nornir 0.4.18

//! 📡 Live release run pane.
//!
//! **Durable source = the warehouse `release_events` table** (LAW
//! "persist-to-warehouse-stream-not-tmp"). On load/reload the pane *hydrates*
//! from `release_events` — the same table the 🚀 Release tab and the
//! `nornir release events` CLI read — so a run **survives a reboot** and is
//! **visible to other clients** the moment it lands in the warehouse, exactly
//! like every other release surface.
//!
//! On top of that durable baseline, a **fast live-tail** keeps the pane moving
//! at sub-second latency while a run is in flight:
//!   * **local** mode tails `<workspace>/.nornir/logs/release-run-*.events.ndjson`
//!     (the producer flushes there per line — cheaper than a warehouse append per
//!     event), and
//!   * **remote** (thin-client) mode streams the run from a `nornir-server` over
//!     `Release.Progress`.
//!
//! The tail is a *fallback accelerator*, never the source of truth: if the
//! `/tmp` log is gone (reboot, GC) the warehouse-hydrated events still render,
//! and a reload re-reads the warehouse. eframe's `App::update` runs sync at
//! ~60 Hz so no tokio/SSE client is needed for the local pane.

use std::fs::File;
use std::io::{BufRead, BufReader, Seek, SeekFrom};
use std::path::{Path, PathBuf};
use std::sync::{Arc, Mutex};
use std::thread;
use std::time::Duration;

use eframe::egui::{self, RichText, ScrollArea};
use serde::Deserialize;

use super::facett_theme::{Theme, GREEN, RED};

use crate::warehouse::iceberg::IcebergWarehouse;
use crate::warehouse::release_events::{
    self, query_release_events, EventSelector, ReleaseEventRow,
};

#[derive(Debug, Clone, Deserialize)]
#[serde(tag = "kind")]
pub enum LiveEvent {
    #[serde(rename = "run_start")]
    RunStart { run_id: String, workspace: String },
    #[serde(rename = "repo_start")]
    RepoStart { repo: String, sha: String },
    #[serde(rename = "phase_start")]
    PhaseStart { repo: String, phase: String },
    #[serde(rename = "phase_end")]
    PhaseEnd { repo: String, phase: String, ok: bool, duration_ms: u64 },
    #[serde(rename = "binary_start")]
    BinaryStart { repo: String, binary: String },
    #[serde(rename = "test_pass")]
    TestPass { repo: String, binary: String, name: String },
    #[serde(rename = "test_fail")]
    TestFail { repo: String, binary: String, name: String },
    #[serde(rename = "binary_done")]
    BinaryDone { repo: String, binary: String, passed: u32, failed: u32 },
    #[serde(rename = "repo_end")]
    RepoEnd { repo: String, ok: bool },
    #[serde(rename = "run_end")]
    RunEnd { run_id: String, ok: bool },
}

/// Where the durable hydrate reads `release_events` from (mirrors the other
/// tabs' local/remote split). The fast live-tail (`/tmp` file or `Release.Progress`
/// stream) layers on top of whichever durable baseline this provides.
#[derive(Clone)]
enum Durable {
    /// Local warehouse root — hydrate by opening it read-only and querying
    /// `release_events` for the newest run.
    Local(PathBuf),
    /// Remote server — hydrate the durable baseline over `Viz.ReleaseEvents`
    /// (the warehouse lives on the server, which holds the redb lock), then the
    /// `Release.Progress` stream layers the live tail on top. Carries
    /// `(endpoint, token, workspace)`: the workspace scopes the RPC, the endpoint
    /// is also the `state_json` label.
    Remote { endpoint: String, token: String, workspace: String },
    /// No durable source (e.g. a test that injects events directly).
    None,
}

