CZK implemented

2026-06-23 12:54:11 +02:00
parent 6b7422806f
commit c409e85995
31 changed files with 606 additions and 51 deletions
--- a/assets/i18n/en/main.ftl
+++ b/assets/i18n/en/main.ftl
@@ -20,6 +20,7 @@ admin-audio-desc = upload songs, then group them into albums.
 logout = Log out
 settings = Settings
 settings-language = Language
+settings-currency = Currency
 settings-theme = Theme
 language-en = English
 language-sk = Slovak
@@ -475,6 +476,13 @@ bank-amount = Amount
 admin-shipping = Shipping
 admin-shipping-desc = set the price and availability of each delivery option.
 shipping-enabled = Active
+admin-currency = Currency
+admin-currency-desc = set the exchange rate for the currencies customers can switch between. You always enter prices in EUR.
+exchange-rate = Exchange rate
+exchange-rate-hint = { $code } prices are the { $base } price recalculated at this rate.
+currency-enabled = Available to customers
+currency-base = Base currency
+currency-base-hint = the currency you enter prices in and settle payment in. Cannot be changed.
 shipping-new = Add delivery option
 shipping-add = Add
 shipping-requires-pickup = Requires pickup point
--- a/assets/i18n/sk/main.ftl
+++ b/assets/i18n/sk/main.ftl
@@ -20,6 +20,7 @@ admin-audio-desc = nahrať skladby a potom ich zoskupiť do albumov.
 logout = Odhlásiť sa
 settings = Nastavenia
 settings-language = Jazyk
+settings-currency = Mena
 settings-theme = Téma
 language-en = Angličtina
 language-sk = Slovenčina
@@ -475,6 +476,13 @@ bank-amount = Suma
 admin-shipping = Doprava
 admin-shipping-desc = nastaviť cenu a dostupnosť jednotlivých možností dopravy.
 shipping-enabled = Aktívne
+admin-currency = Mena
+admin-currency-desc = nastaviť výmenný kurz pre meny, medzi ktorými môžu zákazníci prepínať. Ceny zadávate vždy v EUR.
+exchange-rate = Výmenný kurz
+exchange-rate-hint = ceny v { $code } sa prepočítajú z ceny v { $base } týmto kurzom.
+currency-enabled = Dostupná pre zákazníkov
+currency-base = Základná mena
+currency-base-hint = mena, v ktorej zadávate ceny a prebieha platba. Nedá sa zmeniť.
 shipping-new = Pridať možnosť dopravy
 shipping-add = Pridať
 shipping-requires-pickup = Vyžaduje výdajné miesto
--- a/assets/views/admin/base.html
+++ b/assets/views/admin/base.html
@@ -105,6 +105,10 @@
          class="flex items-center gap-2 rounded-radius px-2 py-1.5 text-sm font-medium text-on-surface underline-offset-2 transition hover:bg-primary/5 hover:text-on-surface-strong focus:outline-hidden focus-visible:underline aria-[current=page]:bg-primary/10 aria-[current=page]:text-on-surface-strong dark:text-on-surface-dark dark:hover:bg-primary-dark/5 dark:hover:text-on-surface-dark-strong dark:aria-[current=page]:bg-primary-dark/10 dark:aria-[current=page]:text-on-surface-dark-strong">
          {{ t(key="admin-shipping", lang=lang | default(value='sk')) }}
        </a>
+        <a href="/admin/currencies" data-nav="/admin/currencies"
+          class="flex items-center gap-2 rounded-radius px-2 py-1.5 text-sm font-medium text-on-surface underline-offset-2 transition hover:bg-primary/5 hover:text-on-surface-strong focus:outline-hidden focus-visible:underline aria-[current=page]:bg-primary/10 aria-[current=page]:text-on-surface-strong dark:text-on-surface-dark dark:hover:bg-primary-dark/5 dark:hover:text-on-surface-dark-strong dark:aria-[current=page]:bg-primary-dark/10 dark:aria-[current=page]:text-on-surface-dark-strong">
+          {{ t(key="admin-currency", lang=lang | default(value='sk')) }}
+        </a>
      </div>

