1 files changed, 202 insertions, 0 deletions
diff --git a/spdxconv.go b/spdxconv.go
new file mode 100644
index 0000000..5f28e5a
--- /dev/null
+++ b/spdxconv.go
@@ -0,0 +1,202 @@
+// SPDX-License-Identifier: GPL-3.0-only
+// SPDX-FileCopyrightText: 2025 M. Shulhan <ms@kilabit.info>
+
+package spdxconv
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"git.sr.ht/~shulhan/pakakeh.go/lib/git"
+	"git.sr.ht/~shulhan/pakakeh.go/lib/ini"
+)
+
+// SPDXConv the main type for converting files to SPDX format.
+type SPDXConv struct {
+	scm sourceCodeManagement
+
+	// dir define the directory that will processed.
+	// `name` is single file inside `dir` to be processed.
+	// If `name` is empty means process all files inside `dir`.
+	dir  string
+	name string
+
+	// scmDir define the root directory for source-code management.
+	// In git, the path that contains the ".git" directory.
+	scmDir string
+
+	cfg config
+}
+
+// Apply the SPDX license headers to all files inside the directory `path` or
+// to single file only.
+func Apply(path string) (err error) {
+	var logp = `Apply`
+	var conv *SPDXConv
+
+	conv, err = New(path)
+	if err != nil {
+		return fmt.Errorf(`%s: %w`, logp, err)
+	}
+	var listFile []string
+	if conv.name == `` {
+		listFile, err = conv.scanFiles([]string{conv.dir})
+	} else {
+		listFile, err = conv.scanFile(conv.dir, conv.name)
+	}
+	if err != nil {
+		return fmt.Errorf(`%s: %w`, logp, err)
+	}
+
+	var pathFile string
+	for _, pathFile = range listFile {
+		conv.convert(pathFile)
+	}
+	return nil
+}
+
+// New initialize new instance of SPDXConv
+func New(path string) (conv *SPDXConv, err error) {
+	var logp = `New`
+
+	path, err = filepath.Abs(path)
+	if err != nil {
+		return nil, fmt.Errorf(`%s: %w`, logp, err)
+	}
+
+	conv = &SPDXConv{}
+	var fi os.FileInfo
+	fi, err = os.Stat(path)
+	if err != nil {
+		return nil, fmt.Errorf(`%s: %w`, logp, err)
+	}
+
+	if fi.IsDir() {
+		conv.dir = path
+	} else {
+		conv.dir, conv.name = filepath.Split(path)
+	}
+
+	err = conv.loadConfig(conv.dir)
+	if err != nil {
+		return nil, fmt.Errorf(`%s: %w`, logp, err)
+	}
+
+	err = conv.scanForSCM(conv.dir)
+	if err != nil {
+		return nil, fmt.Errorf(`%s: %w`, logp, err)
+	}
+
+	return conv, nil
+}
+
+// loadConfig load the program configuration from file `spdxconv.cfg` in the
+// current directory.
+func (conv *SPDXConv) loadConfig(dir string) (err error) {
+	var logp = `loadConfig`
+	var pathcfg = filepath.Join(dir, `spdxconv.cfg`)
+	var rawcfg []byte
+	rawcfg, err = os.ReadFile(pathcfg)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil
+		}
+		return fmt.Errorf(`%s %s: %w`, logp, pathcfg, err)
+	}
+	err = ini.Unmarshal(rawcfg, &conv.cfg)
+	if err != nil {
+		return fmt.Errorf(`%s %s: %w`, logp, pathcfg, err)
+	}
+	err = conv.cfg.init()
+	if err != nil {
+		return fmt.Errorf(`%s %s: %w`, logp, pathcfg, err)
+	}
+	return nil
+}
+
+// scanForSCM scan for source-code management (SCM) from directory `dir` up
+// until the root.
+// Currently, only support git.
+func (conv *SPDXConv) scanForSCM(dir string) (err error) {
+	var scmDir string
+	var fi os.FileInfo
+	for dir != `/` {
+		scmDir = filepath.Join(dir, `.git`)
+		fi, err = os.Stat(scmDir)
+		if err != nil {
+			if os.IsNotExist(err) {
+				continue
+			}
+			return err
+		}
+		if !fi.IsDir() {
+			continue
+		}
+		conv.scmDir = dir
+		conv.scm, err = git.New(dir)
+		if err != nil {
+			return err
+		}
+		return nil
+	}
+	conv.scm = &dummySCM{}
+	return nil
+}
+
+// scanFile check if the single file can be processed or not.
+func (conv *SPDXConv) scanFile(dir, name string) (listFile []string, err error) {
+	var pathName = filepath.Join(dir, name)
+	if conv.scm.IsIgnored(pathName) {
+		return nil, nil
+	}
+	listFile = append(listFile, pathName)
+	return listFile, nil
+}
+
+// scanFiles list file to be processed in directory `dir`, recursively.
+// A file ignored by ".gitignore" file will be excluded.
+// A common ignore file or directory name likes ".git", "node_modules", and
+// "vendor"; also will be excluded.
+func (conv *SPDXConv) scanFiles(listDir []string) (listFile []string, err error) {
+	var commonIgnore = map[string]struct{}{
+		`.git`:         struct{}{},
+		`node_modules`: struct{}{},
+		`vendor`:       struct{}{},
+	}
+	var dir string
+	var listde []os.DirEntry
+	var de os.DirEntry
+	var ok bool
+	for len(listDir) != 0 {
+		dir = listDir[0]
+		listDir = listDir[1:]
+
+		listde, err = os.ReadDir(dir)
+		if err != nil {
+			return listFile, err
+		}
+		for _, de = range listde {
+			var name = de.Name()
+			if conv.scm.IsIgnored(name) {
+				continue
+			}
+			_, ok = commonIgnore[name]
+			if ok {
+				continue
+			}
+			var pathName = filepath.Join(dir, name)
+			if de.IsDir() {
+				listDir = append(listDir, pathName)
+				continue
+			}
+			listFile = append(listFile, pathName)
+		}
+	}
+	return listFile, nil
+}
+
+// convert the given pathFile to SPDX license format.
+func (conv *SPDXConv) convert(pathFile string) {
+
+}