#[derive(Default)]
struct Shared {
    events: Vec<LiveEvent>,
    err: Option<String>,
    file_path: Option<PathBuf>,
    eof_run_ended: bool,
    /// True once the warehouse hydrate (the durable read) has populated the
    /// baseline — so `state_json` / the pane can show the run survived a reboot
    /// even before any `/tmp` tail line arrives.
    hydrated_from_warehouse: bool,
    /// `run_id` of the run the durable hydrate loaded (the newest in the table).
    hydrated_run_id: Option<String>,
}

pub struct LiveRunState {
    log_dir: PathBuf,
    /// When set (thin-client / remote viz), stream the run from a `nornir-server`
    /// over `Release.Progress` instead of tailing a local file. `(endpoint, token)`.
    remote: Option<(String, String)>,
    /// The durable source the pane hydrates from on load/reload (the warehouse).
    durable: Durable,
    shared: Arc<Mutex<Shared>>,
    started: bool,
    theme: Theme,
}

impl LiveRunState {
    /// `log_dir` is `<workspace_root>/.nornir/logs`; `warehouse_root` is the
    /// warehouse the durable `release_events` hydrate reads from. Construction
    /// does not hydrate or start the tail — that happens on first `draw()` so a
    /// user who never opens the tab pays nothing.
    pub fn new(log_dir: PathBuf, warehouse_root: PathBuf) -> Self {
        Self {
            log_dir,
            remote: None,
            durable: Durable::Local(warehouse_root),
            shared: Arc::new(Mutex::new(Shared::default())),
            started: false,
            theme: Theme::default(),
        }
    }

    /// Set the facett palette the pane paints with.
    pub fn set_palette(&mut self, t: Theme) {
        self.theme = t;
    }

    /// Remote constructor: stream the live run from a running `nornir-server`
    /// over the `Release.Progress` gRPC (e.g. a friend's viz watching your
    /// server over Tailscale). The server's warehouse is the durable source; the
    /// stream is both its hydrate and its live tail.
    pub fn new_remote(endpoint: String, token: String, workspace: String) -> Self {
        Self {
            log_dir: PathBuf::new(),
            remote: Some((endpoint.clone(), token.clone())),
            durable: Durable::Remote { endpoint, token, workspace },
            shared: Arc::new(Mutex::new(Shared::default())),
            started: false,
            theme: Theme::default(),
        }
    }

    /// Re-point the thin-mode durable hydrate at a new workspace (the picker
    /// switched). No-op when local; the caller follows with `reload()`.
    pub fn set_workspace(&mut self, workspace: String) {
        if let Durable::Remote { workspace: w, .. } = &mut self.durable {
            *w = workspace;
        }
    }

    /// Test-only: inject release-op rows as the durable hydrate (no warehouse on
    /// disk), exactly as if `release_events` had been read. Mirrors the Release
    /// tab's `inject_for_test` so the inject-and-assert harness can read the
    /// hydrated run back out of `state_json`.
    #[doc(hidden)]
    pub fn inject_for_test(&mut self, rows: Vec<ReleaseEventRow>) {
        self.durable = Durable::None;
        self.started = true; // don't spawn a tail thread in the headless test
        let (events, run_id) = events_from_release_rows(rows);
        let mut s = self.shared.lock().unwrap();
        s.events = events;
        s.hydrated_from_warehouse = true;
        s.hydrated_run_id = run_id;
        s.err = None;
    }

    /// Re-scope (workspace switch / reload): re-read the durable warehouse source
    /// so the pane re-hydrates from `release_events`. The live tail keeps running.
    pub fn reload(&mut self) {
        {
            let mut s = self.shared.lock().unwrap_or_else(|p| p.into_inner());
            s.hydrated_from_warehouse = false;
            s.hydrated_run_id = None;
        }
        self.hydrate_from_warehouse();
    }