      <div class="border-t border-outline p-4 dark:border-outline-dark">
--- a/assets/views/admin/currencies/index.html
+++ b/assets/views/admin/currencies/index.html
@@ -0,0 +1,44 @@
+{% extends "admin/base.html" %}
+{% import "macros/ui.html" as ui %}
+
+{% block title %}{{ t(key="admin-currency", lang=lang | default(value='sk')) }}{% endblock title %}
+{% block crumb %}{{ t(key="admin-currency", lang=lang | default(value='sk')) }}{% endblock crumb %}
+
+{% block content %}
+<header class="space-y-1">
+  <h1 class="text-2xl font-bold text-on-surface-strong dark:text-on-surface-dark-strong">{{ t(key="admin-currency", lang=lang | default(value='sk')) }}</h1>
+  <p class="text-sm text-on-surface/70 dark:text-on-surface-dark/70">{{ t(key="admin-currency-desc", lang=lang | default(value='sk')) }}</p>
+</header>
+
+<div class="mt-6 space-y-4">
+  <!-- base currency, read-only for context -->
+  <div class="flex flex-wrap items-center gap-4 rounded-radius border border-outline bg-surface-alt/40 p-5 dark:border-outline-dark dark:bg-surface-dark-alt/30">
+    <div class="min-w-40">
+      <p class="font-semibold text-on-surface-strong dark:text-on-surface-dark-strong">{{ base_code }} ({{ base_symbol }})</p>
+      <p class="text-xs text-on-surface/60 dark:text-on-surface-dark/60">{{ t(key="currency-base-hint", lang=lang | default(value='sk')) }}</p>
+    </div>
+    {{ ui::badge(label=t(key="currency-base", lang=lang | default(value='sk')), variant="neutral") }}
+  </div>
+
+  {% for c in currencies %}
+  <form method="post" action="/admin/currencies/{{ c.id }}"
+    class="flex flex-wrap items-end gap-4 rounded-radius border border-outline bg-surface p-5 dark:border-outline-dark dark:bg-surface-dark-alt">
+  {{ ui::csrf_field() }}
+    <div class="min-w-40">
+      <p class="font-semibold text-on-surface-strong dark:text-on-surface-dark-strong">{{ c.code }} ({{ c.symbol }})</p>
+      <p class="text-xs text-on-surface/60 dark:text-on-surface-dark/60">{{ t(key="exchange-rate-hint", code=c.code, base=base_code, lang=lang | default(value='sk')) }}</p>
+    </div>
+    <div class="space-y-1.5">
+      <label for="rate-{{ c.id }}" class="text-sm font-medium text-on-surface-strong dark:text-on-surface-dark-strong">{{ t(key="exchange-rate", lang=lang | default(value='sk')) }}</label>
+      <span class="flex items-center gap-2">
+        <span class="text-sm text-on-surface/60 dark:text-on-surface-dark/60">1 {{ base_code }} =</span>
+        {{ ui::input(name="rate", id="rate-" ~ c.id, value=c.rate, width="w-28", attrs='inputmode="decimal"') }}
+        <span class="text-sm text-on-surface/60 dark:text-on-surface-dark/60">{{ c.code }}</span>
+      </span>
+    </div>
+    <div class="pb-2">{{ ui::checkbox(name="enabled", label=t(key="currency-enabled", lang=lang | default(value='sk')), checked=c.enabled) }}</div>
+    {{ ui::button(label=t(key="save", lang=lang | default(value='sk')), type="submit", extra="ml-auto") }}
+  </form>
+  {% endfor %}
+</div>
+{% endblock content %}
--- a/assets/views/partials/settings_dropdown.html
+++ b/assets/views/partials/settings_dropdown.html
@@ -35,6 +35,27 @@
      {% if lang | default(value='sk') == "sk" %}<span class="text-primary dark:text-primary-dark">✓</span>{% endif %}
    </button>
  </form>
+  {# Currency switcher. The active code is read from the `currency` cookie
+     client-side (Alpine), so this partial needs no per-page server data; posting
+     to /currency sets the cookie and reloads. EUR is the base; CZK prices are the
+     EUR price recalculated at the admin-set rate. #}
+  <p class="mt-1 px-4 py-1.5 text-xs font-semibold uppercase tracking-wide text-on-surface/60 dark:text-on-surface-dark/60">
+    {{ t(key="settings-currency", lang=lang | default(value='sk')) }}
+  </p>
+  <form method="post" action="/currency" hx-boost="false"
+    x-data="{ cur: ((document.cookie.split('; ').find(function (c) { return c.indexOf('currency=') === 0 }) || 'currency=EUR').split('=')[1]) }">
+  <input type="hidden" name="_csrf" value="{{ csrf_token() }}">
+    <button type="submit" name="currency" value="EUR" role="menuitem"
+      class="flex w-full items-center justify-between px-4 py-2 text-sm text-on-surface transition hover:bg-primary/5 hover:text-on-surface-strong focus-visible:bg-primary/10 focus-visible:text-on-surface-strong focus-visible:outline-hidden dark:text-on-surface-dark dark:hover:bg-primary-dark/5 dark:hover:text-on-surface-dark-strong">
+      <span>EUR (€)</span>
+      <span x-cloak x-show="cur === 'EUR'" class="text-primary dark:text-primary-dark">✓</span>
+    </button>
+    <button type="submit" name="currency" value="CZK" role="menuitem"
+      class="flex w-full items-center justify-between px-4 py-2 text-sm text-on-surface transition hover:bg-primary/5 hover:text-on-surface-strong focus-visible:bg-primary/10 focus-visible:text-on-surface-strong focus-visible:outline-hidden dark:text-on-surface-dark dark:hover:bg-primary-dark/5 dark:hover:text-on-surface-dark-strong">
+      <span>CZK (Kč)</span>
+      <span x-cloak x-show="cur === 'CZK'" class="text-primary dark:text-primary-dark">✓</span>
+    </button>
+  </form>
  <p class="mt-1 px-4 py-1.5 text-xs font-semibold uppercase tracking-wide text-on-surface/60 dark:text-on-surface-dark/60">
    {{ t(key="settings-theme", lang=lang | default(value='sk')) }}
  </p>
--- a/assets/views/shop/_card.html
+++ b/assets/views/shop/_card.html
@@ -38,11 +38,11 @@
      {% endif %}
      {% if product.on_sale %}
      <div class="flex flex-wrap items-baseline gap-x-2 leading-tight">
-        <span class="text-xl font-semibold text-danger"><span class="sr-only">Price</span>{% if product.has_options %}{{ t(key="from-price", price=product.price, lang=lang | default(value='sk')) }}{% else %}{{ product.price }}{% endif %} €</span>
-        <span class="text-sm text-on-surface/50 line-through dark:text-on-surface-dark/50">{{ product.regular_price }} €</span>
+        <span class="text-xl font-semibold text-danger"><span class="sr-only">Price</span>{% if product.has_options %}{{ t(key="from-price", price=product.price, lang=lang | default(value='sk')) }}{% else %}{{ product.price }}{% endif %} {{ currency_symbol }}</span>
+        <span class="text-sm text-on-surface/50 line-through dark:text-on-surface-dark/50">{{ product.regular_price }} {{ currency_symbol }}</span>
      </div>
      {% else %}
-      <span class="break-words text-xl"><span class="sr-only">Price</span>{% if product.has_options %}{{ t(key="from-price", price=product.price, lang=lang | default(value='sk')) }}{% else %}{{ product.price }}{% endif %} €</span>
+      <span class="break-words text-xl"><span class="sr-only">Price</span>{% if product.has_options %}{{ t(key="from-price", price=product.price, lang=lang | default(value='sk')) }}{% else %}{{ product.price }}{% endif %} {{ currency_symbol }}</span>
      {% endif %}
    </div>
  </a>
--- a/assets/views/shop/_cart_body.html
+++ b/assets/views/shop/_cart_body.html
@@ -23,10 +23,10 @@
        </td>
        <td class="px-4 py-3 tabular-nums">
          {% if item.on_sale %}
-          <span class="font-medium text-danger">{{ item.price }} €</span>
+          <span class="font-medium text-danger">{{ item.price }} {{ currency_symbol }}</span>
          <span class="ml-1 text-xs text-on-surface/50 line-through dark:text-on-surface-dark/50">{{ item.regular_price }}</span>
          {% else %}
-          {{ item.price }} €
+          {{ item.price }} {{ currency_symbol }}
          {% endif %}
        </td>
        <td class="px-4 py-3">
@@ -48,7 +48,7 @@
              class="w-20 rounded-radius border border-outline bg-surface-alt px-2 py-1 text-sm text-on-surface focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-primary disabled:cursor-not-allowed disabled:opacity-75 dark:border-outline-dark dark:bg-surface-dark-alt/50 dark:text-on-surface-dark dark:focus-visible:outline-primary-dark">
          </form>
        </td>
-        <td class="px-4 py-3 text-right font-medium tabular-nums">{{ item.line_total }} €</td>
+        <td class="px-4 py-3 text-right font-medium tabular-nums">{{ item.line_total }} {{ currency_symbol }}</td>
        <td class="px-4 py-3 text-right">
          <form method="post" action="/cart/remove"
            hx-post="/cart/remove" hx-target="#cart-body" hx-swap="innerHTML">
@@ -63,7 +63,7 @@
    <tfoot class="{{ ui::tfoot_cls() }}">
      <tr>
        <td colspan="3" class="px-4 py-3 text-right font-semibold text-on-surface-strong dark:text-on-surface-dark-strong">{{ t(key="cart-total", lang=lang | default(value='sk')) }}</td>
-        <td class="px-4 py-3 text-right text-lg font-bold tabular-nums text-primary dark:text-primary-dark">{{ total }} €</td>
+        <td class="px-4 py-3 text-right text-lg font-bold tabular-nums text-primary dark:text-primary-dark">{{ total }} {{ currency_symbol }}</td>
        <td></td>
      </tr>
    </tfoot>
--- a/assets/views/shop/_cart_preview.html
+++ b/assets/views/shop/_cart_preview.html
@@ -9,16 +9,16 @@
    <div class="min-w-0 flex-1">
      <a href="/shop/{{ item.slug }}" class="block truncate text-sm font-medium text-on-surface-strong hover:text-primary dark:text-on-surface-dark-strong dark:hover:text-primary-dark">{{ item.name }}</a>
      {% if item.variant_label %}<span class="block truncate text-xs text-on-surface/60 dark:text-on-surface-dark/60">{{ item.variant_label }}</span>{% endif %}
-      <p class="mt-0.5 text-xs tabular-nums text-on-surface dark:text-on-surface-dark">{{ item.quantity }} × {{ item.price }} €</p>
+      <p class="mt-0.5 text-xs tabular-nums text-on-surface dark:text-on-surface-dark">{{ item.quantity }} × {{ item.price }} {{ currency_symbol }}</p>
    </div>
-    <span class="shrink-0 text-sm font-semibold tabular-nums text-on-surface-strong dark:text-on-surface-dark-strong">{{ item.line_total }} €</span>
+    <span class="shrink-0 text-sm font-semibold tabular-nums text-on-surface-strong dark:text-on-surface-dark-strong">{{ item.line_total }} {{ currency_symbol }}</span>
  </div>
  {% endfor %}
 </div>
 <div class="border-t border-outline px-4 py-3 dark:border-outline-dark">
  <div class="mb-3 flex items-center justify-between">
    <span class="text-sm text-on-surface dark:text-on-surface-dark">{{ t(key="cart-total", lang=lang | default(value='sk')) }}</span>
-    <span class="text-base font-bold tabular-nums text-primary dark:text-primary-dark">{{ total }} €</span>
+    <span class="text-base font-bold tabular-nums text-primary dark:text-primary-dark">{{ total }} {{ currency_symbol }}</span>
  </div>
  <div class="flex gap-2">
    {{ ui::button(href="/cart", variant="outline-primary", label=t(key="cart-title", lang=lang | default(value='sk')), extra="flex-1", attrs='hx-boost="false"') }}
--- a/assets/views/shop/_search.html
+++ b/assets/views/shop/_search.html
@@ -65,7 +65,7 @@

