3 files changed, 148 insertions, 0 deletions
diff --git a/web-timeplot/src/data/base-source.js b/web-timeplot/src/data/base-source.js
new file mode 100644
index 0000000..55dbdc3
--- /dev/null
+++ b/web-timeplot/src/data/base-source.js
@@ -0,0 +1,21 @@
+export class BaseSource {
+    constructor(config = {}) {
+        this.config = { ...config };
+        this.running = false;
+    }
+
+    start() {
+        this.running = true;
+    }
+
+    stop() {
+        this.running = false;
+    }
+
+    updateConfig(nextConfig) {
+        this.config = {
+            ...this.config,
+            ...nextConfig,
+        };
+    }
+}
diff --git a/web-timeplot/src/data/source-registry.js b/web-timeplot/src/data/source-registry.js
new file mode 100644
index 0000000..06f5895
--- /dev/null
+++ b/web-timeplot/src/data/source-registry.js
@@ -0,0 +1,41 @@
+import { SyntheticWaveSource } from './synthetic-wave-source.js';
+
+export class SourceRegistry {
+    constructor(store, bus) {
+        this.store = store;
+        this.bus = bus;
+        this.sources = new Map([
+            ['synthetic-wave', new SyntheticWaveSource(store.getState().source)],
+        ]);
+        this.activeSource = this.sources.get(store.getState().source.activeId);
+        this.activeSource.start(store.getState().time.plotTimeMs);
+    }
+
+    syncFromState() {
+        const state = this.store.getState();
+        const nextSource = this.sources.get(state.source.activeId);
+
+        if (nextSource !== this.activeSource) {
+            this.activeSource?.stop();
+            this.activeSource = nextSource;
+            this.activeSource?.start(state.time.plotTimeMs);
+        }
+
+        this.activeSource?.updateConfig(state.source);
+    }
+
+    update(currentPlotTimeMs) {
+        if (!this.activeSource) {
+            return;
+        }
+
+        const points = this.activeSource.update(currentPlotTimeMs);
+        for (const point of points) {
+            this.bus.emit('data:point', point);
+        }
+    }
+
+    reset() {
+        this.activeSource?.reset(this.store.getState().time.plotTimeMs);
+    }
+}
diff --git a/web-timeplot/src/data/synthetic-wave-source.js b/web-timeplot/src/data/synthetic-wave-source.js
new file mode 100644
index 0000000..3cf7fb1
--- /dev/null
+++ b/web-timeplot/src/data/synthetic-wave-source.js
@@ -0,0 +1,86 @@
+import { BaseSource } from './base-source.js';
+
+function clamp(value, min, max) {
+    return Math.min(max, Math.max(min, value));
+}
+
+function createDeterministicNoise(seed) {
+    const x = Math.sin(seed * 12.9898) * 43758.5453;
+    return x - Math.floor(x);
+}
+
+export class SyntheticWaveSource extends BaseSource {
+    constructor(config = {}) {
+        super({
+            sampleRateHz: 60,
+            preset: 'telemetry',
+            amplitude: 1,
+            noise: 0.08,
+            ...config,
+        });
+        this.lastEmittedPlotTimeMs = 0;
+    }
+
+    start(startTimeMs = 0) {
+        super.start();
+        this.lastEmittedPlotTimeMs = startTimeMs;
+    }
+
+    stop() {
+        super.stop();
+    }
+
+    reset(startTimeMs = 0) {
+        this.lastEmittedPlotTimeMs = startTimeMs;
+    }
+
+    sampleValue(timeMs) {
+        const seconds = timeMs / 1000;
+        const amplitude = this.config.amplitude;
+        const noise = this.config.noise;
+        const grain = (createDeterministicNoise(timeMs * 0.017) - 0.5) * 2 * noise;
+
+        switch (this.config.preset) {
+            case 'chirp': {
+                const sweep = Math.sin(seconds * seconds * 1.4);
+                return amplitude * (0.7 * sweep + 0.3 * Math.sin(seconds * 7.5)) + grain;
+            }
+            case 'burst': {
+                const burstPhase = (seconds % 6) - 1.5;
+                const burst = Math.sin(seconds * 9.5) * Math.exp(-(burstPhase ** 2) * 0.8);
+                return amplitude * (0.45 * Math.sin(seconds * 2.1) + burst) + grain;
+            }
+            case 'telemetry':
+            default: {
+                const carrier = Math.sin(seconds * 2.2);
+                const secondary = 0.35 * Math.cos(seconds * 6.4 + Math.sin(seconds * 0.8));
+                const envelope = 0.15 * Math.sin(seconds * 0.33);
+                return amplitude * (carrier + secondary + envelope) + grain;
+            }
+        }
+    }
+
+    update(currentPlotTimeMs) {
+        if (!this.running) {
+            return [];
+        }
+
+        const intervalMs = 1000 / clamp(this.config.sampleRateHz, 1, 240);
+        if (currentPlotTimeMs < this.lastEmittedPlotTimeMs) {
+            this.lastEmittedPlotTimeMs = currentPlotTimeMs;
+            return [];
+        }
+
+        const points = [];
+        while (this.lastEmittedPlotTimeMs + intervalMs <= currentPlotTimeMs) {
+            this.lastEmittedPlotTimeMs += intervalMs;
+            points.push({
+                timeMs: this.lastEmittedPlotTimeMs,
+                value: this.sampleValue(this.lastEmittedPlotTimeMs),
+                sourceId: 'synthetic-wave',
+            });
+        }
+
+        return points;
+    }
+}