    /// Durable read: open the warehouse read-only and load the **newest run**'s
    /// `release_events` rows as the baseline the pane renders. Lock-tolerant +
    /// read-only so it coexists with a live server holding the catalog lock, the
    /// same read path `nornir release events` / the Release tab use. Best-effort:
    /// a read error is recorded into `err` and does not panic the UI.
    fn hydrate_from_warehouse(&mut self) {
        // Read the durable `release_events` baseline: locally by opening the
        // warehouse, remotely over Viz.ReleaseEvents (the server holds the lock).
        // The Release.Progress stream then layers the live tail on top — but with
        // no run in flight (a historical workspace) the stream is silent, so this
        // durable read is what makes the pane non-empty in thin mode.
        let res = match &self.durable {
            Durable::Local(root) => {
                super::trace::emit_in(
                    "live.hydrate",
                    &serde_json::json!({ "source": "warehouse.release_events", "root": root.display().to_string() }),
                );
                IcebergWarehouse::open_read_only(root)
                    .and_then(|wh| wh.block_on(query_release_events(&wh, &EventSelector::All)))
            }
            Durable::Remote { endpoint, token, workspace } => {
                super::trace::emit_in(
                    "live.hydrate",
                    &serde_json::json!({ "source": "Viz.ReleaseEvents", "endpoint": endpoint, "workspace": workspace }),
                );
                super::remote::fetch_release_events(endpoint, token, workspace)
            }
            Durable::None => return,
        };
        let mut s = self.shared.lock().unwrap_or_else(|p| p.into_inner());
        match res {
            Ok(rows) => {
                let (events, run_id) = events_from_release_rows(rows);
                let n = events.len();
                s.events = events;
                s.hydrated_from_warehouse = true;
                s.hydrated_run_id = run_id.clone();
                s.err = None;
                super::trace::emit_out(
                    "live.hydrate",
                    &serde_json::json!({ "run_id": run_id, "events": n }),
                );
            }
            Err(e) => {
                // No table yet / empty warehouse is normal before the first run —
                // record it but keep whatever the live tail may have collected.
                s.err = Some(format!("{e:#}"));
                super::trace::emit_out(
                    "live.hydrate",
                    &serde_json::json!({ "error": format!("{e:#}") }),
                );
            }
        }
    }

    fn ensure_started(&mut self) {
        if self.started {
            return;
        }
        self.started = true;
        // Durable FIRST: hydrate the baseline from the warehouse so the run is
        // visible on load even if no `/tmp` log exists (e.g. after a reboot).
        self.hydrate_from_warehouse();
        let shared = Arc::clone(&self.shared);
        if let Some((endpoint, token)) = self.remote.clone() {
            thread::Builder::new()
                .name("nornir-live-remote".into())
                .spawn(move || remote_loop(endpoint, token, shared))
                .expect("spawn live remote thread");
        } else {
            let log_dir = self.log_dir.clone();
            thread::Builder::new()
                .name("nornir-live-tail".into())
                .spawn(move || tail_loop(log_dir, shared))
                .expect("spawn tail thread");
        }
    }

    pub fn draw(&mut self, ui: &mut egui::Ui) {
        self.ensure_started();
        let theme = self.theme;
        let remote_ep = self.remote.as_ref().map(|(e, _)| e.clone());
        // Recover a poisoned lock instead of cascade-panicking the UI thread: if
        // a background stream/tail thread panicked mid-write the shared buffer is
        // still readable, so degrade to whatever it last held rather than crash.
        let shared = self.shared.lock().unwrap_or_else(|p| p.into_inner());

        if let Some(err) = &shared.err {
            ui.colored_label(RED, err);
        }
        ui.horizontal(|ui| {
            ui.label("durable:");
            match &self.durable {
                Durable::Local(p) => ui.monospace(format!("warehouse {}", p.display())),
                Durable::Remote { endpoint, workspace, .. } => {
                    ui.monospace(format!("server {endpoint} ws={workspace} (Viz.ReleaseEvents)"))
                }
                Durable::None => ui.monospace("(injected)"),
            };
            if shared.hydrated_from_warehouse {
                ui.colored_label(GREEN, "✓ hydrated");
            } else {
                ui.weak("(loading…)");
            }
        });
        ui.horizontal(|ui| {
            if let Some(ep) = &remote_ep {
                ui.label("live-tail:");
                ui.monospace(format!("server {ep}"));
            } else {
                ui.label("live-tail:");
                if let Some(p) = &shared.file_path {
                    ui.monospace(p.display().to_string());
                } else {
                    ui.weak("(warehouse baseline; waiting for next release-run-*.events.ndjson)");
                }
            }
        });
        ui.separator();