      <!-- price band -->
      <label class="flex flex-col gap-1 text-xs font-medium text-on-surface/70 dark:text-on-surface-dark/70">
-        {{ t(key="filter-price", lang=L) }}
+        {{ t(key="filter-price", lang=L) }}{% if currency_symbol %} ({{ currency_symbol }}){% endif %}
        <span class="flex items-center gap-1">
          <input type="number" name="min_price" min="0" step="0.01" inputmode="decimal"
            value="{{ min_price | default(value='') }}" placeholder="{{ price_floor }}"
--- a/assets/views/shop/show.html
+++ b/assets/views/shop/show.html
@@ -67,7 +67,7 @@
            <label for="variant-select" class="text-sm font-medium text-on-surface-strong dark:text-on-surface-dark-strong">{{ t(key="choose-option", lang=lang | default(value='sk')) }}</label>
            <select id="variant-select" x-model.number="sel" class="{{ fld }}">
              <template x-for="(v, i) in variants" :key="v.id">
-                <option :value="i" x-text="(v.label || '—') + ' · ' + v.price + ' €' + (v.in_stock ? '' : ' ({{ t(key='out-of-stock', lang=lang | default(value='sk')) }})')"></option>
+                <option :value="i" x-text="(v.label || '—') + ' · ' + v.price + ' {{ currency_symbol }}' + (v.in_stock ? '' : ' ({{ t(key='out-of-stock', lang=lang | default(value='sk')) }})')"></option>
              </template>
            </select>
          </div>
@@ -75,10 +75,10 @@

        <div class="flex items-baseline gap-3">
          <p class="text-2xl font-semibold" :class="current.on_sale ? 'text-danger' : 'text-primary dark:text-primary-dark'">
-            <span x-text="current.price"></span> €
+            <span x-text="current.price"></span> {{ currency_symbol }}
          </p>
          <template x-if="current.on_sale">
-            <p class="text-lg text-on-surface/50 line-through dark:text-on-surface-dark/50"><span x-text="current.regular_price"></span> €</p>
+            <p class="text-lg text-on-surface/50 line-through dark:text-on-surface-dark/50"><span x-text="current.regular_price"></span> {{ currency_symbol }}</p>
          </template>
        </div>

--- a/migration/src/lib.rs
+++ b/migration/src/lib.rs
@@ -48,6 +48,7 @@ mod m20260622_000006_order_search_indexes;
 mod m20260623_000001_add_short_description_to_products;
 mod m20260623_000002_strip_html_from_product_search;
 mod m20260623_000003_drop_currency;
+mod m20260623_000004_currencies;
 pub struct Migrator;

 #[async_trait::async_trait]
@@ -100,6 +101,7 @@ impl MigratorTrait for Migrator {
            Box::new(m20260623_000001_add_short_description_to_products::Migration),
            Box::new(m20260623_000002_strip_html_from_product_search::Migration),
            Box::new(m20260623_000003_drop_currency::Migration),
+            Box::new(m20260623_000004_currencies::Migration),
            // inject-above (do not remove this comment)
        ]
    }
--- a/migration/src/m20260623_000004_currencies.rs
+++ b/migration/src/m20260623_000004_currencies.rs
@@ -0,0 +1,31 @@
+use loco_rs::schema::*;
+use sea_orm_migration::prelude::*;
+
+#[derive(DeriveMigrationName)]
+pub struct Migration;
+
+#[async_trait::async_trait]
+impl MigrationTrait for Migration {
+    async fn up(&self, m: &SchemaManager) -> Result<(), DbErr> {
+        // Buyer-selectable display currencies. EUR is the base/transaction
+        // currency and is NOT stored here; each row is an alternative the buyer
+        // can switch to, whose prices are the EUR price recalculated at
+        // `rate_e4` (units of this currency per 1 EUR, scaled ×10000). For now
+        // the only row is CZK, seeded by `initializers::currency_seeder`.
+        create_table(m, "currencies",
+            &[
+            ("id", ColType::PkAuto),
+            ("code", ColType::StringUniq),
+            ("symbol", ColType::String),
+            ("rate_e4", ColType::BigIntegerWithDefault(10_000)),
+            ("enabled", ColType::BooleanWithDefault(true)),
+            ],
+            &[
+            ]
+        ).await
+    }
+
+    async fn down(&self, m: &SchemaManager) -> Result<(), DbErr> {
+        drop_table(m, "currencies").await
+    }
+}
--- a/src/app.rs
+++ b/src/app.rs
@@ -17,9 +17,9 @@ use std::{path::Path, sync::Arc};
 #[allow(unused_imports)]
 use crate::{
    controllers::{
-        account, admin_categories, admin_customers, admin_dashboard, admin_discount_profiles,
-        admin_form, admin_orders, admin_products, admin_shipping, auth, auth_pages,
-        cart, checkout, home, i18n, media, oauth2,
+        account, admin_categories, admin_currencies, admin_customers, admin_dashboard,
+        admin_discount_profiles, admin_form, admin_orders, admin_products, admin_shipping,
+        auth, auth_pages, cart, checkout, currency, home, i18n, media, oauth2,
        shop,
    },
    initializers,
@@ -83,6 +83,7 @@ impl Hooks for App {
            Box::new(initializers::view_engine::ViewEngineInitializer),
            Box::new(initializers::admin_seeder::AdminSeeder),
            Box::new(initializers::shipping_seeder::ShippingSeeder),
+            Box::new(initializers::currency_seeder::CurrencySeeder),
            Box::new(initializers::oauth2::OAuth2StoreInitializer),
            Box::new(initializers::oauth2_session::OAuth2SessionInitializer),
        ])
@@ -95,6 +96,7 @@ impl Hooks for App {
            .add_route(shop::routes())
            .add_route(cart::routes())
            .add_route(checkout::routes())
+            .add_route(currency::routes())
            // cross-cutting
            .add_route(auth::routes())
            .add_route(auth_pages::routes())
@@ -110,6 +112,7 @@ impl Hooks for App {
            .add_route(admin_orders::routes())
            .add_route(admin_customers::routes())
            .add_route(admin_shipping::routes())
+            .add_route(admin_currencies::routes())
    }

