feat(api): wire server configuration and dependencies

backend/cmd/api/config.go

@@ -0,0 +1,68 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"strings"
+	"time"
+)
+
+type config struct {
+	ServerAddr       string
+	FrontendOrigin   string
+	ZarinHubEndpoint string
+	ZarinHubToken    string
+	ZarinHubTimeout  time.Duration
+	DatabasePath     string
+}
+
+func loadConfig() (config, error) {
+	return readConfig(os.Getenv)
+}
+
+func readConfig(getenv func(string) string) (config, error) {
+	token := strings.TrimSpace(getenv("ZARINHUB_ACCESS_TOKEN"))
+	if token == "" {
+		return config{}, fmt.Errorf("ZARINHUB_ACCESS_TOKEN is required")
+	}
+
+	timeoutText := valueOrDefault(
+		getenv("ZARINHUB_TIMEOUT"),
+		"5s",
+	)
+	timeout, err := time.ParseDuration(timeoutText)
+	if err != nil || timeout <= 0 {
+		return config{}, fmt.Errorf(
+			"ZARINHUB_TIMEOUT must be a positive duration",
+		)
+	}
+
+	return config{
+		ServerAddr: valueOrDefault(
+			getenv("SERVER_ADDR"),
+			"127.0.0.1:8080",
+		),
+		FrontendOrigin: valueOrDefault(
+			getenv("FRONTEND_ORIGIN"),
+			"http://127.0.0.1:3000",
+		),
+		ZarinHubEndpoint: valueOrDefault(
+			getenv("ZARINHUB_ENDPOINT"),
+			"https://zarin-hub.com/api/v5/KYC/CardToIban",
+		),
+		ZarinHubToken:   token,
+		ZarinHubTimeout: timeout,
+		DatabasePath: valueOrDefault(
+			getenv("DATABASE_PATH"),
+			"./card-to-iban.db",
+		),
+	}, nil
+}
+
+func valueOrDefault(value string, fallback string) string {
+	if strings.TrimSpace(value) == "" {
+		return fallback
+	}
+
+	return strings.TrimSpace(value)
+}

backend/cmd/api/config_test.go

@@ -0,0 +1,54 @@
+package main
+
+import (
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestReadConfigUsesDefaults(t *testing.T) {
+	values := map[string]string{
+		"ZARINHUB_ACCESS_TOKEN": "test-token",
+	}
+
+	config, err := readConfig(func(key string) string {
+		return values[key]
+	})
+	if err != nil {
+		t.Fatalf("readConfig() error = %v", err)
+	}
+
+	if config.ServerAddr != "127.0.0.1:8080" {
+		t.Errorf("ServerAddr = %q", config.ServerAddr)
+	}
+	if config.FrontendOrigin != "http://127.0.0.1:3000" {
+		t.Errorf("FrontendOrigin = %q", config.FrontendOrigin)
+	}
+	if config.ZarinHubTimeout != 5*time.Second {
+		t.Errorf("ZarinHubTimeout = %v", config.ZarinHubTimeout)
+	}
+	if config.DatabasePath != "./card-to-iban.db" {
+		t.Errorf("DatabasePath = %q", config.DatabasePath)
+	}
+}
+
+func TestReadConfigRejectsMissingAccessToken(t *testing.T) {
+	_, err := readConfig(func(key string) string { return "" })
+	if err == nil || !strings.Contains(err.Error(), "ZARINHUB_ACCESS_TOKEN") {
+		t.Fatalf("readConfig() error = %v, want missing token error", err)
+	}
+}
+
+func TestReadConfigRejectsInvalidTimeout(t *testing.T) {
+	values := map[string]string{
+		"ZARINHUB_ACCESS_TOKEN": "test-token",
+		"ZARINHUB_TIMEOUT":      "later",
+	}
+
+	_, err := readConfig(func(key string) string {
+		return values[key]
+	})
+	if err == nil || !strings.Contains(err.Error(), "ZARINHUB_TIMEOUT") {
+		t.Fatalf("readConfig() error = %v, want timeout error", err)
+	}
+}

backend/cmd/api/main.go

@@ -1,18 +1,103 @@
 package main
 
 import (
+	"context"
 	"encoding/json"
-	"log"
+	"errors"
+	"fmt"
+	"log/slog"
 	"net/http"
+	"os"
+	"time"
+
+	"card-to-iban/internal/httpapi"
+	"card-to-iban/internal/repository"
+	"card-to-iban/internal/service"
+	"card-to-iban/internal/storage"
+	"card-to-iban/internal/zarinhub"
+
+	"github.com/joho/godotenv"
 )
 
 func main() {
-	http.HandleFunc("/health", healthHandler)
+	logger := slog.New(
+		slog.NewJSONHandler(os.Stdout, nil),
+	)
 
