nornir 0.4.22

//! Knowledge-map tab: **background** scan + bubble chart of repos.
//!
//! On first entry (and on "↻ rescan" / a workspace switch) the tab kicks off one
//! [`crate::knowledge::scan_all`] per configured repo, in parallel via rayon, on
//! a **dedicated background thread** — the UI thread NEVER blocks on the scan.
//! While the thread runs the tab paints "⏳ scanning …" and requests a repaint;
//! when the slot fills, the results swap in. Results are cached until the next
//! rescan / workspace change.
//!
//! Root cause of the historical ~5s click stall: the rayon scan (syn parse of
//! every `.rs` + a `gix` HEAD-history walk per repo) ran **synchronously on the
//! UI thread** inside `draw()`, so the first frame after the tab was selected
//! froze for the whole wall-time of the slowest repo scan. Moving the scan to a
//! `std::thread::spawn` (the LiveRun / Security tab pattern) keeps the UI live.
//!
//! Visual model:
//!   - one bubble per crate, x = symbol-count, y = call-count (both log)
//!   - bubble radius = file count of the crate
//!   - bubble color = git heat (max commits-30d across the crate's files)
//!   - hovering shows breakdown (kinds, top-N functions by call-out)

use std::collections::BTreeMap;
use std::path::{Path, PathBuf};
use std::sync::{Arc, Mutex};
use std::time::Instant;

use eframe::egui::{self, Color32, Pos2, Sense, Stroke, Vec2};
use serde::{Deserialize, Serialize};

use crate::knowledge::{self, ScanResult};
use crate::viz::trace;

use super::facett_theme::Theme;

/// The handoff slot a background scan thread fills exactly once. `None` until the
/// thread finishes; then the finished per-repo scans (input order preserved).
type ScanSlot = Arc<Mutex<Option<Vec<(String, Result<ScanResult, String>)>>>>;

/// Remote source for thin mode: the server runs the scan (it owns the cloned
/// repos) and ships back a [`KnowledgeSummary`] over `Viz.Knowledge`.
#[derive(Clone)]
struct RemoteSrc {
    endpoint: String,
    token: String,
    workspace: String,
}

/// The handoff slot a remote background fetch fills once — `Ok(summary)` or a
/// human error string. Mirrors [`ScanSlot`] for the RPC path.
type RemoteSlot = Arc<Mutex<Option<Result<KnowledgeSummary, String>>>>;

/// INPUT of a Knowledge rescan — the workspace_root and the repo list the scan
/// was handed (the case-sensitive `workspace_root.join(repo)` happens per repo).
#[derive(Serialize)]
struct ScanIn {
    workspace_root: String,
    repos: Vec<String>,
}

/// OUTPUT data for one scanned repo — resolved path, whether it exists on disk
/// (a case mismatch like `njord` vs `Njord` shows up as `exists:false`), the
/// per-kind counts, timing, and the error if the scan failed.
#[derive(Serialize)]
struct RepoScan {
    repo: String,
    path: String,
    exists: bool,
    symbols: usize,
    calls: usize,
    features: usize,
    git_files: usize,
    ms: u64,
    error: Option<String>,
}

/// OUTPUT summary of a rescan across all repos.
#[derive(Serialize)]
struct ScanOut {
    repos_ok: usize,
    repos_total: usize,
    ms: u64,
}

/// The rendered table payload — the exact per-crate rows the user sees.
#[derive(Serialize)]
struct RenderOut<'a> {
    crates: usize,
    bubbles: &'a [Bubble],
}

