feat: Add currency conversion support for swaps

migrations.py

@@ -155,3 +155,40 @@ async def m005_fix_settings_table_drop_mempool(db):
     await db.execute("DROP TABLE boltz.settings")
     # NOTE using `boltz.settings` for the RENAME TO clause will not work in sqlite
     await db.execute("ALTER TABLE boltz.settings_backup RENAME TO settings")
+
+
+async def m006_add_currency_support(db):
+    """
+    Add currency support for fiat conversion in swaps.
+    Stores the currency used and the original display amount entered by user.
+    """
+    # Add currency columns (default to 'sats' for existing swaps)
+    await db.execute(
+        "ALTER TABLE boltz.submarineswap "
+        "ADD COLUMN currency TEXT NOT NULL DEFAULT 'sats'"
+    )
+    await db.execute(
+        "ALTER TABLE boltz.reverse_submarineswap "
+        "ADD COLUMN currency TEXT NOT NULL DEFAULT 'sats'"
+    )
+
+    # Add amount_display columns (stores original fiat amount entered by user)
+    # Using REAL type to store decimal values like 234.56 for fiat
+    await db.execute(
+        "ALTER TABLE boltz.submarineswap "
+        "ADD COLUMN amount_display REAL NOT NULL DEFAULT 0"
+    )
+    await db.execute(
+        "ALTER TABLE boltz.reverse_submarineswap "
+        "ADD COLUMN amount_display REAL NOT NULL DEFAULT 0"
+    )
+
+    # For existing rows, set amount_display = amount (they're all in sats)
+    await db.execute(
+        "UPDATE boltz.submarineswap "
+        "SET amount_display = amount WHERE amount_display = 0"
+    )
+    await db.execute(
+        "UPDATE boltz.reverse_submarineswap "
+        "SET amount_display = amount WHERE amount_display = 0"
+    )

models.py

@@ -30,6 +30,8 @@ class SubmarineSwap(BaseModel):
     bip21: str
     redeem_script: str
     blinding_key: str | None = None
+    currency: str = "sats"
+    amount_display: float = 0
 
 
 class CreateSubmarineSwap(BaseModel):
@@ -40,6 +42,8 @@ class CreateSubmarineSwap(BaseModel):
     direction: str = Query("receive")
     feerate: bool = Query(None)
     feerate_value: int | None = Query(None)
+    currency: str = Query("sats")
+    amount_display: float = Query(0)
 
 
 class ReverseSubmarineSwap(BaseModel):
@@ -63,6 +67,8 @@ class ReverseSubmarineSwap(BaseModel):
     timeout_block_height: int
     redeem_script: str
     blinding_key: str | None = None
+    currency: str = "sats"
+    amount_display: float = 0
 
 
 class CreateReverseSubmarineSwap(BaseModel):
@@ -74,6 +80,8 @@ class CreateReverseSubmarineSwap(BaseModel):
     onchain_address: str = Query(...)
     feerate: bool = Query(None)
     feerate_value: int | None = Query(None)
+    currency: str = Query("sats")
+    amount_display: float = Query(0)
 
 
 class AutoReverseSubmarineSwap(BaseModel):

templates/boltz/_reverseSubmarineSwapDialog.html

@@ -26,15 +26,32 @@
       >
       </q-select>
 
-      <q-input
-        filled
-        dense
-        emit-value
-        :label="amountLabel(reverseSubmarineSwapDialog.data.asset)"
-        v-model.trim="reverseSubmarineSwapDialog.data.amount"
-        type="number"
-        hint="Enter the amount you want to send (e.g., 100000 sats)"
-      ></q-input>
+      <div class="row">
+        <div class="col q-pr-sm">
+          <q-input
+            filled
+            dense
+            emit-value
+            v-model.number="reverseSubmarineSwapDialog.data.amount"
+            type="number"
+            label="Amount *"
+            :min="reverseSubmarineSwapDialog.data.currency === 'sats' ? '1' : '0.01'"
+            :step="reverseSubmarineSwapDialog.data.currency === 'sats' ? '1' : '0.01'"
+            :hint="getAmountHint('reverse')"
+          ></q-input>
+        </div>
+        <div class="col-auto" style="width: 100px">
+          <q-select
+            filled
+            dense
+            v-model="reverseSubmarineSwapDialog.data.currency"
+            :options="currencies"
+            :display-value="reverseSubmarineSwapDialog.data.currency || 'sats'"
+            label="Currency"
+            @update:model-value="updateFiatRate"
+          ></q-select>
+        </div>
+      </div>
       <div class="row">
         <div class="col">
           <q-option-group

