feat(release): automate release preparation

internal/releaseprep/releaseprep.go

@@ -0,0 +1,90 @@
+package releaseprep
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+)
+
+var versionPattern = regexp.MustCompile(`const String = "[^"]+"`)
+
+func Prepare(rootDir, version, releaseDate string) error {
+	normalizedVersion := strings.TrimPrefix(strings.TrimSpace(version), "v")
+	if normalizedVersion == "" {
+		return fmt.Errorf("version must not be empty")
+	}
+
+	releaseDate = strings.TrimSpace(releaseDate)
+	if releaseDate == "" {
+		return fmt.Errorf("release date must not be empty")
+	}
+
+	if err := updateVersionFile(rootDir, normalizedVersion); err != nil {
+		return err
+	}
+
+	if err := updateChangelog(rootDir, normalizedVersion, releaseDate); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func updateVersionFile(rootDir, version string) error {
+	path := filepath.Join(rootDir, "internal", "homesick", "version", "version.go")
+	contents, err := os.ReadFile(path)
+	if err != nil {
+		return fmt.Errorf("read version file: %w", err)
+	}
+
+	updated := versionPattern.ReplaceAllString(string(contents), fmt.Sprintf(`const String = %q`, version))
+	if updated == string(contents) {
+		return fmt.Errorf("version constant not found in %s", path)
+	}
+
+	if err := os.WriteFile(path, []byte(updated), 0o644); err != nil {
+		return fmt.Errorf("write version file: %w", err)
+	}
+
+	return nil
+}
+
+func updateChangelog(rootDir, version, releaseDate string) error {
+	path := filepath.Join(rootDir, "changelog.md")
+	contents, err := os.ReadFile(path)
+	if err != nil {
+		return fmt.Errorf("read changelog: %w", err)
+	}
+
+	text := string(contents)
+	unreleasedHeader := "## [Unreleased]\n"
+	start := strings.Index(text, unreleasedHeader)
+	if start == -1 {
+		return fmt.Errorf("unreleased section not found in changelog")
+	}
+
+	afterHeader := start + len(unreleasedHeader)
+	nextSectionRelative := strings.Index(text[afterHeader:], "\n## [")
+	if nextSectionRelative == -1 {
+		nextSectionRelative = len(text[afterHeader:])
+	}
+	nextSectionStart := afterHeader + nextSectionRelative
+	unreleasedBody := strings.TrimLeft(text[afterHeader:nextSectionStart], "\n")
+
+	newSection := fmt.Sprintf("## [%s] - %s\n", version, releaseDate)
+	if strings.TrimSpace(unreleasedBody) != "" {
+		newSection += "\n" + unreleasedBody
+		if !strings.HasSuffix(newSection, "\n") {
+			newSection += "\n"
+		}
+	}
+
+	updated := text[:afterHeader] + "\n" + newSection + text[nextSectionStart:]
+	if err := os.WriteFile(path, []byte(updated), 0o644); err != nil {
+		return fmt.Errorf("write changelog: %w", err)
+	}
+
+	return nil
+}