Show energy cost on dashboard

app/config.py

@@ -121,7 +121,12 @@ class UIConfig(BaseModel):
     allow_resize: bool = True
     enable_transfer_burst_alert: bool = False
     enable_voltage_deviation_alert: bool = False
-    energy_cost_per_kwh: float = 0.0
+    energy_cost_per_kwh: float = Field(0.0, ge=0)
+
+    @field_validator("energy_cost_per_kwh", mode="after")
+    @classmethod
+    def round_energy_cost_per_kwh(cls, value: float) -> float:
+        return round(float(value), 4)
 
 
 class AppConfig(BaseModel):

app/routes/api_config.py

@@ -1,6 +1,7 @@
 """Configuration CRUD endpoints (UPS, SMTP, UI). All require session+CSRF for writes."""
 
 from fastapi import APIRouter, Depends, HTTPException, Request
+from pydantic import ValidationError
 
 from ..auth import require_session, require_session_and_csrf
 from ..config import SMTPConfig, UIConfig, UPSConfig
@@ -142,6 +143,9 @@ async def update_ui_config(
     for k, v in payload.items():
         if k in ui_dict:
             ui_dict[k] = v
-    new_ui = UIConfig(**ui_dict)
+    try:
+        new_ui = UIConfig(**ui_dict)
+    except ValidationError as e:
+        raise HTTPException(status_code=422, detail=e.errors())
     await config_manager.update_ui_config(new_ui)
     return {"message": "UI config updated", "ui": new_ui.model_dump()}

app/static/css/style.css

@@ -138,6 +138,9 @@
 .tile.hidden { display: none; }
 .tile.dragging { opacity: 0.5; border: 1px dashed var(--accent); }
 .tile.selected { outline: 2px solid var(--accent); }
+.tile .energy-summary { flex-direction: column; gap: 4px; text-align: center; }
+.tile .energy-summary .big-value { font-size: 18px; line-height: 1.2; }
+.tile .energy-cost { color: var(--success); font-size: 13px; font-weight: 700; }
 .tile-controls { position: absolute; top: 4px; right: 4px; display: flex; gap: 4px; }
 .tile-controls select {
   background: var(--surface-3);

app/static/js/dashboard.js

@@ -529,7 +529,7 @@ function initTilesFor(name, grid) {
     energyTile.dataset.tile = 'energy';
     energyTile.style.left = '12px';
     energyTile.style.top = '12px';
-    energyTile.innerHTML = `<h4>Energy Today</h4><div class="tile-body"><span class="big-value" data-energy-val>-- kWh</span></div>`;
+    energyTile.innerHTML = `<h4>Energy Today</h4><div class="tile-body energy-summary"><span class="big-value" data-energy-val>-- kWh</span><span class="energy-cost" data-energy-cost>--</span></div>`;
     const resizeHandle = document.createElement('div'); resizeHandle.className='tile-resize'; energyTile.appendChild(resizeHandle);
     grid.appendChild(energyTile);
   }
@@ -1194,11 +1194,19 @@ evtSource.onmessage = (e) => {
     }).catch(()=>{});
     if (uiCfg.show_energy) {
       fetch(apiUpsPath(meta.name, '/energy')).then(r => r.json()).then(data => {
-        if (!data || data.kwh_today == null) return;
         const card = getCard(meta.name);
         if (!card) return;
         const energyVal = card.querySelector('[data-energy-val]');
-        if (energyVal) energyVal.textContent = data.kwh_today.toFixed(2) + ' kWh';
+        const energyCost = card.querySelector('[data-energy-cost]');
+        if (!data || data.kwh_today == null) {
+          if (energyVal) energyVal.textContent = '-- kWh';
+          if (energyCost) energyCost.textContent = '--';
+          return;
+        }
+        if (energyVal) energyVal.textContent = `${Number(data.kwh_today).toFixed(4)} kWh`;
+        if (energyCost) {
+          energyCost.textContent = data.cost_today == null ? '--' : `$${Number(data.cost_today).toFixed(4)}`;
+        }
       }).catch(()=>{});
     }
   });

