feat(cache): implement cache for cuit info

cache/cache.go

@@ -0,0 +1,41 @@
+package cache
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"time"
+
+	"github.com/gabdlr/api-cuit-go/utils"
+)
+
+const cacheDir = "./.cache"
+
+func cacheIsOld(fPath string) bool {
+	fInfo, _ := os.Stat(fPath)
+	fCreationDate := fInfo.ModTime()
+	oneYearAgo := (time.Now()).AddDate(-1, 0, 0)
+	isOld := fCreationDate.Before(oneYearAgo)
+	if isOld {
+		os.Remove(fPath)
+	}
+	return isOld
+}
+
+func Search(cuit string) ([]byte, error) {
+	cuit = utils.StandardizeCuit(cuit)
+	fPath := fmt.Sprintf("%s/%s.json", cacheDir, cuit)
+	f, err := os.ReadFile(fPath)
+	if err == nil {
+		if cacheIsOld(fPath) {
+			return []byte{0}, errors.New("cached file expired")
+		}
+		return f, nil
+	}
+	return []byte{0}, err
+}
+
+func Save(cuit string, cuitInfo []byte) {
+	cuit = utils.StandardizeCuit(cuit)
+	os.WriteFile(fmt.Sprintf("%s/%s.json", cacheDir, cuit), cuitInfo, 0644)
+}