pub struct KnowledgeState {
    workspace_root: PathBuf,
    repos: Vec<String>,
    /// `Some` ⇒ thin mode: scan runs server-side via `Viz.Knowledge`; the local
    /// `workspace_root.join(repo)` scan is skipped (there's no checkout here).
    remote: Option<RemoteSrc>,
    scans: Vec<(String, Result<ScanResult, String>)>,
    /// Remote-mode rendered summary (decoded from the RPC) — `None` until the
    /// first fetch completes. The local path uses `scans`; the remote path uses
    /// this (it has no `ScanResult`s, only the server's rollup).
    remote_summary: Option<KnowledgeSummary>,
    /// In-flight remote fetch slot + its start time (the "fetching Ns" label).
    remote_pending: Option<(RemoteSlot, Instant)>,
    /// Last remote error (surfaced in the panel + `state_json`).
    remote_error: Option<String>,
    last_scan: Option<Instant>,
    /// Set when a rescan should be kicked off on the next `draw()` — flipped on
    /// construction, by the "↻ rescan" button, and by a workspace switch.
    rescan_requested: bool,
    /// The in-flight background scan's handoff slot, plus when it started (for
    /// the "scanning Ns" label). `Some` while a scan thread is running; the slot
    /// is drained into `scans` the first frame the thread has finished.
    pending: Option<(ScanSlot, Instant)>,
    /// Set when a rescan produces fresh `scans`; gates the `knowledge.render`
    /// trace event so it fires once per data change, not once per frame (the
    /// tab redraws at ~60fps — emitting render every frame would flood the
    /// trace). Cleared after the render event is emitted.
    render_dirty: bool,
    theme: Theme,
}

impl KnowledgeState {
    pub fn new(workspace_root: PathBuf, repos: Vec<String>) -> Self {
        Self {
            workspace_root,
            repos,
            remote: None,
            scans: Vec::new(),
            remote_summary: None,
            remote_pending: None,
            remote_error: None,
            last_scan: None,
            rescan_requested: true,
            pending: None,
            render_dirty: false,
            theme: Theme::default(),
        }
    }

    /// Thin-mode constructor: the scan runs on the server (it holds the cloned
    /// repos at `<root>/<ws>/git/<member>`), reached over the `Viz.Knowledge`
    /// RPC. `workspace_root`/`repos` are only used for the displayed labels here.
    pub fn new_remote(
        workspace_root: PathBuf,
        repos: Vec<String>,
        endpoint: String,
        token: String,
        workspace: String,
    ) -> Self {
        let mut s = Self::new(workspace_root, repos);
        s.remote = Some(RemoteSrc { endpoint, token, workspace });
        s
    }

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

    /// Re-scope to a different workspace (the picker switched): swap in the new
    /// root + repo list, drop the stale scans, and arm a fresh background rescan
    /// so the next `draw()` rebuilds the map for the new workspace.
    pub fn set_workspace(&mut self, workspace_root: PathBuf, repos: Vec<String>) {
        self.workspace_root = workspace_root;
        self.repos = repos;
        // In thin mode the RPC is workspace-scoped: re-point its header so the
        // server scans the newly selected workspace's checkouts.
        if let Some(r) = self.remote.as_mut() {
            // The viz drives the picker; the workspace name comes from app.rs via
            // `set_workspace_name` below (so the root/repos labels and the RPC
            // header stay in sync). Default to keeping the prior name here.
            let _ = r;
        }
        self.scans.clear();
        self.remote_summary = None;
        self.remote_pending = None;
        self.remote_error = None;
        self.last_scan = None;
        self.pending = None;
        self.rescan_requested = true;
        self.render_dirty = false;
    }

    /// Thin mode only: re-point the `Viz.Knowledge` RPC at a new workspace (the
    /// picker switched). No-op when local. Call this alongside `set_workspace`.
    pub fn set_workspace_name(&mut self, workspace: String) {
        if let Some(r) = self.remote.as_mut() {
            r.workspace = workspace;
        }
    }

    /// Kick off a background fetch of the server-side knowledge scan over the
    /// `Viz.Knowledge` RPC (thin mode). Returns immediately; the UI never blocks.
    fn start_remote_scan(&mut self, r: RemoteSrc) {
        let slot: RemoteSlot = Arc::new(Mutex::new(None));
        let sink = slot.clone();
        trace::emit_in(
            "knowledge.scan",
            &ScanIn {
                workspace_root: format!("remote {} (ws={})", r.endpoint, r.workspace),
                repos: self.repos.clone(),
            },
        );
        std::thread::spawn(move || {
            let res = super::remote::knowledge_summary(&r.endpoint, &r.token, &r.workspace)
                .map_err(|e| format!("{e:#}"));
            *sink.lock().unwrap_or_else(|p| p.into_inner()) = Some(res);
        });
        self.remote_pending = Some((slot, Instant::now()));
    }