        let summary = RunSummary::from_events(&shared.events);

        ui.horizontal(|ui| {
            ui.label(RichText::new("run").strong());
            ui.monospace(&summary.run_id);
            ui.separator();
            ui.label("workspace:");
            ui.monospace(&summary.workspace);
            ui.separator();
            match summary.run_ok {
                None => ui.colored_label(theme.accent, "● running"),
                Some(true) => ui.colored_label(GREEN, "✓ done"),
                Some(false) => ui.colored_label(RED, "✗ failed"),
            };
        });
        ui.horizontal(|ui| {
            ui.label(RichText::new("repo").strong());
            ui.monospace(&summary.current_repo);
            ui.separator();
            ui.label("phase:");
            ui.monospace(&summary.current_phase);
            ui.separator();
            ui.label("binary:");
            ui.monospace(short_bin(&summary.current_binary));
        });
        ui.horizontal(|ui| {
            ui.colored_label(GREEN, format!("✓ {}", summary.total_pass));
            ui.colored_label(RED, format!("✗ {}", summary.total_fail));
        });
        ui.separator();

        // Scrolling log: most recent at top, last 500 lines.
        ScrollArea::vertical().auto_shrink([false, false]).stick_to_bottom(true).show(ui, |ui| {
            for ev in shared.events.iter().rev().take(500).rev() {
                render_event_row(ui, ev, &theme);
            }
        });

        // Drive the next frame so live updates appear without user input.
        ui.ctx().request_repaint_after(Duration::from_millis(200));
    }

    /// Test/introspection hook (LAW #6): the live run the pane is rendering —
    /// the durable source, whether the warehouse hydrate landed, the run header,
    /// and the rendered event lines — folded into the app's `state_json`. This is
    /// the proof the pane reads from the warehouse, not just `/tmp`.
    pub fn state_json(&self) -> serde_json::Value {
        let shared = self.shared.lock().unwrap_or_else(|p| p.into_inner());
        let summary = RunSummary::from_events(&shared.events);
        let lines: Vec<String> = shared.events.iter().map(event_line).collect();
        serde_json::json!({
            "durable_source": match &self.durable {
                Durable::Local(p) => format!("warehouse {}", p.display()),
                Durable::Remote { endpoint, workspace, .. } => {
                    format!("server {endpoint} ws={workspace} (Viz.ReleaseEvents)")
                }
                Durable::None => "injected".to_string(),
            },
            "hydrated_from_warehouse": shared.hydrated_from_warehouse,
            "hydrated_run_id": shared.hydrated_run_id,
            "live_tail": match &self.remote {
                Some((e, _)) => format!("server {e} (Release.Progress)"),
                None => shared.file_path.as_ref()
                    .map(|p| format!("file {}", p.display()))
                    .unwrap_or_else(|| "(none yet)".to_string()),
            },
            "error": shared.err,
            "run_id": summary.run_id,
            "workspace": summary.workspace,
            "run_ok": summary.run_ok,
            "current_repo": summary.current_repo,
            "current_phase": summary.current_phase,
            "total_pass": summary.total_pass,
            "total_fail": summary.total_fail,
            "events": shared.events.len(),
            "lines": lines,
            "palette": self.theme.name,
        })
    }
}

