From a20756c0fff6429002660e94eda2e7ceb3ee991a Mon Sep 17 00:00:00 2001
From: Savely Krendelhoff <alicecandyom@proton.me>
Date: Sat, 6 Sep 2025 16:47:03 +0700
Subject: [PATCH] Add executable

---
 cmd/converter/main.go | 52 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)
 create mode 100644 cmd/converter/main.go

diff --git a/cmd/converter/main.go b/cmd/converter/main.go
new file mode 100644
index 0000000..2ea627e
--- /dev/null
+++ b/cmd/converter/main.go
@@ -0,0 +1,52 @@
+package main
+
+import (
+	"converter/app"
+	"converter/domain"
+	"converter/infrastructure/coinmarketcap"
+	"fmt"
+	"os"
+)
+
+const (
+	expectedArgs = 4 // program name + 3 arguments
+	apiKeyEnvVar = "CMC_API_KEY"
+)
+
+func main() {
+	// Check command line arguments
+	if len(os.Args) != expectedArgs {
+		fmt.Fprintf(os.Stderr, "Usage: %s <amount> <from_currency> <to_currency>\n", os.Args[0])
+		fmt.Fprintf(os.Stderr, "Example: %s 100.50 USD BTC\n", os.Args[0])
+		os.Exit(1)
+	}
+
+	// Parse arguments
+	amount := os.Args[1]
+	fromCurrency := os.Args[2]
+	toCurrency := os.Args[3]
+
+	// Get API key from environment
+	apiKey := os.Getenv(apiKeyEnvVar)
+	if apiKey == "" {
+		fmt.Fprintf(os.Stderr, "Error: %s environment variable is required\n", apiKeyEnvVar)
+		fmt.Fprintf(os.Stderr, "Please set your CoinMarketCap API key:\n")
+		fmt.Fprintf(os.Stderr, "export %s=your_api_key_here\n", apiKeyEnvVar)
+		os.Exit(1)
+	}
+
+	// Initialize dependencies
+	client := coinmarketcap.NewClient(apiKey)
+	converter := domain.NewCurrencyConverter()
+	useCase := app.NewConvertCurrencyUseCase(client, converter)
+
+	// Execute conversion
+	result, err := useCase.Execute(amount, fromCurrency, toCurrency)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error: %v\n", err)
+		os.Exit(1)
+	}
+
+	// Output result
+	fmt.Printf("%s %s\n", result.Amount.StringFixed(8), result.Currency.Code)
+}
\ No newline at end of file