Divide functions with cmd and core (#14)

.gitignore

@@ -20,7 +20,8 @@
 # Go workspace file
 go.work
 
-# Binary
-nix-headbump
+# Binary when not used goreleaser
+/nix-headbump
 
+# goreleaser generates to
 dist/

.goreleaser.yaml

@@ -9,6 +9,7 @@ before:
 builds:
   - env:
       - CGO_ENABLED=0
+    main: ./cmd/nix-headbump
     goos:
       - linux
       # - windows

cmd/nix-headbump/main.go

@@ -0,0 +1,92 @@
+package main
+
+import (
+	"errors"
+	"flag"
+	"fmt"
+	"log"
+	"os"
+
+	nhb "nix-headbump"
+)
+
+var (
+	version = "dev"
+	commit  = "none"
+	date    = "unknown"
+)
+
+func main() {
+	usageError := errors.New("expected 'bump' or 'detect' subcommands")
+
+	detectCmd := flag.NewFlagSet("detect", flag.ExitOnError)
+	bumpCmd := flag.NewFlagSet("bump", flag.ExitOnError)
+	versionFlag := flag.Bool("version", false, "print the version of this program")
+	currentFlag := detectCmd.Bool("current", false, "print current nixpath without bumping")
+	lastFlag := detectCmd.Bool("last", false, "print git head ref without bumping")
+	target := detectCmd.Bool("target", false, "print which file will be bumped")
+	flag.Parse()
+	if *versionFlag {
+		revision := commit[:7]
+		fmt.Printf("%s\n", "nix-headbump"+" "+version+" "+"("+revision+") # "+date)
+		return
+	}
+
+	if len(os.Args) < 2 {
+		fmt.Println(usageError.Error())
+		os.Exit(1)
+	}
+
+	path, err := nhb.GetTargetPath()
+	if err != nil {
+		log.Fatalf("Failed to get target files: %s", err.Error())
+	}
+	if path == "" {
+		log.Fatalln("Both default.nix and shell.nix are not found")
+	}
+
+	switch os.Args[1] {
+	case "detect":
+		err := detectCmd.Parse(os.Args[2:])
+		if err != nil {
+			fmt.Println(usageError.Error())
+		}
+		if *target {
+			fmt.Println(path)
+			return
+		}
+		if *currentFlag {
+			current, err := nhb.GetCurrentVersion(path)
+			if err != nil {
+				log.Fatalf("Getting the current version has been failed: %s", err.Error())
+			}
+			fmt.Println(current)
+			return
+		}
+		last, err := nhb.GetLastVersion()
+		if err != nil {
+			log.Fatalf("Getting the last version has been failed: %s", err.Error())
+		}
+		if *lastFlag {
+			fmt.Println(last)
+			return
+		}
+
+		detectCmd.PrintDefaults()
+	case "bump":
+		err := bumpCmd.Parse(os.Args[2:])
+		if err != nil {
+			fmt.Println(usageError.Error())
+		}
+		last, err := nhb.GetLastVersion()
+		if err != nil {
+			log.Fatalf("Getting the last version has been failed: %s", err.Error())
+		}
+		if err = nhb.Bump(path, last); err != nil {
+			log.Fatalf("Bumping the version has been failed: %s", err.Error())
+		}
+	default:
+		fmt.Println(usageError.Error())
+		os.Exit(1)
+	}
+}

core.go

@@ -0,0 +1,84 @@
+package core
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"regexp"
+)
+
+var (
+	re = regexp.MustCompile(`(?s)(import\s+\(fetchTarball\s+"https://github.com/NixOS/nixpkgs/archive/)([^"]+?)(\.tar\.gz"\))`)
+)
+
+func Bump(path string, last string) error {
+	origin, err := os.ReadFile(path)
+	if err != nil {
+		return err
+	}
+	replaced := re.ReplaceAll(origin, []byte("${1}"+last+"${3}"))
+	if bytes.Equal(origin, replaced) {
+		return nil
+	}
+
+	return os.WriteFile(path, replaced, os.ModePerm)
+}
+
+func GetTargetPath() (string, error) {
+	paths := [2]string{"default.nix", "shell.nix"}
+	for _, path := range paths {
+		_, err := os.Stat(path)
+		if err == nil {
+			return path, nil
+		}
+
+		if !os.IsNotExist(err) {
+			return "", fmt.Errorf("Can not open %s: %w", path, err)
+		}
+	}
+	return "", fmt.Errorf("%v are not found", paths)
+}
+
+func GetCurrentVersion(path string) (string, error) {
+	origin, err := os.ReadFile(path)
+	if err != nil {
+		return "", err
+	}
+	matches := re.FindStringSubmatch(string(origin))
+	return matches[2], nil
+}
+
+func GetLastVersion() (string, error) {
+	type commit struct {
+		Sha string `json:"sha"`
+	}
+
+	type response struct {
+		Commit commit `json:"commit"`
+	}
+
+	// https://docs.github.com/en/rest/branches/branches?apiVersion=2022-11-28#get-a-branch
+	req, _ := http.NewRequest("GET", "https://api.github.com/repos/NixOS/nixpkgs/branches/master", nil)
+	// May be necessary to set "Authorization" header if frequent requests are needed.
+	// -H "Authorization: Bearer <YOUR-TOKEN>"\
+	req.Header.Set("Accept", "application/vnd.github+json")
+	req.Header.Set("X-GitHub-Api-Version", "2022-11-28")
+	client := new(http.Client)
+	res, err := client.Do(req)
+	if err != nil {
+		return "", err
+	}
+	defer res.Body.Close()
+	body, err := io.ReadAll(res.Body)
+	if err != nil {
+		return "", err
+	}
+	jsonRes := &response{}
+	if json.Unmarshal(body, jsonRes) != nil {
+		return "", err
+	}
+	return jsonRes.Commit.Sha, nil
+}

nix-headbump_test.go → core_test.go

@@ -1,9 +1,9 @@
-package main
+package core
 
 import "testing"
 
 func TestGetCurrentVersion(t *testing.T) {
-	got, err := getCurrentVersion("default.nix")
+	got, err := GetCurrentVersion("default.nix")
 	if err != nil {
 		t.Fatalf("Getting the version has been failed: %s", err.Error())
 	}
@@ -16,7 +16,7 @@ func TestGetCurrentVersion(t *testing.T) {
 
 // Calling actual GitHub API, May be necessary to stub or disabling in CI
 func TestGetLastVersion(t *testing.T) {
-	got, err := getLastVersion()
+	got, err := GetLastVersion()
 	if err != nil {
 		t.Fatalf("Getting the last version has been failed: %s", err.Error())
 	}
@@ -28,7 +28,7 @@ func TestGetLastVersion(t *testing.T) {
 }
 
 func TestTargetPath(t *testing.T) {
-	got, err := getTargetPath()
+	got, err := GetTargetPath()
 	if err != nil {
 		t.Fatalf("Failed to get target files: %s", err.Error())
 	}