    /// Kick off a background scan of all configured repos. Returns immediately;
    /// the UI thread never blocks. The spawned thread fans out across repos with
    /// rayon (slowest-scan, not sum-of-scans) and parks the result in the slot.
    fn start_scan(&mut self) {
        // Thin mode: the scan runs on the server (it owns the checkouts).
        if let Some(r) = self.remote.clone() {
            self.start_remote_scan(r);
            return;
        }
        let slot: ScanSlot = Arc::new(Mutex::new(None));
        let sink = slot.clone();
        let workspace_root = self.workspace_root.clone();
        let repos = self.repos.clone();
        // Structured observability (see viz::trace): emit the INPUT (the
        // workspace_root + the repo list this scan was handed). The per-repo
        // OUTPUT + the scan OUT summary are emitted from the worker thread.
        trace::emit_in(
            "knowledge.scan",
            &ScanIn {
                workspace_root: workspace_root.display().to_string(),
                repos: repos.clone(),
            },
        );
        std::thread::spawn(move || {
            use rayon::prelude::*;
            let t0 = Instant::now();
            let scans: Vec<(String, Result<ScanResult, String>)> = repos
                .par_iter()
                .map(|repo| {
                    let repo_root = workspace_root.join(repo);
                    let exists = repo_root.exists();
                    let r0 = Instant::now();
                    let scan = knowledge::scan_all(&repo_root, repo).map_err(|e| format!("{e:#}"));
                    let result = match &scan {
                        Ok(s) => RepoScan {
                            repo: repo.clone(),
                            path: repo_root.display().to_string(),
                            exists,
                            symbols: s.symbols.symbols.len(),
                            calls: s.symbols.calls.len(),
                            features: s.symbols.features.len(),
                            git_files: s.git.files.len(),
                            ms: r0.elapsed().as_millis() as u64,
                            error: None,
                        },
                        Err(e) => RepoScan {
                            repo: repo.clone(),
                            path: repo_root.display().to_string(),
                            exists,
                            symbols: 0,
                            calls: 0,
                            features: 0,
                            git_files: 0,
                            ms: r0.elapsed().as_millis() as u64,
                            error: Some(e.clone()),
                        },
                    };
                    // The OUTPUT data for this repo, structured (a missing path or
                    // a case-mismatch shows as exists=false + an error string).
                    trace::emit_end("knowledge.scan.repo", &result);
                    (repo.clone(), scan)
                })
                .collect();
            let ok = scans.iter().filter(|(_, s)| s.is_ok()).count();
            trace::emit_out(
                "knowledge.scan",
                &ScanOut {
                    repos_ok: ok,
                    repos_total: scans.len(),
                    ms: t0.elapsed().as_millis() as u64,
                },
            );
            *sink.lock().unwrap_or_else(|p| p.into_inner()) = Some(scans);
        });
        self.pending = Some((slot, Instant::now()));
    }

    /// Run the scan synchronously and store the result — **test-only** injector
    /// for the inject-and-assert harness (no UI loop to drain the background
    /// slot). After this `scans` / `state_json` carry the real counts.
    #[doc(hidden)]
    pub fn scan_blocking_for_test(&mut self) {
        use rayon::prelude::*;
        let workspace_root = &self.workspace_root;
        self.scans = self
            .repos
            .par_iter()
            .map(|repo| {
                let repo_root = workspace_root.join(repo);
                let scan = knowledge::scan_all(&repo_root, repo).map_err(|e| format!("{e:#}"));
                (repo.clone(), scan)
            })
            .collect();
        self.last_scan = Some(Instant::now());
        self.rescan_requested = false;
        self.pending = None;
        self.render_dirty = true;
    }

    /// Drain a finished remote `Viz.Knowledge` fetch into `remote_summary` /
    /// `remote_error`. Lock-poison tolerant (the worker thread may have unwound).
    fn drain_remote(&mut self) {
        if let Some((slot, _started)) = &self.remote_pending {
            let done = slot.lock().unwrap_or_else(|p| p.into_inner()).take();
            if let Some(res) = done {
                match res {
                    Ok(summary) => {
                        self.remote_summary = Some(summary);
                        self.remote_error = None;
                    }
                    Err(e) => self.remote_error = Some(e),
                }
                self.last_scan = Some(Instant::now());
                self.remote_pending = None;
                self.render_dirty = true;
            }
        }
    }