templates/boltz/_submarineSwapDialog.html

@@ -26,15 +26,32 @@
       >
       </q-select>
 
-      <q-input
-        filled
-        dense
-        emit-value
-        v-model.trim="submarineSwapDialog.data.amount"
-        :label="amountLabel(submarineSwapDialog.data.asset)"
-        type="number"
-        hint="Enter the amount you want to convert (e.g., 100000 sats)"
-      ></q-input>
+      <div class="row">
+        <div class="col q-pr-sm">
+          <q-input
+            filled
+            dense
+            emit-value
+            v-model.number="submarineSwapDialog.data.amount"
+            type="number"
+            label="Amount *"
+            :min="submarineSwapDialog.data.currency === 'sats' ? '1' : '0.01'"
+            :step="submarineSwapDialog.data.currency === 'sats' ? '1' : '0.01'"
+            :hint="getAmountHint('submarine')"
+          ></q-input>
+        </div>
+        <div class="col-auto" style="width: 100px">
+          <q-select
+            filled
+            dense
+            v-model="submarineSwapDialog.data.currency"
+            :options="currencies"
+            :display-value="submarineSwapDialog.data.currency || 'sats'"
+            label="Currency"
+            @update:model-value="updateFiatRate"
+          ></q-select>
+        </div>
+      </div>
       <div class="row">
         <div class="col">
           <q-option-group

