauncherConfig,
        logs: &Arc<Mutex<LogBuffer>>,
        caps: &Arc<Mutex<Fifa17ClientCapabilities>>,
    ) {
        {
            let phase = self.state.lock().phase;
            if phase.busy() || phase == Phase::Running {
                return;
            }
        }
        let mut ops = self.ops(config, logs, caps);
        let state = Arc::clone(&self.state);
        std::thread::spawn(move || {
            refresh_checks(&mut ops, &state);
        });
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    /// Records what the sequence asked for, and answers however the test wants.
    #[derive(Default)]
    #[allow(clippy::type_complexity)]
    struct FakeOps {
        server_up: bool,
        client_files: Option<Result<String, String>>,
        checks: Vec<Check>,
        checks_after_prepare: Option<Vec<Check>>,
        prepare_result: Option<Result<Vec<String>, String>>,
        service_result: Vec<(Service, Result<Ensured, String>)>,
        game_result: Option<Result<(), String>>,
        // Observed calls
        prepared: usize,
        started: Vec<Service>,
        game_started: usize,
        check_runs: usize,
    }

    fn check(name: &str, state: State) -> Check {
        Check {
            name: name.into(),
            state,
            detail: String::new(),
        }
    }

    fn ready_ops() -> FakeOps {
        FakeOps {
            server_up: true,
            client_files: Some(Ok("deployed".into())),
            checks: vec![
                check("ptrace_scope (autopatch)", State::Pass),
                check("EA redirector IP is redirected", State::Pass),
                check("EA hostnames point at OpenFUT", State::Pass),
            ],
            prepare_result: Some(Ok(vec!["one".into()])),
            game_result: Some(Ok(())),
            ..FakeOps::default()
        }
    }

    impl LaunchOps for FakeOps {
        fn connect_server(&mut self) -> Result<String, String> {
            if self.server_up {
                Ok("connected".into())
            } else {
                Err("not reachable — is the OpenFUT server running?".into())
            }
        }
        fn ensure_client_files(&mut self) -> Result<String, String> {
            self.client_files
                .clone()
                .unwrap_or_else(|| Err("no client-files result configured".into()))
        }
        fn run_checks(&mut self) -> Vec<Check> {
            self.check_runs += 1;
            match (&self.checks_after_prepare, self.prepared) {
                (Some(after), n) if n > 0 => after.clone(),
                _ => self.checks.clone(),
            }
        }
        fn prepare_client(&mut self) -> Result<Vec<String>, String> {
            self.prepared += 1;
            self.prepare_result
                .clone()
                .unwrap_or_else(|| Err("no prepare configured".into()))
        }
        fn ensure_service(&mut self, service: Service) -> Result<Ensured, String> {
            self.started.push(service);
            self.service_result
                .iter()
                .find(|(s, _)| *s == service)
                .map(|(_, r)| r.clone())
                .unwrap_or(Ok(Ensured::Started))
        }
        fn start_game(&mut self) -> Result<(), String> {
            self.game_started += 1;
            self.game_result
                .clone()
                .unwrap_or_else(|| Err("no game result configured".into()))
        }
    }

    fn state() -> Arc<Mutex<LaunchState>> {
        Arc::new(Mutex::new(LaunchState::default()))
    }

    #[test]
    fn a_cold_client_is_prepared_and_started_in_dependency_order() {
        let mut ops = FakeOps {
            checks: vec![check("ptrace_scope (autopatch)", State::Fail)],
            checks_after_prepare: Some(vec![check("ptrace_scope (autopatch)", State::Pass)]),
            ..ready_ops()
        };
        let st = state();
        assert!(run_sequence(&mut ops, &st));
        assert_eq!(
            ops.prepared, 1,
            "a failing repairable check must be repaired"
        );
        // Preparation before autopatch: autopatch cannot write FIFA's memory
        // until arming has set ptrace_scope, and would silently no-op.
        assert_eq!(ops.started, vec![Service::Lsx, Service::Autopatch]);
        assert_eq!(ops.game_started, 1);
        assert_eq!(st.lock().phase, Phase::Running);
    }

    #[test]
    fn an_already_prepared_client_is_not_prepared_again() {
        let mut ops = ready_ops();
        let st = state();
        assert!(run_sequence(&mut ops, &st));
        assert_eq!(ops.prepared, 0, "no password prompt for work already done");
        let steps = &st.lock().steps;
        let prep = steps
            .iter()
            .find(|(s, _)| *s == Step::ClientPreparation)
            .expect("preparation step recorded")
            .1
            .clone();
        assert!(matches!(prep, Outcome::Skipped(_)), "{prep:?}");
    }

    #[test]
    fn healthy_services_are_reused_rather_than_restarted() {
        let mut ops = FakeOps {
            service_result: vec![
                (Service::Lsx, Ok(Ensured::Reused)),
                (Service::Autopatch, Ok(Ensured::Reused)),
            ],
            ..ready_ops()
        };
        let st = state();
        assert!(run_sequence(&mut ops, &st));
        for step in [Step::Lsx, Step::Autopatch] {
            let outcome = st
                .lock()
                .steps
                .iter()
                .find(|(s, _)| *s == step)
                .expect("service step recorded")
                .1
                .clone();
            assert!(
                matches!(outcome, Outcome::Skipped(_)),
                "{step:?} {outcome:?}"
            );
        }
        assert_eq!(ops.game_started, 1);
    }