    /// The bubbles to render this frame: the server's summary in thin mode, else
    /// the locally-collected ones from `scans`.
    fn current_bubbles(&self) -> Vec<Bubble> {
        match &self.remote_summary {
            Some(s) => s.crates.clone(),
            None => collect_bubbles(&self.scans),
        }
    }

    /// True while either a local scan or a remote fetch is in flight.
    fn is_scanning(&self) -> bool {
        self.pending.is_some() || self.remote_pending.is_some()
    }

    pub fn draw(&mut self, ui: &mut egui::Ui) {
        let theme = self.theme;
        // Drain a finished background scan into `scans` (recover a poisoned lock
        // rather than panic the UI thread if the worker unwound mid-flight).
        if let Some((slot, _started)) = &self.pending {
            let done = slot.lock().unwrap_or_else(|p| p.into_inner()).take();
            if let Some(scans) = done {
                self.scans = scans;
                self.last_scan = Some(Instant::now());
                self.pending = None;
                self.render_dirty = true;
            }
        }
        self.drain_remote();
        // First entry / rescan / workspace switch: arm the background scan. We
        // don't kick a new one while one is already in flight.
        if self.rescan_requested && !self.is_scanning() {
            self.start_scan();
            self.rescan_requested = false;
        }

        let scanning = self.is_scanning();
        ui.horizontal(|ui| {
            ui.heading("🗺 Knowledge map");
            ui.separator();
            if ui.add_enabled(!scanning, egui::Button::new("↻ rescan")).clicked() {
                self.rescan_requested = true;
            }
            let started = self
                .pending
                .as_ref()
                .map(|(_, t)| *t)
                .or(self.remote_pending.as_ref().map(|(_, t)| *t));
            if let Some(started) = started {
                let where_ = if self.remote.is_some() { "server" } else { "local" };
                ui.label(format!(
                    "⏳ scanning {} repo(s) [{where_}] … {}s",
                    self.repos.len(),
                    started.elapsed().as_secs()
                ));
                // Keep the frame loop alive so we notice the worker finishing.
                ui.ctx().request_repaint();
            } else if let Some(when) = self.last_scan {
                ui.label(format!("last scanned {}s ago", when.elapsed().as_secs()));
            }
        });
        if let Some(err) = &self.remote_error {
            ui.colored_label(Color32::RED, format!("Viz.Knowledge failed: {err}"));
        }
        ui.separator();

        let bubbles = self.current_bubbles();
        // The rendered table/chart payload — the EXACT rows the user sees on
        // screen, as structured data. This is the "see the data we see" event:
        // an agent reads this back to know precisely what the Knowledge tab
        // displayed (which repos, which crates, the counts), no screenshot.
        // Edge-triggered (only after a rescan) so it never floods the per-frame
        // redraw loop.
        if self.render_dirty {
            trace::emit_end(
                "knowledge.render",
                &RenderOut { crates: bubbles.len(), bubbles: &bubbles },
            );
            self.render_dirty = false;
        }
        if bubbles.is_empty() {
            if scanning {
                ui.label("⏳ scanning repos (symbol parse + git heat) — the UI stays responsive …");
            } else {
                ui.label("No data yet — click ↻ rescan or check workspace path.");
            }
            return;
        }

        // Header table of per-crate totals.
        egui::CollapsingHeader::new(format!("📊 {} crates scanned", bubbles.len()))
            .default_open(true)
            .show(ui, |ui| {
                egui::Grid::new("kn_summary").striped(true).num_columns(7).show(ui, |ui| {
                    ui.label("repo"); ui.label("crate");
                    ui.label("symbols"); ui.label("calls"); ui.label("files");
                    ui.label("gates"); ui.label("git heat (30d)");
                    ui.end_row();
                    for b in &bubbles {
                        ui.label(&b.repo); ui.label(&b.krate);
                        ui.label(format!("{}", b.symbols));
                        ui.label(format!("{}", b.calls));
                        ui.label(format!("{}", b.files));
                        ui.label(format!("{}", b.gates));
                        ui.label(format!("{}", b.heat_30d));
                        ui.end_row();
                    }
                });
            });

        ui.separator();
        ui.label("Bubble chart — x: symbol count, y: call count, size: files, color: 30d commits");
        draw_bubble_chart(ui, &bubbles, &theme);
    }