/// Convert durable `release_events` rows (newest run only) into the `LiveEvent`
/// stream the pane renders, so the warehouse table and the `/tmp`/SSE live tail
/// feed one identical render path. Returns the events + the hydrated `run_id`.
///
/// Mapping (the durable `op × phase × status` boundary → live event):
///   * `op == "run"`, `phase == start`  → `RunStart`   (carries `run_id`)
///   * `op == "run"`, `phase == end`    → `RunEnd`     (`ok = status == ok`)
///   * any op, `phase == start`         → `PhaseStart` (the `[repo] op` boundary)
///   * any op, `phase == end`           → `PhaseEnd`   (`ok` + `duration_ms`)
fn events_from_release_rows(rows: Vec<ReleaseEventRow>) -> (Vec<LiveEvent>, Option<String>) {
    use release_events::{phase, status};
    // Pick the newest run (max ts), so the pane shows the live/most-recent run —
    // the same "newest run on top" rule the Release tab uses.
    let mut latest: Option<(&str, i64)> = None;
    for r in &rows {
        let cand = (r.run_id.as_str(), r.ts_micros);
        if latest.map_or(true, |(_, ts)| cand.1 >= ts) {
            latest = Some(cand);
        }
    }
    let Some((run_id, _)) = latest else {
        return (Vec::new(), None);
    };
    let run_id = run_id.to_string();
    let mut run_rows: Vec<&ReleaseEventRow> =
        rows.iter().filter(|r| r.run_id == run_id).collect();
    run_rows.sort_by_key(|r| r.seq);

    let mut out: Vec<LiveEvent> = Vec::with_capacity(run_rows.len());
    for r in run_rows {
        let ev = match (r.op.as_str(), r.phase.as_str()) {
            ("run", p) if p == phase::START => LiveEvent::RunStart {
                run_id: r.run_id.clone(),
                // `run/start` detail carries the workspace label when present.
                workspace: if r.detail.is_empty() { r.run_id.clone() } else { r.detail.clone() },
            },
            ("run", p) if p == phase::END => LiveEvent::RunEnd {
                run_id: r.run_id.clone(),
                ok: r.status == status::OK,
            },
            (_, p) if p == phase::START => LiveEvent::PhaseStart {
                repo: r.component.clone(),
                phase: r.op.clone(),
            },
            (_, p) if p == phase::END => LiveEvent::PhaseEnd {
                repo: r.component.clone(),
                phase: r.op.clone(),
                ok: r.status == status::OK,
                duration_ms: r.elapsed_ms.unwrap_or(0).max(0) as u64,
            },
            _ => continue, // skip phases (skip/etc) the pane doesn't render
        };
        out.push(ev);
    }
    (out, Some(run_id))
}

/// The reduced run header the pane shows + `state_json` exposes.
struct RunSummary {
    run_id: String,
    workspace: String,
    current_repo: String,
    current_phase: String,
    current_binary: String,
    total_pass: u32,
    total_fail: u32,
    run_ok: Option<bool>,
}

impl RunSummary {
    fn from_events(events: &[LiveEvent]) -> Self {
        let mut s = RunSummary {
            run_id: "—".into(),
            workspace: "—".into(),
            current_repo: "—".into(),
            current_phase: "—".into(),
            current_binary: "—".into(),
            total_pass: 0,
            total_fail: 0,
            run_ok: None,
        };
        for ev in events {
            match ev {
                LiveEvent::RunStart { run_id, workspace } => {
                    s.run_id = run_id.clone();
                    s.workspace = workspace.clone();
                    s.run_ok = None;
                    s.total_pass = 0;
                    s.total_fail = 0;
                }
                LiveEvent::RepoStart { repo, .. } => s.current_repo = repo.clone(),
                LiveEvent::PhaseStart { repo, phase } => {
                    s.current_repo = repo.clone();
                    s.current_phase = phase.clone();
                }
                LiveEvent::PhaseEnd { repo, phase, .. } => {
                    s.current_repo = repo.clone();
                    s.current_phase = phase.clone();
                }
                LiveEvent::BinaryStart { binary, .. } => s.current_binary = binary.clone(),
                LiveEvent::BinaryDone { passed, failed, .. } => {
                    s.total_pass += passed;
                    s.total_fail += failed;
                }
                LiveEvent::TestPass { .. } => s.total_pass += 1,
                LiveEvent::TestFail { .. } => s.total_fail += 1,
                LiveEvent::RunEnd { ok, .. } => s.run_ok = Some(*ok),
                _ => {}
            }
        }
        s
    }
}

