adding velocity control

main.go

@@ -165,7 +165,7 @@ var torrentFields = []string{
 
 type rpcRequest struct {
 	Method    string      `json:"method"`
-	Arguments rpcArgs     `json:"arguments"`
+	Arguments interface{} `json:"arguments"`
 	Tag       interface{} `json:"tag,omitempty"`
 }
 
@@ -179,6 +179,16 @@ type rpcResponse struct {
 	Args   json.RawMessage `json:"arguments"`
 }
 
+var sessionFields = []string{
+	"alt-speed-enabled", "alt-speed-down", "alt-speed-up",
+	"speed-limit-down-enabled", "speed-limit-down",
+	"speed-limit-up-enabled", "speed-limit-up", "units",
+}
+
+type sessionSetArgs struct {
+	AltSpeedEnabled bool `json:"alt-speed-enabled"`
+}
+
 func (c *Client) Torrents(ctx context.Context) (json.RawMessage, error) {
 	reqBody, _ := json.Marshal(rpcRequest{
 		Method:    "torrent-get",
@@ -216,6 +226,44 @@ func (c *Client) Stats(ctx context.Context) (json.RawMessage, error) {
 	return resp.Args, nil
 }
 
+func (c *Client) Session(ctx context.Context) (json.RawMessage, error) {
+	reqBody, _ := json.Marshal(rpcRequest{
+		Method:    "session-get",
+		Arguments: rpcArgs{Fields: sessionFields},
+	})
+	data, err := c.rpc(ctx, reqBody)
+	if err != nil {
+		return nil, err
+	}
+	var resp rpcResponse
+	if err := json.Unmarshal(data, &resp); err != nil {
+		return nil, err
+	}
+	if resp.Result != "success" {
+		return nil, fmt.Errorf("rpc result: %s", resp.Result)
+	}
+	return resp.Args, nil
+}
+
+func (c *Client) SetAlternativeSpeed(ctx context.Context, enabled bool) error {
+	reqBody, _ := json.Marshal(rpcRequest{
+		Method:    "session-set",
+		Arguments: sessionSetArgs{AltSpeedEnabled: enabled},
+	})
+	data, err := c.rpc(ctx, reqBody)
+	if err != nil {
+		return err
+	}
+	var resp rpcResponse
+	if err := json.Unmarshal(data, &resp); err != nil {
+		return err
+	}
+	if resp.Result != "success" {
+		return fmt.Errorf("rpc result: %s", resp.Result)
+	}
+	return nil
+}
+
 func (c *Client) TorrentAction(ctx context.Context, method string, ids []int) error {
 	reqBody, _ := json.Marshal(rpcRequest{
 		Method:    method,
@@ -450,6 +498,38 @@ func handleTorrentAction(client *Client, setupErr error) http.HandlerFunc {
 	}
 }
 
