phase 10

web/src/lib/ws.ts

@@ -1,5 +1,5 @@
-import { readable, writable, type Readable } from './store';
-import type { SignalRef, SignalValue, SignalMeta } from './types';
+import { writable, type Readable } from './store';
+import type { SignalRef, SignalValue, SignalMeta, HistoryPoint } from './types';
 
 // ── Types ────────────────────────────────────────────────────────────────────
 
@@ -31,6 +31,8 @@ class WsClient {
   private refCounts = new Map<string, number>();
   // subscriber callbacks per signal
   private subscribers = new Map<string, Set<SubscriberEntry>>();
+  // pending history request callbacks keyed by "ds\0name"
+  private histCallbacks = new Map<string, Array<(pts: HistoryPoint[]) => void>>();
 
   connect(url: string): void {
     this.url = url;
@@ -146,7 +148,25 @@ class WsClient {
         for (const s of subs) s.onMeta(meta);
         break;
       }
+      case 'history': {
+        const hcbs = this.histCallbacks.get(key);
+        if (hcbs) {
+          const pts: HistoryPoint[] = (msg.points ?? []).map((p: any) => ({
+            ts: p.ts ?? p.TS,
+            value: p.value ?? p.Value,
+          }));
+          this.histCallbacks.delete(key);
+          for (const cb of hcbs) cb(pts);
+        }
+        break;
+      }
       case 'error':
+        // Resolve any pending history callbacks with empty data on error
+        if (key && this.histCallbacks.has(key)) {
+          const hcbs = this.histCallbacks.get(key)!;
+          this.histCallbacks.delete(key);
+          for (const cb of hcbs) cb([]);
+        }
         console.warn('[ws] server error', msg.code, msg.message);
         break;
       default:
@@ -197,6 +217,47 @@ class WsClient {
     };
   }
 
+  /**
+   * Request historical data for a signal.
+   * Resolves with an array of HistoryPoint once the server responds.
+   * Resolves with [] if the datasource doesn't support history or times out.
+   */
+  history(
+    ref: SignalRef,
+    start: string,
+    end: string,
+    maxPoints = 5000,
+  ): Promise<HistoryPoint[]> {
+    return new Promise((resolve) => {
+      const key = `${ref.ds}\0${ref.name}`;
+
+      // Timeout after 15 s — resolves with empty array
+      const timer = setTimeout(() => {
+        const cbs = this.histCallbacks.get(key);
+        if (cbs) {
+          const idx = cbs.indexOf(wrappedResolve);
+          if (idx >= 0) cbs.splice(idx, 1);
+          if (cbs.length === 0) this.histCallbacks.delete(key);
+        }
+        resolve([]);
+      }, 15_000);
+
+      const wrappedResolve = (pts: HistoryPoint[]) => {
+        clearTimeout(timer);
+        resolve(pts);
+      };
+
+      let cbs = this.histCallbacks.get(key);
+      if (!cbs) {
+        cbs = [];
+        this.histCallbacks.set(key, cbs);
+      }
+      cbs.push(wrappedResolve);
+
+      this._send({ type: 'history', ds: ref.ds, name: ref.name, start, end, maxPoints });
+    });
+  }
+
   write(ref: SignalRef, value: any): void {
     this._send({ type: 'write', ds: ref.ds, name: ref.name, value });
   }