    async fn after_context(ctx: AppContext) -> Result<AppContext> {
--- a/src/controllers/admin_currencies.rs
+++ b/src/controllers/admin_currencies.rs
@@ -0,0 +1,92 @@
+//! Admin management of the alternative display currencies.
+//!
+//! EUR is the base/transaction currency and is shown read-only for context. The
+//! admin sets each alternative currency's exchange rate (units per 1 EUR) and
+//! toggles whether buyers may switch to it. The currencies themselves are fixed
+//! and seeded by `initializers::currency_seeder`.
+
+use axum_extra::extract::cookie::CookieJar;
+use loco_rs::prelude::*;
+use sea_orm::{ActiveModelTrait, EntityTrait, QueryOrder, Set};
+use serde::Deserialize;
+use serde_json::json;
+
+use crate::{
+    controllers::i18n::current_lang,
+    models::currencies,
+    shared::{
+        currency::{self, BASE_CODE, BASE_SYMBOL},
+        guard,
+    },
+};
+
+#[derive(Debug, Deserialize)]
+struct CurrencyForm {
+    rate: String,
+    enabled: Option<String>,
+}
+
+fn is_checked(value: &Option<String>) -> bool {
+    matches!(value.as_deref(), Some("on" | "true" | "1"))
+}
+
+#[debug_handler]
+async fn index(
+    auth: auth::JWT,
+    jar: CookieJar,
+    ViewEngine(v): ViewEngine<TeraView>,
+    State(ctx): State<AppContext>,
+) -> Result<Response> {
+    guard::current_admin(auth, &ctx).await?;
+    let rows = currencies::Entity::find()
+        .order_by_asc(currencies::Column::Code)
+        .all(&ctx.db)
+        .await?;
+    let currencies_json: Vec<serde_json::Value> = rows
+        .iter()
+        .map(|c| {
+            json!({
+                "id": c.id,
+                "code": c.code,
+                "symbol": c.symbol,
+                "rate": currency::format_rate(c.rate_e4),
+                "enabled": c.enabled,
+            })
+        })
+        .collect();
+    format::view(
+        &v,
+        "admin/currencies/index.html",
+        json!({
+            "base_code": BASE_CODE,
+            "base_symbol": BASE_SYMBOL,
+            "currencies": currencies_json,
+            "lang": current_lang(&jar),
+        }),
+    )
+}
+
+#[debug_handler]
+async fn update(
+    auth: auth::JWT,
+    Path(id): Path<i32>,
+    State(ctx): State<AppContext>,
+    Form(form): Form<CurrencyForm>,
+) -> Result<Response> {
+    guard::current_admin(auth, &ctx).await?;
+    let row = currencies::Entity::find_by_id(id)
+        .one(&ctx.db)
+        .await?
+        .ok_or_else(|| Error::NotFound)?;
+    let mut active = row.into_active_model();
+    active.rate_e4 = Set(currency::parse_rate(&form.rate)?);
+    active.enabled = Set(is_checked(&form.enabled));
+    active.update(&ctx.db).await?;
+    format::redirect("/admin/currencies")
+}
+
+pub fn routes() -> Routes {
+    Routes::new()
+        .add("/admin/currencies", get(index))
+        .add("/admin/currencies/{id}", post(update))
+}
--- a/src/controllers/cart.rs
+++ b/src/controllers/cart.rs
@@ -1,4 +1,4 @@
-use crate::{controllers::i18n::current_lang, shared::{guard, money::format_price, pricing}, models::{product_variants, products}};
+use crate::{controllers::i18n::current_lang, shared::{currency::{self, Currency}, guard, pricing}, models::{product_variants, products}};
 use axum::{
    http::{HeaderMap, StatusCode},
    response::Redirect,
@@ -173,7 +173,8 @@ async fn cart_response(
        return Ok((jar, Redirect::to("/cart")).into_response());
    }

-    let (lines, valid, total) = resolve_cart(ctx, &jar).await?;
+    let cur = currency::resolve(ctx, &jar).await;
+    let (lines, valid, total) = resolve_cart(ctx, &jar, &cur).await?;
    // Persist the re-validated cookie (drops now-invalid lines).
    let jar = jar.add(cart_cookie(serialize_cart(&valid)));
    let response = format::view(
@@ -181,7 +182,8 @@ async fn cart_response(
        "shop/_cart_body.html",
        json!({
            "items": lines,
-            "total": format_price(total),
+            "total": cur.format(total),
+            "currency_symbol": cur.symbol,
            "lang": current_lang(&jar),
        }),
    )?;
@@ -194,6 +196,7 @@ async fn cart_response(
 pub(crate) async fn resolve_cart(
    ctx: &AppContext,
    jar: &CookieJar,
+    cur: &Currency,
 ) -> Result<(Vec<serde_json::Value>, Vec<(i32, i32)>, i64)> {
    // Resolve the cart entries to in-stock products first, then price them all
    // for the current viewer in one batch (the price depends on who's logged in).
@@ -226,12 +229,12 @@ pub(crate) async fn resolve_cart(
            "name": product.name,
            "variant_label": variant.label,
            "slug": product.slug,
-            "price": format_price(unit_price),
-            "regular_price": format_price(priced.regular_cents),
+            "price": cur.format(unit_price),
+            "regular_price": cur.format(priced.regular_cents),
            "on_sale": priced.is_reduced(),
            "quantity": qty,
            "stock": variant.stock,
-            "line_total": format_price(line_total),
+            "line_total": cur.format(line_total),
        }));
    }

