Internationalization + Finnish language (#181)

* I18n with next-intl

* package-lock

* Finnish translations

* Development fix

* Use locale for positioning currency symbol

* Translations: Expenses.ActiveUserModal

* Translations: group 404

* Better translation for ExpenseCard

* Apply translations in CategorySelect search

* Fix for Finnish translation

* Translations for ExpenseDocumentsInput

* Translations for CreateFromReceipt

* Fix for Finnish translation

* Translations for schema errors

* Fix for Finnish translation

* Fixes for Finnish translations

* Prettier

---------

Co-authored-by: Sebastien Castiel <sebastien@castiel.me>

src/lib/locale.ts

@@ -0,0 +1,42 @@
+'use server'
+
+import { Locale, Locales, defaultLocale, locales } from '@/i18n'
+import { match } from '@formatjs/intl-localematcher'
+import Negotiator from 'negotiator'
+import { cookies, headers } from 'next/headers'
+
+const COOKIE_NAME = 'NEXT_LOCALE'
+
+function getAcceptLanguageLocale(requestHeaders: Headers, locales: Locales) {
+  let locale
+  const languages = new Negotiator({
+    headers: {
+      'accept-language': requestHeaders.get('accept-language') || undefined,
+    },
+  }).languages()
+  try {
+    locale = match(languages, locales, defaultLocale)
+  } catch (e) {
+    // invalid language
+  }
+  return locale
+}
+
+export async function getUserLocale() {
+  let locale
+
+  // Prio 1: use existing cookie
+  locale = cookies().get(COOKIE_NAME)?.value
+
+  // Prio 2: use `accept-language` header
+  // Prio 3: use default locale
+  if (!locale) {
+    locale = getAcceptLanguageLocale(headers(), locales)
+  }
+
+  return locale
+}
+
+export async function setUserLocale(locale: Locale) {
+  cookies().set(COOKIE_NAME, locale)
+}

src/lib/schemas.ts

@@ -3,22 +3,13 @@ import * as z from 'zod'
 
 export const groupFormSchema = z
   .object({
-    name: z
-      .string()
-      .min(2, 'Enter at least two characters.')
-      .max(50, 'Enter at most 50 characters.'),
-    currency: z
-      .string()
-      .min(1, 'Enter at least one character.')
-      .max(5, 'Enter at most five characters.'),
+    name: z.string().min(2, 'min2').max(50, 'max50'),
+    currency: z.string().min(1, 'min1').max(5, 'max5'),
     participants: z
       .array(
         z.object({
           id: z.string().optional(),
-          name: z
-            .string()
-            .min(2, 'Enter at least two characters.')
-            .max(50, 'Enter at most 50 characters.'),
+          name: z.string().min(2, 'min2').max(50, 'max50'),
         }),
       )
       .min(1),
@@ -29,7 +20,7 @@ export const groupFormSchema = z
         if (otherParticipant.name === participant.name) {
           ctx.addIssue({
             code: 'custom',
-            message: 'Another participant already has this name.',
+            message: 'duplicateParticipantName',
             path: ['participants', i, 'name'],
           })
         }
@@ -42,9 +33,7 @@ export type GroupFormValues = z.infer<typeof groupFormSchema>
 export const expenseFormSchema = z
   .object({
     expenseDate: z.coerce.date(),
-    title: z
-      .string({ required_error: 'Please enter a title.' })
-      .min(2, 'Enter at least two characters.'),
+    title: z.string({ required_error: 'titleRequired' }).min(2, 'min2'),
     category: z.coerce.number().default(0),
     amount: z
       .union(
@@ -55,19 +44,16 @@ export const expenseFormSchema = z
             if (Number.isNaN(valueAsNumber))
               ctx.addIssue({
                 code: z.ZodIssueCode.custom,
-                message: 'Invalid number.',
+                message: 'invalidNumber',
               })
             return Math.round(valueAsNumber * 100)
           }),
         ],
-        { required_error: 'You must enter an amount.' },
+        { required_error: 'amountRequired' },
       )
-      .refine((amount) => amount != 1, 'The amount must not be zero.')
-      .refine(
-        (amount) => amount <= 10_000_000_00,
-        'The amount must be lower than 10,000,000.',
-      ),
-    paidBy: z.string({ required_error: 'You must select a participant.' }),
+      .refine((amount) => amount != 1, 'amountNotZero')
+      .refine((amount) => amount <= 10_000_000_00, 'amountTenMillion'),
+    paidBy: z.string({ required_error: 'paidByRequired' }),
     paidFor: z
       .array(
         z.object({
@@ -80,14 +66,14 @@ export const expenseFormSchema = z
               if (Number.isNaN(valueAsNumber))
                 ctx.addIssue({
                   code: z.ZodIssueCode.custom,
-                  message: 'Invalid number.',
+                  message: 'invalidNumber',
                 })
               return Math.round(valueAsNumber * 100)
             }),
           ]),
         }),
       )
-      .min(1, 'The expense must be paid for at least one participant.')
+      .min(1, 'paidForMin1')
       .superRefine((paidFor, ctx) => {
         let sum = 0
         for (const { shares } of paidFor) {
@@ -95,7 +81,7 @@ export const expenseFormSchema = z
           if (shares < 1) {
             ctx.addIssue({
               code: z.ZodIssueCode.custom,
-              message: 'All shares must be higher than 0.',
+              message: 'noZeroShares',
             })
           }
         }
@@ -138,7 +124,7 @@ export const expenseFormSchema = z
               : `${((sum - expense.amount) / 100).toFixed(2)} surplus`
           ctx.addIssue({
             code: z.ZodIssueCode.custom,
-            message: `Sum of amounts must equal the expense amount (${detail}).`,
+            message: 'amountSum',
             path: ['paidFor'],
           })
         }
@@ -152,7 +138,7 @@ export const expenseFormSchema = z
               : `${((sum - 10000) / 100).toFixed(0)}% surplus`
           ctx.addIssue({
             code: z.ZodIssueCode.custom,
-            message: `Sum of percentages must equal 100 (${detail})`,
+            message: 'percentageSum',
             path: ['paidFor'],
           })
         }

src/lib/utils.ts

@@ -15,9 +15,10 @@ export type DateTimeStyle = NonNullable<
 >['dateStyle']
 export function formatDate(
   date: Date,
+  locale: string,
   options: { dateStyle?: DateTimeStyle; timeStyle?: DateTimeStyle } = {},
 ) {
-  return date.toLocaleString('en-GB', {
+  return date.toLocaleString(locale, {
     ...options,
     timeZone: 'UTC',
   })
@@ -27,18 +28,25 @@ export function formatCategoryForAIPrompt(category: Category) {
   return `"${category.grouping}/${category.name}" (ID: ${category.id})`
 }
 
-export function formatCurrency(currency: string, amount: number) {
-  const format = new Intl.NumberFormat('en-US', {
+export function formatCurrency(
+  currency: string,
+  amount: number,
+  locale: string,
+) {
+  const format = new Intl.NumberFormat(locale, {
     minimumFractionDigits: 2,
     maximumFractionDigits: 2,
+    style: 'currency',
+    // '€' will be placed in correct position
+    currency: 'EUR',
   })
   const formattedAmount = format.format(amount / 100)
-  return `${currency} ${formattedAmount}`
+  return formattedAmount.replace('€', currency)
 }
 
-export function formatFileSize(size: number) {
+export function formatFileSize(size: number, locale: string) {
   const formatNumber = (num: number) =>
-    num.toLocaleString('en-US', {
+    num.toLocaleString(locale, {
       minimumFractionDigits: 0,
       maximumFractionDigits: 1,
     })