+func handleAlternativeSpeed(client *Client, setupErr error) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodPost {
+			w.Header().Set("Allow", http.MethodPost)
+			writeError(w, http.StatusMethodNotAllowed, "method not allowed")
+			return
+		}
+		if !requireTransmissionClient(w, client, setupErr) {
+			return
+		}
+
+		var payload struct {
+			Enabled *bool `json:"enabled"`
+		}
+		decoder := json.NewDecoder(io.LimitReader(r.Body, 1024))
+		if err := decoder.Decode(&payload); err != nil || payload.Enabled == nil {
+			writeError(w, http.StatusBadRequest, "request body must include a boolean enabled field")
+			return
+		}
+		if err := decoder.Decode(&struct{}{}); err != io.EOF {
+			writeError(w, http.StatusBadRequest, "request body must contain one JSON object")
+			return
+		}
+		if err := client.SetAlternativeSpeed(r.Context(), *payload.Enabled); err != nil {
+			log.Printf("alternative speed: %v", err)
+			writeError(w, http.StatusBadGateway, err.Error())
+			return
+		}
+		writeJSON(w, json.RawMessage(`{"ok":true}`))
+	}
+}
+
 func handleStaticFiles(fileServer http.Handler, client *Client, setupErr error) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		if r.Method == http.MethodGet && (r.URL.Path == "/" || r.URL.Path == "/index.html") {
@@ -509,6 +589,24 @@ func main() {
 		}
 		writeJSON(w, args)
 	})
+	mux.HandleFunc("/api/session", func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodGet {
+			w.Header().Set("Allow", http.MethodGet)
+			writeError(w, http.StatusMethodNotAllowed, "method not allowed")
+			return
+		}
+		if !requireTransmissionClient(w, client, setupErr) {
+			return
+		}
+		args, err := client.Session(r.Context())
+		if err != nil {
+			log.Printf("session: %v", err)
+			writeError(w, http.StatusBadGateway, err.Error())
+			return
+		}
+		writeJSON(w, args)
+	})
+	mux.HandleFunc("/api/session/alternative-speed", handleAlternativeSpeed(client, setupErr))
 
 	// Static files from embedded web/ directory
 	webRoot, err := fs.Sub(webFS, "web")

project-context.md

@@ -22,11 +22,11 @@ The app is intentionally small: one Go binary serves both the API and embedded f
 ## Repository Organization
 
 - `main.go`: backend entrypoint. Owns the HTTP server, embedded static file serving, environment-driven Transmission RPC client configuration, session-ID handshake, connection warning page, JSON helpers, and API routes.
-- `web/index.html`: SPA shell. Defines the header, stats pills, filter input, sort buttons, list container, empty state, error state, footer, and script/style links.
+- `web/index.html`: SPA shell. Defines the header, stats pills, alternative-speed controls, filter input, sort buttons, list container, empty state, error state, footer, and script/style links.
 - `web/icon.svg`: editable vector source for the app icon.
 - `web/icon.png`: reusable raster app icon used by the SPA header and browser tab.
-- `web/app.js`: frontend application logic. Owns state, polling, fetch helpers, formatting, torrent classification, sorting, keyed DOM reconciliation, pause/resume actions, and event wiring.
+- `web/app.js`: frontend application logic. Owns state, polling, fetch helpers, formatting, session-limit presentation and alternative-speed toggling, torrent classification, sorting, keyed DOM reconciliation, pause/resume actions, and event wiring.
-- `web/styles.css`: all styling. Owns dark theme variables, layout, cards, badges, progress bars, action buttons, empty/error states, and responsive rules.
+- `web/styles.css`: all styling. Owns dark theme variables, layout, cards, badges, progress bars, action buttons, alternative-speed controls, empty/error states, and responsive rules.
 - `go.mod`: Go module declaration.
 - `Dockerfile`: multi-stage production build.
 - `README.md`: public project documentation, configuration guide, and deployment instructions.
@@ -38,13 +38,15 @@ The backend uses `net/http` with a single `http.ServeMux`. It exposes:
 
 - `GET /api/torrents`: sends Transmission `torrent-get` with the required torrent fields and returns the RPC `arguments` JSON directly.
 - `GET /api/stats`: sends Transmission `session-stats` and returns the RPC `arguments` JSON directly.
+- `GET /api/session`: sends Transmission `session-get` for alternative-speed state, normal and alternative speed limits, and speed-unit metadata; returns the RPC `arguments` JSON directly.
+- `POST /api/session/alternative-speed`: validates an `{"enabled": boolean}` body and sends Transmission `session-set` to toggle alternative speeds.
 - `POST /api/torrents/{id}/pause`: validates a positive numeric torrent id and sends `torrent-stop`.
 - `POST /api/torrents/{id}/resume`: validates a positive numeric torrent id and sends queue-respecting `torrent-start`.
 - `/`: checks the Transmission connection and serves a warning page with the connection error when setup fails; otherwise serves embedded files from `web/`.
 