@@ -244,7 +247,8 @@ async fn show(
    ViewEngine(v): ViewEngine<TeraView>,
    State(ctx): State<AppContext>,
 ) -> Result<Response> {
-    let (lines, valid, total) = resolve_cart(&ctx, &jar).await?;
+    let cur = currency::resolve(&ctx, &jar).await;
+    let (lines, valid, total) = resolve_cart(&ctx, &jar, &cur).await?;

    // Drop any now-invalid lines from the cookie so the badge stays accurate.
    let rebuilt = serialize_cart(&valid);
@@ -254,7 +258,8 @@ async fn show(
        "shop/cart.html",
        json!({
            "items": lines,
-            "total": format_price(total),
+            "total": cur.format(total),
+            "currency_symbol": cur.symbol,
            "logged_in_admin": c.logged_in_admin,
            "logged_in_customer": c.logged_in_customer,
            "customer_name": c.customer_name,
@@ -274,14 +279,16 @@ async fn preview(
    ViewEngine(v): ViewEngine<TeraView>,
    State(ctx): State<AppContext>,
 ) -> Result<Response> {
-    let (lines, valid, total) = resolve_cart(&ctx, &jar).await?;
+    let cur = currency::resolve(&ctx, &jar).await;
+    let (lines, valid, total) = resolve_cart(&ctx, &jar, &cur).await?;
    let rebuilt = serialize_cart(&valid);
    let response = format::view(
        &v,
        "shop/_cart_preview.html",
        json!({
            "items": lines,
-            "total": format_price(total),
+            "total": cur.format(total),
+            "currency_symbol": cur.symbol,
            "lang": current_lang(&jar),
        }),
    )?;
--- a/src/controllers/checkout.rs
+++ b/src/controllers/checkout.rs
@@ -18,7 +18,7 @@ use crate::{
        users::{self, normalize_account_type},
    },
    controllers::i18n::current_lang,
-    shared::{guard, money::format_price, settings},
+    shared::{currency::Currency, guard, money::format_price, settings},
    views::checkout as view,
 };

@@ -77,7 +77,9 @@ async fn checkout_page(
    ViewEngine(v): ViewEngine<TeraView>,
    State(ctx): State<AppContext>,
 ) -> Result<Response> {
-    let (lines, _valid, subtotal) = resolve_cart(&ctx, &jar).await?;
+    // Checkout and everything past it (orders, confirmation) stay in the EUR
+    // base — the settlement currency — even when the buyer browsed in another.
+    let (lines, _valid, subtotal) = resolve_cart(&ctx, &jar, &Currency::eur()).await?;
    if lines.is_empty() {
        return format::redirect("/cart");
    }
@@ -159,7 +161,7 @@ async fn place_order(
    State(ctx): State<AppContext>,
    Form(form): Form<CheckoutForm>,
 ) -> Result<Response> {
-    let (_lines, valid, _total) = resolve_cart(&ctx, &jar).await?;
+    let (_lines, valid, _total) = resolve_cart(&ctx, &jar, &Currency::eur()).await?;
    if valid.is_empty() {
        return format::redirect("/cart");
    }
--- a/src/controllers/currency.rs
+++ b/src/controllers/currency.rs
@@ -0,0 +1,39 @@
+//! Storefront display-currency switcher.
+//!
+//! Sets the `currency` cookie to the buyer's chosen display currency, then sends
+//! them back where they were. EUR is the base; any other code must name an
+//! enabled row in `currencies` or it falls back to EUR on the next render.
+
+use axum::{
+    http::{header, HeaderMap},
+    response::Redirect,
+};
+use loco_rs::prelude::*;
+use serde::Deserialize;
+
+use crate::controllers::i18n::back_path;
+use crate::shared::currency::{BASE_CODE, COOKIE};
+
+#[derive(Debug, Deserialize)]
+pub struct CurrencyForm {
+    pub currency: String,
+}
+
+#[debug_handler]
+async fn set_currency(headers: HeaderMap, Form(form): Form<CurrencyForm>) -> Result<Response> {
+    // Store the code uppercased; validation against the enabled set happens at
+    // render time (shared::currency::resolve), which falls back to EUR.
+    let code = form.currency.trim().to_uppercase();
+    let code = if code.is_empty() { BASE_CODE.to_string() } else { code };
+    let cookie = format!("{COOKIE}={code}; Path=/; Max-Age=31536000; SameSite=Lax");
+
+    Ok((
+        [(header::SET_COOKIE, cookie)],
+        Redirect::to(&back_path(&headers)),
+    )
+        .into_response())
+}
+
+pub fn routes() -> Routes {
+    Routes::new().add("/currency", post(set_currency))
+}
--- a/src/controllers/home.rs
+++ b/src/controllers/home.rs
@@ -4,7 +4,9 @@ use axum_extra::extract::cookie::CookieJar;
 use loco_rs::prelude::*;
 use serde_json::json;

-use crate::{controllers::i18n::current_lang, shared::guard, controllers::shop};
+use crate::{
+    controllers::i18n::current_lang, controllers::shop, shared::currency, shared::guard,
+};

 #[debug_handler]
 async fn index(
@@ -13,7 +15,8 @@ async fn index(
    State(ctx): State<AppContext>,
 ) -> Result<Response> {
    let user = guard::current_user(&ctx, &jar).await;
-    let products = shop::featured_products(&ctx, user.as_ref(), 8).await?;
+    let cur = currency::resolve(&ctx, &jar).await;
+    let products = shop::featured_products(&ctx, user.as_ref(), 8, &cur).await?;
    let c = guard::chrome_from(&ctx, user.as_ref());

    format::view(
@@ -25,6 +28,7 @@ async fn index(
            "logged_in_customer": c.logged_in_customer,
            "customer_name": c.customer_name,
            "customer_account_type": c.customer_account_type,
+            "currency_symbol": cur.symbol,
            "lang": current_lang(&jar),
        }),
    )
--- a/src/controllers/i18n.rs
+++ b/src/controllers/i18n.rs
@@ -34,7 +34,7 @@ async fn set_lang(headers: HeaderMap, Form(form): Form<LangForm>) -> Result<Resp
        .into_response())
 }

-fn back_path(headers: &HeaderMap) -> String {
+pub(crate) fn back_path(headers: &HeaderMap) -> String {
    let raw = headers
        .get(header::REFERER)
        .and_then(|value| value.to_str().ok())
--- a/src/controllers/mod.rs
+++ b/src/controllers/mod.rs
@@ -3,6 +3,7 @@ pub mod auth;
 pub mod auth_pages;
 pub mod oauth2;
 pub mod admin_categories;
+pub mod admin_currencies;
 pub mod admin_customers;
 pub mod admin_dashboard;
 pub mod admin_discount_profiles;
@@ -12,6 +13,7 @@ pub mod admin_products;
 pub mod admin_shipping;
 pub mod cart;
 pub mod checkout;
+pub mod currency;
 pub mod home;
 pub mod i18n;
 pub mod media;
--- a/src/controllers/shop.rs
+++ b/src/controllers/shop.rs
@@ -13,8 +13,9 @@ use serde_json::json;
 use crate::{
    controllers::i18n::current_lang,
    shared::{
+        currency::{self, Currency},
        guard,
-        money::{format_price, parse_price_to_cents},
+        money::parse_price_to_cents,
        pricing,
    },
    models::{categories, product_images, product_variants, products, users},
@@ -90,6 +91,7 @@ async fn run_search(
    ctx: &AppContext,
    user: Option<&users::Model>,
    params: &SearchParams,
+    cur: &Currency,
 ) -> Result<serde_json::Value> {
    let q = params.q.clone().unwrap_or_default();
    let q_trim = q.trim().to_string();
@@ -136,9 +138,19 @@ async fn run_search(
    let price_floor = items.iter().map(|i| i.priced.price_cents).min().unwrap_or(0);
    let price_ceil = items.iter().map(|i| i.priced.price_cents).max().unwrap_or(0);