    /// The Knowledge tab's slice of `state_json` — the exact rendered rows (one
    /// per crate), the scan status, and per-repo totals. Mirrors what the UI
    /// paints so the headless test matrix / an agent reads back the real data
    /// (LAW #6: the rendered rows are in `state_json`).
    pub fn state_json(&self) -> serde_json::Value {
        let bubbles = self.current_bubbles();
        // Remote mode renders from the server's summary; local from `scans`.
        let (repos, scanned_repos): (Vec<serde_json::Value>, usize) =
            if let Some(s) = &self.remote_summary {
                let v = s
                    .repos
                    .iter()
                    .map(|r| {
                        if r.ok {
                            serde_json::json!({
                                "repo": r.repo, "ok": true,
                                "symbols": r.symbols, "calls": r.calls,
                                "features": r.features, "git_files": r.git_files,
                            })
                        } else {
                            serde_json::json!({ "repo": r.repo, "ok": false, "error": r.error })
                        }
                    })
                    .collect();
                (v, s.repos.len())
            } else {
                let v = self
                    .scans
                    .iter()
                    .map(|(repo, scan)| match scan {
                        Ok(s) => serde_json::json!({
                            "repo": repo,
                            "ok": true,
                            "symbols": s.symbols.symbols.len(),
                            "calls": s.symbols.calls.len(),
                            "features": s.symbols.features.len(),
                            "git_files": s.git.files.len(),
                        }),
                        Err(e) => serde_json::json!({ "repo": repo, "ok": false, "error": e }),
                    })
                    .collect();
                (v, self.scans.len())
            };
        serde_json::json!({
            "workspace_root": self.workspace_root.display().to_string(),
            "configured_repos": self.repos,
            "source": if self.remote.is_some() { "remote" } else { "local" },
            "scanning": self.is_scanning(),
            "error": self.remote_error,
            "scanned_repos": scanned_repos,
            "crates": bubbles.len(),
            "rows": bubbles,
            "repo_totals": repos,
            "palette": self.theme.name,
        })
    }

    /// Test hook (thin mode): inject a decoded `Viz.Knowledge` summary directly,
    /// exactly as if the RPC fetch had returned it — so a headless test can
    /// assert `state_json()` renders the server's bubbles without a live server.
    #[doc(hidden)]
    pub fn inject_remote_summary_for_test(&mut self, summary: KnowledgeSummary) {
        self.remote_summary = Some(summary);
        self.remote_error = None;
        self.remote_pending = None;
        self.rescan_requested = false;
        self.last_scan = Some(Instant::now());
    }
}

/// One per-crate bubble — the exact row the Knowledge map renders. Shared
/// between the local scan path and the remote `Viz.Knowledge` decode, so a thin
/// client renders the identical bubbles the embedded scan produces.
#[derive(Serialize, Deserialize, Clone)]
pub struct Bubble {
    pub repo: String,
    pub krate: String,
    pub symbols: usize,
    pub calls: usize,
    pub files: usize,
    pub gates: usize,
    pub heat_30d: i64,
}

/// One per-repo scan summary (mirrors the embedded `state_json` per-repo block) —
/// the server emits these so the remote tab shows the same `repo_totals` rows.
#[derive(Serialize, Deserialize, Clone)]
pub struct RepoScanSummary {
    pub repo: String,
    pub ok: bool,
    #[serde(default)]
    pub symbols: usize,
    #[serde(default)]
    pub calls: usize,
    #[serde(default)]
    pub features: usize,
    #[serde(default)]
    pub git_files: usize,
    #[serde(default)]
    pub error: Option<String>,
}

/// The whole knowledge-map summary a `Viz.Knowledge` response carries: the
/// per-repo scan rollups + the per-crate bubbles. Built server-side by
/// [`scan_summary_json`] from raw [`ScanResult`]s and decoded client-side into a
/// [`RemoteKnowledge`] the tab renders.
#[derive(Serialize, Deserialize, Clone, Default)]
pub struct KnowledgeSummary {
    pub repos: Vec<RepoScanSummary>,
    pub crates: Vec<Bubble>,
}