templates/boltz/index.html

@@ -56,12 +56,15 @@
           {value: 'receive', label: 'Receive specified Amount'}
         ],
         assetOptions: ['BTC/BTC', 'L-BTC/BTC'],
+        currencies: [],
+        fiatRates: {},
         submarineSwapDialog: {
           show: false,
           data: {
             asset: 'BTC/BTC',
             direction: 'receive',
-            feerate: false
+            feerate: false,
+            currency: 'sats'
           }
         },
         reverseSubmarineSwapDialog: {
@@ -70,7 +73,8 @@
             asset: 'BTC/BTC',
             direction: 'send',
             instant_settlement: true,
-            feerate: false
+            feerate: false,
+            currency: 'sats'
           }
         },
         autoReverseSubmarineSwapDialog: {
@@ -240,7 +244,13 @@
               name: 'amount',
               align: 'left',
               label: 'Amount',
-              field: 'amount'
+              field: 'amount',
+              format: (val, row) => {
+                if (row.currency && row.currency !== 'sats') {
+                  return `${row.amount_display} ${row.currency} (${val.toLocaleString()} sats)`
+                }
+                return `${val.toLocaleString()} sats`
+              }
             },
             {
               name: 'direction',
@@ -312,7 +322,13 @@
               name: 'amount',
               align: 'left',
               label: 'Amount',
-              field: 'amount'
+              field: 'amount',
+              format: (val, row) => {
+                if (row.currency && row.currency !== 'sats') {
+                  return `${row.amount_display} ${row.currency} (${val.toLocaleString()} sats)`
+                }
+                return `${val.toLocaleString()} sats`
+              }
             },
             {
               name: 'direction',
@@ -523,7 +539,8 @@
           data: {
             asset: 'BTC/BTC',
             direction: 'receive',
-            feerate: false
+            feerate: false,
+            currency: 'sats'
           }
         }
       },
@@ -538,7 +555,8 @@
             asset: 'BTC/BTC',
             direction: 'send',
             instant_settlement: true,
-            feerate: false
+            feerate: false,
+            currency: 'sats'
           }
         }
       },
@@ -566,7 +584,23 @@
           id: this.reverseSubmarineSwapDialog.data.wallet
         })
         let data = this.reverseSubmarineSwapDialog.data
-        this.createReverseSubmarineSwap(wallet, data)
+
+        // Store original amount entered by user
+        const amount_display = data.amount
+        const currency = data.currency || 'sats'
+
+        // Convert to sats for the API
+        const amount_sats = this.convertFiatToSats(data.amount, currency)
+
+        // Prepare data for API
+        const apiData = {
+          ...data,
+          amount: amount_sats, // Always send sats to API
+          amount_display: amount_display, // Original amount entered
+          currency: currency
+        }
+
+        this.createReverseSubmarineSwap(wallet, apiData)
       },
       sendAutoReverseSubmarineSwapFormData() {
         let wallet = _.findWhere(this.g.user.wallets, {
@@ -580,7 +614,23 @@
           id: this.submarineSwapDialog.data.wallet
         })
         let data = this.submarineSwapDialog.data
-        this.createSubmarineSwap(wallet, data)
+
+        // Store original amount entered by user
+        const amount_display = data.amount
+        const currency = data.currency || 'sats'
+
+        // Convert to sats for the API
+        const amount_sats = this.convertFiatToSats(data.amount, currency)
+
+        // Prepare data for API
+        const apiData = {
+          ...data,
+          amount: amount_sats, // Always send sats to API
+          amount_display: amount_display, // Original amount entered
+          currency: currency
+        }
+
+        this.createSubmarineSwap(wallet, apiData)
       },
       exportSubmarineSwapCSV() {
         LNbits.utils.exportCSV(
@@ -703,6 +753,53 @@
           })
           .catch(LNbits.utils.notifyApiError)
       },
+      loadCurrencies() {
+        // Use LNbits Core global currencies (respects admin settings)
+        const coreCurrencies =
+          this.g.allowedCurrencies.length > 0
+            ? this.g.allowedCurrencies
+            : this.g.currencies
+        this.currencies = ['sats', ...coreCurrencies]
+      },
+      updateFiatRate(currency) {
+        if (currency && currency !== 'sats') {
+          LNbits.api
+            .request('GET', '/api/v1/rate/' + currency, null)
+            .then(response => {
+              this.fiatRates[currency] = response.data.rate
+            })
+            .catch(err => {
+              console.error(`Failed to get rate for ${currency}:`, err)
+            })
+        }
+      },
+      getAmountHint(swapType) {
+        const dialog =
+          swapType === 'submarine'
+            ? this.submarineSwapDialog
+            : this.reverseSubmarineSwapDialog
+        const amount = dialog.data.amount
+        const currency = dialog.data.currency
+
+        if (!amount || !currency || currency === 'sats') {
+          return 'Enter the amount you want to convert'
+        }
+
+        const rate = this.fiatRates[currency]
+        if (!rate) {
+          return `Loading ${currency} exchange rate...`
+        }
+
+        const sats = Math.round(amount * rate)
+        return `${amount} ${currency} = ${sats.toLocaleString()} sats (actual conversion calculated at time of swap)`
+      },
+      convertFiatToSats(amount, currency) {
+        if (!currency || currency === 'sats') {
+          return Math.round(amount)
+        }
+        const rate = this.fiatRates[currency]
+        return rate ? Math.round(amount * rate) : 0
+      },
       getBoltzConfig() {
         LNbits.api
           .request('GET', '/boltz/api/v1/swap/boltz')
@@ -715,7 +812,20 @@
           })
       }
     },
+    watch: {
+      'submarineSwapDialog.data.currency'(newCurrency) {
+        if (newCurrency) {
+          this.updateFiatRate(newCurrency)
+        }
+      },
+      'reverseSubmarineSwapDialog.data.currency'(newCurrency) {
+        if (newCurrency) {
+          this.updateFiatRate(newCurrency)
+        }
+      }
+    },
     created() {
+      this.loadCurrencies()
       this.getBoltzConfig()
       this.getSubmarineSwap()
       this.getReverseSubmarineSwap()