-    // 3. Non-category filters: price band + in-stock.
-    let min_c = params.min_price.as_deref().and_then(|s| parse_price_to_cents(s).ok());
-    let max_c = params.max_price.as_deref().and_then(|s| parse_price_to_cents(s).ok());
+    // 3. Non-category filters: price band + in-stock. The typed bounds are in
+    //    the buyer's display currency; convert them back to EUR cents to compare
+    //    against the (EUR) resolved prices.
+    let min_c = params
+        .min_price
+        .as_deref()
+        .and_then(|s| parse_price_to_cents(s).ok())
+        .map(|c| cur.to_eur_cents(c));
+    let max_c = params
+        .max_price
+        .as_deref()
+        .and_then(|s| parse_price_to_cents(s).ok())
+        .map(|c| cur.to_eur_cents(c));
    let in_stock_only = is_on(&params.in_stock);
    items.retain(|i| {
        min_c.is_none_or(|m| i.priced.price_cents >= m)
@@ -203,6 +215,7 @@ async fn run_search(
            item.count,
            image,
            cat_name,
+            cur,
        ));
    }

@@ -219,8 +232,9 @@ async fn run_search(
        "in_stock": in_stock_only,
        "min_price": params.min_price.clone().unwrap_or_default(),
        "max_price": params.max_price.clone().unwrap_or_default(),
-        "price_floor": format_price(price_floor),
-        "price_ceil": format_price(price_ceil),
+        "price_floor": cur.format(price_floor),
+        "price_ceil": cur.format(price_ceil),
+        "currency_symbol": cur.symbol,
        "total": total,
        "page": page,
        "pages": pages,
@@ -240,6 +254,7 @@ async fn product_rows(
    ctx: &AppContext,
    user: Option<&users::Model>,
    list: Vec<products::Model>,
+    cur: &Currency,
 ) -> Result<Vec<serde_json::Value>> {
    let ids: Vec<i32> = list.iter().map(|p| p.id).collect();
    let grouped = product_variants::Entity::grouped_for_products(&ctx.db, &ids).await?;
@@ -261,7 +276,7 @@ async fn product_rows(
    let mut rows = Vec::with_capacity(entries.len());
    for ((product, rep, count), priced) in entries.iter().zip(priced.iter()) {
        let image = product_images::first_for(ctx, product.id).await?;
-        rows.push(view::product_card(product, rep, priced, *count, image, None));
+        rows.push(view::product_card(product, rep, priced, *count, image, None, cur));
    }
    Ok(rows)
 }
@@ -272,6 +287,7 @@ pub(crate) async fn featured_products(
    ctx: &AppContext,
    user: Option<&users::Model>,
    limit: u64,
+    cur: &Currency,
 ) -> Result<Vec<serde_json::Value>> {
    let list = products::Entity::find()
        .filter(products::Column::Published.eq(true))
@@ -279,7 +295,7 @@ pub(crate) async fn featured_products(
        .limit(limit)
        .all(&ctx.db)
        .await?;
-    product_rows(ctx, user, list).await
+    product_rows(ctx, user, list, cur).await
 }

 /// The site-wide category sidebar, loaded lazily via htmx by the base layout so
@@ -320,7 +336,8 @@ async fn index(
    State(ctx): State<AppContext>,
 ) -> Result<Response> {
    let user = guard::current_user(&ctx, &jar).await;
-    let mut context = run_search(&ctx, user.as_ref(), &SearchParams::default()).await?;
+    let cur = currency::resolve(&ctx, &jar).await;
+    let mut context = run_search(&ctx, user.as_ref(), &SearchParams::default(), &cur).await?;
    let c = guard::chrome_from(&ctx, user.as_ref());
    add_chrome(&mut context, &c, &current_lang(&jar));
    format::view(&v, "shop/index.html", context)
@@ -341,7 +358,8 @@ async fn search(
    State(ctx): State<AppContext>,
 ) -> Result<Response> {
    let user = guard::current_user(&ctx, &jar).await;
-    let mut context = run_search(&ctx, user.as_ref(), &params).await?;
+    let cur = currency::resolve(&ctx, &jar).await;
+    let mut context = run_search(&ctx, user.as_ref(), &params, &cur).await?;
    let lang = current_lang(&jar);

    if headers.contains_key("HX-Request") {
@@ -385,12 +403,13 @@ async fn show(
    };

    let user = guard::current_user(&ctx, &jar).await;
+    let cur = currency::resolve(&ctx, &jar).await;
    let variants = product_variants::Entity::for_product(&ctx.db, product.id).await?;
    let variant_prices = pricing::price_variants(&ctx, &variants, user.as_ref()).await?;
    let options: Vec<serde_json::Value> = variants
        .iter()
        .zip(variant_prices.iter())
-        .map(|(variant, priced)| view::variant_option(variant, priced))
+        .map(|(variant, priced)| view::variant_option(variant, priced, &cur))
        .collect();
    // The card header uses the representative (first) variant for its headline
    // price; the picker below lets the customer switch.
@@ -404,6 +423,7 @@ async fn show(
            variants.len(),
            None,
            category.as_ref().map(|c| c.name.clone()),
+            &cur,
        ),
        // A product with no variants isn't purchasable; show it without a price.
        _ => serde_json::json!({
@@ -428,6 +448,7 @@ async fn show(
            "logged_in_customer": c.logged_in_customer,
            "customer_name": c.customer_name,
            "customer_account_type": c.customer_account_type,
+            "currency_symbol": cur.symbol,
            "lang": current_lang(&jar),
        }),
    )
@@ -463,7 +484,8 @@ async fn category(
    };