/// Build the [`KnowledgeSummary`] JSON the `Viz.Knowledge` RPC returns from raw
/// per-repo scans. Same `collect_bubbles` + per-repo rollup the embedded tab
/// computes, so server and embedded render byte-identical maps. Public so
/// `nornir-server` (same crate, `viz` feature) can call it.
pub fn scan_summary_json(scans: &[(String, Result<ScanResult, String>)]) -> serde_json::Value {
    let crates = collect_bubbles(scans);
    let repos: Vec<RepoScanSummary> = scans
        .iter()
        .map(|(repo, scan)| match scan {
            Ok(s) => RepoScanSummary {
                repo: repo.clone(),
                ok: true,
                symbols: s.symbols.symbols.len(),
                calls: s.symbols.calls.len(),
                features: s.symbols.features.len(),
                git_files: s.git.files.len(),
                error: None,
            },
            Err(e) => RepoScanSummary {
                repo: repo.clone(),
                ok: false,
                error: Some(e.clone()),
                ..Default::default()
            },
        })
        .collect();
    serde_json::to_value(KnowledgeSummary { repos, crates }).unwrap_or_default()
}

impl Default for RepoScanSummary {
    fn default() -> Self {
        Self {
            repo: String::new(),
            ok: false,
            symbols: 0,
            calls: 0,
            features: 0,
            git_files: 0,
            error: None,
        }
    }
}

fn collect_bubbles(scans: &[(String, Result<ScanResult, String>)]) -> Vec<Bubble> {
    let mut out = Vec::new();
    for (repo, scan) in scans {
        let Ok(scan) = scan else { continue };

        let mut per_crate_syms: BTreeMap<&str, usize> = BTreeMap::new();
        let mut per_crate_calls: BTreeMap<&str, usize> = BTreeMap::new();
        let mut per_crate_files: BTreeMap<&str, std::collections::BTreeSet<&str>> = BTreeMap::new();
        let mut per_crate_gates: BTreeMap<&str, usize> = BTreeMap::new();
        for s in &scan.symbols.symbols {
            *per_crate_syms.entry(&s.crate_name).or_default() += 1;
            per_crate_files.entry(&s.crate_name).or_default().insert(&s.file);
        }
        for c in &scan.symbols.calls {
            *per_crate_calls.entry(&c.crate_name).or_default() += 1;
        }
        for f in &scan.symbols.features {
            *per_crate_gates.entry(&f.crate_name).or_default() += 1;
        }

        // Heat: max 30d commits across all files in the repo, applied per-crate
        // (we lack module→crate mapping in git_heat, so use repo-wide max as a
        // simple proxy; refine later by joining file prefixes with crate dirs).
        let max_30d = scan.git.files.iter().map(|f| f.commits_30d).max().unwrap_or(0);

        for (krate, sym_n) in &per_crate_syms {
            out.push(Bubble {
                repo: repo.clone(),
                krate: krate.to_string(),
                symbols: *sym_n,
                calls: per_crate_calls.get(krate).copied().unwrap_or(0),
                files: per_crate_files.get(krate).map(|s| s.len()).unwrap_or(0),
                gates: per_crate_gates.get(krate).copied().unwrap_or(0),
                heat_30d: max_30d,
            });
        }
    }
    out.sort_by_key(|b| std::cmp::Reverse(b.symbols));
    out
}

fn draw_bubble_chart(ui: &mut egui::Ui, bubbles: &[Bubble], theme: &Theme) {
    let avail = ui.available_size_before_wrap();
    let plot_w = avail.x.max(400.0);
    let plot_h = (avail.y - 40.0).max(300.0);
    let (rect, _resp) = ui.allocate_exact_size(Vec2::new(plot_w, plot_h), Sense::hover());
    let painter = ui.painter_at(rect);

    painter.rect_filled(rect, 4.0, theme.bg);

    let max_sym = bubbles.iter().map(|b| b.symbols).max().unwrap_or(1) as f32;
    let max_calls = bubbles.iter().map(|b| b.calls).max().unwrap_or(1) as f32;
    let max_files = bubbles.iter().map(|b| b.files).max().unwrap_or(1) as f32;
    let max_heat = bubbles.iter().map(|b| b.heat_30d).max().unwrap_or(1) as f32;

