Add UK MPG fuel consumption unit

messages/en.json

@@ -45,6 +45,7 @@
   "settings_desc_mileage_format": "Choose how fuel efficiency is displayed",
   "settings_mileage_format_distance_per_fuel": "Distance per Fuel (e.g., km/L, mpg)",
   "settings_mileage_format_fuel_per_distance": "Fuel per Distance (e.g., L/100km)",
+  "settings_mileage_format_uk_mpg": "UK MPG (miles per imperial gallon)",
   "settings_desc_theme": "Choose your preferred theme",
   "settings_desc_custom_css": "CSS Styles for customizing the interface",
   "settings_select_language": "Select language",

src/lib/components/feature/settings/SettingsModal.svelte

@@ -50,7 +50,7 @@
     unitOfLpg: z.enum(['liter', 'gallon', 'kilogram', 'pound']).default('liter'),
     unitOfCng: z.enum(['liter', 'gallon', 'kilogram', 'pound']).default('kilogram'),
     mileageUnitFormat: z
-      .enum(['distance-per-fuel', 'fuel-per-distance'])
+      .enum(['distance-per-fuel', 'fuel-per-distance', 'uk-mpg'])
       .default('distance-per-fuel'),
     theme: z.string().default('light'),
     customCss: z.string().optional(),
@@ -177,6 +177,10 @@
     {
       value: 'fuel-per-distance',
       label: m.settings_mileage_format_fuel_per_distance()
+    },
+    {
+      value: 'uk-mpg',
+      label: m.settings_mileage_format_uk_mpg()
     }
   ];
 

src/lib/helper/format.helper.ts

@@ -210,6 +210,15 @@ const getMileageUnit = (vehicleType: string): string => {
     return `${fuelLabel}/100${distanceUnit}`;
   }
 
+  // only show uk mpg if miles and liters are used
+  if (
+    configs.mileageUnitFormat === 'uk-mpg' &&
+    configs.unitOfDistance === 'mile' &&
+    fuelUnit === 'liter'
+  ) {
+    return 'mpg';
+  }
+
   // Default: distance-per-fuel (e.g., km/L, mpg)
   const mileageUnit = `${configs.unitOfDistance}-per-${fuelUnit}`;
   const label = safeUnitLabel(mileageUnit);
@@ -230,6 +239,15 @@ const formatMileage = (mileage: number, vehicleType: string): string => {
     return `${mileage.toFixed(2)} ${fuelLabel}/100${distanceUnit}`;
   }
 
+  // only show uk mpg if miles and liters are used
+  if (
+    configs.mileageUnitFormat === 'uk-mpg' &&
+    configs.unitOfDistance === 'mile' &&
+    fuelUnit === 'liter'
+  ) {
+    return `${mileage.toFixed(2)} mpg`;
+  }
+
   // Default: distance-per-fuel (e.g., km/L, mpg)
   const mileageUnit = `${configs.unitOfDistance}-per-${fuelUnit}`;
   return (

