Added format detector

CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+* [PR-11](https://github.com/rimi-itk/gh-itkdev/pull/11)
+  Added format detector
 * [PR-9](https://github.com/rimi-itk/gh-itkdev/pull/9)
   Added alternative base branches
 * [PR-7](https://github.com/rimi-itk/gh-itkdev/pull/7)

changelog/format_detector.go

@@ -0,0 +1,57 @@
+package changelog
+
+import (
+	"fmt"
+	"os"
+	"regexp"
+)
+
+func DetectPullRequestEntryFormat(changelog string) (string, error) {
+	if _, err := os.Stat(changelog); err == nil {
+		b, err := os.ReadFile(changelog)
+		if err != nil {
+			return "", fmt.Errorf("cannot read file %s", changelog)
+		}
+		changelog = string(b)
+	}
+
+	templates := getPullRequestEntryTemplates()
+
+	for _, template := range templates {
+		if template.pattern.MatchString(changelog) {
+			return template.template, nil
+		}
+	}
+
+	return templates[len(templates)-1].template, nil
+}
+
+func getPullRequestEntryTemplates() []struct {
+	pattern  *regexp.Regexp
+	template string
+} {
+	return []struct {
+		pattern  *regexp.Regexp
+		template string
+	}{
+		{
+			regexp.MustCompile("(?m)^- \\[PR-[0-9]+\\]\\([^)]+\\)\n  .+$"),
+			`- [PR-{{ .Number }}]({{ .Url }})
+  {{ .Title }}`,
+		},
+
+		{
+			regexp.MustCompile("(?m)^- \\[#[0-9]+\\]\\([^)]+\\)\n  .+$"),
+			`- [#{{ .Number }}]({{ .Url }})
+  {{ .Title }}`,
+		},
+
+		// The default – must come last.
+		{
+			// Match any non-empty changelog and provide a default template.
+			regexp.MustCompile("."),
+			`* [PR-{{ .Number }}]({{ .Url }})
+  {{ .Title }}`,
+		},
+	}
+}

changelog/format_detector_test.go

@@ -0,0 +1,44 @@
+package changelog
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestPullRequestTemplateDetector(t *testing.T) {
+	testCases := []struct {
+		changelog string
+		expected  string
+	}{
+		{
+			`- [PR-87](https://example.com/pr/87)
+  Test
+`,
+			`- [PR-{{ .Number }}]({{ .Url }})
+  {{ .Title }}`,
+		},
+
+		{
+			`- [#87](https://example.com/pr/87)
+  Test
+`,
+			`- [#{{ .Number }}]({{ .Url }})
+  {{ .Title }}`,
+		},
+
+		{
+			`* [PR-87](https://example.com/pr/87)
+  Test
+`,
+			`* [PR-{{ .Number }}]({{ .Url }})
+  {{ .Title }}`,
+		},
+	}
+
+	for _, testCase := range testCases {
+		actual, _ := DetectPullRequestEntryFormat(testCase.changelog)
+
+		assert.Equal(t, testCase.expected, actual)
+	}
+}

cmd/changelog.go

@@ -2,18 +2,22 @@ package cmd
 
 import (
 	"fmt"
+	"os/exec"
+
 	"github.com/rimi-itk/gh-itkdev/changelog"
 	"github.com/spf13/cobra"
-	"os/exec"
 )
 
 // changelogCmd represents the changelog command
 var (
 	create bool
 
 	fuckingChangelog        bool
-	pullRequestItemTemplate string = `* [PR-{{ .Number }}]({{ .Url }})
-  {{ .Title }}`
+	pullRequestItemTemplate string = func() string {
+		format, _ := changelog.DetectPullRequestEntryFormat(changelogName)
+
+		return format
+	}()
 
 	release    string
 	baseBranch string = func() string {