/// One stable text line per event — what the pane's log row renders, exposed in
/// `state_json["lines"]` so the headless matrix asserts the rendered content.
fn event_line(ev: &LiveEvent) -> String {
    match ev {
        LiveEvent::RunStart { run_id, workspace } => format!("▶ run {run_id} ({workspace})"),
        LiveEvent::RepoStart { repo, sha } => format!("▶ {repo}  sha={}", short_sha(sha)),
        LiveEvent::PhaseStart { repo, phase } => format!("… {repo} {phase} start"),
        LiveEvent::PhaseEnd { repo, phase, ok, duration_ms } => format!(
            "{} {repo} {phase} ({:.1}s)",
            if *ok { "✓" } else { "✗" },
            *duration_ms as f32 / 1000.0,
        ),
        LiveEvent::BinaryStart { repo, binary } => format!("📂 {repo}  {}", short_bin(binary)),
        LiveEvent::TestPass { name, .. } => format!("✓ {name}"),
        LiveEvent::TestFail { name, .. } => format!("✗ {name}"),
        LiveEvent::BinaryDone { passed, failed, .. } => format!("≡ {passed} passed, {failed} failed"),
        LiveEvent::RepoEnd { repo, ok } => {
            format!("{} {repo} done", if *ok { "✓" } else { "✗" })
        }
        LiveEvent::RunEnd { ok, .. } => {
            (if *ok { "✓ run complete" } else { "✗ run failed" }).to_string()
        }
    }
}

fn render_event_row(ui: &mut egui::Ui, ev: &LiveEvent, theme: &Theme) {
    match ev {
        LiveEvent::BinaryStart { repo, binary } => {
            ui.horizontal(|ui| {
                ui.colored_label(theme.accent, "📂");
                ui.monospace(format!("{repo}  {}", short_bin(binary)));
            });
        }
        LiveEvent::PhaseStart { repo, phase } => {
            ui.horizontal(|ui| {
                ui.colored_label(theme.accent, "…");
                ui.monospace(format!("{repo}  {phase} start"));
            });
        }
        LiveEvent::TestPass { name, .. } => {
            ui.horizontal(|ui| {
                ui.colored_label(GREEN, "✓");
                ui.label(name);
            });
        }
        LiveEvent::TestFail { name, .. } => {
            ui.horizontal(|ui| {
                ui.colored_label(RED, "✗");
                ui.colored_label(RED, name);
            });
        }
        LiveEvent::BinaryDone { passed, failed, .. } => {
            ui.horizontal(|ui| {
                ui.colored_label(theme.text_dim, "≡");
                ui.label(format!("{passed} passed, {failed} failed"));
            });
        }
        LiveEvent::PhaseEnd { repo, phase, ok, duration_ms } => {
            let col = if *ok { GREEN } else { RED };
            ui.colored_label(col, format!(
                "{} {repo} {phase} ({:.1}s)",
                if *ok { "✓" } else { "✗" },
                *duration_ms as f32 / 1000.0,
            ));
        }
        LiveEvent::RepoStart { repo, sha } => {
            ui.colored_label(theme.text, format!("▶ {repo}  sha={}", short_sha(sha)));
        }
        LiveEvent::RunStart { run_id, workspace } => {
            ui.colored_label(theme.text, format!("▶ run {run_id} ({workspace})"));
        }
        LiveEvent::RunEnd { ok, .. } => {
            let col = if *ok { GREEN } else { RED };
            ui.colored_label(col, if *ok { "✓ run complete" } else { "✗ run failed" });
        }
        _ => {}
    }
}

fn short_bin(s: &str) -> String {
    // cargo prints `Running tests/foo.rs (target/debug/deps/foo-abcd)`
    // — keep the unittests / tests/<name> half, drop the deps path.
    s.split_whitespace().next().unwrap_or(s).to_string()
}

fn short_sha(s: &str) -> String {
    // Char-boundary safe: SHAs are ASCII, but a malformed/placeholder ref could
    // carry multibyte UTF-8 and `&s[..12]` would panic mid-codepoint.
    if s.chars().count() > 12 { s.chars().take(12).collect() } else { s.to_string() }
}