 Transmission RPC calls must reuse the existing `Client.rpc` path so session-ID handling is consistent. The session ID is cached in `Client.sessionID` and guarded by `sync.Mutex`.
 
-API errors return JSON with an `error` string. Invalid torrent action methods should return `405`; invalid ids should return `400`; unknown action paths should return `404`; Transmission failures should return `502`.
+API errors return JSON with an `error` string. Invalid torrent action methods should return `405`; invalid ids or malformed alternative-speed bodies should return `400`; unknown action paths should return `404`; Transmission failures should return `502`.
 
 ## Transmission RPC Model
 
@@ -67,9 +69,11 @@ The UI definition of "peers at 100%" is an absolute count of `peers[]` entries w
 
 The UI availability value comes from Transmission's `availability` per-piece array. Render and sort it as a complete-copy estimate, treating `-1` entries as pieces available locally.
 
+Alternative-speed controls use the effective profile: alternative caps when `alt-speed-enabled` is true, otherwise enabled normal caps. Positive caps are displayed in the header; zero or negative values are treated as unrestricted.
+
 ## Frontend Architecture
 
-The frontend is a single page with module-level state in `web/app.js`. It polls on a user-selectable interval, defaults to 3 seconds, and fetches torrents and stats in parallel.
+The frontend is a single page with module-level state in `web/app.js`. It polls on a user-selectable interval, defaults to 3 seconds, and fetches torrents, stats, and session settings in parallel.
 
 Important patterns:
 

web/app.js

@@ -20,6 +20,7 @@ const TRANSMISSION_STATUSES = {
 const state = {
   torrents: [],
   stats: {},
+  session: null,
   filter: "",
   sortKey: "status",
   refreshMs: DEFAULT_REFRESH_MS,
@@ -31,6 +32,8 @@ const actionStates = new Map();
 let syncInFlight = false;
 let syncQueued = false;
 let refreshTimer = null;
+let speedControlPending = false;
+let speedControlError = null;
 
 const $ = (sel) => document.querySelector(sel);
 
@@ -63,6 +66,11 @@ async function loadStats() {
   state.stats = data || {};
 }
 
+async function loadSession() {
+  const data = await fetchJSON("/api/session");
+  state.session = data && typeof data === "object" ? data : null;
+}
+
 async function sync() {
   if (syncInFlight) {
     syncQueued = true;
@@ -72,8 +80,9 @@ async function sync() {
   syncInFlight = true;
   setSyncing(true);
   try {
-    await Promise.all([loadTorrents(), loadStats()]);
+    await Promise.all([loadTorrents(), loadStats(), loadSession()]);
     state.lastError = null;
+    speedControlError = null;
   } catch (err) {
     state.lastError = err.message || String(err);
   } finally {
@@ -143,6 +152,28 @@ async function runTorrentAction(id, action) {
   }
 }
 
