refactor: migrate to eslint flat config and format codebase with prettier

- Remove legacy .eslintrc.cjs and .eslintignore
- Add eslint.config.js with flat config, security rules (no-eval, no-implied-eval, no-new-func, no-script-url)
- Add .prettierrc and .prettierignore
- Format entire codebase with prettier

src/api/currency.ts

@@ -1,46 +1,46 @@
 // Currency exchange rate API
 // Uses free exchangerate.host API
 
-import axios from 'axios'
+import axios from 'axios';
 
 interface ExchangeRates {
-  USD: number
-  CNY: number
-  IRR: number
+  USD: number;
+  CNY: number;
+  IRR: number;
 }
 
 interface CachedRates {
-  rates: ExchangeRates
-  timestamp: number
+  rates: ExchangeRates;
+  timestamp: number;
 }
 
-const CACHE_DURATION = 60 * 60 * 1000 // 1 hour in milliseconds
+const CACHE_DURATION = 60 * 60 * 1000; // 1 hour in milliseconds
 
 // Fallback rates if API fails (approximate)
 const FALLBACK_RATES: ExchangeRates = {
-  USD: 100,      // 1 USD = 100 RUB
-  CNY: 14,       // 1 CNY = 14 RUB
-  IRR: 0.0024,   // 1 IRR = 0.0024 RUB (or 1 RUB = ~420 IRR)
-}
+  USD: 100, // 1 USD = 100 RUB
+  CNY: 14, // 1 CNY = 14 RUB
+  IRR: 0.0024, // 1 IRR = 0.0024 RUB (or 1 RUB = ~420 IRR)
+};
 
-let cachedRates: CachedRates | null = null
+let cachedRates: CachedRates | null = null;
 
 export const currencyApi = {
   // Get all exchange rates (RUB to other currencies)
   getExchangeRates: async (): Promise<ExchangeRates> => {
     // Check cache first
     if (cachedRates && Date.now() - cachedRates.timestamp < CACHE_DURATION) {
-      return cachedRates.rates
+      return cachedRates.rates;
     }
 
     try {
       // Try primary API (exchangerate.host) - get RUB based rates
       const response = await axios.get<{
-        success?: boolean
-        rates?: { USD?: number; CNY?: number; IRR?: number }
+        success?: boolean;
+        rates?: { USD?: number; CNY?: number; IRR?: number };
       }>('https://api.exchangerate.host/latest', {
         params: { base: 'RUB', symbols: 'USD,CNY,IRR' },
-      })
+      });
 
       if (response.data.success && response.data.rates) {
         // API returns how much of each currency equals 1 RUB
@@ -49,51 +49,65 @@ export const currencyApi = {
           USD: response.data.rates.USD ? 1 / response.data.rates.USD : FALLBACK_RATES.USD,
           CNY: response.data.rates.CNY ? 1 / response.data.rates.CNY : FALLBACK_RATES.CNY,
           IRR: response.data.rates.IRR ? 1 / response.data.rates.IRR : FALLBACK_RATES.IRR,
-        }
-        cachedRates = { rates, timestamp: Date.now() }
-        return rates
+        };
+        cachedRates = { rates, timestamp: Date.now() };
+        return rates;
       }
 
       // Try backup API (open.er-api.com)
       const backupResponse = await axios.get<{
-        rates?: { USD?: number; CNY?: number; IRR?: number }
-      }>('https://open.er-api.com/v6/latest/RUB')
+        rates?: { USD?: number; CNY?: number; IRR?: number };
+      }>('https://open.er-api.com/v6/latest/RUB');
 
       if (backupResponse.data.rates) {
         const rates: ExchangeRates = {
-          USD: backupResponse.data.rates.USD ? 1 / backupResponse.data.rates.USD : FALLBACK_RATES.USD,
-          CNY: backupResponse.data.rates.CNY ? 1 / backupResponse.data.rates.CNY : FALLBACK_RATES.CNY,
-          IRR: backupResponse.data.rates.IRR ? 1 / backupResponse.data.rates.IRR : FALLBACK_RATES.IRR,
-        }
-        cachedRates = { rates, timestamp: Date.now() }
-        return rates
+          USD: backupResponse.data.rates.USD
+            ? 1 / backupResponse.data.rates.USD
+            : FALLBACK_RATES.USD,
+          CNY: backupResponse.data.rates.CNY
+            ? 1 / backupResponse.data.rates.CNY
+            : FALLBACK_RATES.CNY,
+          IRR: backupResponse.data.rates.IRR
+            ? 1 / backupResponse.data.rates.IRR
+            : FALLBACK_RATES.IRR,
+        };
+        cachedRates = { rates, timestamp: Date.now() };
+        return rates;
       }
 
       // Return fallback rates if both APIs fail
-      return FALLBACK_RATES
+      return FALLBACK_RATES;
     } catch (error) {
-      console.warn('Failed to fetch exchange rates, using fallback:', error)
-      return FALLBACK_RATES
+      console.warn('Failed to fetch exchange rates, using fallback:', error);
+      return FALLBACK_RATES;
     }
   },
 
   // Convert RUB to target currency
-  convertFromRub: (rubAmount: number, targetCurrency: keyof ExchangeRates, rates: ExchangeRates): number => {
-    const rate = rates[targetCurrency]
+  convertFromRub: (
+    rubAmount: number,
+    targetCurrency: keyof ExchangeRates,
+    rates: ExchangeRates,
+  ): number => {
+    const rate = rates[targetCurrency];
     if (!rate || rate <= 0) {
-      return rubAmount / FALLBACK_RATES[targetCurrency]
+      return rubAmount / FALLBACK_RATES[targetCurrency];
     }
-    return rubAmount / rate
+    return rubAmount / rate;
   },
 
   // Convert from target currency to RUB
-  convertToRub: (amount: number, sourceCurrency: keyof ExchangeRates, rates: ExchangeRates): number => {
-    const rate = rates[sourceCurrency]
+  convertToRub: (
+    amount: number,
+    sourceCurrency: keyof ExchangeRates,
+    rates: ExchangeRates,
+  ): number => {
+    const rate = rates[sourceCurrency];
     if (!rate || rate <= 0) {
-      return amount * FALLBACK_RATES[sourceCurrency]
+      return amount * FALLBACK_RATES[sourceCurrency];
     }
-    return amount * rate
+    return amount * rate;
   },
-}
+};
 
-export type { ExchangeRates }
+export type { ExchangeRates };