feat(ui): choose how a late payday is priced

Surfaces the pricing modes in the console: a selector plus a rate field on
both the create and edit dialogs, and a "Rate used" column in the ledger
showing the figure alongside where it came from, so a payout can be
explained without opening the database.

Pay-now becomes a dialog rather than a confirm. That is the moment an
operator is most likely to want a rate other than the contract's own —
entering a payment that happened weeks ago at a figure they already know —
and the choice has to be made before it settles, not after. It defaults to
the contract's mode, disables the rate field unless "Rate I enter" is
picked, and refuses to submit a manual mode with no rate. The success toast
now names the rate applied, and a refused payout still shows its reason.

The mode selector is disabled for sat-denominated contracts, where there is
no conversion to have an opinion about, and its hint says the setting only
applies to a payday already in the past — otherwise it reads as though it
governs every payout, which it does not.

Quasar UMD rules honoured: no self-closing tags, `${ }` delimiters,
`:style` bindings rather than a <style> block.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018jy52j9GRZ6XKa1Zt21LLj

docs/operations.md

@@ -42,6 +42,42 @@ left on the employee's wallet. It was never settled and expires on its own;
 that is the deliberate price of not pricing the period a second time just
 to run a balance check.
 
+## Pricing a back-dated period
+
+A period whose payday is **today or ahead** is priced by LNbits itself —
+`create_invoice(amount, currency)` does the conversion, and nothing here
+touches the network. Every pricing mode agrees in that case.
+
+A period whose payday is **in the past** is where the modes diverge:
+
+| mode | converts at | use when |
+|---|---|---|
+| `payday` (default) | BTC's value on the payday | the expense belongs to that date |
+| `current` | today's rate | the debt reads "we owe EUR 800, whenever it settles" |
+| `manual` | a rate you state (`100000` EUR/BTC) | the figure was agreed, not looked up |
+
+Set per contract; overridable per payout via `pricing_mode` / `manual_rate`
+on `pay-now`, which is how you enter one back-dated payment without editing
+the contract.
+
+Historical rates come from `rates.py` — Kraken's daily OHLC series first
+(one request covers every date in a backfill), CoinGecko by date as the
+fallback for currencies Kraken does not quote. **Not** from LNbits' own
+exchange providers: those are spot tickers with no date parameter, and the
+rate history behind the admin chart is RAM-only, single-currency and wiped
+on restart.
+
+Where payroll converts, it hands `create_invoice` a **sat** amount, because
+`create_invoice` always prices fiat itself and cannot be told a rate. The
+rate used and its source are recorded on the payout row either way — in
+`current` mode read back off the invoice LNbits priced, not recomputed.
+
+**A rate that cannot be established fails the period.** There is deliberately
+no fallback to today's rate: one that moved 30% since the payday would pay
+30% off and record nothing about it. The failure goes through the same
+retry-then-pause path as an underfunded wallet, and names the date and
+currency it could not price.
+
 ## What a failure does
 
 A failed period does **not** advance `periods_done`, so the next tick

static/js/index.js

@@ -15,6 +15,12 @@ const FREQUENCIES = [
   {value: 'yearly', label: 'Yearly'}
 ]
 
+const PRICING_MODES = [
+  {value: 'payday', label: "Rate on the payday"},
+  {value: 'current', label: "Rate at settlement"},
+  {value: 'manual', label: 'Rate I enter'}
+]
+
 const STATUS_COLOUR = {
   active: 'positive',
   paused: 'warning',
@@ -45,7 +51,11 @@ function emptyContract() {
     total_periods: 12,
     label: '',
     memo: '',
-    backfill: false
+    backfill: false,
+    // Only ever consulted for a payday in the past; for a payday today or
+    // ahead every mode collapses to LNbits' own live pricing.
+    pricing_mode: 'payday',
+    manual_rate: null
   }
 }
 