    #[test]
    fn an_unreachable_server_stops_the_launch_before_anything_is_touched() {
        let mut ops = FakeOps {
            server_up: false,
            ..ready_ops()
        };
        let st = state();
        assert!(!run_sequence(&mut ops, &st));
        assert_eq!(ops.prepared, 0);
        assert!(ops.started.is_empty(), "nothing may be started");
        assert_eq!(ops.game_started, 0);
        assert_eq!(st.lock().phase, Phase::Failed);
        assert!(st.lock().failure.as_deref().unwrap().contains("server"));
    }

    #[test]
    fn a_service_that_fails_to_start_stops_the_launch() {
        let mut ops = FakeOps {
            service_result: vec![(Service::Autopatch, Err("autopatch: boom".into()))],
            ..ready_ops()
        };
        let st = state();
        assert!(!run_sequence(&mut ops, &st));
        assert_eq!(ops.game_started, 0, "FIFA must not start without autopatch");
        let failure = st.lock().failure.clone().unwrap();
        assert!(failure.contains("Autopatch"), "{failure}");
    }

    #[test]
    fn failed_client_preparation_stops_the_launch() {
        let mut ops = FakeOps {
            checks: vec![check("ptrace_scope (autopatch)", State::Fail)],
            prepare_result: Some(Err("pkexec: dismissed".into())),
            ..ready_ops()
        };
        let st = state();
        assert!(!run_sequence(&mut ops, &st));
        assert!(ops.started.is_empty());
        assert_eq!(ops.game_started, 0);
    }

    #[test]
    fn a_check_still_failing_after_repair_stops_the_launch() {
        // Preparation ran and claimed success, but the state it was supposed to
        // fix is still broken. Launching here is how a session dies later with
        // no message naming the cause.
        let mut ops = FakeOps {
            checks: vec![check("ptrace_scope (autopatch)", State::Fail)],
            checks_after_prepare: Some(vec![check("ptrace_scope (autopatch)", State::Fail)]),
            ..ready_ops()
        };
        let st = state();
        assert!(!run_sequence(&mut ops, &st));
        assert_eq!(ops.game_started, 0);
        let failure = st.lock().failure.clone().unwrap();
        assert!(failure.contains("still failing"), "{failure}");
    }

    #[test]
    fn client_files_failure_stops_the_launch() {
        let mut ops = FakeOps {
            client_files: Some(Err("cannot write openfut.cfg".into())),
            ..ready_ops()
        };
        let st = state();
        assert!(!run_sequence(&mut ops, &st));
        assert_eq!(ops.game_started, 0);
        assert!(ops.started.is_empty());
    }

    #[test]
    fn cleanup_never_stops_a_service_the_launcher_did_not_start() {
        let foreign = ServiceRuntime {
            running: true,
            started_by_launcher: false,
            pid: Some(4242),
            detail: None,
        };
        let ours = ServiceRuntime {
            running: true,
            started_by_launcher: true,
            pid: Some(99),
            detail: None,
        };
        let runtimes = [(Service::Lsx, foreign), (Service::Autopatch, ours)];

        // Even under the most aggressive policy, a foreign service is untouched.
        let aggressive = CleanupPolicy {
            stop_launcher_started_services: true,
        };
        assert_eq!(
            services_to_stop(aggressive, &runtimes),
            vec![Service::Autopatch]
        );

        // And the shipped policy keeps both alive for the next launch.
        assert!(services_to_stop(CleanupPolicy::default(), &runtimes).is_empty());
    }

    #[test]
    fn readiness_is_never_green_while_a_dependency_is_not() {
        assert_eq!(
            overall(
                Phase::Idle,
                Readiness::Ready,
                Readiness::Ready,
                Readiness::Attention,
                Readiness::Ready
            ),
            Readiness::Attention
        );
        // Never checked is not the same as checked and fine.
        assert_eq!(
            overall(
                Phase::Idle,
                Readiness::Ready,
                Readiness::Unknown,
                Readiness::Ready,
                Readiness::Ready
            ),
            Readiness::Unknown
        );
        assert_eq!(
            overall(
                Phase::Idle,
                Readiness::Ready,
                Readiness::Ready,
                Readiness::Ready,
                Readiness::Ready
            ),
            Readiness::Ready
        );
        // A running game reports Ready even though a launch is not in flight.
        assert_eq!(
            overall(
                Phase::Running,
                Readiness::Unknown,
                Readiness::Unknown,
                Readiness::Unknown,
                Readiness::Unknown
            ),
            Readiness::Ready
        );
    }

    #[test]
    fn client_integration_is_unknown_until_checks_have_run() {
        let mut st = LaunchState::default();
        assert_eq!(client_integration(&st), Readiness::Unknown);

        st.checks = Some(vec![check("ptrace_scope (autopatch)", State::Fail)]);
        assert_eq!(client_integration(&st), Readiness::Attention);

        st.checks = Some(vec![check("ptrace_scope (autopatch)", State::Pass)]);
        assert_eq!(client_integration(&st), Readiness::Ready);

        // Only skipped checks means nothing was actually verified.
        st.checks = Some(vec![check("ptrace_scope (autopatch)", State::Skipped)]);
        assert_eq!(client_integration(&st), Readiness::Unknown);
    }
}