refactor: restructure project

internal/downloader/downloader.go

@@ -0,0 +1,87 @@
+package downloader
+
+import (
+	"errors"
+	"io"
+	"net/http"
+	"os"
+	"strings"
+
+	req "github.com/levigross/grequests"
+	"github.com/schollz/progressbar/v3"
+)
+
+var (
+	ErrAccessDenied     = errors.New("restricted access (credentials required)")
+	ErrInvalidURL       = errors.New("invalid url")
+	ErrUnknownAuthority = errors.New("certificate from unknown authority")
+)
+
+type Context struct {
+	Filename string
+	Link     string
+}
+
+func NewContext(filename, link string) *Context {
+	return &Context{
+		Filename: filename,
+		Link:     link,
+	}
+}
+
+func (c *Context) Download() error {
+	resp, err := req.Head(c.Link, nil)
+	if err != nil {
+		if strings.Contains(err.Error(), "no such host") {
+			return ErrInvalidURL
+		}
+		if strings.Contains(err.Error(), "certificate signed by unknown authority") {
+			return ErrUnknownAuthority
+		}
+		return err
+	}
+	defer resp.Close()
+	if resp.StatusCode == http.StatusNotFound {
+		return ErrInvalidURL
+	}
+	if resp.StatusCode == http.StatusUnauthorized {
+		return ErrAccessDenied
+	}
+	if resp.StatusCode != http.StatusOK {
+		return errors.New(resp.RawResponse.Status)
+	}
+	resp.Close()
+
+	resp, err = req.Get(c.Link, nil)
+	if err != nil {
+		return err
+	}
+
+	var filesize int64
+	if resp.RawResponse.ContentLength > -1 {
+		filesize = resp.RawResponse.ContentLength
+	}
+
+	destFile, err := os.OpenFile(c.Filename, os.O_CREATE|os.O_WRONLY, 0644)
+	if err != nil {
+		return err
+	}
+	defer destFile.Close()
+
+	bar := progressbar.DefaultBytes(
+		filesize,
+		"downloading",
+	)
+
+	_, err = io.Copy(io.MultiWriter(destFile, bar), resp.RawResponse.Body)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (c *Context) FileExists() bool {
+	_, err := os.Stat(c.Filename)
+	return !errors.Is(err, os.ErrNotExist)
+}

internal/downloader/downloader_test.go

@@ -0,0 +1,118 @@
+package downloader_test
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"testing"
+
+	"git.ar21.de/yolokube/country-geo-locations/internal/downloader"
+)
+
+// TestNewContext tests the creation of a new Context.
+func TestNewContext(t *testing.T) {
+	filename := "testfile"
+	link := "http://example.com"
+	ctx := downloader.NewContext(filename, link)
+
+	if ctx.Filename != filename {
+		t.Errorf("expected %s, got %s", filename, ctx.Filename)
+	}
+	if ctx.Link != link {
+		t.Errorf("expected %s, got %s", link, ctx.Link)
+	}
+}
+
+// TestDownload tests the Download function with different scenarios.
+func TestDownload(t *testing.T) {
+	t.Run("ValidDownload", func(t *testing.T) {
+		// Mock server to simulate a valid download
+		server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+			w.WriteHeader(http.StatusOK)
+			w.Write([]byte("This is the file content"))
+		}))
+		defer server.Close()
+
+		filename := "test_valid_download.txt"
+		ctx := downloader.NewContext(filename, server.URL)
+		defer os.Remove(filename)
+
+		err := ctx.Download()
+		if err != nil {
+			t.Errorf("expected no error, got %v", err)
+		}
+
+		if !ctx.FileExists() {
+			t.Errorf("expected file to exist, but it does not")
+		}
+	})
+
+	t.Run("InvalidURL", func(t *testing.T) {
+		ctx := downloader.NewContext("test_invalid_url.txt", "http://invalid.url")
+		err := ctx.Download()
+
+		if err == nil || err.Error() != "invalid url" {
+			t.Errorf("expected invalid url error, got %v", err)
+		}
+	})
+
+	t.Run("CertificateError", func(t *testing.T) {
+		// This test assumes a self-signed certificate or similar issue. This is hard to simulate in a unit test.
+		ctx := downloader.NewContext("test_cert_error.txt", "https://self-signed.badssl.com/") // Example URL that can be used
+
+		if err := ctx.Download(); err == nil || err.Error() != "certificate from unknown authority" {
+			t.Errorf("expected certificate from unknown authority error, got %v", err)
+		}
+	})
+
+	t.Run("FileNotFound", func(t *testing.T) {
+		// Mock server to simulate a 404 response
+		server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+			w.WriteHeader(http.StatusNotFound)
+		}))
+		defer server.Close()
+
+		ctx := downloader.NewContext("test_not_found.txt", server.URL)
+
+		if err := ctx.Download(); err == nil || err.Error() != "invalid url" {
+			t.Errorf("expected invalid url error, got %v", err)
+		}
+	})
+
+	t.Run("RestrictedAccess", func(t *testing.T) {
+		// Mock server to simulate a 401 response
+		server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+			w.WriteHeader(http.StatusUnauthorized)
+		}))
+		defer server.Close()
+
+		ctx := downloader.NewContext("test_restricted_access.txt", server.URL)
+
+		if err := ctx.Download(); err == nil || err.Error() != "restricted access (credentials required)" {
+			t.Errorf("expected restricted access error, got %v", err)
+		}
+	})
+}
+
+// TestFileExists tests the FileExists function.
+func TestFileExists(t *testing.T) {
+	filename := "testfile_exists.txt"
+	ctx := downloader.NewContext(filename, "http://example.com")
+
+	// Ensure file does not exist initially
+	if ctx.FileExists() {
+		t.Errorf("expected file to not exist, but it does")
+	}
+
+	// Create a file and check again
+	file, err := os.Create(filename)
+	if err != nil {
+		t.Fatalf("failed to create test file: %v", err)
+	}
+	file.Close()
+	defer os.Remove(filename)
+
+	if !ctx.FileExists() {
+		t.Errorf("expected file to exist, but it does not")
+	}
+}