    let user = guard::current_user(&ctx, &jar).await;
-    let mut context = run_search(&ctx, user.as_ref(), &params).await?;
+    let cur = currency::resolve(&ctx, &jar).await;
+    let mut context = run_search(&ctx, user.as_ref(), &params, &cur).await?;
    if let Some(map) = context.as_object_mut() {
        map.insert("category".into(), serde_json::to_value(&category)?);
        map.insert("breadcrumbs".into(), serde_json::to_value(&breadcrumbs)?);
--- a/src/initializers/currency_seeder.rs
+++ b/src/initializers/currency_seeder.rs
@@ -0,0 +1,50 @@
+//! Ensures the built-in alternative display currencies always exist.
+//!
+//! EUR is the base currency and is never stored. For now the only alternative is
+//! the Czech koruna (CZK); the admin sets its exchange rate and can disable it.
+//! We insert each one only when its `code` is missing, so an admin's rate/enabled
+//! changes are never overwritten on the next boot.
+
+use async_trait::async_trait;
+use loco_rs::prelude::*;
+use sea_orm::{ActiveModelTrait, ColumnTrait, EntityTrait, PaginatorTrait, QueryFilter, Set};
+
+use crate::models::currencies;
+use crate::shared::currency::SCALE;
+
+/// `(code, symbol, default_rate_e4)` — default rate is a placeholder the admin
+/// is expected to update from the live FX rate.
+const BUILTINS: [(&str, &str, i64); 1] = [("CZK", "Kč", 25 * SCALE)];
+
+pub struct CurrencySeeder;
+
+#[async_trait]
+impl Initializer for CurrencySeeder {
+    fn name(&self) -> String {
+        "currency-seeder".to_string()
+    }
+
+    async fn before_run(&self, ctx: &AppContext) -> Result<()> {
+        for (code, symbol, rate_e4) in BUILTINS {
+            let exists = currencies::Entity::find()
+                .filter(currencies::Column::Code.eq(code))
+                .count(&ctx.db)
+                .await?
+                > 0;
+            if exists {
+                continue;
+            }
+            currencies::ActiveModel {
+                code: Set(code.to_string()),
+                symbol: Set(symbol.to_string()),
+                rate_e4: Set(rate_e4),
+                enabled: Set(true),
+                ..Default::default()
+            }
+            .insert(&ctx.db)
+            .await?;
+            tracing::info!(currency = code, "seeded display currency");
+        }
+        Ok(())
+    }
+}
--- a/src/initializers/mod.rs
+++ b/src/initializers/mod.rs
@@ -1,4 +1,5 @@
 pub mod admin_seeder;
+pub mod currency_seeder;
 pub mod oauth2;
 pub mod oauth2_session;
 pub mod shipping_seeder;
--- a/src/models/_entities/currencies.rs
+++ b/src/models/_entities/currencies.rs
@@ -0,0 +1,22 @@
+//! `SeaORM` Entity, @generated by sea-orm-codegen 1.1.19
+
+use sea_orm::entity::prelude::*;
+use serde::{Deserialize, Serialize};
+
+#[derive(Clone, Debug, PartialEq, DeriveEntityModel, Eq, Serialize, Deserialize)]
+#[sea_orm(table_name = "currencies")]
+pub struct Model {
+    pub created_at: DateTimeWithTimeZone,
+    pub updated_at: DateTimeWithTimeZone,
+    #[sea_orm(primary_key)]
+    pub id: i32,
+    #[sea_orm(unique)]
+    pub code: String,
+    pub symbol: String,
+    /// Units of this currency per 1 EUR, scaled ×10000 (e.g. 25.30 → 253000).
+    pub rate_e4: i64,
+    pub enabled: bool,
+}
+
+#[derive(Copy, Clone, Debug, EnumIter, DeriveRelation)]
+pub enum Relation {}
--- a/src/models/_entities/mod.rs
+++ b/src/models/_entities/mod.rs
@@ -8,6 +8,7 @@ pub mod account_product_resolutions;
 pub mod audience_discount_profiles;
 pub mod audit_logs;
 pub mod categories;
+pub mod currencies;
 pub mod customer_profiles;
 pub mod discount_profile_products;
 pub mod discount_profiles;
--- a/src/models/_entities/prelude.rs
+++ b/src/models/_entities/prelude.rs
@@ -6,6 +6,7 @@ pub use super::account_product_resolutions::Entity as AccountProductResolutions;
 pub use super::audience_discount_profiles::Entity as AudienceDiscountProfiles;
 pub use super::audit_logs::Entity as AuditLogs;
 pub use super::categories::Entity as Categories;
+pub use super::currencies::Entity as Currencies;
 pub use super::customer_profiles::Entity as CustomerProfiles;
 pub use super::discount_profile_products::Entity as DiscountProfileProducts;
 pub use super::discount_profiles::Entity as DiscountProfiles;
--- a/src/models/currencies.rs
+++ b/src/models/currencies.rs
@@ -0,0 +1,40 @@
+use sea_orm::entity::prelude::*;
+pub use crate::models::_entities::currencies::{ActiveModel, Column, Entity, Model};
+pub type Currencies = Entity;
+
+#[async_trait::async_trait]
+impl ActiveModelBehavior for ActiveModel {
+    async fn before_save<C>(self, _db: &C, insert: bool) -> std::result::Result<Self, DbErr>
+    where
+        C: ConnectionTrait,
+    {
+        if !insert && self.updated_at.is_unchanged() {
+            let mut this = self;
+            this.updated_at = sea_orm::ActiveValue::Set(chrono::Utc::now().into());
+            Ok(this)
+        } else {
+            Ok(self)
+        }
+    }
+}
+
+// implement your read-oriented logic here
+impl Model {}
+
+// implement your write-oriented logic here
+impl ActiveModel {}
+
+// implement your custom finders, selectors oriented logic here
+impl Entity {
+    /// An enabled currency by its ISO code (case-insensitive), or `None`.
+    pub async fn find_enabled_by_code<C: ConnectionTrait>(
+        db: &C,
+        code: &str,
+    ) -> Result<Option<Model>, DbErr> {
+        Entity::find()
+            .filter(Column::Code.eq(code.to_uppercase()))
+            .filter(Column::Enabled.eq(true))
+            .one(db)
+            .await
+    }
+}
--- a/src/models/mod.rs
+++ b/src/models/mod.rs
@@ -12,6 +12,7 @@ pub mod account_product_resolutions;
 pub mod audience_discount_profiles;
 pub mod audit_logs;
 pub mod categories;
+pub mod currencies;
 pub mod discount_profile_products;
 pub mod discount_profiles;
 pub mod customer_profiles;
--- a/src/shared/currency.rs
+++ b/src/shared/currency.rs
@@ -0,0 +1,144 @@
+//! Buyer-selectable display currency.
+//!
+//! EUR is the base/transaction currency: every price is stored and reasoned
+//! about in EUR minor units (cents). A buyer may switch their *display* currency
+//! (cookie [`COOKIE`]); non-base currencies live in the `currencies` table with
+//! an admin-set exchange `rate_e4` (units per 1 EUR, scaled ×10000). The
+//! [`Currency`] resolved per request converts EUR cents into the chosen currency
+//! for display only — the cart logic, orders and admin stay in EUR.
+
+use axum_extra::extract::cookie::CookieJar;
+use loco_rs::prelude::*;
+
+use crate::models::currencies;
+use crate::shared::money::format_price;
+
+/// Cookie holding the buyer's chosen display-currency code.
+pub const COOKIE: &str = "currency";
+/// The base/transaction currency code.
+pub const BASE_CODE: &str = "EUR";
+/// The base currency symbol.
+pub const BASE_SYMBOL: &str = "€";
+/// Fixed-point scale for exchange rates (`rate_e4` = rate × 10000).
+pub const SCALE: i64 = 10_000;
+
+/// A resolved display currency: how to label prices and how to convert them
+/// from the EUR base.
+#[derive(Debug, Clone)]
+pub struct Currency {
+    pub code: String,
+    pub symbol: String,
+    /// Units of this currency per 1 EUR, scaled ×10000. `SCALE` for the base.
+    pub rate_e4: i64,
+}
+
+impl Currency {
+    /// The base currency (EUR), the identity conversion.
+    #[must_use]
+    pub fn eur() -> Self {
+        Self {
+            code: BASE_CODE.to_string(),
+            symbol: BASE_SYMBOL.to_string(),
+            rate_e4: SCALE,
+        }
+    }
+
+    #[must_use]
+    pub fn is_base(&self) -> bool {
+        self.code == BASE_CODE
+    }
+
+    /// Convert EUR minor units into this currency's minor units (half-up).
+    #[must_use]
+    pub fn convert_cents(&self, eur_cents: i64) -> i64 {
+        if self.is_base() {
+            return eur_cents;
+        }
+        let scale = i128::from(SCALE);
+        ((i128::from(eur_cents) * i128::from(self.rate_e4) + scale / 2) / scale) as i64
+    }
+
+    /// Inverse of [`convert_cents`]: this currency's minor units back to EUR
+    /// minor units (half-up). Used to interpret price-filter bounds typed in the
+    /// display currency.
+    #[must_use]
+    pub fn to_eur_cents(&self, cents: i64) -> i64 {
+        if self.is_base() || self.rate_e4 == 0 {
+            return cents;
+        }
+        let rate = i128::from(self.rate_e4);
+        ((i128::from(cents) * i128::from(SCALE) + rate / 2) / rate) as i64
+    }
+
+    /// Render EUR minor units as a plain decimal string in this currency (no
+    /// symbol). The symbol is appended by templates via `currency_symbol`.
+    #[must_use]
+    pub fn format(&self, eur_cents: i64) -> String {
+        format_price(self.convert_cents(eur_cents))
+    }
+}
+
+/// Resolve the buyer's display currency from the `currency` cookie, falling back
+/// to EUR when the cookie is absent, names the base, or names a currency that is
+/// missing or disabled.
+pub async fn resolve(ctx: &AppContext, jar: &CookieJar) -> Currency {
+    let code = jar
+        .get(COOKIE)
+        .map(|c| c.value().to_string())
+        .unwrap_or_default();
+    if code.is_empty() || code.eq_ignore_ascii_case(BASE_CODE) {
+        return Currency::eur();
+    }
+    match currencies::Entity::find_enabled_by_code(&ctx.db, &code).await {
+        Ok(Some(m)) => Currency {
+            code: m.code,
+            symbol: m.symbol,
+            rate_e4: m.rate_e4,
+        },
+        _ => Currency::eur(),
+    }
+}
+
+/// Parse an exchange rate typed in major units ("25", "25.3", "25,30",
+/// "25.3045") into `rate_e4` (×10000). Rejects negatives and >4 decimals.
+pub fn parse_rate(value: &str) -> Result<i64> {
+    let value = value.trim().replace(',', ".");
+    let invalid = || Error::BadRequest("invalid exchange rate".to_string());
+    let (whole, frac) = match value.split_once('.') {
+        Some((w, f)) => (w, f),
+        None => (value.as_str(), ""),
+    };
+    if frac.len() > 4 || whole.is_empty() || !whole.chars().all(|c| c.is_ascii_digit()) {
+        return Err(invalid());
+    }
+    if !frac.chars().all(|c| c.is_ascii_digit()) {
+        return Err(invalid());
+    }
+    let whole: i64 = whole.parse().map_err(|_| invalid())?;
+    // Right-pad the fractional part to exactly 4 digits.
+    let padded = format!("{frac:0<4}");
+    let frac: i64 = if padded.is_empty() {
+        0
+    } else {
+        padded.parse().map_err(|_| invalid())?
+    };
+    let rate = whole * SCALE + frac;
+    if rate <= 0 {
+        return Err(invalid());
+    }
+    Ok(rate)
+}
+
+/// Render `rate_e4` as a human string, trimming trailing zeros (253000 → "25.3",
+/// 250000 → "25").
+#[must_use]
+pub fn format_rate(rate_e4: i64) -> String {
+    let whole = rate_e4 / SCALE;
+    let frac = (rate_e4 % SCALE).abs();
+    if frac == 0 {
+        return whole.to_string();
+    }
+    let frac = format!("{frac:04}");
+    let trimmed = frac.trim_end_matches('0');
+    format!("{whole}.{trimmed}")
+}
--- a/src/shared/mod.rs
+++ b/src/shared/mod.rs
@@ -1,6 +1,7 @@
 //! Cross-cutting helpers used across feature slices.