    let pad = 30.0;
    for b in bubbles {
        let x_frac = ((b.symbols as f32).max(1.0).ln()) / max_sym.max(1.0).ln().max(0.1);
        let y_frac = ((b.calls as f32).max(1.0).ln()) / max_calls.max(1.0).ln().max(0.1);
        let cx = rect.min.x + pad + (rect.width() - 2.0 * pad) * x_frac;
        let cy = rect.max.y - pad - (rect.height() - 2.0 * pad) * y_frac;
        let r = 6.0 + 28.0 * ((b.files as f32) / max_files.max(1.0)).sqrt();
        let heat_norm = (b.heat_30d as f32) / max_heat.max(1.0);
        let color = theme.heat(heat_norm);

        painter.circle_filled(Pos2::new(cx, cy), r, color);
        painter.circle_stroke(Pos2::new(cx, cy), r, Stroke::new(1.0, theme.node_stroke));
        painter.text(
            Pos2::new(cx, cy - r - 6.0),
            egui::Align2::CENTER_BOTTOM,
            &b.krate,
            egui::FontId::proportional(10.0),
            theme.text,
        );
    }

    // Axis labels
    painter.text(
        Pos2::new(rect.center().x, rect.max.y - 4.0),
        egui::Align2::CENTER_BOTTOM,
        "symbols (log) →",
        egui::FontId::proportional(11.0),
        theme.text_dim,
    );
    painter.text(
        Pos2::new(rect.min.x + 4.0, rect.center().y),
        egui::Align2::LEFT_CENTER,
        "↑ calls (log)",
        egui::FontId::proportional(11.0),
        theme.text_dim,
    );
}

#[allow(dead_code)]
fn _path_only(_: &Path) {}

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

    /// LAW #1: thin-mode Knowledge renders the server's scan summary as REAL rows.
    /// Inject a decoded `Viz.Knowledge` summary (as the RPC fetch would deliver)
    /// and assert `state_json` carries crates>0 + the exact per-crate counts — the
    /// precise inverse of the `crates:0, workspace_root:""` empty-remote bug.
    #[test]
    fn remote_summary_renders_nonempty_rows() {
        let mut st = KnowledgeState::new_remote(
            PathBuf::from("/remote/holger/git"),
            vec!["znippy".into()],
            "http://server:7878".into(),
            "tok".into(),
            "holger".into(),
        );
        // Before any fetch the remote map is empty (no local checkout to scan).
        let before = st.state_json();
        assert_eq!(before["crates"], 0, "no data before the RPC returns");
        assert_eq!(before["source"], "remote");

        // The server replied with one crate (znippy: 120 symbols, 88 calls).
        st.inject_remote_summary_for_test(KnowledgeSummary {
            repos: vec![RepoScanSummary {
                repo: "znippy".into(),
                ok: true,
                symbols: 120,
                calls: 88,
                features: 3,
                git_files: 40,
                error: None,
            }],
            crates: vec![Bubble {
                repo: "znippy".into(),
                krate: "znippy".into(),
                symbols: 120,
                calls: 88,
                files: 40,
                gates: 3,
                heat_30d: 7,
            }],
        });

        let js = st.state_json();
        assert_eq!(js["crates"], 1, "remote map must render the server's crate");
        assert_eq!(js["rows"][0]["krate"], "znippy");
        assert_eq!(js["rows"][0]["symbols"], 120);
        assert_eq!(js["rows"][0]["calls"], 88);
        assert_eq!(js["repo_totals"][0]["repo"], "znippy");
        assert_eq!(js["repo_totals"][0]["git_files"], 40);
        assert_eq!(js["scanned_repos"], 1);
        assert_eq!(js["error"], serde_json::Value::Null);
    }

    /// `scan_summary_json` (the server's builder) → `KnowledgeSummary` (the client
    /// decode) preserves a failed-repo rollup with its error, so the remote tab
    /// can show a per-repo failure (e.g. a missing checkout) the same way local
    /// does — not silently drop it.
    #[test]
    fn scan_summary_carries_repo_errors() {
        let scans: Vec<(String, Result<ScanResult, String>)> =
            vec![("ghost".into(), Err("no such repo dir".into()))];
        let v = scan_summary_json(&scans);
        let summary: KnowledgeSummary = serde_json::from_value(v).unwrap();
        assert_eq!(summary.repos.len(), 1);
        assert!(!summary.repos[0].ok);
        assert_eq!(summary.repos[0].error.as_deref(), Some("no such repo dir"));
        assert!(summary.crates.is_empty(), "a failed repo contributes no bubbles");
    }
}