+async function setAlternativeSpeed(enabled) {
+  if (speedControlPending || !state.session) return;
+  speedControlPending = true;
+  speedControlError = null;
+  renderHeader();
+
+  try {
+    await fetchJSON("/api/session/alternative-speed", {
+      method: "POST",
+      headers: { "Content-Type": "application/json" },
+      body: JSON.stringify({ enabled }),
+    });
+    await sync();
+    speedControlPending = false;
+    renderHeader();
+  } catch (err) {
+    speedControlError = err.message || String(err);
+    speedControlPending = false;
+    renderHeader();
+  }
+}
+
 /* ---------- Formatting helpers ---------- */
 function humanSize(bytes) {
   if (bytes == null || isNaN(bytes) || bytes < 0) return "—";
@@ -337,6 +368,64 @@ function renderHeader() {
   $("#stat-torrents").textContent = String(torrents.length);
   $("#stat-dl").textContent = humanSpeed(dl);
   $("#stat-ul").textContent = humanSpeed(ul);
+  renderSpeedControls();
+}
+
+function sessionValue(session, kebab, snake) {
+  if (!session) return null;
+  if (session[kebab] != null) return session[kebab];
+  return snake ? session[snake] : null;
+}
+
+function sessionSpeedBytes(session) {
+  const units = session && session.units;
+  const value = units && (units["speed-bytes"] ?? units.speed_bytes ?? units.speedBytes);
+  return Number.isFinite(Number(value)) && Number(value) > 0 ? Number(value) : 1000;
+}
+
+function activeSpeedCap(session, direction) {
+  const enabled = Boolean(sessionValue(session, "alt-speed-enabled", "alt_speed_enabled"));
+  const alt = direction === "down"
+    ? sessionValue(session, "alt-speed-down", "alt_speed_down")
+    : sessionValue(session, "alt-speed-up", "alt_speed_up");
+  const normalEnabled = Boolean(sessionValue(
+    session,
+    direction === "down" ? "speed-limit-down-enabled" : "speed-limit-up-enabled",
+    direction === "down" ? "speed_limit_down_enabled" : "speed_limit_up_enabled",
+  ));
+  const normal = direction === "down"
+    ? sessionValue(session, "speed-limit-down", "speed_limit_down")
+    : sessionValue(session, "speed-limit-up", "speed_limit_up");
+  const value = enabled ? alt : (normalEnabled ? normal : null);
+  const number = Number(value);
+  return Number.isFinite(number) && number > 0 ? number * sessionSpeedBytes(session) : null;
+}
+
+function renderSpeedControls() {
+  const toggle = $("#alt-speed-toggle");
+  const toggleState = $("#alt-speed-state");
+  const status = $("#speed-control-status");
+  if (!toggle || !toggleState || !status) return;
+
+  const session = state.session;
+  const enabled = Boolean(sessionValue(session, "alt-speed-enabled", "alt_speed_enabled"));
+  toggle.disabled = !session || speedControlPending;
+  toggle.setAttribute("aria-pressed", String(enabled));
+  toggle.classList.toggle("is-saving", speedControlPending);
+  setText(toggleState, !session ? (state.lastError ? "Unavailable" : "Loading...") : (speedControlPending ? "Saving..." : (enabled ? "On" : "Off")));
+
+  const caps = [
+    { id: "speed-cap-down", value: activeSpeedCap(session, "down") },
+    { id: "speed-cap-up", value: activeSpeedCap(session, "up") },
+  ];
+  for (const cap of caps) {
+    const el = $("#" + cap.id);
+    if (!el) continue;
+    el.classList.toggle("hidden", cap.value == null);
+    const valueEl = el.querySelector("strong");
+    if (valueEl && cap.value != null) setText(valueEl, humanSpeed(cap.value));
+  }
+  setText(status, speedControlError || "");
 }
 
 function initial(name) {
@@ -611,6 +700,14 @@ function wireEvents() {
     });
   }
 
+  const speedToggle = $("#alt-speed-toggle");
+  if (speedToggle) {
+    speedToggle.addEventListener("click", () => {
+      const enabled = !Boolean(sessionValue(state.session, "alt-speed-enabled", "alt_speed_enabled"));
+      setAlternativeSpeed(enabled);
+    });
+  }
+
   $("#torrents").addEventListener("click", (e) => {
     const button = e.target.closest("[data-action-button]");
     if (!button || button.disabled) return;