/// Remote counterpart to [`tail_loop`]: stream the live run from a
/// `nornir-server` over `Release.Progress`. Each event is pushed into the same
/// `Shared` state the pane renders. The server closes the stream after `RunEnd`;
/// we then reconnect (after a short backoff) so the pane keeps watching for the
/// next release run — agents hammering components show up live as they happen.
fn remote_loop(endpoint: String, token: String, shared: Arc<Mutex<Shared>>) {
    loop {
        {
            let mut s = shared.lock().unwrap();
            s.events.clear();
            s.err = None;
            s.eof_run_ended = false;
            s.file_path = None;
        }
        let sink = Arc::clone(&shared);
        let res = super::remote::stream_progress(&endpoint, &token, move |ev| {
            let mut s = sink.lock().unwrap();
            if let LiveEvent::RunEnd { .. } = &ev {
                s.eof_run_ended = true;
            }
            s.events.push(ev);
        });
        if let Err(e) = res {
            shared.lock().unwrap().err = Some(format!("stream from {endpoint}: {e:#}"));
        }
        // Stream ended (RunEnd) or errored — wait, then reconnect for the next run.
        thread::sleep(Duration::from_secs(2));
    }
}

fn tail_loop(log_dir: PathBuf, shared: Arc<Mutex<Shared>>) {
    let mut current: Option<(PathBuf, BufReader<File>)> = None;
    loop {
        // Re-scan for the newest events file every cycle so a fresh
        // run (new timestamp suffix) supersedes the previous one.
        if let Some(newest) = newest_events_file(&log_dir) {
            let pick = match &current {
                Some((p, _)) if *p == newest => None,
                _ => Some(newest),
            };
            if let Some(path) = pick {
                match File::open(&path) {
                    Ok(mut f) => {
                        let _ = f.seek(SeekFrom::Start(0));
                        let mut s = shared.lock().unwrap();
                        // A live `/tmp` run supersedes the warehouse baseline: it
                        // is the same run at sub-second latency. (The warehouse
                        // hydrate already proved the run is durable; the tail just
                        // makes it move faster.)
                        s.events.clear();
                        s.err = None;
                        s.eof_run_ended = false;
                        s.file_path = Some(path.clone());
                        drop(s);
                        current = Some((path, BufReader::new(f)));
                    }
                    Err(e) => {
                        shared.lock().unwrap().err = Some(format!("open failed: {e}"));
                    }
                }
            }
        }

        if let Some((_, reader)) = current.as_mut() {
            let mut line = String::new();
            loop {
                line.clear();
                match reader.read_line(&mut line) {
                    Ok(0) => break, // EOF — wait, then retry / re-scan
                    Ok(_) => {
                        let trimmed = line.trim_end_matches(['\r', '\n']);
                        if trimmed.is_empty() { continue; }
                        match serde_json::from_str::<LiveEvent>(trimmed) {
                            Ok(ev) => {
                                let mut s = shared.lock().unwrap();
                                if let LiveEvent::RunEnd { .. } = &ev {
                                    s.eof_run_ended = true;
                                }
                                s.events.push(ev);
                            }
                            Err(_) => {
                                // Forward-compat: ignore unknown variants.
                            }
                        }
                    }
                    Err(e) => {
                        shared.lock().unwrap().err = Some(format!("read failed: {e}"));
                        break;
                    }
                }
            }
        }