@@ -69,6 +79,14 @@ window.app = Vue.createApp({
       frequencyOptions: FREQUENCIES,
 
       contractDialog: {show: false, data: emptyContract(), saving: false},
+      payNowDialog: {
+        show: false,
+        contract: null,
+        pricing_mode: 'payday',
+        manual_rate: null,
+        loading: false
+      },
+      pricingModes: PRICING_MODES,
       // Live calendar of whatever is currently typed into the dialog. The
       // cheapest moment to notice a wrong start date or frequency is before
       // anything is saved.
@@ -121,6 +139,7 @@ window.app = Vue.createApp({
           align: 'left',
           field: 'contract_id'
         },
+        {name: 'rate', label: 'Rate used', align: 'right', field: 'rate'},
         {name: 'attempt', label: 'Try', align: 'center', field: 'attempt'},
         {name: 'detail', label: 'Detail', align: 'left', field: 'detail'}
       ]
@@ -331,7 +350,9 @@ window.app = Vue.createApp({
           total_periods: d.open_ended ? null : Number(d.total_periods),
           label: d.label,
           memo: d.memo,
-          backfill: d.backfill
+          backfill: d.backfill,
+          pricing_mode: d.pricing_mode,
+          manual_rate: d.pricing_mode === 'manual' ? Number(d.manual_rate) : null
         })
         this.contractDialog.show = false
         Quasar.Notify.create({type: 'positive', message: 'Payroll line created'})
@@ -354,7 +375,9 @@ window.app = Vue.createApp({
           open_ended: contract.total_periods === null,
           total_periods: contract.total_periods,
           label: contract.label,
-          memo: contract.memo
+          memo: contract.memo,
+          pricing_mode: contract.pricing_mode,
+          manual_rate: contract.manual_rate
         }
       }
     },
@@ -372,7 +395,9 @@ window.app = Vue.createApp({
             frequency: d.frequency,
             total_periods: d.open_ended ? null : Number(d.total_periods),
             label: d.label,
-            memo: d.memo
+            memo: d.memo,
+            pricing_mode: d.pricing_mode,
+            manual_rate: d.pricing_mode === 'manual' ? Number(d.manual_rate) : null
           }
         )
         this.editDialog.show = false
@@ -416,16 +441,29 @@ window.app = Vue.createApp({
     },
 
     payNow(contract) {
-      LNbits.utils
+      // A dialog rather than a confirm: paying a back-dated period is
-        .confirmDialog(
+      // exactly when the operator may want a different rate than the
-          `Pay the next period of "${contract.label || contract.id}" now? ` +
+      // contract's own, and that choice has to be made before it settles.
-            'It is consumed even if its payday has not arrived yet.'
+      this.payNowDialog = {
-        )
+        show: true,
-        .onOk(async () => {
+        contract,
+        pricing_mode: contract.pricing_mode || 'payday',
+        manual_rate: contract.manual_rate,
+        loading: false
+      }
+    },
+
+    async confirmPayNow() {
+      const d = this.payNowDialog
+      const params = new URLSearchParams({pricing_mode: d.pricing_mode})
+      if (d.pricing_mode === 'manual' && d.manual_rate) {
+        params.append('manual_rate', String(d.manual_rate))
+      }
+      d.loading = true
       try {
         const {data} = await LNbits.api.request(
           'POST',
-              `${API}/contracts/${contract.id}/pay-now`
+          `${API}/contracts/${d.contract.id}/pay-now?${params.toString()}`
         )
         // A refused payout still returns a ledger row — surfacing its
         // reason is the whole point of triggering one by hand.
@@ -433,16 +471,19 @@ window.app = Vue.createApp({
           type: data.status === 'paid' ? 'positive' : 'negative',
           message:
             data.status === 'paid'
-                  ? `Paid ${Math.round(data.amount_msat / 1000)} sat`
+              ? `Paid ${Math.round(data.amount_msat / 1000)} sat` +
+                (data.rate ? ` at ${data.rate.toLocaleString()} / BTC` : '')
               : `Payout ${data.status}: ${data.detail}`,
-              timeout: data.status === 'paid' ? 3000 : 8000
+          timeout: data.status === 'paid' ? 4000 : 9000
         })
+        d.show = false
         this.getContracts()
         this.getPayouts()
       } catch (err) {
         this._err(err, 'Could not pay now')
+      } finally {
+        d.loading = false
       }
-        })
     },
 