-	log.Println("server listening on http://localhost:8080")
+	if err := run(logger); err != nil {
+		logger.Error("server stopped", "error", err)
+		os.Exit(1)
+	}
+}
 
-	if err := http.ListenAndServe(":8080", nil); err != nil {
-		log.Fatal(err)
+func run(logger *slog.Logger) error {
+	loadLocalEnvironment()
+
+	config, err := loadConfig()
+	if err != nil {
+		return fmt.Errorf("load configuration: %w", err)
+	}
+
+	db, err := storage.OpenSQLite(config.DatabasePath)
+	if err != nil {
+		return err
+	}
+
+	migrationContext, cancelMigration := context.WithTimeout(
+		context.Background(),
+		5*time.Second,
+	)
+	defer cancelMigration()
+
+	if err := storage.Migrate(migrationContext, db); err != nil {
+		if closeErr := db.Close(); closeErr != nil {
+			return errors.Join(err, closeErr)
+		}
+
+		return err
+	}
+
+	zarinHubClient := zarinhub.NewClient(
+		&http.Client{Timeout: config.ZarinHubTimeout},
+		config.ZarinHubEndpoint,
+		config.ZarinHubToken,
+	)
+	cardService := service.NewCardService(zarinHubClient)
+	auditRepository := repository.NewAuditRepository(db)
+	handler := httpapi.NewHandler(
+		cardService,
+		auditRepository,
+		logger,
+	)
+
+	mux := http.NewServeMux()
+	mux.HandleFunc("/health", healthHandler)
+	mux.HandleFunc("/api/v1/card-to-iban", handler.Convert)
+
+	server := &http.Server{
+		Addr: config.ServerAddr,
+		Handler: httpapi.AllowOrigin(
+			config.FrontendOrigin,
+			mux,
+		),
+		ReadHeaderTimeout: 5 * time.Second,
+		ReadTimeout:       10 * time.Second,
+		WriteTimeout:      15 * time.Second,
+		IdleTimeout:       60 * time.Second,
+	}
+
+	logger.Info("server listening", "address", config.ServerAddr)
+	serverErr := server.ListenAndServe()
+	closeErr := db.Close()
+
+	return errors.Join(serverErr, closeErr)
+}
+
+func loadLocalEnvironment() {
+	for _, path := range []string{".env", "../.env"} {
+		if err := godotenv.Load(path); err == nil {
+			return
+		}
 	}
 }
 
@@ -29,6 +114,10 @@ func healthHandler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	if err := json.NewEncoder(w).Encode(response); err != nil {
-		log.Println("failed to encode health response:", err)
+		slog.ErrorContext(
+			r.Context(),
+			"health response encoding failed",
+			"error", err,
+		)
 	}
 }

backend/go.mod

@@ -2,7 +2,10 @@ module card-to-iban
 
 go 1.27.1
 
-require modernc.org/sqlite v1.59.0
+require (
+	github.com/joho/godotenv v1.5.1
+	modernc.org/sqlite v1.59.0
+)
 
 require (
 	github.com/dustin/go-humanize v1.0.1 // indirect

backend/go.sum

@@ -6,6 +6,8 @@ github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/hashicorp/golang-lru/v2 v2.0.7 h1:a+bsQ5rvGLjzHuww6tVxozPZFVghXaHOwFs4luLUK2k=
 github.com/hashicorp/golang-lru/v2 v2.0.7/go.mod h1:QeFd9opnmA6QUJc5vARoKUSoFhyfM2/ZepoAG6RGpeM=
+github.com/joho/godotenv v1.5.1 h1:7eLL/+HRGLY0ldzfGMeQkb7vMd0as4CfYvUVzLqw0N0=
+github.com/joho/godotenv v1.5.1/go.mod h1:f4LDr5Voq0i2e/R5DDNOoa2zzDfwtkZa6DnEwAbqwq4=
 github.com/mattn/go-isatty v0.0.24 h1:tGZZoVgT/KiqK1c8ocVLeDS8BSWMRd47J3Lbz7vsReI=
 github.com/mattn/go-isatty v0.0.24/go.mod h1:nMCL3Zebbrt45jsMDgnfIwz6ydEQApk5oEI3HqDio6A=
 github.com/ncruces/go-strftime v1.0.0 h1:HMFp8mLCTPp341M/ZnA4qaf7ZlsbTc+miZjCLOFAw7w=