app/static/js/settings.js

@@ -1,5 +1,11 @@
 // Settings page
 (async function () {
+  function normalizeEnergyRate(value) {
+    const parsed = Number.parseFloat(value);
+    if (!Number.isFinite(parsed) || parsed < 0) return '0.0000';
+    return parsed.toFixed(4);
+  }
+
   async function loadUi() {
     const r = await window.apiFetch('/api/config/ui');
     if (!r.ok) return;
@@ -9,6 +15,7 @@
       const el = form.elements[k];
       if (!el) return;
       if (el.type === 'checkbox') el.checked = !!v;
+      else if (k === 'energy_cost_per_kwh') el.value = normalizeEnergyRate(v);
       else el.value = v;
     });
   }
@@ -37,7 +44,7 @@
       color_badges: f.color_badges.checked,
       enable_transfer_burst_alert: f.enable_transfer_burst_alert.checked,
       enable_voltage_deviation_alert: f.enable_voltage_deviation_alert.checked,
-      energy_cost_per_kwh: parseFloat(f.energy_cost_per_kwh.value) || 0,
+      energy_cost_per_kwh: Number.parseFloat(normalizeEnergyRate(f.energy_cost_per_kwh.value)),
     };
     const r = await window.apiFetch('/api/config/ui', {
       method: 'PUT', body: JSON.stringify(payload),

app/templates/base.html

@@ -6,7 +6,7 @@
   <title>{% block title %}UPS Dashboard{% endblock %}</title>
   <meta name="csrf-token" content="{{ request.cookies.get('csrf_token', '') }}" />
   <link rel="stylesheet" href="/static/css/base.css?v=5" />
-  <link rel="stylesheet" href="/static/css/style.css?v=5" />
+  <link rel="stylesheet" href="/static/css/style.css?v=6" />
   {% block head_extra %}{% endblock %}
 </head>
 <body>

app/templates/dashboard.html

@@ -61,5 +61,5 @@
 </div>
 {% endblock %}
 {% block scripts %}
-<script src="/static/js/dashboard.js?v=6"></script>
+<script src="/static/js/dashboard.js?v=7"></script>
 {% endblock %}

app/templates/settings.html

@@ -47,7 +47,7 @@
       </div>
       <div class="field-row">
         <label class="field-label" for="energy-cost">Energy cost per kWh ($)</label>
-        <input class="field-input" id="energy-cost" type="number" step="0.001" min="0" name="energy_cost_per_kwh">
+        <input class="field-input" id="energy-cost" type="number" step="0.0001" min="0" name="energy_cost_per_kwh" inputmode="decimal" placeholder="0.1365">
       </div>
       <div class="form-bar">
         <button type="submit" class="btn btn-primary">Save UI Settings</button>
@@ -116,5 +116,5 @@
 </div>
 {% endblock %}
 {% block scripts %}
-<script src="/static/js/settings.js?v=4"></script>
+<script src="/static/js/settings.js?v=5"></script>
 {% endblock %}

tests/test_api_routes.py

@@ -120,6 +120,23 @@ def test_ups_energy_with_data(authed_client, fake_redis):
     assert body["kwh_today"] == 1.0
 
 
+def test_ups_energy_uses_four_decimal_cost_rate(authed_client, fake_redis):
+    _add_ups(authed_client)
+    authed_client.put(
+        "/api/config/ui",
+        json={"show_energy": True, "energy_cost_per_kwh": 0.1365},
+    )
+    day_str = time.strftime("%Y%m%d")
+    fake_redis.set(f"ups:energy:u1:{day_str}", "7200000")  # 2 kWh
+
+    r = authed_client.get("/api/ups/u1/energy")
+
+    assert r.status_code == 200
+    body = r.json()
+    assert body["kwh_today"] == 2.0
+    assert body["cost_today"] == 0.273
+
+
 def test_ups_health(authed_client, fake_redis):
     _add_ups(authed_client)
     fake_redis.set("ups:health:last_ok:u1", "12345")

tests/test_config_api.py

@@ -133,3 +133,22 @@ def test_ui_config_update(authed_client):
     body = r.json()
     assert body["ui"]["show_energy"] is True
     assert body["ui"]["energy_cost_per_kwh"] == 0.15
+
+
+def test_ui_config_energy_cost_keeps_four_decimal_rate(authed_client):
+    r = authed_client.put(
+        "/api/config/ui",
+        json={"show_energy": True, "energy_cost_per_kwh": 0.13654},
+    )
+
+    assert r.status_code == 200
+    assert r.json()["ui"]["energy_cost_per_kwh"] == 0.1365
+
+
+def test_ui_config_rejects_negative_energy_cost(authed_client):
+    r = authed_client.put(
+        "/api/config/ui",
+        json={"energy_cost_per_kwh": -0.1},
+    )
+
+    assert r.status_code == 422