        thread::sleep(Duration::from_millis(250));
    }
}

fn newest_events_file(log_dir: &Path) -> Option<PathBuf> {
    let rd = std::fs::read_dir(log_dir).ok()?;
    let mut best: Option<(std::time::SystemTime, PathBuf)> = None;
    for entry in rd.flatten() {
        let p = entry.path();
        let ok_name = p
            .file_name()
            .and_then(|s| s.to_str())
            .map(|s| s.starts_with("release-run-") && s.ends_with(".events.ndjson"))
            .unwrap_or(false);
        if !ok_name { continue; }
        if let Ok(m) = entry.metadata() {
            if let Ok(t) = m.modified() {
                if best.as_ref().map_or(true, |(bt, _)| t > *bt) {
                    best = Some((t, p));
                }
            }
        }
    }
    best.map(|(_, p)| p)
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::warehouse::release_events::{phase, status};

    fn row(
        run: &str,
        seq: i64,
        comp: &str,
        op: &str,
        ph: &str,
        st: &str,
        ms: Option<i64>,
        detail: &str,
    ) -> ReleaseEventRow {
        ReleaseEventRow {
            run_id: run.into(),
            seq,
            ts_micros: seq * 1_000,
            component: comp.into(),
            repo: comp.into(),
            op: op.into(),
            phase: ph.into(),
            status: st.into(),
            detail: detail.into(),
            depends_on: None,
            elapsed_ms: ms,
        }
    }

    #[test]
    fn release_rows_become_live_events_for_newest_run() {
        // Two runs; the newest (higher ts) must be the one hydrated.
        let rows = vec![
            row("old", 0, "old", "run", phase::START, status::RUNNING, None, "wsA"),
            row("run-1", 0, "run-1", "run", phase::START, status::RUNNING, None, "holger"),
            row("run-1", 2, "znippy", "test", phase::END, status::OK, Some(1200), "3 passed"),
            row("run-1", 1, "znippy", "test", phase::START, status::RUNNING, None, ""),
            row("run-1", 3, "run-1", "run", phase::END, status::OK, None, ""),
        ];
        let (events, run_id) = events_from_release_rows(rows);
        assert_eq!(run_id.as_deref(), Some("run-1"), "newest run hydrated");

        // The run header reduces from the events: run id, workspace, ok.
        let s = RunSummary::from_events(&events);
        assert_eq!(s.run_id, "run-1");
        assert_eq!(s.workspace, "holger", "run/start detail → workspace label");
        assert_eq!(s.run_ok, Some(true), "run/end ok → done");
        assert_eq!(s.current_repo, "znippy");

        // The rendered lines carry the real op boundaries (durable → live).
        let lines: Vec<String> = events.iter().map(event_line).collect();
        assert!(lines.iter().any(|l| l == "… znippy test start"), "got {lines:?}");
        assert!(lines.iter().any(|l| l == "✓ znippy test (1.2s)"), "got {lines:?}");
        assert!(lines.iter().any(|l| l == "✓ run complete"), "got {lines:?}");
    }

    #[test]
    fn inject_hydrates_state_json_without_warehouse() {
        let mut live = LiveRunState::new(PathBuf::new(), PathBuf::new());
        live.inject_for_test(vec![
            row("r", 0, "r", "run", phase::START, status::RUNNING, None, "ws"),
            row("r", 1, "znippy", "test", phase::END, status::OK, Some(500), ""),
        ]);
        let v = live.state_json();
        assert_eq!(v["hydrated_from_warehouse"], true);
        assert_eq!(v["hydrated_run_id"], "r");
        assert_eq!(v["run_id"], "r");
        assert_eq!(v["workspace"], "ws");
        let lines: Vec<&str> = v["lines"].as_array().unwrap().iter().filter_map(|l| l.as_str()).collect();
        assert!(lines.iter().any(|l| *l == "✓ znippy test (0.5s)"), "got {lines:?}");
    }
}