feat(generate): Add manpage generator

.gitignore

@@ -1,3 +1,4 @@
 .idea/
 changelog-generator
 /completions/
+/manpages/

.goreleaser.yaml

@@ -2,6 +2,7 @@ project_name: changelog-generator
 before:
   hooks:
     - go run ./internal/generate/completions --date={{ .CommitDate }}
+    - go run ./internal/generate/manpages --version={{ .Version }} --date={{ .CommitDate }}
 builds:
   - env:
       - CGO_ENABLED=0

internal/generate/manpages/main.go

@@ -0,0 +1,96 @@
+package main
+
+import (
+	"compress/gzip"
+	"io"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/gabe565/changelog-generator/cmd"
+	"github.com/spf13/cobra/doc"
+	flag "github.com/spf13/pflag"
+)
+
+func main() {
+	flags := flag.NewFlagSet("", flag.ContinueOnError)
+
+	var version string
+	flags.StringVar(&version, "version", "beta", "Version")
+
+	var dateParam string
+	flags.StringVar(&dateParam, "date", time.Now().Format(time.RFC3339), "Build date")
+
+	if err := flags.Parse(os.Args); err != nil {
+		panic(err)
+	}
+
+	if err := os.RemoveAll("manpages"); err != nil {
+		panic(err)
+	}
+
+	if err := os.MkdirAll("manpages", 0o755); err != nil {
+		panic(err)
+	}
+
+	rootCmd := cmd.New("", "")
+	rootName := rootCmd.Name()
+
+	date, err := time.Parse(time.RFC3339, dateParam)
+	if err != nil {
+		panic(err)
+	}
+
+	header := doc.GenManHeader{
+		Title:   strings.ToUpper(rootName),
+		Section: "1",
+		Date:    &date,
+		Source:  rootName + " " + version,
+		Manual:  "User Commands",
+	}
+
+	if err := doc.GenManTree(rootCmd, &header, "manpages"); err != nil {
+		panic(err)
+	}
+
+	if err := filepath.Walk("manpages", func(path string, info fs.FileInfo, err error) error {
+		if err != nil || info.IsDir() {
+			return err
+		}
+
+		in, err := os.Open(path)
+		if err != nil {
+			return err
+		}
+
+		out, err := os.Create(path + ".gz")
+		if err != nil {
+			return err
+		}
+		gz := gzip.NewWriter(out)
+
+		if _, err := io.Copy(gz, in); err != nil {
+			return err
+		}
+
+		if err := in.Close(); err != nil {
+			return err
+		}
+		if err := os.Remove(path); err != nil {
+			return err
+		}
+
+		if err := gz.Close(); err != nil {
+			return err
+		}
+		if err := out.Close(); err != nil {
+			return err
+		}
+
+		return nil
+	}); err != nil {
+		panic(err)
+	}
+}