     deleteContract(contract) {

templates/payroll/index.html

@@ -151,6 +151,18 @@
               </q-td>
             </template>
 
+            <template v-slot:body-cell-rate="props">
+              <q-td :props="props">
+                <span v-if="props.row.rate">
+                  ${ Math.round(props.row.rate).toLocaleString() }
+                  <span :style="{opacity: 0.6, fontSize: '0.8em'}">
+                    ${ props.row.rate_source }
+                  </span>
+                </span>
+                <span v-else :style="{opacity: 0.4}">—</span>
+              </q-td>
+            </template>
+
             <template v-slot:body-cell-detail="props">
               <q-td :props="props">
                 <span :style="{opacity: 0.75, fontSize: '0.85em'}">
@@ -252,6 +264,22 @@
       <q-input outlined dense v-model="contractDialog.data.memo"
         label="Payment memo" hint="What the employee sees on the payment"></q-input>
 
+      <div class="row q-col-gutter-sm">
+        <div class="col-7">
+          <q-select outlined dense v-model="contractDialog.data.pricing_mode"
+            :options="pricingModes" emit-value map-options
+            :disable="contractDialog.data.currency === 'sat'"
+            label="Price a late payday at"
+            hint="Only applies to a payday already in the past"></q-select>
+        </div>
+        <div class="col-5">
+          <q-input outlined dense type="number" step="any"
+            v-model.number="contractDialog.data.manual_rate"
+            :disable="contractDialog.data.pricing_mode !== 'manual'"
+            :label="'Rate (' + contractDialog.data.currency + '/BTC)'"></q-input>
+        </div>
+      </div>
+
       <q-toggle v-model="contractDialog.data.backfill"
         label="Pay paydays that already passed">
         <q-tooltip>
@@ -324,6 +352,19 @@
             label="Number of payments"></q-input>
         </div>
       </div>
+      <div class="row q-col-gutter-sm">
+        <div class="col-7">
+          <q-select outlined dense v-model="editDialog.data.pricing_mode"
+            :options="pricingModes" emit-value map-options
+            label="Price a late payday at"></q-select>
+        </div>
+        <div class="col-5">
+          <q-input outlined dense type="number" step="any"
+            v-model.number="editDialog.data.manual_rate"
+            :disable="editDialog.data.pricing_mode !== 'manual'"
+            label="Rate per BTC"></q-input>
+        </div>
+      </div>
       <q-input outlined dense v-model="editDialog.data.label" label="Label"></q-input>
       <q-input outlined dense v-model="editDialog.data.memo"
         label="Payment memo"></q-input>
@@ -335,6 +376,38 @@
   </q-card>
 </q-dialog>
 
+<!-- ==================================================== pay now -->
+<q-dialog v-model="payNowDialog.show">
+  <q-card style="width: 460px; max-width: 95vw">
+    <q-card-section>
+      <div class="text-h6">Pay the next period now</div>
+      <div v-if="payNowDialog.contract" class="text-caption"
+        :style="{opacity: 0.7}">
+        ${ payNowDialog.contract.label || payNowDialog.contract.employee_username }
+        — ${ payNowDialog.contract.amount } ${ payNowDialog.contract.currency }.
+        The period is consumed even if its payday has not arrived yet.
+      </div>
+    </q-card-section>
+    <q-card-section class="q-gutter-md">
+      <q-select outlined dense v-model="payNowDialog.pricing_mode"
+        :options="pricingModes" emit-value map-options
+        label="Price it at"
+        hint="Ignored unless the payday is already in the past"></q-select>
+      <q-input outlined dense type="number" step="any"
+        v-model.number="payNowDialog.manual_rate"
+        :disable="payNowDialog.pricing_mode !== 'manual'"
+        label="Rate per BTC"
+        hint="e.g. 100000 for 100,000 per BTC"></q-input>
+    </q-card-section>
+    <q-card-actions align="right">
+      <q-btn flat label="Cancel" v-close-popup></q-btn>
+      <q-btn color="primary" label="Pay now" :loading="payNowDialog.loading"
+        :disable="payNowDialog.pricing_mode === 'manual' && !payNowDialog.manual_rate"
+        @click="confirmPayNow"></q-btn>
+    </q-card-actions>
+  </q-card>
+</q-dialog>
+
 <!-- =================================================== schedule -->
 <q-dialog v-model="scheduleDialog.show">
   <q-card style="width: 420px; max-width: 95vw">