 pub mod csrf;
+pub mod currency;
 pub mod guard;
 pub mod money;
 pub mod pricing;
--- a/src/views/shop.rs
+++ b/src/views/shop.rs
@@ -3,7 +3,7 @@
 use serde_json::{json, Value};

 use crate::models::_entities::{categories, product_images, product_variants, products};
-use crate::shared::money::format_price;
+use crate::shared::currency::Currency;
 use crate::shared::pricing::PricedProduct;

 /// Card/list shape for a product: model fields plus the viewer's resolved price
@@ -20,6 +20,7 @@ pub fn product_card(
    variant_count: usize,
    image: Option<String>,
    category_name: Option<String>,
+    cur: &Currency,
 ) -> Value {
    json!({
        "id": product.id,
@@ -28,10 +29,10 @@ pub fn product_card(
        "slug": product.slug,
        "description": product.description,
        "short_description": product.short_description,
-        "price": format_price(priced.price_cents),
+        "price": cur.format(priced.price_cents),
        "on_sale": priced.is_reduced(),
        "is_business": priced.is_business,
-        "regular_price": format_price(priced.regular_cents),
+        "regular_price": cur.format(priced.regular_cents),
        "sku": representative.sku,
        "stock": representative.stock,
        "tracked": representative.tracked(),
@@ -45,7 +46,11 @@ pub fn product_card(
 }

 /// One priced variant row for the product detail page's option picker.
-pub fn variant_option(variant: &product_variants::Model, priced: &PricedProduct) -> Value {
+pub fn variant_option(
+    variant: &product_variants::Model,
+    priced: &PricedProduct,
+    cur: &Currency,
+) -> Value {
    json!({
        "id": variant.id,
        "label": variant.label,
@@ -53,9 +58,9 @@ pub fn variant_option(variant: &product_variants::Model, priced: &PricedProduct)
        "stock": variant.stock,
        "tracked": variant.tracked(),
        "in_stock": variant.in_stock(),
-        "price": format_price(priced.price_cents),
+        "price": cur.format(priced.price_cents),
        "on_sale": priced.is_reduced(),
-        "regular_price": format_price(priced.regular_cents),
+        "regular_price": cur.format(priced.regular_cents),
        "is_business": priced.is_business,
    })
 }