web/index.html

@@ -41,6 +41,18 @@
           <span class="stat-value" id="stat-ul">—</span>
         </div>
       </div>
+
+      <div class="speed-controls" id="speed-controls" aria-live="polite">
+        <button type="button" class="speed-toggle" id="alt-speed-toggle" aria-pressed="false" disabled>
+          <span class="speed-toggle-label">Alternative speed</span>
+          <span class="speed-toggle-state" id="alt-speed-state">Loading...</span>
+        </button>
+        <div class="speed-caps" id="speed-caps" aria-label="Active speed caps">
+          <span class="speed-cap hidden" id="speed-cap-down" title="Active download cap">↓ <span class="speed-cap-label">Down</span> <strong></strong></span>
+          <span class="speed-cap hidden" id="speed-cap-up" title="Active upload cap">↑ <span class="speed-cap-label">Up</span> <strong></strong></span>
+        </div>
+        <span class="speed-control-status" id="speed-control-status" role="status"></span>
+      </div>
     </div>
   </header>
 

web/styles.css

@@ -140,6 +140,61 @@ button { font-family: inherit; }
 .stat-pill.download .stat-ico { color: var(--accent); }
 .stat-pill.upload .stat-ico { color: var(--ok); }
 
+.speed-controls {
+  display: inline-flex;
+  align-items: center;
+  justify-content: flex-end;
+  gap: 8px;
+  min-width: 0;
+}
+.speed-toggle {
+  display: inline-flex;
+  align-items: center;
+  gap: 7px;
+  border: 1px solid var(--border-strong);
+  border-radius: 999px;
+  background: var(--bg-2);
+  color: var(--text-2);
+  cursor: pointer;
+  font-size: 11px;
+  font-weight: 700;
+  padding: 7px 11px;
+  white-space: nowrap;
+  transition: background .15s, border-color .15s, color .15s, opacity .15s;
+}
+.speed-toggle:hover:not(:disabled) { border-color: var(--border-hover); color: var(--text-0); }
+.speed-toggle[aria-pressed="true"] {
+  background: var(--accent-soft);
+  border-color: rgba(0, 212, 255, 0.3);
+  color: var(--accent);
+}
+.speed-toggle:disabled { cursor: wait; opacity: 0.6; }
+.speed-toggle-state {
+  color: var(--text-3);
+  font-size: 10px;
+  letter-spacing: 0.08em;
+  text-transform: uppercase;
+}
+.speed-toggle[aria-pressed="true"] .speed-toggle-state { color: var(--text-1); }
+.speed-caps { display: inline-flex; align-items: center; gap: 5px; min-width: 0; }
+.speed-cap {
+  display: inline-flex;
+  align-items: center;
+  gap: 4px;
+  border: 1px solid var(--border);
+  border-radius: 999px;
+  background: var(--bg-2);
+  color: var(--text-2);
+  font-size: 11px;
+  font-variant-numeric: tabular-nums;
+  padding: 6px 9px;
+  white-space: nowrap;
+}
+.speed-cap strong { color: var(--text-0); font-weight: 700; }
+.speed-cap:first-child { color: var(--accent); }
+.speed-cap:last-child { color: var(--ok); }
+.speed-control-status { color: var(--red); font-size: 11px; max-width: 180px; }
+
 /* ---------- Container / Toolbar ---------- */
 .container {
   max-width: var(--maxw);
@@ -470,6 +525,7 @@ button { font-family: inherit; }
 @media (max-width: 720px) {
   .header-inner { flex-wrap: wrap; padding: 12px 16px; gap: 12px; }
   .header-stats { width: 100%; }
+  .speed-controls { width: 100%; justify-content: flex-start; flex-wrap: wrap; }
   .stat-pill { padding: 5px 10px; font-size: 12px; }
   .container { padding: 16px 14px 36px; }
   .toolbar { gap: 8px; }
@@ -484,6 +540,7 @@ button { font-family: inherit; }
 @media (max-width: 440px) {
   .brand-text h1 { font-size: 15px; }
   .stat-pill .stat-label { display: none; }
+  .speed-control-status { max-width: 100%; width: 100%; }
   .card-top { flex-wrap: wrap; }
   .card-body { flex-basis: calc(100% - 42px); }
   .card-actions { width: 100%; flex-direction: row; justify-content: space-between; }