src/lib/helper/settings-form.helper.ts

@@ -25,28 +25,33 @@ export function createSettingsConfigSchema(
   isValidTimezone: (value: string) => boolean,
   options: SettingsSchemaOptions = {}
 ) {
-  const baseSchema = z.object({
-    dateFormat: z.string().refine((fmt) => isValidFormat(fmt).valid, 'Format not valid'),
-    locale: z.string().min(2),
-    timezone: z.string().min(3).refine(isValidTimezone, 'Invalid timzone value.'),
-    currency: z.string().min(1, 'Currency is required'),
-    unitOfDistance: z.enum(['kilometer', 'mile']),
-    unitOfVolume: z.enum(['liter', 'gallon']),
-    unitOfLpg: z.enum(['liter', 'gallon', 'kilogram', 'pound']).default('liter'),
-    unitOfCng: z.enum(['liter', 'gallon', 'kilogram', 'pound']).default('kilogram'),
-    mileageUnitFormat: z
-      .enum(['distance-per-fuel', 'fuel-per-distance'])
-      .default('distance-per-fuel'),
-    theme: z.string().default('light'),
-    customCss: z.string().optional(),
-    featureFuelLog: z.boolean().default(true),
-    featureMaintenance: z.boolean().default(true),
-    featurePucc: z.boolean().default(true),
-    featureReminders: z.boolean().default(true),
-    featureInsurance: z.boolean().default(true),
-    featureOverview: z.boolean().default(true),
-    notificationProcessingEnabled: z.boolean().default(true)
-  });
+  const baseSchema = z
+    .object({
+      dateFormat: z.string().refine((fmt) => isValidFormat(fmt).valid, 'Format not valid'),
+      locale: z.string().min(2),
+      timezone: z.string().min(3).refine(isValidTimezone, 'Invalid timzone value.'),
+      currency: z.string().min(1, 'Currency is required'),
+      unitOfDistance: z.enum(['kilometer', 'mile']),
+      unitOfVolume: z.enum(['liter', 'gallon']),
+      unitOfLpg: z.enum(['liter', 'gallon', 'kilogram', 'pound']).default('liter'),
+      unitOfCng: z.enum(['liter', 'gallon', 'kilogram', 'pound']).default('kilogram'),
+      mileageUnitFormat: z
+        .enum(['distance-per-fuel', 'fuel-per-distance', 'uk-mpg'])
+        .default('distance-per-fuel'),
+      theme: z.string().default('light'),
+      customCss: z.string().optional(),
+      featureFuelLog: z.boolean().default(true),
+      featureMaintenance: z.boolean().default(true),
+      featurePucc: z.boolean().default(true),
+      featureReminders: z.boolean().default(true),
+      featureInsurance: z.boolean().default(true),
+      featureOverview: z.boolean().default(true),
+      notificationProcessingEnabled: z.boolean().default(true)
+    })
+    .refine((obj) => {
+      if (obj.mileageUnitFormat !== 'uk-mpg') return true;
+      return obj.unitOfDistance === 'mile' && obj.unitOfVolume === 'liter';
+    }, 'UK MPG calculation requires unit of distance to be miles and unit of volume to be litres.');
 
   if (!options.includeNotificationProcessingSchedule) {
     return baseSchema;
@@ -108,6 +113,10 @@ export function createSettingsOptions(
       {
         value: 'fuel-per-distance',
         label: m.settings_mileage_format_fuel_per_distance()
+      },
+      {
+        value: 'uk-mpg',
+        label: m.settings_mileage_format_uk_mpg()
       }
     ],
     localeOptions: locales.map((code) => ({

src/lib/types/settings.ts

@@ -7,7 +7,7 @@ export interface SettingsFormShape extends Record<string, unknown> {
   unitOfVolume: 'liter' | 'gallon';
   unitOfLpg: 'liter' | 'gallon' | 'kilogram' | 'pound';
   unitOfCng: 'liter' | 'gallon' | 'kilogram' | 'pound';
-  mileageUnitFormat: 'distance-per-fuel' | 'fuel-per-distance';
+  mileageUnitFormat: 'distance-per-fuel' | 'fuel-per-distance' | 'uk-mpg';
   theme: string;
   customCss?: string;
   featureFuelLog: boolean;

src/server/services/fuelLogService.ts

@@ -40,6 +40,16 @@ export const getFuelLogs = async (vehicleId: string): Promise<ApiResponse> => {
   const mileageFormatConfig = await db.query.configTable.findFirst({
     where: (config, { eq }) => eq(config.key, 'mileageUnitFormat')
   });
+  const distanceUnit = (
+    await db.query.configTable.findFirst({
+      where: (config, { eq }) => eq(config.key, 'unitOfDistance')
+    })
+  )?.value;
+  const volumeUnit = (
+    await db.query.configTable.findFirst({
+      where: (config, { eq }) => eq(config.key, 'unitOfVolume')
+    })
+  )?.value;
   const mileageFormat = mileageFormatConfig?.value || 'distance-per-fuel';
 
   const fuelLogs = await db.query.fuelLogTable.findMany({
@@ -102,6 +112,9 @@ export const getFuelLogs = async (vehicleId: string): Promise<ApiResponse> => {
     if (mileageFormat === 'fuel-per-distance') {
       // Fuel per 100 distance units (e.g., L/100km, gal/100mi)
       mileage = (totalFuel / distance) * 100;
+    } else if (mileageFormat === 'uk-mpg' && distanceUnit === 'mile' && volumeUnit === 'liter') {
+      // Miles per imperial gallon (mpg)
+      mileage = (distance / totalFuel) * 4.546;
     } else {
       // Distance per fuel unit (e.g., km/L, mpg) - default
       mileage = distance / totalFuel;